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Early failures in large head metal-on-metal total hip arthroplasty.
Althuizen, Martje N R; V Hooff, Miranda L; v d Berg-v Erp, Saskia H M; V Limbeek, Jacques; Nijhof, Marc W
Concerns have recently been raised about large head metal-on-metal total hip arthroplasties (LDH THA). Metal ion release due to wear may cause osteolysis, pseudotumours and necrosis. In addition, fixation of certain acetabular components is thought to be suboptimal. We present the short term outcome of the Durom LDH THA. Retrospectively, a consecutive series of 64 implants in 60 patients was analysed with a mean follow-up of 37 months. Clinical and radiological evaluation was performed on a regular basis, followed by additional evaluations when indicated. The 10-year revision percentage was calculated and compared with National Institute for Health and Clinical Excellence (NICE) standards. Six patients (six hips) underwent cup revision (9%). Four of these cups showed no or minimal bone fixation. Three patients had a pseudotumour. In two revision cases, ALVAL (aseptic lymphocyte-dominated vasculitis-associated lesion) was present. Lack of bone ingrowth and the presence of ARMD (adverse reaction to metal debris) seem to contribute to a high failure rate of the Durom LDH THA. The predicted ten-year revision rate of 14.2% (95% CI 5.6-22.8) is, given the broad confidence interval, not significantly outside NICE recommended standards. However, it is not clear which factors, if any, predict implant failure. Therefore, we do not advocate the use of this implant. PMID:23233178
Large-head metal-on-metal total hip arthroplasty using the Durom acetabular component at minimum 1-year interval.
Illgen, Richard L; Heiner, John P; Squire, Matthew W; Conrad, David N
Large-head metal-on-metal total hip arthroplasty represents novel technology, and outcome data are lacking. We prospectively compared the performance of a nonmodular metal-on-metal acetabular component (Durom; Zimmer, Warsaw, IN) with a modular titanium component (Trilogy, Zimmer). All Durom components placed at our institution with minimum 1-year follow up (n = 63) were compared with an age- and sex-matched Trilogy control group (n = 100). Failure defined as revision or persistent moderate/severe groin pain was significantly higher for the Durom (11.1%) compared with the Trilogy group (0%) (P = .002). Although all acetabular components in both groups appeared radiographically stable, no significant bone ingrowth was noted at the time of Durom revisions. We could not identify any patient/surgical-related factors predictive of failure. Further study is needed to determine the scientific basis for these observations. PMID:20570096
A comparison of leg length and femoral offset discrepancies in hip resurfacing, large head metal-on- metal and conventional total hip replacement: a case series
Background A discrepancy in leg length and femoral offset restoration is the leading cause of patient dissatisfaction in hip replacement surgery and has profound implications on patient quality of life. The aim of this study is to compare biomechanical hip reconstruction in hip resurfacing, large-diameter femoral head hip arthroplasty and conventional total hip replacement. Method Sixty patient's post-operative radiographs were reviewed; 20 patients had a hip resurfacing (HR), 20 patients had a Large Head Metal-on-metal (LHM) hip replacement and 20 patients had a conventional small head Total Hip Replacement (THR). The leg length and femoral offset of the operated and unoperated hips were measured and compared. Results Hip resurfacing accurately restored hip biomechanics with no statistical difference in leg length (P = 0.07) or femoral offset (P = 0.95) between the operated and non-operative hips. Overall HR was superior for reducing femoral offset discrepancies where it had the smallest bilateral difference (-0.2%, P = 0.9). The traditional total hip replacement was least effective at restoring the hip anatomy. Conclusion The use of a larger-diameter femoral head in hip resurfacing does not fully account for the superior biomechanical restoration, as LHM did not restore femoral offset as accurately. We conclude that restoration of normal hip biomechanics is best achieved with hip resurfacing. PMID:22206621
The Correlation of Serum Metal Ions with Functional Outcome Scores at Three-to-Six Years following Large Head Metal-on-Metal Hip Arthroplasty
Patange Subbarao, Sheethal Prasad; Malek, Ibrahim A.; Mohanty, Khitish; Thomas, Phillip; John, Alun
Based on success of hip resurfacing, large head Metal on Metal (MoM) hip arthroplasty has gained significant popularity in recent years. There are growing concerns about metal ions related soft tissue abnormalities. The aim of this study was to define a correlation of metal ions with various functional outcome scores following large head MoM hip arthroplasty. Consecutive cohort of 70 patients (76 hips) with large head MoM hip arthroplasty using SL-Plus femoral stem and Cormet acetabular component were prospectively followed up. An independent observer assessed the patients which included serology for metal ion levels and collection of Oxford Hip, Harris hip, WOMAC, SF-36 & modified UCLA scores. Median serum cobalt and chromium levels were 3.10??g/L (0.35¢62.92) and 4.21??g/L (0.73¢69.27) with total of median 7.30??g/L (2.38¢132.19). The median Oxford, Harris, WOMAC, SF-36 and modified UCLA scores were 36 (6¢48), 87 (21¢100), 36 (24¢110), 104 (10¢125), and 3 (1¢9), respectively. Seventeen patients had elevated serum cobalt and chromium levels ?7??g/L. There was no significant correlation between serum metal ion levels with any of these outcome scores. We recommend extreme caution during follow up of these patients with large head MoM arthroplasty. PMID:24959353
Management of failed metal-on-metal total hip arthroplasty
Griffin, Justin W; DÆApuzzo, Michele; Browne, James A
The theoretical advantages of metal-on-metal (MOM) bearing couples in total hip arthroplasty (THA) have been recently balanced by concerns regarding adverse local and systemic effects. Higher than anticipated early revision rates have been reported by several joint registries. Failed MOM hips present with a spectrum of symptoms and findings and traditional methods of failure must be considered in addition to the failure modes that appear to be unique to the MOM bearing couple. Metal hypersensitivity and soft tissue immune reactions remain incompletely understood and require careful ongoing study. The tools available to evaluate MOM THAs and the indications for revision surgery remain to be defined. Outcomes following revision of MOM hips appear to depend on appropriate evaluation, early identification, and appropriate surgical management. PMID:22720266
Modes of failure in metal-on-metal total hip arthroplasty.
Fehring, Keith A; Fehring, Thomas K
Use of large-head metal-on-metal (MoM) bearing surfaces in total hip arthroplasty (THA) has created new and unique modes of failure for this type of articulation. These unique modes are in addition to the traditional modes of failure seen in conventional THA, which include instability, osteolysis, infection, iliopsoas tendinitis, aseptic loosening, and periprosthetic fracture. Ion levels and cross-sectional imaging are helpful when evaluating a MoM patient in the identification of adverse local tissue reactions. Unique modes of failure in MoM THA include tissue necrosis, metallosis-induced osteolysis, skin hypersensitivity reactions, and rarely systemic cobaltism. This article outlines the evaluation and treatment of modes of failure in MoM THA. PMID:25771314
Functional outcome following a large head total hip arthroplasty: A retrospective analysis of mid term results
Agarwala, Sanjay; Mohrir, Ganesh; Moonot, Pradeep
Background: One of the reasons that hip resurfacing and large head metal on metal (MOM) total hip arthroplasty (THA) became popular in Asia was the possible increased range of movement and thereby improved function of the hip joint. Due to concerns of MOM articulation an alternative bearing was sought. Hence, a shift from large head MOM to large head ceramic on ceramic (COC) was made. The aim of this study was to compare the functional outcome including range of motion (ROM) and dislocation rates following large head MOM and large head COC THA. Materials and Methods: Retrospectively, 39 primary THA with large head MOM with a mean age of 56 years (range 36-72 years) and average followup of 54 months (range 38-70 months) were compared with 23 primary THA with large head COC bearing with a mean age of 48 years (range 36-68 years) and an average followup of 18 months (range 12-26 months). Functional outcome was assessed using the Modified Harris Hip Score. Dislocation rate and ROM were compared. Results: Global ROM averaged 248 degrees with MOM group and 252 degrees with the COC group. One patient with metal bearing had dislocation at an average 3 year followup which required revision THA while there were no complications in the COC group. MHHS averaged 89 points in MOM and 94 in COC THR. Conclusion: This study has shown that large head ceramic on ceramic THA is a good alternative to large head metal on metal THA with comparable dislocation rates and range of movements and without complications of metallosis in Asian patients. PMID:25143647
Large-diameter metal-on-metal total hip arthroplasties: a page in orthopedic history?
