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Fluid-structure interaction in abdominal aortic aneurysms: effects of asymmetry and wall thickness
Background Abdominal aortic aneurysm (AAA) is a prevalent disease which is of significant concern because of the morbidity associated with the continuing expansion of the abdominal aorta and its ultimate rupture. The transient interaction between blood flow and the wall contributes to wall stress which, if it exceeds the failure strength of the dilated arterial wall, will lead to aneurysm rupture. Utilizing a computational approach, the biomechanical environment of virtual AAAs can be evaluated to study the affects of asymmetry and wall thickness on this stress, two parameters that contribute to increased risk of aneurysm rupture. Methods Ten virtual aneurysm models were created with five different asymmetry parameters ranging from ? = 0.2 to 1.0 and either a uniform or variable wall thickness to study the flow and wall dynamics by means of fully coupled fluid-structure interaction (FSI) analyses. The AAA wall was designed to have a (i) uniform 1.5 mm thickness or (ii) variable thickness ranging from 0.5 ¢ 1.5 mm extruded normally from the boundary surface of the lumen. These models were meshed with linear hexahedral elements, imported into a commercial finite element code and analyzed under transient flow conditions. The method proposed was then compared with traditional computational solid stress techniques on the basis of peak wall stress predictions and cost of computational effort. Results The results provide quantitative predictions of flow patterns and wall mechanics as well as the effects of aneurysm asymmetry and wall thickness heterogeneity on the estimation of peak wall stress. These parameters affect the magnitude and distribution of Von Mises stresses; varying wall thickness increases the maximum Von Mises stress by 4 times its uniform thickness counterpart. A pre-peak systole retrograde flow was observed in the AAA sac for all models, which is due to the elastic energy stored in the compliant arterial wall and the expansion force of the artery during systole. Conclusion Both wall thickness and geometry asymmetry affect the stress exhibited by a virtual AAA. Our results suggest that an asymmetric AAA with regional variations in wall thickness would be exposed to higher mechanical stresses and an increased risk of rupture than a more fusiform AAA with uniform wall thickness. Therefore, it is important to accurately reproduce vessel geometry and wall thickness in computational predictions of AAA biomechanics. PMID:16271141
Scotti, Christine M; Shkolnik, Alexander D; Muluk, Satish C; Finol, Ender A
Semiautomatic vessel wall detection and quantification of wall thickness in computed tomography images of human abdominal aortic aneurysms
Purpose: Quantitative measurements of wall thickness in human abdominal aortic aneurysms (AAAs) may lead to more accurate methods for the evaluation of their biomechanical environment. Methods: The authors describe an algorithm for estimating wall thickness in AAAs based on intensity histograms and neural networks involving segmentation of contrast enhanced abdominal computed tomography images. The algorithm was applied to ten ruptured and ten unruptured AAA image data sets. Two vascular surgeons manually segmented the lumen, inner wall, and outer wall of each data set and a reference standard was defined as the average of their segmentations. Reproducibility was determined by comparing the reference standard to lumen contours generated automatically by the algorithm and a commercially available software package. Repeatability was assessed by comparing the lumen, outer wall, and inner wall contours, as well as wall thickness, made by the two surgeons using the algorithm. Results: There was high correspondence between automatic and manual measurements for the lumen area (r=0.978 and r=0.996 for ruptured and unruptured aneurysms, respectively) and between vascular surgeons (r=0.987 and r=0.992 for ruptured and unruptured aneurysms, respectively). The authors' automatic algorithm showed better results when compared to the reference with an average lumen error of 3.69%, which is less than half the error between the commercially available application Simpleware and the reference (7.53%). Wall thickness measurements also showed good agreement between vascular surgeons with average coefficients of variation of 10.59% (ruptured aneurysms) and 13.02% (unruptured aneurysms). Ruptured aneurysms exhibit significantly thicker walls (1.78{+-}0.39 mm) than unruptured ones (1.48{+-}0.22 mm), p=0.044. Conclusions: While further refinement is needed to fully automate the outer wall segmentation algorithm, these preliminary results demonstrate the method's adequate reproducibility and low interobserver variability.
Shum, Judy; DiMartino, Elena S.; Goldhammer, Adam; Goldman, Daniel H.; Acker, Leah C.; Patel, Gopal; Ng, Julie H.; Martufi, Giampaolo; Finol, Ender A. [Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Department of Biomedical Engineering and Institute for Complex Engineered Systems, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Department of Electrical and Computer Engineering and Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Department of Mechanical Engineering and Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Institute for Complex Engineered Systems, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Department of Electrical and Computer Engineering and Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Department of Mechanical Engineering and Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Institute for Complex Engineered Systems, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Department of Biomedical Engineering and Department of Mechanical Engineering, Institute for Complex Engineered Systems, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)
Investigating muscle regeneration with a dermis/small intestinal submucosa scaffold in a rat full-thickness abdominal wall defect model.
Repair of large complex ventral wall hernias is challenging and outcomes are often poor due to hernia recurrence and compromised abdominal wall function. Currently, biological grafts are used to assist in repairing these complex hernias. Dermis grafts are often chosen because of their mechanical characteristics; however, dermis does not have the ability to promote the muscle regeneration needed to regain abdominal wall function. In contrast, small intestinal submucosa (SIS) grafts have been shown to promote muscle generation in volumetric muscle loss (VML) models. Hence, the objective of this study is to investigate the extent to which SIS grafts can be used together with dermis grafts to repair and promote muscle regeneration in a full-thickness abdominal wall defect in a rat model. The dermis layer is intended to mechanically bridge the defect and support constructive tissue remodeling while the SIS is intended to degrade and promote neo-muscle formation. After 16 weeks of implantation, we found only a small amount of vascularized muscle (<10% of the defect area) in the repaired defects. No significant difference in defect muscle area was found between the groups receiving the dermis?+?SIS scaffolds and the control (dermis alone) group. Our findings indicate that the SIS constructions investigated could not promote appreciable muscle regeneration in this rigorous animal model of VML and incomplete abdominal closure. Future investigation into combination scaffold, cell and molecular therapies would be warranted to address the need for functional muscle regeneration in challenging clinical conditions such as complex abdominal wall repair. PMID:24889422
Ma, Jinjin; Sahoo, Sambit; Baker, Andrew R; Derwin, Kathleen A
Pedicled full-thickness abdominal flap combined with skin grafting for the reconstruction of anterior chest wall defect following major electrical burn.
Successful reconstruction of extensive anterior chest wall defect following major electrical burn represents a very challenging surgery. Herein we report the first case using pedicled full-thickness abdominal flap combined with skin grafting to treat this injury with severe infection and exposure of pericardium and ribs in a Chinese patient. Following the performance of chest debridement to remove necrotic and infected tissues and the injection of broad-spectrum antibiotics to reduce infection, a pedicled full-thickness abdominal flap was used to cover the exposed pericardium and ribs, and skin grafting from the right leg of the patient was done to cover the exposed vital tissues. The patient was followed up for a total of 3Ę5 years, and satisfactory cosmetic and functional outcomes were obtained without complications. This report provides an effective method for the surgeons who encounter similar cases where reconstruction of extensive anterior chest wall is required. PMID:23490336
Zhao, Jing-Chun; Xian, Chun-Jing; Yu, Jia-Ao; Shi, Kai
A thick-walled fluid-solid-growth model of abdominal aortic aneurysm evolution: application to a patient-specific geometry.
We propose a novel thick-walled fluid-solid-growth (FSG) computational framework for modeling vascular disease evolution. The arterial wall is modeled as a thick-walled nonlinearly elastic cylindrical tube consisting of two layers corresponding to the media-intima and adventitia, where each layer is treated as a fiber-reinforced material with the fibers corresponding to the collagenous component. Blood is modeled as a Newtonian fluid with constant density and viscosity; no slip and no-flux conditions are applied at the arterial wall. Disease progression is simulated by growth and remodeling (G&R) of the load bearing constituents of the wall. Adaptions of the natural reference configurations and mass densities of constituents are driven by deviations of mechanical stimuli from homeostatic levels. We apply the novel framework to model abdominal aortic aneurysm (AAA) evolution. Elastin degradation is initially prescribed to create a perturbation to the geometry which results in a local decrease in wall shear stress (WSS). Subsequent degradation of elastin is driven by low WSS and an aneurysm evolves as the elastin degrades and the collagen adapts. The influence of transmural G&R of constituents on the aneurysm development is analyzed. We observe that elastin and collagen strains evolve to be transmurally heterogeneous and this may facilitate the development of tortuosity. This multiphysics framework provides the basis for exploring the influence of transmural metabolic activity on the progression of vascular disease. PMID:25473877
Grytsan, Andrii; Watton, Paul N; Holzapfel, Gerhard A
Behaviour of a New Composite Mesh for the Repair of Full-Thickness Abdominal Wall Defects in a Rabbit Model
Introduction Composite biomaterials designed for the repair of abdominal wall defects are composed of a mesh component and a laminar barrier in contact with the visceral peritoneum. This study assesses the behaviour of a new composite mesh by comparing it with two latest-generation composites currently used in clinical practice. Methods Defects (7x5cm) created in the anterior abdominal wall of New Zealand White rabbits were repaired using a polypropylene mesh and the composites: PhysiomeshTM; VentralightTM and a new composite mesh with a three-dimensional macroporous polyester structure and an oxidized collagen/chitosan barrier. Animals were sacrificed on days 14 and 90 postimplant. Specimens were processed to determine host tissue incorporation, gene/protein expression of neo-collagens (RT-PCR/immunofluorescence), macrophage response (RAM-11-immunolabelling) and biomechanical resistance. On postoperative days 7/14, each animal was examined laparoscopically to quantify adhesions between the visceral peritoneum and implant. Results The new composite mesh showed the lowest incidence of seroma in the short term. At each time point, the mesh surface covered with adhesions was greater in controls than composites. By day 14, the implants were fully infiltrated by a loose connective tissue that became denser over time. At 90 days, the peritoneal mesh surface was lined with a stable mesothelium. The new composite mesh induced more rapid tissue maturation than PhysiomeshTM, giving rise to a neoformed tissue containing more type I collagen. In VentralightTM the macrophage reaction was intense and significantly greater than the other composites at both follow-up times. Tensile strengths were similar for each biomaterial. Conclusions All composites showed optimal peritoneal behaviour, inducing good peritoneal regeneration and scarce postoperative adhesion formation. A greater foreign body reaction was observed for VentralightTM. All composites induced good collagen deposition accompanied by optimal tensile strength. The three-dimensional macroporous structure of the new composite mesh may promote rapid tissue regeneration within the mesh. PMID:24236192
Pascual, Gemma; Sotomayor, Sandra; RodrĒguez, Marta; Bayon, Yves; Bell¾n, Juan M.
A New Rat Model for Orthotopic Abdominal Wall Allotransplantation
Background: Abdominal wall, one of the most commonly transplanted composite tissues, is less researched and lacking animal models. Its clinical necessities were emphasized in multiple case series to reconstruct large abdominal defects. Previous animal models have only studied components of the abdominal wall transplant. We describe findings from a new model that more likely reflect clinical transplantation. Methods: Full-thickness hemiabdominal wall flap was procured from Brown Norway (BN) rats and transplanted to an orthotopic defect on Lewis rats. Three groups were studied: group 1: Lewis to Lewis syngeneic; group 2: BN to Lewis control; and group 3: BN to Lewis with postoperative cyclosporine. Vascular imaging and cross vessel section were performed along with full-thickness abdominal wall. Immune cell profiling with flow cytometry at different time points was studied in all groups. Results: Syngeneic group had no rejection. Control group consistently showed rejection around postoperative day 6. With cyclosporine treatment, however, transplant and recipient tissue integration was observed. Flow cytometry revealed that innate immunity is responsible for the initial inflammatory events following abdominal wall engraftment. Adaptive immunity cells, specifically interferon-?-producing T helper (Th) 1 and interleukin-17-producing Th17 cells, dramatically and positively correlate with rejection progression of abdominal wall transplants. Conclusions: Technical, histological, and immunological aspects of a new rat model are described. These results give clues to what occurs in human abdominal wall transplantation. In addition, Th1, a proinflammatory cell, was found to be a potential biomarker for allograft rejection. PMID:25289329
Lao, William W.; Wang, Yen-Ling; Ramirez, Alejandro E.; Cheng, Hui-Yun
[A case of abdominal wall actinomycosis].
Actinomycosis is a chronic suppurative granulomatous infectious disease caused by actinomyces species that is characterized by formation of characteristic clumps called as sulfur granules. Abdominal actinomycosis is a rare disease and is often difficult to diagnose before operation. Abdominal actinomycosis infiltrating into the abdominal wall and adhering to the colon is even rarer. Most abdominal actinomycosis develops after operation, trauma or inflammatory bowel disease, and is also considered as an opportunistic infection in immunocompromised patient with underlying malignancy, diabetes mellitus, human immunodefidiency virus infection, etc. Actinomycosis is diagnosed based on histologic demonstration of sulfur granules in surgically resected specimen or pus, and treatment consists of long-term penicillin based antibiotics therapy with or without surgical resection. Herein, we report an unusual case of abdominal wall actinomycosis which developed in a patient after acupuncture and presented as abdominal wall mass that was first mistaken for abdominal wall invasion of diverticulum perforation. PMID:25896158
Kim, Kyung Hoon; Lee, Jin Soo; Cho, Hyeong Jun; Choi, Seung Bong; Cheung, Dae Young; Kim, Jin Il; Lee, In Kyu
Reconstruction of disruption of the abdominal wall in burn patients.
Two patients with extensive destruction of the full thickness of the abdominal wall and associated intra-abdominal injuries were encountered. One case resulted from burns to a patient pinned under an automobile in contact with the muffler; the other was injured as a result of penetration of the abdominal wall by a railroad coupling and was also burned in an associated welding accident at the same time. Extensive staged debridement and repair of intra-abdominal injuries in several procedures were required in case 1. Closure was eventually achieved with serial applications of mesh and split-thickness autografting. In case 2, an initial attempt at flap closure failed. Coverage initially was obtained with silicone mesh followed by split-thickness grafting. We report successful management of two of these difficult reconstructive challenges. PMID:10190445
Still, J M; Dimick, A R; Dawson, J; Law, E
Giant Subcutaneous Leiomyosarcoma of Anterior Abdominal Wall
Subcutaneous leiomyosarcomas are rare tumors accounting for 1% to 2% of all superficial soft tissue malignancies. Although they may arise anywhere in the body, they most frequently occur in the lower extremities. The incidence of subcutaneous LMS affecting the anterior abdominal wall is very rare. We herein report the case of a patient with a giant subcutaneous leiomyosarcoma arising in the anterior abdominal wall. It was diagnosed by histopathology and immunohistochemistry and treated accordingly. PMID:25506027
Large Abdominal Wall Endometrioma Following Laparoscopic Hysterectomy
Background: Endometriosis is a common condition in women that affects up to 45% of patients in the reproductive age group by causing pelvic pain. It is characterized by the presence of endometrial tissue outside the uterine cavity and is rarely found subcutaneously or in abdominal incisions, causing it to be overlooked in patients with abdominal pain. Methods: A 45-year-old woman presented with lower abdominal pain 2 years following a laparoscopic supracervical hysterectomy. She was found to have incidental cholelithiasis and a large abdominal mass suggestive of a significant ventral hernia on CT scan. Results: Due to the peculiar presentation, surgical intervention took place that revealed a large 9cmū7.6cmū6.2cm abdominal wall endometrioma. Conclusion: Although extrapelvic endometriosis is rare, it should be entertained in the differential diagnosis for the female patient who presents with an abdominal mass and pain and has a previous surgical history. PMID:21902990
Borncamp, Erik; Mehaffey, Philip; Rotman, Carlos
Flap Coverage of Anterior Abdominal Wall Defects
Reconstruction of complex defects of the anterior abdomen is both challenging and technically demanding for reconstructive surgeons. Advancements in the use of pedicle and free tissue transfer along with the use of bioprosthetic and synthetic meshes have provided for novel approaches to these complex defects. Accordingly, detailed knowledge of abdominal wall and lower extremity anatomy in combination with insight into the design, implementation, and limitations of various flaps is essential to solve these complex clinical problems. Although these defects can be attributed to a myriad of etiologic factors, the objectives in abdominal wall reconstruction are consistent and include the restoration of abdominal wall integrity, protection of intraabdominal viscera, and the prevention of herniation. In this article, the authors review pertinent anatomy and the various local, regional, and distant flaps that can be utilized in the reconstruction of these complex clinical cases of the anterior abdomen. PMID:23372457
Sacks, Justin M.; Broyles, Justin M.; Baumann, Donald P.
Abdominal wall repair using human acellular dermis
BackgroundThe surgical repair of abdominal wall defects that cannot be closed primarily in contaminated fields is a difficult problem. The use of nonabsorbable synthetic materials usually is contraindicated in this setting because of the risk for colonization and chronic infection of the mesh. In this study we sought to determine the safety and efficacy of implanted human acellular dermal graft
Charles F. Bellows; Daniel Albo; David H. Berger; Samir S. Awad
Anterior Abdominal Wall Haemangioma with Inguinal Extension
Haemangioma are common benign vascular tumour but Intramuscular haemangiomas are rare tumours comprising less than 1% of all. The most frequent sites are extremities, head and neck whereas abdominal wall is a quiet rare location. Ultrasonography is an appropriate initial diagnostic modality and MRI is the investigation of choice. A rare case presented to us as Intramuscular haemangioma of anterior abdominal wall with inguinal extension. Ultrasonography with Doppler study and MRI was suggestive of same finding. Intraoperatively patient had huge haemangioma involving external oblique, internal oblique and transverse abdominus muscle. Wide local excision with meshplasty was done as part of muscle had to be removed. Histology confirmed the diagnosis of Intramuscular Haemangioma. PMID:25584266
Dubhashi, Siddharth P; Choudhary, Kaushal
Temporary abdominal closure followed by definitive abdominal wall reconstruction of the open abdomen
BackgroundInability to close the abdominal wall after laparotomy for trauma may occur as a result of visceral edema, retroperitoneal hematoma, use of packing, and traumatic loss of tissue. Often life-saving, decompressive laparotomy and temporary abdominal closure require later restoration of anatomic continuity of the abdominal wall.
Thomas R. Howdieshell; Charles D. Proctor; Erez Sternberg; Jorge I. Cuķ; J. Sheppard Mondy; Michael L. Hawkins
A rare nonincisional lateral abdominal wall hernia.
A 68-year-old woman presented a rare lateral abdominal wall hernia. Three month before admission to Chungbuk National University Hospital, she found a large protruding mass measuring 8 cm in diameter in the midaxillary line just below the costal margin upon heavy coughing. She had no history of abdominal trauma, infection, or operation previously. The mass was easily reduced manually or by position change to left lateral decubitus. CT scan showed a defect of the right transversus abdominis muscle and internal oblique muscle at the right flank with omental herniation. Its location is different from that of spigelian hernia or lumbar hernia. The peritoneal lining of the hernia sac was smooth and there was no evidence of inflammation or adhesion. The hernia was successfully repaired laparoscopically using Parietex composite mesh with an intraperitoneal onlay mesh technique. The patient was discharged uneventfully and did not show any evidence of recurrence at follow-up visits. PMID:25692123
Kim, Dong-Ju; Park, Jin-Woo
A rare nonincisional lateral abdominal wall hernia
A 68-year-old woman presented a rare lateral abdominal wall hernia. Three month before admission to Chungbuk National University Hospital, she found a large protruding mass measuring 8 cm in diameter in the midaxillary line just below the costal margin upon heavy coughing. She had no history of abdominal trauma, infection, or operation previously. The mass was easily reduced manually or by position change to left lateral decubitus. CT scan showed a defect of the right transversus abdominis muscle and internal oblique muscle at the right flank with omental herniation. Its location is different from that of spigelian hernia or lumbar hernia. The peritoneal lining of the hernia sac was smooth and there was no evidence of inflammation or adhesion. The hernia was successfully repaired laparoscopically using Parietex composite mesh with an intraperitoneal onlay mesh technique. The patient was discharged uneventfully and did not show any evidence of recurrence at follow-up visits. PMID:25692123
Kim, Dong-Ju
Porcine Abdominal Wall Simulator for Laparotomy Incision and Closure.
We describe an economical and simple abdominal wall model that provides a realistic experience for trainees as they develop the skills of creating an abdominal incision through the midline, followed by closure of the fascia and skin. PMID:25377215
Khan, Sadaf; Cipriano, Cassie; Marks, Jeffrey M; Schomisch, Steve J
A single center experience of abdominal wall graft rejection after combined intestinal and abdominal wall transplantation.
We report our outcomes following combined intestinal and abdominal wall transplantation, focusing on the presentation and treatment of acute rejection of the abdominal wall vascularized composite allograft (VCA). Retrospective analysis of all patients with combined intestinal/VCA transplantation was undertaken. Graft abnormalities were documented photographically and biopsies taken, with histological classification of rejection according to Banff 2007 guidelines. We have performed five combined intestinal and abdominal wall transplants to date. Two patients developed erythematous, maculopapular to papular eruptions confined to the VCA, histologically confirmed as grade II/III rejection, yet with normal bowel on endoscopy. Both patients' rashes resolved within 72 h of increasing immunosuppressive treatment. One patient later developed a recurrence of the rash, confirmed as skin rejection, but did not immediately seek medical attention. Treatment was therefore delayed, and mild intestinal rejection developed. We describe the rash associated with VCA rejection, and propose that while the skin of an abdominal wall VCA may reject independently of the intestinal allograft, delay in treatment of rejection episodes may result in rejection of the intestinal graft. PMID:23837458
Allin, B S R; Ceresa, C D L; Issa, F; Casey, G; Espinoza, O; Reddy, S; Sinha, S; Giele, H; Friend, P; Vaidya, A
Remote revascularization of abdominal wall transplants using the forearm.
Primary abdominal wall closure following small bowel transplantation is frequently impossible due to contraction of the abdominal domain. Although abdominal wall transplantation was reported 10 years ago this, technique has not been widely adopted, partly due to its complexity, but largely because of concerns that storing the abdominal allograft until the end of a prolonged intestinal transplant procedure would cause severe ischemia-reperfusion injury. We report six cases of combined small bowel and abdominal wall transplantation where the ischemic time was minimized by remotely revascularizing the abdominal wall on the forearm vessels, synchronous to the intestinal procedure. When the visceral transplant was complete, the abdominal wall was removed from the forearm and revascularized on the abdomen (n = 4), or used to close the abdomen while still vascularized on the forearm (n = 2). Primary abdominal wall closure was achieved in all. Mean cold ischemia was 305 min (300-330 min), and revascularization on the arm was 50 min (30-60 min). Three patients had proven abdominal wall rejection, all treated successfully. Immediate revascularization of the abdominal wall allograft substantially reduces cold ischemia without imposing constraints on the intestinal transplant. Reducing storage time may also have benefits with respect to ischemia-reperfusion-related graft immunogenicity. PMID:24797611
Giele, H; Bendon, C; Reddy, S; Ramcharan, R; Sinha, S; Friend, P; Vaidya, A
Tensor fascia lata musculocutaneous flap for abdominal wall reconstruction
We report a case of abdominal wall reconstruction following excision of irradiated skin and a ventral hernia. A very large tensor fascia lata musculocutaneous flap was used with good results. The anatomical features of this flap make it an excellent method of abdominal wall reconstruction.
Peled, I.J.; Kaplan, H.Y.; Herson, M.; Wexler, M.R.
Anomalously thick domain walls in ferroelectrics
NASA Astrophysics Data System (ADS)
Using the Landau theory we demonstrate the possibility of unusual, anomalously thick ferroelectric domain walls, where the order parameter rotates with a nearly constant modulus as in ferromagnets. The effect occurs in 90? charged domain walls and is associated with the easy polarization rotation near the morphotropic phase boundary. This magneticlike profile is unique to charged domain walls due to the availability of free charges which screen the depolarizing field resulting from polarization rotation. In contrast to previously known thick ferroelectric domain walls, the large thickness of 90? charged domain walls near the morphotropic boundary is predicted for a wide temperature interval. This property may be favorable for potential applications.
Yudin, P. V.; Gureev, M. Y.; Sluka, T.; Tagantsev, A. K.; Setter, N.
Effect of intraluminal thrombus on abdominal aortic aneurysm wall stress
Purpose: Abdominal aortic aneurysms (AAAs) rupture when the wall stress exceeds the strength of the vascular tissue. Intraluminal thrombus may absorb tension and reduce AAA wall stress. This study was performed to test the hypothesis that intraluminal thrombus can significantly reduce AAA wall stress.Methods: AAA wall stresses were determined by axisymmetric finite element analysis. Model AAAs had external diameters ranging
William R. Mower; William J. Qui±ones; Sanjiv S. Gambhir
Thermalization in thick wall electroweak baryogenesis
In models of thick wall electroweak baryogenesis a common assumption is that the plasma interacting with the expanding Higgs bubble wall during the electroweak phase transition is in kinetic equilibrium (or close to it). We point out that, in addition to the requirement of low wall velocity, kinetic equilibrium requires that the change in the momentum of the particles due to the force exerted by the wall should be much less than that due to scattering as the plasma passes through the wall. We investigate whether this condition is satisfied for charginos and neutralinos participating in thick wall supersymmetric electroweak baryogenesis.
Bhatt, Jitesh; Rangarajan, Raghavan [Theoretical Physics Division, Physical Research Laboratory Navrangpura, Ahmedabad 380 009 (India)
[Abdominal wall injury - risk of seat belt use].
Abdominal seat belt marks can be an indication of abdominal wall rupture. The focused assessment with sonography for trauma (FAST) and computed tomography (CT) scanning are the diagnostic tools of choice in hemodynamically stable patients. The typical mechanism of trauma frequently leads to additional intra-abdominal injuries, spinal injuries and in some cases aortic rupture. Abdominal wall injuries of gradeĀIV according to Dennis should be surgically treated. The increasing numbers of obese vehicle occupants and the resulting special risk of injury warrant optimization of technical restraint systems. PMID:23896762
Bachmann, S; Schrem, H; Mommsen, P; Gaulke, R; Klempnauer, J; Bektas, H; Krettek, C; Zeckey, C
Correlation between Peak Expiratory Flow and Abdominal Muscle Thickness
[Purpose] The purpose of this study was to determine whether forced expiration is correlated with abdominal muscle thickness. [Subjects] Twenty-three healthy male volunteers participated in this study. [Methods] The peak expiratory flow (PEF) was obtained using a peak flow meter with subjects in the sitting position. The thicknesses of the right rectus abdominis, external oblique, internal oblique, and transverse abdominis muscles were measured using B-mode ultrasonography at the end of a relaxed expiration in the supine position. [Results] Among the abdominal muscles, only the thickness of the external oblique muscle displayed a significant correlation with PEF. [Conclusion] It appears that the thickness of the external oblique muscle might be associated with PEF during forced expiration. PMID:25435702
Ishida, Hiroshi; Kobara, Kenichi; Osaka, Hiroshi; Suehiro, Tadanobu; Ito, Tomotaka; Kurozumi, Chiharu; Watanabe, Susumu
Modern reconstructive techniques for abdominal wall defects after oncologic resection.
Resection of abdominal wall tumors often leaves patients with debilitating soft tissue defects. Modern reconstructive techniques can be used to restore abdominal wall integrity. In this article, we present an overview of preoperative patient evaluation, analysis of the defect, surgical planning, and the spectrum of available surgical techniques, ranging from simple to complex. The established clinical evidence in the field of abdominal wall reconstruction is summarized and a case example is provided. J. Surg. Oncol. 2015 111:587-598. ® 2014 Wiley Periodicals, Inc. PMID:25371050
Khansa, Ibrahim; Janis, Jeffrey E
[Closing the abdominal wall - challenges and possible solutions].
The most common complications after abdominal surgery - wound infections and the development of incisional hernia - are associated with the opening and closing of the abdominal wall. Depending on the selection of patients, wound infection rates of up to 19?% and hernia rates of up to 38?% are reported. Based on a summary of the actual literature, the abdominal wall should be closed with continuous slowly absorbable sutures with a suture length to wound length ratio of over 4 using small stitches. While antiseptic suture material may help to reduce wound infections after abdominal incision, preventing the development of incisional hernia is still a unsolved problem. As there is still no standard surgical technique for abdominal wall closure, surgeons should pay greater attention to the standardisation and documentation of techniques and wound care. PMID:22086773
Justinger, C; Schilling, M K
Pedicled omental and split skin graft in the reconstruction of the anterior abdominal wall?
INTRODUCTION The POSSG is a pedicled graft based on either the right or left gastro-epiploic arteries. It is used with a dual mesh in reconstruction of full thickness defects of anterior abdominal wall and covered by skin grafts. PRESENTATION OF CASE A recurrent malignant peripheral nerve sheath tumor (MPNST) of the anterior abdominal wall was excised leaving a large defect. The POSSG was used for reconstruction. A large dual mesh was placed to close the defect in the abdominal wall by suturing it to the remnant rim of abdominal muscles. The omental pedicle was brought through a keyhole in the mesh, spread out over the mesh, sutured and covered by split skin grafts. The final graft take was 90 percent. DISCUSSION The POSSG can be used to reconstruct any size of anterior abdominal wall defects due to the malleable nature of omentum. Its prerequisite however is a dual mesh like PROCEED. The POSSG helps keep the more complex musculofasciocutaneous flaps as lifeboats. It can be used singly where multiple musculofasciocutaneous flaps would otherwise have been required. It can be used in patients with poor prognosis of underlying malignancy. It may be used by general surgeons due to familiarity with anatomy of the relevant structures and lack of need for microsurgical skill. CONCLUSION The POSSG can be used in reconstruction of abdominal wall defects of any size by general surgeons. PMID:24566428
Manay, Priyadarshini; Khajanchi, Monty; Prajapati, Ram; Satoskar, Rajeev
Abdominal wall and intra-peritoneal abscess by Propionibacterium avidum as a complication of abdominal parietoplasty.
Propionibacteria are organisms of low pathogenicity and only a minority of clinical Propionibacterium isolates is clinically significant. Herein, we report a rare case of Propionibacterium avidum abdominal wall and intra-peritoneal abscess that developed in 46-year-old woman after abdominal parietoplasty. PMID:23415274
Janvier, F; Delacour, H; Larrķchķ, S; Abdalla, S; Aubert, P; Mķrens, A
Bullhorn Hernia: A Rare Traumatic Abdominal Wall Hernia
Traumatic abdominal wall hernia (TAWH) is rare despite the high prevalence of blunt abdominal trauma. Bullhorn hernia occurs as a result of a direct blow to the abdominal wall by the horn of a bull, which disrupts the muscles and fascia and leads to hernia formation. We report a rare case of bullhorn TAWH in a 70-year-old patient who presented with swelling at the left lumbar region. The patient was managed by immediate surgical intervention. A surgeon must have high index of suspicion for the diagnosis of this condition as missed hernias in this setting pose a high risk of strangulation and gangrene.
Singh, Bimaljot; Kumar, Ashwani; Kaur, Adarshpal; Singla, Rachan Lal
[A case of sigmoid colon cancer with abdominal wall abscess].
A 63-year-old man was admitted for an abdominal mass. Computed tomography revealed an abscess (21 ū 20 cm) in the abdominal wall and a tumor in the sigmoid colon. Thus, cancer of the sigmoid colon complicated by an abscess of the abdominal wall was diagnosed. The abscess was drained and transverse colostomy was performed with curative intent. After the intervention, chemotherapy (XELOXū3) was administered. Three months later, sigmoidectomy was performed and the stoma was closed. Macroscopic and microscopic examination of the resected specimen detected no remnants of cancer. In patients with advanced colon cancer and abdominal wall involvement, a two-stage operation and preoperative chemotherapy may be considered essential when curative resection is performed. PMID:25731327
Yamamoto, Yuji; Shimizu, Shinichiro; Maruyama, Takashi; Tanaka, Hajime; Matsuzaki, Hiroshi; Natsume, Toshiyuki; Miyazaki, Akinari; Satoh, Yayoi; Satsuka, Tetsutaro; Yoshioka, Takafumi; Kanada, Yoko; Otsuka, Ryota; Yanagihara, Akitoshi; Yokoyama, Masaya; Kobayashi, Takushi
Delayed dynamic abdominal wall closure following multi-visceral transplantation
INTRODUCTION Primary closure of the abdominal wall following intestinal transplantation or multivisceral transplantation could become a challenging problem in a significant number of patients. PRESENTATION OF CASE A 38-year-old woman with familial adenomatous polyposis (FAP) underwent a multi-visceral transplantation for short gut syndrome. She subsequently developed acute graft rejection that proved resistant to conventional treatment. She was relisted and underwent re-transplantation along with kidney transplantation. Abdominal wall closure could not be achieved because of the large size of the graft and bowel oedema. The wound was initially managed with laparostomy followed by insertion of the delayed dynamic abdominal closure (DDAC) device (Abdominal Retraction Anchor ¢ ABRA« system). Continuous dynamic traction to the wound edges resulted in gradual approximation and complete closure of the abdominal wound was achieved within 3 weeks. DISCUSSION Successful abdominal closure after multivisceral transplantation or isolated intestinal transplantation often requires biological mesh, vascularised flaps or abdominal wall transplantation. DDAC eliminated the need for a prosthetic mesh or skin graft and provided an excellent cosmetic result. Adjustment of the dynamic traction at the bedside minimised the need for multiple returns to the operating theatre. It resulted in a well-healed linear scar without a hernia. CONCLUSION Dynamic traction allows delayed closure of laparotomy resulting in strong and cosmetically sound wound healing with native tissue. PMID:25460454
Iype, Satheesh; Butler, Andrew; Jamieson, Neville; Middleton, Stephen; Jah, Asif
Traumatic breast transposal to the abdominal wall: A case report
Although abdominal wall masses are commonly observed in clinical practice, traumatic breast transposal appearing as an abdominal wall mass is a rare event. The unique phenomenon of a post-traumatic breast growing healthily in the abdominal wall has never previously been reported. The current study presents the case of a 40-year-old female who developed an unusually transposed, but healthy mammary gland in the right upper abdominal wall following a severe pedestrian traffic accident. In that accident, the powerful impact of the car caused multiple right-sided rib fractures, lung injuries and a protruding mass on the right abdominal wall. This sudden onset protruding mass was indicated to be breast tissue by computed tomography imaging and ultrasound scanning. The transposed mammary gland was resected and a pathological examination confirmed that it consisted of normal breast tissue. In this case, the force of the car caused no significant damage or necrosis to the right breast, but instead was sufficient to shift the mammary gland to the abdomen, where it grew healthily 6 months in its new location. This case highlights the capability of the mammary gland to withstand a powerful impact and survive. Moreover, it advances our knowledge of how mammary tissues respond to severe blunt-force impacts. PMID:25120698
Traumatic breast transposal to the abdominal wall: A case report.
Although abdominal wall masses are commonly observed in clinical practice, traumatic breast transposal appearing as an abdominal wall mass is a rare event. The unique phenomenon of a post-traumatic breast growing healthily in the abdominal wall has never previously been reported. The current study presents the case of a 40-year-old female who developed an unusually transposed, but healthy mammary gland in the right upper abdominal wall following a severe pedestrian traffic accident. In that accident, the powerful impact of the car caused multiple right-sided rib fractures, lung injuries and a protruding mass on the right abdominal wall. This sudden onset protruding mass was indicated to be breast tissue by computed tomography imaging and ultrasound scanning. The transposed mammary gland was resected and a pathological examination confirmed that it consisted of normal breast tissue. In this case, the force of the car caused no significant damage or necrosis to the right breast, but instead was sufficient to shift the mammary gland to the abdomen, where it grew healthily 6 months in its new location. This case highlights the capability of the mammary gland to withstand a powerful impact and survive. Moreover, it advances our knowledge of how mammary tissues respond to severe blunt-force impacts. PMID:25120698
Yang, Mei; Xu, Zhe; Liao, Qiulin; Wang, Hong
WSES guidelines for emergency repair of complicated abdominal wall hernias
Emergency repair of complicated abdominal hernias is associated with poor prognosis and a high rate of post-operative complications. A World Society of Emergency Surgery (WSES) Consensus Conference was held in Bergamo in July 2013, during the 2nd Congress of the World Society of Emergency Surgery with the goal of defining recommendations for emergency repair of abdominal wall hernias in adults. This document represents the executive summary of the consensus conference approved by a WSES expert panel. PMID:24289453
Improving the Efficiency of Abdominal Aortic Aneurysm Wall Stress Computations
An abdominal aortic aneurysm is a pathological dilation of the abdominal aorta, which carries a high mortality rate if ruptured. The most commonly used surrogate marker of rupture risk is the maximal transverse diameter of the aneurysm. More recent studies suggest that wall stress from models of patient-specific aneurysm geometries extracted, for instance, from computed tomography images may be a more accurate predictor of rupture risk and an important factor in AAA size progression. However, quantification of wall stress is typically computationally intensive and time-consuming, mainly due to the nonlinear mechanical behavior of the abdominal aortic aneurysm walls. These difficulties have limited the potential of computational models in clinical practice. To facilitate computation of wall stresses, we propose to use a linear approach that ensures equilibrium of wall stresses in the aneurysms. This proposed linear model approach is easy to implement and eliminates the burden of nonlinear computations. To assess the accuracy of our proposed approach to compute wall stresses, results from idealized and patient-specific model simulations were compared to those obtained using conventional approaches and to those of a hypothetical, reference abdominal aortic aneurysm model. For the reference model, wall mechanical properties and the initial unloaded and unstressed configuration were assumed to be known, and the resulting wall stresses were used as reference for comparison. Our proposed linear approach accurately approximates wall stresses for varying model geometries and wall material properties. Our findings suggest that the proposed linear approach could be used as an effective, efficient, easy-to-use clinical tool to estimate patient-specific wall stresses. PMID:25007052
Zelaya, Jaime E.; Goenezen, Sevan; Dargon, Phong T.; Azarbal, Amir-Farzin; Rugonyi, Sandra
Wall thickness measuring method and apparatus
An apparatus for measuring the wall thickness of a nonmagnetic article having a housing supporting a magnet and a contiguous supporting surface. The tubular article and the housing are releasably secured to the supporting surface and a support member of an optical comparator, respectively. To determine the wall thickness of the article at a selected point, a magnetically responsive ball is positioned within the tubular article over said point and retained therein by means of a magnetic field produced by the magnet. Thereafter, an optical comparator is employed to project a magnified image of the ball on a screen and the wall thickness at the selected point is calculated by using a ball surface measurement taken with the comparator in conjunction with a previously determined base line measurement.
Salzer, Leander J. (Los Alamos, NM); Bergren, Donald A. (Los Alamos, NM)
Wall thickness measuring method and apparatus
An apparatus for measuring the wall thickness of a nonmagnetic article having a housing supporting a magnet and a contiguous supporting surface. The tubular article and the housing are releasably secured to the supporting surface and a support member of an optical comparator, respectively. To determine the wall thickness of the article at a selected point, a magnetically responsive ball is positioned within the tubular article over said point and retained therein by means of a magnetic field produced by the magnet. Thereafter, an optical comparator is employed to project a magnified image of the ball on a screen and the wall thickness at the selected point is calculated by using a ball surface measurement taken with the comparator in conjunction with a previously determined base line measurement.
Salzer, L.J.; Bergren, D.A.
Abdominal wall closure after a stomal reversal procedure.
The closure of a temporary stoma involves 2 different surgical procedures: the stoma reversal procedure and the abdominal wall reconstruction of the stoma site. The management of the abdominal wall has different areas that should be analyzed such us how to avoid surgical site infection (SSI), the technique to be used in case of a concomitant hernia at the stoma site or to prevent an incisional hernia in the future, how to deal with the incision when the stoma reversal procedure is performed by laparoscopy and how to close the skin at the stoma site. The aim of this paper is to analyze these aspects in relation to abdominal wall reconstruction during a stoma reversal procedure. PMID:24581880
L¾pez-Cano, Manuel; Pereira, Josķ Antonio; Villanueva, Borja; Vallribera, Francesc; Espin, Eloy; Armengol Carrasco, Manuel; Arb¾s VĒa, MarĒa Antonia; Feliu, Xavier; Morales-Conde, Salvador
Ultrasonography and computed tomography of inflammatory abdominal wall lesions
Twenty-four patients with inflammatory lesions of the abdominal wall were examined by ultrasonography. Nine of these patients underwent computed tomographic (CT) scanning as well. Both ultrasonography and CT clearly delineated the exact location and extent of abdominal wall abscesses. Abscesses were easily differentiated from cellulitis or phlegmon with ultrasound. The peritoneal line was more clearly delineated on ultrasonograms than on CT scans; abscesses were also more distinct on the ultrasonograms because of their low echogenicity compared with the surrounding structures. Gas bubbles, fat density with specific low attenuation values, and underlying inflamed bowel loops in obese patients with Crohn's disease were better delineated by CT.
Yeh, H.C.; Rabinowitz, J.G.
Abdominal wall cellulitis and sepsis secondary to percutaneous cecostomy
We report 1 case of abdominal wall cellulitis and sepsis which developed following percutaneous placement of a Cope catheter\\u000a for cecal decompression in a patient with Ogilvie's syndrome. This case highlights that further laboratory investigation and\\u000a clinical evaluation are needed to determine the safest and most efficacious technique of percutaneous drainage.
Thomas J. Maginot; Philip N. Cascade
On thick domain walls in general relativity
NASA Technical Reports Server (NTRS)
Planar scalar field configurations in general relativity differ considerably from those in flat space. It is shown that static domain walls of finite thickness in curved space-time do not possess a reflection symmetry. At infinity, the space-time tends to the Taub vacuum on one side of the wall and to the Minkowski vacuum (Rindler space-time) on the other. Massive test particles are always accelerated towards the Minkowski side, i.e., domain walls are attractive on the Taub side, but repulsive on the Minkowski side (Taub-vacuum cleaner). It is also proved that the pressure in all directions is always negative. Finally, a brief comment is made concerning the possibility of infinite, i.e., bigger than horizon size, domain walls in our universe. All of the results are independent of the form of the potential V(phi) greater than or equal to 0 of the scalar field phi.
Goetz, Guenter; Noetzold, Dirk
Gas turbine bucket wall thickness control
A core for use in casting a turbine bucket including serpentine cooling passages is divided into two pieces including a leading edge core section and a trailing edge core section. Wall thicknesses at the leading edge and the trailing edge of the turbine bucket can be controlled independent of each other by separately positioning the leading edge core section and the trailing edge core section in the casting die. The controlled leading and trailing edge thicknesses can thus be optimized for efficient cooling, resulting in more efficient turbine operation.
Stathopoulos, Dimitrios (Glenmont, NY); Xu, Liming (Greenville, SC); Lewis, Doyle C. (Greer, SC)
Fetal abdominal wall repair with a collagen biomatrix in an experimental sheep model for gastroschisis
We evaluated the regeneration of the abdominal wall using a dual-layer collagen biomatrix, and the protective effect on the bowel of fetal abdominal wall repair in a fetal sheep model for gastroschisis. In 14 fetal lambs, the abdominal wall was opened at 79 days' gestation, creating a gastroschisis. In group 1, the gastroschisis was left uncovered. In group 2, the
Luc A. J. Roelofs; Alex J. Eggink; Christina A. Hulsbergen-van de Kaa; Paul P. van den Berg; A. H. M. S. M. van Kuppevelt; Herman T. B. van Moerkerk; A. Jane Crevels; Fred K. Lotgering; Wout F. J. Feitz; Rene M. H. Wijnen
Hydatid cysts in abdominal wall and ovary in a case of diffuse abdominal hydatidosis: Imaging and pathological correlation
We report a case of diffuse abdominal hydatidosis with correlation of imaging findings with gross pathology. The patient had involvement of liver, diaphragm, pelvic cavity, ovary and abdominal wall. Hydatid cysts were morphologically different from each other including calcified, uniloculated and multiloculated cystic lesions. Our case is rare as ovary and abdominal wall involvement is described in less than 1 % cases of hydatid disease. PMID:22470661
Amin, Muhammad Umar; Mahmood, Rabia; Manzoor, Shahid; Ahmad, Shoib
Quantitative anatomical labeling of the anterior abdominal wall
NASA Astrophysics Data System (ADS)
Ventral hernias (VHs) are abnormal openings in the anterior abdominal wall that are common side effects of surgical intervention. Repair of VHs is the most commonly performed procedure by general surgeons worldwide, but VH repair outcomes are not particularly encouraging (with recurrence rates up to 43%). A variety of open and laparoscopic techniques are available for hernia repair, and the specific technique used is ultimately driven by surgeon preference and experience. Despite routine acquisition of computed tomography (CT) for VH patients, little quantitative information is available on which to guide selection of a particular approach and/or optimize patient-specific treatment. From anecdotal interviews, the success of VH repair procedures correlates with hernia size, location, and involvement of secondary structures. Herein, we propose an image labeling protocol to segment the anterior abdominal area to provide a geometric basis with which to derive biomarkers and evaluate treatment efficacy. Based on routine clinical CT data, we are able to identify inner and outer surfaces of the abdominal walls and the herniated volume. This is the first formal presentation of a protocol to quantify these structures on abdominal CT. The intra- and inter rater reproducibilities of this protocol are evaluated on 4 patients with suspected VH (3 patients were ultimately diagnosed with VH while 1 was not). Mean surfaces distances of less than 2mm were achieved for all structures.
Allen, Wade M.; Xu, Zhoubing; Asman, Andrew J.; Poulose, Benjamin K.; Landman, Bennett A.
Abdominal Wall Abscess Formation Two Years After Laparoscopic Cholecystectomy
Background: Spillage of gallstones within the subcutaneous tissue during laparoscopic cholecystecomy may lead to considerable morbidity. Methods: We describe an abdominal wall abscess formation in a 50-year-old female that developed 24 months after a laparoscopic cholecystectomy. Results: Spilled gallstones at the umbilical port site went undetected. Subsequently, an umbilical port-site abscess formed and was treated 2 years later. Conclusion: Any patient with a foreign body in the subcutaneous tissues after a laparoscopic cholecystectomy should be considered to have a retained stone. Use careful dissection, copious irrigation, and a retrieval device to avoid stone spillage. If spillage does occurs, percutaneous drainage and antibiotics followed by open retrieval of the stones should achieve adequate results during those delayed presentations of abdominal wall abscesses. PMID:16709372
Hand, Andy A.; Self, Michael L.
Abdominal Wall Synovial Sarcoma During Pregnancy-a Case Report.
Synovial sarcoma is rare, aggressive, malignant mesenchymal neoplasm. The recent literature does not validate its only prevalence in the extremities of the adult population. Statistics reveal that adult population has the highest prevalence rate; 30Ā% of reported cases occur in the children and adolescents. It is very rare in pregnancy. Carcinomas may be diagnosed concurrently with pregnancy in approximately 0.1Ā% of cases, but sarcomas are rare. We report a 21-year-old woman with synovial sarcoma on anterior abdominal wall at 34th week of gestation, which was clinically diagnosed as desmoid tumor. Tumor was totally excised. After 6Āmonths, it relapsed in the form of multiple abdominal wall swellings and ascites. PMID:24426649
Kanade, Umesh S; Gadgil, Pradeep A; Birare, Shivaji D; Chaware, Suresh A; Kamra, Hemlata
Postoperative necrotizing soft-tissue infections of the abdominal wall
Objective: The aim of the underlying study was the evaluation of an aggressive surgical regimen for treatment of postoperative necrotizing\\u000a soft-tissue infection (NSTI). Methods: Eight patients with postoperative NSTI of the abdominal wall after emergency (n=6) and elective (n=2) surgery were reviewed over a 9-year period. Results: Initially, three patients presented with general peritonitis. Cultured swabs from the necrotic tissue
P. Bertram; K.-H. Treutner; M. Stumpf; V. Schumpelick
Experimental abdominal wall defect repaired with acellular matrix
In the surgical repair of congenital abdominal-wall defects (AWD), the ready availability of a non-immunogenic and non-prosthetic biomaterial that could guide the regeneration of normal tissue is a fascinating possibility. Biomaterials are already in use, but in our experience, an acellular matrix (ACM) can stimulate exact regeneration of the absent tissue. We explored the possibility of using an ACM to
P. Gamba; M. Conconi; R. Lo Piccolo; G. Zara; R. Spinazzi; P. Parnigotto
Postoperative fistula of the abdominal wall after laparascopic cholecystectomy due to lost gallstones
Abdominal fistula caused by cholesterol gallstones, which remained in the abdominal wall after laparascopic cholecystectomy: a laparascopic cholecystectomy was performed in a 60-years-old man who was diagnosed as acute necrosing cholecystitis due to cholecystolithiasis. After removal of the gallbladder using an Endocath some gallstones remained in the excision channel of the abdominal wall. Therefore, a fistula developed in the excision
H. Weiler; A. Grandel
Wall shear stress and endothelial cells dysfunction in the context of abdominal aortic aneurysms
Wall shear stress and endothelial cells dysfunction in the context of abdominal aortic aneurysms Z7342,13384 Marseille Keywords: wall shear stress, abdominal aortic aneurysm, endothelial cells, mechanotransduction 1. Introduction The formation of aneurysm of abdominal aorta (AAA), is a multi
Paris-Sud XI, Universitķ de
The Role of Geometric Parameters in the Prediction of Abdominal Aortic Aneurysm Wall Stress
The Role of Geometric Parameters in the Prediction of Abdominal Aortic Aneurysm Wall Stress E to diameter in differentiating patients with abdominal aortic aneurysms (AAAs), who will experience wall stress (PWS) and abdominal aorta aneurysm (AAA) geometric parameters in the presence
Papaharilaou, Yannis
Distribution of Wall Stress in Abdominal Aortic Aneurysm (AAA)
NASA Astrophysics Data System (ADS)
Abdominal aortic aneurysm (AAA) rupture is believed to occur when the mechanical stress acting on the wall exceeds the strength of the wall tissue. Therefore, knowledge of the AAA wall stress distribution could be useful in assessing its risk of rupture. In our research, a finite element analysis was used to determine the wall stresses both in idealized models and in a real clinical model in which the aorta was considered isotropic with nonlinear material properties and was loaded with a given pressure. In the idealized models, both maximum diameter and asymmetry were found to have substantial influence on the distribution of the wall stress. The thrombus inside the AAA was also found to help protecting the walls from high stresses. Using CT scans of the AAA, the actual geometry of the aneurysm was reconstructed and we found that wall tension increases on the flatter surface (typically corresponds to the posterior surface) and at the inflection points of the bulge. In addition to the static analysis, we also performed simulations of the effect of unsteady pressure wave propagation inside the aneurysm.
Lasheras, Juan
Effects of the flexibility of the arterial wall on the wall shear stresses and wall tension in Abdominal Aortic Aneurysms.
NASA Astrophysics Data System (ADS)
As an abdominal aortic aneurysm develops, large changes occur in the composition and structure of the arterial wall, which result in its stiffening. So far, most studies, whether experimental or numerical, have been conducted assuming the walls to be rigid. A numerical simulation of the fluid structure interactions is performed in different models of aneurysms in order to analyze the effects that the wall compliance might have on the flow topology. Both symmetric and non-symmetric models of aneurysms are considered, all idealistic in shape. The wall mechanical properties are varied in order to simulate the progressive stiffening of the walls. The spatial and temporal distributions of wall tension are calculated for the different values of the wall elasticity and compared to the results for the rigid walls. In the case of rigid walls, the calculation of the wall shear stresses and pressure compare very well with experimental results.
Salsac, Anne-Virginie; Fernandez, Miguel; Chomaz, Jean-Marc
Tissue Expander Capsule for Abdominal Wall in Autologous Breast Reconstruction
Summary: Adjuvant treatment planning can change after breast cancer resection and definitive pathological examination. Radiation therapy is often chosen as a supplementary treatment. Rectus abdominis¢based muscle flaps are one of the main choices when breast reconstruction plans must be changed from implant-based to autologous methods. We herein report a case in which the patientÆs own tissue expander capsule was used to repair an abdominal wall defect after muscle-sparing transverse rectus abdominis myocutaneous flap reconstruction. PMID:25506530
Webster, Ronaldo Scholze; Netto, Rafael; de Araujo, Thiago Bozzi; Ely, Pedro Bins
Evaluation of Enzymes Involved in Proteoglycan Degradation in the Wall of Abdominal Aortic Aneurysms
The abdominal aortic aneurysm (AAA) wall represents an extreme example of arterial remodeling with disturbed elastin, collagen and proteoglycan metabolism. The aim of this study was to evaluate enzymes involved in the degradation of glycosaminoglycan chains and core proteins of proteoglycans in the AAA wall. The study material consisted of wall samples from 10 AAA. Fragments of 5 normal abdominal
Krzysztof Sobolewski; Marek Gacko
Wall thickness design and corrosion management
In 1995, Norske Shell will install two 36-in. sweet wet gas pipe lines in the Norwegian sector of the North Sea. The lines cross the Norwegian trench with water depths up to 350 meter. For the last 3.5 km. of the route the pipelines will be laid in a tunnel which will be flooded after construction. The two lines will transport largely untreated well fluids from the Troll field to an onshore processing plant at Kollsness, North of Bergen. From there sales gas will be transported to the continent via the Furopipe and Zeepipe systems. Gas contracts covering 30 years have been concluded with gas utilities on the continent. The maximum wall thickness that could be installed was limited by the capabilities of the present generation of lay barges and pipe mill capacities. The over-thickness, i.e. beyond that what is required for pressure containment and external collapse, is available as corrosion allowance. The paper discusses a novel probabilistic approach to define the corrosion control measures. The corrosion control system is based on the injection of glycol for corrosion mitigation and inspection by ultrasonic internal smart pigs, which in combination with identified fall back options, ensure a minimum 50 year service life.