Singh, Gurpal; Meyer, Heiko; Ruetschi, Marcel; Chamaon, Kathrin; Feuerstein, Bernd; Lohmann, Christoph H
Large-diameter metal-on-metal (MoM) bearings evolved from the success of hip resurfacing. These implants were used in revision surgery in cases with well-fixed acetabular cups but loose or failed femoral stems, to avoid cup revision. Early data showed low rates of dislocation and potentially low wear profiles due to better fluid film lubrication. The risk of impingement was also thought to be low due to the increased head-neck ratio. Subsequently large-diameter MoM heads gained popularity in primary hip replacement. Recent data has emerged on the unacceptably high revision rates among patients with large-diameter MoM total hip arthroplasties (THAs), high blood levels of metal ions, and adverse tissue reactions. The head-neck (cone-taper) modular interface probably represents the weak link in large metal heads that have been used on conventional tapers. Increased torque of the large head, micromotion, and instability at the cone-taper interface, synergistic interactions between corrosion and wear, edge loading, low clearance, and psoas impingement are the likely causes for early failure of these prostheses. PMID:23529961
Mechanical failure of metal-polyethylene sandwich liner in metal-on-metal total hip replacement.
Oshima, Yasushi; Fetto, Joseph F
Metal-on-metal had been proposed as an optimal articulation in THRs, however, many monoblock prostheses have been recalled in the USA because of significant high rates of early failure. Metal-on-metal prostheses had been implanted in our institution, and this is a case history of a single patient, in whom metal-on-metal THRs with different femoral sizes of heads were implanted. A 57-year-old female patient underwent bilateral total hip replacements with metal-on-metal prostheses using metal-polyethylene "sandwich" liners 9 years ago on the right side and 7 years ago on the left side respectively. The only difference in both sides was the femoral head diameter of 28 mm in right and 34 mm in left. Seven years after the left surgery, the acetabular liner was dissociated, however, metallosis was not detected. Although the larger femoral head was thought to increase hip joint stability, it dictated a reduction in polyethylene thickness in this prosthesis design, and it was 4 mm in the left hip. Recently, metal-on-metal articulations are thought not to be optimal for hip joint bearing surface, however, this clinical failure was due to the polyethylene thickness and quality. PMID:25601670
Cementless Metasul metal-on-metal total hip arthroplasties at 13 years.
Randelli, Filippo; Banci, Lorenzo; D'Anna, Alessandro; Visentin, Ornella; Randelli, Gianni
Second-generation metal-on-metal bearings have been used since the late 1980s as alternative bearings to eliminate aseptic loosening due to polyethylene wear. The aim of the present study was to evaluate the long-term results of a series of Metasul (Zimmer GmbH, Winterthur, Switzerland) metal-on-metal total hip arthroplasty (THA). One hundred forty-nine cementless THAs with a 28-mm Metasul articulation were performed in 111 consecutive patients. The results were retrospectively reviewed at 13 years postoperatively. Clinical and radiographic evaluations and implant survivorship were performed. Seven hips (4.7%) were revised. The overall survivorship with revision for any reason as the end point was 0.94. The average Harris hip score was 91.4. Expansive osteolysis was found adjacent to the stem in 4 hips. Metal wear-related aseptic loosening was not the major reason for failure in our Metasul metal-on-metal THAs. Recurrent dislocation was the main reason for revision in our series. PMID:21621954
Complications Related to Metal-on-Metal Articulation in Trapeziometacarpal Joint Total Joint Arthroplasty
Fr°lich, Christina; Hansen, Torben Bµk
Adverse reactions to metal-on-metal (MoM) prostheses are well known from total hip joint resurfacing arthroplasty with elevated serum chrome or cobalt, pain and pseudo tumor formation. It may, however, also be seen after total joint replacement of the trapeziometacarpal joint using MoM articulation, and we present two cases of failure of MoM prostheses due to elevated metal-serum levels in one case and pseudo tumor formation in another case. Furthermore, we suggest a diagnostic algorithm for joint pain after MoM trapeziometacarpal joint replacement based on published experiences from MoM hip prostheses and adverse reactions to metal. PMID:26020592
Complications Related to Metal-on-Metal Articulation in Trapeziometacarpal Joint Total Joint Arthroplasty.
Fr°lich, Christina; Hansen, Torben Bµk
Adverse reactions to metal-on-metal (MoM) prostheses are well known from total hip joint resurfacing arthroplasty with elevated serum chrome or cobalt, pain and pseudo tumor formation. It may, however, also be seen after total joint replacement of the trapeziometacarpal joint using MoM articulation, and we present two cases of failure of MoM prostheses due to elevated metal-serum levels in one case and pseudo tumor formation in another case. Furthermore, we suggest a diagnostic algorithm for joint pain after MoM trapeziometacarpal joint replacement based on published experiences from MoM hip prostheses and adverse reactions to metal. PMID:26020592
Long-duration metal-on-metal total hip arthroplasties with low wear of the articulating surfaces
Thomas P. Schmalzried; Paul C. Peters; Brian T. Maurer; Charles R. Bragdon; William H. Harris
The 20-year performance of metal-on-metal hip articulations has not been reported. Five McKeeŚFarrar total hip prostheses and one Sivash prosthesis were obtained at revision surgery after a mean implantation time of 21.3 years. A radiographic, histologic, implant, and wear analysis was performed on these total hip implants with cobaltŚchrome metal-on-metal articulations. All cases were associated with femoral component loosening, but
Friction in metal-on-metal total disc arthroplasty: effect of ball radius.
Moghadas, Parshia; Mahomed, Aziza; Hukins, David W L; Shepherd, Duncan E T
Total disc arthroplasty (TDA) can be used to replace a degenerated intervertebral disc in the spine. There are different designs of prosthetic discs, but one of the most common is a ball-and-socket combination. Contact between the bearing surfaces can result in high frictional torque, which can then result in wear and implant loosening. This study was designed to determine the effects of ball radius on friction. Generic models of metal-on-metal TDA were manufactured with ball radii of 10, 12, 14 and 16 mm, with a radial clearance of 0.015 mm. A simulator was used to test each sample in flexion-extension, lateral bending and axial rotation at frequencies of 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75 and 2 Hz under loads of 50, 600, 1200 and 2000 N, in new born calf serum. Frictional torque was measured and Stribeck curves were plotted to illustrate the lubrication regime in each case. It was observed that implants with a smaller ball radius showed lower friction and showed boundary and mixed lubrication regimes, whereas implants with larger ball radius showed boundary lubrication only. This study suggests designing metal-on-metal TDAs with ball radius of 10 or 12 mm, in order to reduce wear and implant loosening. PMID:22177670
A finite element method comparison of wear in two metal-on-metal total hip prostheses.
Cosmi, F; Hoglievina, M; Fancellu, G; Martinelli, B
The contact mechanics of two metal-on-metal (MOM) total hip prostheses was studied by means of the finite element method (FEM). The purpose of the work was to compare two total hip replacements (Durom and Metasul) with regard to the amount of wear debris released. Wear on the bearing surfaces was evaluated following Reye hypotheses from the pressure distribution, computed by means of three-dimensional FEM models; an approximate analytical model based on Hertz contact theory has also been developed and discussed. The results show that in the dry friction condition the Durom joint releases almost twice as much wear volume as produced by the Metasul joint. Therefore, while Durom implants can improve hip stability by increasing the prosthetic impingement-free range of motion (PIF-ROM), Metasul prostheses can be a valuable solution whenever wear represents a critical choice factor. PMID:17236520
Corrosion on the acetabular liner taper from retrieved modular metal-on-metal total hip replacements.
Gascoyne, Trevor C; Dyrkacz, Richard M; Turgeon, Thomas R; Burnell, Colin D; Wyss, Urs P; Brandt, Jan-M
Eight retrieved metal-on-metal total hip replacements displayed corrosion damage along the cobalt-chromium alloy liner taper junction with the Ti alloy acetabular shell. Scanning electron microscopy indicated the primary mechanism of corrosion to be grain boundary and associated crevice corrosion, which was likely accelerated through mechanical micromotion and galvanic corrosion resulting from dissimilar alloys. Coordinate measurements revealed up to 4.3mm(3) of the cobalt-chromium alloy taper surface was removed due to corrosion, which is comparable to previous reports of corrosion damage on head-neck tapers. The acetabular liner-shell taper appears to be an additional source of metal corrosion products in modular total hip replacements. Patients with these prostheses should be closely monitored for signs of adverse reaction towards corrosion by-products. PMID:24997654
Metal on metal hip resurfacing versus uncemented custom total hip replacement - early results
Introduction There is no current consensus on the most appropriate prosthesis for treating symptomatic osteoarthritis (OA) of the hip in young, active patients. Modern metal on metal hip resurfacing arthroplasty (HR) has gained popularity as it is theoretically more stable, bone conserving and easier to revise than total hip arthroplasty. Early results of metal on metal resurfacing have been encouraging. We have compared two well matched cohorts of patients with regard to function, pain relief and patient satisfaction. Methods This prospective study compares 2 cohorts of young, active patients treated with hip resurfacing (137 patients, 141 hips) and custom uncemented (CADCAM) stems (134 patients, 141 hips). All procedures were performed by a single surgeon. Outcome measures included Oxford, WOMAC and Harris hip scores as well as an activity score. Statistical analysis was performed using the unpaired student's t-test. Results One hundred and thirty four and 137 patients were included in the hip replacement and resurfacing groups respectively. The mean age of these patients was 54.6 years. The mean duration of follow up for the hip resurfacing group was 19.2 months compared to 13.4 months for the total hip replacement group. Pre operative oxford, Harris and WOMAC scores in the THA group were 41.1, 46.4 and 50.9 respectively while the post operative scores were 14.8, 95.8 and 5.0. In the HR group, pre- operative scores were 37.0, 54.1 and 45.9 respectively compared to 15.0, 96.8 and 6.1 post operatively. The degree of improvement was similar in both groups. Conclusion There was no significant clinical difference between the patients treated with hip resurfacing and total hip arthroplasty in the short term. PMID:20167056
Intraoperative frozen section analysis for failed metal-on-metal total hip arthroplasty: is it useful?
MacLean, Ian S; Novicoff, Wendy M; Browne, James A
Recent failure mechanisms seen with metal-on-metal (MOM) total hip arthroplasty (THA) include a spectrum of inflammatory and immune-mediated reactions of lymphocyte predominance. Frozen section (FS) analysis has been used to evaluate joints for acute inflammation indicative of infection. However, the impact of the inflammatory response to metal debris on FS analysis is unknown and the usefulness of FS analysis in failed MOM THA has not been reported. This study investigated the impact of intraoperative FS analysis in evaluating the possibility of infection in 30 patients undergoing revision of a failed MOM THA. The authors' experience suggests that FS has acceptable specificity (96.6%) for infection in revision MOM surgery, although one false positive was noted in this series and the addition of FS did not provide obvious diagnostic utility. The authors believe that FS should be used selectively (if at all) in conjunction with other studies to avoid misdiagnosis in failed MOM THA. PMID:25830264
Metal on metal total hip arthroplasty and a large groin mass: Not always adverse reaction to metallic debris.
Krishnan, Harry; Magnussen, Alex; Sharma, Aadhar; Skinner, John
Due to their improved wear rates, Metal-on-metal bearings have been increasingly used in the past decade by orthopaedic surgeons carrying out total hip arthroplasty. However there is increasing evidence that there are significant complications associated with such implants. One well documented complication is that of metallic debris leading to pseudotumour formation, however there is less known about associations with other tumours within the pelvis. We present two cases where an intra-pelvic mass in patients with metal-on-metal implants were diagnosed as being of a different aetiology. This highlights the need for careful assessment of such patients in order to guide appropriate management. PMID:25560054
Large diameter metal on metal total hip replacement for femoral neck fractures with neurological conditions
Li, Jia; Zheng, Wei; Zhao, Jinzhu; Liu, Denghui; Xu, Weidong
Background: Patients with Parkinson's disease and poliomyelitis can have a femoral neck fracture; yet, the optimal methods of treatment for these hips remains controversial. Many constrained or semi-constrained prostheses, using constrained liners (CLs) with a locking mechanism to capture the femoral head, were used to treat femoral neck fractures in patients with neurological disorders. We retrospectively studied a group of patients with Parkinson's disease and poliomyelitis who sustained femoral neck fractures and were treated by total hip arthroplasty using an L-MoM prosthesis. Materials and Methods: We retrospectively reviewed 12 hips in 12 patients who underwent large-diameter metal-on-metal (L-MoM) total hip replacement between May 2007 and October 2009. Eight of the 12 patients (8 hips; 66.7%) had Parkinson's disease and 4 patients (4 hips; 33.3%) were affected with poliomyelitis. Results: The followup time was 5.2 years (range 3.6-6.0 years). At the latest followup, all the patients showed satisfactory clinical and radiographic results, with pain relief. No complications, such as dislocation or aseptic loosening occurred. Conclusion: We believe the use of L-MoM can diminish the rate of instability or dislocation, after operation. The L-MoM is an option for patients with Parkinson's disease and poliomyelitis with femoral neck fracture. PMID:25404774
Poor short term outcome with a metal-on-metal total hip arthroplasty.
Levy, Yadin D; Ezzet, Kace A
Metal-on-metal (MoM) bearings for total hip arthroplasty (THA) have come under scrutiny with reports of high failure rates. Clinical outcome studies with several commercially available MoM THA bearings remain unreported. We evaluated 78 consecutive MoM THAs from a single manufacturer in 68 patients. Sixty-six received cobalt-chrome (CoCr) monoblock and 12 received modular titanium acetabular cups with internal CoCr liners. Femoral components were titanium with modular necks. At average 2.1 years postoperatively, 12 THAs (15.4%) demonstrated aseptic failure (10 revisions, 2 revision recommended). All revised hips demonstrated capsular necrosis with positive histology reaction for aseptic lymphocytic vasculitis-associated lesions/adverse local tissue reactions. Prosthetic instability following revision surgery was relatively common. Female gender was a strong risk factor for failure, though smaller cups were not. Both monoblock and modular components fared poorly. Corrosion was frequently observed around the proximal and distal end of the modular femoral necks. PMID:23538122
Acute delayed infection: increased risk in failed metal on metal total hip arthroplasty.
Prieto, Hernan A; Berbari, Elie F; Sierra, Rafael J
Adverse local tissue reactions occurring in metal-on-metal total hip arthroplasty (MoM THA) could potentially lead to secondary failure modes such as dislocation or infection. The authors report a series of 124 patients treated with MoM hip arthroplasty between 2006 and 2010 with a minimum follow-up of 3 years. Eight hips presented with acute delayed or late periprosthetic joint infection (PJI) (defined as an infection occurring after 3 months in an otherwise well functioning implant). The rate of infection observed was higher than expected, almost 4 times higher (5.6%) compared to previous historical cohorts from our institution (1.3%). This high risk of infection in patients with DePuy ASR implants requires further study but we theorize that the increased prevalence of infection could be due to a combination of particulate debris, molecular (rather than particulate) effects of Co and Cr ions on soft tissues, and/or products of corrosion that may change the local environment predisposing to infection. PMID:24851788
Modern metal-on-metal hip implants.
Bozic, Kevin J; Browne, James; Dangles, Chris J; Manner, Paul A; Yates, Adolph J; Weber, Kristy L; Boyer, Kevin M; Zemaitis, Paul; Woznica, Anne; Turkelson, Charles M; Wies, Janet L
This Technology Overview was prepared using systematic review methodology and summarizes the findings of studies published as of July 15, 2011, on modern metal-on-metal hip implants. Analyses conducted on outcomes by two joint registries indicate that patients who receive metal-on-metal total hip arthroplasty (THA) and hip resurfacing are at greater risk for revision than are patients who receive THA using a different bearing surface combination. Data from these registries also indicate that larger femoral head components have higher revision rates and risk of revision and that older age is associated with increased revision risks of large-head metal-on-metal THA. Several studies noted a correlation between suboptimal hip implant positioning and higher wear rates, local metal debris release, and consequent local tissue reactions to metal debris. In addition, several studies reported elevated serum metal ion concentrations in patients with metal-on-metal hip articulations, although the clinical significance of these elevated ion concentrations remains unknown. PMID:22661570
Cup inclination and serum concentration of cobalt and chromium after metal-on-metal total hip arthroplasty
Wolfram Brodner; Alexander Gr³bl; Rafael Jankovsky; Vanee Meisinger; Stephan Lehr; Florian Gottsauner-Wolf
We investigated whether cup inclination influences serum levels of cobalt and chromium after metal-on-metal total hip arthroplasty. Out of a consecutive series, 3 groups of 20 patients each were established according to their cup inclination: greatest inclination (55░¢63░, mean 58░), intermediate inclination (44░¢46░, mean 45░), and smallest inclination (23░¢37░, mean 33░). We did not detect any statistically significant difference of
Increased risk of revision of cementless stemmed total hip arthroplasty with metal-on-metal bearings.
Varnum, Claus; Pedersen, Alma B; Mõkelõ, Keijo; Eskelinen, Antti; Havelin, Leif Ivar; Furnes, Ove; Kõrrholm, Johan; Garellick, G÷ran; Overgaard, S°ren
Background and purpose - Data from the national joint registries in Australia and England and Wales have revealed inferior medium-term survivorship for metal-on-metal (MoM) total hip arthroplasty (THA) than for metal-on-polyethylene (MoP) THA. Based on data from the Nordic Arthroplasty Register Association (NARA), we compared the revision risk of cementless stemmed THA with MoM and MoP bearings and we also compared MoM THA to each other. Patients and methods - We identified 32,678 patients who were operated from 2002 through 2010 with cementless stemmed THA with either MoM bearings (11,567 patients, 35%) or MoP bearings (21,111 patients, 65%). The patients were followed until revision, death, emigration, or the end of the study period (December 31, 2011), and median follow-up was 3.6 (interquartile range (IQR): 2.4-4.8) years for MoM bearings and 3.4 (IQR: 2.0-5.8) years for MoP bearings. Multivariable regression in the presence of competing risk of death was used to assess the relative risk (RR) of revision for any reason (with 95% confidence interval (CI)). Results - The cumulative incidence of revision at 8 years of follow-up was 7.0% (CI: 6.0-8.1) for MoM bearings and 5.1% (CI: 4.7-5.6) for MoP bearings. At 6 years of follow-up, the RR of revision for any reason was 1.5 (CI: 1.3-1.7) for MoM bearings compared to MoP bearings. The RR of revision for any reason was higher for the ASR (adjusted RR = 6.4, CI: 5.0-8.1), the Conserve Plus (adjusted RR = 1.7, CI: 1.1-2.5) and "other" acetabular components (adjusted RR = 2.4, CI: 1.5-3.9) than for MoP THA at 6 years of follow-up. Interpretation - At medium-term follow-up, the survivorship for cementless stemmed MoM THA was inferior to that for MoP THA, and metal-related problems may cause higher revision rates for MoM bearings with longer follow-up. PMID:25715878
Gender is a significant factor for failure of metal-on-metal total hip arthroplasty.