Gestel, W.M. van; Guijt, J. [A/S Norske Shell, Sandsli (Norway). Troll Project
Changes in wall shear stresses in abdominal aortic aneurysms with increasing wall stiffness
NASA Astrophysics Data System (ADS)
During the growth of abdominal aortic aneurysms, local changes occur in the composition and structure of the diseased wall, resulting in its stiffening. A numerical simulation of the fluid structure interactions is performed in idealized models of aneurysms using a finite element method. A full coupling of the equations governing the pulsatile blood flow and the deformation of the compliant wall is undertaken. The effect of the progressive stiffening of the wall is analyzed at various stages in the growth of the aneurysm. Increasing the wall stiffness alters the distribution of wall shear stresses and leads to an increase in their magnitude. The wall compliance is shown to have a more pronounced effect on non-axisymmetric aneurysms, which sustain large displacements. The overall movement of the aneurysm models increases the three-dimensionality of the flow.
Salsac, Anne-Virginie; Fernandez, Miguel
Domain walls of finite thickness in general relativity
The case of a domain wall of finite thickness is examined by use of two different expressions for the energy-stress tensor of domain walls but no symmetry condition. It is found that the equations of general relativity show that such walls cannot be in static equilibrium, and further even nonequilibrium walls can be consistent with Einstein's equations only under very special circumstances.
Raychaudhuri, A.K.; Mukherjee, G.
Effect of intraluminal thrombus on wall stress in patient-specific models of abdominal aortic aneurysm
Purpose: The role of intraluminal thrombus (ILT) on abdominal aortic aneurysm rupture is still not clear. Rupture of an aneurysm occurs when the wall stress exceeds the wall strength at any location on the wall. The purpose of this study was to address the hypothesis that the presence of ILT alters the wall stress distribution or wall stress magnitude in
David H. J. Wang; Michel S. Makaroun; Marshall W. Webster; David A. Vorp
Histopathological reaction of the abdominal aorta wall to non-covered stents
Objective: To evaluate the histopathological reaction of the abdominal aorta wall in pigs' renal arteries to the presence of non-covered stainless steel stents. Methods: The abdominal aorta of ten pigs (6 months old and weighing 86.6 kg on average) was histopathologically studied 100 days after the implant of stainless steel stents in the abdominal aorta, with one segment of the
Rubio Bombonato; Josķ Hon¾rio PALMA; Josķ Augusto MARCONDES; Aury Nunes de MORAES; JoŃo Luiz da ROCHA; Mßrcio Rodrigo; Rodrigo Mezzalira; Enio Buffolo
Thick domain walls in a polynomial approximation
Relativistic domain walls are studied in the framework of a polynomial ap- proximation to the field interpolating between different vacua and forming the domain wall. In this approach we can calculate evolution of a core and of a width of the domain wall. In the single, cubic polynomial approximation used in this paper, the core obeys Nambu-Goto equation for a
H. Arodz
Thick domain walls in a polynomial approximation
Relativistic domain walls are studied in the framework of a polynomial approximation to the field interpolating between different vacua and forming the domain wall. In this approach we can calculate the evolution of a core and of a width of the domain wall. In the single cubic polynomial approximation used in this paper, the core obeys the Nambu-Goto equation for
H. Arodz
Spontaneous intraamniotic hemorrhage in the second trimester mimicking an abdominal wall defect
We report here a case of spontaneous intraamniotic haemorrhage in the second trimester which mimicked an abdominal wall defect. The ultrasound and magnetic resonance imaging findings are discussed and a review of the literature regarding differential diagnosis of bleeding and abdominal wall defects is made. PMID:24592085
▄st³ner, I??k; G³ven, Emine Seda G³venda?; Bal?k, G³l?ah; ?ent³rk, ?enol; ▄st³ner, Evren; Atman, Ebru D³?³nceli; Av?ar, Ay?e Filiz
Effects of the loss of symmetry on the wall shear stresses in Abdominal Aortic Aneurysms
the method described in Chapter 2. C. Results 1. Flow characteristics in abdominal aortic aneurysms Flow75 Chapter 4 Effects of the loss of symmetry on the wall shear stresses in Abdominal Aortic Aneurysms A. Introduction Owing to their effect on the endothelial cells, wall shear stresses appear
An Abdominal Aorta Wall Extraction for Liver Cirrhosis Classification Using Ultrasonic Images
NASA Astrophysics Data System (ADS)
We propose a method to extract an abdominal aorta wall from an M-mode image. Furthermore, we propose the use of a Gaussian filter in order to improve image quality. The experimental results show that the Gaussian filter is effective in the abdominal aorta wall extraction.
Hayashi, Takaya; Fujita, Yusuke; Mitani, Yoshihiro; Hamamoto, Yoshihiko; Segawa, Makoto; Terai, Shuji; Sakaida, Isao
Effects of Inhalatory Abdominal Wall Movement on Vertical Laryngeal Position During Phonation
The configuration of the body resulting from inhalatory behavior is sometimes considered a factor of relevance to voice production in singing and speaking pedagogy and in clinical voice therapy. The present investigation compares two different inhalatory behaviors: (1) with a ōparadoxicalö inward movement of the abdominal wall, and (2) with an expansion of the abdominal wall, both with regard to
Jenny Iwarsson
Thick domain walls in a polynomial approximation
Relativistic domain walls are studied in the framework of a polynomial approximation to the field interpolating between different vacua and forming the domain wall. In this approach we can calculate evolution of a core and of a width of the domain wall. In the single, cubic polynomial approximation used in this paper, the core obeys Nambu-Goto equation for a relativistic membrane. The width of the domain wall obeys a nonlinear equation which is solved perturbatively. There are two types of corrections to the constant zeroth order width: the ones oscillating in time, and the corrections directly related to curvature of the core. We find that curving a static domain wall is associated with an increase of its width. As an example, evolution of a toroidal domain wall is investigated.
Arodz, H
Thick domain walls in a polynomial approximation
NASA Astrophysics Data System (ADS)
Relativistic domain walls are studied in the framework of a polynomial approximation to the field interpolating between different vacua and forming the domain wall. In this approach we can calculate the evolution of a core and of a width of the domain wall. In the single cubic polynomial approximation used in this paper, the core obeys the Nambu-Goto equation for a relativistic membrane. The width of the domain wall obeys a nonlinear equation which is solved perturbatively. There are two types of corrections to the constant zeroth order width: the ones oscillating in time and the corrections directly related to the curvatuve of the core. We find that curving a static domain wall is associated with an increase of its width. As an example, the evolution of a toroidal domain wall is investigated.
Arod?, H.
Thick domain walls in a polynomial approximation
Relativistic domain walls are studied in the framework of a polynomial approximation to the field interpolating between different vacua and forming the domain wall. In this approach we can calculate evolution of a core and of a width of the domain wall. In the single, cubic polynomial approximation used in this paper, the core obeys Nambu-Goto equation for a relativistic membrane. The width of the domain wall obeys a nonlinear equation which is solved perturbatively. There are two types of corrections to the constant zeroth order width: the ones oscillating in time, and the corrections directly related to curvature of the core. We find that curving a static domain wall is associated with an increase of its width. As an example, evolution of a toroidal domain wall is investigated.
H. Arodz
Wall stress distribution on three-dimensionally reconstructed models of human abdominal aortic aneurysm
Purpose: Abdominal aortic aneurysm (AAA) rupture is believed to occur when the mechanical stress acting on the wall exceeds the strength of the wall tissue. Therefore, knowledge of the stress distribution in an intact AAA wall could be useful in assessing its risk of rupture. We developed a methodology to noninvasively estimate the in vivo wall stress distribution for actual
M. L Raghavan; David A Vorp; Michael P Federle; Michel S Makaroun; Marshall W Webster
Contribution of the skin, rectus abdominis and their sheaths to the structural response of the abdominal wall ex vivo.
A better understanding of the abdominal wall biomechanics could help designing new treatments for incisional hernia. In the current study, an experimental protocol was developed to evaluate the contributions of the abdominal wall components to the structural response of the anterior part of the abdominal wall. The specimens underwent 3 dissections (removal of (1) skin and subcutaneous fat, (2) anterior rectus sheath, (3) rectus abdominis muscles). After each dissection, they were subjected to air pressure up to 3 kPa. Ultrasound images and associated elastographic maps were collected at 0, 2 and 3 kPa in the intact state and strains on the internal surface were calculated using stereo-correlation in all states. Strains on the rectus abdominis and linea alba were analyzed. After the dissection of the anterior sheath of the rectus abdominis, longitudinal strain was found significantly different on the linea alba (5% at 3 kPa) and on the rectus abdominis area (11% at 3 kPa). The current results highlight the importance of the rectus sheath in the structural response of the anterior part of the abdominal wall ex vivo. Geometrical characteristics such as thicknesses and radii of curvature and mechanical properties (shear modulus of the rectus abdominis, e.g. at 0 pressure the average value is 14 kPa) were provided in order to facilitate future modeling efforts. PMID:25065730
Tran, D; Mitton, D; Voirin, D; Turquier, F; Beillas, P
Progressive Increase of Bowel Wall Thickness Is a Reliable Indicator for Surgery in Patients With Adhesive Small Bowel Obstruction
PURPOSE: The aim of this study was to determine whether progressive increase of bowel wall thickness during nonoperative treatment is a reliable indicator for surgery in patients with adhesive small bowel obstruction. METHODS: The study consisted of a prospective case series of 121 patients with adhesive small bowel obstruction who underwent an abdominal ultrasonographic examination. The results of ultrasonographic examinations
Shyr-Chyr Chen; Chien-Chang Lee; Chiung-Yuan Hsu; Zui-Shen Yen; Cheng-Chung Fang; Matthew H.-M. Ma; Wen-Jone Chen; Hong-Shiee Lai; Po-Huang Lee; Fang-Yue Lin; Wei-Jao Chen
Distribution of Early Atherosclerotic Lesions in the Human Abdominal Aorta Correlates with Wall Shear Stresses Measured In Vivo
Objectives: to study the relationship between wall shear stresses measured in vivo and early atherosclerotic lesions in the abdominal aorta. Materials: eight young volunteers for in vivo wall shear-stress measurements. Abdominal aortas from 10 young adults without signs or history of atherosclerotic disease were obtained by autopsy for histomorphometric measurements. Methods: wall shear stresses were measured in the abdominal aorta
E. M Pedersen; S Oyre; M Agerbµk; I. B Kristensen; S Ringgaard; P Boesiger; W. P Paaske
Rectus Abdominis Muscle Malignant Fibrous Histiocytoma Causing a Large Abdominal Wall Defect: Reconstruction with Biological Mesh
Malignant fibrous histiocytoma (MFH) is a common soft tissue sarcoma usually involving limbs and retroperitoneum. MFH of the rectus abdominis muscle is extremely rare. Surgery in similar cases leads to large abdominal wall defects needing reconstruction. Biological and synthetic laminar absorbable prostheses are available for the repair of hernia defects in the abdominal wall. They share the important feature of being gradually degraded in the host, resulting the formation of a neotissue. We herein report the case of an 84-year-old man with MFH of the rectus abdominis muscle which was resected and the large abdominal wall defect was successfully repaired with a biological mesh. PMID:24653854
Falidas, Evangelos; Gourgiotis, Stavros; Goudeli, Christina; Mathioulakis, Stavros; Villias, Constantinos
Mechanical wall stress in abdominal aortic aneurysm: Influence of diameter and asymmetry
Purpose: Risk for rupture of an abdominal aortic aneurysm is widely believed to be related to its maximum diameter. From a biomechanical standpoint, however, risk is probably more precisely related to mechanical wall stress. Many abdominal aortic aneurysms are asymmetric (for example because of anterior bulging with posterior expansion limited by the vertebral column). The purpose of this work was
David A. Vorp; M. L. Raghavan; Marshall W. Webster
Architectural and morphological assessment of rat abdominal wall muscles: comparison for use as a human model
The abdominal wall is a composite of muscles that are important for the mechanical stability of the spine and pelvis. Tremendous clinical attention is given to these muscles, yet little is known about how they function in isolation or how they interact with one another. Given the morphological, vascular, and innervation complexities associated with these muscles and their proximity to the internal organs, an appropriate animal model is important for understanding their physiological and mechanical significance during function. To determine the extent to which the rat abdominal wall resembles that of human, 10 adult male Sprague-Dawley rats were killed and formalin-fixed for architectural and morphological analyses of the four abdominal wall muscles (rectus abdominis, external oblique, internal oblique, and transversus abdominis). Physiological cross-sectional areas and optimal fascicle lengths demonstrated a pattern that was similar to human abdominal wall muscles. In addition, sarcomere lengths measured in the neutral spine posture were similar to human in their relation to optimal sarcomere length. These data indicate that the force-generating and length change capabilities of these muscles, relative to one another, are similar in rat and human. Finally, the fiber lines of action of each abdominal muscle were similar to human over most of the abdominal wall. The main exception was in the lower abdominal region (inferior to the pelvic crest), where the external oblique becomes aponeurotic in human but continues as muscle fibers into its pelvic insertion in the rat. We conclude that, based on the morphology and architecture of the abdominal wall muscles, the adult male Sprague-Dawley rat is a good candidate for a model representation of human, particularly in the middle and upper abdominal wall regions. PMID:20646108
Brown, Stephen H M; Banuelos, Karina; Ward, Samuel R; Lieber, Richard L
Abdominal wall desmoid tumors: A proposal for US-guided resection
Background Desmoid tumors (DTs) is a benign tumor with high tendency to infiltrative evolution and recurrence. Nowadays, in abdominal localization, the standard approach is surgery with R0 condition. The need to repair post-surgical wide wall defect requires conservative technique to decrease the incidence of incisional hernia and to obtain better quality of life (QoL). Methods We perform an abdominal wall desmoid resection using ultrasound guide. This technique ensures to spare a wide wall area and to obtain a multilayer reconstruction minimizing postoperative risk. This approach allows good oncological results and better managing abdominal wall post-resection defect. Results We use US guided surgery to get radical approach and wall tissue spare that allows us a multilayer reconstruction minimizing post-operative complications. No recurrences were observed in one year follow up period. Conclusion Our experience represents first step to consider ultrasound mediated technique usefull to optimize wall resection surgery and to minimize following complications. PMID:25706804
Bolzon, Stefano; Vagliasindi, Alessio; Zanzi, Federico; Negri, Marco; Guerrini, Gian Piero; Rossi, Camilla; Soliani, Paolo
49 CFR 192.109 - Nominal wall thickness (t) for steel pipe.
Code of Federal Regulations, 2011 CFR
... false Nominal wall thickness (t) for steel pipe. 192.109 Section 192.109 Transportation...109 Nominal wall thickness (t ) for steel pipe. (a) If the nominal wall thickness for steel pipe is not known, it is determined...
49 CFR 192.109 - Nominal wall thickness (t) for steel pipe.
Code of Federal Regulations, 2013 CFR
... false Nominal wall thickness (t) for steel pipe. 192.109 Section 192.109 Transportation...109 Nominal wall thickness (t ) for steel pipe. (a) If the nominal wall thickness for steel pipe is not known, it is determined...
49 CFR 192.109 - Nominal wall thickness (t) for steel pipe.
Code of Federal Regulations, 2012 CFR
... false Nominal wall thickness (t) for steel pipe. 192.109 Section 192.109 Transportation...109 Nominal wall thickness (t ) for steel pipe. (a) If the nominal wall thickness for steel pipe is not known, it is determined...
49 CFR 192.109 - Nominal wall thickness (t) for steel pipe.
Code of Federal Regulations, 2014 CFR
... false Nominal wall thickness (t) for steel pipe. 192.109 Section 192.109 Transportation...109 Nominal wall thickness (t ) for steel pipe. (a) If the nominal wall thickness for steel pipe is not known, it is determined...
Bladder wall thickness mapping for magnetic resonance cystography
NASA Astrophysics Data System (ADS)
Clinical studies have shown evidence that the bladder wall thickness is an effective biomarker for bladder abnormalities. Clinical optical cystoscopy, the current gold standard, cannot show the wall thickness. The use of ultrasound by experts may generate some local thickness information, but the information is limited in field-of-view and is user dependent. Recent advances in magnetic resonance (MR) imaging technologies lead MR-based virtual cystoscopy or MR cystography toward a potential alternative to map the wall thickness for the entire bladder. From a high-resolution structural MR volumetric image of the abdomen, a reasonable segmentation of the inner and outer borders of the bladder wall can be achievable. Starting from here, this paper reviews the limitation of a previous distance field-based approach of measuring the thickness between the two borders and then provides a solution to overcome the limitation by an electric field-based strategy. In addition, this paper further investigates a surface-fitting strategy to minimize the discretization errors on the voxel-like borders and facilitate the thickness mapping on the three-dimensional patient-specific bladder model. The presented thickness calculation and mapping were tested on both phantom and human subject datasets. The results are preliminary but very promising with a noticeable improvement over the previous distance field-based approach.
Zhao, Yang; Liang, Zhengrong; Zhu, Hongbin; Han, Hao; Duan, Chaijie; Yan, Zengmin; Lu, Hongbing; Gu, Xianfeng
Bladder Wall Thickness Mapping for Magnetic Resonance Cystography
Clinical studies have shown the evidence that the bladder wall thickness is an effective biomarker for bladder abnormalities. The clinical optical cystoscopy, the current gold standard, cannot show the wall thickness. The use of ultrasound by experts may generate some local thickness information, but the information is limited in field-of-view and is user dependent. Recent advances in magnetic resonance (MR) imaging technologies lead MR-based virtual cystoscopy or MR cystography toward a potential alternative to map the wall thickness for the entire bladder. From a high resolution structural MR volumetric image of the abdomen, a reasonable segmentation of the inner and outer borders of the bladder wall can be achievable. Starting from here, this paper reviews the limitation of a previous distance field-based approach of measuring the thickness between the two borders and then provides a solution to overcome the limitation by an electric field-based strategy. In addition, this paper further investigates a surface fitting strategy to minimize the discretization errors on the voxel-like borders and facilitate the thickness mapping on the three-dimensional patient-specific bladder model. The presented thickness calculation and mapping were tested on both phantom and human subject datasets. The results are preliminary but very promising with a noticeable improvement over the previous distance field-based approach. PMID:23835844
Zhao, Yang; Liang, Zhengrong; Zhu, Hongbin; Han, Hao; Duan, Chaijie; Yan, Zengmin; Lu, Hongbing; Gu, Xianfeng
The effect of abdominal wall plication on intra-abdominal pressure and lower extremity venous flow: a case report.
Abdominal wall plication is known to cause increased intra-abdominal pressure (IAP). Whether plication-associated increased IAP causes lower extremity venous stasis, a recognized risk factor for DVT, remains unknown. A 55-year-old woman had a unilateral pedicled TRAM procedure for mastectomy reconstruction. Prior to plication, duplex ultrasound measured proximal femoral vein (PFV) cross-sectional diameter and volume-flow. PFV measurements were repeated immediately after plication and on post-operative days (POD) 1, 2, and 4. Bladder pressure was measured at similar timepoints. PFV volume-flow decreased from 0.22 L/min to 0.16 L/min (73% of baseline) immediately post-plication and reached a nadir of 0.08 L/min (36% of baseline) on POD 2. Bladder pressure increased from 13 mm Hg to 19 mm Hg after plication, and peaked at 31 mm Hg after intra-operative trunk flexion to 30░. Thus, abdominal wall plication was associated with increased intra-abdominal pressure and ultrasound-documented lower extremity venous stasis that persisted for 48 h after surgery. PMID:21855437
Pannucci, Christopher J; Alderman, Amy K; Brown, Sandra L; Wakefield, Thomas W; Wilkins, Edwin G
One-Stage Reconstruction of Large Midline Abdominal Wall Defects Using a Composite Free Anterolateral Thigh Flap With Vascularized Fascia Lata
Objective: Large midline abdominal wall defects are continuously a challenge for reconstructive surgeons. Adequate skin coverage and fascia repair of the abdominal wall is necessary for achieving acceptable results. The purpose of this paper is to present a new approach to abdominal wall reconstruction using a free vascularized composite anterolateral thigh (ALT) flap with fascia lata. Methods: Seven patients with large full-thickness abdominal wall defects were successfully reconstructed by means of a composite ALT flap combined with vascularized fascia lata. The size of the skin islands ranged from 20 to 32 cm in length and 10 to 22 cm in width, and the vascularized fascia lata sheath measured 14 to 28 cm and 8 to 18 cm, respectively. Functional outcome of the abdominal wall strength and donor thigh morbidity were investigated by using a Cybex kinetic dynamometer. Results: All flaps survived. No postoperative ventral hernia occurred except for one mild inguinal incision hernia. Subjectively there were no significant donor site problems. Objective assessment was performed in 4 patients 2 years postoperatively. In the reconstructed abdomen, isokinetic concentric and eccentric measurements of extension/flexion ratios of the abdominal wall strength showed no apparent decrease compared with other references. Functional evaluation of quadriceps femoris muscle contraction forces after free ALT composite flap harvest showed an averaged deficit of 30% as compared with the contralateral legs. However, no difficulties in daily ambulating were reported by the patients. Conclusion: The free composite ALT myocutaneous flap with vascularized fascia lata provides an alternative option for a stable repair in complex abdominal wall defects. PMID:15075651
Kuo, Yur-Ren; Kuo, Mei-Hui; Lutz, Barbara S.; Huang, Yu-Chi; Liu, Yi-Tien; Wu, Shih-Chi; Hsieh, Kun-Chou; Hsien, Ching-Hua; Jeng, Seng-Feng
Gear-shift lever having variable thickness walls
A one-piece elongated tubular transmission gear shift lever, is described comprising a tubular connector part at a first end of the gear shift lever, whereby the tubular connector part is adapted to be secured to a pivot means; a spherical part extending from the connector part, the connector part and the spherical part having a first wall thickness; a cylindrical part extending from the spherical part in a direction opposite the tubular connector part, the cylindrical part having a second wall thickness less than the first wall thickness; a tapered part extending from the cylindrical part; and a threaded part extending from the tapered part, the threaded part formed at a second end of the gear shift lever opposite the first end, whereby a gear shift knob may be attached.
Tanaka, T.
Intra-abdominal pressure and abdominal wall muscular function: spinal unloading mechanism
BACKGROUND The roles of antagonistic activation of abdominal muscles and of intra-abdominal pressurization remain enigmatic, but are thought to be associated with both spinal unloading and spinal stabilization in activities such as lifting. Biomechanical analyses are needed to understand the function of intra-abdominal pressurization because of the anatomical and physiological complexity, but prior analyses have been over-simplified. METHODS To test whether increased intra-abdominal pressure was associated with reduced spinal compression forces for efforts that generated moments about each of the principal axis directions, a previously published biomechanical model of the spine and its musculature was modified by the addition of anatomically realistic three-layers of curved abdominal musculature connected by fascia to the spine. Published values of muscle cross-sectional areas and the active and passive stiffness properties were assigned. The muscle activations were calculated assuming minimized muscle stress and stretch for the model loaded with flexion, extension, lateral bending and axial rotation moments of up to 60 Nm, along with intra-abdominal pressurization of 5 or 10 kPa (37.5 or 75 mmHg) and partial bodyweight (340 N). FINDINGS The analysis predicted a reduction in spinal compressive force with increase in intra-abdominal pressurization from 5 to 10 kPa. This reduction at 60 Nm external effort was 21% for extension effort, 18% for flexion effort, 29% for lateral bending and 31% for axial rotation. INTERPRETATION This analysis predicts that intra-abdominal pressure produces spinal unloading, and shows likely muscle activation patterns that achieve this. PMID:20655636
Stokes, Ian A.F.; Gardner-Morse, Mack G.; Henry, Sharon M.
In vivo analysis of mechanical wall stress and abdominal aortic aneurysm rupture risk
Objective: The purpose of this study was to calculate abdominal aortic aneurysm (AAA) wall stresses in vivo for ruptured, symptomatic, and electively repaired AAAs with three-dimensional computer modeling techniques, computed tomographic scan data, and blood pressure and to compare wall stress with current clinical indices related to rupture risk. Methods: CT scans were analyzed for 48 patients with AAAs: 18
Mark F. Fillinger; M. L. Raghavan; Steven P. Marra; Jack L. Cronenwett; Francis E. Kennedy
Association of intraluminal thrombus in abdominal aortic aneurysm with local hypoxia and wall weakening
Purpose: Our previous computer models suggested that intraluminal thrombus (ILT) within an abdominal aortic aneurysm (AAA) attenuates oxygen diffusion to the AAA wall, possibly causing localized hypoxia and contributing to wall weakening. The purpose of this work was to investigate this possibility. Methods: In one arm of this study, patients with AAA were placed in one of two groups: (1)
David A. Vorp; Paul C. Lee; David H. J. Wang; Michel S. Makaroun; Edwin M. Nemoto; Satoshi Ogawa; Marshall W. Webster
[Resection of malignant fibrous histiocytoma through a combined thoracic and abdominal wall approach].
We report a case of resection of malignant fibrous histiocytoma (MFH) via combined thoracic and abdominal wall incision reconstructed using GORE DUALMESH. A 60-year-old woman underwent resection of a left lower chest wall tumor. Since the tumor infiltrated into the diaphragm, a part of the left diaphragm and left upper abdominal wall were resected together. The left chest was closed by suturing the diaphragm to the ribs. The resected area of the thoracic and abdominal wall was 12ū12 cm and was reconstructed with GORE DUALMESH. She received adjuvant radiotherapy as the tumor cells were detected in the surgical margin of the diaphragm. The patient has remained well without signs of recurrence for 10 months after the operation. PMID:22569497
Otsuka, T; Harada, A; Wakida, K; Aoki, M; Nagata, T; Kariatsumari, K; Sakasegawa, K; Nakamura, Y; Sato, M; Nakayama, H; Kitajima, S
Cold Abscess of the Anterior Abdominal Wall: An Unusual Primary Presentation
Tuberculosis is considered as ubiquitous disease as it involves any organ, but primary involvement of abdominal muscles is very rare. In most cases, the muscle involvement is secondary and is caused by either hematogenous route or direct inoculation from a tuberculous abdominal lymph node or extension from underlying tubercular synovitis and osteomyelitis. Autopsy studies have shown abdominal wall involvement in less than 1% of patients who died of tuberculosis. Antitubercular therapy is main form of management. Surgical intervention is always secondary in the form of either sonography or computerized tomography-guided aspiration or open drainage which is usually reserved for patients in whom medical treatment has failed. A case is hereby reported about primary tubercular anterior abdominal wall abscess without any evidence of pulmonary, skeletal or gastrointestinal tuberculosis in an apparently healthy individual with any past history of contact or previous antituberculosis therapy. PMID:24027388
Malhotra, Mohinder Kumar
Cold abscess of the anterior abdominal wall: an unusual primary presentation.
Tuberculosis is considered as ubiquitous disease as it involves any organ, but primary involvement of abdominal muscles is very rare. In most cases, the muscle involvement is secondary and is caused by either hematogenous route or direct inoculation from a tuberculous abdominal lymph node or extension from underlying tubercular synovitis and osteomyelitis. Autopsy studies have shown abdominal wall involvement in less than 1% of patients who died of tuberculosis. Antitubercular therapy is main form of management. Surgical intervention is always secondary in the form of either sonography or computerized tomography-guided aspiration or open drainage which is usually reserved for patients in whom medical treatment has failed. A case is hereby reported about primary tubercular anterior abdominal wall abscess without any evidence of pulmonary, skeletal or gastrointestinal tuberculosis in an apparently healthy individual with any past history of contact or previous antituberculosis therapy. PMID:24027388
Malhotra, Mohinder Kumar
Improving laparoscopy in embalmed cadavers: a new method with a lateral abdominal wall muscle section
Background Rigor mortis can be a problem when laparoscopy is performed in embalmed cadavers for surgical training. Methods To improve the laparoscopic view, a new technique for managing the abdominal wall with a cutaneous¢subcutaneous flap, pneumoperitoneum (14¢15ĀmmHg), and a progressive (step-by-step) bilateral section of the lateral muscles of the abdomen was attempted in 10 embalmed cadavers. The degree of abdominal
J. Nebot-Cegarra; E. Macarulla-Sanz
Significance of preoperative ultrasound measurement of gallbladder wall thickness.
Evaluation of patients with signs and symptoms of biliary tract disease usually includes ultrasound assessment of the gallbladder. Does measurement of the thickness of the gallbladder wall yield any significant information to the clinical surgeon? The records of all my patients undergoing cholecystectomy since 1990 were reviewed. The entire series consists of 401 consecutive patients, in whom 388 procedures were completed laparoscopically, with 14 patients requiring conversion to an open cholecystectomy. Each patient's preoperative evaluation included a gallbladder ultrasound, which included measurement of the diameter of the gallbladder wall. The entire series of cholecystectomies was evaluated according to the ultrasound measured diameter of the gallbladder wall. A thin gallbladder wall was less than 3 mm in diameter. A thick gallbladder wall was 3 mm or greater in diameter. Of the 401 consecutive patients who underwent cholecystectomy for symptomatic gallbladder disease, 86 (21.5%) were removed laparoscopically for acalculous disease. Eleven per cent of patients with acalculous cholecystitis had acute cholecystitis and 89 per cent had chronic cholecystitis. Every patient with either a thin or thick gallbladder wall with acalculous cholecystitis had a successful laparoscopic cholecystectomy. Three-hundred fifteen patients had a laparoscopic cholecystectomy for calculous cholecystitis. In patients with calculous cholecystitis, 28.3 per cent had acute cholecystitis and 71.7 per cent had chronic cholecystitis. The gallbladder wall was found to be greater than 3 mm in 38 per cent of patients with acute calculous cholecystitis and greater than 3 mm in 41 per cent of patients with chronic calculous cholecystitis. One-hundred, forty-two patients, out of a series total of 401, had a gallbladder wall thickness greater than 3 mm by preoperative sonography and 14 of these patients (10%) required conversion to an open cholecystectomy. A preoperative gallbladder ultrasound evaluation for symptomatic cholecystitis, which documents a thick gallbladder wall (> or =3 mm) with calculi, is a clinical warning for the laparoscopic surgeon of the potential for a difficult laparoscopic cholecystectomy procedure which may require conversion to an open cholecystectomy procedure. PMID:17939429
Majeski, James
Texture analysis improves level set segmentation of the anterior abdominal wall
Purpose: The treatment of ventral hernias (VH) has been a challenging problem for medical care. Repair of these hernias is fraught with failure; recurrence rates ranging from 24% to 43% have been reported, even with the use of biocompatible mesh. Currently, computed tomography (CT) is used to guide intervention through expert, but qualitative, clinical judgments, notably, quantitative metrics based on image-processing are not used. The authors propose that image segmentation methods to capture the three-dimensional structure of the abdominal wall and its abnormalities will provide a foundation on which to measure geometric properties of hernias and surrounding tissues and, therefore, to optimize intervention.Methods: In this study with 20 clinically acquired CT scans on postoperative patients, the authors demonstrated a novel approach to geometric classification of the abdominal. The authorsÆ approach uses a texture analysis based on Gabor filters to extract feature vectors and follows a fuzzy c-means clustering method to estimate voxelwise probability memberships for eight clusters. The memberships estimated from the texture analysis are helpful to identify anatomical structures with inhomogeneous intensities. The membership was used to guide the level set evolution, as well as to derive an initial start close to the abdominal wall.Results: Segmentation results on abdominal walls were both quantitatively and qualitatively validated with surface errors based on manually labeled ground truth. Using texture, mean surface errors for the outer surface of the abdominal wall were less than 2 mm, with 91% of the outer surface less than 5 mm away from the manual tracings; errors were significantly greater (2¢5 mm) for methods that did not use the texture.Conclusions: The authorsÆ approach establishes a baseline for characterizing the abdominal wall for improving VH care. Inherent texture patterns in CT scans are helpful to the tissue classification, and texture analysis can improve the level set segmentation around the abdominal region.
Xu, Zhoubing [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 (United States)] [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 (United States); Allen, Wade M. [Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States)] [Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States); Baucom, Rebeccah B.; Poulose, Benjamin K. [General Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37235 (United States)] [General Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37235 (United States); Landman, Bennett A. [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 and Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States)] [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 and Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States)
Squamous Cell Carcinoma Arising from Abdominal Wall Defect Lesion Complicated with Cloacal Exstrophy
Summary: Cloacal exstrophy is an extremely rare congenital complex deformity that is associated with anterior abdominal wall defects, reflex and exposure of the cloaca (uninterrupted ureter and bowel), aproctia, a widely separated pubic bone, and defects or dysplasia of external genital organs. Here, we present the case of a 42-year-old man with squamous cell carcinoma arising from an abdominal wall defect complicated by cloacal exstrophy. He was successfully treated with excision of the skin lesion with the bowel and reconstruction using a pedicled anterolateral thigh flap combined with a tensor fasciae latae flap. To our knowledge, this is the first report of squamous cell carcinoma arising from an abdominal wall defect complicated by cloacal exstrophy.
Yokoo, Satoshi; Takaku, Yuki; Morita, Hiroki; Yasuda, Masato
Paediatric abdominal wall hernia following handlebar injury: should we diagnose more and operate less?
Traumatic abdominal wall hernia following handlebar injury can be easily missed and is thus underreported. A 12-year-old boy presented with handlebar injury to the left upper quadrant of his abdomen. Except for a localised swelling, thought to be related to a haematoma, he was haemodynamically stable. CT revealed an abdominal wall defect with herniating fat that was not evident clinically and was also missed on immediate ultrasound examination. As there were no associated injuries and the abdominal wall defect was small without any herniating bowel loops, masterly inactivity was observed. After 6?weeks, the swelling has disappeared completely and there is progressive reduction in the size of the defect. PMID:23606382
Upasani, Anand; Bouhadiba, Nordeen
Effects of comorbidities and implant reinforcement on outcomes after component reconstruction of the abdominal wall.
A series of patients undergoing component reconstruction of midline abdominal wall separations was analyzed to assess the effects of comorbidities and biological implant reinforcements on outcomes. Thirty-nine patients were identified as fitting the technical definition of component repairs and having at least 12 months of documented follow-up. This group of procedures had a 67% primary healing rate, 18% and 13% rate of major and minor complications, respectively, and a total of 90% successful reconstructions after secondary procedures. Variables assessed for outcome influences included etiology of the abdominal wall separation, obesity, diabetes, hypertension, and biological implant reinforcements, including absorbable mesh and biological implants. None of these factors significantly influenced outcome, although first time repairs and reinforced repairs had suggestively higher success rates. This data suggest that comorbidities do not influence outcomes of component abdominal wall repairs, and assessments of the problem and ongoing technical refinements of the procedure should be studied further. PMID:20395814
Varkarakis, George; Daniels, Justin; Coker, Karah; Oswald, Tanya; Schleich, Arno; Muskett, Alan; Akdemir, Orunc; Lineaweaver, William
Comparison of Abdominal Muscle Thickness with Vaginal Pressure Changes in Healthy Women
[Purpose] The purpose of this study was to verify the efficacy of a pelvic floor muscle exercise program by comparing subjectsÆ muscle thickness with changes in vaginal pressure. [Subjects] Two groups of female participants without a medical history of pelvic floor muscle dysfunction were evaluated. The mean age of Group I was 33.5?years and that of Group II was 49.69?years. [Methods] The participants were instructed to perform a pelvic floor muscle contraction. While measuring the vaginal pressure of the pelvic floor muscle, biofeedback was given on five levels, and the thicknesses of the transversus abdominis, external oblique, and internal oblique muscles were measured with ultrasound. [Results] The thickness of the transversus abdominis muscle was significantly increased at 30 cmH2O in Group I, and at 20 cmH2O in Group II. The thickness of the internal oblique abdominal muscle significantly increased at maximum contraction in Group II. [Conclusion] Different abdominal muscles contracted depending on vaginal pressure. The result may be used to create and implement an exercise program that effectively strengthens the pelvic floor muscles. PMID:24707099
Kim, Bo-In; Hwang-Bo, Gak; Kim, Ha-Roo
Invasive group A Streptococcus resulting in sepsis and abdominal wall abscess after adenotonsillectomy.
Systemic infectious complications following adenotonsillectomy are exceedingly rare. We describe an otherwise healthy 2-year-old patient who developed group A beta-hemolytic Streptococcus sepsis and presumptive scarlet fever 3 days after an uncomplicated adenotonsillectomy. After resolution of fever, rash, and discharge home on antibiotics, the patient returned on postoperative day 10 with an abdominal wall abscess. This is the first reported case of an abdominal wall abscess as a complication of adenotonsillectomy. This case demonstrates that an awareness of unexpected infectious complications of adenotonsillectomy should be a part of postsurgical management. Laryngoscope, 2014. PMID:25363250
Wilson, Paul F; Wannemuehler, Todd J; Matt, Bruce H
Does laparoscopy used in open exploration alleviate pain associated with chronic intractable abdominal wall neuralgia?
BackgroundĀĀThis study aimed to assess the efficacy of diagnostic laparoscopy and open exploration of trigger points (scar revision and\\u000a neurectomy) in the treatment of intractable chronic abdominal wall pain.\\u000a \\u000a \\u000a \\u000a MethodsĀĀThis prospective nonrandomized study enrolled 24 patients (21 women) with an average age of 59 ▒ 11 years. Abdominal wall\\u000a pain was diagnosed by excluding other causes of pain and using
H. Paajanen
Pilot study on objective measurement of abdominal wall strength in patients with ventral incisional hernia
BackgroundĀĀOutcomes after ventral incisional hernia (VIH) repair are measured by recurrence rate and subjective measures. No objective\\u000a metrics evaluate functional outcomes after abdominal wall reconstruction. This study aimed to develop testing of abdominal\\u000a wall strength (AWS) that could be validated as a useful metric.\\u000a \\u000a \\u000a \\u000a \\u000a MethodsĀĀData were prospectively collected during 9Āmonths from 35 patients. A total of 10 patients were evaluated
Michael Parker; Ross F. Goldberg; Maryane M. Dinkins; Horacio J. Asbun; C. Daniel Smith; Susanne Preissler; Steven P. Bowers
Abdominal wall non-clostridian gas cellulitis: a rare complication of a colostoma.
The authors report the case of a 69 year-old patient, with obesity, having a left colostomy that has been made for rectal cancer (12 years ago) and who developed a non-clostridian gascellulitis of the abdominal wall as a result of intraparietal traumatic tract perforation of the colostomy. The presence of the peristomal hernia favoured the posttraumatic injury of the colostomy. Repeated surgical inteventions and the antibiotic treatment determined a favourable evolution. Despite the wound contamination with excrement, transit stoma relocation was not necessary. Some clinical and therapeutic aspects of abdominal wall infections are presented. PMID:25375062
Maier, A; Boieriu, L
Necrotizing fasciitis of the abdominal wall with lethal outcome: a case report.
Necrotizing fasciitis is an acute surgical condition that demands prompt and multi-faceted treatment. Early recognition, aggressive surgical debridement, and targeted antibiotic therapy significantly affect the overall course of treatment and survival. The author reports here the case of a woman with necrotizing fasciitis of the abdominal wall and the course and methods of treatment. Two comorbidity factors (extreme obesity, diabetes) and the late diagnosis of necrotizing fasciitis, the latter masked by celullitis and phlegmona of the abdominal wall, resulted in overdue adequate surgical treatment. The combination of these factors contributed to medical treatment failure and, consequently, a lethal outcome. PMID:17180543
Huljev, Dubravko
Mechanical response of human abdominal walls ex vivo: Effect of an incisional hernia and a mesh repair.
The design of meshes for the treatment of incisional hernias could benefit from better knowledge of the mechanical response of the abdominal wall and how this response is affected by the implant. The aim of this study was to characterise the mechanical behaviour of the human abdominal wall. Abdominal walls were tested ex vivo in three states: intact, after creation of a defect simulating an incisional hernia, and after reparation with a mesh implanted intraperitonally. For each state, the abdominal wall was subjected to air pressure loading. Local strain fields were determined using digital image correlation techniques. The strain fields on the internal and external surfaces of the abdominal wall exhibited different patterns. The strain patterns on the internal surface appeared to be related to the underlying anatomy of the abdominal wall. Higher strains were observed along the linea alba than along the perpendicular direction. Under pressure loading, the created incision increased the strain of the abdominal wall compared to the intact state in 5 cases of a total 6. In addition, the mesh repair decreased the strains of the abdominal wall compared to the incised state in 4 cases of 6. These results suggest that the intraperitoneal mesh restores at least partially the mechanical behaviour of the wall and provides quantification of the effects on the strains in various regions. PMID:25051150
Podwojewski, F; Ottķnio, M; Beillas, P; Guķrin, G; Turquier, F; Mitton, D
Thick domain walls in AdS black hole spacetimes
Equations of motion for a real self-gravitating scalar field in the background of a black hole with negative cosmological constant were solved numerically. We obtain a sequence of static axisymmetric solutions representing thick domain wall cosmological black hole systems, depending on the mass of black hole, cosmological parameter and the parameter binding black hole mass with the width of the domain wall. For the case of extremal cosmological black hole the expulsion of scalar field from the black hole strongly depends on it.
Moderski, Rafal; Rogatko, Marek [Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, 00-716 Warsaw, Bartycka 18 (Poland); Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, pl. Marii Curie-Sklodowskiej 1 (Poland)
Ultrasonic Wall Thickness Monitoring at High Temperatures (>500 ░C)
NASA Astrophysics Data System (ADS)
Corrosion and erosion shorten the life of components that are used in the petrochemical industry. In order to mitigate the safety and financial risks posed by the degradation mechanisms, plant operators monitor wall thicknesses at regular inspection intervals. In high temperature locations inspections have to be carried out at plant shut downs because conventional ultrasonic sensors cannot withstand the high operating temperatures. The authors have developed a waveguide based high temperature thickness gauge for monitoring of wall thicknesses in high temperature areas. The waveguide allows the use of conventional transduction systems (max temp. 60 ░C) at one end and guides ultrasonic waves into the high temperature region where the inspection is to be carried out. Slender stainless steel waveguides allow a temperature drop of ś500-600 ░C per 200 mm length to be sustained simply by natural convection cooling. This paper describes the technical challenges that had to be overcome (dispersion and source/receiver characteristics) in order to implement this "acoustic cable". A range of experimental results of thickness measurements on components of different thickness, and furnace tests at different temperatures are presented. An accelerated corrosion test that demonstrates the effectiveness of the monitoring for corrosion is also presented.
Cegla, F. B.; Allin, J.; Davies, J. O.; Collins, P.; Cawley, P.
Multilayer injection moulding of thick-walled optical plastics parts
NASA Astrophysics Data System (ADS)
Optical components are often thick-walled. The cycle time of precise polymer optics with a wall thickness of more than 20 mm exceeds several minutes. The multilayer injection moulding or compression moulding lowers the cycle time and increases the quality of the moulded parts. For the production of multilayer moulded lenses the mould design plays an important role. An innovative mould concept is presented with the possiblity to produce double or triple layer lenses. To ensure the quality and the endurance of multilayer moulded optical components in their applications, the cohesion in the interface is important. Tensile shear tests show the ability of multilayer moulded parts with high cohesion values for optical applications.
Hopmann, Ch.; Neuss, A.; Weber, M.; Walach, P.
Chest wall thickness measurements for enriched uranium: an alternative approach.
The Human Monitoring Laboratory has developed a technique to determine the chest wall thickness of an individual using information from the spectrum produced by internally deposited radionuclides. The technique has been investigated both theoretically and practically using phoswich detectors and the Lawrence Livermore Torso Phantom. The phantom was used with lung sets containing homogeneously distributed 93% enriched uranium, 20% enriched uranium, natural uranium, and 241Am. It was found that a 3-cm chest wall thickness can be estimated to within 9% when measuring 93% enriched uranium. The technique does not work for the latter two radionuclides because of an insufficient separation in the photon energies and poor resolution of the phoswich detectors. The technique is only of value for activity levels well above the detection limit. PMID:8175366
Kramer, G H; Puscalau, M
Evaluation of UT Wall Thickness Measurements and Measurement Methodology
CH2M HILL has requested that PNNL examine the ultrasonic methodology utilized in the inspection of the Hanford double shell waste tanks. Specifically, PNNL is to evaluate the UT process variability and capability to detect changes in wall thickness and to document the UT operator's techniques and methodology in the determination of the reported minimum and average UT data and how it compares to the raw (unanalyzed) UT data.
Weier, Dennis R.; Pardini, Allan F.
Immediate reconstruction of full-thickness chest wall defects
Twenty-one patients had full-thickness chest wall defects reconstructed at the New York University Medical Center in the last ten years. Marlex mesh provided chest wall stability in 5 patients. In 9 patients with radiation ulcers Marlex mesh was not required; a severe fibrotic reaction had obliterated the pleural space and prevented paradoxical motion. Partial sternal resections did not require Marlex stabilization, while a total sternectomy resulted in marked ventilatory insufficiency in a patient who would have benefited from the use of a stabilizing material. Random pattern flaps were used initially; more recently, axial pattern, myocutaneous, and myocutaneous free flaps were employed. Necrosis developed in 4 (36%) of the 11 patients with random pattern flaps, but was not seen with the newer flap techniques. Myocutaneous free flaps provided uncomplicated coverage of and stability to three large, potentially contaminated defects. It seems that with the currently available flap techniques and the methods of chest wall stabilization, immediate repair of all full-thickness chest wall defects is possible.
Boyd, A.D.; Shaw, W.W.; McCarthy, J.G.; Baker, D.C.; Trehan, N.K.; Acinapura, A.J.; Spencer, F.C.
Clinical significance of intraoperative cultures of aneurysm walls and contents in elective abdominal aortic aneurysmectomy
To investigate the clinical significance of intraoperative cultures in elective abdominal aortic aneurysmectomy, we cultured the aneuryrymml wall and contents in 90 patients undergoing vascular graft surgery. Prosthetic graft infection was documented in 1 out of 62 patients with negative cultures and in none of 28 patients with positive cultures (x2 = 0.4, p > 0.1). Bacterial growth was seen
C. Brandimarte; C. Santini; M. Venditti; P. Baiocchi; P. Serra; P. Gallo; G. d'Amati; L. Rizzo; F. Speziale; P. Fiorani
Biomaterials for abdominal wall hernia surgery and principles of their applications
This article focuses special attention on the porosity, cellular permeability and molecular permeability of biomaterials and their effect on infection, host tissue incorporation and seroma formation when mesh is used for the repair of abdominal wall hernias. Furthermore, the general principles of the application of biomaterials, regardless of the technique used for their employment, is discussed.
P. K. Amid; A. G. Shulman; I. L. Lichtenstein; M. Hakakha
Integration of biomaterials implanted into abdominal wall: process of scar formation and macrophage response
The behaviour of two biomaterials polytetrafluoroethylene (PTFE) and polypropylene (PL) has been studied, focussing especially on the macrophage response to the implant, as well as on certain aspects of the process of scar formation. A total of 24 animals (white New Zealand rabbits) received prostheses implanted into the anterior abdominal wall in such a way as to involve every layer
J. M. Bell¾n; J. Bujßn; L. Contreras; A. Hernando
Long-term results following repair of neonatal abdominal wall defects with Gore-Tex
Animal studies and clinical experience in adults suggest that the Gore-Tex patch, because of its strength and lack of reactivity, is superior to other synthetic materials as a fascial replacement. We report our experience with Gore-Tex for the repair of neonatal abdominal wall defects when direct fascial closure was not possible. Between January 1985 and July 1992, 84 patients underwent
Paul M. Willis; Craig T. Albanese; Marc I. Rowe; Eugene S. Wiener
Abdominal wall reconstruction with Two-step Technique (TST): a prospective study in 20 patients.
Abdominal wall defects continue to be a challenging problem for reconstructive surgeons. The aim of our study was to report a 3-year experience using a simple Two-step Technique (TST) to treat abdominal wall defects. Between January 2008 and December 2010, 20 patients with abdominal wall defects were treated by TST. Patients had a mean age of 37Ę5?▒?14Ę9?years (range: 22-85?years); 5 were women and 15 were men. The size of the defects was prospectively analysed. Early and late complications were recorded. Hospital stay, post-procedure downtime and patient overall satisfaction were systematically assessed. A secondary defect resulting from self-manipulation and an infection were responsible for a complication rate of 10%. Both underwent successful surgical revision which led to full resolution. The average hospital stay was 11Ę2?▒?4Ę9?weeks for the series. Long-term complications were scar hyperpigmentation in 11 cases, scar hypertrophy in 5 cases and scar widening in 3 cases. Mean patient satisfaction was 8Ę3?▒?0Ę5 [visual analogue scale (VAS) 0-10]. Average downtime post surgery was 4Ę1?▒?1Ę2?weeks. The mean follow-up was 24Ę6?▒?6Ę7?months. Reconstruction of abdominal wall defect with the TST is a reliable and reproducible technique. This technique provides excellent outcomes, and we anticipate that it will become widespread in the near future. PMID:23786231
Al Zarouni, Marwan; Trelles, Mario A; LeclĶre, Franck M
Reduced pulsatile wall motion of abdominal aortic aneurysms after endovascular repair
Purpose: The reduced size of abdominal aortic aneurysms (AAAs) after endovascular repair suggests lowered intraaneurysmal pressure. In the presence of endoleaks, the size is not decreased. Although postoperative intraaneurysmal pressure is difficult to record, the pulsatile wall motion (PWM) of aneurysms can be measured noninvasively. The aim of this study was to assess the PWM of AAAs before and after
Martin Malina; Toste Lõnne; Krasnodar Ivancev; Bengt Lindblad; Jan Brunkwall
Prediction of rupture risk in abdominal aortic aneurysm during observation: Wall stress versus diameter
Objectives: We previously showed that peak abdominal aortic aneurysm (AAA) wall stress calculated for aneurysms in vivo is higher at rupture than at elective repair. The purpose of this study was to analyze rupture risk over time in patients under observation. Methods: Computed tomography (CT) scans were analyzed for patients with AAA when observation was planned for at least 6
Mark F. Fillinger; Steven P. Marra; M. L. Raghavan; Francis E. Kennedy
Necrotizing Fasciitis of the Abdominal Wall as a Post-Surgical Complication: A Case Report
Necrotizing fasciitis is an acute surgical condition that demands a prompt and combined treatment. Early recognition, aggressive surgical debridement, and targeted antibiotic therapy significantly affect the overall course of treatment and, ultimately, survival. The authors present a case of a woman with necrotizing fasciitis of the abdominal wall and the course and methods of treatment with particular attention to the
Dubravko Huljev; Nastja Kucisec-Tepes
Effects of bridge exercises with a sling and vibrations on abdominal muscle thickness in healthy adults.
In the present study, we aimed to examine the changes in the thickness of the transversus abdominis (TrA) and internal oblique (Io) muscles using ultrasonography in adults who performed bridge exercises with the abdominal drawing-in maneuver and a sling and received micro vibrations. In total, 32 subjects were divided into a therapy (n=16) and control (n=16) groups. The therapy group completed nine sets, with four repetitions, of bridge exercises with the sling and received vibrations. The control group completed nine sets, with four repetitions, of bridge exercises with the sling and did not receive vibrations. The thicknesses of the TrA and Io muscles were measured in both groups using ultrasonography before and after therapy. According to the pressure applied to the biofeedback unit, both groups showed significant changes in the thicknesses of the TrA and Io muscles after therapy (P< 0.05). The change in the thickness of the TrA muscle after therapy was significantly different between the 2 groups when the pressures applied at 38, 42, and 46 mmHg (P< 0.05). Moreover, the change in the thickness of the Io muscle did not significantly different between the 2 groups at any of the pressures applied (P> 0.05). These findings indicate that approximately 15 minutes of vibrations during bridge exercises on unstable surfaces with a sling facilitates the activation of the deep trunk muscles and further enhances the activation of the TrA. PMID:25391324
Gong, Won-Tae
The effects of abdominal draw-in maneuver and core exercise on abdominal muscle thickness and Oswestry disability index in subjects with chronic low back pain
The purpose of this study was to effects of abdominal draw-in maneuver and core exercise with 4 weeks using the musculoskeletal ultrasonography on muscle thickness and disability in subjects with low back pain. Twenty patients with nonspecific back pain (abdominal draw-in maneuver group: n= 10, core exercise group: n= 10) were recruited in the study. Both group received exercise intervention 3 times a week for 4weeks. The test were based on muscle thickness (transversus abdominis; Tra, internal oblique; IO and external oblique; EO), disability (Oswestry disability index; ODI) measured immediately before and after intervention. The data was measured by SPSS program 12.0 version and analyzed by Paired t-test and Independent t-test. The following results were obtained. The thickness of IO, EO for both group significantly improved except for muscle thickness of Tra. The ODI were significant difference for both groups. As the results of this study, we suggest that it may be effective method to apply to increase for the thickness of Tra, EO using abdominal draw-in maneuver and thickness of IO using core exercise. PMID:24278873
Park, Seong-Doo; Yu, Seong-Hun
Abdominal fat thickness measurement using Focused Impedance Method (FIM) - phantom study
NASA Astrophysics Data System (ADS)
Abdominal fat thickness is a risk indicator of heart diseases, diabetes, etc., and its measurement is therefore important from the point of view of preventive care. Tetrapolar electrical impedance measurements (TPIM) could offer a simple and low cost alternative for such measurement compared to conventional techniques using CT scan and MRI, and has been tried by different groups. Focused Impedance Method (FIM) appears attractive as it can give localised information. An intuitive physical model was developed and experimental work was performed on a phantom designed to simulate abdominal subcutaneous fat layer in a body. TPIM measurements were performed with varying electrode separations. For small separations of current and potential electrodes, the measured impedance changed little, but started to decrease sharply beyond a certain separation, eventually diminishing gradually to negligible values. The finding could be explained using the intuitive physical model and gives an important practical information. TPIM and FIM may be useful for measurement of SFL thickness only if the electrode separations are within a certain specific range, and will fail to give reliable results if beyond this range. Further work, both analytical and experimental, are needed to establish this technique on a sound footing.
Haowlader, Salahuddin; Baig, Tanveer Noor; Siddique-e Rabbani, K.
What's new in medical management strategies for raised intra-abdominal pressure: evacuating intra-abdominal contents, improving abdominal wall compliance, pharmacotherapy, and continuous negative extra-abdominal pressure.
In the future, medical management may play an increasingly important role in the prevention and management of intra-abdominal hypertension (IAH). A review of different databases was used (PubMed, MEDLINE and EMBASE) with the search terms 'Intra-abdominal Pressure' (IAP), 'IAH', ' Abdominal Compartment Syndrome' (ACS), 'medical management' and 'non-surgical management'. We also reviewed all papers with the search terms 'IAH', 'IAP' and 'ACS' over the last three years, only extracting those papers which showed a novel approach in the non-surgical management of IAH and ACS.IAH and ACS are associated with increased morbidity and mortality. Non-surgical management is an important treatment option in critically ill patients with raised IAP. There are five medical treatment options to be considered to reduce IAP: 1) improvement of abdominal wall compliance; 2) evacuation of intra-luminal contents; 3) evacuation of abdominal fluid collections; 4) optimisation of fluid administration; and 5) optimisation of systemic and regional perfusion. This paper will review the first three treatment arms of the WSACS algorithm: abdominal wall compliance; evacuation of intra-luminal contents and evacuation of abdominal fluid collections. Emerging medical treatments will be analysed and finally some alternative specific treatments will be assessed. Other treatment options with regard to optimising fluid administration and systemic and regional perfusion will be described elsewhere, and are beyond the scope of this review. Medical management of critically ill patients with raised IAP should be instigated early to prevent further organ dysfunction and to avoid progression to ACS. Many treatment options are available and are often part of routine daily management in the ICU (nasogastric, rectal tube, prokinetics, enema, sedation, body position). Some of the newer treatments are very promising options in specific patient populations with raised IAP. Future studies are warranted to confirm some of these findings. PMID:25421926
De Keulenaer, Bart; Regli, Adrian; De Laet, Inneke; Roberts, Derek; Malbrain, Manu L N G
Impact of plasma tube wall thickness on power coupling in ICP sources
The inductively heated plasma source at the Institute of Space Systems was investigated with respect to the wall thickness of the plasma tube using an air plasma. For this, the wall thickness of the quartz tube was reduced in steps from 2.5 to 1.25 mm. The significance of reducing the wall thickness was analyzed with respect to both the maximum
Anuscheh Nawaz; Georg Herdrich
49 CFR 192.109 - Nominal wall thickness (t) for steel pipe.
Code of Federal Regulations, 2010 CFR
...Nominal wall thickness (t) for steel pipe. 192.109 Section...wall thickness (t ) for steel pipe. (a) If the nominal wall thickness for steel pipe is not known, it is...if the pipe is of uniform grade, size, and...
Optical resonances in tubular microcavities with subwavelength wall thicknesses
NASA Astrophysics Data System (ADS)
Based on the Mie scattering theory, we study optical resonances with whispering gallery modes (WGMs) in tubular microcavities. Rigorous formulas are present to obtain resonant wavelengths and Q factors for the WGM resonances. It is found that the Q factors of microtubes can be dramatically increased by increasing the dielectric constants in tube walls. For common SiO/SiO2 based microtubes, Q factors can be improved by one order when the microtubes are coated with thin high-index HfO2 layers (n = 1.95, thickness = 10 nm). The results could be useful for designing better optical devices based on tubular microcavities.
Zhan, Tianrong; Xu, Chun; Zhao, Fangyuan; Xiong, Zhiqiang; Hu, Xinhua; Huang, Gaoshan; Mei, Yongfeng; Zi, Jian
Terahertz inline wall thickness monitoring system for plastic pipe extrusion
Conventional and commercially available inline wall thickness monitoring systems for pipe extrusion are usually based on ultrasonic or x-ray technology. Disadvantages of ultrasonic systems are the usual need of water as a coupling media and the high damping in thick walled or foamed pipes. For x-ray systems special safety requirements have to be taken into account because of the ionizing radiation. The terahertz (THz) technology offers a novel approach to solve these problems. THz waves have many properties which are suitable for the non-destructive testing of plastics. The absorption of electrical isolators is typically very low and the radiation is non-ionizing in comparison to x-rays. Through the electromagnetic origin of the THz waves they can be used for contact free measurements. Foams show a much lower absorption in contrast to acoustic waves. The developed system uses THz pulses which are generated by stimulating photoconductive switches with femtosecond laser pulses. The time of flight of THz pulses can be determined with a resolution in the magnitude of several ten femtoseconds. Hence the thickness of an object like plastic pipes can be determined with a high accuracy by measuring the time delay between two reflections on materials interfaces e.g. at the pipe's inner and outer surface, similar to the ultrasonic technique. Knowing the refractive index of the sample the absolute layer thickness from the transit time difference can be calculated easily. This method in principle also allows the measurement of multilayer systems and the characterization of foamed pipes.
Hauck, J., E-mail: email@example.com, E-mail: email@example.com, E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: firstname.lastname@example.com; Stich, D., E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com; Heidemeyer, P., E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com; Bastian, M., E-mail: email@example.com, E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com; Hochrein, T., E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: firstname.lastname@example.com, E-mail: email@example.com [SKZ - German Plastics Center, Wuerzburg (Germany)
Thick-wall Kevlar 49/Epoxy pressure vessels
The feasibility of thick-wall composite vessels for very high pressure applications is demonstrated. Prototype vessels, in both spherical and cylindrical geometries, were designed, fabricated and burst tested. It is shown that experimental burst pressures are in excellent agreement with predicted values for burst pressures up to 60 ksi. Each unit consisted of a thin, seamless, copper liner with stainless steel fill stems and a filament-wound Kevlar 49/epoxy outer shell. Analysis of vessel performance accounted for liner thickness and yield strengths, composite thickness, mechanical properties and fiber volume fraction, and stress concentrations caused by the fill stem. Spherical vessels of three different sizes (inside diameters of 2.15 inches, 4.0 inches and 5.3 inches) with either 30 ksi or 60 ksi design burst pressure are discussed. Also, cylindrical vessels with identical liners but of two different composite thicknesses are described. These vessels achieved 50 ksi and 57 ksi burst pressures, respectively. In addition to the design considerations alluded to throughout the paper, the stress state in a thin metal liner during cyclic loading and the life prediction of composite vessels under sustained loading are discussed.
Guess, T.R.
Biological and biomechanical assessment of a long-term bioresorbable silk-derived surgical mesh in an abdominal body wall defect model
BackgroundĀĀThe patientÆs own repair of a body wall defect would be enhanced by a mechanically robust, physically tailorable, bioresorbable\\u000a mesh scaffold that: (1) supports rapid host tissue ingrowth and development, while (2) reducing the complications associated\\u000a with permanent synthetic and allogenic and xenogenic biological implants.\\u000a \\u000a \\u000a \\u000a MethodsĀĀA full-thickness 1-cm-diameter abdominal wall defect was made in 36 Sprague¢Dawley rats, which were divided
R. L. Horan; D. S. Bramono; J. R. L. Stanley; Q. Simmons; J. Chen; H. E. Boepple; G. H. Altman
A case report of ultrasound-guided interstitial brachytherapy for abdominal wall metastases of ovarian cancer
Purpose To report the treatment effect of interstitial brachytherapy for abdominal wall metastases of ovarian cancer. Material and methods The patient is a 44-year-old female with a diagnosis of stage IA ovarian cancer. After surgery and two cycles of chemotherapy with paclitaxel and carboplatin, the patient noticed dull pain in the lower abdomen and found a mass located in the subcutaneous tissue, below the operative incision. A diagnostic biopsy showed abdominal wall metastases. After external radiotherapy with a dose of 39.6 Gy in 22 fractions, the residual tumor was treated with interstitial brachytherapy under ultrasound guidance. The brachytherapy dose was 18 Gy in 6 fractions of 3 Gy each. Results After 3 weeks of brachytherapy, the tumor had disappeared completely. Interstitial brachytherapy was feasible. Conclusions Interstitial brachytherapy may be a proposed treatment strategy for inoperable superficial metastases, especially for low radiosensitivity cancer.
Shi, Dan; Wu, Ning; Zhao, Hongfu; He, Mingyuan; Han, Dongmei
Abdominal wall endometrioma: a case report and review of the literature.
Endometriosis is the presence of ectopic endometrial tissue that can respond to ovarian hormonal stimulation. Although it is uncommon, extrapelvic endometriosis can form a discrete mass known as an abdominal wall endometrioma. Endometriomas are thought to be caused by transfer of endometrial cells into a surgical wound, most often after a cesarean delivery. Endometriomas are diagnosed via ultrasound, computed tomography, magnetic resonance imaging, and ultrasound-guided fine needle aspiration. Treatment options can be medical, but surgical excision is the treatment of choice. Perioperative nursing care includes patient teaching, taking steps to prevent surgical site infection and inadvertent hypothermia, ensuring availability of supplies (eg, the graft for abdominal wall repair if needed), and postoperative pain management. PMID:20510946
Nissotakis, Christos; Zouros, Efstratios; Revelos, Kyriakos; Sakorafas, George H
Desmoid Tumor of the Anterior Abdominal Wall in Female Patients: Comparison with Endometriosis
In female patients presenting a tumor of the lower abdominal wall especially after cesarian section, an endometriotic tumor as well as an aggressive desmoid tumor should be considered. Symptoms in correlation with the monthly period can facilitate the presurgical differentiation between endometriosis and fibromatosis. Ultrasound reveals the typical location of both tumors and its remarkable sonographic appearance. In the clinical practice, the desmoid fibromatosis of the lower abdominal wall is a very rare disease. We present a case of a 25-year-old pregnant and discuss diagnostic and therapeutic options by a PubMed literature review. With the knowledge of the prognosis of the desmoid fibromatosis and the respective treatment options including wait and see, complete surgical resection with macroscopically free margins and adjuvant approaches is essential to avoid further interventions and progression of the locally destructive tumor. PMID:22778752
Krentel, H.; Tchartchian, G.; De Wilde, R. L.
Use of bovine pericardium graft for abdominal wall reconstruction in contaminated fields
AIM: To employ, in such conditions, a biological graft such as bovine pericardium that offers resistance to infection. METHODS: In our surgical department, from January 2006 to June 2010, 48 patients underwent abdominal wall reconstruction using acellular bovine pericardium; of these 34 patients had a contaminated wound due to diffuse peritonitis (complicated diverticulitis, bowel perforation, intestinal infarction, strangled hernia, etc.) and 14 patients had hernia relapse on infected synthetic mesh. RESULTS: In our series, one patient died of multi-organ failure 3 d after surgery. After placement of the pericardium mesh four cases of hernia relapse occurred. CONCLUSION: Recurrence rate is similar to that of prosthetic mesh repair and the application of acellular bovine pericardium (Tutomesh«, Tutogen Medical Gmbh Germany) is moreover a safe and feasible option that can be employed to manage complicated abdominal wall defects where prosthetic mesh is unsuitable. PMID:22905285
DÆAmbra, Luigi; Berti, Stefano; Feleppa, Cosimo; Magistrelli, Prospero; Bonfante, Pierfrancesco; Falco, Emilio
Cardiopulmonary perfomances in young children and adolescents born with large abdominal wall defects
Background\\/Purpose: As long as the survival rate of patients with abdominal wall defects (AWD) increases, information about long-term follow-up is becoming necessary. Even though quality of life in these patients, in absence of associated anomalies, appears to be unaffected, respiratory impairment soon after birth has been documented; therefore, participation in sports rarely is addressed. Methods: Eighteen patients, ranging in age
A. Zaccara; B. D. Iacobelli; A. Calzolari; A. Turchetta; C. Orazi; P. Schingo; P. Bagolan
Extragastrointestinal Stromal Tumor (EGIST) in the abdominal wall: Case report and literature review
INTRODUCTION Gastro Intestinal Stromal Tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract (GI). GIST that arises primarily outside the GI tract is termed Extragastrointestinal Stromal Tumor (EGIST). To the best of our knowledge, few cases of EGIST in the abdominal wall were reported. PRESENTATION OF CASE We present a rare case of EGIST in the abdominal wall of a 57 year-old female patient. The asymptomatic tumor was located in the superior aspect of the left rectus abdominis muscle, measured 5.4ĀūĀcmĀ5.3ĀūĀcmĀ6.9Ācm and was well circumscribed. Histological examination showed an epithelioid cell morphology. The mitotic count was 7/50 HPFs. Immunohistochemistry showed diffuse strong CD117 positivity, focal positivity for S100. The tumor was excised and the margins were free of malignancy. The patient was doing well postoperatively and was discharged on STI-571 regimen. DISCUSSION Although GIST is the most common mesenchymal tumor of the gastrointestinal tract, a case with EGIST in the abdominal wall is rare. Positive immunohistochemical staining for CD117 is a defining feature of GISTs. A great percentage of EGISTs represent a metastasis from a primary GIST. In our case, the clinical and diagnostic work-up have been proved it to be an EGIST. CONCLUSION The existing data on EGIST is insufficient to make a final conclusion regarding the malignant potential and clinicopathological factors of EGISTs that determine patient prognosis. Thus a follow-up for a long period is required. EGISTs should be kept in mind in the differential diagnosis for patients presenting with solid mass of the abdominal wall. PMID:22096744
Alkhatib, Loiy; Albtoush, Omar; Bataineh, Nesreen; Gharaibeh, Kamal; Matalka, Ismail; Tokuda, Yasuharu
Classification of biomaterials and their related complications in abdominal wall hernia surgery
SummaryĀĀThe value of the use of biomaterials for the repair of abdominal wall hernias is gaining increasing recognition. The use of\\u000a synthetic mesh to achieve a tension-free repair has resulted in a significant reduction in postoperative pain, in length of\\u000a the recovery period, and in the number of recurrences. However, certain physical properties of biomaterials can lead to undesirable\\u000a consequences.
P. K. Amid
Necrotizing fasciitis of the abdominal wall with lethal outcome: a case report
Necrotizing fasciitis is an acute surgical condition that demands prompt and multi-faceted treatment. Early recognition, aggressive\\u000a surgical debridement, and targeted antibiotic therapy significantly affect the overall course of treatment and survival. The\\u000a author reports here the case of a woman with necrotizing fasciitis of the abdominal wall and the course and methods of treatment.\\u000a Two comorbidity factors (extreme obesity, diabetes)
Dubravko Huljev
Correlations of coronary plaque wall thickness with wall pressure and wall pressure gradient: a representative case study
Background There are two major hemodynamic stresses imposed at the blood arterial wall interface by flowing blood: the wall shear stress (WSS) acting tangentially to the wall, and the wall pressure (WP) acting normally to the wall. The role of flow wall shear stress in atherosclerosis progression has been under intensive investigation, while the impact of blood pressure on plaque progression has been under-studied. Method The correlations of wall thickness (WT) with wall pressure (WP, blood pressure on the lumen wall) and spatial wall pressure gradient (WPG) in a human atherosclerotic right coronary artery were studied. The pulsatile blood flow was simulated using a three dimensional mathematical model. The blood was treated as an incompressible viscous non-Newtonian fluid. The geometry of the artery was re-constructed using an in vivo intravascular ultrasound (IVUS) 44-slice dataset obtained from a patient with consent obtained. The WT, the WP and the WPG were averaged on each slice, respectively, and Pearson correlation analysis was performed on slice averaged base. Each slice was then divided into 8 segments and averaged vessel WT, WP and WPG were collected from all 352 segments for correlation analysis. Each slice was also divided into 2 segments (inner semi-wall of bend and outer semi-wall of bend) and the correlation analysis was performed on the 88 segments. Results Under mean pressure, the Pearson coefficient for correlation between WT and WP was r?=?? 0.52 (p?0.0001) by 2-segment analysis and r?=?? 0.81 (p?0.0001) by slice averaged analysis, respectively. The Pearson coefficient for correlation between WT and WPG was r?=?0.30 (p?=?0.004) by 2-segment analysis and r?=?0.45 (p?=?0.002) by slice averaged analysis, respectively. The r-values corresponding to systole and diastole pressure conditions were similar. Conclusions Results from this representative case report indicated that plaque wall thickness correlated negatively with wall pressure (r?=??0.81 by slice) and positively with wall pressure gradient (r?=?0.45). The slice averaged WT has a strong linear relationship with the slice averaged WP. Large-scale patient studies are needed to further confirm our findings. PMID:22839647
Evolution of the wall shear stresses during the progressive enlargement of symmetric abdominal aortic aneurysms
NASA Astrophysics Data System (ADS)
The changes in the evolution of the spatial and temporal distribution of the wall shear stresses (WSS) and gradients of wall shear stresses (GWSS) at different stages of the enlargement of an abdominal aortic aneurysm (AAA) are important in understanding the aetiology and progression of this vascular disease since they affect the wall structural integrity, primarily via the changes induced on the shape, functions and metabolism of the endothelial cells. Particle image velocimetry (PIV) measurements were performed in in vitro aneurysm models, while changing their geometric parameters systematically. It has been shown that, even at the very early stages of the disease, i.e. increase in the diameter ? 50%, the flow separates from the wall and a large vortex ring, usually followed by internal shear layers, is created. These lead to the generation of WSS that drastically differ in mean and fluctuating components from the healthy vessel. Inside the AAA, the mean WSS becomes negative along most of the aneurysmal wall and the magnitude of the WSS can be as low as 26% of the value in a healthy abdominal aorta.
Salsac, A.-V.; Sparks, S. R.; Chomaz, J.-M.; Lasheras, J. C.
Impairment of Lung and Chest Wall Mechanics in Patients with Acute Respiratory Distress Syndrome Role of Abdominal Distension
Recent data have suggested that the elastic properties of the chest wall (CW) may be compromised in patients with ARDS because of abdominal distension (4). We partitioned CW and lung (L) mechan- ics, assessed the role of abdominal distension, and verified whether the underlying disease responsi- ble for ARDS affects the impairment of respiratory mechanics. Volume-pressure (V-P) curves (inter- rupter
Stress intensity factors in a reinforced thick-walled cylinder
NASA Technical Reports Server (NTRS)
An elastic thick-walled cylinder containing a radial crack is considered. It is assumed that the cylinder is reinforced by an elastic membrane on its inner surface. The model is intended to simulate pressure vessels with cladding. The formulation of the problem is reduced to a singular integral equation. Various special cases including that of a crack terminating at the cylinder-reinforcement interface are investigated and numerical examples are given. Results indicate that in the case of the crack touching the interface the crack surface displacement derivative is finite and consequently the stress state around the corresponding crack tip is bounded; and generally, for realistic values of the stiffness parameter, the effect of the reinforcement is not very significant.
Tang, R.; Erdogan, F.
The logic behind thick, liquid-walled, fusion concepts
NASA Astrophysics Data System (ADS)
It may be possible to surround the region where fusion reactions are taking place with a neutronically thick liquid blanket which has penetrations that allow only a few tenths of a percent of the neutrons to leak out. Even these neutrons can be attenuated by adding an accurately placed liquid or solid near the target to shadow-shield the beam ports from line-of-sight neutrons. The logic of such designs are discussed and their evolution is described with examples applied to both magnetic and inertial fusion (HYLIFE-II). These designs with liquid protection are self healing when exposed to pulsed loading and have a number of advantages-over the usual designs with solid first walls. For example, the liquid-protected solid components will last the life of the plant, and therefore the capacity factor is estimated to be approximately 10% higher than for the non-liquid-walled blankets, because no blanket replacement shutdowns are required. The component replacement, operations, and maintenance costs might be half the usual value because no blanket change-out costs or accompanying facilities are required. These combined savings might lower the cost of electricity by 20%. Nuclear-grade construction should not be needed, largely because the liquid attenuates neutrons and results in less activation of materials. Upon decommissioning, the reactor materials should qualify for disposal by shallow burial even when constructed of ordinary 304 stainless steel. The need for a high-intensity 14-MeV neutron test facility to develop first-wall materials is avoided or greatly reduced, saving billions of development dollars. Flowing molten Li, the molten salt Flibe (Li2BeF4), and molten Lil7Pb83 have been considered. An advantage of molten salt is that it will not burn and has a low tritium solubility and therefore low tritium inventory.
Moir, R. W.
Local influence of calcifications on the wall mechanics of abdominal aortic aneurysm
NASA Astrophysics Data System (ADS)
Finite element wall stress simulations on patient-specific models of abdominal aortic aneurysm (AAA) may provide a better rupture risk predictor than the currently used maximum transverse diameter. Calcifications in the wall of AAA lead to a higher maximum wall stress and thus may lead to an elevated rupture risk. The reported material properties for calcifications and the material properties actually used for simulations show great variation. Previous studies have focused on simplified modelling of the calcification shapes within a realistic aneurysm shape. In this study we use an accurate representation of the calcification geometry and a simplified model for the AAA. The objective of this approach is to investigate the influence of the calcification geometry, the material properties and the modelling approach for the computed peak wall stress. For four realistic calcification shapes from standard clinical CT images of AAA, we performed simulations with three distinct modelling approaches, at five distinct elasticity settings. The results show how peak wall stress is sensitive to the material properties of the calcifications. For relatively elastic calcifications, the results from the different modelling approaches agree. Also, for relatively elastic calcifications the computed wall stress in the tissue surrounding the calcifications shows to be insensitive to the exact calcification geometry. For stiffer calcifications the different modelling approaches and the different geometries lead to significantly different results. We conclude that an important challenge for future research is accurately estimating the material properties and the rupture potential of the AAA wall including calcifications.
de Putter, Sander; van de Vosse, Frans N.; Breeuwer, Marcel; Gerritsen, Frans A.
Abdominal Wall Abscess due to Acute Perforated Sigmoid Diverticulitis: A Case Report with MDCT and US Findings
Perforation of the inflamed diverticula is a common diverticulitis complication. It usually leads to the formation of a local abscess. In some rare cases, the inflammatory process may spread towards extra-abdominal sites like the anterior or posterior abdominal wall or the thigh and form an abscess in these sites. We present the case of a 73-year-old man with a history of pain at the lower left quadrant of the abdomen for 20 days and a visible mass in this site. Ultrasonography and computed tomography revealed this mass to be an abscess of the abdominal wall which had been formed by the spread of ruptured sigmoid diverticulitis by continuity of tissue through the lower left abdominal wall. Local drainage of the abscess was performed and the patient was discharged after alleviation of symptoms and an uneventful course. We also discuss causes of abdominal wall abscesses along with the possible pathways by which an intra-abdominal abscess could spread outside the abdominal cavity. PMID:24386584
Vasileios, Rafailidis; Anna, Gavriilidou; Christos, Liouliakis; Asimina, Tsimitri; Sofia, Paschaloudi; Vasiliki, Karadimou
The influence of intraluminal thrombus on noninvasive abdominal aortic aneurysm wall distensibility measurement.
Abdominal aortic aneurysm wall distensibility can be estimated by measuring pulse pressure and the corresponding sac volume change, which can be obtained by measuring wall displacement. This approach, however, may introduce error if the role of thrombus in assisting the wall in bearing the pulse pressure loading is neglected. Our aim was to introduce a methodology for evaluating and potentially correcting this error in estimating distensibility. Electrocardiogram-gated computed tomography images of eleven patients were obtained, and the volume change between diastole and systole was measured. Using finite element procedures, we determined the equivalent pulse pressure loading that should be applied to the wall of a model where thrombus was digitally removed, to yield the same sac volumetric increase caused by applying the luminal pulse pressure to the model with thrombus. The equivalent instead of the measured pulse pressure was used in the distensibility expression. For a relative volumetric thrombus deposition (V ILT) of 50Ā%, a 62Ā% distensibility underestimation resulted when thrombus role was neglected. A strong linear correlation was observed between distensibility underestimation and V ILT. To assess the potential value of noninvasive wall distensibility measurement in rupture risk stratification, the role of thrombus on wall loading should be further investigated. PMID:25548097
Metaxa, Eleni; Kontopodis, Nikolaos; Vavourakis, Vasileios; Tzirakis, Konstantinos; Ioannou, Christos V; Papaharilaou, Yannis
A simulation framework for estimating wall stress distribution of abdominal aortic aneurysm.
Abdominal aortic aneurysm (AAA) rupture is believed to occur when the mechanical stress acting on the wall exceeds the strength of the wall tissue. In endovascular aneurysm repair, a stent-graft in a catheter is released at the aneurysm site to form a new blood vessel and protect the weakened AAA wall from the pulsatile pressure and, hence, possible rupture. In this paper, we propose a framework to estimate the wall stress distribution of non-stented/stented AAA based on fluid-structure interaction, which is utilized in a surgical simulation system (IRAS). The 3D geometric model of AAA is reconstructed from computed tomography angiographic (CTA) images. Based on our experiments, a combined logarithm and polynomial strain energy equation is applied to model the elastic properties of arterial wall. The blood flow is modeled as laminar, incompressible, and non-Newtonian flow by applying Navier-Stokes equation. The obtained pressure of blood flow is applied as load on the AAA meshes with and without stent-graft and the wall stress distribution is calculated by fluid-structure interaction (FSI) solver equipped in ANSYS. Experiments demonstrate that our analytical results are consistent with clinical observations. PMID:22254456
Qin, Jing; Zhang, Jing; Chui, Chee-Kong; Huang, Wei-Min; Yang, Tao; Pang, Wai-Man; Sudhakar, Venkatesh; Chang, Stephen
Intensity modulated radiation-therapy for preoperative posterior abdominal wall irradiation of retroperitoneal liposarcomas
Purpose: Preoperative external-beam radiation therapy (preop RT) in the management of Retroperitoneal Liposarcomas (RPLS) typically involves the delivery of radiation to the entire tumor mass: yet this may not be necessary. The purpose of this study is to evaluate a new strategy of preop RT for RPLS in which the target volume is limited to the contact area between the tumoral mass and the posterior abdominal wall. Methods and Materials: Between June 2000 and Jan 2005, 18 patients with the diagnosis of RPLS have been treated following a pilot protocol of pre-op RT, 50 Gy in 25 fractions of 2 Gy/day. The Clinical Target Volume (CTV) has been limited to the posterior abdominal wall, region at higher risk for local relapse. A Three-Dimensional conformal (3D-CRT) and an Intensity Modulated (IMRT) plan were generated and compared; toxicity was reported following the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events v3.0. Results: All patients completed the planned treatment and the acute toxicity was tolerable: 2 patients experienced Grade 3 and 1 Grade 2 anorexia while 2 patients developed Grade 2 nausea. IMRT allows a better sparing of the ipsilateral and the contralateral kidney. All tumors were successfully resected without major complications. At a median follow-up of 27 months 2 patients developed a local relapse and 1 lung metastasis. Conclusions: Our strategy of preop RT is feasible and well tolerated: the rate of resectability is not compromised by limiting the preop CTV to the posterior abdominal wall and a better critical-structures sparing is obtained with IMRT.
Bossi, Alberto [Department of Radiation Oncology, University Hospitals Gasthuisberg, Leuven (Belgium)]. E-mail: firstname.lastname@example.com; De Wever, Ivo [Department of Surgical Oncology, University Hospitals Gasthuisberg, Leuven (Belgium); Van Limbergen, Erik [Department of Radiation Oncology, University Hospitals Gasthuisberg, Leuven (Belgium); Vanstraelen, Bianca [Department of Medical Physics, University Hospitals Gasthuisberg, Leuven (Belgium)
Systematic review of the use of fibrin sealant in abdominal-wall repair surgery
PurposeĀĀOur objective was to analyze the advantages and inconveniences associated with the use of fibrin sealant compared with mechanical\\u000a means for mesh fixation following abdominal-wall surgery.\\u000a \\u000a \\u000a \\u000a \\u000a MethodsĀĀLiterature search was conducted in MedLine, EMBASE, and Cochrane Library Plus databases. Articles were randomized clinical\\u000a trials, nonrandomized comparative studies, and case series containing at least ten patients.\\u000a \\u000a \\u000a \\u000a \\u000a ResultsĀĀThe fibrin sealant was shown to
S. Morales-Conde; A. Barranco; M. Socas; I. Alarc¾n; M. Grau; M. A. Casado
The muscles of the infrapubic abdominal wall of a 6-month-old Crocodylus niloticus (Reptilia: Crocodylia).
The muscles of the infrapubic abdominal wall of crocodilians play an important role in their ventilatory mechanism. Yet the anatomy and homology of these muscles is poorly understood. To gain new insights into the anatomy of the crocodilian infrapubic abdominal wall, we dissected a specimen of Crocodylus niloticus. Origin and insertion of the muscles, as well as their arrangement relative to each other was examined in great detail. The findings were compared with those of other crocodilian taxa to detect potential variability of the muscles of interest. The homology of the muscles was studied by comparing the muscles of the crocodilian infrapubic abdominal wall with those of other diapsids. In Crocodylus niloticus, the infrapubic abdominal wall consists of four muscles: Musculus truncocaudalis, M. ischiotruncus, and Mm. rectus abdominis externus and internus. The arrangement of the muscles of the infrapubic abdominal wall of Crocodylus niloticus is consistent with that found in most other crocodilian taxa. In some crocodilian taxa, an additional muscle, M. ischiopubis, is found. In the remaining diapsids, only M. rectus abdominis is present. The crocodilian M. truncocaudalis, M. ischiotruncus and, if present, M. ischiopubis appear to be derivates of M. rectus abdominis; the development of those might be related to the evolution of the unique crocodilian ventilatory mechanism. PMID:22909340
Fechner, R; Schwarz-Wings, D
The development of prosthetic biomaterials revolutionized surgery for the repair of abdominal wall hernias in humans. A tensionfree mesh technique has drastically reduced recurrence rates for all hernias compared to tissue repairs and has made it possible to reconstruct large ventral defects that were previously irreparable. Abdominal wall defects (hernias, eventrations, eviscerations) in large animals (cattles, horses) present also o
Ciprian OBER; Aurel MUSTE; Liviu OANA
Architectural Analysis of Human Abdominal Wall Muscles: Implications for Mechanical Function
Study Design Cadaveric analysis of human abdominal muscle architecture. Objective To quantify the architectural properties of rectus abdominis (RA), external oblique (EO), internal oblique (IO) and transverse abdominis (TrA), and model mechanical function in light of these new data. Summary of Background Data Knowledge of muscle architecture provides the structural basis for predicting muscle function. Abdominal muscles greatly affect spine loading, stability, injury prevention and rehabilitation; however, their architectural properties are unknown. Methods Abdominal muscles from eleven elderly human cadavers were removed intact, separated into regions and micro-dissected for quantification of physiological cross-sectional area (PCSA), fascicle length and sarcomere length. From these data, sarcomere operating length ranges were calculated. Results IO had the largest PCSA and RA the smallest, and would thus generate the largest and smallest isometric forces, respectively. RA had the longest fascicle length, followed by EO, and would thus be capable of generating force over the widest range of lengths. Measured sarcomere lengths, in the post-mortem neutral spine posture, were significantly longer in RA and EO (3.29▒0.07 and 3.18▒0.11 ?m) compared to IO and TrA (2.61▒0.06 and 2.58▒0.05 ?m) (p < 0.0001). Biomechanical modeling predicted that RA, EO and TrA act at optimal force-generating length in the mid-range of lumbar spine flexion, where IO can generate approximately 90% of its maximum force. Conclusions These data provide clinically relevant insights into the ability of the abdominal wall muscles to generate force and change length throughout the lumbar spine range of motion. This will impact the understanding of potential postures in which the force-generating and spine stabilizing ability of these muscles become compromised, which can guide exercise/rehabilitation development and prescription. Future work should explore the mechanical interactions among these muscles and their relationship to spine health and function. PMID:21325932
Brown, Stephen H. M.; Ward, Samuel R.; Cook, Mark S.; Lieber, Richard L.
Symptomatic schwannoma of the abdominal wall: A case report and review of the literature
Schwannoma is a rare, benign tumor that arises from the nerve sheath. This tumor usually involves the extremities, but can also be found in the head and neck, trunk, pelvis, retroperitoneum, mediastinum and gastrointestinal tract. In numerous cases, the tumors are asymptomatic and are identified incidentally on physical examination or imaging. Occasionally, schwannoma is symptomatic due to compression of surrounding large nerves. In the present study, a 57-year-old female presented to the surgical outpatientÆs department due to a well-localized parietal pain in the left lower quadrant. The onset of the pain occurred three years prior to presentation, without apparent cause and in the absence of other symptoms. Ultrasound and a computed tomography scan revealed a small solid tumor in the anterior abdominal wall, which was dimensionally stable over time, but was not noted in a preliminary analysis by a radiologist. The lesion was surgically removed using an anterior surgical approach. Histopathology revealed the tumor to be benign schwannoma. The painful symptoms completely disappeared. To the best of our knowledge, this is the third case of an abdominal wall benign schwannoma in the medical literature, and the first symptomatic case. PMID:25663862
Abdominal wall defect with large duodenal disruption treated by a free tissue flap with a help of temporary expandable metallic stent
Abdominal wall defect with large duodenal disruption after penetrating abdominal injury is a rare emergency situation that can result in life-threatening complications. We report on a 64-year-old man who had abdominal wall defect with large duodenal disruption after penetrating abdominal injury. The patient presented with intra-abdominal exsanguinating bleeding, duodenal disruption, and multiple small bowel perforation. The rarity of this complex injury and its initial presentation as a posttraumatic large duodenal disruption with abdominal wall defect warrant its description. The present case indicates that combining a free tissue flap with a covered expandable metallic stent can effectively and successfully repair an abdominal wall defect that is associated with a large duodenal disruption. PMID:24266016
Park, Jung-Hoon; Song, Ho-Young; Kim, Eun Key; Lee, Sung Koo; Jung, Yooun Joong
Abdominal wall competence after free transverse rectus abdominis musculocutaneous flap harvest: a prospective study.
A prospective study was designed to evaluate the possible changes in abdominal wall strength following free transverse rectus abdominis musculocutaneous (TRAM) flap surgery for breast reconstruction. Twenty-two patients were examined 1 day before surgery, and at 3, 6, and 12 months postoperatively. Trunk muscle strength was measured by the same physiotherapist using an isokinetic dynamometer (Lido Multi Joint II, Loredan Biomedical Inc., Davies, CA). The peak torque and average torque for both flexion and extension at 60 degrees per second angular velocity were recorded from the curves obtained. There was a significant reduction in trunk flexion strength at 3 months postoperatively (peak torque mean, 92% of the preoperative value; p = 0.04), but this was corrected by 6 months (mean, 96%), and improved to 98% by 12 months. The patient's ability to do curled trunk sit-ups was evaluated by the same physiotherapist and graded on a scale from 1 to 6. In 9 of 19 patients the operation had no effect on sit-up performance during follow-up. In 10 of 19 patients there was a reduction of one or two grades at 3 months that did not improve by 12 months. Magnetic resonance imaging of the abdominal wall was performed on 9 patients. The mean area of the upper third of both rectus muscles was measured on the axial images. At 3 months postoperatively the mean area of the upper third of the donor muscle was significantly larger than the contralateral (p = 0.03). There was no difference in size at 6 months, and by 12 months the donor side was smaller. This prospective study shows that harvesting of a free TRAM flap can cause a subclinical reduction in abdominal strength, although this was not noticed by the patients themselves. PMID:9326701
Suominen, S; Asko-Seljavaara, S; Kinnunen, J; Sainio, P; Alaranta, H
Pain pressure threshold algometry of the abdominal wall in healthy women
The objective of this study was to determine the inter- and intra-examiner reliability of pain pressure threshold algometry at various points of the abdominal wall of healthy women. Twenty-one healthy women in menacme with a mean age of 28 ▒ 5.4 years (range: 19-39 years) were included. All volunteers had regular menstrual cycles (27-33 days) and were right-handed and, to the best of our knowledge, none were taking medications at the time of testing. Women with a diagnosis of depression, anxiety or other mood disturbances were excluded. Women with previous abdominal surgery, any pain condition or any evidence of inflammation, hypertension, smoking, alcoholism, or inflammatory disease were also excluded. Pain perception thresholds were assessed with a pressure algometer with digital traction and compression and a measuring capacity for 5?kg. All points were localized by palpation and marked with a felt-tipped pen and each individual was evaluated over a period of 2 days in two consecutive sessions, each session consisting of a set of 14?point measurements repeated twice by two examiners in random sequence. There was no statistically significant difference in the mean pain threshold obtained by the two examiners on 2 diferent days (examiner A: P = 1.00; examiner B: P = 0.75; Wilcoxon matched pairs test). There was excellent/good agreement between examiners for all days and all points. Our results have established baseline values to which future researchers will be able to refer. They show that pressure algometry is a reliable measure for pain perception in the abdominal wall of healthy women. PMID:22527127
Montenegro, M.L.L.S.; Braz, C.A.; Mateus-Vasconcelos, E.L.; Rosa-e-Silva, J.C.; Candido-dos-Reis, F.J.; Nogueira, A.A.; Poli-Neto, O.B.
Reducing Effective Liquid Wall Thickness in a HYLIFE-II Fusion Breeder
NASA Astrophysics Data System (ADS)
One of the major inertial fusion energy reactor designs is HYLIFE-II which uses protective flowing liquid wall between fusion plasma and solid first wall. The most attractive aspect of this reactor is that protective liquid wall eliminates the frequent replacement of the first wall structure during reactor lifetime. Liquid wall thickness must be at least the thickness required for supplying sufficient tritium for the deuterium-tritium (DT) driver and satisfying radiation damage on the first wall below the limits. Reducing this thickness results less pumping power requirements and cost of electricity. In this study, investigation on potential of utilizing refractory alloys (W-5Re, TZM and Nb-1Zr) as first wall to reduce effective liquid wall thickness in HYLIFE-II reactor using liquid wall of Flibe + 10 mol % UF4 mixture. Neutron transport calculations were carried out with the help of the SCALE4.3 system by solving the Boltzmann transport equation with the XSDRNPM code in 238 neutron groups and a S8-P3 approximation. Numerical results showed that using W-5Re or TZM as first wall was effective in decreasing liquid wall thickness in contrast to Nb-1Zr.
▄beyli, Mustafa
Necrotizing cellulitis of the abdominal wall, caused by Pediococcus sp., due to rupture of a retroperitoneal stromal cell tumor
INTRODUCTION Soft tissue necrotizing infections are a significant cause of morbidity and mortality. The aim of this study is to present a patient with necrotizing infection of abdominal wall resulting from the rupture of a retroperitoneal stromal tumor. PRESENTATION OF CASE We present a 60-year-old Caucasian male patient with necrotizing infection of abdominal wall secondary to the rupture of a retroperitoneal stromal tumor. The patient was initially treated with debridement and fasciotomy of the anterior abdominal wall. Laparotomy revealed purulent peritonitis caused by infiltration and rupture of the splenic flexure by the tumor. Despite prompt intervention the patient died 19 days later. The isolated microorganism causing the infection was the rarely identified as cause of infections in humans Pediococcus sp., a gram-positive, catalase-negative coccus. DISCUSSION Necrotizing infections of abdominal wall are usually secondary either to perineal or to intra-abdominal infections. Gastrointestinal stromal cell tumors could be rarely complicated with perforation and abscess formation. In our case, the infiltrated by the extra-gastrointestinal stromal cell tumor ruptured colon was the source of the infection. The pediococci are rarely isolated as the cause of severe septicemia. CONCLUSION Ruptured retroperitoneal stromal cell tumors are extremely rare cause of necrotizing fasciitis, and before this case, Pediococcus sp. has never been isolated as the responsible agent. PMID:23357010
Michalopoulos, Nick; Arampatzi, Stergiani; Papavramidis, Theodossis S.; Kotidis, Efstathios; Laskou, Styliani; Papavramidis, Spiros T.
Effective Wall Thickness of Single-Walled Carbon Nanotubes for Multi-Scale Analysis: The Problem and a Possible Solution
Continuum mechanics models have been used to characterize the mechanical behaviour of carbon nanotubes, but their validity down to the nanometer scale has not been fully verified. A typical example is the effective wall thickness of single-walled carbon nanotubes (SWCNTs), which has not been well defined after years of effort. This paper proposes a sufficient condition for determining the effective
L. C. Zhang; C. Y. Wang
Wall "Thickness" Effects on Raman Spectrum Shift, Thermal Conductivity, and Young's Modulus of Single-Walled Nanotubes
-13 Depending on the geo- metrical structure, nanotubes can exhibit fascinating properties; for example. In addition to tube radius and length, wall thickness is another important and fundamental structure parameter on the cross section of the tubes. Therefore, any ambiguity in calculating the thickness will cause an error
Li, Baowen
A critical assessment of the elastic properties and effective wall thickness of single-walled carbon nanotubes.
This paper discusses the fundamental issues of the elastic properties and effective wall thickness of single-walled carbon nanotubes (SWCNTs). It provides an in-depth analysis based on the rationale of the nanoscale-to-macroscale deformation relationship of SWCNTs and carries out a critical assessment of the diverse theoretical predictions in the literature. It was found that the in-plane stiffness of SWCNTs is a mechanics quantity that has been consistently reflected by the majority of the existing models. However, a further systematic study is necessary to clarify the dilemma of the wall thickness of SWCNTs. PMID:21817653
Wang, C Y; Zhang, L C
Method of manufacturing hollow members having uniform wall thickness through use of ablation
A method of manufacturing a hollow structure of uniform wall thickness comprising the steps of selecting or forming a precursor having one wall surface of desired geometry, treating a portion of the precursor consisting of the one wall surface and a uniform depth of material beneath the wall surface to increase resistance to ablation, and then removing by ablation and discarding the remaining or untreated portion of the precursor.
Anderson, Paul R. (Toledo, OH); Downs, Raymond L. (Ann Arbor,, MI); Henderson, Timothy M. (Ann Arbor,, MI)
Patient-specific left atrial wall-thickness measurement and visualization for radiofrequency ablation
NASA Astrophysics Data System (ADS)
INTRODUCTION: For radiofrequency (RF) catheter ablation of the left atrium, safe and effective dosing of RF energy requires transmural left atrium ablation without injury to extra-cardiac structures. The thickness of the left atrial wall may be a key parameter in determining the appropriate amount of energy to deliver. While left atrial wall-thickness is known to exhibit inter- and intra-patient variation, this is not taken into account in the current clinical workflow. Our goal is to develop a tool for presenting patient-specific left atrial thickness information to the clinician in order to assist in the determination of the proper RF energy dose. METHODS: We use an interactive segmentation method with manual correction to segment the left atrial blood pool and heart wall from contrast-enhanced cardiac CT images. We then create a mesh from the segmented blood pool and determine the wall thickness, on a per-vertex basis, orthogonal to the mesh surface. The thickness measurement is visualized by assigning colors to the vertices of the blood pool mesh. We applied our method to 5 contrast-enhanced cardiac CT images. RESULTS: Left atrial wall-thickness measurements were generally consistent with published thickness ranges. Variations were found to exist between patients, and between regions within each patient. CONCLUSION: It is possible to visually determine areas of thick vs. thin heart wall with high resolution in a patient-specific manner.
Inoue, Jiro; Skanes, Allan C.; White, James A.; Rajchl, Martin; Drangova, Maria
The Bulging Behavior of Thick-Walled 6063 Aluminum Alloy Tubes Under Double-Sided Pressures
NASA Astrophysics Data System (ADS)
To make further exploration on the deformation behavior of tube under double-sided pressures, the thick-walled 6063 aluminum alloy tubes with an outer diameter of 65 mm and an average thickness of 7.86 mm have been used to be bulged under the combined action of internal and external pressures. In the experiment, two ends of the thick-walled tubes were fixed using the tooth and groove match. Three levels of external pressure (0 MPa, 40 MPa, and 80 MPa), in conjunction with the internal pressure, were applied on the tube outside and inside simultaneously. The effect of external pressure on the bulging behavior of the thick-walled tubes, such as the limiting expansion ratio, the bulging zone profile, and the thickness distribution, has been investigated. It is shown that the limiting expansion ratio, the bulging zone profile, and the thickness distribution in the homogeneous bulging area are all insensitive to the external pressure. However, the external pressure can make the thick-walled tube achieve a thinner wall at the fracture area. It reveals that the external pressure can only improve the fracture limit of the thick-walled 6063 tubes, but it has very little effect on their homogeneous bulging behavior. It might be because the external pressure can only increase the magnitude of the hydrostatic pressure for the tube but has no effect on the Lode parameter.
Cui, Xiao-Lei; Wang, Xiao-Song; Yuan, Shi-Jian
Impaired abdominal wall development and deficient wound healing in mice lacking aortic carboxypeptidase-like protein.
Aortic carboxypeptidase-like protein (ACLP) is a member of a diverse group of proteins that contain a domain with similarity to that of the Dictyostelium discoideum protein discoidin I. The discoidin domain has been identified in mammalian milk fat globule membrane proteins, blood coagulation factors, and receptor tyrosine kinases, where it may facilitate cell aggregation, adhesion, or cell-cell recognition. Here we show that ACLP is a secreted protein that associates with the extracellular matrix (ECM). During mouse embryogenesis, ACLP is abundantly expressed in the ECM of collagen-rich tissues, including the vasculature, dermis, and the developing skeleton. We deleted the ACLP gene in mice by homologous recombination. The majority of ACLP(-/-) mice die perinatally due to gastroschisis, a severe disruption of the anterior abdominal wall and herniation of the abdominal organs. ACLP(-/-) mice that survived to adulthood developed nonhealing skin wounds. Following injury by a dermal punch biopsy, ACLP(-/-) mice exhibited deficient wound healing compared with controls. In addition, dermal fibroblasts isolated from ACLP(-/-) 18.5-day-postconception embryos exhibited a reduced proliferative capacity compared with wild-type cells. These results indicate that ACLP is an ECM protein that is essential for embryonic development and dermal wound healing processes. PMID:11438679
Layne, M D; Yet, S F; Maemura, K; Hsieh, C M; Bernfield, M; Perrella, M A; Lee, M E
Increased Bladder Wall Thickness in Diabetic and Nondiabetic Women With Overactive Bladder
Purpose Bladder wall thickness has been reported to be associated with overactive bladder (OAB) in women. Diabetic women have an increased risk for OAB syndrome and may have an increased risk for bladder wall thickness. Methods A total of 235 female patients aged 40 to 75 years were categorized into four groups. The first group consisted of women free of urgency or urge urinary incontinence. The second group included nondiabetic women with idiopathic OAB. The third group consisted of women with diabetes and clinical OAB, and women with diabetes but without OAB constituted the fourth group. Bladder wall thickness at the anterior wall was measured by ultrasound by the suprapubic approach with bladder filling over 250 mL. Results The diabetic (third group) and nondiabetic (second group) women with OAB had significantly greater bladder wall thickness at the anterior bladder wall than did the controls. However, the difference was not significant between the diabetic (third group) and the nondiabetic (second group) women with OAB. Women with diabetes but without OAB (fourth group) had greater bladder wall thickness than did the controls but this difference was not significant. Additionally, the difference in bladder wall thickness between diabetic women with (third group) and without (fourth group) OAB was not significant. Conclusions This is the first study to show that bladder wall thickness is increased in diabetic women with and without OAB. Additionally, nondiabetic women with OAB had increased bladder wall thickness. Further studies may provide additional information for diabetic and nondiabetic women with OAB, in whom the etiopathogenesis of the disease may be similar. PMID:23869270
Ogullar, Sabri; ?ahin, Serap Baydur; Zorba, Orhan ▄nal; Akńa, G÷rkem; S³mer, Fatih; G³ney, ▄lk³ Mete; Bal?k, G³l?ah
Echinococcus multilocularis infection of the liver presenting as abdominal wall fistula.
Echinococcus multilocularis causes infection where the most commonly affected organ is the liver, followed by the lung, kidney, bone and the brain. Other sites such as the heart, spleen, pancreas and soft tissues are very rarely affected. Surgical treatment combined with chemotherapy using various technical approaches remains the main therapeutic modality for echinococcal liver disease. To the best of our knowledge there are less than five clinical cases of cutaneous presentation of liver alveolar echinococcosis described. We present a unique case of liver echinococcosis presenting as recurrent abdominal wall fistula and abscess in a 29-year-old man. Diagnosis was based on CT imaging, serological analysis and histological findings from the fistula. Medical treatment with albendazole was initiated and liver resection was performed. The patient has no symptoms and signs of recurrence 1 year after operation, while still on albendazole therapy. This case description highlights the importance of early suspicion and treatment of unusual echinococcosis clinical presentations. PMID:24810453
Juodeikis, Zygimantas; Poskus, Tomas; Seinin, Dmitrij; Strupas, Kestutis
Soft-tissue response to clinically retrieved titanium cover screws reimplanted in the rat abdominal wall.
Clinically retrieved titanium implant cover screws (BrÕnemark implant system), rinsed in saline or subjected to ultrasonic cleaning and sterilization, as well as unused sterile screws were studied by scanning electron microscopy and implanted in the rat abdominal wall for 6 weeks. Irrespective of cleaning procedure, the heads of the clinically retrieved screws were covered by numerous contaminants not present on the unused screws. The reimplanted screws elicited a different tissue response than the unused screws. The tissue response to the contaminated screws was characterized by a significantly thicker fibrous capsule and by a significantly larger number of macrophages located close to the implant. Moreover, judging from their ultrastructure, studied with transmission electron microscopy, the macrophages appeared to be in a more active state when compared to those located adjacent to unused screws. PMID:2700746
Sennerby, L; Lekholm, U; Ericson, L E
Dermatan sulfate epimerase 1 deficient mice as a model for human abdominal wall defects
Background Dermatan sulfate (DS) is a highly sulfated polysaccharide with a variety of biological functions in extracellular matrix organization and processes such as tumorigenesis and wound healing. A distinct feature of DS is the presence of iduronic acid, produced by the two enzymes, DS-epimerase 1 and 2, which are encoded by Dse and Dsel, respectively. Methods We have previously shown that Dse knockout (KO) mice in a mixed C57BL/6¢129/SvJ background have an altered collagen matrix structure in skin. In the current work we studied Dse KO mice in a pure NFR genetic background. Results Dse KO embryos and newborns had kinked tails and histological staining revealed significantly thicker epidermal layers in Dse KO mice when compared with heterozygote (Het) or wild-type (WT) littermates. Immunochemical analysis of the epidermal layers in newborn pups showed increased expression of keratin 5 in the basal layer and keratin 1 in the spinous layer. In addition, we observed an abdominal wall defect with herniated intestines in 16% of the Dse KO embryos. Other, less frequent, developmental defects were exencephaly and spina bifida. Conclusion We conclude that the combination of defective collagen structure in the dermis and imbalanced keratinocyte maturation could be responsible for the observed developmental defects in Dse KO mice. In addition, we propose that Dse KO mice could be used as a model in pathogenetic studies of human fetal abdominal wall defects. Birth Defects Research (Part A) 100:712¢720, 2014. ® 2014 Wiley Periodicals, Inc. PMID:25186462
Gustafsson, Renata; Stachtea, Xanthi; Maccarana, Marco; Grottling, Emma; Eklund, Erik; Malmstr÷m, Anders; Oldberg, ┼ke
Control of domain wall thickness by spatial modulation of uniaxial anisotropy and exchange stiffness parameters
NASA Astrophysics Data System (ADS)
The effect of spatial modulation of the uniaxial anisotropy (K) and exchange stiffness (A) parameters on the domain wall thickness was theoretically studied. We derived the Euler¢Lagrange equation and the Landau¢Lifshitz¢Gilbert equation considering the modulation of K and A, and showed that the modulation of A gives rise to an additional term consisting of the first derivatives of A and the magnetization unit vector. Owing to this term, the modulation of A is more effective to modify the domain wall thickness than K. The condition for domain wall pinning by controlling its thickness through the modulation of K and A was also obtained.
Arai, Hiroko; Imamura, Hiroshi
Method and apparatus for determining diameter and wall thickness of minute hollow spherical shells
Method and apparatus for determining diameter and wall thickness of hollow microspheres or shells wherein terminal velocities of shells traveling in fluid-filled conduits of differing diameters are measured. A wall-effect factor is determined as a ratio of the terminal velocities, and shell outside diameter may then be ascertained as a predetermined empirical function of wall-effect factor. For shells of known outside diameter, wall thickness may then be ascertained as a predetermined empirical function of terminal velocity in either conduit.
Steinman, D.A.