Latteier, Michael J; Berend, Keith R; Lombardi, Adolph V; Ajluni, Andrew F; Seng, Brian E; Adams, Joanne B
Metal-on-metal (MoM) articulations offers low wear, larger head size, and increased stability. Reports of early failure are troubling and include failure of ingrowth and metal articulation problems such as metallosis, hypersensitivity, pseudotumor, and unexplained pain. This study investigates the survivorship of modern MoM articulations by gender. We reviewed 1589 primary MoM THA in 1363 patients, with minimum 2-year follow-up for 1212 hips. Follow-up averaged 60 months. There were 643 female patients and 719 male patients. The incidence of cup revision was significantly higher in women than in men (8.2% vs 2.7%; P = .0000), as was incidence of aseptic loosening (4.3% vs 1.1%; P = .0006), and failure for metal-bearing complications (2.2% vs 0.6%; P = .0126). There appear to be gender factors influencing the success of MoM THA, which may include hormonal, anatomic, or functional differences. PMID:21641761
Revision of Failed Hip Resurfacing and Large Metal-on-Metal Total Hip Arthroplasty Using Dual-Mobility Components.
Snir, Nimrod; Park, Brian K; Garofolo, Garret; Marwin, Scott E
Revision of metal-on-metal (MoM) total hip arthroplasty (THA) or hip resurfacing is associated with high complication rates. The authors propose dual-mobility components as a surgical option and present short- to mid-term results of MoM hips revised with dual-mobility components. Eighteen consecutive hips that underwent revision of MoM THA or hip resurfacing using dual-mobility components were identified. At final follow-up (mean, 17.5 months), the visual analog scale, modified Harris Hip Score, and SF-12 scores had all improved (P<.05, P<.01, and P<.05, respectively). There were no dislocations or other complications. Revision of failed MoM THA or hip resurfacing using a dual-mobility device is an effective strategy. [Orthopedics. 2015; 38(6):369-374.]. PMID:26091212
Disappointing short-term results with the DePuy ASR XL metal-on-metal total hip arthroplasty.
Bernthal, Nicholas M; Celestre, Paul C; Stavrakis, Alexandra I; Ludington, John C; Oakes, Daniel A
Outcomes of ultralarge-diameter femoral heads used in metal-on-metal (MOM) total hip arthroplasty (THA) are relatively unknown. This study reports on early failures of the ASR XL (Depuy, Warsaw, Ind) and assesses whether a correlation with cup positioning exists. A retrospective review of 70 consecutive MOM THAs with ultralarge-diameter femoral head and monoblock acetabular component was conducted. Minimum follow-up was 24 months. Of 70 THAs, 12 (17.1%) required revision within 3 years for pain (7), loosening (3), and squeaking (2). Three additional THAs noted squeaking, 2 noted grinding, and 3 additional hips had persistent pain. In total, 20 (28.6%) of 70 demonstrated implant dysfunction. Acetabular components for all symptomatic hips were in acceptable range of cup abduction and anteversion. The failures noted with this design do not correlate to cup placement. The high rate of implant dysfunction at early follow-up suggests serious concerns with the concept of MOM THA with an ultralarge-diameter femoral head paired with a monoblock acetabular cup. PMID:22000575
Prediction of contact mechanics in metal-on-metal Total Hip Replacement for parametrically comprehensive designs and loads.
Donaldson, Finn E; Nyman, Edward; Coburn, James C
Manufacturers and investigators of Total Hip Replacement (THR) bearings require tools to predict the contact mechanics resulting from diverse design and loading parameters. This study provides contact mechanics solutions for metal-on-metal (MoM) bearings that encompass the current design space and could aid pre-clinical design optimization and evaluation. Stochastic finite element (FE) simulation was used to calculate the head-on-cup contact mechanics for five thousand combinations of design and loading parameters. FE results were used to train a Random Forest (RF) surrogate model to rapidly predict the contact patch dimensions, contact area, pressures and plastic deformations for arbitrary designs and loading. In addition to widely observed polar and edge contact, FE results included ring-polar, asymmetric-polar, and transitional categories which have previously received limited attention. Combinations of design and load parameters associated with each contact category were identified. Polar contact pressures were predicted in the range of 0-200MPa with no permanent deformation. Edge loading (with subluxation) was associated with pressures greater than 500MPa and induced permanent deformation in 83% of cases. Transitional-edge contact (with little subluxation) was associated with intermediate pressures and permanent deformation in most cases, indicating that, even with ideal anatomical alignment, bearings may face extreme wear challenges. Surrogate models were able to accurately predict contact mechanics 18,000 times faster than FE analyses. The developed surrogate models enable rapid prediction of MoM bearing contact mechanics across the most comprehensive range of loading and designs to date, and may be useful to those performing bearing design optimization or evaluation. PMID:25980556
Particle characterisation and cytokine expression in failed small-diameter metal-on-metal total hip arthroplasties.
Singh, G; Nuechtern, J V; Meyer, H; Fiedler, G M; Awiszus, F; Junk-Jantsch, S; Bruegel, M; Pflueger, G; Lohmann, C H
The peri-prosthetic tissue response to wear debris is complex and influenced by various factors including the size, area and number of particles. We hypothesised that the 'biologically active area' of all metal wear particles may predict the type of peri-prosthetic tissue response. Peri-prosthetic tissue was sampled from 21 patients undergoing revision of a small diameter metal-on-metal (MoM) total hip arthroplasty (THA) for aseptic loosening. An enzymatic protocol was used for tissue digestion and scanning electron microscope was used to characterise particles. Equivalent circle diameters and particle areas were calculated. Histomorphometric analyses were performed on all tissue specimens. Aspirates of synovial fluid were collected for analysis of the cytokine profile analysis, and compared with a control group of patients undergoing primary THA (n = 11) and revision of a failed ceramic-on-polyethylene arthroplasty (n = 6). The overall distribution of the size and area of the particles in both lymphocyte and non-lymphocyte-dominated responses were similar; however, the subgroup with lymphocyte-dominated peri-prosthetic tissue responses had a significantly larger total number of particles. 14 cytokines (interleukin (IL)-1▀, IL-2, IL-4, IL-5, IL-6, IL-10, IL-13, IL-17, interferon (IFN)-?, andĀIFN-gamma-inducible protein 10), chemokines (macrophage inflammatory protein (MIP)-1? and MIP-1▀), and growth factors (granulocyte macrophage colony stimulating factor (GM-CSF) and platelet derived growth factor) were detected at significantly higher levels in patients with metal wear debris compared with the control group. Significantly higher levels for IL-1▀, IL-5, IL-10 and GM-CSF were found in the subgroup of tissues from failed MoM THAs with a lymphocyte-dominated peri-prosthetic response compared with those without this response. These results suggest that the 'biologically active area' predicts the type of peri-prosthetic tissue response. The cytokines IL-1▀, IL-5, IL-10, and GM-CSF are associated with lymphocyte-dominated tissue responses from failed small-diameter MoM THA. Cite this article: Bone Joint J 2015;97-B:917-23. PMID:26130346
Three to six-year results with the ultima metal-on-metal hip articulation for primary total hip arthroplasty
Michael Jacobs; Robert Gorab; David Mattingly; Lorence Trick; Carleton Southworth
One hundred seventy-one primary total hip arthroplasties were evaluated in a prospective, randomized study. Ninety-five involved a metal-backed cup with an all-metal liner and 76 involved a metal-backed polyethylene cup that was used as the control. All were implanted with an S-ROM cementless femoral component with a 28 mm head. The mean follow-up period was 3.7 years (range, 3.0¢5.7). The
Fracture of a dual-modular femoral component at the stem-sleeve junction in a metal-on-metal total hip arthroplasty.