Method and apparatus for determining diameter and wall thickness of minute hollow spherical shells
Method and apparatus for determining diameter and wall thickness of hollow microspheres or shells wherein terminal velocities of shells traveling in fluid-filled conduits of differing diameters are measured. A wall-effect factor is determined as a ratio of the terminal velocities, and shell outside diameter may then be ascertained as a predetermined empirical function of wall-effect factor. For shells of known outside diameter, wall thickness may then be ascertained as a predetermined empirical function of terminal velocity in either conduit.
Steinman, David A. (Ann Arbor, MI)
Morphological and Mechanical Characteristics of the Reconstructed Rat Abdominal Wall Following use of a Wet Electrospun Biodegradable Polyurethane Elastomer Scaffold
Although a variety of materials are currently used for abdominal wall repair, general complications encountered include herniation, infection, and mechanical mismatch with native tissue. An approach wherein a degradable synthetic material is ultimately replaced by tissue mechanically approximating the native state could obviate these complications. We report here on the generation of biodegradable scaffolds for abdominal wall replacement using a wet electrospinning technique in which fibers of a biodegradable elastomer, poly(ester urethane)urea (PEUU), were concurrently deposited with electrosprayed serum-based culture medium. Wet electrospun PEUU (wet ePEUU) was found to exhibit markedly different mechanical behavior and to possess an altered microstructure relative to dry processed ePEUU. In a rat model for abdominal wall replacement, wet ePEUU scaffolds (1 ū 2.5 cm) provided a healing result that developed toward approximating physiologic mechanical behavior at 8 wks. An extensive cellular infiltrate possessing contractile smooth muscle markers was observed together with extensive extracellular matrix (collagens, elastin) elaboration. Control implants of dry ePEUU and expanded polytetrafluoroethylene did not experience substantial cellular infiltration and did not take on the native mechanical anisotropy of the rat abdominal wall. These results illustrate the markedly different in vivo behavior observed with this newly reported wet electrospinning process, offering a potentially useful refinement of an increasingly common biomaterial processing technique. PMID:20138661
Hashizume, Ryotaro; Fujimoto, Kazuro L.; Hong, Yi; Amoroso, Nicholas J.; Tobita, Kimimasa; Miki, Toshio; Keller, Bradley B.; Sacks, Michael S.; Wagner, William R.
Aneurysm-Express: Human Abdominal Aortic Aneurysm Wall Expression in Relation to Heterogeneity and Vascular Events ¢ Rationale and Design
Objective: Elective repair of abdominal aortic aneurysms (AAA) is associated with significant morbidity and mortality. Large amounts of AAA tissue are necessary to assess heterogeneity among AAA and to correct for potential confounders such as known risk factors. The Aneurysm-express study aims to identify different types of AAA using inflammatory markers in the aneurysm wall that predict postoperative cardiovascular adverse
R. Hurks; I. E. Hoefer; A. Vink; J.-P. P. M. de Vries; R. H. Heijmen; A. H. Schoneveld; M. Kerver; G. Pasterkamp; F. L. Moll
Comparison of polypropylene and polyethylene terephthalate (Dacron) meshes for abdominal wall hernia repair: A chemical and morphological study
For the first time, by scanning electron microscopy (SEM), polypropylene (PP) excised meshes (ethylene oxide sterilized) for abdominal wall hernia repair have been shown to be greatly damaged physically, independently of the implantation time, while the polyethylene terephthalate (PET), or Dacron, ones (gamma radiation sterilized), did not undergo alterations due to the sterilization process and were not damaged, even after
P. Bracco; V. Brunella; L. Trossarelli; A. Coda; F. Botto-Micca
Method of controlling the side wall thickness of a turbine nozzle segment for improved cooling
A gas turbine nozzle segment has outer and inner bands and a vane extending therebetween. Each band has a side wall, a cover and an impingement plate between the cover and nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through apertures of the impingement plate to cool the nozzle wall. The side wall of the band has an inturned flange defining with the nozzle wall an undercut region. The outer surface of the side wall is provided with a step prior to welding the cover to the side wall. A thermal barrier coating is applied in the step and, after the cover is welded to the side wall, the side wall is finally machined to a controlled thickness removing all, some or none of the coating.
Burdgick, Steven Sebastian (Schenectady, NY)
Optimization of Part Wall Thicknesses to Reduce Warpage of Injection-Molded Parts Based on The Modified Complex Method
The objective of this work is to minimize warpage of injection-molded parts by deliberately varying each part wall thickness within prescribed dimensional tolerance. The continuous design space of wall thicknesses is explored in search of the optimum wall thickness for given process conditions. The objective function to be minimized is the numeric warpage value, which requires extensive computational time. Once
B. H. Lee; B. H. Kim
Evaluation of discontinuity stresses in thick walled cylindrical shells by means of an embedded polariscope
EVALUATION OF DISCONTINUITY STRESSES IN THICK WALLED CYLINDRICAL SHELLS BY MEANS OF AN EMBEDDED POLARISCOPE A Thesis By NARCISO ORTIZ CANO, JR. Submitted to the Graduate College of the Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE January, 196B Major Sub)ect: Aerospace Engineering EVALUATION OF DISCONTINUITY STRESSES IN THICK WALLED CYLINDRICAL SHELLS BY MEANS OF AN EMBEDDED POLARISCOPE A Thesis By NARCISO ORTIZ CANO, JR. Approved...
Cano, Narciso Ortiz
Post-cast EDM method for reducing the thickness of a turbine nozzle wall
A post-cast EDM process is used to remove material from the interior surface of a nozzle vane cavity of a turbine. A thin electrode is passed through the cavity between opposite ends of the nozzle vane and displaced along the interior nozzle wall to remove the material along a predetermined path, thus reducing the thickness of the wall between the cavity and the external surface of the nozzle. In another form, an EDM process employing a profile as an electrode is disposed in the cavity and advanced against the wall to remove material from the wall until the final wall thickness is achieved, with the interior wall surface being complementary to the profile surface.
Jones, Raymond Joseph (Duanesburg, NY); Bojappa, Parvangada Ganapathy (Schenectady, NY); Kirkpatrick, Francis Lawrence (Galway, NY); Schotsch, Margaret Jones (Clifton Park, NY); Rajan, Rajiv (Guilderland, NY); Wei, Bin (Mechanicville, NY)
Changes in muscle strength and pain in response to surgical repair of posterior abdominal wall disruption followed by rehabilitation
Background: Posterior abdominal wall deficiency (PAWD) is a tear in the external oblique aponeurosis or the conjoint tendon causing a posterior wall defect at the medial end of the inguinal canal. It is often known as sportsman's hernia and is believed to be caused by repetitive stress. Objective: To assess lower limb and abdominal muscle strength of patients with PAWD before intervention compared with matched controls; to evaluate any changes following surgical repair and rehabilitation. Methods: Sixteen subjects were assessed using a questionnaire, isokinetic testing of the lower limb strength, and pressure biofeedback testing of the abdominals. After surgery and a six week rehabilitation programme, the subjects were re-evaluated. A control group were assessed using the same procedure. Results: Quadriceps and hamstrings strength was not affected by this condition. A deficit hip muscle strength was found on the affected limb before surgery, which was significant for the hip flexors (p = 0.05). Before surgery, 87% of the patients compared with 20% of the controls failed the abdominal obliques test. Both the injured and non-injured sides had improved significantly in strength after surgery and rehabilitation. The strength of the abdominal obliques showed the most significant improvement over the course of the rehabilitation programme. Conclusions: Lower limb muscle strength may have been reduced as the result of disuse atrophy or pain inhibition. Abdominal oblique strength was deficient in the injured patients and this compromises rotational control of the pelvis. More sensitive investigations (such as electromyography) are needed to assess the link between abdominal oblique function and groin injury. PMID:12547744
Hemingway, A; Herrington, L; Blower, A
Effective Wall Thickness of Single-Walled Carbon Nanotubes for Multi-Scale Analysis: The Problem and a Possible Solution
Continuum mechanics models have been used to characterize the mechanical behaviour of carbon nanotubes, but their validity\\u000a down to the nanometer scale has not been fully verified. A typical example is the effective wall thickness of single-walled\\u000a carbon nanotubes (SWCNTs), which has not been well defined after years of effort. This paper proposes a sufficient condition for determining the effective
L. C. Zhang; C. Y. Wang
Clear cell carcinoma arising from abdominal wall endometriosis: a unique case with bladder and lymph node metastasis.
The malignant transformation of abdominal wall endometriosis is a rare event and poorly understood. Less than 30 cases have been reported in the literature. Most of the reported cases have a solitary tumor in the abdominal scar. A few cases have metastasis. Here we report a case of clear cell carcinoma in abdominal wall endometriosis with bladder and lymph system metastasis. The patient had a history of abdominal wall endometriosis and recently developed symptoms of urgent urination and inguinal mass. Physical examination and a computed tomography (CT) scan detected lymph node metastasis. CT and cystoscopy confirmed bladder involvement. The patient underwent extensive surgery and chemotherapy. Pathological analysis made a diagnosis of clear cell carcinoma with bladder and lymph node metastasis. The patient was followed up and died of the disease. Symptoms of bladder invasion and lymph node spread could be a sign of malignant transformation. Local invasion and lymph node spread are two important forms of tumor metastasis. Extensive lymph nodes metastasis might be related with poor prognosis. PMID:24597651
Liu, Haiyuan; Leng, Jinghua; Lang, Jinghe; Cui, Quancai
3-D segmentation and quantitative analysis of inner and outer walls of thrombotic abdominal aortic aneurysms
NASA Astrophysics Data System (ADS)
An abdominal aortic aneurysm (AAA) is an area of a localized widening of the abdominal aorta, with a frequent presence of thrombus. A ruptured aneurysm can cause death due to severe internal bleeding. AAA thrombus segmentation and quantitative analysis are of paramount importance for diagnosis, risk assessment, and determination of treatment options. Until now, only a small number of methods for thrombus segmentation and analysis have been presented in the literature, either requiring substantial user interaction or exhibiting insufficient performance. We report a novel method offering minimal user interaction and high accuracy. Our thrombus segmentation method is composed of an initial automated luminal surface segmentation, followed by a cost function-based optimal segmentation of the inner and outer surfaces of the aortic wall. The approach utilizes the power and flexibility of the optimal triangle mesh-based 3-D graph search method, in which cost functions for thrombus inner and outer surfaces are based on gradient magnitudes. Sometimes local failures caused by image ambiguity occur, in which case several control points are used to guide the computer segmentation without the need to trace borders manually. Our method was tested in 9 MDCT image datasets (951 image slices). With the exception of a case in which the thrombus was highly eccentric, visually acceptable aortic lumen and thrombus segmentation results were achieved. No user interaction was used in 3 out of 8 datasets, and 7.80 +/- 2.71 mouse clicks per case / 0.083 +/- 0.035 mouse clicks per image slice were required in the remaining 5 datasets.
Lee, Kyungmoo; Yin, Yin; Wahle, Andreas; Olszewski, Mark E.; Sonka, Milan
Comparison of the thicknesses of the transversus abdominis and internal abdominal obliques during plank exercises on different support surfaces
[Purpose] This study applied variable plank exercises on a stable surface consisting of a mat, on an unstable surface consisting of a dynamic cushion placed under the upper extremities and lower extremities. [Subjects] Forty-three healthy male and female subjects in their 20s voluntarily consented to participate in this study. [Methods] The subjects performed the plank exercises on the three support surfaces. Ultrasound imaging was conducted while they carried out plank exercises. [Results] The changes in the thicknesses of both the transversus abdominis and internal abdominal obliques were statistically more significant for LEDCP than for MatP. In addition, the changes in the thickness of the transversus abdominis were statistically more significant for LEDCP than for UEDCP. [Conclusion] Therefore, applying an unstable condition to the lower limbs using a dynamic cushion is considered more effective during plank exercises. PMID:25642065
Do, Yong-chan; Yoo, Won-gyu
Early escharotomy as a measure to reduce intraabdominal hypertension in full-thickness burns of the thoracic and abdominal area.
Intraabdominal hypertension (IAH) can occur in critically ill patients who have undergone surgery, who have required fluid resuscitation after intraabdominal operations, or whose abdominal surgical wound closure was under tension. If IAH remains unrelieved, it can lead to development of the abdominal compartment syndrome (ACS). The latter presents with severe cardiorespiratory and urinary symptoms such as hypotension, hypoventilation, and oliguria, and it can become fatal if it is not diagnosed early and treated properly. Moreover, IAH has been documented in the context of major burns, complicating the initial resuscitation of these patients. This study was set up to investigate the role of full-thickness burns of the thoracic and abdominal areas in IAH during the early resuscitation period, to determine whether escharotomy could influence its levels. During the past 2 years 10 burn patients were enrolled in this study, as they fulfilled the necessary criteria: >35% total body surface area (TBSA) full-thickness burn affecting the anterior, lateral, and most of the posterior surface of the thorax and abdomen (torso), no respiratory mechanical support at admission, and initial evaluation at another facility and transfer to our burn center 2-6 h postburn. Upon admission, the following parameters (indicative of intraabdominal hypertension, IAH) were measured: bladder pressure and gastric pressure. Also, we monitored inferior vena cava pressure, and as a routine, central venous pressure, systolic blood pressure, and arterial blood gases. Elevated intraabdominal pressure to hazardous levels was documented in all patients included in our study. The same escharotomy pattern was performed in every case, and 5-10 min after the procedure all measurements were repeated. Immediate improvement of all the parameters measured was recorded, and the alterations were found statistically significant. These results were indicative of significant relief of the elevated intraabdominal pressure in all patients after escharotomy, as well as the efficacy of the procedure. It is thus demonstrated that full-thickness burns of the thoracic and abdominal areas can cause a significant early increase in intraabdominal pressure that, if left untreated, can lead to the development of ACS. However, the application of simple decompression techniques can offer remarkable, immediate, and often lifesaving results and is absolutely indicated for this reason, as well as for its well-known beneficial effects on respiratory function. PMID:14595519
Tsoutsos, Demosthenis; Rodopoulou, Stavroula; Keramidas, Evangelos; Lagios, Miltiadis; Stamatopoulos, Konstantinos; Ioannovich, John
A Comparison of Vaginal Pressures and Abdominal Muscle Thickness According to Childbirth Delivery Method during the Valsalva Maneuver.
[Purpose] The purpose of this study was to compare the effect of childbirth delivery method on vaginal pressure and abdominal thickness during the Valsalva maneuver (VAL). [Subjects] Thirty healthy female volunteers (26-39?years of age) were selected for this research. Their delivery histories were: nulliparous 10, vaginal delivery 10, and Cesarean delivery 10. None of the participants had a history of incontinence. [Methods] In the crook-lying position, a perineometer probe was inserted into the vagina and the transducer was placed transversely on the right side of the body during the Valsalva maneuver. [Results] There were significant differences in the thickness of the transverses abdominis (TrA) between in all the groups rest and the Valsalva maneuver, and there were significant differences in the internus oblique (IO) in the nulliparous group. During the Valsalva maneuver, there were significant differences in the TrA between the nulliparous group and the vaginal delivery group, and there were significant differences in the IO between the nulliparous delivery group and the vaginal delivery group, and between the nulliparous group and the Cesarean section group. Delivery history changed vaginal pressure, and there were significant differences between the nulliparous group and the vaginal delivery group, and between the nulliparous group and the Cesarean delivery group. [Conclusion] Pregnancy and delivery method may affect pelvic floor and abdominal muscles during the Valsalva maneuver. PMID:24707104
Kim, Haroo; Kak, Hwang-Bo; Kim, Boin
A Comparison of Vaginal Pressures and Abdominal Muscle Thickness According to Childbirth Delivery Method during the Valsalva Maneuver
[Purpose] The purpose of this study was to compare the effect of childbirth delivery method on vaginal pressure and abdominal thickness during the Valsalva maneuver (VAL). [Subjects] Thirty healthy female volunteers (26¢39?years of age) were selected for this research. Their delivery histories were: nulliparous 10, vaginal delivery 10, and Cesarean delivery 10. None of the participants had a history of incontinence. [Methods] In the crook-lying position, a perineometer probe was inserted into the vagina and the transducer was placed transversely on the right side of the body during the Valsalva maneuver. [Results] There were significant differences in the thickness of the transverses abdominis (TrA) between in all the groups rest and the Valsalva maneuver, and there were significant differences in the internus oblique (IO) in the nulliparous group. During the Valsalva maneuver, there were significant differences in the TrA between the nulliparous group and the vaginal delivery group, and there were significant differences in the IO between the nulliparous delivery group and the vaginal delivery group, and between the nulliparous group and the Cesarean section group. Delivery history changed vaginal pressure, and there were significant differences between the nulliparous group and the vaginal delivery group, and between the nulliparous group and the Cesarean delivery group. [Conclusion] Pregnancy and delivery method may affect pelvic floor and abdominal muscles during the Valsalva maneuver. PMID:24707104
Kim, Haroo; Kak, Hwang-Bo; Kim, Boin
Metastatic breast carcinoma of the abdominal wall muscle: a case report.
Metastasis from breast carcinoma is an uncommon occurrence in skeletal muscle, compared to local invasion into muscle from direct tumor spread. A 49-year-old woman was referred to our hospital with an 8.5-cm mass in the right breast. Core needle biopsy revealed metaplastic carcinoma with squamous metaplasia. The mass was rapidly growing and metaplastic, so mastectomy with dissection of axillary lymph nodes was performed. Pathological examination showed metaplastic carcinoma, histological grade 3, triple negative, and a MIB-1 labeling index of 80%. Six months postoperatively, during adjuvant chemotherapy treatment, she reported numbness and pain in the right lateral thigh and a mass in the right lower abdomen. Computed tomography revealed multiple lined masses in the abdominal wall and iliac muscle. Core needle biopsy showed metastatic breast carcinoma. Radio- and chemotherapy were administered, but the mass in the muscle became enlarged. To control her pain, a combined treatment with morphine, fentanyl, ketamine, antiepilepsy drug, and NSAIDs was administered. Liver metastasis appeared 9Āmonths (15Āmonths postoperatively) after recognition of muscle metastasis, and the patient died 16Āmonths postoperatively. Skeletal muscle metastasis is uncommon, and therapeutic intervention is mainly palliative. The most common symptom of skeletal muscle metastasis is pain; thus, pain control is a pivotal goal of treatment. PMID:22382812
Ogiya, Akiko; Takahashi, Kaoru; Sato, Mutsumi; Kubo, Yoshiko; Nishikawa, Noriko; Kikutani, Mariko; Tadokoro, Yukiko; Tanaka, Kumiko; Uematsu, Takayoshi; Watanabe, Junichiro; Kasami, Masako; Yamasaki, Seiji
Prosthetic abdominal wall hernia repair in emergency surgery: from polypropylene to biological meshes
The use of nonabsorbable prosthetic materials such as polypropylene, polyester, and ePTFE, have expanded and are now widely used in reparative surgery for abdominal wall hernias. There are still difficulties to find correct indication for prosthetic implant in emergency hernia surgery: as a matter of fact there is still a great debate if to use non-absorbable prostheses in potentially or truly infected operating fields [e.g. after intestinal resections]. All these problems can be avoided with the use of absorbable prosthetic materials such as those composed of lactic acid polymers or lactic and glycolic acid copolymers: however, the use of these absorbable prosthesis exposes the patient to a rapid and inevitable hernia recurrence. It is important to remember that prosthetic repair has been proven to have a significant less risk of recurrence than repair with direct sutures. Recently, new "biologic" prosthetic materials have been developed and proposed for the clinical use in infected fields. These materials can be called "remodeling" for the way by which they are replaced after their placement within the patient. The "remodeling" process is made possible through a process of incorporation, where a reproduction of a site-specific tissue similar to the original host tissue is created. PMID:19055805
Campanelli, G; Catena, F; Ansaloni, L
Simultaneous Prosthetic Mesh Abdominal Wall Reconstruction with Abdominoplasty for Ventral Hernia and Severe Rectus Diastasis Repairs
Background: Standard abdominoplasty rectus plication techniques may not suffice for severe cases of rectus diastasis. In the authorsÆ experience, prosthetic mesh facilitates the repair of severe rectus diastasis with or without concomitant ventral hernias. Methods: A retrospective review of all abdominal wall surgery patients treated in the past 8 years by the senior author (G.A.D.) was performed. Patients with abdominoplasty and either rectus diastasis repair with mesh or a combined ventral hernia repair were analyzed. Results: Thirty-two patients, 29 women and three men, underwent mesh-reinforced midline repair with horizontal or vertical abdominoplasty. Patient characteristics included the following: mean age, 53 years; mean body mass index, 26 kg/m2; average width of diastasis or hernia, 6.7 cm; and average surgery time, 151 minutes. There were no surgical-site infections and two surgical-site occurrencesŚtwo seromas treated with drainage in the office. After an average of 471 daysÆ follow-up, none of the patients had recurrence of a bulge or a hernia. Conclusions: For patients with significant rectus diastasis, with or without concomitant hernias, the described mesh repair is both safe and durable. Although this operation requires additional dissection and placement of prosthetic mesh in the retrorectus plane, it may be safely combined with standard horizontal or vertical abdominoplasty skin excision techniques to provide an aesthetically pleasing overall result. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV. PMID:25539311
Cheesborough, Jennifer E.
Psychosocial adjustment and physical growth in children with imperforate anus or abdominal wall defects.
Pediatric surgeons have the unique responsibility of performing surgical procedures that will enable their patients to function normally throughout a lifetime. Good anatomic results may not ensure that this goal will be achieved. Using a battery of psychological testing instruments, we evaluated the academic achievement and psychosocial status of 56 children (mean age, 10.6 years) with imperforate anus (IA) and abdominal wall defects (AWDs). Physical growth was assessed by measurement of standard anthropometric parameters, and a parent questionnaire was used to define clinical status. As a group, the children presented with average intellectual ability. Achievement in both reading and math was in the normal range. In 12.5% of the children a reading learning disability was noted and 10.7% had a disability in math. On the basis of parental assessments, 25% of the children demonstrated externalizing behavior disorders (eg, conduct problems) and 29% displayed internalizing symptomatology (eg. withdrawal, anxiety). Social competency deficits were described in 23% of the children. Data obtained from the teachers were consistent with the parental assessments. No major differences between the IA and AWD patients in academic achievement, psychosocial status, or physical growth were discovered. Routine screening of these children for learning disabilities and behavior problems is recommended. PMID:1834823
Ginn-Pease, M E; King, D R; Tarnowski, K J; Green, L; Young, G; Linscheid, T R
An Elastomeric Patch Electrospun from a Blended Solution of Dermal Extracellular Matrix and Biodegradable Polyurethane for Rat Abdominal Wall Repair
A biodegradable elastomeric scaffold was created by electrospinning a mixed solution of poly(ester urethane)urea (PEUU) and porcine dermal extracellular matrix (dECM) digest, with PEUU included to provide elasticity, flexibility, and mechanical support and dECM used to enhance bioactivity and biocompatibility. Micrographs and differential scanning calorimetry demonstrated partial miscibility between PEUU and dECM. With greater dECM content, scaffolds were found to possess lower breaking strains and suture retention strength, although initial modulus was greater with higher dECM concentrations. The hybrid scaffolds containing 0% to 50% dECM had tensile strengths of 5 to 7?MPa, breaking strains of 138% to 611%, initial moduli of 3 to 11 Mpa, and suture retention strengths of 35 to 59?MPa. When hydrated, scaffolds were found to contract markedly with 50% dECM content. When used in a rat full-thickness abdominal wall replacement model, no herniation, infection, or tissue adhesion was observed after 4 and 8 weeks with a scaffold containing 25% dECM or a control 100% PEUU scaffold. Scaffolds incorporating dECM were significantly thicker at the time of explant, with greater numbers of associated smooth muscle actin¢positive staining cells than in the control, but minimal cellular infiltration and remodeling of the scaffold were detected regardless of dECM addition. The processing of dECM and PEUU from a mixed solution thus provided a scaffold with evidence of better bioactivity and with mechanical properties not achievable with digested dECM alone. PMID:21933017
Hong, Yi; Takanari, Keisuke; Amoroso, Nicholas J.; Hashizume, Ryotaro; Brennan-Pierce, Ellen P.; Freund, John M.; Badylak, Stephen F.
Use of a pre-expanded "propeller" deep inferior epigastric perforator (DIEP) flap for a large abdominal wall defect.
Large abdominal wall soft tissue defects are traditionally reconstructed using loco-regional flaps and/or tissue expanders. Pedicled perforator flaps offer similar tissue coverage with minimal donor site morbidity and do not require microsurgical skills. The deep inferior epigastric perforator (DIEP) flap has become increasingly popular for breast reconstruction and offers abundant soft tissue while permitting primary donor site closure. To minimize operative sessions, recovery time, donor site morbidity, and avoid microsurgery, we combined tissue expansion with a "propeller" flap design and report this first case of a pre-expanded pedicled perforator flap based on the DIEP to address a large abdominal wall defect due to a burn injury. PMID:23031631
Cheng, Angela; Saint-Cyr, Michel
Patient-specific models of wall stress in abdominal aortic aneurysm: a comparison between MR and CT
NASA Astrophysics Data System (ADS)
Finite element method based patient-specific wall stress in abdominal aortic aneurysm (AAA) may provide a more accurate rupture risk predictor than the currently used maximum transverse diameter. In this study, we have investigated the sensitivity of the wall stress in AAA with respect to geometrical variations. We have acquired MR and CT images for four patients with AAA. Three individual users have delineated the AAA vessel wall contours on the image slices. These contours were used to generate synthetic feature images for a deformable model based segmentation method. We investigated the reproducibility and the influence of the user variability on the wall stress. For sufficiently smooth models of the AAA wall, the peak wall stress is reproducible for three out of the four AAA geometries. The 0.99 percentiles of the wall stress show excellent reproducibility for all four AAAs. The variations induced by user variability are larger than the errors caused by the segmentation variability. The influence of the user variability appears to be similar for MR and CT. We conclude that the peak wall stress in AAA is sensitive to small geometrical variations. To increase reproducibility it appears to be best not to allow too much geometrical detail in the simulations. This could be achieved either by using a sufficiently smooth geometry representation or by using a more robust statistical parameter derived from the wall stress distribution.
de Putter, Sander; Breeuwer, Marcel; van de Vosse, Frans N.; Kose, Ursula; Gerritsen, Frans A.
Successful Treatment of Mesenteric Varices After Living Donor Liver Transplantation with Retrograde Transvenous Obliteration Via an Abdominal Wall Vein
Balloon-occluded retrograde transvenous obliteration is an established treatment for gastric varices; it has been used more rarely to treat mesenteric varices. We report a 12-year-old girl who had received a living donor liver transplant and suffered melena due to ruptured mesenteric varices. We addressed treatment of the mesenteric varices by retrograde transvenous obliteration of an abdominal wall collateral vein detected by superior mesenteric arteriography.
Ikeda, Osamu, E-mail: firstname.lastname@example.com; Tamura, Yoshitaka; Nakasone, Yutaka; Yamashita, Yasuyuki [Kumamoto University Graduate School of Medical and Pharmaceutical Sciences, Department of Diagnostic Radiology (Japan); Okajima, Hideaki; Asonuma, Katsuhiro; Inomata, Yukihiro [Kumamoto University Graduate School of Medical and Pharmaceutical Sciences, Department of Transplantation and Pediatric Surgery (Japan)
[Preperitoneal suprainguinal access with prosthesis of the anterior abdominal wall in treatment of complex forms of incarcerated inguinal hernias].
The article describes a non-typical access to treatment of gigantic incarcerated inguinal hernias. Preperitoneal suprainguinal access allows solution of the main task of operative aid in this pathology: inspection of the strangulated organs, safe dissection of the incarcerating ring and prosthesis of the anterior abdominal wall. This method in many aspects is comparable with traditional methods of hernioplasty, but the postoperative quality of life is much better. PMID:20552796
Fedoseev, A V; Leonchenko, S V; Faber, M I; Murav'ev, S Iu
Airway wall thickness assessment: a new functionality in virtual bronchoscopy investigation
NASA Astrophysics Data System (ADS)
While classic virtual bronchoscopy offers visualization facilities for investigating the shape of the inner airway wall surface, it provides no information regarding the local thickness of the wall. Such information may be crucial for evaluating the severity of remodeling of the bronchial wall in asthma and to guide bronchial biopsies for staging of lung cancers. This paper develops a new functionality with the virtual bronchoscopy, allowing to estimate and map the information of the bronchus wall thickness on the lumen wall surface, and to display it as coded colors during endoluminal navigation. The local bronchus wall thickness estimation relies on a new automated 3D segmentation approach using strong 3D morphological filtering and model-fitting. Such an approach reconstructs the inner/outer airway wall surfaces from multi-detector CT data as follows. First, the airway lumen is segmented and its surface geometry reconstructed using either a restricted Delaunay or a Marching Cubes based triangulation approach. The lumen mesh is then locally deformed in the surface normal direction under specific force constraints which stabilize the model evolution at the level of the outer bronchus wall surface. The developed segmentation approach was validated with respect to both 3D mathematicallysimulated image phantoms of bronchus-vessel subdivisions and to state-of-the-art cross-section area estimation techniques when applied to clinical data. The investigation in virtual bronchoscopy mode is further enhanced by encoding the local wall thickness at each vertex of the lumen surface mesh and displaying it during navigation, according to a specific color map.
Saragaglia, A.; Fetita, C.; Brillet, P. Y.; PrĻteux, F.; Grenier, P. A.
The venous anatomy of the abdominal wall for Deep Inferior Epigastric Artery (DIEP) flaps in breast reconstruction
Background Despite improving outcomes, venous problems in the harvest of deep inferior epigastric artery perforator (DIEP) flaps remain the more common vascular complications. However, it is apparent that the venous anatomy of the anterior abdominal wall has not been described to the same extent as the arterial anatomy. Cadaveric dissection studies of venous anatomy frequently lack the detail of their arterial counterparts. Venous valves complicate retrograde injection, resulting in poor quality studies with limited anatomical information. Methods The current manuscript comprises a review of the literature, highlighting key features of the anatomy of the venous drainage of the abdominal wall integument, with particular pertinence to DIEP flaps. Both cadaveric and clinical studies are included in this review. Our own cadaveric and in-vivo studies were undertaken and included in detail in this manuscript, with the cadaveric component utilizing direct catheter venography and the in-vivo studies were undertaken using preoperative computed tomographic angiography (CTA), mapping in-vivo venous flow. Results Several key features of the venous anatomy of the abdominal wall render it different to other regions, and are of particular importance to DIEP flap transfer. Conclusions The cause of venous compromise is multi-factorial, with perforator diameter, midline crossover, and deep-superficial venous communications all important. Venous cadaveric studies as well as clinical CTA preoperatively can identify these anomalies. PMID:25083432
Ashton, Mark W
High Reproducibility of Adhesion Formation in Rat with Meso-Stitch Approximation of Injured Cecum and Abdominal Wall
Objective: Peritoneal adhesions following surgery are a common, serious pathology with severe complications. Appropriate animal adhesion models are essential for the assessment of adhesion preventing medical devices. This study introduces a variation of an established rat model in which highest degree adhesions are induced with excellent reproducibility (OPAM = optimized peritoneal adhesion model). Thus, this model seems to be eligible to study effects of adhesion preventing devices. Methods: 24 Lewis male rats were divided into four groups (OPAM, WSFX, sham-OPAM, sham-WSFX). The OPAM technique comprised cecal abrasion, creation of an abdominal wall defect plus approximation of injured areas by a suture, which was compared to a setting of lesions without suture fixation (WSFX). All rats were sacrificed at day 7. Macroscopic and histopathological evaluations were performed. Results were statistically analyzed using ANOVA and Dunnett's test. Results: In OPAM rats macroscopic analyses revealed a 90% incidence adhesion of cecum to the abdominal wall, all adhesions imposing as complete agglutination. In WSFX animals incidence of adhesions formation was 75%, while in both sham groups there were no adhesions at all. Histology showed the structure of adhesions with merged smooth muscle of colon and skeletal muscle of abdominal wall in all cases. Conclusion: OPAM technique provides adhesions of injured areas with a better probability than with conventional methods. All OPAM adhesions impressed as highest degree adhesions, i.e. agglutination. Due to high reproducibility in incidence and extend of adhesion formation, the OPAM is recommended for testing of adhesion prevention medical devices. PMID:25552912
Poehnert, Daniel; Abbas, Mahmoud; Kreipe, Hans-Heinrich; Klempnauer, Juergen; Winny, Markus
Abstract--In this paper, we quantitatively assess the advantages offered by thick liquid wall (LW) concepts over
.) and is compared to a thick liquid lithium with peak neutron wall load of 10 MW/m2 (7 MW/m2 ave.). "Fixed Radii), the same thick liquid lithium FW is placed in a compact machine with plasma and FW radii reducedAbstract--In this paper, we quantitatively assess the advantages offered by thick liquid wall (LW
California at Los Angeles, University of
Dispersion of torsional waves in a thick-walled transversely isotropic circular cylinder of infinite length
The dispersion properties of torsional waves of a thick-walled transversely isotropic circular cylinder of infinite length are investigated. The assumed waves are axisymmetric and propagate along the x-axis of the cylinder. The wall of the cylinder consists of a transversely isotropic material with the axis of isotropy parallel to the x-axis of the cylinder. The dispersion curves for both the
J. Kudlicka
Delayed primary closure of contaminated abdominal wall defects with non-crosslinked porcine acellular dermal matrix compared with conventional staged repair: a retrospective study
Introduction Synthetic mesh has been used traditionally to repair abdominal wall defects, but its use is limited in the case of bacterial contamination. New biological materials are now being used successfully for delayed primary closure of contaminated abdominal wall defects. The costs of biological materials may prevent surgeons from using them. We compared the conventional staged repair of contaminated abdominal wall defects with a single-stage procedure using a non-crosslinked porcine acellular dermal matrix. Methods A total of 14 cases with Grade 3 contaminated abdominal wall defects underwent delayed primary closure of the abdomen using a non-crosslinked porcine acellular dermal matrix (StratticeÖ Reconstructive Tissue Matrix, LifeCell Corp., Branchburg, NJ, USA). The results were compared with a group of 14 patients who had received conventional treatment for the repair of contaminated abdominal wall defects comprising a staged repair during two separate hospital admissions employing synthetic mesh. Treatment modalities, outcomes, and costs were compared. Results In all cases treated with delayed primary closure employing non-crosslinked porcine acellular dermal matrix, there were no complications related to its use. Two patients died due to unrelated events. Although treatment costs were estimated to be similar in the two groups, the patients treated with porcine acellular dermal matrix spent less time as an inpatient than those receiving conventional two-stage repair. Conclusions Delayed primary closure of contaminated abdominal wall defects using a non-crosslinked porcine acellular dermal matrix may be a suitable alternative to conventional staged repair. In our patients, it resulted in early restoration of abdominal wall function and shorter hospitalization. The costs for treating contaminated abdominal wall defects using porcine acellular dermal matrix during a single hospital admission were not higher than costs for conventional two-stage repair. Further randomized studies are needed to expand upon these findings. PMID:25015374
Cyclodextrin and maltodextrin finishing of a polypropylene abdominal wall implant for the prolonged delivery of ciprofloxacin.
The aim of this work was to develop a polypropylene (PP) artificial abdominal wall implant for the prolonged release of ciprofloxacin (CFX). This sustained release effect was obtained by functionalization of the textile mesh with citric acid and hydroxypropyl-?-cyclodextrin (HP?CD) or maltodextrin (MD). In both cases the textile finishing reaction yielded a cyclo- or malto-dextrin crosslinked polymer coating the fibers. The modified supports were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry and scanning electron microscopy. The sorption capacities and the kinetics of CFX release were studied by batch tests coupled with spectrophotometric assays. Microbiological assays were carried out on Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli, while proliferation and viability tests used fibroblasts. The main results were as follows. (i) Due to the differences between the range of temperature of thermal degradation of the (cyclo)dextrins polymers and of the PP fibers TGA was a reliable method for quantifying the degree of functionalization of the textiles. (ii) Both modified supports showed improved sorption/desorption capacities for CFX, compared with the virgin mesh. The HP?CD-finished support showed an increased sorption capacity and a lower release rate of CFX compared with the MD modified support. (iii) Microbiological assays confirmed the latter result, with greater sustained antibacterial activity of the HP?CD treated support. These experiments have demonstrated the role of the cyclodextrin cavity in interactions with CFX: the antibiotic was not only adsorbed via hydrogen and acid-base interactions with the polyCTR-HP?CD network, but also via host-guest complexation. (iv) Biological tests revealed a slight decrease in fibroblast proliferation after 6 days on the modified supports, but cell viability tests showed that this was not due to toxicity of the (cyclo)dextrin polymer coatings. PMID:21569872
Laurent, T; Kacem, I; Blanchemain, N; Cazaux, F; Neut, C; Hildebrand, H F; Martel, B
Evolution of the wall shear stresses during the progressive enlargement of symmetric Abdominal
29 Chapter 3 Evolution of the wall shear stresses during the progressive enlargement of symmetric stresses acting on the vessel wall. Any structural or conformational wall change has an influence result in altered pressure and wall shear stresses (WSS) and may lead to wall inflammation, thrombus
An exact solution for a thick domain wall in general relativity
NASA Technical Reports Server (NTRS)
An exact solution of the Einstein equations for a static, planar domain wall with finite thickness is presented. At infinity, density and pressure vanish and the space-time tends to the Minkowski vacuum on one side of the wall and to the Taub vacuum on the other side. A surprising feature of this solution is that the density and pressure distribution are symmetric about the central plane of the wall whereas the space-time metric and therefore also the gravitational field experienced by a test particle is asymmetric.
Goetz, Guenter; Noetzold, Dirk
Production of thick-walled hollow glass microspheres for inertial confinement fusion targets by sol-gel technology
To fabricate thick-walled hollow glass microspheres (HGMs) for inertial confinement fusion (ICF) targets by sol-gel technology,\\u000a we investigated the effects of glass composition, blowing agent, refining temperature, pressure and composition of furnace\\u000a atmosphere on the wall thickness of HGMs by numerical simulation and experiments. The results showed that the residence times\\u000a of the thick-walled HGMs in the encapsulating and refining
Cong Gao; XiaoBo Qi; Sheng Wei; ZhanWen Zhang; Bo Li; Tao Shi; QiaoMei Chu
Optimum material distributions for prescribed apparent fracture toughness in thick-walled FGM circular pipes
This study treats the inverse problem of evaluating optimum material distributions intending to realize prescribed apparent fracture toughness in thick-walled functionally graded material (FGM) circular pipes. The incompatible eigenstrain induced in the pipes after cooling from the sintering temperature due to the nonhomogeneous coefficient of thermal expansion is taken into consideration. An approximation method of finding stress intensity factors for
A. M. Afsar; H. Sekine
THICK LIQUID-WALLED, FIELD-REVERSED CONFIGURATION* R. W. Moira
207, Argonne, IL 60439 Abstract A thick flowing layer of liquid (e.g., flibe--a molten salt, or Sn80Li reaction. The surface temperature of the liquid rises as it passes from the inlet nozzles to the exit high with the DT reaction that liquid walls are almost a necessity. Alternatives are to use the D3 He
California at Los Angeles, University of
Pressure induced radial diffusion of a fluid through a thick walled highly elastic cylinder
Radial diffusion of a fluid through a highly elastic thick walled cylinder due to pressure differences at the inner and outer surfaces was considered. The interaction between the fluid diffusion and large solid deformation is accounted for by formulating the problem in the context of the theory of mixtures. The equation for the partial stresses and diffusive body force incorporate
A. S. Wineman; M. Gandhi; D. R. Rajagopal
Ultrasonographic Evaluation of Bowel Wall Thickness and Intramural Blood Flow in Ulcerative Colitis
Aim. This study aimed at assessing Doppler ultrasonographic findings of gut wall vessels and thickness in active and quiescent ulcerative colitis. Methods. Fifty patients with ulcerative colitis were studied using transabdominal grayscale and Doppler sonography of sigmoid, distal and middle parts of descending colon in different stages of the disease. Thickness of colon wall in the most involved site, number of color signals in each box, resistive index (RI), and pulsatility index (PI) were evaluated. Results. The median thickness of the colon wall in the most involved sites was 4.3?mm in acute phase and 4.4?mm in the inactive phase (P = 0.47). The median number of the color signals in the active phase at the most involved site, distal part of descending colon and sigmoid was higher than that of the color signals in the inactive phase (P = 0.0001). In the most involved site, the PI and RI were undetectable in the inactive phase. The median PI was 1.4 in the mild phase, 1.3 in the moderate phase, and 1.1 in the severe phase (P = 0.002). Conclusion. In contrast to the colon wall thickness, increased intramural blood flow reflected the clinical severity in ulcerative colitis patients. PMID:22649739
Bavil, Abolhassan Shakeri; Somi, Mohommad Hossein; Nemati, Masoud; Nadergoli, Batool Seyfi; Ghabili, Kamyar; Mirnour, Reshad; Ashrafi, Hamideh
Fatigue life improvement of an autofrettage thick-walled pressure vessel with an external groove
NASA Astrophysics Data System (ADS)
This report presents an investigation into a fatigue life improvement of an autofrettaged thick-walled pressure vessel with an external groove subjected to pulsating internal pressure, along with mean strain and mean stress effects on strain-controlled low cycle fatigue behavior. Linear elastic stress analysis of an autofrettaged thick-walled pressure vessel with an external groove is done using a finite element method. Autofrettage loading is performed using a thermal loading analogy. Change of external groove geometry is made using a quasi-optimization technique and finite element method to achieve longer fatigue life by relieving the stress concentration at the groove root. Surface treatment using shot peening is employed to produce compressive residual stresses at the vulnerable surface of the groove root to counteract the high tensile stresses. An evaluation of the fatigue life of an autofrettaged thick-walled pressure vessel with an external groove is done through a series of simulation fatigue tests using C-shaped specimens taken from the thick-walled pressure vessel.
Koh, Seung K.; Stephens, Ralph I.
Investigation of the formability limit of aluminium tubes drawn with variable wall thickness
Structural aluminium tubes have very important industrial applications, particularly in automobile industry. Tube drawing process is widely used to reduce the outer and inner diameters of tubes. An important issue in the tube drawing process to obtain variable wall thickness is how to determinate and predict its formability limits. Previously published works generally deal with the formability limit of conventional
Q. H. Bui; R. Bihamta; M. Guillot; G. DÆAmours; A. Rahem; M. Fafard
Roughness effects in a narrow porous journal bearing with arbitrary porous wall thickness
The paper uses Christensen's stochastic theory to study the effects of surface roughness in a narrow porous journal bearing. An exact solution, valid for arbitrary wall thickness, is given for the film pressure and pressure in the bearing material. The results are compared with the approximate solutions, and the range of various influencing parameters, for which the approximate analysis is
K. Gururajan; J. Prakash
Magnet Fall inside a Conductive Pipe: Motion and the Role of the Pipe Wall Thickness
ERIC Educational Resources Information Center
Theoretical models and experimental results are presented for the retarded fall of a strong magnet inside a vertical conductive non-magnetic tube. Predictions and experimental results are in good agreement modelling the magnet as a simple magnetic dipole. The effect of varying the pipe wall thickness on the retarding magnetic drag is studied forģ
Donoso, G.; Ladera, C. L.; Martin, P.
Surgical resection of cerebellar hemangioblastoma with enhanced wall thickness: A report of two cases
Hemangioblastomas are tumors of the central nervous system, and the cerebellum is the most common site of occurrence. Cerebellar hemangioblastoma with enhanced wall thickness is rare and often misdiagnosed preoperatively. At present, no unified radiological classification system based on magnetic resonance imaging (MRI) findings exists for cerebellar hemangioblastoma, and this tumor type can be solid or cystic mass, according to the MRI findings. The most common presentation of cerebellar hemangioblastoma observed radiologically is a large sac with small nodules, where the wall of the large cyst is not enhanced. A tumor with enhanced large cysts and tumor nodules is extremely rare. The most effective treatment is complete resection of the cyst and the solid growth. The present case reports the successful treatment of two cases of cerebellar hemangioblastoma with enhanced wall thickness, including the MRI findings for the differential diagnoses and the surgical experiences.
Sex-Related Differences of Cortical Thickness in Patients with Chronic Abdominal Pain
Background & Aims Regional reductions in gray matter (GM) have been reported in several chronic somatic and visceral pain conditions, including irritable bowel syndrome (IBS) and chronic pancreatitis. Reported GM reductions include insular and anterior cingulate cortices, even though subregions are generally not specified. The majority of published studies suffer from limited sample size, heterogeneity of populations, and lack of analyses for sex differences. We aimed to characterize regional changes in cortical thickness (CT) in a large number of well phenotyped IBS patients, taking into account the role of sex related differences. Methods Cortical GM thickness was determined in 266 subjects (90 IBS [70 predominantly premenopausal female] and 176 healthy controls (HC) [155 predominantly premenopausal female]) using the Laboratory of Neuro Imaging (LONI) Pipeline. A combined region of interest (ROI) and whole brain approach was used to detect any sub-regional and vertex-level differences after removing effects of age and total GM volume. Correlation analyses were performed on behavioral data. Results While IBS as a group did not show significant differences in CT compared to HCs, sex related differences were observed both within the IBS and the HC groups. When female IBS patients were compared to female HCs, whole brain analysis showed significant CT increase in somatosensory and primary motor cortex, as well as CT decrease in bilateral subgenual anterior cingulate cortex (sgACC). The ROI analysis showed significant regional CT decrease in bilateral subregions of insular cortex, while CT decrease in cingulate was limited to left sgACC, accounting for the effect of age and GM volume. Several measures of IBS symptom severity showed significant correlation with CT changes in female IBS patients. Conclusions Significant, sex related differences in CT are present in both HCs and in IBS patients. The biphasic neuroplastic changes in female IBS patients are related to symptom severity. PMID:24040118
Jiang, Zhiguo; Dinov, Ivo D.; Labus, Jennifer; Shi, Yonggang; Zamanyan, Alen; Gupta, Arpana; Ashe-McNalley, Cody; Hong, Jui-Yang; Tillisch, Kirsten; Toga, Arthur W.; Mayer, Emeran A.
Chest wall thickness measurements and the dosimetric implications for male workers in the uranium industry.
The Human Monitoring Laboratory has measured the chest wall thickness and adipose mass fraction of a group of workers at a Canadian uranium refinery, a conversion plant, and a fuel fabrication site using ultrasound. A site-specific biometric equation has been developed for these workers, who seem to be somewhat larger than other workers reported in the literature. Chest wall thickness is a very important modifier on lung counting efficiency and these data have been put into the perspective of the impending Canadian dose limits that will reduce the limit of occupationally exposed workers to 100 mSv in a 5-y period with a maximum of 50 mSv in any one year. The sensitivity of the germanium and phoswich based lung counting systems have been compared. Over a range of chest wall thickness of 1.6 cm to 6.0 cm and using a 30-min counting time, the achievable MDA's lie in the range of 6.7 mg to 19.1 mg or 6.7 mg to 30 mg with a two-phoswich-detector array or a germanium lung counting system, respectively. Depending on chest wall thickness, these achievable MDA's are close to, or exceed, the predicted amounts of natural uranium that will remain in the lung (absorption type M and S) after an intake equivalent to the Annual Limit on Intake that corresponds to 20 mSv. Neither system is sufficiently sensitive to detect an intake of Type S natural uranium in a worker with a chest wall thickness that corresponds to the average (3.73 cm) if it occurred more than 7 d prior to the lung count. PMID:11204122
Kramer, G H; Hauck, B M; Allen, S A
Effects of the Transient Blood Flow-Wall Interaction on the Wall Stress Distribution in Abdominal Aortic Aneurysm (AAA)
NASA Astrophysics Data System (ADS)
Our static finite element analysis (FEA) of both idealized and real clinical models has shown that the maximum diameter and asymmetry have substantial influence on the AAA wall stress distribution. The thrombus inside the AAA was also found to reduce the magnitude of the wall stresses. To achieve a better understanding of the wall stress distribution in real AAAs, a dynamic FEA was also performed. We considered models, both symmetric and non-symmetric, in which the aorta is assumed isotropic with nonlinear material properties. For the limiting case of rigid walls, the evolution of the flow pattern and the wall shear stresses due to fluid flow at different stages of cardiac cycle predicted by our simulations are compared with experimental results obtained in in-vitro models. A good agreement is found between both results. Finally, we have extended the analysis to the physiologically correct case of deformable walls and characterized the transient effects on the wall stresses.
Tang, Rubing; Geindreau, Christian; Lasheras, Juan
Entero-colocutaneous fistula: a late consequence of polypropylene mesh abdominal wall repair: case report and review of the literature
ĀĀ\\u000a \\u000a Background. The underlying risk associated with visceral mesh erosion is the close opposition of adjacent intestines to the prosthetic\\u000a graft. This highly morbid condition has been described with most types and techniques of abdominal wall mesh repair.\\u000a \\u000a \\u000a \\u000a \\u000a Patient. We report the case of a 52-year-old man who presented with an entero-colocutaneous fistula 10Āyears after prosthetic mesh\\u000a repair of an
J. E. Losanoff; B. W. Richman; J. W. Jones
The effect of fig wall thickness in Ficus erecta var. beecheyana on parasitism
NASA Astrophysics Data System (ADS)
Fig wasp communities constitute a model system to analyse determinants of community complexity and to investigate how biological interaction networks are maintained. It has been suggested for monoecious figs, that fig pollinating wasps avoid ovipositing in flowers located close to the fig wall because of strong parasitic pressure by wasps ovipositing through the fig wall. This behaviour could help explain why mainly seeds are produced in flowers located close to the fig wall, thus stabilizing the fig-pollinating wasp mutualism. In this contribution we explore, for dioecious figs, whether ovipositor length of parasitic species may really be limiting. In dioecious figs, functionally male figs produce pollinating wasps and pollen while female figs produce only seeds, facilitating selection of traits favouring pollinator reproduction in male figs. We show in Ficus erecta that fig walls are thicker in male figs than in female figs. Male figs presenting thick walls, thicker than the length of the parasites' ovipositors, went unparasitized while male figs presenting thinner walls were systematically parasitized. Hence, in F. erecta, ovipositor length of the parasites is limiting access to some figs. However, we also show that in another dioecious species, Ficus formosana, presenting thin walled male figs, no fig is protected against oviposition by its two parasites. Hence in dioecious as well as in monoecious figs, in some Ficus species, ovipositors of the parasites are limiting access to ovules, while in other Ficus species all ovules are exposed to parasitism.
Tzeng, Hsy-Yu; Ou, Chern-Hsiung; Lu, Fu-Yuan; Bain, Anthony; Chou, Lien-Siang; Kjellberg, Finn
Abdominal wall hernia and aortic injury secondary to blunt trauma: Case report and review of the literature
INTRODUCTION Traumatic abdominal wall hernia (TAWH) and traumatic abdominal aortic injury (TAAI) are two uncommon complications secondary to blunt trauma. In both TAWH and TAAI, reported cases are often associated with poly-trauma. TAWH may be initially missed if more pressing issues are identified during the patient's primary survey. TAAI may be an incidental finding on imaging or, if severe, a cause of an acute abdomen and hemodynamic abnormality. PRESENTATION OF CASE A 54-year-old white male suffered a TAWH and TAAI (pseudoaneurysm) due to severe blunt trauma. TAWH was apparent on physical exam and the TAAI was suspected on computed tomography (CT). The patient's TAWH was managed with a series of abdominal explorations and the TAAI was repaired with endovascular stenting. DISCUSSION TAWH and TAAI are commonly due to severe blunt trauma from motor vehicle collisions. Diagnosis is made through physical exam, imaging studies, or surgical exploration. A variety of surgical techniques achieve technical success. CONCLUSION The patient with blunt trauma to the abdomen is at risk for TAWH and TAAI, which are often associated with other injuries. Investigations should include thorough clinical exam through secondary survey and radiologic imaging in the hemodynamically normal patient. PMID:25437685
Ballard, David H.; Kaskas, Nadine M.; Hamidian Jahromi, Alireza; Skweres, Justin; Youssef, Asser M.
Separation occurring during the drop weight tear test of thick-walled X80 pipeline steels
NASA Astrophysics Data System (ADS)
A separation phenomenon occurring during the drop weight tear test of commercial thick-walled API (American Petroleum Institute) X80 strip steel was investigated in this work. Microstructural analysis showed that the band structure of bainite elongated along the rolling direction works as the initiation sites of separation. The propagation of separation can be promoted not only by the occurrence of the band structure of martensite/austenite constituent, prior austenite grain boundaries, and elongated bainite, but also by fine acicular ferrite and bainite. Wide separation formed in the former case, while the narrow one appeared in the latter case. Some methods were proposed to obtain fine and homogeneous acicular ferrite in thick-walled X80 pipeline steel in order to minimize the occurrence of separation.
Sha, Qing-yun; Li, Da-hang; Huang, Guo-jian; Guan, Ju
A thermoelastic transversely isotropic thick walled cylinder/disk application: An analytical solution and study
NASA Technical Reports Server (NTRS)
A continuum theory is utilized to represent the thermoelastic behavior of a thick walled composite cylinder that can be idealized as transversely isotropic. A multiaxial statement of the constitutive theory employed is presented, as well as the out of the plane of isotropy, plane stress, and plane strain reductions. The derived analytical solution presented is valid for a cylindrical tube or thin disk with a concentric hole, subjected to internal and/or external pressure and a general radial temperature distribution. A specific problem examined is that of a thick walled cylinder subjected to an internal and external pressure loading and a linear radial temperature distribution. The results are expressed in nondimensional form and the effects on the response behavior are examined for various material properties, fiber orientation and types of loadings.