Frank, Rachel M; Biswas, Debdut; Levine, Brett R
Innovations in the design of dual-modular femoral components have afforded surgeons several intraoperative advantages during both primary and revision total hip arthroplasty (THA). Although use of these implants has become more popular, the long-term outcomes and potential complications of introducing a second modular junction are still to be determined. In addition, concerns about corrosion potentiation at modular junctions in metal-on-metal (MOM) THA have arisen in recent studies. In this article, we present a unique case of fracture at the modular junction of the stem and modular sleeve of a dual-modular femoral component implanted with a MOM articulation. The proposed mechanisms of failure, including crevice and fretting corrosion as well as the potential effect of metal debris generated by MOM articulations, are reviewed. This case report is the first to describe component fracture at the stem-sleeve junction of this modern-generation dual-modular femoral component. Surgeons who encounter a painful dual-modular femoral stem must entertain this mode of failure and consider junctional failure as a potential diagnosis for such a patient, particularly in the setting of a MOM articulation. PMID:24660185
The Latest Lessons Learned from Retrieval Analyses of Ultra-High Molecular Weight Polyethylene, Metal-on-Metal, and Alternative Bearing Total Disc Replacements
Kurtz, Steven M.; Toth, Jeffrey M.; Siskey, Ryan; Ciccarelli, Lauren; MacDonald, Dan; Isaza, Jorge; Lanman, Todd; Punt, Ilona; Steinbeck, Marla; Goffin, Jan; van Ooij, Andrķ
Knowledge regarding the in vivo performance and periposthetic tissue response of cervical and lumbar total disc replacements (TDRs) continues to expand. This review addresses the following four main questions: 1) What are the latest lessons learned from polyethylene in large joints and how are they relevant to current TDRs? 2) What are the latest lessons learned regarding adverse local tissue reactions from metal-on-metal, CoCr bearings in large joints and how are they relevant to current TDRs? 3) What advancements have been made in understanding the in vivo performance of alternative biomaterials, such as stainless steel and polycarbonate urethane, for TDRs in the past five years? 4) How has retrieval analysis of all these various artificial disc bearing technologies advanced the state of the art in preclinical testing of TDRs? The study of explanted artificial discs and their associated tissues can help inform bearing selection as well as the design of future generations of disc arthroplasty. Analyzing retrieved artificial discs is also essential for validating preclinical test methods. PMID:22904606
Edge-loading severity as a function of cup lip radius in metal-on-metal total hips--a finite element analysis.
Elkins, Jacob M; Kruger, Karen M; Pedersen, Douglas R; Callaghan, John J; Brown, Thomas D
While favorable tribological properties and allowance for larger femoral head sizes have made metal-on-metal (MoM) bearings an increasingly popular choice for total hip arthroplasty, concerns have mounted regarding adverse reactions to metal wear debris and ions. MoM cups differ from conventional polyethylene cups in terms of edge profile design and reductions from full hemisphericity, suggesting differences in loading at or near the cup edge, especially during subluxation events. Finite element analysis was used to investigate the effects of cup orientation and lip edge curvature on damage propensity for edge or near-edge loading during subluxation. Increased cup lip radius (resulting in reduced articular arc) had a detrimental effect upon subluxation-free hip range of motion and upon dislocation resistance. Contact stresses near the cup edge demonstrated complex relationships between edge radius and cup orientation, with peak stresses being influenced by both variables. The tendency for scraping wear at the egress site demonstrated similarly complex dependencies. These data indicate that acetabular cup design is an important determinant of edge and near-edge loading damage propensity. PMID:21812025
Adverse reaction to metal debris after ReCap-M2A-Magnum large-diameter-head metal-on-metal total hip arthroplasty
Background and purpose The clinical findings of adverse reaction to metal debris (ARMD) following large-diameter-head metal-on-metal total hip arthroplasty (LDH MoM THA) may include periarticular fluid collections, soft tissue masses, and gluteal muscle necrosis. The ReCap-M2a-Magnum LDH MoM THA was the most commonly used hip device at our institution from 2005 to 2012. We assessed the prevalence of and risk factors for ARMD with this device. Methods 74 patients (80 hips) had a ReCap-M2a-Magnum LDH MoM THA during the period August 2005 to December 2006. These patients were studied with hip MRI, serum chromium and cobalt ion measurements, the Oxford hip score questionnaire, and by clinical examination. The prevalence of ARMD was recorded and risk factors for ARMD were assessed using logistic regression models. The mean follow-up time was 6.0 (5.5¢6.7) years. Results A revision operation due to ARMD was needed by 3 of 74 patients (3 of 80 hips). 8 additional patients (8 hips) had definite ARMD, but revision was not performed. 29 patients (32 hips) were considered to have a probable or possible ARMD. Altogether, 43 of 80 hips had a definite, probable, or possible ARMD and 34 patients (37 hips) were considered not to have ARMD. In 46 of 78 hips, MRI revealed a soft tissue mass or a collection of fluid (of any size). The symptoms clicking in the hip, local hip swelling, and a feeling of subluxation were associated with ARMD. Interpretation ARMD is common after ReCap-M2a-Magnum total hip arthroplasty, and we discourage the use of this device. Asymptomatic patients with a small fluid collection on MRI may not need instant revision surgery but must be followed up closely. PMID:24171688
Revision of a single type of large metal head metal-on-metal hip prosthesis.
van Lingen, Christiaan P; Ettema, Harmen B; Bosker, Bart H; Verheyen, Cees C P M
Large-head metal-on-metal (MoM) total hip arthroplasties were introduced because of their purported advantages. Inflammatory pseudotumours occasionally occur after MoM hip arthroplasty and often lead to revision. The purpose of this study was to assess the outcome of revision of large-head MoM total hip arthroplasties after an extensive screening protocol for all MoM articulations with a minimum 2 year follow-up. We identified 50 hips that had undergone large-head MoM total hip arthoplasty and required revision at a mean of 44 months after index operation. Of these, 38 were revised for pseudotumours, 7 for loosening, 2 for infection and 3 for instability. There was bone loss in 44 hips. The majority were revised to a 28 mm metal or ceramic head on a polyethylene-cemented cup. In 12 patients there was a complication. There was a decrease of whole blood cobalt from 20.8 Ąg/L preoperatively to 1.8 Ąg/L 1 year after revision. We found 6 residual masses on routine postoperative CT scans. The indication for revision of this cohort is inevitable but the clinical outcome 2 years after revision for pseudotumour is disappointing. Revising a MoM hip arthroplasty to a conventional cemented polyethylene or dual-mobility cup with bone impaction grafting and a 28 mm head can adequately treat the high ion levels and probably the disease of ARMD. PMID:25907389
Changes in early serum metal ion levels and impact on liver, kidney, and immune markers following metal-on-metal total hip arthroplasty.
Chen, Zhefeng; Wang, Zhen; Wang, Qing; Cui, Weiding; Liu, Feng; Fan, Weimin
We retrospectively studied 32 consecutive patients (32 hips) who underwent THA with a Durom large-head, MOM articulation between January 2008 and December 2010. Of the patients who underwent THA using a Trilogy metal on polyethylene prosthesis during the same period, 32 were chosen to form the Trilogy group. 32 volunteers were chosen to form the control group. At the last follow-up, serum metal ion levels, liver and kidney function and host immunologic immune responses were evaluated. The mean Co and Cr levels in the Durom group were 4.33- and 1.95-fold higher than those in the Trilogy group. CD3+, CD4+ and CD8+ cell levels in the Durom group were significantly decreased. The INF-? level in the Durom group was significantly higher than that in the Trilogy and control groups. PMID:23993737
Metal-on-Metal Hip Retrieval Analysis: A Case Report
Pace, Thomas B.; Rusaw, Kara A.; Minette, Lawrence J.; Shirley, Brayton R.; Snider, Rebecca G.; DesJardins, John D.