Arnold, S. M.
Demonstration of Chlamydia pneumoniae in the walls of abdominal aortic aneurysms
Background: Seroepidemiologic studies have indicated an association between chronic Chlamydia pneumoniae infection and coronary heart disease. The organism, which is a common respiratory pathogen, has been demonstrated in atherosclerotic lesions of the aorta and coronary arteries. Abdominal aortic aneurysms are frequently associated with atherosclerosis, and inflammation may actually be an important factor in aneurysmal dilatation. Hence it could be assumed
Jukka Juvonen; Tatu Juvonen; Aino Laurila; Hannu Alakõrppõ; Kari Lounatmaa; Heljõ-Marja Surcel; Maija Leinonen; Matti I. Kairaluoma; Pekka Saikku
Carbon nanotubes as VEGF carriers to improve the early vascularization of porcine small intestinal submucosa in abdominal wall defect repair
Insufficient early vascularization in biological meshes, resulting in limited host tissue incorporation, is thought to be the primary cause for the failure of abdominal wall defect repair after implantation. The sustained release of exogenous angiogenic factors from a biocompatible nanomaterial might be a way to overcome this limitation. In the study reported here, multiwalled carbon nanotubes (MWNT) were functionalized by plasma polymerization to deliver vascular endothelial growth factor165 (VEGF165). The novel VEGF165-controlled released system was incorporated into porcine small intestinal submucosa (PSIS) to construct a composite scaffold. Scaffolds incorporating varying amounts of VEGF165-loaded functionalized MWNT were characterized in vitro. At 5 weight percent MWNT, the scaffolds exhibited optimal properties and were implanted in rats to repair abdominal wall defects. PSIS scaffolds incorporating VEGF165-loaded MWNT (VEGF¢MWNT¢PSIS) contributed to early vascularization from 2¢12 weeks postimplantation and obtained more effective collagen deposition and exhibited improved tensile strength at 24 weeks postimplantation compared to PSIS or PSIS scaffolds, incorporating MWNT without VEGF165 loading (MWNT¢PSIS). PMID:24648727
Liu, Zhengni; Feng, Xueyi; Wang, Huichun; Ma, Jun; Liu, Wei; Cui, Daxiang; Gu, Yan; Tang, Rui
The intricate role of mast cell proteases and the annexin A1-FPR1 system in abdominal wall endometriosis.
Endometriosis is a continuous and progressive disease with a poorly understood aetiology, pathophysiology and natural history. This study evaluated the histological differences between eutopic and ectopic endometria (abdominal wall endometriosis) and the expression of mast cell proteases (tryptase and chymase), annexin A1 (ANXA1) and formyl peptide receptor 1 (FPR1). Ectopic endometrium from 18 women with abdominal wall endometriosis and eutopic endometrium from 10 women without endometriosis were obtained. The endometrial samples were analysed by histopathology, immunohistochemistry and ultrastructural immunogold labeling to determine mast cell heterogeneity (tryptase and chymase positive cells) and the expression levels of ANXA1 and FPR1. Histopathological analysis of the endometriotic lesions showed a glandular pattern of mixed differentiation and an undifferentiated morphology with a significant influx of inflammatory cells and a change in mast cell heterogeneity, as evidenced by a significant increase in the number of chymase-positive cells and endogenous chymase expression. The undifferentiated glandular pattern of endometriotic lesions was positively associated with a marked increase and co-localization of ANXA1 and FPR1 in the epithelial cells. In conclusion, the co-upregulated expression of mast cell chymase and ANXA1-FPR1 system in ectopic endometrium suggests their involvement in the development of endometriotic lesions. PMID:25201101
Paula, Rubens; Oliani, Antonio H; Vaz-Oliani, Denise C M; D'┴vila, Solange C G P; Oliani, Sonia M; Gil, Cristiane D
Blood Vessel Matrix Seeded with Cells: A Better Alternative for Abdominal Wall ReconstructionŚA Long-Term Study
Purpose. The aim of this study was to present abdominal wall reconstruction using a porcine vascular graft seeded with MSC (mesenchymal stem cells) on rat model. Material and Methods. Abdominal wall defect was prepared in 21 Wistar rats. Acellular porcine-vascular grafts taken from aorta and prepared with Triton X were used. 14 aortic grafts were implanted in place, of which 7 grafts were seeded with rat MSC cells (Group I), and 7 were acellular grafts (Group II). As a control, 7 standard polypropylene meshes were used for defect augmentation (Group III). The assessment method was performed by HE and CD31 staining after 6 months. The mechanical properties have been investigated by Zwick&Roell Z0.5. Results. The strongest angiogenesis and lowest inflammatory response were observed in Group I. Average capillaries density was 2.75, 0.75, and 1.53 and inflammatory effect was 0.29, 1.39, and 2.72 for Groups I, II, and III, respectively. The means of mechanical properties were 12.74 ▒ 1.48, 7.27 ▒ 1.56, and 14.4 ▒ 3.7?N/cm in Groups I and II and control, respectively. Conclusions. Cell-seeded grafts have better mechanical properties than acellular grafts but worse than polypropylene mesh. Cells improved mechanical and physiological properties of decellularized natural scaffolds. PMID:25705696
Jundzi??, Arkadiusz; Nazarewski, ?ukasz; Kotela, Andrzej; Kloskowski, Tomasz; Skopi?ska-Wisniewska, Joanna; ?ukasiewicz, Aleksander; Nazarewski, S?awomir; Kotela, Ireneusz; Pokrywczy?ska, Marta; Marsza?ek, Andrzej; Drewa, Tomasz
Blood vessel matrix seeded with cells: a better alternative for abdominal wall reconstruction-a long-term study.
Purpose. The aim of this study was to present abdominal wall reconstruction using a porcine vascular graft seeded with MSC (mesenchymal stem cells) on rat model. Material and Methods. Abdominal wall defect was prepared in 21 Wistar rats. Acellular porcine-vascular grafts taken from aorta and prepared with Triton X were used. 14 aortic grafts were implanted in place, of which 7 grafts were seeded with rat MSC cells (Group I), and 7 were acellular grafts (Group II). As a control, 7 standard polypropylene meshes were used for defect augmentation (Group III). The assessment method was performed by HE and CD31 staining after 6 months. The mechanical properties have been investigated by Zwick&Roell Z0.5. Results. The strongest angiogenesis and lowest inflammatory response were observed in Group I. Average capillaries density was 2.75, 0.75, and 1.53 and inflammatory effect was 0.29, 1.39, and 2.72 for Groups I, II, and III, respectively. The means of mechanical properties were 12.74 ▒ 1.48, 7.27 ▒ 1.56, and 14.4 ▒ 3.7?N/cm in Groups I and II and control, respectively. Conclusions. Cell-seeded grafts have better mechanical properties than acellular grafts but worse than polypropylene mesh. Cells improved mechanical and physiological properties of decellularized natural scaffolds. PMID:25705696
Nowacki, Maciej; Jundzi??, Arkadiusz; Nazarewski, ?ukasz; Kotela, Andrzej; Kloskowski, Tomasz; Skopi?ska-Wisniewska, Joanna; Bodnar, Magdalena; ?ukasiewicz, Aleksander; Nazarewski, S?awomir; Kotela, Ireneusz; Kucharzewski, Marek; Pokrywczy?ska, Marta; Marsza?ek, Andrzej; Drewa, Tomasz
Short- and long-term biomechanical and morphological study of new suture types in abdominal wall closure.
To perform an abdominal-wall closure, a continuous suture is the preferred method. The suture materials that are most commonly employed in abdominal surgery are polypropylene and polydioxanone. However, in recent times, new products have been marketed, such as non-absorbable polyurethane with elastic properties (Assuplus(«), Assut Europe, Italy) and absorbable barbed polydioxanone (Filbloc(«), Assut Europe, Italy). The purpose of this study was to compare the ability of those against the standard polypropylene (Surgipro(TM), Covidien, USA) and polydioxanone (Assufil(«), Assut Europe, Italy) to mimic the biomechanical behavior of the abdominal wall closure. Comparison of the sutures was made first with the materials alone and later in a laparotomy closure of a rabbit abdomen, used as an animal model. The biomechanical analysis consisted of uniaxial tensile tests of threads and sutured samples of the animal abdomen. In the latter case, results were analyzed at short- (21days) and long- (180days) term intervals after the surgery. The morphology studies and collagen expression of the samples were also investigated. The results determined that polydioxanone and polypropylene sutures showed a linear elastic behavior, with barbed polydioxanone as the most compliant suture and polyurethane as the stiffest. The sutured samples showed a statistically significant loss of resistance, measured as the load needed to perform a certain stretch, when compared with the corresponding control tissue. Analysis of the stress-stretch curves showed that elastic polyurethane was the only suture able to reproduce the mechanical behavior of healthy tissue in the short term, while the rest of the sutures remained less stiff. This coincides with the expression of type I collagen observed in this group at this point in the study. In the long term, there was no difference among the sutures, and none was able to mimic control behavior. PMID:24859461
Sim¾n-Alluķ, R; Pķrez-L¾pez, P; Sotomayor, S; Pe±a, E; Pascual, G; Bell¾n, J M; Calvo, B
Detection of gas pipe wall thickness based on electromagnetic flux leakage
Based on electromagnetic flux leakage (EMFL), a nondestructive testing (NDT) technique for the detection of gas pipe wall\\u000a thickness is presented, and its principle and feasibility is evaluated by means of equivalent magnetic circuit analysis and\\u000a finite element analysis. An online NDT device adopting this technique is developed, and its structure and working principle\\u000a are introduced in detail. This device
Yunwei Zhang; Guozheng Yan
Elastoplastic analysis of an internally pressurized thick-walled cylinder using a strain gradient plasticity theory
An analytical solution for the stress, strain and displacement fields in an internally pressurized thick-walled cylinder of an elastic strain-hardening plastic material in the plane strain state is presented. A strain gradient plasticity theory is used to describe the constitutive behavior of the material undergoing plastic deformations, whereas the generalized HookeÆs law is invoked to represent the material response in
X.-L. Gao
White-light interferometric measurement of the wall thickness of hollow glass microspheres
A simple interferometric technique using both a white-light and a monochromatic-light source can be used to measure the wall thickness of hollow glass microspheres to better than 0.05 ?m. The entire procedure requires only a few minutes per sphere and can easily be made to take into account the effects of any gas with which the ball is filled.
Berthold W. Weinstein
White-light interferometric measurement of the wall thickness of hollow glass microspheres
A simple interferometric technique using both a white-light and a monochromatic-light source can be used to measure the wall thickness of hollow glass microspheres to better than 0.05 mum. The entire procedure requires only a few minutes per sphere and can easily be made to take into account the effects of any gas with which the ball is filled.
Berthold W. Weinstein
Effects of selective exercise for the deep abdominal muscles and lumbar stabilization exercise on the thickness of the transversus abdominis and postural maintenance.
[Purpose] The purpose of this study was to examine the effects of selective exercise for the deep abdominal muscles (SEDA) and lumbar stabilization exercise (LSE) on the thickness of the transversus abdominis and postural maintenance on an unstable base of support. [Subjects and Methods] The subjects of this study were 20 male and 10 female adults in their 20s without lumbar pain. They were equally and randomly assigned to a SEDA group and a LSE group. The thickness of the transversus abdominis was measured using ultrasound imaging during rest and drawing-in. The thickness of the transversus abdominis was measured when subjects raised their right and left legs while lying on a Swiss ball. [Results] Initially, there were no differences between the two groups. After the intervention, significant differences were observed in all parameters. A significant interaction between group and period was not found for any parameters. [Conclusion] In conclusion, both SEDA and LSE thickened the transversus abdominis, which is a deep abdominal muscle, thereby adjusting posture, and stabilizing the trunk. These exercises increased the thickness of the deep abdominal muscles. They are important exercises for improving the stability of athletes or patients who need postural adjustment. PMID:25729169
Lee, Jung-Seok; Kim, Tae-Ho; Kim, Da-Yeon; Shim, Jae-Ho; Lim, Jin-Yong
Effects of selective exercise for the deep abdominal muscles and lumbar stabilization exercise on the thickness of the transversus abdominis and postural maintenance
[Purpose] The purpose of this study was to examine the effects of selective exercise for the deep abdominal muscles (SEDA) and lumbar stabilization exercise (LSE) on the thickness of the transversus abdominis and postural maintenance on an unstable base of support. [Subjects and Methods] The subjects of this study were 20 male and 10 female adults in their 20s without lumbar pain. They were equally and randomly assigned to a SEDA group and a LSE group. The thickness of the transversus abdominis was measured using ultrasound imaging during rest and drawing-in. The thickness of the transversus abdominis was measured when subjects raised their right and left legs while lying on a Swiss ball. [Results] Initially, there were no differences between the two groups. After the intervention, significant differences were observed in all parameters. A significant interaction between group and period was not found for any parameters. [Conclusion] In conclusion, both SEDA and LSE thickened the transversus abdominis, which is a deep abdominal muscle, thereby adjusting posture, and stabilizing the trunk. These exercises increased the thickness of the deep abdominal muscles. They are important exercises for improving the stability of athletes or patients who need postural adjustment. PMID:25729169
Lee, Jung-seok; Kim, Tae-ho; Kim, Da-yeon; Shim, Jae-ho; Lim, Jin-yong
Ultrasound Thickness of Bladder Wall in Continent and Incontinent Women and Its Correlation with Cystometry
Objective. To compare bladder wall thickness in two kinds of urinary incontinent womenŚstress urinary incontinence (SUI) and overactive bladder (OAB) with urodynamic detrusor overactivity (DO), and to compare them with continent patients by ultrasound, also, correlate with cystometric results in incontinent women. Methods. 91 women were divided into the following groups: continent (n = 31), SUI (n = 30), and DO (n = 30) groups after clinical evaluation and urodynamic test (only in incontinent women). Transvaginal ultrasound was performed to the bladder wall thickness (BWT) measurement. The mean of BWT was calculated and data were analyzed with ANOVA and Turkey's multiple comparison tests. Pearson's correlation coefficient (r) was used to compare two variables. Receiver operating characteristic (ROC) curve was performed to study BWT as a diagnostic parameter. Results. BWT in DO group was significantly higher than that in the other groups (P < 0.005). A moderate positive correlation was found between BWT and maximum bladder pressure during involuntary bladder contraction. There was no difference in BWT between SUI and continent groups. DO group had lower first desire to void and cystometric capacity. Maximum bladder pressure at detrusor contraction had a moderate positive correlation with BWT. The ROC revealed an area under the curve of 0.962 (95%?CI, 0.90¢1.01). Conclusions. DO patients have increased bladder wall thickness, lower first desire to void, and lower cystometric capacity. There was a moderate correlation between BWT and maximum bladder pressure during involuntary bladder contraction. PMID:25538959
Otsuki, Edney Norio; Oliveira, Emerson; Sartori, Marair Gracio Ferreira; GirŃo, Manoel JoŃo Batista Castelo; Jßrmy-Di Bella, Zsuzsanna Ilona Katalin
Chest wall thickness measurements of the LLNL phantom for small area germanium detector counting.
The Lawrence Livermore National Laboratory (LLNL) phantom was developed to calibrate lung counting systems that are used to estimate plutonium and other low energy photon emitting radionuclides deposited in the lung. Originally, low energy photon counting systems consisted of sodium iodide or phoswich detectors, but they have been largely replaced by smaller germanium detector arrays. The average chest wall thicknesses of the LLNL phantom's torso plate and its overlay plates provided by the manufacturer refer to the regions covered by phoswich detectors; however, germanium detectors are of a different size and are placed in different locations on the phantom's torso plate. Previous work has shown that the manufacturer's data were not applicable for large area germanium detectors. The lung counting system at the Korea Atomic Energy Institute (KAERI) is a small area germanium detector array. Although the detectors are placed within the phoswich circles, only about 25% of the area is covered by the detectors. The LLNL phantom at KAERI has been examined to determine if the manufacturer's data are valid or if new chest wall thickness values must be determined. This paper presents chest wall thickness data for the LLNL phantom with and without its B-series overlay plates at 17 keV, 60 keV, 200 keV, and 1,500 keV and shows that these values are different from the manufacturer's values. PMID:10910393
Kramer, G H; Lee, T Y; Chang, S Y
Free Tensor Fascia Lata Flap and Synthetic Mesh Reconstruction for Full-Thickness Chest Wall Defect
A large full-thickness chest wall defect over 10?cm in diameter requires skeletal reconstruction and soft tissue coverage. Use of various flaps for soft tissue coverage was previously reported, but en bloc resection in each case affects these flap pedicles and sizes. We present a case of a 74-year-old man with a soft tissue tumor involving the left lateral chest wall. We performed an en block resection and skeletal reconstruction using a mesh, free tensor fascia lata (TFL) flap for soft tissue coverage. This procedure could be performed in one position. A fixed fascia lata of the flap was also useful for tight reconstruction with the mesh. We suggest that free TFL and/or anterior lateral thigh flap is a useful technique to reconstruct anterior to posterior lateral chest wall defects. PMID:24191162
Ono, Jumpei; Iyoda, Akira; Matsui, Yoshio; Satoh, Yukitoshi; Uchinuma, Eiju
Assessment of anaesthetic adequacy with upper facial and abdominal wall EMG.
We compared changes in biopotentials arising from upper facial (FEMG) and abdominal (AEMG) muscles associated with alterations in alveolar enflurane concentration and neuromuscular block. Induction of anaesthesia significantly reduced both FEMG and AEMG mean amplitudes (-60% and -43%, respectively). Neuromuscular blocker-induced abolition of the electrically evoked thenar EMG response did not prevent FEMG and/or AEMG activation during endotracheal intubation. Decreasing the alveolar enflurane concentration was associated with an increase in FEMG amplitude prior to visible signs of arousal in half of the patients. Movement and other signs of inadequate anaesthesia were associated with distinct increases in FEMG amplitude in 29 out of 30 patients. Recovery from neuromuscular block during unchanged alveolar enflurane concentration was associated with increasing amplitudes of both FEMG and AEMG. Finally, very low-amplitude FEMG recordings were always associated with relaxed abdominal muscles. PMID:2566482
Paloheimo, M; Edmonds, H L; Wirtavuori, K; Tammisto, T
Accurate measurement of respiratory airway wall thickness in CT images using a signal restoration technique
NASA Astrophysics Data System (ADS)
Airway wall thickness (AWT) is an important bio-marker for evaluation of pulmonary diseases such as chronic bronchitis, bronchiectasis. While an image-based analysis of the airway tree can provide precise and valuable airway size information, quantitative measurement of AWT in Multidetector-Row Computed Tomography (MDCT) images involves various sources of error and uncertainty. So we have developed an accurate AWT measurement technique for small airways with three-dimensional (3-D) approach. To evaluate performance of these techniques, we used a set of acryl tube phantom was made to mimic small airways to have three different sizes of wall diameter (4.20, 1.79, 1.24 mm) and wall thickness (1.84, 1.22, 0.67 mm). The phantom was imaged with MDCT using standard reconstruction kernel (Sensation 16, Siemens, Erlangen). The pixel size was 0.488 mm ū 0.488 mm ū 0.75 mm in x, y, and z direction respectively. The images were magnified in 5 times using cubic B-spline interpolation, and line profiles were obtained for each tube. To recover faithful line profile from the blurred images, the line profiles were deconvolved with a point spread kernel of the MDCT which was estimated using the ideal tube profile and image line profile. The inner diameter, outer diameter, and wall thickness of each tube were obtained with full-width-half-maximum (FWHM) method for the line profiles before and after deconvolution processing. Results show that significant improvement was achieved over the conventional FWHM method in the measurement of AWT.
Park, Sang Joon; Kim, Tae Jung; Kim, Kwang Gi; Lee, Sang Ho; Goo, Jin Mo; Kim, Jong Hyo
Distinct defects in collagen microarchitecture underlie vessel-wall failure in advanced abdominal aneurysms and aneurysms in Marfan syndrome.
An aneurysm of the aorta is a common pathology characterized by segmental weakening of the artery. Although it is generally accepted that the vessel-wall weakening is caused by an impaired collagen metabolism, a clear association has been demonstrated only for rare syndromes such as the vascular type Ehlers-Danlos syndrome. Here we show that vessel-wall failure in growing aneurysms of patients who have aortic abdominal aneurysm (AAA) or Marfan syndrome is not related to a collagen defect at the molecular level. On the contrary our findings indicate similar (Marfan) or even higher collagen concentrations (AAA) and increased collagen cross-linking in the aneurysms. Using 3D confocal imaging we show that the two conditions are associated with profound defects in collagen microarchitecture. Reconstructions of normal vessel wall show that adventitial collagen fibers are organized in a loose braiding of collagen ribbons. These ribbons encage the vessel, allowing the vessel to dilate easily but preventing overstretching. AAA and aneurysms in Marfan syndrome show dramatically altered collagen architectures with loss of the collagen knitting. Evaluations of the functional characteristics by atomic force microscopy showed that the wall has lost its ability to stretch easily and revealed a second defect: although vascular collagen in normal aortic wall behaves as a coherent network, in AAA and Marfan tissues it does not. As result, mechanical forces loaded on individual fibers are not distributed over the tissue. These studies demonstrate that the mechanical properties of tissue are strongly influenced by collagen microarchitecture and that perturbations in the collagen networks may lead to mechanical failure. PMID:20080766
Lindeman, Jan H N; Ashcroft, Brian A; Beenakker, Jan-Willem M; van Es, Maarten; Koekkoek, Nico B R; Prins, Frans A; Tielemans, Jarl F; Abdul-Hussien, Hazem; Bank, Ruud A; Oosterkamp, Tjerk H
Inverse Transient Analysis for Classification of Wall Thickness Variations in Pipelines
Analysis of transient fluid pressure signals has been investigated as an alternative method of fault detection in pipeline systems and has shown promise in both laboratory and field trials. The advantage of the method is that it can potentially provide a fast and cost effective means of locating faults such as leaks, blockages and pipeline wall degradation within a pipeline while the system remains fully operational. The only requirement is that high speed pressure sensors are placed in contact with the fluid. Further development of the method requires detailed numerical models and enhanced understanding of transient flow within a pipeline where variations in pipeline condition and geometry occur. One such variation commonly encountered is the degradation or thinning of pipe walls, which can increase the susceptible of a pipeline to leak development. This paper aims to improve transient-based fault detection methods by investigating how changes in pipe wall thickness will affect the transient behaviour of a system; this is done through the analysis of laboratory experiments. The laboratory experiments are carried out on a stainless steel pipeline of constant outside diameter, into which a pipe section of variable wall thickness is inserted. In order to detect the location and severity of these changes in wall conditions within the laboratory system an inverse transient analysis procedure is employed which considers independent variations in wavespeed and diameter. Inverse transient analyses are carried out using a genetic algorithm optimisation routine to match the response from a one-dimensional method of characteristics transient model to the experimental time domain pressure responses. The accuracy of the detection technique is evaluated and benefits associated with various simplifying assumptions and simulation run times are investigated. It is found that for the case investigated, changes in the wavespeed and nominal diameter of the pipeline are both important to the accuracy of the inverse analysis procedure and can be used to differentiate the observed transient behaviour caused by changes in wall thickness from that caused by other known faults such as leaks. Further application of the method to real pipelines is discussed.
Tuck, Jeffrey; Lee, Pedro
Controlled protein release from monodisperse biodegradable double-wall microspheres of controllable shell thickness
Biodegradable polymer microparticles are promising delivery depots for protein therapeutics due to their relatively simple fabrication and facile administration. Double-wall microspheres (DWMS) comprising a core and shell made of two distinct polymers may provide enhanced control of the drug release profiles. Using precision particle fabrication (PPF) technology, monodisperse DWMS were fabricated with model protein bovine serum albumin (BSA)-loaded poly(lactide-co-glycolide) (PLG) core and drug-free poly(d,l-lactic acid) (PDLL) shell of uniform thickness. Monolithic single-wall microspheres were also fabricated to mimic the BSA-loaded PLG core. Using ethyl acetate and dichloromethane as shell- and core-phase solvents, respectively, BSA was encapsulated selectively in the core region within DWMS with higher loading and encapsulation efficiency compared to using dichloromethane as core and shell solvents. BSA in vitro release rates were retarded by the presence of the drug-free PDLL shell. Moreover, increasing PDLL shell thickness resulted in decreasing BSA release rate. With a 14-Ąm thick PDLL shell, an extended period of constant-rate release was achieved. PMID:23954731
Xia, Yujie; Ribeiro, Pedro F.; Pack, Daniel W.
Growth and Remodeling in a Thick-Walled Artery Model: Effects of Spatial Variations in Wall Constituents
A mathematical model is presented for growth and remodeling of arteries. The model is a thick-walled tube composed of a constrained mixture of smooth muscle cells, elastin and collagen. Material properties and radial and axial distributions of each constituent are prescribed according to previously published data. The analysis includes stress-dependent growth and contractility of the muscle and turnover of collagen fibers. Simulations were conducted for homeostatic conditions and for the temporal response following sudden hypertension. Numerical pressure-radius relations and opening angles (residual stress) show reasonable agreement with published experimental results. In particular, for realistic material and structural properties, the model predicts measured variations in opening angles along the length of the aorta with reasonable accuracy. These results provide a better understanding of the determinants of residual stress in arteries and could lend insight into the importance of constituent distributions in both natural and tissue-engineered blood vessels. PMID:17786493
Alford, Patrick W.; Humphrey, Jay D.; Taber, Larry A.
Radical cystectomy and pelvic lymphadenectomy with ileal conduit urinary diversion and abdominal wall reconstruction: an interesting case of multidisciplinary management
The ileal conduit for urinary diversion after radical cystectomy is a well-described procedure. Furthermore, parastomal hernias, prolapse, stenosis, and retraction of the stoma have been reported as some of the more common complications of this procedure. The subsequent repair of parastomal hernias with a biological mesh and the potential of the conduit to ōtunnelö through it has also been described. In this case report, we present a combined repair of a large incisional hernia with a cystectomy and a pelvic lymphadenectomy for invasive bladder cancer, with the use of a biological mesh for posterior component abdominal wall primary repair as well as for support to the ileal conduit used for urinary diversion. PMID:25653561
Sofos, Stratos S; Walsh, Ciaran J; Parr, Nigel J; Hancock, Kevin
Heterogeneous atrial wall thickness and stretch promote scroll waves anchoring during atrial fibrillation
Aims Atrial dilatation and myocardial stretch are strongly associated with atrial fibrillation (AF). However, the mechanisms by which the three-dimensional (3D) atrial architecture and heterogeneous stretch contribute to AF perpetuation are incompletely understood. We compared AF dynamics during stretch-related AF (pressure: 12cmH2O) in normal sheep hearts (n = 5) and in persistent AF (PtAF, n = 8)-remodelled hearts subjected to prolonged atrial tachypacing. We hypothesized that, in the presence of stretch, meandering 3D atrial scroll waves (ASWs) anchor in regions of large spatial gradients in wall thickness. Methods and results We implemented a high-resolution optical mapping set-up that enabled simultaneous epicardial- and endoscopy-guided endocardial recordings of the intact atria in Langendorff-perfused normal and PtAF (AF duration: 21.3 ▒ 11.9 days) hearts. The numbers and lifespan of long-lasting ASWs (>3 rotations) were greater in PtAF than normal (lifespan 0.9 ▒ 0.5 vs. 0.4 ▒ 0.2 s/(3 s of AF), P< 0.05). Than normal hearts, focal breakthroughs interacted with ASWs at the posterior left atrium and left atrial appendage to maintain AF. In PtAF hearts, ASW filaments seemed to span the atrial wall from endocardium to epicardium. Numerical simulations using 3D atrial geometries (Courtemanche-Ramirez-Nattel human atrial model) predicted that, similar to experiments, filaments of meandering ASWs stabilized at locations with large gradients in myocardial thickness. Moreover, simulations predicted that ionic remodelling and heterogeneous distribution of stretch-activated channel conductances contributed to filament stabilization. Conclusion The heterogeneous atrial wall thickness and atrial stretch, together with ionic and anatomic remodelling caused by AF, are the main factors allowing ASW and AF maintenance. PMID:22227155
Yamazaki, Masatoshi; Mironov, Sergey; Taravant, Clķment; Brec, Julien; Vaquero, Luis M.; Bandaru, Krishna; Avula, Uma Mahesh R; Honjo, Haruo; Kodama, Itsuo; Berenfeld, Omer; Kalifa, Jķr¶me
IFE thick liquid wall chamber dynamics: Governing mechanisms andmodeling and experimental capabilities
For thick liquid wall concepts, it is important to understand the different mechanisms affecting the chamber dynamics and the state of the chamber prior to each shot a compared with requirements from the driver and target. These include ablation mechanisms, vapor transport and control, possible aerosol formation, as well as protective jet behavior. This paper was motivated by a town meeting on this subject which helped identify the major issues, assess the latest results, review the capabilities of existing modeling and experimental facilities with respect to addressing remaining issues, and helping guide future analysis and R&D efforts; the paper covers these exact points.
Raffray, A.R.; Meier, W.; Abdel-Khalik, S.; Bonazza, R.; Calderoni, P.; Debonnel, C.S.; Dragojlovic, Z.; El-Guebaly, L.; Haynes,D.; Latkowski, J.; Olson, C.; Peterson, P.F.; Reyes, S.; Sharpe, P.; Tillack, M.S.; Zaghloul, M.
The effect of abdominal wall morphology on ultrasonic pulse distortion. Part I. Measurements
than for fat layers. ® 1998 Acoustical Society of America. S0001-4966 98 05911-6 PACS numbers: 43.80.Cs is that poor ultrasonic image quality is primarily associated with obesity.1Ł3 Although this belief has some to obesity in general, that is, that image quality depends on the individual's body wall struc- ture
Mast, T. Douglas
Effect of thick horizontal partial partition attached to one of the active walls of a differentially heated square cavity
The effect of a partial horizontal partition plate of finite thickness, attached to the heated vertical wall of a differentially heated square cavity, has been studied numerically using the finite element method. The partition thickness is varied from 0.5% of the height of the cavity to 10%. The partition is considered to be located at the middle of the hot wall of a width equivalent to 20% of the cavity width. It is observed that as the partition thickness is reduced, heat transfer across the cavity decreases at first, until a critical thickness of the partition plate is reached. Beyond this value, heat transfer increases as the thickness of the partition is further reduced. Streamline maps are found to be notably sensitive to the partition thickness. The effect of conductivity of the partition material on heat transfer is also studies. Except for material with poor thermal properties, conductivity of the partition is observed to have a negligible effect on heat transfer.
Nag, A.; Sarkar, A. (Jadavpur Univ., Calcutta (India). Dept. of Mechanical Engineering); Sastri, V.M.K. (Indian Inst. of Technology, Madras (India). Dept. of Mechanical Engineering)
Quantitation of thick-walled peripheral lung vessels in chronic airways obstruction.
The number of thick-walled peripheral lung vessels (defined as vessels of less than 100 mu diameter with two distinct elastic laminae) was calculated in 50 postmortem lungs. The size of the right ventricle, the amount and type of emphysema, and the proportion of small airways lumen in the lung were also quantitated. Eighteen patients had died as a result of chronic airways obstruction, 17 had symptoms of chronic chest disease but died from some unrelated cause, and 15 had no symptoms related to the respiratory system. The mean number of thick-walled peripheral lung vessels (TWPV) was found to be significantly greater in the fatal disease group than in both of the other groups. No significant difference was found between the mean values of the symptomatic and asymptomatic groups. The mean number of TWPV was significantly greater in cases with a right ventricular weight of more than 80 g than in those with a weight of less than 65 g. Positive correlations were found between the number of TWPV and right ventricular weight, total amount of emphysema in the lung, and the amounts of centrilobular and panlobular emphysema. Significant negative correlations were found between the number of TWPV and both the ratio of the weight of the left ventricle to the right ventricle and the proportion of small airways lumen in the lung. PMID:941117
Scott, K W
Rolled-up optical microcavities with subwavelength wall thicknesses for enhanced liquid sensing applications.
Microtubular optical microcavities from rolled-up ring resonators with subwavelength wall thicknesses have been fabricated by releasing prestressed SiO/SiO(2) bilayer nanomembranes from photoresist sacrificial layers. Whispering gallery modes are observed in the photoluminescence spectra from the rolled-up nanomembranes, and their spectral peak positions shift significantly when measurements are carried out in different surrounding liquids, thus indicating excellent sensing functionality of these optofluidic microcavities. Analytical calculations as well as finite-difference time-domain simulations are performed to investigate the light confinement in the optical microcavities numerically and to describe the experimental mode shifts very well. A maximum sensitivity of 425 nm/refractive index unit is achieved for the microtube ring resonators, which is caused by the pronounced propagation of the evanescent field in the surrounding media due to the subwavelength wall thickness design of the microcavity. Our optofluidic sensors show high potential for lab-on-a-chip applications, such as real-time bioanalytic systems. PMID:20527797
Huang, Gaoshan; Bola±os Qui±ones, Vladimir A; Ding, Fei; Kiravittaya, Suwit; Mei, Yongfeng; Schmidt, Oliver G
Dissipative particle dynamics study of relationship between wall thickness and size in polymer vesicles
NASA Astrophysics Data System (ADS)
Vesicles and membrane properties have long been thought to be essential for reproducing the natural environment of living cells. By using dissipative particle dynamics method, we have studied the relationship between wall thickness and size of vesicles obtained from A1BnA1 block copolymers, where block A is hydrophilic and block B is hydrophobic. Our findings suggest that, the wall thickness is sensitive to the size of vesicles at a low block length ratio of B/A, but insensitive to the size at a large ratio. It shows both weak and strong effects with a crossover point in between. These behaviors are consistent with the experimental results of Eisenberg and co-workers. Besides, an additional crossover point also has been observed. With the B/A ratio increases, the relationship goes from strong to weak behavior, and this transformation first appears to affect the outer area for large sized vesicles, and then to the inner area for small sized vesicles. These results may also be useful in delivery applications through controlling the hydrophobic membrane and the hydrophilic coronas.
Xiao, Mengying; Wang, Rong; Xie, Daiqian
Quantitative Analysis of Intraventricular Dyssynchrony Using Wall Thickness by Multidetector Computed Tomography
OBJECTIVES We sought to determine the feasibility of cardiac computed tomography (CT) to detect significant differences in the extent of left ventricular dyssynchrony in heart failure (HF) patients with wide QRS, HF patients with narrow QRS, and age-matched controls. BACKGROUND The degree of mechanical dyssynchrony has been suggested as a predictor of response to cardiac resynchronization therapy. There have been no published reports of dyssynchrony assessment with the use of CT. METHODS Thirty-eight subjects underwent electrocardiogram-gated contrast-enhanced 64-slice multidetector CT. The left ventricular endocardial and epicardial boundaries were delineated from short-axis images reconstructed at 10% phase increments of the cardiac cycle. Global and segmental CT dyssynchrony metrics that used changes in wall thickness, wall motion, and volume over time were assessed for reproducibility. We defined a global metric using changes in wall thickness as the dyssynchrony index (DI). RESULTS The DI was the most reproducible metric (interobserver and intraobserver intraclass correlation coefficients ?0.94, p < 0.0001) and was used to determine differences between the 3 groups: HF-wide QRS group (ejection fraction [EF] 22 ▒ 8%, QRS 163 ▒ 28 ms), HF-narrow QRS (EF 26 ▒ 7%, QRS 96 ▒ 11 ms), and age-matched control subjects (EF 64 ▒ 5%, QRS 87 ▒ 9 ms). Mean DI was significantly different between the 3 groups (HF-wide QRS: 152 ▒ 44 ms, HF-narrow QRS: 121 ▒ 58 ms, and control subjects: 65 ▒ 12 ms; p < 0.0001) and greater in the HF-wide QRS (p < 0.0001) and HF-narrow QRS (p = 0.005) groups compared with control subjects. We found that DI had a good correlation with 2-dimensional (r = 0.65, p = 0.012) and 3-dimensional (r = 0.68, p = 0.008) echocardiographic dyssynchrony. CONCLUSIONS Quantitative assessment of global CT-derived DI, based on changes in wall thickness over time, is highly reproducible and renders significant differences between subjects most likely to have dyssynchrony and age-matched control subjects. PMID:19212461
Truong, Quynh A.; Singh, Jagmeet P.; Cannon, Christopher P.; Sarwar, Ammar; Nasir, Khurram; Auricchio, Angelo; Faletra, Francesco F.; Sorgente, Antonio; Conca, Cristina; Moccetti, Tiziano; Handschumacher, Mark; Brady, Thomas J.; Hoffmann, Udo
[Local injection of BRM-activated killer cells into an abdominal wall tumor].
Based on the concept of living with cancer, wherein the goal is to help patients with highly advanced solid cancers maintain a high quality of life(QOL)without adverse events and drug resistance, we developed a new immunocyte therapy based on BRM-activated killer(BAK)cells, which are primarily CD56 positive lymphocytes. In a previous report, we documented the disappearance of liver metastases, as assessed by positron emission tomography-computed tomography(PET-CT), in patients with metastatic liver cancers into which BAK immunocytes had been administered via injection into the hepatic artery. Herein, upon the patient's request, we locally injected BAK lymphocytes into an abdominal tumor. In BAK therapy, 20 mL of peripheral blood are collected from a patient. Lymphocytes from this blood sample are subsequently activated and multiplied with immobilized anti-CD3 antibodies and IL-2 and are cultured for 2 weeks with E(bina)and serum-free ALys media to yield approximately 10 billion autologous lymphocytes. On the final day of incubation, the lymphocytes are treated with 1,000 units/mL of interferon(IFN)-a for 15 minutes to enhance their therapeutic killing effects. During the second week, approximately 10 billion isolated autologous lymphocytes are suspended in 200 mL of Ringer's solution and are then drip-infused into the patient over a period of 1 hour. We injected approximately 10 billion BAK lymphocytes suspended in 50 mL of Ringer's solution into a 2-cm abdominal tumor in a single 60-year-old woman under ultrasonography guidance. This procedure was repeated every 3 weeks. After the third administration, we collected a biopsy specimen and examined it using PAS staining and microscopy. The 3 separate local injections of approximately 10 billion activated autologous lymphocytes each, primarily CD56 positive cells, into the tumor led to tumor fragmentation, leaving approximately 10 lymphocytes surrounding each cancer cell. These results suggest that BAK therapy is efficacious and show that locally administered BAK lymphocytes can reach cancer tissues and effectively kill cancer cells. PMID:24231704
Ebina, Takusaburo
Changes in the wall shear stresses (WSS) during the enlargement of Abdominal Aortic Aneurysms (AAA)
NASA Astrophysics Data System (ADS)
The changes in the evolution of the spatial and temporal distribution of the WSS and gradients of WSS at different stages of the enlargement of AAAs are important to understand the etiology and progression of this vascular disease, since they affect the wall structural integrity, primarily via the changes induced on the shape, functions and metabolism of the endothelial cells. PIV measurements were performed in aneurysm models, while changing systematically their geometric parameters. We show that, even at very early stages of the disease (dilatation > 30%), the flow separates from the wall and the formation of a large vortex ring followed by internal shear layers leads to the generation of WSS that drastically differ from the healthy vessel. Inside the AAA, the mean WSS decreases to zero and the magnitude of the WSS can be as low as 26% of the value in a healthy vessel. Two regions with distinct patterns of WSS were identified. The region of flow detachment, with oscillatory WSS of very low mean, and the region of flow reattachment, located distally, where large, negative WSS and sustained gradients of WSS are produced as a result of the impact of the vortex ring on the wall.
Salsac, Anne-Virginie; Sparks, Steven R.; Chomaz, Jean-Marc; Lasheras, Juan C.
The relationship between bladder wall thickness and lower urinary tract symptoms: Does bladder wall thickness change after alpha-blocker therapy with alfuzosin?
Introduction: We evaluate the association between lower urinary tract symptoms (LUTS) and bladder wall thickness (BWT) and investigate whether alfuzosin might improve BWT. Methods: We retrospectively reviewed the data of 164 patients with LUTS. Patients were divided into 2 groups according to BWT (Group 1: BWT ?5 mm, n = 69; Group 2: BWT >5 mm, n = 95). Age, international prostate symptom score (IPSS), maximum and average urinary flow rates (Qmax and Qave), quality of life (QoL), postvoid residual (PVR) urine volume, prostate volume and prostate-specific antigen (PSA) were compared between the 2 groups. In total, 102 patients underwent transurethral resection of the prostate (TURP) and 62 patients were treated with alfuzosin. We compared BWT, Qmax, Qave, IPSS, QoL, PVR and PSA before and at the sixth month of alfuzosin therapy. A p value of <0.05 was considered statistically significant. Results: The mean BWT of Group 1 was 3.72 ▒ 0.56 mm and Group 2 was 6.43 ▒ 1.13 mm. There was a significant difference between the 2 groups in terms of mean Qmax and PVR. There was no statistical difference between the groups in terms of Qave, IPSS, QoL, prostate volume and PSA. There was significant difference between BWT before (6.8 ▒ 2.1) and after (4.6 ▒ 1.3) treatment with alfuzosin in 62 patients (p = 0.02). There was a significant difference between pre- and post-treatment values of mean Qmax, Qave, IPSS, QoL score, and PVR with alfuzosin. Conclusion: BWT is a non-invasive and effective test to evaluate patients with lower urinary tract obstruction and may be used for showing the effectiveness of alpha-blocker therapy in patients with LUTS. PMID:24454597
Karakose, Ayhan; Aydogdu, Ozgu; Atesci, Yusuf Ziya
Effects of chitosan coatings on polypropylene mesh for implantation in a rat abdominal wall model.
Hernia repair and pelvic floor reconstruction are usually accompanied with the implantation of a surgical mesh, which frequently results in a foreign body response with associated complications. An ideal surgical mesh that allows force generation of muscle tissues without significant granulation tissue and/or fibrosis is of significant clinical interest. The objective of the present study was to evaluate the in vitro and in vivo responses of a chitosan coating on polypropylene mesh (Ch-PPM) in comparison with commercially available meshes. We found that application of a 0.5% (w/v) Ch-PPM elicited preferential attachment of myoblasts over fibroblast attachment in vitro. Therefore, we test the hypothesis that 0.5% Ch-PPM will encourage skeletal muscle tissue ingrowth and decrease fibrosis formation in vivo. We implanted 0.5% Ch-PPM, collagen-coated polypropylene mesh (PelvitexÖ; C.R. Bard), and polypropylene (Avaulta Solo(«); C.R. Bard) alone using a rat abdominal defect model. Force generation capacity and inflammatory response of each mesh were evaluated 2, 4, and 12 weeks postimplantation. We found that chitosan coating is associated with the restoration of functional skeletal muscle with histomorphologic characteristics that resemble native muscle and an early macrophage phenotypic response that has previously been shown to lead to more functional outcomes. PMID:23859182
Udpa, Natasha; Iyer, Shama R; Rajoria, Rohit; Breyer, Kate E; Valentine, Helen; Singh, Bhupinder; McDonough, Sean P; Brown, Bryan N; Bonassar, Lawrence J; Gao, Yingxin
Effects of Chitosan Coatings on Polypropylene Mesh for Implantation in a Rat Abdominal Wall Model
Hernia repair and pelvic floor reconstruction are usually accompanied with the implantation of a surgical mesh, which frequently results in a foreign body response with associated complications. An ideal surgical mesh that allows force generation of muscle tissues without significant granulation tissue and/or fibrosis is of significant clinical interest. The objective of the present study was to evaluate the in vitro and in vivo responses of a chitosan coating on polypropylene mesh (Ch-PPM) in comparison with commercially available meshes. We found that application of a 0.5% (w/v) Ch-PPM elicited preferential attachment of myoblasts over fibroblast attachment in vitro. Therefore, we test the hypothesis that 0.5% Ch-PPM will encourage skeletal muscle tissue ingrowth and decrease fibrosis formation in vivo. We implanted 0.5% Ch-PPM, collagen-coated polypropylene mesh (PelvitexÖ; C.R. Bard), and polypropylene (Avaulta Solo«; C.R. Bard) alone using a rat abdominal defect model. Force generation capacity and inflammatory response of each mesh were evaluated 2, 4, and 12 weeks postimplantation. We found that chitosan coating is associated with the restoration of functional skeletal muscle with histomorphologic characteristics that resemble native muscle and an early macrophage phenotypic response that has previously been shown to lead to more functional outcomes. PMID:23859182
Udpa, Natasha; Iyer, Shama R.; Rajoria, Rohit; Breyer, Kate E.; Valentine, Helen; Singh, Bhupinder; McDonough, Sean P.; Brown, Bryan N.; Bonassar, Lawrence J.
Airway wall thickness is increased in COPD patients with bronchodilator responsiveness
Rationale Bronchodilator responsiveness (BDR) is a common but variable phenomenon in COPD. The CT characteristics of airway dimensions that differentiate COPD subjects with BDR from those without BDR have not been well described. We aimed to assess airway dimensions in COPD subjects with and without BDR. Methods We analyzed subjects with GOLD 1¢4 disease in the COPDGene« study who had CT airway analysis. We divided patients into two groups: BDR?+?(post bronchodilator ?FEV1???10%) and BDR-(post bronchodilator ?FEV1?10%). The mean wall area percent (WA%) of six segmental bronchi in each subject was quantified using VIDA. Using 3D SLICER, airway wall thickness was also expressed as the square root wall area of an airway of 10Āmm (Pi10) and 15Āmm (Pi15) diameter. %Emphysema and %gas trapping were also calculated. Results 2355 subjects in the BDR-group and 1306 in the BDR?+?group formed our analysis. The BDR?+?group had a greater Pi10, Pi15, and mean segmental WA% compared to the BDR-group. In multivariate logistic regression using gender, race, current smoking, history of asthma, %emphysema, %gas trapping, %predicted FEV1, and %predicted FVC, airway wall measures remained independent predictors of BDR. Using a threshold change in FEV1???15% and FEV1???12% and 200ĀmL to divide patients into groups, the results were similar. Conclusion BDR in COPD is independently associated with CT evidence of airway pathology. This study provides us with greater evidence of changes in lung structure that correlate with physiologic manifestations of airflow obstruction in COPD. PMID:25248436
A method of computing the transient temperature of thick walls from arbitrary variation of adiabatic-wall temperature and heat-transfer coefficient
NASA Technical Reports Server (NTRS)
A method of calculating the temperature of thick walls has been developed in which the time series and the response to a unit triangle variation of surface temperature concepts are used, together with essentially standard formulas for transient temperature and heat flow into thick walls. The method can be used without knowledge of the mathematical tools of its development. The method is particularly suitable for determining the wall temperature in one-dimensional thermal problems in aeronautics where there is a continuous variation of the heat-transfer coefficient and adiabatic-wall temperature. The method also offers a convenient means for solving the inverse problem of determining the heat-flow history when temperature history is known.
Hill, P R
Residual stress analysis in forming process of filament wound thick-walled CFRP pipes
Residual stress analysis for the cracking phenomenon of filament would thick-walled CFRP pipes, which frequently occurs in the forming process of curing and thermal cycling through the course of the wet filament winding, was made from both the experimental and theoretical points of view. A simple analytical model to study the cracking in the CFRP pipes was proposed. The pipes are multilayered and reinforced in the axial and circumferential directions alternatively by carbon fibers. Taking account of the anisotropy of mechanical and thermal properties including the shrinkage strain, which depend considerably on the temperature, the residual stresses in the CFRP pipes were elucidated in the forming process, particularly, in cooling of the cure process.
Kondo, Toshimi [Nagaoka College of Technology (Japan). Dept. of Mechanical Engineering; Sekine, Hideki [Tohoku Univ., Sendai (Japan). Dept. of Aeronautics and Space Engineering; Nakano, Kunio [Japan Space Utilization Center, Tokyo (Japan)
Release of small hydrophilic molecules from polyelectrolyte capsules: Effect of the wall thickness.
Polymer nanocapsules assembled on cationic liposomes have been built through the layer-by-layer (LbL) technique. Chitosan and alginate, two biocompatible polyelectrolytes, were used to cover the template, where the Rhodamine B was previously loaded. The multishell formed with the alternate deposition of the polyelectrolytes, according to the principles of the LbL assembly, was supposed to change the permeability of the capsule wall. The thickness of the multishell was seen increasing with the number of layers deposited through the observations with the Transmission Electron Microscope. The permeability of the capsules was studied through Rhodamine B release assays. Nanocapsules with seven layers of polyelectrolytes released the dye slowly compared to the capsules with three or five layers. The Ritger-Peppas model was applied to investigate the release mechanisms and a non-Fickian transport behavior was detected regardless of the number of layers. Values of diffusion coefficients of Rhodamine B through the capsule wall were also calculated. PMID:25465199
Cuomo, Francesca; Lopez, Francesco; Piludu, Marco; Miguel, Maria G; Lindman, Bjorn; Ceglie, Andrea
Erratum: ``Simulation of ultrasonic pulse propagation through the abdominal wall'' [J. Acoust. Soc. Am. 102,
.000 120fe 28┬Ł30 Exp. 73.8 8.66 3.66 3.71 0.914 FDTD 67.1 8.19 3.41 1.30 0.983 S-R 71.3 8.72 0.51 6.11 1-ray simulations S-R . Arrival time fluctuations Energy level fluctuations Specimen number Specimen thickness mm factor 75hi 31┬Ł34 Exp. 92.7 4.10 3.85 2.99 0.873 FDTD 53.0 4.70 3.29 1.25 0.957 S-R 62.3 2.40 0.42 1.92 1
Mast, T. Douglas
Time-dependent creep stress redistribution analysis of thick-walled functionally graded spheres
NASA Astrophysics Data System (ADS)
Time-dependent creep stress redistribution analysis of thick-walled spheres made of functionally graded material (FGM) subjected to an internal pressure and a uniform temperature field is performed using the method of successive elastic solution. The material creep and mechanical properties through the radial graded direction are assumed to obey a simple power-law variation. Total strains are assumed to be the sum of elastic, thermal and creep strains. Creep strains are time, temperature and stress dependent. Using the equations of equilibrium, compatibility and stress-strain relations a differential equation, containing creep strains, for radial stress are obtained. Ignoring creep strains, a closed-form solution for initial thermoelastic stresses at zero time is presented. It has been found that the material in-homogeneity parameter ? has a substantial effect on thermoelastic stresses. From thermoelastic analysis the material identified by ?=2 in which a more uniform shear stress distribution occurs throughout the thickness of the FGM sphere is selected for time-dependent stress redistribution analysis. Using the Prandtl-Reuss relations and Norton's creep constitutive model, history of stresses and strains are obtained. It has been found that radial stress redistributions are not significant, however, major redistributions occur for circumferential and effective stresses. It has also been concluded that stresses and strains are changing with time at a decreasing rate so that there is a saturation condition beyond which not much change occurs. Indeed after 50 years the solution approaches the steady-state condition.
Loghman, A.; Ghorbanpour Arani, A.; Aleayoub, S. M. A.
Risk factors associated with early failure in complex abdominal wall reconstruction: A 5 year single surgeon experience.
Complex abdominal wall reconstruction (AWR) is commonly performed, but with a significant rate of surgical complications and hernia recurrence. The aim of this experiential review is to assess risk factors for hernia recurrence after complex AWR. A retrospective review of AWR patients from 2007-2012 was performed. Rates of hernia recurrence were assessed. Univariate analyses and subsequent multivariate logistic regression analysis was used to assess independent predictors of early hernia recurrence. One hundred and thirty-four consecutive cases of AWR were performed over a 5-year period. Hernia recurrence developed in 14 (10.4%) patients. Hernias derived from trauma (OR = 19.76, p = 0.011) and those who experienced postoperative wound infections (OR = 18.81, p = 0.004) were at increased risk for hernia recurrence. In conclusion, increased vigilance must be paid to patients presenting after trauma with massive loss of domain and those who experience postoperative infection, as these cohorts are at added risk for failed reconstruction. PMID:24693869
Wink, Jason D; Wes, Ari M; Fischer, John P; Nelson, Jonas A; Stranksy, Carrie; Kovach, Stephen J
Organ culture in 3-dimensional matrix: in vitro model for evaluating biological compliance of synthetic meshes for abdominal wall repair.