This is a case report involving a single case with severe bone and soft tissue destruction in a young male patient with a 10-year-metal on-metal total hip arthroplasty. Following complete aseptic erosion of the affected hip greater trochanter and abductor muscles, the hip was revised for recurrent instability. Histological examination of the patient's periprosthetic tissues, serological studies, and review of recent medical reports of similar cases were used to support an explanation of the destructive process and better contribute to our understanding of human reaction to metal debris in some patients following metal-on-metal hip arthroplasty. PMID:23840999
Silent soft tissue pathology is common with a modern metal-on-metal hip arthroplasty
Background and purpose Adverse reactions to metal debris have been reported to be a cause of pain in metal-on-metal hip arthroplasty. We assessed the incidence of both symptomatic and asymptomatic adverse reactions in a consecutive series of patients with a modern large-head metal-on-metal hip arthroplasty. Methods We studied the early clinical results and results of routine metal artifact-reduction MRI screening in a series of 79 large-head metal-on-metal hip arthroplasties (ASR; DePuy, Leeds, UK) in 68 patients. 75 hips were MRI scanned at mean 31 (12¢52) months after surgery. Results 27 of 75 hips had MRI-detected metal debris-related abnormalities, of which 5 were mild, 18 moderate, and 4 severe. 8 of these hips have been revised, 6 of which were revised for an adverse reaction to metal debris, diagnosed preoperatively with MRI and confirmed histologically. The mean Oxford hip score (OHS) for the whole cohort was 21. It was mean 23 for patients with no MRI-based evidence of adverse reactions and 19 for those with adverse reactions detected by MRI. 6 of 12 patients with a best possible OHS of 12 had MRI-based evidence of an adverse reaction. Interpretation We have found a high early revision rate with a modern, large-head metal-on-metal hip arthroplasty. MRI-detected adverse rections to metal debris was common and often clinically ōsilentö. We recommend that patients with this implant should be closely followed up and undergo routine metal artifact-reduction MRI screening. PMID:21504335
Edge loading in metal-on-metal hips: low clearance is a new risk factor
Zografos, Angelos; Sayles, Ritchie S; Hart, Alister; Cann, Philippa
The revision rate of large head metal-on-metal and resurfacing hips are significantly higher than conventional total hip replacements. The revision of these components has been linked to high wear caused by edge loading; which occurs when the head¢cup contact patch extends over the cup rim. There are two current explanations for this; first, there is loss of entrainment of synovial fluid resulting in breakdown of the lubricating film and second, edge loading results in a large local increase in contact pressure and consequent film thickness reduction at the cup rim, which causes an increase in wear. This paper develops a method to calculate the distance between the joint reaction force vector and the cup rim ¢ the contact patch centre to rim (CPCR) distance. However, the critical distance for the risk of edge loading is the distance from the contact patch edge to rim (CPER) distance. An analysis of explanted hip components, divided into edge worn and non-edge-worn components showed that there was no statistical difference in CPCR values, but the CPER value was significantly lower for edge worn hips. Low clearance hips, which have a more conformal contact, have a larger diameter contact patch and thus are more at risk of edge loading for similarly positioned hips. PMID:22558836
The minimal invasive direct anterior approach in combination with large heads in total hip arthroplasty - is dislocation still a major issue? a case control study
Background There have been increasing numbers of publications in recent years on minimally invasive surgery (MIS) for total hip arthroplasty (THA), reporting results with the use of different head sizes, tribologic and functional outcomes. This study presents the results and early complication rates after THA using the direct anterior approach (DAA) in combination with head sizes???36Āmm. Methods A total of 113 patients with THA were included in the study. The Harris Hip Score (HHS) was determined, a radiographic evaluation was carried out, and complications were recorded. The minimum follow-up period was 2Āyears (means 35?▒?7Āmonths). Results The HHS improved from 43.6 (▒ 12) to 88.2 (▒ 14; P?0.01). One early infection occurred, one periprosthetic fracture, and three cases of aseptic stem loosening. No incorrect positioning of the implants was observed, and there were no dislocations. Conclusion THA with the minimally invasive DAA in combination with large heads is associated with good to very good functional results in the majority of cases. The complication rates are not increased. The rate of dislocation mainly as an complication of the first two years can be markedly reduced in particular. PMID:24621189
Cobalt toxicity--an emerging clinical problem in patients with metal-on-metal hip prostheses?
Mao, Xinzhan; Wong, Andrew A; Crawford, Ross W
We report two Australian patients with possible cobalt toxicity related to metal-on-metal total hip replacements. Both patients were treated for osteoarthritis with a DePuy ASR (articular surface replacement) XL Acetabular Hip System prosthesis, which contains cobalt and chromium, and which has recently been recalled from the market. PMID:21692725
Metal-on-metal: history, state of the art (2010)
The history of metal-on-metal bearing began with K. Mc Kee. Several "episodes" have marked the history of metal-on-metal articulations, and each has contributed to a better understanding of this type of tribology. But to date the indications for this bearing are debated and are subject to reservations because of the existence of permanently elevated levels of circulating metal ions. It therefore appears that the monitoring of our patients, the documentation of our revisions and the collaboration with our industry partners as well as communicating with our biology and pathology colleagues is necessary to help us solve these problems. PMID:21234564
Taper junction failure in large-diameter metal-on-metal bearings
Langton, D. J.; Sidaginamale, R.; Lord, J. K.; Nargol, A. V. F.; Joyce, T. J.
Objectives An ongoing prospective study to investigate failing metal-on-metal hip prostheses was commenced at our centre in 2008. We report on the results of the analysis of the first consecutive 126 failed mated total hip prostheses from a single manufacturer. Methods Analysis was carried out using highly accurate coordinate measuring to calculate volumetric and linear rates of the articular bearing surfaces and also the surfaces of the taper junctions. The relationship between taper wear rates and a number of variables, including bearing diameter and orientation of the acetabular component, was investigated. Results The measured rates of wear and distribution of material loss from the taper surfaces appeared to show that the primary factor leading to taper failure is the increased lever arm acting on this junction in contemporary large-diameter metal-on-metal hip replacements. Conclusions Our analysis suggests that varus stems, laterally engaging taper systems and larger head diameters all contribute to taper failure. PMID:23610672
Tribological performance of various CoCr microstructures in metal-on-metal bearings: the development of a more physiological protocol in vitro.
Kamali, A; Hussain, A; Li, C; Pamu, J; Daniel, J; Ziaee, H; Daniel, J; McMinn, D J W
Hip simulators have been used for ten years to determine the tribological performance of large-head metal-on-metal devices using traditional test conditions. However, the hip simulator protocols were originally developed to test metal-on-polyethylene devices. We have used patient activity data to develop a more physiologically relevant test protocol for metal-on-metal devices. This includes stop/start motion, a more appropriate walking frequency, and alternating kinetic and kinematic profiles. There has been considerable discussion about the effect of heat treatments on the wear of metal-on-metal cobalt chromium molybdenum (CoCrMo) devices. Clinical studies have shown a higher rate of wear, levels of metal ions and rates of failure for the heat-treated metal compared to the as-cast metal CoCrMo devices. However, hip simulator studies in vitro under traditional testing conditions have thus far not been able to demonstrate a difference between the wear performance of these implants. Using a physiologically relevant test protocol, we have shown that heat treatment of metal-on-metal CoCrMo devices adversely affects their wear performance and generates significantly higher wear rates and levels of metal ions than in as-cast metal implants. PMID:20436012
CoCrMo Metal-on-Metal Hip Replacements
Liao, Yifeng; Hoffman, Emily; Wimmer, Markus; Fischer, Alfons; Jacobs, Joshua; Marks, Laurence
After the rapid growth in the use of CoCrMo metal-on-metal hip replacements since the second generation was introduced circa 1990, metal-on-metal hip replacements have experienced a sharp decline in the last two years due to biocompatibility issues related to wear and corrosion products. Despite some excellent clinical results, the release of wear and corrosion debris and the adverse response of local tissues have been of great concern. There are many unknowns regarding how CoCrMo metal bearings interact with the human body. This perspective article is intended to outline some recent progresses in understanding wear and corrosion of metal-on-metal hip replacement both in-vivo and in-vitro. The materials, mechanical deformation, corrosion, wear-assisted corrosion, and wear products will be discussed. Possible adverse health effects caused by wear products will be briefly addressed, as well as some of the many open questions such as the detailed chemistry of corrosion, tribochemical reactions and the formation of graphitic layers. Nowadays we design almost routinely for high performance materials and lubricants for automobiles; humans are at least as important. It is worth remembering that a hip implant is often the difference between walking and leading a relatively normal life, and a wheelchair. PMID:23196425
Metal-on-metal joint bearings and hematopoetic malignancy
Abstract This is a review of the hip arthroplasty era. We concentrate on new metal bearings, surface replacements, and the lessons not learned, and we highlight recent reports on malignancies and joint implants. A low incidence of blood malignancies has been found in bone marrow taken at prosthetic surgery. The incidence is increased after replacement with knee implants that release very low systemic levels of metal ions. A carcinogenic effect of the high levels of metal ions released by large metal-on-metal implants cannot be excluded. Ongoing Swedish implant registry studies going back to 1975 can serve as a basis for evaluation of this risk. PMID:23140092
Independent predictors of revision following metal-on-metal hip resurfacing: a retrospective cohort study using National Joint Registry data.
Jameson, S S; Baker, P N; Mason, J; Porter, M L; Deehan, D J; Reed, M R
Modern metal-on-metal hip resurfacing has been widely performed in the United Kingdom for over a decade. However, the literature reports conflicting views of the benefits: excellent medium- to long-term results with some brands in specific subgroups, but high failure rates and local soft-tissue reactions in others. The National Joint Registry for England and Wales (NJR) has collected data on all hip resurfacings performed since 2003. This retrospective cohort study recorded survival time to revision from a resurfacing procedure, exploring risk factors independently associated with failure. All patients with a primary diagnosis of osteoarthritis who underwent resurfacing between 2003 and 2010 were included in the analyses. Cox's proportional hazard models were used to analyse the extent to which the risk of revision was related to patient, surgeon and implant covariates. A total of 27 971 hip resurfacings were performed during the study period, of which 1003 (3.59%) underwent revision surgery. In the final adjusted model, we found that women were at greater risk of revision than men (hazard ratio (HR) = 1.30, p = 0.007), but the risk of revision was independent of age. Of the implant-specific predictors, five brands had a significantly greater risk of revision than the Birmingham Hip Resurfacing (BHR) (ASR: HR = 2.82, p < 0.001, Conserve: HR = 2.03, p < 0.001, Cormet: HR = 1.43, p = 0.001, Durom: HR = 1.67, p < 0.001, Recap: HR = 1.58, p = 0.007). Smaller femoral head components were also significantly more likely to require revision (? 44 mm: HR = 2.14, p < 0.001, 45 to 47 mm: HR = 1.48, p = 0.001) than medium or large heads, as were operations performed by low-volume surgeons (HR = 1.36, p < 0.001). Once these influences had been removed, in 4873 male patients < 60 years old undergoing resurfacing with a BHR, the five-year estimated risk of revision was 1.59%. In summary, after adjustment for a range of covariates we found that there were significant differences in the rate of failure between brands and component sizes. Younger male patients had good five-year implant survival when the BHR was used. PMID:22628587
Metal Ion Concentrations in Body Fluids after Implantation of Hip Replacements with Metal-on-Metal Bearing ¢ Systematic Review of Clinical and Epidemiological Studies
Hartmann, Albrecht; Hannemann, Franziska; L³tzner, J÷rg; Seidler, Andreas; Drexler, Hans; G³nther, Klaus-Peter; Schmitt, Jochen
Introduction The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds) in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. Objective To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. Methods Systematic review of clinical trials (RCTs) and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum) in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor), patient characteristics as well as study quality characteristics (secondary explanatory factors). Results Overall, 104 studies (11 RCTs, 93 epidemiological studies) totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine) irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 Ąg/L were measured (detection limit typically 0.3 Ąg/L). Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. Discussion Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed ätime outō for stemmed large-head MoM-THA and recommend a restricted indication for hip resurfacing arthroplasty. Patients with implanted MoM-bearing should receive regular and standardized monitoring of metal ion concentrations. Further research is indicated especially with regard to potential systemic reactions due to accumulation of metal products. PMID:23950923
Wear of surface engineered metal-on-metal hip prostheses.
Fisher, J; Hu, X Q; Stewart, T D; Williams, S; Tipper, J L; Ingham, E; Stone, M H; Davies, C; Hatto, P; Bolton, J; Riley, M; Hardaker, C; Isaac, G H; Berry, G
The wear of existing metal-on-metal (MOM) hip prostheses (1 mm3/million cycles) is much lower than the more widely used polyethylene-on-metal bearings (30-100 mm3/million cycles). However, there remain some potential concerns about the toxicity of metal wear particles and elevated metal ion levels, both locally and systemically in the human body. The aim of this study was to investigate the wear, wear debris and ion release of fully coated surface engineered MOM bearings for hip prostheses. Using a physiological anatomical hip joint simulator, five different bearing systems involving three thick (8-12 microm) coatings, TiN, CrN and CrCN, and one thin (2 microm) coating diamond like carbon (DLC) were evaluated and compared to a clinically used MOM cobalt chrome alloy bearing couple. The overall wear rates of the surface engineered prostheses were at least 18-fold lower than the traditional MOM prostheses after 2 million cycles and 36-fold lower after 5 million cycles. Consequently, the volume of wear debris and the ion levels in the lubricants were substantially lower. These parameters were also much lower than in half coated (femoral heads only) systems that have been reported previously. The extremely low volume of wear debris and concentration of metal ions released by these surface engineered systems, especially with CrN and CrCN coatings, have considerable potential for the clinical application of this technology. PMID:15334994
Microseparation, fluid pressure and flow in failures of metal-on-metal hip resurfacing arthroplasties
Wroblewski, B. M.; Siney, P. D.; Fleming, P. A.
Objectives Metal-on-metal (MoM) hip resurfacing was introduced into clinical practice because it was perceived to be a better alternative to conventional total hip replacement for young and active patients. However, an increasing number of reports of complications have arisen focusing on design and orientation of the components, the generation of metallic wear particles and serum levels of metallic ions. The procedure introduced a combination of two elements: large-dimension components and hard abrasive particles of metal wear. The objective of our study was to investigate the theory that microseparation of the articular surfaces draws in a high volume of bursal fluid and its contents into the articulation, and at relocation under load would generate high pressures of fluid ejection, resulting in an abrasive water jet. Methods This theoretical concept using MoM resurfacing components (head diameter 55 mm) was modelled mathematically and confirmed experimentally using a material-testing machine that pushed the head into the cup at a rate of 1000 mm/min until fully engaged. Results The mathematical model showed the pattern but not the force of fluid ejection, the highest pressures were expected when the separation of the components was only a fraction of one millimetre. The experimental work confirmed the results; with the mean peak ejection pressure of 43 763 N/m2 equivalent to 306 mmHg or 5 psi. Conclusions The mechanical effect of the high-pressure abrasive water jet is the likely cause of the spectrum of complications reported with metal-on-metal resurfacing. Investigating serum levels of metallic elements may not be the best method for assessing the local mechanical effects of the abrasive water jet. PMID:23610667
On the inflammatory response in metal-on-metal implants
Background Metal-on-metal implants are a special form of hip endoprostheses that despite many advantages can entail serious complications due to release of wear particles from the implanted material. Metal wear particles presumably activate local host defence mechanisms, which causes a persistent inflammatory response with destruction of bone followed by a loosening of the implant. To better characterize this inflammatory response and to link inflammation to bone degradation, the local generation of proinflammatory and osteoclast-inducing cytokines was analysed, as was systemic T cell activation. Methods By quantitative RT-PCR, gene expression of cytokines and markers for T lymphocytes, monocytes/macrophages and osteoclasts, respectively, was analysed in tissue samples obtained intraoperatively during exchange surgery of the loosened implant. Peripheral T cells were characterized by cytofluorometry before surgery and 7 to 10Ādays thereafter. Results At sites of osteolysis, gene expression of cathepsin K, CD14 and CD3 was seen, indicating the generation of osteoclasts, and the presence of monocytes and of T cells, respectively. Also cytokines were highly expressed, including CXCL8, IL-1▀, CXCL2, MRP-14 and CXCL-10. The latter suggest T cell activation, a notion that could be confirmed by detecting a small, though conspicuous population of activated CD4+ cells in the peripheral blood T cells prior to surgery. Conclusion Our data support the concept that metallosis is the result of a local inflammatory response, which according to histomorphology and the composition of the cellular infiltrate classifies as an acute phase of a chronic inflammatory disease. The proinflammatory environment, particularly the generation of the osteoclast-inducing cytokines CXCL8 and IL1-▀, promotes bone resorption. Loss of bone results in implant loosening, which then causes the major symptoms of metallosis, pain and reduced range of motion. PMID:24650243
Muscle atrophy and metal-on-metal hip implants
Berber, Reshid; Khoo, Michael; Cook, Erica; Guppy, Andrew; Hua, Jia; Miles, Jonathan; Carrington, Richard; Skinner, John; Hart, Alister
Background and purpose Muscle atrophy is seen in patients with metal-on-metal (MOM) hip implants, probably because of inflammatory destruction of the musculo-tendon junction. However, like pseudotumors, it is unclear when atrophy occurs and whether it progresses with time. Our objective was to determine whether muscle atrophy associated with MOM hip implants progresses with time. Patients and methods We retrospectively reviewed 74 hips in 56 patients (32 of them women) using serial MRI. Median age was 59 (23¢83) years. The median time post-implantation was 83 (35¢142) months, and the median interval between scans was 11 months. Hip muscles were scored using the Pfirrmann system. The mean scores for muscle atrophy were compared between the first and second MRI scans. Blood cobalt and chromium concentrations were determined. Results The median blood cobalt was 6.84 (0.24¢90) ppb and median chromium level was 4.42 (0.20¢45) ppb. The median Oxford hip score was 34 (5¢48). The change in the gluteus minimus mean atrophy score between first and second MRI was 0.12 (p = 0.002). Mean change in the gluteus medius posterior portion (unaffected by surgical approach) was 0.08 (p = 0.01) and mean change in the inferior portion was 0.10 (p = 0.05). Mean pseudotumor grade increased by 0.18 (p = 0.02). Interpretation Worsening muscle atrophy and worsening pseudotumor grade occur over a 1-year period in a substantial proportion of patients with MOM hip implants. Serial MRI helps to identify those patients who are at risk of developing worsening soft-tissue pathology. These patients should be considered for revision surgery before irreversible muscle destruction occurs. PMID:25588091
Assessing the material loss of the modular taper interface in retrieved metal-on-metal hip replacements
NASA Astrophysics Data System (ADS)
Bills, Paul J.; Racasan, R.; Tessier, P.; Blunt, L. A.