A new in vitro method to evaluate the early critical interactions between synthetic prosthetic materials and growing tissues is reported. The correct spatial organization and proper cell to cell interaction required to mimic the in vivo environment was obtained in a 3-dimensional (3-D) embryo organ culture. The clot formed by plasma and chick-embryo extract provided a natural 3-D extracellular matrix that was able to support the growth and differentiation of intestinal tissue dissected from 12-day-old chick embryos. Different materials used for the repair of abdominal wall defects were taken as standards; all the prosthetic materials were devoid of any evident cytotoxic potential over a 10-day culture period, so they did not interfere with the organogenesis process. A polyglactin mesh (Vicryl) was fully incorporated into the growing tissue, but early signs of its degradation were detectable. The biologically inert materials polyethylene terephthalate (Mersilene) and polypropylene (Marlex, Prolene, and Herniamesh) retained their structural integrity when incubated with cultured tissue at 37 degrees C, and they did not hinder cellular proliferation or fibroblast migration. However, the outgrowth behavior was very different while the connective tissue invaded the interstices of the polyethylene terephthalate mesh; the explants and the migrating cells were repelled by hydrophobic polypropylene meshes. These findings are in agreement with other reported results in in vivo studies. Therefore, this method can be considered as reliable and predictable for the evaluation of biopolymers. PMID:9619439
Dasdia, T; Bazzaco, S; Bottero, L; Buffa, R; Ferrero, S; Campanelli, G; Dolfini, E
Reconstruction of large-size abdominal wall defect using biodegradable poly-p-dioxanone mesh: an experimental canine study
Background Reconstruction of large-size abdominal wall defect (AWDs) is a huge challenge faced in current surgical practice. In this study, we aimed to evaluate the effectiveness and safety of biodegradable poly-p-dioxanone (PDO) mesh for reconstructing large-size AWDs in an experimental canine model. Methods Eighteen experimental canines were randomly and equally divided into three groups, namely, a PDO group, a Marlex group and a control group (n = 6 each). Following the creation of a 6 cm ū 5.5 cm AWD, PDO mesh and Marlex mesh were used to reconstruct the defect in the PDO and Marlex groups, respectively. The defect was closed using relaxation sutures alone in the control group. Animals were killed 24 weeks after surgery, and reconstruction outcomes were evaluated using radiography, histology and biomechanical testing. Results All animals except those in the control group survived the experiment. The PDO group showed no wound dehiscence, herniation or infection, whereas the animals in the Marlex group exhibited marked foreign body reactions. The PDO group had less intraabdominal adhesion than the Marlex group. As shown by radiography, histology and biomechanical testing, PDO mesh exhibited complete degradation and favorable biochemical strength at 24 weeks postsurgery. Conclusions PDO mesh implantation is an effective, safe treatment modality for reconstructing large-size AWDs. PMID:24625138
The combined effects of conduction, natural convection and radiation on heat transfer through a thick wall exposed to the sun
NASA Astrophysics Data System (ADS)
Consideration is given to the problem of heat conduction in a thick wall exposed to a constant radiative flux density on one face with convective and radiative boundary conditions. The equation of heat conduction within the wall with the appropriate boundary conditions taking into account the three most common regimes of convective flow is solved numerically using a second-order implicit finite difference scheme and an alternating direction method. It is found that the effects of longitudinal convection remain constant for wall height/thickness ratios greater than 3, allowing the problem to be reduced one depending on five parameters. Results may be used in the optimization of vertical solar heat collection and storage walls.
Yguel, F.; Peube, J.-L.
The preferential contraction ratios of transversus abdominis on the variations of knee angles during abdominal drawing-in maneuver in wall support standing
The objective of this study was to determine appropriate knee angles for the abdominal drawing-in maneuver (ADIM) through evaluation of changes in contraction ratios of the abdominal muscles and activity of quadriceps muscle in relation to changes in knee angles occurring while the ADIM is performed in the wall support standing (WSS). 20 subjects performed the ADIM at different knee angles (0░, 20░, 40░, 60░) in random order, standing at a point 6 inches away from the wall with the spine maintained in the neutral position. The WSS with knee flexion at 20░ showed significantly higher preferential contraction ratio (PCR) of transversus abdominis (TrA) compared to other positions (0░, 40░, 60░). Therefore, performing the ADIM in the WSS with knee flexion at 20░ appears to be the most appropriate position for TrA PCR. PMID:24877045
Hwang, Young-In; Kim, Jwa-Jun; Park, Du-Jin
Reconstruction of full-thickness chest wall defects using rectus abdominis musculocutaneous flap: A report of fifteen cases
In 15 patients chest walls were excised because of recurrent breast cancer, radiation ulcer, or rib tumor. In most cases the full-thickness defect of the chest wall was about 10 x 10 cm. Reconstruction was performed using only a rectus abdominis musculocutaneous flap. No patient developed circulation problems in the flap or severe flail chest, and we had successful results in all our cases. These results show that the rectus abdominis musculocutaneous flap is quite effective and safe to use in the reconstruction of chest wall defects.
Miyamoto, Y.; Hattori, T.; Niimoto, M.; Toge, T. (Hiroshima Univ. School of Medicine (Japan))
Utilization of a global data grid repository in CAD assessment of carotid wall thickness
NASA Astrophysics Data System (ADS)
A CAD method of calculating wall thickness of carotid vessels addresses the time-consuming issue of using B-mode ultrasound as well as inter- and intra-observer variability in results. Upon selection of a region-of-interest and filtering of a series of ultrasound carotid images, the CAD is able to measure the geometry of the lumen and plaque surfaces using a least-square fitting of the active contours during systole and diastole. To evaluate the approach, ultrasound image sequences from 30 patients were submitted to the procedure. The images were stored on an international data grid repository that consists of three international sites: Image Processing and Informatics (IPI) Laboratory at University of Southern California, USA; InCor (Heart Institute) at Sao Paulo, Brazil, and Hong Kong Polytechnic University, Hong Kong. The three chosen sites are connected with high speed international networks including the Internet2, and the Brazilian National Research and Education Network (RNP2). The Data Grid was used to store, backup, and share the ultrasound images and analysis results, which provided a large-scale and a virtual data system. In order to study the variability between the automatic and manual definition of artery boundaries, the pooled mean and the standard deviation for the difference between measurements of lumen diameter were computed. The coefficient of variation and correlation were also calculated. For the studied population the difference between manual and automatic measurement of the lumen diameter (LD) and intima-media-thickness (IMT) were 0.12 +/-0.10 and 0.09+/- 0.06, respectively.
Gutierrez, Marco A.; Lee, Jasper; Zhou, Zheng; Pilon, Paulo E.; Lage, Silvia G.
Dynamics of cylindrical and spherical relativistic domain walls of finite thickness
The dynamics of cylindrical and spherical relativistic domain walls is investigated with the help of a new method based on the Taylor expansion of the scalar field in a vicinity of the core of the wall. Internal oscillatory modes for the domain walls are found. These modes are nonanalytic in the ``width'' of the domain wall. A rather nontrivial transformation
H. Arodz; A. L. Larsen
Resonant phenomena of circumferential Lamb waves by eight transducer elements located evenly on girth and wall thickness measurements
NASA Astrophysics Data System (ADS)
The purpose of this paper is to present a newly developed method for measuring a wall thickness using the resonance of the circumferential (C-) Lamb wave. In this method, a piezoelectric ring-shaped sensor (PeRS used normally for the torsional guided waves propagating along the axial directions) is used for the transduction of the C-Lamb waves. The PeRS used in the experiments has the eight transducer elements located evenly on the girth for the guided wave generations. Because the transducer elements vibrate circumferential directions, the axial torsional guided waves and the C-Lamb waves are generated simultaneously. The C-Lamb waves are usually spurious signals for the axial guided wave inspections; however, in the method, the resonant phenomena of the C-Lamb waves are utilized for the wall thickness estimations. It was shown that the measurement of the resonant frequency enabled the wall thickness estimation. The experimental verifications of the principle were also shown. The results showed that the experimental estimations of wall thicknesses agreed excellently with the theoretical predictions.
Nishino, Hideo; Morita, Keiichi
Relationship of Periodontal Disease to Carotid Artery Intima-Media Wall Thickness The Atherosclerosis Risk in Communities (ARIC) Study
Periodontitis has been linked to clinical cardiovascular disease but not to subclinical atherosclerosis. The purpose of this study was to determine whether periodontitis is associated with carotid artery intima-media wall thickness (IMT). Cross-sectional data on 6017 persons aged 52 to 75 years were obtained from the Atherosclerosis Risk in Communities Study 1996 to 1998 examination. The dependent variable was carotid
James D. Beck; John R. Elter; Gerardo Heiss; David Couper; Sally M. Mauriello; Steven Offenbacher
Bobbin-Tool Friction-Stir Welding of Thick-Walled Aluminum Alloy Pressure Vessels
It was desired to assemble thick-walled Al alloy 2219 pressure vessels by bobbin-tool friction-stir welding. To develop the welding-process, mechanical-property, and fitness-for-service information to support this effort, extensive friction-stir welding-parameter studies were conducted on 2.5 cm. and 3.8 cm. thick 2219 Al alloy plate. Starting conditions of the plate were the fully-heat-treated (-T62) and in the annealed (-O) conditions. The former condition was chosen with the intent of using the welds in either the 'as welded' condition or after a simple low-temperature aging treatment. Since preliminary stress-analyses showed that stresses in and near the welds would probably exceed the yield-strength of both 'as welded' and welded and aged weld-joints, a post-weld solution-treatment, quenching, and aging treatment was also examined. Once a suitable set of welding and post-weld heat-treatment parameters was established, the project divided into two parts. The first part concentrated on developing the necessary process information to be able to make defect-free friction-stir welds in 3.8 cm. thick Al alloy 2219 in the form of circumferential welds that would join two hemispherical forgings with a 102 cm. inside diameter. This necessitated going to a bobbin-tool welding-technique to simplify the tooling needed to react the large forces generated in friction-stir welding. The bobbin-tool technique was demonstrated on both flat-plates and plates that were bent to the curvature of the actual vessel. An additional issue was termination of the weld, i.e. closing out the hole left at the end of the weld by withdrawal of the friction-stir welding tool. This was accomplished by friction-plug welding a slightly-oversized Al alloy 2219 plug into the termination-hole, followed by machining the plug flush with both the inside and outside surfaces of the vessel. The second part of the project involved demonstrating that the welds were fit for the intended service. This involved determining the room-temperature tensile and elastic-plastic fracture-toughness properties of the bobbin-tool friction-stir welds after a post-weld solution-treatment, quenching, and aging heat-treatment. These mechanical properties were used to conduct fracture-mechanics analyses to determine critical flaw sizes. Phased-array and conventional ultrasonic non-destructive examination was used to demonstrate that no flaws that match or exceed the calculated critical flaw-sizes exist in or near the friction-stir welds.
Dalder, E C; Pastrnak, J W; Engel, J; Forrest, R S; Kokko, E; Ternan, K M; Waldron, D
On dynamics of cylindrical and spherical relativistic domain walls of finite thickness
Dynamics of cylindrical and spherical relativistic domain walls is investigated with the help of a new method based on Taylor expansion of the scalar field in a vicinity of the core of the wall. Internal oscillatory modes for the domain walls are found. These modes are non-analytic in the "width" of the domain wall. Rather non-trivial transformation to a special coordinate system, widely used in investigations of relativistic domain walls, is studied in detail.
H. Arodz; A. L. Larsen
Dynamics of cylindrical and spherical relativistic domain walls of finite thickness
NASA Astrophysics Data System (ADS)
The dynamics of cylindrical and spherical relativistic domain walls is investigated with the help of a new method based on the Taylor expansion of the scalar field in a vicinity of the core of the wall. Internal oscillatory modes for the domain walls are found. These modes are nonanalytic in the ``width'' of the domain wall. A rather nontrivial transformation to a special coordinate system, widely used in investigations of relativistic domain walls, is studied in detail.
Arod?, H.; Larsen, A. L.
On dynamics of cylindrical and spherical relativistic domain walls of finite thickness
Dynamics of cylindrical and spherical relativistic domain walls is investigated with the help of a new method based on Taylor expansion of the scalar field in a vicinity of the core of the wall. Internal oscillatory modes for the domain walls are found. These modes are non-analytic in the "width" of the domain wall. Rather non-trivial transformation to a special coordinate system, widely used in investigations of relativistic domain walls, is studied in detail.
Arodz, H
Stability of a microvessel subject to structural adaptation of diameter and wall thickness.
Vascular adaptation--or structural changes of microvessels in response to physical and metabolic stresses--can influence physiological processes like angiogenesis and hypertension. To better understand the influence of these stresses on adaptation, Pries et al. (1998, 2001a,b, 2005) have developed a computational model for microvascular adaptation. Here, we reformulate this model in a way that is conducive to a dynamical systems analysis. Using th ese analytic methods, we determine the equilibrium geometries of a single vessel under different conditions and classify its type of stability. We demonstrate that our closed-form solution for vessel geometry exhibits the same regions of stability as the numerical predictions of Pries et al. (2005, Remodeling of blood vessels: responses of diameter and wall thickness to hemodynamic and metabolic stimuli. Hypertension, 46, 725-731). Our analytic approach allows us to predict the existence of limit-cycle oscillations and to extend the model to consider a fixed pressure across the vessel in addition to a fixed flow. Under these fixed pressure conditions, we show that the vessel stability is affected and that the multiple equilibria can exist. PMID:20870949
Shafer, Ilari; Nancollas, Rachel; Boes, Morgan; Sieminski, Alisha L; Geddes, John B
Tensile, Compression and Fracture Properties of Thick-Walled Ductile Cast Iron Components
NASA Astrophysics Data System (ADS)
The article presents the outcome of a comprehensive program of tensile, compression and fracture toughness experiments, addressing thick-walled ductile cast iron inserts used for the production of three nuclear waste canisters. The resulting data are required as input to the assessment of the failure probability of the canisters. Moreover, these data are useful for the improvement of the casting technique as such. Although the same material specification is always used, material properties are found to show significant variation. Considerable attention is paid to linking the scatter in tensile properties to fractographic and microstructural observations. The main finding is that low ductility tensile test results can be primarily connected to the presence of specific casting defects, from which oxide films have the most detrimental effect. Another important observation is that compression experiments do not result in low ductility failure. During fracture testing, stable ductile crack propagation is observed. Basic fracture analysis of a tensile test is performed in order to better understand the effect of defect size, stress-strain behavior and fracture toughness on the ductility measured through tensile testing. Two opposing specimen size effects are observed.
Minnebo, P.; Nilsson, K.-F.; Blagoeva, D.
Evaluation of a canine small intestinal submucosal xenograft and polypropylene mesh as bioscaffolds in an abdominal full-thickness resection model of growing rats.
We evaluated the biological scaffold properties of canine small intestinal submucosa (SIS) compared to a those of polypropylene mesh in growing rats with full-thickness abdominal defects. SIS is used to repair musculoskeletal tissue while promoting cell migration and supporting tissue regeneration. Polypropylene mesh is a non-resorbable synthetic material that can endure mechanical tension. Canine SIS was obtained from donor German shepherds, and its porous collagen fiber structure was identified using scanning electron microscopy (SEM). A 2.50-cm(2) section of canine SIS (SIS group) or mesh (mesh group) was implanted in Sprague-Dawley rats. At 1, 2, 4, 12, and 24 weeks after surgery, the implants were histopathologically examined and tensile load was tested. One month after surgery, CD68+ macrophage numbers in the SIS group were increased, but the number of CD8+ T cells in this group declined more rapidly than that in rats treated with the mesh. In the SIS group, few adhesions and well-developed autologous abdominal muscle infiltration into the SIS collagen fibers were observed. No significant differences in the tensile load test results were found between the SIS and mesh groups at 24 weeks. Canine SIS may therefore be a suitable replacement for artificial biological scaffolds in small animals. PMID:23628657
Lee, A-Jin; Lee, Sung-Ho; Chung, Wook-Hun; Kim, Dae-Hyun; Chung, Dai-Jung; Do, Sun Hee; Kim, Hwi-Yool
Evaluation of a canine small intestinal submucosal xenograft and polypropylene mesh as bioscaffolds in an abdominal full-thickness resection model of growing rats
We evaluated the biological scaffold properties of canine small intestinal submucosa (SIS) compared to a those of polypropylene mesh in growing rats with full-thickness abdominal defects. SIS is used to repair musculoskeletal tissue while promoting cell migration and supporting tissue regeneration. Polypropylene mesh is a non-resorbable synthetic material that can endure mechanical tension. Canine SIS was obtained from donor German shepherds, and its porous collagen fiber structure was identified using scanning electron microscopy (SEM). A 2.50-cm2 section of canine SIS (SIS group) or mesh (mesh group) was implanted in Sprague-Dawley rats. At 1, 2, 4, 12, and 24 weeks after surgery, the implants were histopathologically examined and tensile load was tested. One month after surgery, CD68+ macrophage numbers in the SIS group were increased, but the number of CD8+ T cells in this group declined more rapidly than that in rats treated with the mesh. In the SIS group, few adhesions and well-developed autologous abdominal muscle infiltration into the SIS collagen fibers were observed. No significant differences in the tensile load test results were found between the SIS and mesh groups at 24 weeks. Canine SIS may therefore be a suitable replacement for artificial biological scaffolds in small animals. PMID:23628657
Lee, A-Jin; Lee, Sung-Ho; Chung, Wook-Hun; Kim, Dae-Hyun; Chung, Dai-Jung; Do, Sun Hee
Evaluation of side effects of radiofrequency capacitive hyperthermia with magnetite on the blood vessel walls of tumor metastatic lesion surrounding the abdominal large vessels: an agar phantom study
Background Magnetite used in an 8-MHz radiofrequency (RF) capacitive heating device can increase the temperature of a specific site up to 45░C. When treating a metastatic lesion around large abdominal vessels via hyperthermia with magnetite, heating-induced adverse effects on these vessels need to be considered. Therefore, this study examined hyperthermia-induced damage to blood vessel walls in vitro. Methods A large agar phantom with a circulatory system consisting of a swine artery and vein connected to a peristaltic pump was prepared. The blood vessels were placed on the magnetite-containing agar piece. Heating was continued for 30Āmin at 45░C. After heating, a histological study for injury to the blood vessels was performed. Results The inner membrane temperature did not reach 45░C due to the cooling effect of the blood flow. In the heated vessels, vascular wall collagen degenerated and smooth muscle cells were narrowed; however, no serious changes were noted in the vascular endothelial cells or vascular wall elastic fibers. The heated vessel wall was not severely damaged; this was attributed to cooling by the blood flow. Conclusions Our findings indicate that RF capacitive heating therapy with magnetite may be used for metastatic lesions without injuring the surrounding large abdominal vessels. PMID:25114787
Please cite this article in press as: C. Zohios, et al., Geometrical methods for level set based abdominal aortic aneurysm thrombus and outer wall 2D image segmentation, Comput. Methods Programs Biomed. (2011), doi:10.1016/j.cmpb.2011.06.009
abdominal aortic aneurysm thrombus and outer wall 2D image segmentation, Comput. Methods Programs Biomed.intl.elsevierhealth.com/journals/cmpb Geometrical methods for level set based abdominal aortic aneurysm thrombus and outer wall 2D image form 9 December 2010 Accepted 28 June 2011 Keywords: Abdominal aortic aneurysm Level Set Methods
Papaharilaou, Yannis
... cut. These will be removed later. A firm elastic dressing (bandage) will be placed over your abdomen. ... to reduce pressure on your abdomen. Wearing an elastic support similar to a girdle for 2 to ...
Airway wall thickness associated with forced expiratory volume in 1 second decline and development of airflow limitation.
Airway wall thickness and emphysema contribute to airflow limitation. We examined their association with lung function decline and development of airflow limitation in 2021 male smokers with and without airflow limitation. Airway wall thickness and emphysema were quantified on chest computed tomography and expressed as the square root of wall area of a 10-mm lumen perimeter (Pi10) and the 15th percentile method (Perc15), respectively. Baseline and follow-up (median (interquartile range) 3 (2.9-3.1)?years) spirometry was available. Pi10 and Perc15 correlated with baseline forced expiratory volume in 1?s (FEV1) (r=?-0.49 and 0.11, respectively (p<0.001)). Multiple linear regression showed that Pi10 and Perc15 at baseline were associated with a lower FEV1 after follow-up (p<0.05). For each sd increase in Pi10 and decrease in Perc15 the FEV1 decreased by 20?mL and 30.2?mL, respectively. The odds ratio for developing airflow limitation after 3?years was 2.45 for a 1-mm higher Pi10 and 1.46 for a 10-HU lower Perc15 (p<0.001). A greater degree of airway wall thickness and emphysema was associated with a higher FEV1 decline and development of airflow limitation after 3?years of follow-up. PMID:25614166
Mohamed Hoesein, Firdaus A A; de Jong, Pim A; Lammers, Jan-Willem J; Mali, Willem P T M; Schmidt, Michael; de Koning, Harry J; van der Aalst, Carlijn; Oudkerk, Matthijs; Vliegenthart, Rozemarijn; Groen, Harry J M; van Ginneken, Bram; van Rikxoort, Eva M; Zanen, Pieter
Necrotizing fasciitis: literature review of contemporary strategies for diagnosing and management with three case reports: torso, abdominal wall, upper and lower limbs
Necrotizing fasciitis (NF) is an uncommon soft tissue infection, usually caused by toxin-producing virulent bacteria. It is characterized by widespread fascial necrosis primarily caused by Streptococcus hemolyticus. Shortly after the onset of the disease, patients become colonized with their own aerobic and anaerobic microflora from the gastrointestinal and/or urogenital tracts. Early diagnosis with aggressive multidisciplinary treatment is mandatory. We describe three clinical cases with NF. The first is a 69 years old man with diabetes mellitus type II, who presented with NF on the posterior chest wall, shoulder and arm. He was admitted to the intensive care unit (ICU) with a clinical picture of severe sepsis. Outpatient treatment and early surgical debridement of the affected zones (inside 3 hours after admittance) and critical care therapy were performed. The second case is of a 63 years old paraplegic man with diabetes mellitus type I. Pressure sores and perineal abscesses progressed to Fournier's gangrene of the perineum and scrotum. He had NF of the anterior abdominal wall and the right thigh. Outpatient treatment and early surgical debridement of the affected zones (inside 6 hour after admittance) and critical care therapy were performed. The third patient was a 56 year old man who had NF of the anterior abdominal wall, flank and retroperitoneal space. He had an operation of the direct inguinal hernia, which was complicated with a bowel perforation and secondary peritonitis. After establishing the diagnosis of NF of the abdominal wall and retroperitoneal space (RS), he was transferred to the ICU. There he first received intensive care therapy, after which emergency surgical debridement of the abdominal wall, left colectomy, and extensive debridement of the RS were done (72 hours after operation of inquinal hernia). On average, 4 serial debridements were performed in each patient. The median of serial debridement in all three cases was four times. Other intensive care therapy with a combination of antibiotics and adjuvant hyperbaric oxygen therapy (HBOT) was applied during the treatment. After stabilization of soft tissue wounds and the formation of fresh granulation tissue, soft tissue defect were reconstructed using simple to complex reconstructive methods. PMID:22196774
Necrotizing fasciitis: literature review of contemporary strategies for diagnosing and management with three case reports: torso, abdominal wall, upper and lower limbs.
Necrotizing fasciitis (NF) is an uncommon soft tissue infection, usually caused by toxin-producing virulent bacteria. It is characterized by widespread fascial necrosis primarily caused by Streptococcus hemolyticus. Shortly after the onset of the disease, patients become colonized with their own aerobic and anaerobic microflora from the gastrointestinal and/or urogenital tracts. Early diagnosis with aggressive multidisciplinary treatment is mandatory. We describe three clinical cases with NF. The first is a 69 years old man with diabetes mellitus type II, who presented with NF on the posterior chest wall, shoulder and arm. He was admitted to the intensive care unit (ICU) with a clinical picture of severe sepsis. Outpatient treatment and early surgical debridement of the affected zones (inside 3 hours after admittance) and critical care therapy were performed. The second case is of a 63 years old paraplegic man with diabetes mellitus type I. Pressure sores and perineal abscesses progressed to Fournier's gangrene of the perineum and scrotum. He had NF of the anterior abdominal wall and the right thigh. Outpatient treatment and early surgical debridement of the affected zones (inside 6 hour after admittance) and critical care therapy were performed. The third patient was a 56 year old man who had NF of the anterior abdominal wall, flank and retroperitoneal space. He had an operation of the direct inguinal hernia, which was complicated with a bowel perforation and secondary peritonitis. After establishing the diagnosis of NF of the abdominal wall and retroperitoneal space (RS), he was transferred to the ICU. There he first received intensive care therapy, after which emergency surgical debridement of the abdominal wall, left colectomy, and extensive debridement of the RS were done (72 hours after operation of inquinal hernia). On average, 4 serial debridements were performed in each patient. The median of serial debridement in all three cases was four times. Other intensive care therapy with a combination of antibiotics and adjuvant hyperbaric oxygen therapy (HBOT) was applied during the treatment. After stabilization of soft tissue wounds and the formation of fresh granulation tissue, soft tissue defect were reconstructed using simple to complex reconstructive methods. PMID:22196774
Roje, Zdravko; Roje, Zeljka; Mati?, Dario; Librenjak, Davor; Dokuzovi?, Stjepan; Varvodi?, Josip
Charged magnetic domain walls as observed in nanostructured thin films: dependence on both film thickness and anisotropy
NASA Astrophysics Data System (ADS)
The magnetic domain configurations of soft magnetic, nanostructured, pulsed laser-deposited Co films were investigated. Their dependence on both the thickness t (20 nm ? t ? 200 nm) and the anisotropy was studied. Charged zigzag walls, with a characteristic saw-tooth vertex angle ?, were observed. ? changed with t from ? ? 17░ to ?25░, presenting an intermediate sharp maximum that has not been described before. The reduced length of the zigzag walls also exhibited a peak at t ? 70 nm. The relationship between the total reduced length and the density energy of the magnetic wall allowed us to establish a change from a Nķel-type to a Bloch-type core of the zigzag walls at this thickness, t ? 70 nm. We also accounted for the magnetic energy arising from the surface roughness of the thinner films after imaging the film surface morphologies. Moreover, this distinctive behaviour of the zigzag walls of these low-anisotropy films was compared to that of high-anisotropy films.
Favieres, C.; Vergara, J.; Madurga, V.
Sarcocystis sinensis is the most prevalent thick-walled Sarcocystis species in beef on sale for consumers in Germany.
Bovines are intermediate hosts of Sarcocystis cruzi, Sarcocystis hirsuta, and Sarcocystis hominis, which use canids, felids, or primates as definitive hosts, respectively. Cattle represent also intermediate hosts of Sarcocystis sinensis, but the definitive hosts of this parasite are not yet known. Sarcocystosis in cattle is frequently asymptomatic. The infection is characterized by the presence of thin-walled (S. cruzi) or thick-walled muscle cysts or sarcocysts (S. hominis, S. sinensis, and S. hirsuta). Recent reports suggest high prevalence of the zoonotic S. hominis in beef in Europe. We therefore aimed at differentiating Sarcocystis spp. in beef offered to consumers in Germany using molecular and microscopical methods, focusing on those species producing thick-walled sarcocysts. A total of 257 beef samples were obtained from different butcheries and supermarkets in Germany and processed by conventional and multiplex real-time PCR. In addition, 130 of these samples were processed by light microscopy and in 24.6% thick-walled cysts were detected. Transmission electron microscopical analysis of six of these samples revealed an ultrastructural cyst wall pattern compatible with S. sinensis in five samples and with S. hominis in one sample. PCR-amplified 18S ribosomal DNA (rDNA) fragments of 28 individual thick-walled cysts were sequenced, and sequence identities of ?98% with S. sinensis (n?=?22), S. hominis (n?=?5) and S. hirsuta (n?=?1) were observed. Moreover, nine Sarcocystis sp. 18S rDNA full length gene sequences were obtained, five of S. sinensis, three of S. hominis, and one of S. hirsuta. Out of all samples (n?=?257), 174 (67.7%) tested positive by conventional PCR and 179 (69.6%) by multiplex real-time PCR for Sarcocystis spp. Regarding individual species, 134 (52%), 95 (37%), 17 (6.6%), and 16 (6.2%) were positive for S. cruzi, S. sinensis, S. hirsuta, and S. hominis, respectively. In conclusion, S. sinensis is the most prevalent thick-walled Sarcocystis species in beef offered for consumption in Germany. Further studies are needed to identify the final host of S. sinensis as well as the potential role of this protozoan as a differential diagnosis to the zoonotic species S. hominis. PMID:24700022
Morķ, G; Pantchev, A; Skuballa, J; Langenmayer, M C; Maksimov, P; Conraths, F J; Venturini, M C; Schares, G
The mechanism of instability and localized reaction in the explosively driven collapse of thick walled Ni-Al laminate cylinders
NASA Astrophysics Data System (ADS)
Thick-walled cylinders constructed from alternating concentric layers of Ni and Al foils were explosively collapsed. The prevalent mode of the high strain, high strain rate plastic deformation was the cooperative buckling of the foils originating in the interior layers. This phenomenon was reproduced in numerical simulations. Its mechanism is qualitatively different than that of shear localization seen in all previously investigated homogeneous solid and granular materials and from the independent buckling of single thin-walled cylinders. Localized chemical reactions were observed in the apex areas of the Ni foils, consistent with the localization of temperature due to high strain plastic deformation.
Chiu, P. H.; Olney, K. L.; Higgins, A.; Serge, M.; Benson, D. J.; Nesterenko, V. F.
Method and Apparatus to Produce and Maintain a thick, flowing, Liquid Lithium first wall for Toroidal Magnetic Confinement DT Fusion Reactors
A system for forming a thick flowing liquid metal, in this case lithium, layer on the inside wall of a toroid containing the plasma of a deuterium-tritium fission reactor. The presence of the liquid metal layer or first wall serves to prevent neutron damage to the walls of the toroid. A poloidal current in the liquid metal layer is oriented
Woolley; Robert D
Method and apparatus to produce and maintain a thick, flowing, liquid lithium first wall for toroidal magnetic confinement DT fusion reactors
A system for forming a thick flowing liquid metal, in this case lithium, layer on the inside wall of a toroid containing the plasma of a deuterium-tritium fusion reactor. The presence of the liquid metal layer or first wall serves to prevent neutron damage to the walls of the toroid. A poloidal current in the liquid metal layer is oriented
Woolley; Robert D
Recommendations for protecting against failure by brittle fracture: Category II and III ferritic steel shipping containers with wall thickness greater than four inches
This report provides criteria for selecting ferritic steels that would prevent brittle fracture in Category II and III shipping containers with wall thickness greater than 4 inches. These methods are extensions of those previously used for Category II and III containers less than 4 inches thick and Category I containers more than 4 inches thick.
Schwartz, M.W.; Fischer, L.E. [Lawrence Livermore National Lab., CA (United States)
Full-thickness chest wall resection for recurrent breast carcinoma: an institutional review and meta-analysis.
Locoregional recurrence of breast cancer can occur in up to 30 per cent of patients and has often been considered to indicate a poor prognosis. We reviewed our experience with full-thickness chest wall resection for recurrent breast cancer and conducted a meta-analysis of the English literature to determine patient characteristics and outcomes. Twenty-two women with isolated chest wall recurrence of breast cancer were treated between 1970 and 2000 at our institution. We reviewed their preoperative demographics, operative management and outcome, and combined our results with seven other English language studies. A majority of women (90%) underwent a mastectomy as initial management of their breast cancer. Only 18 per cent of patients had metastatic disease at the time of chest wall resection, and 71 per cent of patients had an R0 resection. The 5-year disease-free survival at City of Hope National Medical Center (COH) was 67 per cent and was 45 per cent for the entire group of 400 patients. The 5-year overall survival was 71 per cent for the COH group and 45 per cent for the entire group. Several studies reported prognostic factors, the most common being a better prognosis in patients with a disease-free interval greater than 24 months. Full-thickness chest wall resection for patients with isolated local recurrence of breast cancer can provide long-term palliation and even cure in some patients. PMID:16468503
Pameijer, Colette R J; Smith, David; McCahill, Laurence E; Bimston, David N; Wagman, Lawrence D; Ellenhorn, Joshua D I
Riser Difference Evaluation from Ultrasonic Wall Thickness Inspection of Thirteen Double-Shell Tanks
PNNL has performed an analysis of ultrasonic thickness measurements taken on Hanford's double-shell tanks (DSTs) approximately eight years apart. The analysis was performed to determine whether significant differences exist between ultrasonic thickness measurements made in two opposite risers in Hanford DSTs that have been examined twice.
Weier, Dennis R.; Pardini, Allan F.
Preoperative treatment with doxycycline reduces aortic wall expression and activation of matrix metalloproteinases in patients with abdominal aortic aneurysms
Purpose: Matrix metalloproteinases (MMPs) are considered to play a central role in the pathogenesis of abdominal aortic aneurysms (AAAs). Doxycycline (Dox) has direct MMP-inhibiting properties in vitro, and it effectively suppresses the development of elastase-induced AAAs in rodents. The purpose of this study was to determine if treatment with Dox suppresses AMPS within human aneurysm tissue and to elucidate the
John A Curci; Dongli Mao; Diane G Bohner; Brent T Allen; Brian G Rubin; Jeffrey M Reilly; Gregorio A Sicard; Robert W Thompson
The hypertrophy of the lateral abdominal wall and quadratus lumborum is sport-specific: an MRI segmental study in professional tennis and soccer players.
The aim was to determine the volume and degree of asymmetry of quadratus lumborum (QL), obliques, and transversus abdominis; the last two considered conjointly (OT), in tennis and soccer players. The volume of QL and OT was determined using magnetic resonance imaging in professional tennis and soccer players, and in non-active controls (n = 8, 14, and 6, respectively). In tennis players the hypertrophy of OT was limited to proximal segments (cephalic segments), while in soccer players it was similar along longitudinal axis. In tennis players the hypertrophy was asymmetric (18% greater volume in the non-dominant than in the dominant OT, p = 0.001), while in soccer players and controls both sides had similar volumes (p > 0.05). In controls, the non-dominant QL was 15% greater than that of the dominant (p = 0.049). Tennis and soccer players had similar volumes in both sides of QL. Tennis alters the dominant-to-non-dominant balance in the muscle volume of the lateral abdominal wall. In tennis the hypertrophy is limited to proximal segments and is greater in the non-dominant side. Soccer, however, is associated to a symmetric hypertrophy of the lateral abdominal wall. Tennis and soccer elicit an asymmetric hypertrophy of QL. PMID:23724609
Sanchis-Moysi, Joaquin; Idoate, Fernando; Izquierdo, Mikel; Calbet, Jose A; Dorado, Cecilia
The gender-specific chest wall thickness prediction equations for routine measurements of 239Pu and 241Am within the lungs using HPGe detectors.
The current chest wall thickness prediction equation is not applicable to use in routine lung counting measurements for detection of low energy photons (17--60 keV) within the lungs of male and female subjects. The current chest wall thickness prediction equation was derived for the NaI-CsI "phoswich" detection system, which is not the routine detection system in use; the subject position was supine, which is not the routine position; the equation did not account for the intercostal tissue thicknesses of muscle and adipose which significantly attenuate low energy photons (17--60keV); it was derived from male subjects only and is used to predict the chest wall thickness of female subjects for whom it is not applicable. The current chest wall thickness prediction equation yields unacceptable percent errors in the HPGe detection efficiency calibration for 239Pu and 241Am (17- and 59.5-keV photons, respectively) relative to the gender-specific HPGe chest wall thickness prediction equations of this paper (+284% to --73% for 239Pu; (+)42% to --39% for 241Am). As a result, use of the current chest wall thickness prediction equation yields unacceptable percent errors (proportional in magnitude to the percent errors in the detection efficiency calibration) in the calculation of the minimum detectable activity (Bq) or in an initial assessment of a radioactive contamination exposure detected by a routine lung count measurement. PMID:8609026
Vickers, L R
Stress-intensity factors for a thick-walled cylinder containing an annular imbedded or external or internal surface crack
NASA Technical Reports Server (NTRS)
The elastostatic axisymmetric problem for a long thick-walled cylinder containing a ring-shaped internal or edge crack is considered. Using the standard transform technique the problem is formulated in terms of an integral equation which has a simple Cauchy kernel for the internal crack and a generalized Cauchy kernel for the edge crack as the dominant part. As examples the uniform axial load and the steady-state thermal stress problems have been solved and the related stress intensity factors have been calculated. Among other findings the results show that in the cylinder under uniform axial stress containing an internal crack the stress intensity factor at the inner tip is always greater than that at the outer tip for equal net ligament thicknesses and in the cylinder with an edge crack which is under a state of thermal stress the stress intensity factor is a decreasing function of the crack depth, tending to zero as the crack depth approaches the wall thickness.
Erdol, R.; Erdogan, F.
Ureteral wall thickness at the impacted ureteral stone site: a critical predictor for success rates after SWL.
The aim of the study was to determine the possible predictive value of certain patient- and stone-related factors on the stone-free rates and auxiliary procedures after extracorporeal shock wave lithotripsy in patients with impacted proximal ureteral calculi. A total of 111 patients (86 male, 25 females M/F: 3.44/1) with impacted proximal ureteral stones treated with shock wave lithotripsy were evaluated. Cases were retrieved from a departmental shock wave lithotripsy database. Variables analyzed included BMI of the case, diameter of proximal ureter and renal pelvis, stone size and Hounsfield unit, ureteral wall thickness at the impacted stone site. Stone-free status on follow-up imaging at 3 months was considered a successful outcome. All patients had a single impacted proximal ureteral stone. While the mean age of the cases was 46 ▒ 13 years (range 26-79 years), mean stone size was 8.95 mm (5.3-15.1 mm). Following shock wave lithotripsy although 87 patients (78.4%) were completely stone-free at 3-month follow-up visit, 24 (21.6%) cases had residual fragments requiring further repeat procedures. Prediction of the final outcome of SWL in patients with impacted proximal ureteral stones is a challenging issue and our data did clearly indicate a highly significant relationship between ureteral wall thickness and the success rates of shock wave lithotripsy particularly in cases requiring additional procedures. Of all the evaluated stone- and patient-related factors, only ureteral wall thickness at the impacted stone site independently predicted shock wave lithotripsy success. PMID:25417717
Sarica, Kemal; Kafkasli, Alper; Yazici, ųzg³r; Ūetinel, Ali Cihangir; Demirkol, Mehmet Kutlu; Tuncer, Murat; ?ahin, Cahit; Eryildirim, Bilal
Home ╗ Abdominal Migraine Abdominal Migraine Submitted by Admin on Wed, 2007-10-24 12:10 Abdominal migraine is one of the variants of migraine headache. This variant most typically occurs in children, ...
Ventricular wall thickness and volume during hemodynamic collapse produced by AC leakage current
Medical equipment can unintentionally allow the flow of power line current through the patient causing complete hemodynamic collapse without fibrillation. This study tests the hypothesis that static wall thickening accompanies AC induced collapse via an isovolumic state. In 3 dogs, we delivered AC current stimulation ranging from 10-160 Hz and 10-1000 ?A to the right ventricle. A steerable, quadripolar catheter
B. K. Hoffmeister; B. S. Sheals; A. L. de Jongh; R. A. Malkin
Millimeter-Thick Single-Walled Carbon Nanotube Forests: Hidden Role of Catalyst Support
the realizations of the vertically-aligned single-walled carbon nanotube (VA-SWNT) forests1) by alcohol chemical vapor deposition (ACCVD),2) many groups achieved this morphology of nanotubes by several tricks in CVD as for the CVD condition (i.e., 0 to 0.03 kPa). During this heat treatment, Fe formed into a nanoparticle
Maruyama, Shigeo
concrete. The functional unit is first defined per square such that the wall may provide the function or less scattered results in relation with value judgments, assumptions, boundary conditions, scenarios┬▓.K/W. The results then showed that the production phase of raw materials is mainly responsible for the environmental
Paris-Sud XI, Universit├® de
Development of automated welding process for field fabrication of thick walled pressure vessels. Final report
The results review procedure development and qualification for narrow groove gas tungsten arc welding of SA 387 Grade 22 Class 2 steel (2 1\\/4% Cr-1% Mo) to 4 inch thickness. Welding was conducted in the horizontal (2G) and vertical (3G) position.
Development of automated welding process for field fabrication of thick-walled pressure vessels
The following tasks are reported on: review of welding processes, adaptation of the GTAW-HW narrow-groove process to vertical and horizontal welds, 8-inch thick field demonstration/qualification welds, and welding procedure handbook. Procedure qualification records (TQ 339) are given for the gas tungsten arc-hot wire welding of 2 1/4 Cr - 1 Mo steel. (DLC)
Schneider, U.A.
Development of automated welding process for field fabrication of thick walled pressure vessels. Final report
The results review procedure development and qualification for narrow groove gas tungsten arc welding of SA 387 Grade 22 Class 2 steel (2 1/4% Cr-1% Mo) to 4 inch thickness. Welding was conducted in the horizontal (2G) and vertical (3G) position.
Stol, I.
Austenitic stainless steel is widely used in the nuclear industry as structural material because of the creep strength, corrosion resistance and very good high temperature fracture toughness. In the present experimental work, conventional radiography, pulse echo (manual and automated) and TOFD was used to evaluate austenitic stainless steel weld pads of 25 mm thick with defects such as lack of
R. Subbaratnam; B. Venkatraman; Baldev Raj
Axisymmetric Tandem Mirror Magnetic Fusion Energy Power Plant with Thick Liquid-Walls
A fusion power plant is described that utilizes a new version of the tandem mirror device including spinning liquid walls. The magnetic configuration is evaluated with an axisymmetric equilibrium code predicting an average beta of 60%. The geometry allows a flowing molten salt, (flibe-Li{sub 2}BeF{sub 4}), which protects the walls and structures from damage arising from neutrons and plasma particles. The free surface between the liquid and the burning plasma is heated by bremsstrahlung radiation, line radiation, and by neutrons. The temperature of the free surface of the liquid is calculated, and then the evaporation rate is estimated from vapor-pressure data. The allowed impurity concentration in the burning plasma is taken as 1% fluorine, which gives a 17% reduction in the fusion power owing to D/T fuel dilution, with F line-radiation causing minor power degradation. The end leakage power density of 0.6 MW/m{sup 2} is readily handled by liquid jets. The tritium breeding is adequate with natural lithium. A number of problem areas are identified that need further study to make the design more self-consistent and workable; however, the simple geometry and the use of liquid walls promise the cost of power competitive with that from fission and coal.
Moir, R W; Rognlien, T D
Collapse Pressure Analysis of Transversely Isotropic Thick-Walled Cylinder Using Lebesgue Strain Measure and Transition Theory
The objective of this paper is to provide guidance for the design of the thick-walled cylinder made up of transversely isotropic material so that collapse of cylinder due to influence of internal and external pressure can be avoided. The concept of transition theory based on Lebesgue strain measure has been used to simplify the constitutive equations. Results have been analyzed theoretically and discussed numerically. From this analysis, it has been concluded that, under the influence of internal and external pressure, circular cylinder made up of transversely isotropic material (beryl) is on the safer side of the design as compared to the cylinders made up of isotropic material (steel). This is because of the reason that percentage increase in effective pressure required for initial yielding to become fully plastic is high for beryl as compared to steel which leads to the idea of ōstress savingö that reduces the possibility of collapse of thick-walled cylinder due to internal and external pressure. PMID:24523632
Aggarwal, A. K.; Sharma, Richa; Sharma, Sanjeev
FRAM isotopic analysis of uranium in thick-walled containers using high energy gamma rays and planar HPGe detectors.
We describe the use of the Los Alamos FRAM isotopic analysis software to make the first reported measurements on thick-walled UF{sub 6} cylinders using small planar HPGe detectors of the type in common use at the IAEA. Heretofore, planar detector isotopic analysis measurements on uranium have used the 100-keV region and can be defeated by 10 mm of steel absorber. The analysis of planar detector measurements through 13-16 mm of steel shows that FRAM can successfully carry out these measurements and analysis in the 120-1024 keV energy range, a range previously thought to be the sole province of more efficient coaxial detectors. This paper describes the measurement conditions and results and also compares the results to other FRAM measurements with coaxial HPGe detectors. The technique of gamma-ray isotopic analysis of arbitrary samples is desirable for measuring the isotopic composition of uranium in UF{sub 6} cylinders because it does not require calibration with standards or knowledge of the cylinder wall thickness. The International Atomic Energy Agency (IAEA) uses the MGAU (Multi Group Analysis Uranium) uranium isotopic analysis software with planar high purity germanium (HPGe) detectors to measure the isotopic composition of uranium. Measurements on UF{sub 6} cylinders with 13-16-mm thick steel walls are usually unsuccessful because of the strong absorption of the 89-100 keV gamma rays and x-rays that MGAU requires for the measurement. This paper describes the use of the Los Alamos FRAM isotopic analysis software to make these measurements on UF{sub 6} cylinders. Uranium measurements with FRAM typically cover the energy range from 120-1001 keV and can easily be made through the walls of UF{sub 6} cylinders. While these measurements are usually performed with efficient coaxial HPGe detectors, this paper reports the first successful measurements using small planar HPGe detectors of the type in common use at the IAEA.
Sampson, Thomas E.; Hypes, P. A. (Philip A.); Vo, Duc T.
Stresses in thick-walled FGM cylinders with exponentially-varying properties
Power series solutions for stresses and displacements in functionally-graded cylindrical vessels subjected to internal pressure alone are obtained using the infinitesimal theory of elasticity. The material is assumed to be isotropic with constant PoissonÆs ratio and exponentially-varying elastic modulus through the thickness. Stress distributions depending on an inhomogeneity constant are calculated and presented in the form of graphs. The inhomogeneity
Naki Tutuncu
Viscoelastic fluid flow in a 2D channel bounded above by a deformable finite thickness elastic wall
The steady flow of three viscoelastic fluids (Oldroyd-B, FENE-P, and Owens model for blood) in a two-dimensional channel, partly bound by a deformable, finite thickness neo-Hookean solid, is computed. The limiting Weissenberg number beyond which computations fail to converge is found to increase with increasing dimensionless solid elasticity parameter {\\Gamma}, following the trend Owens > FENE- P > Oldroyd-B. The highly shear thinning nature of Owens model leads to the elastic solid always collapsing into the channel, for the wide range of values of {\\Gamma} considered here. In the case of the FENE-P and Oldroyd-B models, however, the fluid-solid interface can be either within the channel, or bulge outwards, depending on the value of {\\Gamma}. This behaviour differs considerably from predictions of earlier models that treat the deformable solid as a zero-thickness membrane, in which case the membrane always lies within the channel. The capacity of the solid wall to support both pressure and shear stress, in contrast to the zero-thickness membrane that only responds to pressure, is responsible for the observed difference. Compar- ison of the stress and velocity fields in the channel for the three viscoelastic fluids, with the predictions for a Newtonian fluid, reveals that shear thinning rather than elasticity is the key source of the observed differences in behaviour.
Debadi Chakraborty; J. Ravi Prakash
Development of automated welding process for field fabrication of thick-walled pressure vessels. Final report
The research discussed herein was conducted for the Tampa Plant as part of the Department of Energy Contract EF-77-C-01-2771. The report comprises the Final Report of the Research and Development Center participation in this contract. The results review procedure development and qualification for narrow groove gas tungsten arc welding of SA 387 Grade 22 Class 2 steel (2 1/4% Cr-1% Mo) to 4 inch thickness. Welding was conducted in the horizontal (2G) and vertical (3G) position.
Stol, I.
Fluid wall shear stress measurements in a model of the human abdominal aorta: oscillatory behavior and relationship to atherosclerosis
Clinically significant atherosclerosis in the human aorta is most common in the infrarenal segment. This study was initiated to test the hypothesis that flowfield properties are closely related to the localization of plaques in this segment of the arteial system. Wall shear stress was calculated from magnetic resonance velocity measurements of pulsatile flow in an anatomically accurate model of the
James E. Moore Jr; Christopher K. Zarins; David N. Ku
The impact of transcatheter aortic valve implantation on left ventricular performance and wall thickness ¢ single-centre experience
Introduction Transcatheter aortic valve implantation (TAVI) is a treatment alternative for the elderly population with severe symptomatic aortic stenosis (AS) at high risk for surgical aortic valve replacement (SAVR). Aim To assess the impact of TAVI on echocardiographic parameters of left ventricular (LV) performance and wall thickness in patients subjected to the procedure in a single-centre between 2009 and 2013. Material and methods The initial group consisted of 170 consecutive patients with severe AS unsuitable for SAVR. Logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) was 21.73 ▒12.42% and mean age was 79.9 ▒7.5 years. Results The TAVI was performed in 167 (98.2%) patients. Mean aortic gradient decreased significantly more rapidly after the procedure (from 58.6 ▒16.7 mm Hg to 11.9 ▒4.9 mm Hg, p < 0.001). The LV ejection fraction (LVEF) significantly increased in both short-term and long-term follow-up (57 ▒14% vs. 59 ▒13%, p < 0.001 and 56 ▒14% vs. 60 ▒12%, p < 0.001, respectively). Significant regression of interventricular septum diameter at end-diastole (IVSDD) and end-diastolic posterior wall thickness (EDPWth) was noted in early (15.0 ▒2.4 mm vs. 14.5 ▒2.3 mm, p < 0.001 and 12.7 ▒2.1 mm vs. 12.4 ▒1.9 mm, p < 0.028, respectively) and late post-TAVI period (15.1 ▒2.5 mm to 14.3 ▒2.5 mm, p < 0.001 and 12.8 ▒2.0 mm to 12.4 ▒1.9 mm, p < 0.007, respectively). Significant paravalvular leak (PL) was noted in 21 (13.1%) patients immediately after TAVI and in 13 (9.6%) patients in follow-up (p < 0.001). Moderate or severe mitral regurgitation (msMR) was seen in 24 (14.9%) patients from the initial group and in 19 (11.8%) patients after TAVI (p < 0.001). Conclusions The TAVI had an immediate beneficial effect on LVEF, LV walls thickness, and the incidence of msMR. The results of the procedure are comparable with those described in other centres.
Szyma?ski, Piotr; D?browski, Maciej; Zakrzewski, Dariusz; Micha?ek, Piotr; Or?owska-Baranowska, Ewa; El-Hassan, Kamal; Chmielak, Zbigniew; Witkowski, Adam; Hryniewiecki, Tomasz
Thickness dependent sensing mechanism in sorted semi-conducting single walled nanotube based sensors.
Single walled carbon nanotube (SWCNT) networks present outstanding potential for the development of SWCNT-based gas sensors. Due to the complexity of the transport properties of this material, the physical mechanisms at stake during exposure to gas are still under debate. Previously suggested mechanisms are charge transfer between gas molecules and SWCNT and Schottky barrier modulation. By comparing electrical measurements with an analytical model based on Schottky barrier modulation, we demonstrate that one mechanism or the other is predominant depending on the percolation of metallic carbon nanotubes. Below the metallic SWCNT percolation threshold, sensing is dominated by the modulation of the Schottky barrier, while above this threshold, it is only attributed to a charge transfer between SWCNT and gas molecules. Both mechanisms are discussed in terms of sensitivity and resolution leading to routes for the optimization of a gas sensor architecture based on highly enriched semiconducting carbon nanotube films. PMID:22413126
Battie, Yann; Gorintin, Louis; Ducloux, Olivier; Thobois, Philippe; Bondavalli, Paolo; Feugnet, Gilles; Loiseau, Annick
Uncertainty induced by chest wall thickness assessment methods on lung activity estimation for plutonium and americium: a large population-based study.
In vivo lung counting aims at assessing the retained activity in the lungs. The calibration factor relating the measured counts to the worker's specific retained lung activity can be obtained by several means and strongly depends on the chest wall thickness. Here we compare, for 374 male nuclear workers, the activity assessed with a reference protocol, where the material equivalent chest wall thickness is known from ultrasound measurements, with two other protocols. The counting system is an array of four germanium detectors.It is found that non site-specific equationsĀfor the assessment of the chest wall thickness induce large biases in the assessment of activity. For plutonium isotopes or (241)Am the proportion of workers for whom the retained activity is withinĀ▒Ā10% of the reference one is smaller than 10%.The use of site-specific equationsĀraises this proportion to 20% and 58% for plutonium and (241)Am, respectively.Finally, for the studied population, when site-specific equationsĀare used for the chest wall thickness, the standard uncertainties for the lung activity are 42% and 12.5%, for plutonium and (241)Am, respectively. Due to the relatively large size of the studied population, these values are a relatively robust estimate of the uncertainties due to the assessment of the chest wall thickness for the current practice at this site. PMID:25517347
Broggio, D; Lechaftois, X; Franck, D
Angiotensinogen gene M235T polymorphism and reduction in wall thickness in response to antihypertensive treatment.
The angiotensinogen M235T polymorphism has been linked to hypertension and cardiovascular disease. Carotid intima-media thickness (IMT) is an early marker of atherosclerosis. The objectives of the present study were to determine in previously untreated essential hypertensive patients whether carotid IMT was associated with the M235T polymorphism, and to determine whether the M235T polymorphism could influence the reduction of carotid IMT by antihypertensive treatment. Common carotid artery IMT was determined with a high-definition echotracking system in 98 previously untreated hypertensive patients in a cross-sectional study. A subgroup of 56 patients was included in a randomized double-blind parallel group study comparing the effect of the angiotensin-converting-enzyme-inhibitor enalapril with that of the beta-blocker celiprolol during a 5 month period. In the cross-sectional study, a multivariate analysis showed that the M235T genotype was a significant independent determinant of carotid IMT, explaining 7% of the variance. Carotid IMT was higher in patients homozygous for the T allele than in MM patients. In the longitudinal study, the reduction in carotid IMT after antihypertensive treatment was significantly ( P <0.01) higher in patients carrying the TT genotype than in patients carrying the MM genotype, despite similar reductions in blood pressure and independently of drug type. In conclusion, these data suggest that the angiotensinogen TT genotype at position 235 is a genetic marker for early carotid atherosclerosis in a hypertensive population and its regression under antihypertensive treatment. PMID:12911327
Bozec, Erwan; Fassot, Cķline; Tropeano, Anne-Isabelle; Boutouyrie, Pierre; Jeunemaitre, Xavier; Lacolley, Patrick; Dabire, Hubert; Laurent, Stķphane
Viscoelastic fluid flow in a 2D channel bounded above by a deformable finite thickness elastic wall
The steady flow of three viscoelastic fluids (Oldroyd-B, FENE-P, and Owens model for blood) in a two-dimensional channel, partly bound by a deformable, finite thickness neo-Hookean solid, is computed. The limiting Weissenberg number beyond which computations fail to converge is found to increase with increasing dimensionless solid elasticity parameter {\\Gamma}, following the trend Owens > FENE- P > Oldroyd-B. The highly shear thinning nature of Owens model leads to the elastic solid always collapsing into the channel, for the wide range of values of {\\Gamma} considered here. In the case of the FENE-P and Oldroyd-B models, however, the fluid-solid interface can be either within the channel, or bulge outwards, depending on the value of {\\Gamma}. This behaviour differs considerably from predictions of earlier models that treat the deformable solid as a zero-thickness membrane, in which case the membrane always lies within the channel. The capacity of the solid wall to support both pressure and shear stress, in c...
Chakraborty, Debadi
Analysis of the effect of osteon diameter on the potential relationship of osteocyte lacuna density and osteon wall thickness.
An important hypothesis is that the degree of infilling of secondary osteons (Haversian systems) is controlled by the inhibitory effect of osteocytes on osteoblasts, which might be mediated by sclerostin (a glycoprotein produced by osteocytes). Consequently, this inhibition could be proportional to cell number: relatively greater repression is exerted by progressively greater osteocyte density (increased osteocytes correlate with thinner osteon walls). This hypothesis has been examined, but only weakly supported, in sheep ulnae. We looked for this inverse relationship between osteon wall thickness (On.W.Th) and osteocyte lacuna density (Ot.Lc.N/B.Ar) in small and large osteons in human ribs, calcanei of sheep, deer, elk, and horses, and radii and third metacarpals of horses. Analyses involved: (1) all osteons, (2) smaller osteons, either ?150 ?m diameter or less than or equal to the mean diameter, and (3) larger osteons (>mean diameter). Significant, but weak, correlations between Ot.Lc.N/B.Ar and On.W.Th/On.Dm (On.Dm = osteon diameter) were found when considering all osteons in limb bones (r values -0.16 to -0.40, P < 0.01; resembling previous results in sheep ulnae: r = -0.39, P < 0.0001). In larger osteons, these relationships were either not significant (five/seven bone types) or very weak (two/seven bone types). In ribs, a negative relationship was only found in smaller osteons (r = -0.228, P < 0.01); this inverse relationship in smaller osteons did not occur in elk calcanei. These results do not provide clear or consistent support for the hypothesized inverse relationship. However, correlation analyses may fail to detect osteocyte-based repression of infilling if the signal is spatially nonuniform (e.g., increased near the central canal). PMID:21809466
Skedros, John G; Clark, Gunnar C; Sorenson, Scott M; Taylor, Kevin W; Qiu, Shijing
Evolution of aortic wall thickness and stiffness with atherosclerosis: long-term follow up from the multi-ethnic study of atherosclerosis.
The study was performed to determine age, sex, and time-dependent changes in aortic wall thickness (AWT) and to evaluate cross-sectional associations between AWT and arterial stiffness in older adults. Three hundred seventy-one longitudinal and 426 cross-sectional measurements of AWT from cardiovascular magnetic resonance imaging studies conducted within the Multi-Ethnic Study of Atherosclerosis were analyzed at 2 points in time, in 2000 to 2002 and then again from follow-up examinations in 2010 to 2012. Aortic wall thickness was determined from a double inversion recovery black-blood fast spin-echo sequence, and aortic stiffness was measured from a phase-contrast cine gradient echo sequence. The thickness of the midthoracic descending aortic wall was measured and correlated to distensibility of the ascending aorta and aortic pulse wave velocity. The average rate of AWT change was 0.032 mm/y. The increase in AWT was greater for those aged 45 to 54 years relative to individuals older than 55 years (P trend<0.001). Ascending aortic distensibility was lower (P<0.001) and pulse wave velocity was higher (P=0.012) for hypertensive subjects. After adjustment for traditional risk factors, distensibility of the ascending aorta was significantly related to AWT in participants without hypertension. Hypertension was associated with increased aortic stiffness independent of aortic wall thickness. PMID:25776078
Liu, Chia-Ying; Chen, Doris; Bluemke, David A; Wu, Colin O; Teixido-Tura, Gisela; Chugh, Atul; Vasu, Sujethra; Lima, JoŃo A C; Hundley, W Gregory
January 12, 2005 Bone Thickness Name Part I. In general, bones with thicker walls are stronger and heavier, and bones with thinner
thickness of the limb bones in 5 animals: alligators, chickens, cows, humans, and the giant dinosaur to the K values you expect to find. The five animals are: alligator, chicken, cow, human, Stegosaurus bones with thin walls." Alligator Chicken Cow Human Stegosaurus Part II. Measure the bones and calculate
California at Berkeley, University of
A tale of two neglected systemsŚstructure and function of the thin- and thick-walled sieve tubes in monocotyledonous leaves
There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate, and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled) and late (thick-walled) sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma (VP) cells, whilst the late metaphloem, contains thick-walled sieve tubes (TSTs) that lack companion cells. TSTs are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube (ST) -companion cell complexes, TSTs are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the STs. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5¢7 million years old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer. PMID:23964280
Botha, C. E. J.
Phase-conjugate holographic system for high-resolution particle image velocimetry through thick-walled curved windows
NASA Astrophysics Data System (ADS)
A phase-conjugate holographic measurement system has been developed for the study of 3D fluid velocity fields. The recording system produces 3D particle images with resolution, signal-to-noise ratio, accuracy, and derived velocity fields that are comparable to high-quality 2D photographic PIV (particle image velocimetry). The high image resolution is accomplished by using low f-number optics, a fringe stabilized processing chemistry, and a phase conjugate play-back geometry that compensates for aberrations in the imaging system. In addition, the system employs a reference multiplexed, off-axis geometry for determining velocity directions using the cross-correlation technique, and a stereo camera geometry for determining the three velocity components. The combination of the imaging and reconstruction sub-systems make the analysis of volumetric PIV domains feasible. Recently, a new geometry for the HPIV system has been developed for imaging flows through thick-walled, curved windows. In the older geometry, there have been two sources inhibiting the use of windows: window scattering and window-induced aberrations. In the new system, these difficulties are avoided using side- scatter illumination of the particles and phase-conjugate reconstruction with a substitute window in place.
Barnhart, Donald H.; Adrian, Ronald J.; Menhart, Carl; Papen, George C.
Mechanical Performance and Failure Mechanism of Thick-walled Composite Connecting Rods Fabricated by Resin Transfer Molding Technique
NASA Astrophysics Data System (ADS)
A resin transfer molding technique was used to fabricate thick-walled composite connecting rods, and then the mechanical performance of the connecting rod was studied experimentally, at the same time the stress and failure index distributions were simulated numerically. The experimental results show that under a tensile load, the connecting rod first cracks near the vertex of the triangle areas at the two ends, and then the damage propagates along the interface between the main bearing beam and the triangle area as well as along the round angle of the triangle area. Whereas under a compressive load, the delamination primarily occurs at the corner of the U-shaped flange, and the final destruction is caused by the fracture of fibers in the main bearing beam. The simulated results reveal that the tensile failure is originated from the delamination at the round angle transition areas of the T-joints, and the failure strength is determined by the interlaminar strength. Whereas the compressive failure is caused by the fracture of fibers in the main bearing beam, and the failure strength of the structure is determined by the longitudinal compressive strength of the composite material. The simulated results are basically consistent with the experimental results. Hence the mechanical performance and failure mechanism of the complicated composite structure are revealed in great detail through the coupling of the two kinds of research methods, which is helpful for the optimal design of composite structures.
Liu, Gang; Luo, Chuyang; Zhang, Daijun; Li, Xueqin; Qu, Peng; Sun, Xiaochen; Jia, Yuxi; Yi, Xiaosu
Experimental and numerical study of fatigue crack propagation in a thick-walled cylinder under cyclic hoop stress
NASA Astrophysics Data System (ADS)
In present work, after finding the anisotropy resulting in dissimilar properties in different orientations of a thick-walled cylinder, experimental and numerical study was performed to reveal the fatigue crack growth behavior of the cylinder under cyclic hoop stress. Fatigue crack growth experiments were conducted on middle tension M(T) samples prepared in an orientation to simulate the hoop stress on the cylinder. The tests were conducted under constant amplitude loading at R ratio 0.1. The fatigue crack growth data was compiled and applied to simulate and predict the crack growth process using two dimensional parametric finite element technique. The fatigue crack propagation was simulated, based on linear elastic fracture mechanics and stress intensity factor determination. Both the experimental and numerical results of crack growth data, at stress levels of 10 to 40 per cent of the yield stress of the material, were found in close agreement. The disparity observed was concluded in the range of statistical scatter in the experimental data. The crack growth rate and the fatigue life of the samples obtained from the experiments and the simulation were also in good agreement at all the stress levels analyzed.
Salam, I.; Malik, M. A.; Abid, M.; Farooque, M.
Welding for testability: An approach aimed at improving the ultrasonic testing of thick-walled austenitic and dissimilar metal welds
Austenitic and dissimilar welds in thick walled components show a coarse grained, dendritic microstructure. Therefore, ultrasonic testing has to deal with beam refraction, scattering and mode conversion effects. As a result, the testing techniques typically applied for isotropic materials yield dissatisfying results. Most approaches for improvement of ultrasonic testing have been based on modeling and improved knowledge of the complex wave propagation phenomena. In this paper, we discuss an alternative approach: is it possible to use a modified welding technology which eliminates the cause of the UT complications, i.e. the large-grained structure of the weld seams? Various modification parameters were tested, including: TIG current pulsing, additional DC and AC magnetic fields, and also additional external vibrations during welding. For all welds produced under different conditions, the grain structure of the weld seam was characterized by optical and GIUM microstructure visualizations on cross sections, wave field propagation measurements, and ultrasonic tests of correct detectability of flaws. The mechanical properties of the welds were also tested.
Wagner, Sabine; Dugan, Sandra [Materials Testing Institute University of Stuttgart (MPA), Pfaffenwaldring 32, 70569 Stuttgart (Germany); Barth, Martin; Schubert, Frank; K÷hler, Bernd [Fraunhofer Institute for Nondestructive Testing, Dresden Branch (IZFP-D), Maria-Reiche-Str. 2, 01109 Dresden (Germany)
Ultrasonographic characteristics of the abdominal esophagus and cardia in dogs.
Differential diagnoses for regurgitation and vomiting in dogs include diseases of the gastroesophageal junction. The purpose of this cross-sectional study was to describe ultrasonographic characteristics of the abdominal esophagus and gastric cardia in normal dogs and dogs with clinical disease involving this region. A total of 126 dogs with no clinical signs of gastrointestinal disease and six dogs with clinical diseases involving the gastroesophageal junction were included. For seven euthanized dogs, ultrasonographic features were also compared with gross pathology and histopathology. Cardial and abdominal esophageal wall thicknesses were measured ultrasonographically for all normal dogs and effects of weight, sex, age, and stomach filling were tested. Five layers could be identified in normal esophageal and cardial walls. The inner esophageal layer was echogenic, corresponding to the cornified mucosa and glandular portion of the submucosa. The cardia was characterized by a thick muscularis, and a transitional zone between echogenic esophageal and hypoechoic gastric mucosal layers. Mean (▒SD) cardial wall thicknesses for normal dogs were 7.6 mm (▒1.6), 9.7 mm (▒1.8), 10.8 mm (▒1.6), 13.3 mm (▒2.5) for dogs in the <10 kg, 10-19.9 kg, 20-29.9 kg and ?30 kg weight groups, respectively. Mean (▒SD) esophageal wall thicknesses were: 4.1 mm (▒0.6), 5.1 mm (▒1.3), 5.6 mm (▒1), and 6.4 mm (▒1.1) for the same weight groups, respectively. Measurements of wall thickness were significantly correlated with dog weight group. Ultrasonography assisted diagnosis in all six clinically affected dogs. Findings supported the use of transabdominal ultrasonography as a diagnostic test for dogs with suspected gastroesophageal disease. PMID:24629089
Gory, Guillaume; Rault, Delphine N; Gatel, Laure; Dally, Claire; Belli, Patrick; Couturier, Laurent; Cauvin, Eddy
Method and Apparatus to Produce and Maintain a thick, flowing, Liquid Lithium first wall for Toroidal Magnetic Confinement DT Fusion Reactors
A system for forming a thick flowing liquid metal, in this case lithium, layer on the inside wall of a toroid containing the plasma of a deuterium-tritium fission reactor. The presence of the liquid metal layer or first wall serves to prevent neutron damage to the walls of the toroid. A poloidal current in the liquid metal layer is oriented so that it flows in the same direction as the current in a series of external magnets used to confine the plasma. This current alignment results in the liquid metal being forced against the wall of the toroid. After the liquid metal exits the toroid it is pumped to a heat extraction and power conversion device prior to being reentering the toroid.
Woolley, Robert D.
Method and apparatus to produce and maintain a thick, flowing, liquid lithium first wall for toroidal magnetic confinement DT fusion reactors
A system for forming a thick flowing liquid metal, in this case lithium, layer on the inside wall of a toroid containing the plasma of a deuterium-tritium fusion reactor. The presence of the liquid metal layer or first wall serves to prevent neutron damage to the walls of the toroid. A poloidal current in the liquid metal layer is oriented so that it flows in the same direction as the current in a series of external magnets used to confine the plasma. This current alignment results in the liquid metal being forced against the wall of the toroid. After the liquid metal exits the toroid it is pumped to a heat extraction and power conversion device prior to being reentering the toroid.
Woolley, Robert D. (Hillsborough, NJ)
Intraperitoneal tension-free repair of a small midline ventral abdominal wall hernia: randomized study with a mean follow-up of 3 years.
Funding received from Cousin Biotech, Wervicq Sud, France, and CR Bard Inc., Cranston, RI. The aim of this prospective randomized study was to determine the long-term recurrence and complication rates after small abdominal wall hernia repair with two different bilayer prostheses. Hernia repair using prosthetic mesh material has become the preferred method of repair, because the recurrence rates are much lower than with conventional repair techniques. The use of a hernia bilayer patch, composite expanded polytetrafluoroethylene (ePTFE)-polypropylene, with intraperitoneal placement behind the hernia defect, through a small incision, may be efficient, safe, and cost-effective. This study is a randomized, single-institution trial, including 83 selected consecutive patients with primary (umbilical, epigastric) or incisional anterior abdominal wall defects from 2 to 5 cm. Hernia repair was performed by direct local access in ambulatory surgery; the prosthesis used was a circular bilayer with an inner face in ePTFE to avoid bowel adhesion. One group was treated with a Ventralex« Hernia Patch (Bard USA). The second group was treated with a Cabs'Air« Composite (Cousin Biotech France), which was delivered with two to four fixation sutures and a balloon to properly deploy the mesh intraperitoneally. Patients' characteristics and operative and postoperative data were prospectively collected. The primary outcome was late recurrence. Secondary outcomes included, pain, discomfort and quality of life before and after (3 months) surgery using the SF-12 questionnaire, patient-surgeon satisfaction, and early and late complications. Among 98 patients, 83 were included in the study protocol between January 2007 and August 2011. The two groups were comparable according to pre- and intraoperative data. According to surgeon experience, placement of the Cabs'Air« device was significantly faster (P = 0.01) and easier. At 3 months, there was significantly less pain and less discomfort for the Cabs'Air« group and patient satisfaction rate was higher. This was confirmed by all components of the SF-12 questionnaire. Long-term follow-up was available for 77 patients. The mean follow-up was similar for the two groups (42 months; range, 14 to 70 months). At this point, for the Ventralex« group, there were four recurrences (11.7%); one mesh infection; one small bowel obstruction; and six cases (15.7%) of severe pain resulting from a mass syndrome (shrinkage) with a sense of the presence of a foreign body. Six reoperations (15.6%) were required with explant of the prosthesis. There were no recurrences or late complications in the comparative group. The Ventralex« Hernia Patch is associated with inconsistent deployment, spreading, or shrinkage, which account for late complications and decreases the overlap, which contributes to the recurrence rate. The Cabs'Air«-associated balloon facilitates superior deployment of the prosthesis allowing for good fixation with four sutures. PMID:24401516
Bensaadi, Hocine; Paolino, Luca; Valenti, Antonio; Polliand, Claude; Barrat, Christophe; Champault, Gķrard
A historically controlled, single-arm, multi-centre, prospective trial to evaluate the safety and efficacy of MonoMax« suture material for abdominal wall closure after primary midline laparotomy. ISSAAC-Trial [NCT005725079
Background Several randomized controlled trials have compared different suture materials and techniques for abdominal wall closure with respect to the incidence of incisional hernias after midline laparotomy and shown that it remains, irrespective of the methods used, considerably high, ranging from 9% to 20%. The development of improved suture materials which would reduce postoperative complications may help to lower its frequency. Design This is a historically controlled, single-arm, multi-centre, prospective trial to evaluate the safety of MonoMax« suture material for abdominal wall closure in 150 patients with primary elective midline incisions. INSECT patients who underwent abdominal closure using Monoplus« and PDS« will serve as historical control group. The incidences of wound infections and of burst abdomen are defined as composite primary endpoints. Secondary endpoints are the frequency of incisional hernias within one year after operation and safety. To ensure adequate comparability in surgical performance and recruitment, the 4 largest centres of the INSECT-Trial will participate. After hospital discharge, the investigators will examine the enrolled patients again at 30 days and at 12 ▒ 1 months after surgery. Conclusion This historically controlled, single-arm, multi-centre, prospective ISSAAC trial aims to assess whether the use of an ultra-long-lasting absorbable monofilament suture material is safe and efficient. Trial registration NCT005725079 PMID:18644124
Fischer, Lars; Baumann, Petra; H³sing, Johannes; Seidlmayer, Christoph; Albertsmeier, Markus; Franck, Annette; Luntz, Steffen; Seiler, Christoph M; Knaebel, Hanns-Peter
In the femoral artery bifurcation, differences in mean wall shear stress within subjects are associated with different intima-media thicknesses.
In elastic arteries, intima-media thickening is more pronounced in areas with low than with high mean and peak wall shear stress. These findings in elastic arteries are not necessarily representative of the situation in muscular arteries. The former arteries have to store volume energy, whereas the latter are mainly conductive vessels. It was the aim of the present study to investigate noninvasively whether differences in wall shear stress within a muscular artery bifurcation, if any, were associated with different intima-media thicknesses (IMTs). The effect of age on the possible differences was assessed as well. We determined IMT and mean, peak systolic, and the maximum cyclic change in shear stress near the posterior wall in the common (FC) and the superficial (FS) femoral artery 20 to 30 mm from the flow divider in 54 presumed healthy subjects between 21 and 74 years of age. Results were considered in terms of intrasubject differences. Before the study, the reliability of the ultrasonic system to assess wall shear rate and IMT was determined in terms of intrasubject variability. IMT at the posterior wall was significantly larger in the FC than in the FS, probably owing to the significantly lower mean wall shear stress at this site in the FC. The relative differences in IMT and mean wall shear stress between FC and FS were independent of age. The difference in wall shear stress between both arteries can likely be explained by a different influence of reflections. In both the FC and FS, mean, peak systolic, and maximum cyclic change in shear stress near the posterior wall did not change significantly with age, whereas IMT did increase significantly with age. PMID:10591672
Kornet, L; Hoeks, A P; Lambregts, J; Reneman, R S
Reconstruction option of abdominal wounds with large tissue defects
Background Abdominal wall defects result from trauma, abdominal wall tumors, necrotizing infections or complications of previous abdominal surgeries. Apart from cosmetics, abdominal wall defects have strong negative functional impact on the patients. Many different techniques exist for abdominal wall repair. Most problematic and troublesome are defects, where major part of abdominal wall had to be resected and tissue for transfer or reconstruction is absent. Case presentation Authors of the article present operative technique, in which reconstruction of abdominal wall was managed by composite polypropylene mesh with absorbable collagen film, creation of granulation tissue with use of NPWT (negative pressure wound therapy), and subsequent split skin grafting. Three patients with massive abdominal wall defect were successfully managed and abdominal wall reconstruction was performed by mentioned technique. Functional and cosmetic effect is acceptable and patients have good postoperative quality of life. Conclusions Patients with giant abdominal defects can benefit from described technique. It serves as the only option, with which abdominal wall is fully reconstructed without need for the secondary intervention. PMID:25103782
... procedure is done most often to test for amyloidosis . ... This test may be performed when amyloidosis is suspected. ... In the case of amyloidosis, abnormal results mean there is amyloid, a protein that deposits in tissues and impairs organ and tissue function.
New Formulas for Mutual Inductance and Axial Magnetic Force Between a Thin Wall Solenoid and a Thick Circular Coil of Rectangular Cross-Section
This paper presents new analytic formulas for determining the mutual inductance and the axial magnetic force between two coaxial coils in air, namely a thick circular coil with rectangular cross-section and a thin wall solenoid. The mutual inductance and the magnetic force are expressed as complete elliptical integrals of the first and second kind, HeumanÆs Lambda function and one well-behaved
Slobodan Babic; Frķdķric Sirois; Cevdet Akyel; Guy Lemarquand; Valķrie Lemarquand; Romain Ravaud
Effects of Mechanical Vibration and Wall Thickness on Microstructure and Mechanical Properties of AZ91D Magnesium Alloy Processed by Expendable Pattern Shell Casting
NASA Astrophysics Data System (ADS)
Mechanical vibration was introduced into the solidification process of AZ91D magnesium alloy during the expendable pattern shell casting process, and the combined effects of mechanical vibration and wall thickness on the microstructure and mechanical properties were investigated. The results indicate that with the increase of wall thickness, the morphologies in ?-Mg phase and ?-Mg17Al12 phase of the samples obtained without vibration evolved from a fine dendrite to a coarse dendrite and from a fine continuous network structure to a coarse continuous network structure, respectively, and the mechanical properties and density of AZ91D alloy continuously decreased. With the application of mechanical vibration, the coarser dendrites transformed into fine equiaxed grains, and the previous coarse continuous network structure of the ?-Mg17Al12 phase was changed to a discontinuous granular morphology. Meanwhile, the mechanical properties and density of AZ91D alloy greatly increased. The effect of mechanical vibration on the microstructure and mechanical properties increased with increasing vibration frequency and wall thickness. The fractographs of the tensile samples show a change in fracture surface from brittle to that of a tough fracture with the addition of vibration.
Jiang, Wenming; Fan, Zitian; Chen, Xu; Wang, Benjing; Wu, Hebao
Stomach pain; Pain - abdomen; Belly ache; Abdominal cramps; Bellyache; Stomachache ... Almost everyone has pain in the abdomen at some point. Most of the time, it is not serious. How bad your pain is does not always reflect the seriousness ...
Acute incarcerated external abdominal hernia.
External abdominal hernia occurs when abdominal organs or tissues leave their normal anatomic site and protrude outside the skin through the congenital or acquired weakness, defects or holes on the abdominal wall, including inguinal hernia, umbilical hernia, femoral hernia and so on. Acute incarcerated hernia is a common surgical emergency. With advances in minimally invasive devices and techniques, the diagnosis and treatment have witnessed major changes, such as the use of laparoscopic surgery in some cases to achieve minimally invasive treatment. However, strict adherence to the indications and contraindications is still required. PMID:25489584
Yang, Xue-Fei; Liu, Jia-Lin
Acute incarcerated external abdominal hernia
External abdominal hernia occurs when abdominal organs or tissues leave their normal anatomic site and protrude outside the skin through the congenital or acquired weakness, defects or holes on the abdominal wall, including inguinal hernia, umbilical hernia, femoral hernia and so on. Acute incarcerated hernia is a common surgical emergency. With advances in minimally invasive devices and techniques, the diagnosis and treatment have witnessed major changes, such as the use of laparoscopic surgery in some cases to achieve minimally invasive treatment. However, strict adherence to the indications and contraindications is still required. PMID:25489584
Yang, Xue-Fei
A case report on a full-thickness chest wall reconstruction with polypropylene mesh and stainless steel mesh concurrently using a transverse rectus abdominis myocutaneous flap.
A full-thickness chest wall resection requires subsequent chest wall reconstruction. A chest wall resection and reconstruction was performed using a transverse rectus abdominis myocutaneous (TRAM) flap, together with polypropylene mesh (Marlex mesh) and stainless steel mesh (SSM). A 71-year-old man was diagnosed as having recurrent lung cancer in the chest wall, and underwent surgical resection. Marlex mesh was sutured to the posterior wall of the surgical defect. A portion of the SSM was adjusted to the size of the defect and cut out. Its edges were folded to make the portion into a plate. This SSM plate was placed anteriorly to the Marlex mesh and sutured to the ribs. The Marlex mesh was folded back on the SSM plate by 2 cm and fixed. After the above procedures, a left-sided TRAM flap was raised through a subcutaneous tunnel up to the defect and sutured to the region. The patient was discharged from hospital 19 days postoperatively. The wound was fine and he had no flail chest or dyspnea, and carcinomatous pain resolved. PMID:17228288
Yoshino, Naoyuki; Yamauchi, Shigeo; Akimoto, Masataka; Hisayoshi, Takao; Koizumi, Kiyoshi; Shimizu, Kazuo
Abdominal Mondor's disease presenting as acute abdominal pain.
We describe here the case of 41 yrs old male patient, who was admitted to the emergency department complaining for abdominal pain lasting for two days. The patient self-reported a history of idiopathic deep vein thrombosis five yrs before the visit. A subcutaneous cordlike induration, tender and painful, was clearly palpable in the left lower abdominal quadrant. Routine blood tests did not reveal any substantial abnormality, except increased D-dimer concentration. Ultrasound evaluation of the abdominal wall revealed diffuse thrombosis of the left superficial inferior epigastric vein, involving several small tributaries branches, extended until 1.5 cm from the confluence with the common femoral vein, which was finally classified as an atypical case of Abdominal Mondor's disease. Complete thrombophilia screening was negative. The patient was discharged with warfarin therapy 48 hours from admission. At 30 days follow-up, the patient self-reported a nearly complete recovery. PMID:24165464
Cervellin, Gianfranco; Creta, Michele; Riva, Michele; Di Comite, Vincenzo; Buttarelli, Lorenzo; Lippi, Giuseppe
Development of a Versatile Laser-Ultrasonic System and Application to the Online Measurement for Process Control of Wall Thickness and Eccentricity of Seamless Tubes
A system for the online, non-contact measurement of wall thickness in steel seamless mechanical tubing has been developed and demonstrated at a tubing production line at the Timken Company in Canton, Ohio. The system utilizes laser-generation of ultrasound and laser-detection of time of flight with interferometry, laser-doppler velocimetry and pyrometry, all with fiber coupling. Accuracy (<1% error) and precision (1.5%) are at targeted levels. Cost and energy savings have exceeded estimates. The system has shown good reliability in measuring over 200,000 tubes in its first six months of deployment.
Robert V. Kolarik II
Abdominal aortic aneurysm: from clinical imaging to realistic replicas.
The goal of this work is to develop a framework for manufacturing nonuniform wall thickness replicas of abdominal aortic aneurysms (AAAs). The methodology was based on the use of computed tomography (CT) images for virtual modeling, additive manufacturing for the initial physical replica, and a vacuum casting process and range of polyurethane resins for the final rubberlike phantom. The average wall thickness of the resulting AAA phantom was compared with the average thickness of the corresponding patient-specific virtual model, obtaining an average dimensional mismatch of 180??m (11.14%). The material characterization of the artery was determined from uniaxial tensile tests as various combinations of polyurethane resins were chosen due to their similarity with ex vivo AAA mechanical behavior in the physiological stress configuration. The proposed methodology yields AAA phantoms with nonuniform wall thickness using a fast and low-cost process. These replicas may be used in benchtop experiments to validate deformations obtained with numerical simulations using finite element analysis, or to validate optical methods developed to image ex vivo arterial deformations during pressure-inflation testing. PMID:24190650
de Galarreta, Sergio Ruiz; Aitor, Caz¾n; Ant¾n, Ra·l; Finol, Ender A
Design of low alloy steels for thick walled pressure vessels. Final technical report, February 1, 1980May 30, 1985. [2-1\\/4Cr1Mo with minor additions of Cr, Ni, Mo and V
This report presents results of the five year research program ''Design of Low Alloy Steels for Thick Walled Pressure Vessels.'' The objective of the program was to modify existing commercial low alloy steels and to develop new alloys to satisfy the material requirements for thick section plate up to 400 mm (16 in.) to be used for construction of the
R. O. Ritchie; J. A. Todd; P. N. Spencer; E. R. Parker
Analysis of transient heat flow to thick-walled plates and cylinders. [to determine gas heat transfer coefficient
NASA Technical Reports Server (NTRS)
A methodology is described for the analysis of a transient temperature measurement made in a flat or curved plate subjected to convective heat transfer, such that the surface heat flux, the hot-gas temperture, and the gas heat transfer coefficient can be determined. It is shown that if the transient temperature measurement is made at a particular point located nearly midway in the thickness of the plate there is an important simplification in the data analysis process, in that the factor relating the surface heat flux to the measured rate of rise of temperature becomes invariant for a Fourier Number above 0.60 and for all values of the Biot Number. Parameters are derived, tabulated, and plotted which enable straightforward determination of the surface heat flux, the hot-gas temperature, of the plate, the rate of rise of temperature, the plate thickness and curvature, and the mean thermal properties of the plate material at the test temperature.
Powell, W. B.
Increased Infarct Wall Thickness by a Bio-Inert Material Is Insufficient to Prevent Negative Left Ventricular Remodeling after Myocardial Infarction
Background Several injectable materials have been shown to preserve or improve cardiac function as well as prevent or slow left ventricular (LV) remodeling post-myocardial infarction (MI). However, it is unclear as to whether it is the structural support or the bioactivity of these polymers that lead to beneficial effects. Herein, we examine how passive structural enhancement of the LV wall by an increase in wall thickness affects cardiac function post-MI using a bio-inert, non-degradable synthetic polymer in an effort to better understand the mechanisms by which injectable materials affect LV remodeling. Methods and Results Poly(ethylene glycol) (PEG) gels of storage modulus G??=?0.5▒0.1 kPa were injected and polymerized in situ one week after total occlusion of the left coronary artery in female Sprague Dawley rats. The animals were imaged using magnetic resonance imaging (MRI) at 7▒1 day(s) post-MI as a baseline and again post-injection 49▒4 days after MI. Infarct wall thickness was statistically increased in PEG gel injected vs. control animals (p<0.01). However, animals in the polymer and control groups showed decreases in cardiac function in terms of end diastolic volume, end systolic volume and ejection fraction compared to baseline (p<0.01). The cellular response to injection was also similar in both groups. Conclusion The results of this study demonstrate that passive structural reinforcement alone was insufficient to prevent post-MI remodeling, suggesting that bioactivity and/or cell infiltration due to degradation of injectable materials are likely playing a key role in the preservation of cardiac function, thus providing a deeper understanding of the influencing properties of biomaterials necessary to prevent post-MI negative remodeling. PMID:21731777
Rane, Aboli A.; Chuang, Joyce S.; Shah, Amul; Hu, Diane P.; Dalton, Nancy D.; Gu, Yusu; Peterson, Kirk L.; Omens, Jeffrey H.; Christman, Karen L.
Pulse Wave Imaging of Human Abdominal Aortas Jianwen Luo1
, NY, USA email@example.com Abstract-- Vascular diseases (e.g., abdominal aortic aneurysm or, AAA on the mechanical properties of the aortic wall in vivo. Keywords-abdominal aortic aneurysm; pulse wave; pulse wave. Various vascular diseases including abdominal aortic aneurysms (AAAs) are known to change the tissue
Konofagou, Elisa E.
Analysis of thermal residual stress in a thick-walled ring of Duralcan-base Al-SiC functionally graded material
A ring-cutting test and an elastic theory were applied to evaluate the macroscopic residual stress in a thick-walled ring made of Al-SiC functionally graded material (FGM). The FGM ring specimens, with outer diameter 90 mm, radial thickness approximately 8.4 to 10 mm, and width 30 mm, were fabricated by the centrifugal casting method from an ingot of Duralcan F3D.20S of Al-20 vol pct SiC master composite. Because of a difference in centrifugal forces of SiC particles and of molten aluminum alloy, the rings had a graded composition of SiC particles in the radial direction. The volume fractions of SiC particles in each ring specimen varied in the range of 0 to 43 vol pct from the inner to the outer surface of the ring, depending on the applied mold spin speed. A ring diametral compression test was performed to validate an analytical formula based on the curved beam theory that can account for the graded properties of the material. Excellent agreement between the theory that can account for the graded properties of the material. Excellent agreement between the theory and the experiment was found. The residual stress was found to be generated by a cooling of {Delta}T = 140 K, which was from half the melting point corresponding stress-free condition to the ambient temperature. The hoop residual stresses in the FGM ring varied in the range of {minus}50 to +35 MPa and from tension at the inner surface to compression at the outer space because of the graded composition. With an increase in wall thickness and/or composition gradation, the residual stresses were found to increase.
Fukui, Yasuyoshi [Kagoshima Univ. (Japan). Dept. of Mechanical Engineering; Watanabe, Yoshimi [Shinshu Univ., Ueda (Japan). Faculty of Textile Science and Technology
The growth of low resistivity, heavily Al-doped 4H-SiC thick epilayers by hot-wall chemical vapor deposition
NASA Astrophysics Data System (ADS)
Heavily Al-doped 4H-SiC thick epilayers (?90 ?m) were grown on 3-in n+ 4H-SiC wafers by using the hot-wall CVD method. On the purpose of enhancing incorporated Al-dopant concentration, the growth condition dependence of the Al incorporation behavior in the heavy doping range near Al solubility limit in 4H-SiC was investigated by varying the growth parameters, i.e., growth rate, pressure, temperature and Al-dopant source flow rate. A series of thick epilayers possessing Al-dopant concentration from 9.6ū1019 to 4.7ū1020 cm-3 were obtained. Among them, the epilayer with Al-dopant concentration of 3.5ū1020 cm-3 demonstrates a comparably low resistivity of 16.5 m? cm as that of commercial n+ 4H-SiC wafer. The incorporated Al-dopant concentration dependences on surface morphology, crystalline quality and crystal structures of the heavily Al-doped thick epilayers on n+ 4H-SiC substrates were characterized and discussed.
Ji, Shiyang; Kojima, Kazutoshi; Ishida, Yuuki; Saito, Shingo; Kato, Tomohisa; Tsuchida, Hidekazu; Yoshida, Sadafumi; Okumura, Hajime
Introduction Ostriches typically avoid humans in the wild, since they correctly assess humans as potential predators, and, if approached, often run away. However, ostriches may turn aggressive rather than run when threatened, especially when cornered, and may also attack when they feel the need to defend their offspring or territories. Presentation of case A 71-year-old male patient presented with intra abdominal injury sustained from being kicked in the abdominal wall by an ostrich. During laparotomy, were found free peritoneal effusion and perforation of the small intestine. Discussion The clinical history and physical examination are extremely important for diagnostic and therapeutic decision making. CT-scan is the most accurate exam for making diagnosis. Surgery is the treatment of choice, and is always indicated when there is injury to the hollow viscera. In general it is possible to suture the defect. Conclusion In cases of blunt abdominal trauma by animals is necessary to have a low threshold of suspicion for acute abdomen. PMID:25685344
Usurelu, Sergiu; Bettencourt, Vanessa; Melo, Gina
Estimation of PSD Shifts for High-Resolution Metrology of Thickness Micro-Changes with Possible Applications in Vessel Walls and Biological Membrane Characterization
Achieving accurate measurements of inflammation levels in tissues or thickness changes in biological membranes (e.g., amniotic sac, parietal pleura) and thin biological walls (e.g., blood vessels) from outside the human body, is a promising research line in the medical area. It would provide a technical basis to study the options for early diagnosis of some serious diseases such as hypertension, atherosclerosis or tuberculosis. Nevertheless, achieving the aim of non-invasive measurement of those scarcely-accessible parameters on patient internal tissues, currently presents many difficulties. The use of high-frequency ultrasonic transducer systems appears to offer a possible solution. Previous studies using conventional ultrasonic imaging have shown this, but the spatial resolution was not sufficient so as to permit a thickness evaluation with clinical significance, which requires an accuracy of a few microns. In this paper a broadband ultrasonic technique, that was recently developed by the authors to address other non-invasive medical detection problems (by integrating a piezoelectric transducer into a spectral measuring system), is extended to our new objective; the aim is its application to the thickness measurement of sub-millimeter membranes or layers made of materials similar to some biological tissues (phantoms). The modeling and design rules of such a transducer system are described, and various methods of estimating overtones location in the power spectral density (PSD) are quantitatively assessed with transducer signals acquired using piezoelectric systems and also generated from a multi-echo model. Their effects on the potential resolution of the proposed thickness measuring tool, and their capability to provide accuracies around the micron are studied in detail. Comparisons are made with typical tools for extracting spatial parameters in laminar samples from echo-waveforms acquired with ultrasonic transducers. Results of this advanced measurement spectral tool are found to improve the performance of typical cross-correlation methods and provide reliable and high-resolution estimations. PMID:23202216
Ramos, Antonio; Bazßn, Ivonne; Negreira, Carlos; Brum, Javier; G¾mez, Tomßs; Calßs, Hķctor; Ruiz, Abelardo; de la Rosa, Josķ Manuel
Estimation of PSD shifts for high-resolution metrology of thickness micro-changes with possible applications in vessel walls and biological membrane characterization.
Achieving accurate measurements of inflammation levels in tissues or thickness changes in biological membranes (e.g., amniotic sac, parietal pleura) and thin biological walls (e.g., blood vessels) from outside the human body, is a promising research line in the medical area. It would provide a technical basis to study the options for early diagnosis of some serious diseases such as hypertension, atherosclerosis or tuberculosis. Nevertheless, achieving the aim of non-invasive measurement of those scarcely-accessible parameters on patient internal tissues, currently presents many difficulties. The use of high-frequency ultrasonic transducer systems appears to offer a possible solution. Previous studies using conventional ultrasonic imaging have shown this, but the spatial resolution was not sufficient so as to permit a thickness evaluation with clinical significance, which requires an accuracy of a few microns. In this paper a broadband ultrasonic technique, that was recently developed by the authors to address other non-invasive medical detection problems (by integrating a piezoelectric transducer into a spectral measuring system), is extended to our new objective; the aim is its application to the thickness measurement of sub-millimeter membranes or layers made of materials similar to some biological tissues (phantoms). The modeling and design rules of such a transducer system are described, and various methods of estimating overtones location in the power spectral density (PSD) are quantitatively assessed with transducer signals acquired using piezoelectric systems and also generated from a multi-echo model. Their effects on the potential resolution of the proposed thickness measuring tool, and their capability to provide accuracies around the micron are studied in detail. Comparisons are made with typical tools for extracting spatial parameters in laminar samples from echo-waveforms acquired with ultrasonic transducers. Results of this advanced measurement spectral tool are found to improve the performance of typical cross-correlation methods and provide reliable and high-resolution estimations. PMID:23202216
Ramos, Antonio; Bazßn, Ivonne; Negreira, Carlos; Brum, Javier; G¾mez, Tomßs; Calßs, Hķctor; Ruiz, Abelardo; de la Rosa, Josķ Manuel
Sonographic findings in abdominal hereditary angioedema.
Patients with hereditary angioedema (HAE) may suffer from abdominal pain severe enough to prompt unnecessary surgical intervention. The diagnostic approach to abdominal pain during HAE attacks is not established. We describe abdominal sonographic findings during severe colic in 2 patients with known HAE. Sonography demonstrated marked mucosal thickening and edema of the bowel wall with a variable amount of free peritoneal fluid. These findings are not specific but are consistent with the hypothesized mechanism of attack and resolve after therapy. Abdominal sonography is useful for evaluating acute abdominal pain in patients with known HAE to prevent unnecessary surgery. Conversely, if the described sonographic findings appear in a case of abdominal colic of unknown origin, HAE should be included in the differential diagnosis. PMID:10525217
Sofia, S; Casali, A; Bolondi, L
Comparative study of the microvascular blood flow in the intestinal wall, wound contraction and fluid evacuation during negative pressure wound therapy in laparostomy using the V.A.C. abdominal dressing and the ABThera open abdomen negative pressure therapy system.
This study aimed to compare the changes in microvascular blood flow in the small intestinal wall, wound contraction and fluid evacuation, using the established V.A.C. abdominal dressing (VAC dressing) and a new abdominal dressing, the ABThera open abdomen negative pressure therapy system (ABThera dressing), in negative pressure wound therapy (NPWT). Midline incisions were made in 12 pigs that were subjected to treatment with NPWT using the VAC or ABThera dressing. The microvascular blood flow in the intestinal wall was measured before and after the application of topical negative pressures of ?50, ?75 and ?125mmHg using laser Doppler velocimetry. Wound contraction and fluid evacuation were also measured. Baseline blood flow was defined as 100% in all settings. The blood flow was significantly reduced to 64Ę6▒6Ę7% (P <0Ę05) after the application of ?50mmHg using the VAC dressing, and to 65Ę3▒9Ę6% (P <0Ę05) after the application of ?50mmHg using the ABThera dressing. The blood flow was significantly reduced to 39Ę6▒6Ę7% (P <0Ę05) after the application of ?125mmHg using VAC and to 40Ę5▒6Ę2% (P <0Ę05) after the application of ?125mmHg using ABThera. No significant difference in reduction in blood flow could be observed between the two groups. The ABThera system afforded significantly better fluid evacuation from the wound, better drainage of the abdomen and better wound contraction than the VAC dressing. PMID:23517436
Lindstedt, Sandra; Malmsj÷, Malin; Hlebowicz, Joanna; Ingemansson, Richard
Rigidity of the abdomen ... is a sore area inside the belly or abdomen, the pain will get worse when a hand ... Abscess inside the abdomen Appendicitis Cholecystitis caused by ... the entire wall of the stomach, small intestine, large bowel, ...
Automated airway evaluation system for multi-slice computed tomography using airway lumen diameter, airway wall thickness and broncho-arterial ratio
NASA Astrophysics Data System (ADS)
Pulmonary diseases such as bronchiectasis, asthma, and emphysema are characterized by abnormalities in airway dimensions. Multi-slice computed tomography (MSCT) has become one of the primary means to depict these abnormalities, as the availability of high-resolution near-isotropic data makes it possible to evaluate airways at oblique angles to the scanner plane. However, currently, clinical evaluation of airways is typically limited to subjective visual inspection only: systematic evaluation of the airways to take advantage of high-resolution data has not proved practical without automation. We present an automated method to quantitatively evaluate airway lumen diameter, wall thickness and broncho-arterial ratios. In addition, our method provides 3D visualization of these values, graphically illustrating the location and extent of disease. Our algorithm begins by automatic airway segmentation to extract paths to the distal airways, and to create a map of airway diameters. Normally, airway diameters decrease as paths progress distally; failure to taper indicates abnormal dilatation. Our approach monitors airway lumen diameters along each airway path in order to detect abnormal profiles, allowing even subtle degrees of pathologic dilatation to be identified. Our method also systematically computes the broncho-arterial ratio at every terminal branch of the tree model, as a ratio above 1 indicates potentially abnormal bronchial dilatation. Finally, the airway wall thickness is computed at corresponding locations. These measurements are used to highlight abnormal branches for closer inspection, and can be summed to compute a quantitative global score for the entire airway tree, allowing reproducible longitudinal assessment of disease severity. Preliminary tests on patients diagnosed with bronchiectasis demonstrated rapid identification of lack of tapering, which also was confirmed by corresponding demonstration of elevated broncho-arterial ratios.
Odry, Benjamin L.; Kiraly, Atilla P.; Novak, Carol L.; Naidich, David P.; Lerallut, Jean-Francois
Steam-assisted crystallization of TPA{sup +}-exchanged MCM-41 type mesoporous materials with thick pore walls
Highlights: ? Mesoporous Ti-containing silica with thicker pore walls was synthesized. ? Ion-exchange and steam-assisted crystallization led to MCM-41/MFI composite. ? The introduction of Ti inhibited the formation of separated MFI particles. ? Lower temperature favored retaining mesoporous characteristics and morphology. -- Abstract: Hierarchical MCM-41/MFI composites were synthesized through ion-exchange of as-made MCM-41 type mesoporous materials with tetrapropylammonium bromide and subsequent steam-assisted recrystallization. The obtained samples were characterized by powder X-ray diffraction (XRD), UV¢vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis, FT-IR, {sup 1}H¢{sup 13}C CP/MAS and nitrogen adsorption¢desorption. The XRD patterns show that the MCM-41/MFI composite possesses both ordered MCM-41 phase and zeolite MFI phase. SEM and TEM images indicate that the recrystallized materials retained the mesoporous characteristics and the morphology of as-made mesoporous materials without the formation of bulky zeolite, quite different from the mechanical mixture of MCM-41 and MFI structured zeolite. Among others, lower recrystallization temperature and the introduction of the titanium to the parent materials are beneficial to preserve the mesoporous structure during the recrystallization process.
Chen, Hong Li; Zhang, Kun [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, Shanghai 200062 (China)] [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, Shanghai 200062 (China); Wang, Yi Meng, E-mail: email@example.com [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, Shanghai 200062 (China)
Novel synthesis of thick wall coatings of titania supported Bi poisoned Pd catalysts and application in selective hydrogenation of acetylene alcohols in capillary microreactors.
Catalysis in microreactors allows reactions to be performed in a very small volume, reducing the environmental problems and greatly intensifying the processes through easy pressure control and the elimination of heat- and mass-transfer limitations. In this study, we report a novel method for the controlled synthesis of micrometre-thick mesoporous TiO2 catalytic coatings on the walls of long channels (>1 m) of capillary microreactors in a single deposition step. The method uses elevated temperature and introduces a convenient control parameter of the deposition rate (displacement speed controlled by a stepper motor), which allows deposition from concentrated and viscous sols without channel clogging. A capillary microreactor wall-coated with titania supported Bi-poisoned Pd catalyst was obtained using the method and used for the semihydrogenation of 2-methyl-3-butyn-2-ol providing 93 ▒ 1.5% alkene yield for 100 h without deactivation. Although the coating method was applied only for TiO2 deposition, it is nonetheless suitable for the deposition of volatile sols. PMID:25749619
Cherkasov, Nikolay; Ibhadon, Alex O; Rebrov, Evgeny V
Differences in near-wall shear rate in the carotid artery within subjects are associated with different intima-media thicknesses.
In the common carotid artery, reflections originating from the periphery and the flow divider may affect the shape of the flow velocity profile and, hence, near-wall shear rate (WSR) differently just before the bifurcation (location B) than 20 to 30 mm farther upstream (location A). Recent developments in ultrasound technology allow the assessment of WSR and intima-media thickness (IMT) at the same site in the carotid artery in vivo. We therefore determined WSR at locations A and B and investigated whether the differences between both sites, if any, were associated with different IMTs and different mechanical properties of the arterial wall. The effect of age on the possible differences was assessed as well. The study was performed on presumably healthy volunteers (n=53). In all individuals, IMT was larger at location B than at location A. The relative difference in IMT between both locations was not affected by age. No significant differences in diameter and distension were found between locations. Near peak systolic and near mean WSR at the posterior wall (PWSRp and MWSRp, respectively) were significantly lower at location B than at location A. The relative differences in PWSRp and MWSRp between both locations within subjects were independent of age. The velocity profiles were more blunted at location A than at location B. PWSRp and MWSRp significantly decreased and IMT significantly increased with age at both locations. IMT was negatively correlated with PWSRP and MWSRP at location B, but this correlation was not significant at location A. In summary, in the common carotid artery, the lower WSR near the bifurcation, as compared with 20 to 30 mm upstream, is associated with a larger IMT than at the more proximal site. The relative difference between both locations within subjects is independent of age. PMID:9848879
Kornet, L; Lambregts, J; Hoeks, A P; Reneman, R S
Traumatic abdominal hernia complicated by necrotizing fasciitis.
Necrotizing fasciitis is a critical illness involving skin and soft tissues, which may develop after blunt abdominal trauma causing abdominal wall hernia and representing a great challenge for physicians. A 52-year-old man was brought to the emergency department after a road accident, presenting blunt abdominal trauma with a large non-reducible mass in the lower-right abdomen. A first, CT showed abdominal hernia without signs of complication. Three hours after ICU admission, he developed hemodynamic instability. Therefore, a new CT scan was requested, showing signs of hernia complication. He was moved to the operating room where a complete transversal section of an ileal loop was identified. Five hours after surgery, he presented a new episode of hemodynamic instability with signs of skin and soft tissue infection. Due to the high clinical suspicion of necrotizing fasciitis development, wide debridement was performed. Following traumatic abdominal wall hernia (TAWH), patients can present unsuspected injuries in abdominal organs. Helical CT can be falsely negative in the early moments, leading to misdiagnosis. Necrotizing fasciitis is a potentially fatal infection and, consequently, resuscitation measures, wide-spectrum antibiotics, and early surgical debridement are required. This type of fasciitis can develop after blunt abdominal trauma following wall hernia without skin disruption. PMID:25541927
MartĒnez-Pķrez, Aleix; Garrig¾s-Ortega, Gonzalo; G¾mez-Abril, Segundo ┴ngel; MartĒ-MartĒnez, Eva; Torres-Sßnchez, Teresa
Gastric tonometry and direct intraabdominal pressure monitoring in abdominal compartment syndrome
Background\\/Purpose: Abdominal compartment syndrome (ACS) may complicate abdominal closure in patients with abdominal wall defects, abdominal trauma, intraperitoneal bleeding, and infection. Increased intraabdominal pressure (IAP) leads to respiratory compromise, organ hypoperfusion, and a high mortality rate. This study evaluates the efficacy of continuous direct monitoring of IAP and gastric tissue pH in detecting impending ACS. Methods: Ten mongrel puppies weighing
S. A. Engum; B. Kogon; E. Jensen; J. Isch; C. Balanoff; J. L. Grosfeld
International Angiology Title: Studying the Expansion of Small Abdominal Aortic Aneurysms: Is There a
the Expansion of Small Abdominal Aortic Aneurysms: Is There a Role for Peak Wall Stress? Paper code: Int Angiol 95 #12;1 Studying the Expansion of Small Abdominal Aortic Aneurysms: Is There a Role for Peak Wall practice a definition for Abdominal Aortic Aneurysm (AAA) as a tr
Papaharilaou, Yannis
Effects of the changes in the wall shear stresses (WSS) acting on endothelial cells (EC) during the enlargement of Abdominal Aortic Aneurysms (AAA)
NASA Astrophysics Data System (ADS)
The changes in the spatial and temporal distribution of the WSS and gradients of WSS during the enlargement of AAAs are important to understand the etiology and progression of this vascular disease, since they affect the wall structural integrity, primarily via the changes induced on the shape, functions and metabolism of the endothelial cells. PIV measurements were performed in aneurysm models, while changing systematically their size and geometry. Two regions with distinct patterns of WSS were identified. The region of flow detachment extends over the proximal half and is characterized by oscillatory WSS of very low mean. The region of flow reattachment, located distally, is dominated by large, negative WSS and sustained gradients of WSS that result from the impact of the vortex ring on the wall. Cultured EC were subjected to these two types of stimuli in vitro. The permeability of the endothelium was found to be largely increased in the flow detachment region. Endothelium cell-cell adhesion, proliferation and apoptosis were also affected by the high gradients of WSS.
Salsac, Anne-Virginie
Observations on intra-abdominal pressure and patterns of abdominal intra-muscular activity in man.
The aim was to investigate possible relationships between activities of the individual muscles of the ventrolateral abdominal wall and the development of pressure within the abdominal cavity. Intra-muscular activity was recorded bilaterally from transversus abdominis, obliquus internus, obliquus externus and rectus abdominis with fine-wire electrodes guided into place using real-time ultrasound. Intra-abdominal pressure was measured intragastrically using a micro tip pressure transducer. Six males were studied during loading and movement tasks with varied levels of intra-abdominal pressure. During both maximal voluntary isometric trunk flexion and extension, transversus abdominis activity and intra-abdominal pressure remained constant, while all other abdominal muscles showed a marked reduction during extension. When maximal isometric trunk flexor or extensor torques were imposed upon a maximal Valsalva manoeuvre, transversus abdominis activity and intra-abdominal pressure remained comparable within and across conditions, whereas obliquus internus, obliquus externus and rectus abdominis activities either markedly increased (flexion) or decreased (extension). Trunk twisting movements showed reciprocal patterns of activity between the left and right sides of transversus abdominis, indicating an ability for torque development. During trunk flexion--extension, transversus abdominis showed less distinguished changes of activity possibly relating to a general stabilizing function. In varied pulsed Valsalva manoeuvres, changes in peak intra-abdominal pressure were correlated with mean amplitude electromyograms of all abdominal muscles, excluding rectus abdominis. It is concluded that the co-ordinative patterns shown between the muscles of the ventrolateral abdominal wall are task specific based upon demands of movement, torque and stabilization. It appears that transversus abdominis is the abdominal muscle whose activity is most consistently related to changes in intra-abdominal pressure. PMID:1534959
Cresswell, A G; Grundstr÷m, H; Thorstensson, A
Copper(II) ion selective and strong acid-tolerable hydrogels formed by an L-histidine ester terminated bolaamphiphile: from single molecular thick nanofibers to single-wall nanotubes.
An L-histidine ester terminated bolaamphiphile (BolaHis) was found to form hydrogels and self-assemble into single-wall nanotubes and single molecular thick fibers triggered by proton and copper ions, respectively. The hydrogels showed good tolerance to a concentrated acid environment and excellent selectivity towards Cu(2+) over other metal ions. PMID:23589838
Liu, Yaqing; Wang, Tianyu; Li, Zhibo; Liu, Minghua
Development of a Versatile Laser Ultrasonic System and Application to On-Line Measurement for Process Control of Wall Thickness and Eccentrictiy of Steel Seamless Mechanical Tubing
Researchers at the Timken Company conceived a project to develop an on-line instrument for wall thickness measurement of steel seamless mechanical tubing based on laser ultrasonic technology. The instrument, which has been installed and tested at a piercing mill, provides data on tube eccentricity and concentricity. Such measurements permit fine-tuning of manufacturing processes to eliminate excess material in the tube wall and therefore provide a more precisely dimensioned product for their customers. The resulting process energy savings are substantial, as is lowered environmental burden. The expected savings are $85.8 million per year in seamless mechanical tube piercing alone. Applied across the industry, this measurement has a potential of reducing energy consumption by 6 x 10{sup 12} BTU per year, greenhouse gas emissions by 0.3 million metric tons carbon equivalent per year, and toxic waste by 0.255 million pounds per year. The principal technical contributors to the project were the Timken Company, Industrial Materials Institute (IMI, a contractor to Timken), and Oak Ridge National Laboratory (ORNL). Timken provided mill access as well as process and metallurgical understanding. Timken researchers had previously developed fundamental ultrasonic analysis methods on which this project is based. IMI developed and fabricated the laser ultrasonic generation and receiver systems. ORNL developed Bayesian and wavelet based real-time signal processing, spread-spectrum wireless communication, and explored feature extraction and pattern recognition methods. The resulting instrument has successfully measured production tubes at one of Timken's piercing mills. This report concentrates on ORNL's contribution through the CRADA mechanism. The three components of ORNL's contribution were met with mixed success. The real-time signal-processing task accomplished its goal of improvement in detecting time of flight information with a minimum of false data. The signal processing algorithm development resulted in a combination of processing steps that can be set to generate no spoofs from noise, while simultaneously missing fewer than 10% of good trials. The algorithm leads to a 95% probability that the estimate of time of flight is good to within 4 time bins or fewer for laser excitations above 30 mJ for the first two echoes of the signal. Receiver Operating Characteristic (ROC) curves for the algorithm indicate that the algorithm is very robust against errors for excitations above at 35 mJ and above, tolerable at 30 mJ and unacceptable below 30 mJ.
Kisner, R.A.; Kercel, S.W.; Damiano, B.; Bingham, P.R.; Gee, T.F.; Tucker, R.W.; Moore, M.R.; Hileman, M.; Emery, M.; Lenarduzzi, R.; Hardy, J.E.; Weaver, K.; Crutcher, R.; Kolarik, R.V., II; Vandervaart, R.H.
The Effects of Neuromuscular Electrical Stimulation Training on Abdominal Strength, Endurance, and Selected Anthropometric Measures
We studied the effects of self-administered neuromuscular electrical stimulation (NMES) on changes in strength, endurance, selected anthropometric measures, and subjectÆs perceived shape and satisfaction of the abdominal wall. Twenty-four adults (experimental group) stimulated their abdominals 5 days per week (20-40 minutes per session) for 8 weeks and refrained from engaging in any additional exercise during the study. A control group (N=16) refrained from exercising the abdominals or engaging in any other exercise training during the study. Subjects were tested at the beginning, mid-point, and end of the study. Isometric strength of the abdominal muscles was tested using a isokinetic dynamometer, endurance was measured using the ACSM curl-up test, abdominal circumference was measured using a steel tape measure, and body shape and satisfaction were assessed via questionnaire. The stimulation group had a 58% increase in abdominal strength, whereas the control group did not change. The stimulation group also had a 100% increase in abdominal endurance versus a 28% increase in the control group. Waist circumference decreased by of 3.5 cm in the stimulation group compared to no significant change in the control group. All 24 subjects in the stimulation group felt that their midsections were more ōtonedö and ōfirmedö and 13/24 (54%) felt that their posture had improved as a result of the stimulation. None of the control group subjects reported changes in these parameters. There were no significant differences in body weight, BMI, or skinfold thickness over the course of the study in either group. NMES, as used in the current study, resulted in significant improvements in the muscular strength and endurance of the abdominal region, as well as subjectÆs perceived shape and satisfaction of the mid-section. Key Points Electrical muscle stimulation (EMS) was effective in increasing muscle strength and endurance All subjects perceived their abdominal muscles to be firmer and more toned as a result of EMS Abdominal and waist girth was also significantly reduced, despite no changes in body weight or subcutaneous fat PMID:24431963
Porcari, John P.; Miller, Jennifer; Cornwell, Kelly; Foster, Carl; Gibson, Mark; McLean, Karen; Kernozek, Tom
Drought-induced increase in water-use efficiency reduces secondary tree growth and tracheid wall thickness in a Mediterranean conifer.
In order to understand the impact of drought and intrinsic water-use efficiency (iWUE) on tree growth, we evaluated the relative importance of direct and indirect effects of water availability on secondary growth and xylem anatomy of Juniperus thurifera, a Mediterranean anisohydric conifer. Dendrochronological techniques, quantitative xylem anatomy, and (13)C/(12)C isotopic ratio were combined to develop standardized chronologies for iWUE, BAI (basal area increment), and anatomical variables on a 40-year-long annually resolved series for 20 trees. We tested the relationship between iWUE and secondary growth at short-term (annual) and long-term (decadal) temporal scales to evaluate whether gains in iWUE may lead to increases in secondary growth. We obtained a positive long-term correlation between iWUE and BAI, simultaneously with a negative short-term correlation between them. Furthermore, BAI and iWUE were correlated with anatomical traits related to carbon sink or storage (tracheid wall thickness and ray parenchyma amount), but no significant correlation with conductive traits (tracheid lumen) was found. Water availability during the growing season significantly modulated tree growth at the xylem level, where growth rates and wood anatomical traits were affected by June precipitation. Our results are consistent with a drought-induced limitation of tree growth response to rising CO2, despite the trend of rising iWUE being maintained. We also remark the usefulness of exploring this relationship at different temporal scales to fully understand the actual links between iWUE and secondary growth dynamics. PMID:24958369
Olano, Josķ Miguel; Linares, Juan Carlos; GarcĒa-Cervig¾n, Ana I; Arzac, Alberto; Delgado, Antonio; Rozas, Vicente
Pulse Wave Imaging in Murine Abdominal Aortas A Feasibility Study
of mechanical properties of the aortic wall. Keywords; abdominal aortic aneurysm (AAA), high, New York, USA firstname.lastname@example.com Abstract--One of the most crucial aspects of abdominal aortic,2,3]. In aortic aneurysm cases, disruption of the medial elastic fibers may produce aortic stiffening, which
Konofagou, Elisa E.
Polypropylene mesh closure of the complicated abdominal wound
Background: Closure of the abdominal wall in the face of fascial necrosis or massive intestinal edema remains a difficult problem with frequent complications. Prior studies have addressed both the utility and the pitfalls of placing polypropylene mesh in this setting.Methods: We performed a retrospective evaluation of our experience with polypropylene mesh in traumatic and nontraumatic difficult abdominal closures. Timing of
Richard F. Fansler; Paul Taheri; Carey Cullinane; Braulio Sabates; Lewis M. Flint
An Experimental and Numerical Comparison of the Rupture Locations of an Abdominal Aortic Aneurysm
Purpose: To identify the rupture locations of idealized physical models of abdominal aortic aneurysm (AAA) using an in-vitro setup and to compare the findings to those predicted numerically. Methods: Five idealized AAAs were manufactured using Sylgard 184 silicone rubber, which had been mechanically characterized from tensile tests, tear tests, and finite element analysis. The models were then inflated to the point of rupture and recorded using a high-speed camera. Numerical modeling attempted to confirm these rupture locations. Regional variations in wall thickness of the silicone models was also quantified and applied to numerical models. Results: Four of the 5 models tested ruptured at inflection points in the proximal and distal regions of the aneurysm sac and not at regions of maximum diameter. These findings agree with high stress regions computed numerically. Wall stress appears to be independent of wall thickness, with high stress occurring at regions of inflection regardless of wall thickness variations. Conclusion: According to these experimental and numerical findings, AAAs experience higher stresses at regions of inflection compared to regions of maximum diameter. Ruptures of the idealized silicone models occurred predominantly at the inflection points, as numerically predicted. Regions of inflection can be easily identified from basic 3-dimensional reconstruction; as ruptures appear to occur at inflection points, these findings may provide a useful insight into the clinical significance of inflection regions. This approach will be applied to patient-specific models in a future study. PMID:19642790
Doyle, Barry J.; Corbett, Timothy J.; Callanan, Anthony; Walsh, Michael T.; Vorp, David A.; McGloughlin, Timothy M.
Abdominal cocoon or sclerosing peritonitis refers to a rare cause of intestinal obstruction due to formation of a membrane encasing the bowel. We report a case of abdominal cocoon post blunt trauma abdomen. The patient presented with a history of subacute intestinal obstruction and a mobile abdomen lump. Abdominal cocoon was diagnosed on computed tomography. He underwent adhesiolysis with excision of membrane. PMID:25590647
Kaur, Supreet; Doley, Rudra Prasad; Chabbhra, Mohinish; Kapoor, Rajeev; Wig, Jaidev
Effect of the Body Wall on Lithotripter Shock Waves
Abstract Purpose: Determine the influence of passage through the body wall on the properties of lithotripter shock waves (SWs) and the characteristics of the acoustic field of an electromagnetic lithotripter. Methods: Full-thickness ex vivo segments of pig abdominal wall were secured against the acoustic window of a test tank coupled to the lithotripter. A fiber-optic probe hydrophone was used to measure SW pressures, determine shock rise time, and map the acoustic field in the focal plane. Results: Peak positive pressure on axis was attenuated roughly proportional to tissue thicknessŚapproximately 6% per cm. Irregularities in the tissue path affected the symmetry of SW focusing, shifting the maximum peak positive pressure laterally by as much as ?2?mm. Within the time resolution of the hydrophone (7¢15 ns), shock rise time was unchanged, measuring ?17¢21 ns with and without tissue present. Mapping of the field showed no effect of the body wall on focal width, regardless of thickness of the body wall. Conclusions: Passage through the body wall has minimal effect on the characteristics of lithotripter SWs. Other than reducing pulse amplitude and having the potential to affect the symmetry of the focused wave, the body wall has little influence on the acoustic field. These findings help to validate laboratory assessment of lithotripter acoustic field and suggest that the properties of SWs in the body are much the same as have been measured in vitro. PMID:24308532
McAteer, James A.; Williams, James C.; Berwick, Zachary C.
Abdominal Wall Reconstruction in a Trauma Setting
According to the World Health Organization ōGlobal burden of disease studyö, future demographics of trauma are expected to\\u000a show an increase in morbidity and mortality. In the past few decades, the field of trauma surgery has evolved to provide global\\u000a and comprehensive care of the injured. While the modern day trauma surgeon is well trained to deal with multitrauma patients
Sathnur B. Pushpakumar; Brandon J. Wilhelmi; Vera C. van-Aalst; Joseph C. Banis Jr; John H. Barker
Lethal complication after abdominal wall reduction.
Obesity is a growing medical problem in Europe and the USA. Plastic surgery is increasing in popularity as a treatment option for correcting skin surplus after dieting. This is often done in private clinics, and is not without risk. In this case, the early symptoms of disproportionate pain and swelling were not followed by immediate inspection in a hospital. The patient died within 48 hours due to clostridium infection. We advocate a 24/7 postoperative care facility, and recommend a sequence of diagnostic and therapeutic measures. PMID:18555001
van Samkar, G; van der Hoeven, J; Hollmann, M W; Goslings, J C
Genetics Home Reference: Abdominal wall defect
... problems in infancy experience recurrent lung infections or asthma later in life. Affected infants often have gastrointestinal problems including a backflow of stomach acids into the esophagus ( ...
Advancements in identifying biomechanical determinants for abdominal aortic aneurysm rupture.
Abdominal aortic aneurysms are a common health problem and currently the need for surgical intervention is determined based on maximum diameter and growth rate criteria. Since these universal variables often fail to predict accurately every abdominal aortic aneurysms evolution, there is a considerable effort in the literature for other markers to be identified towards individualized rupture risk estimations and growth rate predictions. To this effort, biomechanical tools have been extensively used since abdominal aortic aneurysm rupture is in fact a material failure of the diseased arterial wall to compensate the stress acting on it. The peak wall stress, the role of the unique geometry of every individual abdominal aortic aneurysm as well as the mechanical properties and the local strength of the degenerated aneurysmal wall, all confer to rupture risk. In this review article, the assessment of these variables through mechanical testing, advanced imaging and computational modeling is reviewed and the clinical perspective is discussed. PMID:24757027
Kontopodis, Nikolaos; Metaxa, Eleni; Papaharilaou, Yannis; Tavlas, Emmanouil; Tsetis, Dimitrios; Ioannou, Christos
Abdominal Decompression in Children
Abdominal compartment syndrome (ACS) increases the risk for mortality in critically ill children. It occurs in association with a wide variety of medical and surgical diagnoses. Management of ACS involves recognizing the development of intra-abdominal hypertension (IAH) by intra-abdominal pressure (IAP) monitoring, treating the underlying cause, and preventing progression to ACS by lowering IAP. When ACS is already present, supporting dysfunctional organs and decreasing IAP to prevent new organ involvement become an additional focus of therapy. Medical management strategies to achieve these goals should be employed but when medical management fails, timely abdominal decompression is essential to reduce the risk of mortality. A literature review was performed to understand the role and outcomes of abdominal decompression among children with ACS. Abdominal decompression appears to have a positive effect on patient survival. However, prospective randomized studies are needed to fully understand the indications and impact of these therapies on survival in children. PMID:22482041
Ejike, J. Chiaka; Mathur, Mudit
Thickness of the pinned layer as a controlling factor in domain wall formation during training in IrMn-based spin valves
Studies of CoFe-based spin valves with antiferromagnetic IrMn layers as thin as 1.6 nm have demonstrated that a domain wall parallel to the surface develops in the pinned layer after training at the magnetoresistance (MR) maximum. To investigate the effects of domain wall formation on the MR, we have studied the depth profile of the vector magnetization in comparable spin
Jun Park; Shannon M. Watson; C. M. Furjanic; D. K. Draganova; S. D. Eisenberg; D. J. Tighe; P. A. Kienzle; M. J. Carey; J. A. Borchers; P. D. Sparks; J. C. Eckert
[Thoracic and abdominal wounds].
Thoracic and abdominal wounds are characterized by their diversity, their possible danger and the necessity of a successful diagnosis and therapy strategy. Management of thoracic wounds and indications of surgical treatment are conditioned by airway and hemodynamic states, paraclinical exams and chest drainage. The approach of abdominal wounds is based upon their possible penetrating character. Surgical indications, even if very discussed, are still wider. Thoraco-abdominal wounds could concern the diaphragm and are remarkable for their surgical strategy. PMID:9208685
Martinod, E; Lang-Lazdunski, L; Liard, O; Jancovici, R
CT diagnosis of ruptured abdominal aortic aneurysm
Abdominal computed tomography was performed in six patients with suspected ruptured abdominal aortic aneurysm but in whom an alternate clinical diagnosis was seriously considered. In each patient, a large aortic aneurysm was demonstrated in association with a retroperitoneal accumulation of high-density blood. The retroperitoneal blood was primarily confined to the extracapsular perinephric space. In four of the six patients, a focal area of the aortic wall was indistinct on the side of the retroperitoneal hemorrhage at the presumed site of rupture. Five of the six patients underwent emergency surgery, which confirmed the site of aneurysm, presence of rupture and the location of fresh retroperitoneal blood.
Rosen, A.; Korobkin, M.; Silverman, P.M.; Moore, A.V. Jr.; Dunnick, N.R.
Abdominal Aortic Aneurysms: Treatments
... renal disease Infertility Liver disease Needle biopsy Osteoporosis Pediatrics Pelvic pain ... Aortic Aneurysms Interventional Radiologists Treat Abdominal Aneurysms Nonsurgically Interventional radiologists ...
[Treatment of thoracic and abdominal cavity perforation complicated by Henoch-Schonlein purpura nephritis in a patient with high-voltage electric burn].
A 55-year-old male patient suffered from severe high-voltage electric burn with an area of 20%TBSA full-thickness injury. The injury involved the distal end of left upper limb, right trunk, and whole abdominal wall. Fracture of the 7th-10th ribs was found in the right side of chest, with perforation of abdominal cavity, and bilateral pleural effusion was found. Part of the small intestine was necrotic and exposed. At the early stage, xeno-acellular dermal matrix was grafted after debridement of abdominal wound; peritoneal lavage was performed; negative pressure drainage was performed in orificium fistula of intestine for promoting the adhesion between perforated intestine and abdominal scar. Two orificium fistulas formed after closure of abdominal granulation wound by autologous skin grafting. Eschar of chest wall and denatured ribs were retained. The risk of infection of thoracic cavity was decreased by promoting the adhesion between lung tissue and chest wall. During the treatment, the patient was diagnosed with Henoch-Schonlein purpura nephritis by renal biopsy, with the symptoms of purpura in the lower limbs, heavy proteinuria, severe hypoalbuminemia, edema, etc. After control of kidney damage by immunosuppressive treatment instead of glucocorticoid, alleviation of the levels of proteinuria and blood albumin, free latissimus dorsi myocutaneous flap was excised to repair chest wall, and free skin graft was excised to repair intestinal fistula. After all the wounds were successfully covered, the patient was treated with glucocorticoid combined with immunosuppressants for more than 1 year. The patient was followed up for 3 years, and his renal function was completely recovered with satisfactory clinical outcome. PMID:24360004
Zhang, Wei; Xie, Wei-guo; Min, Wei-xiong; Wang, De-yun; Zhang, Jia; Wan, Shi-yong
Axial prestretch and circumferential distensibility in biomechanics of abdominal aorta.
Elastic arteries are significantly prestretched in an axial direction. This property minimises axial deformations during pressure cycle. Ageing-induced changes in arterial biomechanics, among others, are manifested via a marked decrease in the prestretch. Although this fact is well known, little attention has been paid to the effect of decreased prestretch on mechanical response. Our study presents the results of an analytical simulation of the inflation-extension behaviour of the human abdominal aorta treated as nonlinear, anisotropic, prestrained thin-walled as well as thick-walled tube with closed ends. The constitutive parameters and geometries for 17 aortas adopted from the literature were supplemented with initial axial prestretches obtained from the statistics of 365 autopsy measurements. For each aorta, the inflation-extension response was calculated three times, with the expected value of the initial prestretch and with the upper and lower confidence limit of the initial prestretch derived from the statistics. This approach enabled age-related trends to be evaluated bearing in mind the uncertainty in the prestretch. Despite significantly decreased longitudinal prestretch with age, the biomechanical response of human abdominal aorta changes substantially depending on the initial axial stretch was used. In particular, substituting the upper limit of initial prestretch gave mechanical responses which can be characterised by (1) low variation in axial stretch and (2) high circumferential distensibility during pressurisation, in contrast to the responses obtained for their weakly prestretched counterparts. The simulation also suggested the significant effect of the axial prestretch on the variation of axial stress in the pressure cycle. Finally, the obtained results are in accordance with the hypothesis that circumferential-to-axial stiffness ratio is the quantity relatively constant within this cycle. PMID:24136338
Horn², LukßÜ; NetuÜil, Marek; Vo?avkovß, Tereza
Ameliorative role of gemfibrozil against partial abdominal aortic constriction-induced cardiac hypertrophy in rats.
Fibrates are peroxisome proliferator-activated receptor-? agonists and are clinically used for treatment of dyslipidemia and hypertriglyceridemia. Fenofibrate is reported as a cardioprotective agent in various models of cardiac dysfunction; however, limited literature is available regarding the role of gemfibrozil as a possible cardioprotective agent, especially in a non-obese model of cardiac remodelling. The present study investigated the role of gemfibrozil against partial abdominal aortic constriction-induced cardiac hypertrophy in rats. Cardiac hypertrophy was induced by partial abdominal aortic constriction in rats and they survived for 4 weeks. The cardiac hypertrophy was assessed by measuring left ventricular weight to body weight ratio, left ventricular wall thickness, and protein and collagen content. The oxidative stress in the cardiac tissues was assessed by measuring thiobarbituric acid-reactive substances, superoxide anion generation, and reduced glutathione level. The haematoxylin-eosin and picrosirius red staining was used to observe cardiomyocyte diameter and collagen deposition, respectively. Moreover, serum levels of cholesterol, high-density lipoproteins, triglycerides, and glucose were also measured. Gemfibrozil (30 mg/kg, p.o.) was administered since the first day of partial abdominal aortic constriction and continued for 4 weeks. The partial abdominal aortic constriction-induced cardiac oxidative stress and hypertrophy are indicated by significant change in various parameters used in the present study that were ameliorated with gemfibrozil treatment in rats. No significant change in serum parameters was observed between various groups used in the present study. It is concluded that gemfibrozil ameliorates partial abdominal aortic constriction-induced cardiac oxidative stress and hypertrophy and in rats. PMID:24905340
Singh, Amrit Pal; Singh, Randhir; Krishan, Pawan
Effect of open-label infusion of an apoA-I-containing particle (CER-001) on RCT and artery wall thickness in patients with FHA.
Reverse cholesterol transport (RCT) contributes to the anti-atherogenic effects of HDL. Patients with the orphan disease, familial hypoalphalipoproteinemia (FHA), are characterized by decreased tissue cholesterol removal and an increased atherogenic burden. We performed an open-label uncontrolled proof-of-concept study to evaluate the effect of infusions with a human apoA-I-containing HDL-mimetic particle (CER-001) on RCT and the arterial vessel wall in FHA. Subjects received 20 infusions of CER-001 (8 mg/kg) during 6 months. Efficacy was assessed by measuring (apo)lipoproteins, plasma-mediated cellular cholesterol efflux, fecal sterol excretion (FSE), and carotid artery wall dimension by MRI and artery wall inflammation by (18)F-fluorodeoxyglucose-positron emission tomography/computed tomography scans. We included seven FHA patients: HDL-cholesterol (HDL-c), 13.8 [1.8-29.1] mg/dl; apoA-I, 28.7 [7.9-59.1] mg/dl. Following nine infusions in 1 month, apoA-I and HDL-c increased directly after infusion by 27.0 and 16.1 mg/dl (P = 0.018). CER-001 induced a 44% relative increase (P = 0.018) in in vitro cellular cholesterol efflux with a trend toward increased FSE (P = 0.068). After nine infusions of CER-001, carotid mean vessel wall area decreased compared with baseline from 25.0 to 22.8 mm(2) (P = 0.043) and target-to-background ratio from 2.04 to 1.81 (P = 0.046). In FHA-subjects, CER-001 stimulates cholesterol mobilization and reduces artery wall dimension and inflammation, supporting further evaluation of CER-001 in FHA patients. PMID:25561459
Kootte, Ruud S; Smits, Loek P; van der Valk, Fleur M; Dasseux, Jean-Louis; Keyserling, Constance H; Barbaras, Ronald; Paolini, John F; Santos, Raul D; van Dijk, Theo H; Dallinga-van Thie, Geesje M; Nederveen, Aart J; Mulder, Willem J M; Hovingh, G Kees; Kastelein, John J P; Groen, Albert K; Stroes, Erik S
Association of Coronary Heart Disease Incidence with Carotid Arterial Wall Thickness and Major Risk Factors: The Atherosclerosis Risk in Communities (ARIC) Study, 1987-1993
Few studies have determined whether greater carotid artery intima-media thickness (IMT) in asymptomatic individuals is associated prospectively with increased risk of coronary heart disease (CHD). In the Atheroscle- rosis Risk in Communities Study, carotid IMT, an index of generalized atherosclerosis, was defined as the mean of IMT measurements at six sites of the carotid arteries using B-mode ultrasound. The authors
Lloyd E. Chambless; Gerardo Heiss; Aaron R. Folsom; Wayne Rosamond; Moyses Szklo; A. Richey Sharrett; Limin X. Clegg
Gradient Echo MRI Characterization of Development of Atherosclerosis in the Abdominal Aorta in Watanabe Heritable Hyperlipidemic Rabbits
Purpose. The Watanabe Heritable Hyperlipidemic (WHHL) rabbit provides an important model of spontaneous atherosclerosis. With a strain of WHHL rabbits which do not develop abdominal aorta lumen stenosis even with advanced atherosclerosis, we studied the MRI-histology correlation, and the natural progression of atherosclerosis in the abdominal aorta. In addition, intra-reader segmentation repeatability and scan-rescan reproducibility were assessed. Methods. Two batches of female WHHL rabbits were used. The first batch of 6 rabbits was scanned at 20 weeks old. A second batch of 17 rabbits was scanned at 50 weeks old and then randomly divided into two subgroups: 8 were killed for histologic investigation; 9 were kept alive for follow-up, with repeat scanning a week later to assess scan-rescan reproducibility, and again at 73 weeks old to assess disease progression. MR images were acquired at 4.7 T using a chemical shift selective fat suppression gradient echo with a saturation band suppressing blood signal within the aortic lumen. Five slices per animal were acquired, centered around the renal artery region of the abdominal aorta, with in-plane resolution of 0.195 mm and slice thickness of 3 mm. Results. The coefficient of variation for intra-reader reproducibility for aortic wall thickness measurements was 2.5% for repeat segmentations of the same scans on the same day, but segmentations of these same scans made 8 months later showed a systematic change, suggesting that intra-reader bias as well as increased variability could compromise assessments made over time. Comparative analyses were therefore performed in one postprocessing session. The coefficient of variation for scan-rescan reproducibility for aortic wall thickness was 5.5% for nine pairs of scans acquired a week apart and segmented on the same day. Good MRI-histology correlation was obtained. The MRI-measured mean aortic wall thickness of animals at 20 weeks of age was 76% that of animals at 50 weeks of age (p < 0.001). There was a small increase in aortic wall thickness between 50 and 73 weeks of age, but this was not significant (p > 0.05). The corresponding differences in lumen cross-sectional areas at 20, 50, and 73 weeks of age were not significant. These results were consistent with in-house historical histology data on this strain of rabbits. Conclusions. High-resolution gradient echo MRI can follow disease progression in the WHHL rabbit spontaneous atherosclerosis disease model.
Wang, Yi-Xiang J., E-mail: firstname.lastname@example.com; Kuribayashi, Hideto [AstraZeneca (United Kingdom); Wagberg, Maria [AstraZeneca (Sweden); Holmes, Andrew P.; Tessier, Jean J.; Waterton, John C. [AstraZeneca (United Kingdom)
A report is made on the demonstration of a first-generation Wall Surveyor that is capable of surveying the interior and thickness of a stone, brick, or cement wall. LLNL`s Micropower Impulse Radar is used, based on emitting and detecting very low amplitude and short microwave impulses (MIR rangefinder). Six test walls were used. While the demonstrator MIR Wall Surveyor is not fieldable yet, it has successfully scanned the test walls and produced real-time images identifying the walls. It is planned to optimize and package the evaluation wall surveyor into a hand held unit.
Mullenhoff, D.J.; Johnston, B.C.; Azevedo, S.G.
[Ultrasound for abdominal lymphadenopathy].
This CME-review is about the clinical importance of the abdominal lymph node diagnostic with special attention to various ultrasound techniques. This includes innovative techniques like contrast enhanced ultrasound and elastography. The clinical importance of ultrasound in relation to cross sectional imaging will be the target of the article as well as anatomic- topographic aspects. The article deals as well with endosonographic techniques because of the upmost importance of the technique for diagnosing mediastinal and abdominal lymphnode swellings. In conclusion of the article different clinical scenarios and clinical algorithms are presented to help the reader to diagnose abdominal lymphadenopathy correctly in an efficient way. PMID:23633280
Dietrich, C F; Hocke, M; Jenssen, C
Abdominal compartment syndrome
Intra-abdominal hypertension (IAH) associated with organ dysfunction\\u0009\\u0009\\u0009 defines the abdominal compartment syndrome (ACS). Elevated intra-abdominal\\u0009\\u0009\\u0009 pressure (IAP) adversely impacts pulmonary, cardiovascular, renal, splanchnic,\\u0009\\u0009\\u0009 musculoskeletal\\/integumentary, and central nervous system physiology. The\\u0009\\u0009\\u0009 combination of IAH and disordered physiology results in a clinical syndrome\\u0009\\u0009\\u0009 with significant morbidity and mortality. The onset of the ACS requires prompt\\u0009\\u0009\\u0009 recognition and appropriately timed and staged intervention
Jeffrey Bailey; Marc J Shapiro
[What do general, abdominal and vascular surgeons need to know on plastic surgery - aspects of plastic surgery in the field of general, abdominal and vascular surgery].
There is overlap between general, abdominal and vascular surgery on one hand and plastic surgery on the other hand, e.g., in hernia surgery, in particular, recurrent hernia, reconstruction of the abdominal wall or defect closure after abdominal or vascular surgery. Bariatric operations involve both special fields too. Plastic surgeons sometimes use skin and muscle compartments of the abdominal wall for reconstruction at other regions of the body. This article aims to i) give an overview about functional, anatomic and clinical aspects as well as the potential of surgical interventions in plastic surgery. General/abdominal/vascular surgeons can benefit from this in their surgical planning and competent execution of their own surgical interventions with limited morbidity/lethality and an optimal, in particular, functional as well as aesthetic outcome, ii) support the interdisciplinary work of general/abdominal/vascular and plastic surgery, and iii) provide a better understanding of plastic surgery and its profile of surgical interventions and options. PMID:24771218
Damert, H G; Altmann, S; St³bs, P; Infanger, M; Meyer, F
... main blood vessel that supplies blood to the abdomen, pelvis, and legs. An abdominal aortic aneurysm occurs ... dissection). Symptoms of rupture include: Pain in the abdomen or back. The pain may be severe, sudden, ...
Abdominal film; X-ray - abdomen; Flat plate; KUB x-ray ... Diagnose a pain in the abdomen or unexplained nausea Identify suspected problems in the urinary system, such as a kidney stone Identify blockage in the intestine Locate ...
NSDL National Science Digital Library
Set of normal abdominal CT images with various important anatomic structures outlined, for cine viewing to gain a 3D view of the structure and its relationship to adjacent organs.Annotated: trueDisease diagnosis: Normal
Shaffer, Kitt
Abdominal ultrasound is a scanning technique used to image the interior of the abdomen. Like the X-ray, MRI, ... it has its place as a diagnostic tool. Ultrasound scans use high frequency sound waves to produce ...
The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.
Meier, W R
Nonlinear incompressible finite element for simulating loading of cardiac tissue--Part II: Three dimensional formulation for thick ventricular wall segments.
A three dimensional incompressible and geometrically as well as materially nonlinear finite element is formulated for future implementation in models of cardiac mechanics. The stress-strain relations in the finite element are derived from a recently proposed constitutive law which is based on the histological composition of the myocardium. The finite element is formulated for large deformations and considers incompressibility by introducing the hydrostatic pressure as an additional variable. The results of passive loading cases simulated by this element allow to analyze the mechanical properties of ventricular wall segments, the main of which are that the circumferential direction is stiffer than the longitudinal one, that its shear stiffness is considerably lower than its tensile and compressive stiffness and that, due to its mechanically prominent role, the collagenous matrix may affect the myocardial perfusion. PMID:3347025
Horowitz, A; Sheinman, I; Lanir, Y
Measuring Thicknesses of Wastewater Films
NASA Technical Reports Server (NTRS)
Sensor determines when thickness of film of electrically conductive wastewater on rotating evaporator drum exceeds preset value. Sensor simple electrical probe that makes contact with liquid surface. Made of materials resistant to chemicals in liquid. Mounted on shaft in rotating cylinder, liquid-thickness sensor extends toward cylinder wall so tip almost touches. Sensor body accommodates probe measuring temperature of evaporated water in cylinder.
Schubert, F. H.; Davenport, R. J.
Abdominal Compartment Syndrome Secondary to Chronic Constipation
Abdominal compartment syndrome (ACS) is defined as an elevated intraabdominal pressure with evidence of organ dysfunction. The majority of published reports of ACS are in neonates with abdominal wall defects and in adults following trauma or burns, but it is poorly described in children. We describe the unusual presentation of an 11-year-old boy with a long history of chronic constipation who developed acute ACS requiring resuscitative measures and emergent disimpaction. He presented with a 2-week history of increasing abdominal pain, nausea, diminished appetite and longstanding encopresis. On exam, he was emaciated with a massively distended abdomen with a palpable fecaloma. Abdominal XR confirmed these findings. Within 24 hours of presentation, he became tachycardic and oliguric with orthostatic hypotension. Following two enemas, he acutely deteriorated with severe hypotension, marked tachycardia, acute respiratory distress, and a declining mental status. Endotracheal intubation, fluid boluses, and vasopressors were commenced, followed by emergent surgical fecal disimpaction. This resulted in rapid improvement in vital signs. He has been thoroughly investigated and no other condition apart from functional constipation has been identified. Although ACS secondary to constipation is extremely unusual, this case illustrates the need to actively treat constipation and what can happen if it is not. PMID:22606517
Flageole, Helene; Ouahed, Jodie; Walton, J. Mark; Yousef, Yasmin
Measurement of arterial stiffness in subjects with and without renal disease: Are changes in the vessel wall earlier and more sensitive markers of cardiovascular disease than intima media thickness and pulse pressure?
There is increased cardiovascular (CV) mortality in subjects with chronic kidney disease (CKD). Arterial stiffness in these subjects is increased when compared to a healthy population. Markers of arterial stiffness and intima media thickness (IMT) are predictors of CV mortality. The aim of this study was to investigate whether there is any difference in markers of arterial stiffness and IMT between subjects with normal renal function and those with mild renal disease. The arterial distension waveform, IMT, diameter, and brachial blood pressure were measured to calculate Young's modulus (E) and elastic modulus (Ep) in the common carotid arteries of subjects with normal kidney function (estimated glomerular filtration rate [eGFR] >90) and those mild CKD (stage 2, eGFR 89¢60). Data were available for 15 patients with normal kidney function and 29 patients with mild CKD. The subjects with mild CKD were older, but other co-variables were not significantly different. Both arterial wall stiffness parameters (E and Ep), but not IMT were significantly higher in the mild CKD group. Logistic regression demonstrated that only the arterial wall stiffness parameters (Ep and E) were independently associated with mild renal disease compared with normal, in a model adjusting for sex, age and diabetes and history of cardiovascular disease (CVD). E and Ep may be early markers of CVD in subjects with mild CKD that may manifest change before other more recognized markers such as IMT and pulse pressure. PMID:25684868
Claridge, M.; Wilmink, T.; Ferring, M.; Dasgupta, I.
DIEP breast reconstruction following multiple abdominal liposuction procedures
Objective: Previous abdominal wall surgery is viewed as a contraindication to abdominal free tissue transfer. We present two patients who underwent multiple abdominal liposuction procedures, followed by successful free deep inferior epigastric artery perforator flap. We review the literature pertaining to reliability of abdominal free flaps in those with previous abdominal surgery. Methods: Review of case notes and radiological investigations of two patients, and a PubMed search using the terms ōDIEPö, ōdeep inferior epigastricö, ōTRAMö, ōtransverse rectus abdominisö, ōperforatorö and ōlaparotomyö, ōabdominal wallö, ōliposuctionö, ōliposculptureö, ōfat graftö, ōpfannenstielö, with subsequent appraisal of relevant papers by the first and second authors. Results: Patient 1 had 3 episodes of liposuction from the abdomen for fat grafting to a reconstructed breast. Subsequent revision reconstruction of the same breast with DIEP flap was preceded by CT angiography, which demonstrated normal perforator anatomy. The reconstruction healed well with no ischaemic complications. Patient 2 had 5 liposuction procedures from the abdomen to graft fat to a wide local excision defect. Recurrence of cancer led to mastectomy and immediate reconstruction with free DIEP flap. Preoperative MR angiography demonstrated a large perforator right of the umbilicus, with which the intraoperative findings were consistent. The patient had an uneventful recovery and good healing with no fat necrosis or wound dehiscence. Conclusions: We demonstrate that DIEP flaps can safely be raised without perfusion-related complications following multiple liposuction procedures to the abdomen. The safe interval between procedures is difficult to quantify, but we demonstrate successful free flap after 16 months. PMID:25671046
Nicholson, Simon; Kotwal, Ashutosh; Akali, Augustine
[Abdominal bloating: an up-to-date].
Bloating is a common symptom, especially in women. In the clinical practice, it remains a therapeutic challenge. Since recently, its pathophysiology is better understood: an impaired transit of gas (particularly in the small bowel) or a visceral hypersensitivity leading to the induction of an abdominal discomfort despite a normal volume of gas are two of the main causes, far more frequent than an excessive production of gas. Moreover, bloating can be related to abnormal viscera-somatic reflexes promoting both an abdomino-phrenic dyssynergia and the relaxation of the muscles of the abdominal wall. From a therapeutic point of view, the efficacy of the gas absorbants remains to be more documented. Besides the treatment of a constipation and the avoidance of nutrients either highly fermentable or rich in fructose, other therapeutic options include prokinetics and drugs acting on visceral sensitivity. Probiotics are another promising option. In some centers, a non pharmacological therapeutic approach, mainly based on hypnosis, is discussed. PMID:19747789
Ducrottķ, P
Abdominal Aortic Aneurysm (AAA) Screening
... covered? Search Medicare.gov for covered items Abdominal aortic aneurysm screening How often is it covered? Medicare Part B (Medical Insurance) covers a one-time abdominal aortic aneurysm ultrasound. You must get a referral for it ...
Screening for Abdominal Aortic Aneurysm
Understanding Task Force Recommendations Screening for Abdominal Aortic Aneurysm The U.S. Preventive Services Task Force (Task Force) has issued a final recommendation statement on Screening for Abdominal Aortic Aneurysm. This final recommendation ...
Common carotid artery wall thickness and external diameter as predictors of prevalent and incident cardiac events in a large population study
Background Arterial diameters enlarge in response to wall thickening, plaques, and many atherosclerotic risk factors. We hypothesized that right common carotid artery (RCCA) diameter would be independently associated with cardiac disease and improve risk discrimination. Methods In a middle-aged, biracial population (baseline n = 11225), we examined associations between 1 standard deviation increments of baseline RCCA diameter with prevalent myocardial infarction (MI) and incident cardiac events (MI or cardiac death) using logistic regression and Cox proportional hazards models, respectively. Areas under the receiver operator characteristic curve (AUC) were used to estimate model discrimination. Results MI was present in 451 (4%) participants at baseline (1987¢89), and incident cardiac events occurred among 646 (6%) others through 1999. Adjusting for IMT, RCCA diameter was associated with prevalent MI (female OR = 2.0, 95%CI = 1.61¢2.49; male OR = 1.16, 95% CI = 1.04¢1.30) and incident cardiac events (female HR = 1.75, 95% CI = 1.51¢2.02; male HR = 1.27, 95% CI = 1.15¢1.40). Associations were attenuated but persisted after adjustment for risk factors (not including IMT) (prevalent MI: female OR = 1.73, 95% CI = 1.40¢2.14; male OR = 1.14, 95% CI = 1.02¢1.28, and incident cardiac events: female HR = 1.26, 95% CI = 1.08¢1.48; male HR = 1.19, 95% CI = 1.08¢1.32). After additional adjustment for IMT, diameter was associated with incident cardiac events in women (HR = 1.18, 95% CI = 1.00¢1.40) and men (HR = 1.17, 95% CI = 1.06¢1.29), and with prevalent MI only in women (OR = 1.73; 95% CI = 1.37¢2.17). In women, when adjustment was limited, diameter models had larger AUC than other models. Conclusion RCCA diameter is an important correlate of cardiac events, independent of IMT, but adds little to overall risk discrimination after risk factor adjustment. PMID:17349039
Eigenbrodt, Marsha L; Sukhija, Rishi; Rose, Kathryn M; Tracy, Richard E; Couper, David J; Evans, Gregory W; Bursac, Zoran; Mehta, Jawahar L
Laparoscopic total abdominal colectomy
The aim of this study was to prospectively assess the impact of laparoscopy upon the outcome of total abdominal colectomy (TAC). Specifically, patients underwent standard laparotomy with TAC and ileoproctostomy (TAC + IP), TAC and ileoanal reservoir (TAC + IAR), laparoscopically assisted TAC + IP (L-TAC + IP), or laparoscopically assisted TAC + IAR (L-TAC + IAR). Parameters studied included
Steven D. Wexner; Olaf B. Johansen; Juan J. Nogueras; David G. Jagelman
Resolvin D1 and Lipoxin A4 Improve Alveolarization and Normalize Septal Wall Thickness in a Neonatal Murine Model of Hyperoxia-Induced Lung Injury
Background The critical fatty acids Docosahexaenoic Acid (DHA) and Arachidonic Acid (AA) decline in preterm infants within the first postnatal week and are associated with neonatal morbidities, including bronchopulmonary dysplasia (BPD). DHA and AA are precursors to downstream metabolites that terminate the inflammatory response. We hypothesized that treatment with Resolvin D1 and/or Lipoxin A4 would prevent lung injury in a murine model of BPD. Objective To determine the effect of Resolvin D1 and/or Lipoxin A4 on hyperoxia-induced lung injury. Methods C57/BL6 pups were randomized at birth to Room Air, Hyperoxia (>90% oxygen), Hyperoxia + Resolvin D1, Hyperoxia + Lipoxin A4, or Hyperoxia + Resolvin D1/Lipoxin A4. Resolvin D1 and/or Lipoxin A4 (2 ng/g) were given IP on days 0, 3, 6, and 9. On day 10, mice were sacrificed and lungs collected for morphometric analyses including Mean Linear Intercept (MLI), Radial Alveolar Count (RAC), and Septal Thickness (ST); RT-PCR analyses of biomarkers of lung development and inflammation; and ELISA for TGF?1 and TGF?2. Result The increased ST observed with hyperoxia exposure was normalized by both Resolvin D1 and Lipoxin A4; while, hyperoxia-induced alveolar simplification was attenuated by Lipoxin A4. Relative to hyperoxia, Resolvin D1 reduced the gene expression of CXCL2 (2.9 fold), TIMP1 (6.7 fold), and PPAR? (4.8 fold). Treatment with Lipoxin A4 also led to a reduction of CXCL2 (2.4 fold) while selectively increasing TGF?2 (2.1 fold) and Smad3 (1.58 fold). Conclusion The histologic and biochemical changes seen in hyperoxia-induced lung injury in this murine model can be reversed by the addition of DHA and AA fatty acid downstream metabolites that terminate the inflammatory pathways and modulate growth factors. These fatty acids or their metabolites may be novel therapies to prevent or treat lung injury in preterm infants. PMID:24892762
Martin, Camilia R.; Zaman, Munir M.; Gilkey, Calvin; Salguero, Maria V.; Hasturk, Hatice; Kantarci, Alpdogan; Van Dyke, Thomas E.; Freedman, Steven D.
[Application of ultrasound in paediatric abdominal trunk blocks].
Although relatively few studies have compared US guidance with established "blind" techniques, the available evidence suggests that the use of US guidance is a safe and effective way to facilitate correct needle placement and adequate spread of LA for abdominal wall nerve blocks. It improves block effectiveness and safety by reducing LA doses and by detecting anatomic variants or unsuspected pathologies. Different techniques are described and discussed: the transverse abdominal nerve blocks, the paraombilical block, the inguinal field block and the fascia transversalis block. Matched with improving technology, the use of US has significant benefits over conventional techniques to perform classic and new abdominal wall nerve blocks in children. However, more studies are required to evaluate the potential of US to support this finding. PMID:22197343
Ludot, H
Abdominal actinomycosis with multiple myeloma: A case report
Actinomycosis is a chronic suppurative infection, for which immune suppression is a predisposing factor. In unusual cases, this disease may present as an abdominal wall involvement simulating a soft tissue tumor as seen in the present case. The presented patient had no signs of trauma or surgical approach and the pathology was considered to be a primary abdominal wall actinomycosis. Preoperative diagnosis is difficult due to the nonspecific nature of clinical presentation, radiographic and laboratory findings. Surgery combined with antibiotic treatment is a curative approach for this relatively rare infection. Surgeons must be aware of this disease in order to ensure correct diagnosis and to prevent performing any unnecessary procedures. The present study describes a case of abdominal actinomycosis with multiple myeloma, together with a review of important points related to this disease. PMID:25202429
Lymphangiogenesis and Angiogenesis in Abdominal Aortic Aneurysm
The pathogenesis of abdominal aortic aneurysm (AAA) is characterized to be inflammation-associated degeneration of vascular wall. Neovascularization is regularly found in human AAA and considered to play critical roles in the development and rupture of AAA. However, little is known about lymphangiogenesis in AAA. The purpose of this study was to demonstrate both angiogenesis and lymphangiogenesis in AAA. Abdominal aortic tissue was harvested either from autopsy (control group) and during open-repair surgery for AAA (AAA group). Adventitial lymphatic vasa vasorum was observed in both groups, but seemed to be no significant morphological changes in AAA. Immunohistochemical studies identified infiltration of lymphatic vessel endothelial hyaluronan receptor (LYVE) ?1, vascular endothelial growth factor (VEGF)-C, and matrix metalloproteinase (MMP)-9-positive macrophages and podoplanin and Prox-1-positive microvessels in the intima/media in AAA wall, where hypoxia-inducible factors (HIF)-1? was expressed. VEGF-C and MMP-9 were not expressed in macrophages infiltrating in the adventitia. Intraoperative indocyanine green fluorescence lymphography revealed lymph stasis in intima/medial in AAA. Fluorescence microscopy of the collected samples also confirmed the accumulation of lymph in the intima/media but not in adventitia. These results demonstrate that infiltration of macrophages in intima/media is associated with lymphangiogenesis and angiogenesis in AAA. Lymph-drainage appeared to be insufficient in the AAA wall. PMID:24651519
Sano, Masaki; Sasaki, Takeshi; Hirakawa, Satoshi; Sakabe, Junichi; Ogawa, Mikako; Baba, Satoshi; Zaima, Nobuhiro; Tanaka, Hiroki; Inuzuka, Kazunori; Yamamoto, Naoto; Setou, Mitsutoshi; Sato, Kohji; Konno, Hiroyuki; Unno, Naoki
Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.
J.F. Cuttino; D.M. Stefanescu; T.S. Piwonka
... also be seen in individuals with nail fungus (onychomycosis), psoriasis, and hypothyroidism. Those who have problems with the thickness of their toenails should consult a foot and ankle surgeon for proper diagnosis and treatment. and or or and or or, ...
Track 14. Cardiovascular Mechanics 14.1. Aneurysms -Abdominal Aortic Aneurysms and Stent-Grafts $273 AAA have considered the tissue as isotropic. However, recent biaxial tensile
Track 14. Cardiovascular Mechanics 14.1. Aneurysms -Abdominal Aortic Aneurysms and Stent Engineering, University of Arizona, Tucson, AZ, USA The formation of an abdominal aortic aneurysm (AAA) occurs:15-09:30 (P6) Transient blood flow - wall interaction in abdominal aortic aneurysms C.M. Scotti 1, E.A. Finol
Papaharilaou, Yannis
Biomarkers in abdominal imaging
Imaging biomarkers are parameters measurable with imaging methods used to detect, stage or grade disease or assess the response\\u000a to treatment. Compared with biochemical or histological markers, imaging biomarkers have the advantage of remaining non-invasive\\u000a and being spatially and temporally resolved. Imaging biomarkers are used in multiple abdominal diseases, including cancer.\\u000a Anatomical imaging biomarkers such as the RECIST criteria are
Bernard E. Van Beers; Valķrie Vilgrain
Injuries to major abdominal arteries and veins frequently are associated with exsanguinating hemorrhage and visceral ischemia. Expeditious management is the key to survival and good outcome. Knowledge of anatomic relationships between viscera and vessels forms the basis for directed dissection, optimal exposure, and lasting repair of vessels. Although penetrating mechanism of injury remains the most common cause of these injuries, trauma surgeons must be familiar with patterns of blunt trauma-mediated injury to avoid the devastating consequences of delayed management. PMID:8782475
Mullins, R J; Huckfeldt, R; Trunkey, D D
Over the past several years, abdominal single photon emission computed tomography (SPECT) imaging has evolved from a research tool to an important clinical imaging modality that is helpful in the diagnostic assessment of a wide variety of disorders involving the abdominal viscera. Although liver-spleen imaging is the most popular of the abdominal SPECT procedures, blood pool imaging is becoming much more widely utilized for the evaluation of cavernous hemangiomas of the liver as well as other vascular abnormalities in the abdomen. Adjunctive indium leukocyte and gallium SPECT studies are also proving to be of value in the assessment of a variety of infectious and neoplastic diseases. As more experience is acquired in this area, SPECT should become the primary imaging modality for both gallium and indium white blood cells in many institutions. Renal SPECT, on the other hand, has only recently been used as a clinical imaging modality for the assessment of such parameters as renal depth and volume. The exact role of renal SPECT as a clinical tool is, therefore, yet to be determined. 79 references.
Van Heertum, R.L.; Brunetti, J.C.; Yudd, A.P.
Steady flow in abdominal aortic aneurysm models.
Steady flow in abdominal aortic aneurysm models has been examined for four aneurysm sizes over Reynolds numbers from 500 to 2600. The Reynolds number is based on entrance tube diameter, and the inlet condition is fully developed flow. Experimental and numerical methods have been used to determine: (i) the overall features of the flow, (ii) the stresses on the aneurysm walls in laminar flow, and (iii) the onset and characteristics of turbulent flow. The laminar flow field is characterized by a jet of fluid (passing directly through the aneurysm) surrounded by a recirculating vortex. The wall shear stress magnitude in the recirculation zone is about ten times less than in the entrance tube. Both wall shear stress and wall normal stress profiles exhibit large magnitude peaks near the reattachment point at the distal end of the aneurysm. The onset of turbulence in the model is intermittent for 2000 < Re < 2500. The results demonstrate that a slug of turbulence in the entrance tube grows much more rapidly in the aneurysm than in a corresponding length of uniform cross section pipe. When turbulence is present in the aneurysm the recirculation zone breaks down and the wall shear stress returns to a magnitude comparable to that in the entrance tube. PMID:8309237
Budwig, R; Elger, D; Hooper, H; Slippy, J
Thick-walled carbon composite multifunctional structures
NASA Astrophysics Data System (ADS)
Satellite programs are moving in the direction of smaller and lighter structures. Technological advances have permitted more sophisticated equipment to be consolidated into compact spaces. Micro-satellites, between 10 and 100 kg, will incorporate micro-electric devices into the lay-up of the satellite structure. These structures will be designed to carry load, provide thermal control, enhance damping, and include integrated passive electronics. These multifunctional structures offer lighter weight, reduced volume, and a 'smarter' overall package for incorporation of sensors, electronics, fiber optics, powered appendages or active components. McDonnell Douglas Corporation (MDC) has applied technology from the synthesis and processing of intelligent cost effective structures (SPICES) and independent research and development (IRAD) programs to the modular instrument support system (MISS) for multifunctional space structures and micro-satellites. The SPICES program was funded by the Defense Advanced Research Projects Agency (DARPA) to develop affordable manufacturing processes for smart materials to be used in vibration control, and the MISS program was funded by NASA-Langley. The MISS program was conceived to develop concepts and techniques to make connections between different multifunctional structures. MDA fabricated a trapezoidal carbon composite structure out of IM7/977-3 tape prepreg. Flex circuits, thermal and optical conduits were embedded to realize a utility modular connector. These provide electrical, thermal, optical and mechanical connections between micro- satellite components. A quick disconnect mount was also developed to accommodate a variety of devices such as solar arrays, power sources, thermal transfer and vibration control modules.
Haake, John M.; Jacobs, Jack H.; McIlroy, Bruce E.
Intra-abdominal hypertension: pulmonary and cerebral complications.
Intra-abdominal hypertension causes many physiologic changes, primarily by reducing thoracic compliance and secondarily causing organ failure, which is the body's normal response to trauma or acute inflammatory response. Compartment syndrome as a cause of abdominal hypertension has adverse effects on the circulation, threatening the function and viability of tissues. Intra-abdominal hypertension with the clinical picture of compartment syndrome is a reperfusion injury that is a cyclic event. Elevated intra-abdominal pressure due to whatever mechanism affects all intra-abdominal viscera, including the abdominal wall. Due to edema reducing thoracic compliance, producing severe encephalopathy and leading to severe ischemia with generation of significant quantities of reactive oxygen free radicals as well peroxidation products released from the intestine, liver and spleen. Elevated intracranial pressure causes encephalopathy and the risk of neuronal damage due to the sharp decrease in cerebral perfusion pressure. Elevated intracranial pressure is due to restriction of outflow from the lumbar venous plexus. The etiology of the sudden increase in capillary permeability remains unclear. Decompressive laparotomy leads to a rapid improvement in pulmonary parameters and oxygen delivery. The clinical state after decompression is an example of ischemia-reperfusion injury requiring therapy