Measuring the amount of material loss in the case of revised hip replacements is considered to be a prerequisite of understanding and assessing the true in vivo performance of the implant. This paper outlines a method developed by the authors for quantifying taper material loss as well as more general taper interface parameters. Previous studies have mostly relied on visual inspection to assess the material loss at the taper interface, whereas this method aims to characterize any surface and form changes through the use of an out-of-roundness measurement machine. Along with assessing the volumetric wear, maximum linear penetration and taper contact length can also be determined. The method was applied to retrieved large head metal-on-metal femoral heads in order to quantify the material loss at this junction. Material loss from the female femoral head taper can be characterized as a localized area that is in contact with the stem taper surface. The study showed that this method has good repeatability and a low level of interoperability variation between operators.
THA Using Metal-on-Metal Articulation in Active Patients Younger Than 50ĀYears
Bonnomet, Franńois; Clavert, Philippe; Laffargue, Philippe; Migaud, Henri
The main concern of patients with longer life expectancies and of patients who are younger and more active is the longevity of their total hip arthroplasty. We retrospectively reviewed 83 cementless total hip arthroplasties in 73 patients implanted with metal-on-metal articulation. All patients were younger than 50Āyears old (average age, 41Āyears) at the time of the index procedure, and 80% of the patients had an activity level graded 4 or 5 when measured with the system of Devane etĀal. A 28-mm Metasul articulation was used with three different cementless titanium acetabular components. At the most recent followup (average, 7.3Āyears), the average Merle dÆAubignķ-Postel score improved from a preoperative 11.1 points to 17.4 points. We observed no radiographic evidence of component loosening. Ten acetabular components had lucency limited to one zone. The 10-year survivorship with the end point of revision (ie, exchange of at least one prosthetic or bearing component) was 100% (95% confidence interval, 90%¢100%). Metasul bearings with cementless acetabular components remain promising in this high-risk younger patient population. However, additional followup strategies are recommended to determine any possible long-term deleterious effects associated with the dissemination of metallic ions. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18196415
Ultrasound screening of periarticular soft tissue abnormality around metal-on-metal bearings.
Nishii, Takashi; Sakai, Takashi; Takao, Masaki; Yoshikawa, Hideki; Sugano, Nobuhiko
Although metal hypersensitivity or pseudotumors are concerns for metal-on-metal (MoM) bearings, detailed pathologies of patterns, severity, and incidence of periprosthetic soft tissue lesions are incompletely understood. We examined the potential of ultrasound for screening of periarticular soft tissue lesions around MoM bearings. Ultrasound examinations were conducted in 88 hips (79 patients) with MoM hip resurfacings or MoM total hip arthroplasties with a large femoral head. Four qualitative ultrasound patterns were shown, including normal pattern in 69 hips, joint-expansion pattern in 11 hips, cystic pattern in 5 hips, and mass pattern in 3 hips. Hips with the latter 3 abnormal patterns showed significantly higher frequency of clinical symptoms, without significant differences of sex, duration of implantation, head sizes, and cup abduction/anteversion angles, compared with hips with normal pattern. Ultrasound examination provides sensitive screening of soft tissue reactions around MoM bearings and may be useful in monitoring progression and defining treatment for periarticular soft tissue abnormalities. PMID:22047978
Tribolayer Formation in a Metal-on-Metal (MoM) Hip Joint: An Electrochemical Investigation
Mathew, MT; Nagelli, C; Pourzal, R; Fischer, A; Laurent, MP; Jacobs, JJ; Wimmer, MA
The demand for total hip replacement (THR) surgery is increasing in the younger population due to faster rehabilitation and more complete restoration of function. Up to 2009, metal-on-metal (MoM) hip joint bearings were a popular choice due to their design flexibility, post-operative stability and relatively low wear rates. The main wear mechanisms that occur along the bearing surface of MoM joints are tribochemical reactions that deposit a mixture of wear debris, metal ions and organic matrix of decomposed proteins known as a tribolayer. No in-depth electrochemical studies have been reported on the structure and characteristics of this tribolayer or about the parameters involved in its formation. In this study, we conducted an electrochemical investigation of different surfaces (bulk-like: control, nano-crystalline: new implant and tribolayer surface: retrieved implant) made out of two commonly used hip CoCrMo alloys (high-carbon and low-carbon). As per ASTM standard, cyclic polarization tests and electrochemical impedance spectroscopy tests were conducted. The results obtained from electrochemical parameters for different surfaces clearly indicated a reduction in corrosion for the tribolayer surface (Icorr: 0.76 ?A/cm2). Further, polarization resistance (Rp:2.39▒0.60M?/cm2) and capacitance (Cdl:15.20▒0.75 ?F/cm2) indicated variation in corrosion kinetics for the tribolayer surface, that attributed to its structure and stability in a simulated body environment. PMID:24099949
The Durom large diameter head acetabular component: early results with a large-diameter metal-on-metal bearing.
Berton, C; Girard, J; Krantz, N; Migaud, H
Implantation of a large-diameter femoral head prosthesis with a metal-on-metal bearing surface reduces the risk of dislocation, increases the range of movement, minimises the risk of impingement and, in theory, results in little wear. Between February 2004 and March 2007 we implanted 100 consecutive total hip replacements with a metal-on-metal bearing and a large femoral head into 92 patients. There were 51 men and 41 women with a mean age of 50 years (18 to 70) at the time of surgery. Outcome was assessed using the Western Ontario McMaster University osteoarthritis index and the Harris hip score as well as the Devane activity score. These all improved significantly (p < 0.0001). At the last follow-up there were no cases of dislocation, no impingement, a good range of movement and no osteolysis, but seven revisions, two for infection and five for aseptic loosening. The probability of groin pain increased if the other acetabular component inclination exceeded 50 degrees (p = 0.0007). At 4.8 years of follow-up, the projected survival of the Durom acetabular component, with revision for any reason, was 92.4% (sd 2.8) (95% confidence interval 89.6 to 95.2). The design of the component made it difficult both to orientate and seat, which when combined with a poor porous coating, produced unpredictable fixation and a low survival at five years. PMID:20130309
Does Ion Release Differ Between Hip Resurfacing and Metal-on-metal THA?
Moroni, Antonio; Cadossi, Matteo; Baldini, Nicola; Giannini, Sandro
Modern metal-on-metal hip resurfacing was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potential increased metal ion release. We hypothesized there were no differences in serum concentrations of chromium, cobalt, and molybdenum between patients who had metal-on-metal hip resurfacing (Group A; average head diameter, 48Āmm; median followup, 24Āmonths) and patients who had 28-mm metal-on-metal THA (Group B; median followup, 25Āmonths). Serum concentrations also were compared with concentrations in healthy subjects. We identified no differences in ion levels between Groups A and B. A distinction was made according to gender. Women showed a higher chromium release in Group A whereas men had a higher cobalt release in Group B. Values obtained from Group A were higher than those of the control subjects. Our data suggest metal-on-metal bearings for THA should not be rejected because of concern regarding potential increased metal ion release; however, patients with elevated ion levels, even without loosening or toxicity, could be at higher risk and should be followed up periodically. Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18196364
New Insights into Wear and Biological Effects of Metal-on-Metal Bearings
Catelas, Isabelle; Wimmer, Markus A.
Background: Despite the renewed interest in metal-on-metal implants in the past two decades, the underlying wear mechanisms and biological effects are still not fully understood. Methods: This paper first reviews the tribology of metal-on-metal bearings, bringing new insights into the interaction of wear and corrosion, and putting the characteristics and the potential origin of wear particles in perspective with the proposed wear mechanisms. It then summarizes the current knowledge on the biological effects of particles and metal ions in relation to these wear mechanisms. Results: Tribochemical reactions play an important role in the wear of metal-on-metal joints. The generated tribomaterial, which progressively forms by mechanical mixing of the uppermost nanocrystalline zone of the metal surface with proteins from the synovial fluid, governs the wear rate and influences the corrosive behavior of the bearing. Nanometer-sized wear particles may initially originate from the passivation layer covering the implant surface and then detach from this tribolayer. The inflammatory response observed surrounding metal-on-metal implants appears to be lower than that around metal-on-polyethylene implants. However, metallic byproducts, which can complex with proteins, may lead to a T lymphocyte-mediated hypersensitivity response. Conclusions: The tribolayer appears to have beneficial effects on the wear rate. Much information has been gained on wear particle characteristics, but the exact mechanisms of particle detachment remain to be further elucidated. Excessive wear along with a hypersensitivity response may be at the origin of the early adverse tissue reactions that have been recently reported in some patients with metal-on-metal implants. Clinical Relevance: Future development of new methods to improve the tribolayer retention and optimize the tribocorrosive properties of the implant may minimize the clinical impact of implant wear and immune responses. PMID:21543694
Metal-on-Metal Hip Prostheses and Systemic Health: A Cross-Sectional Association Study 8 Years after Implantation
Prentice, Jennifer R.; Clark, Matthew J.; Hoggard, Nigel; Morton, Allison C.; Tooth, Claire; Paley, Martyn N.; Stockley, Ian; Hadjivassiliou, Marios; Wilkinson, J. Mark
There is public concern over the long term systemic health effects of metal released from hip replacement prostheses that use large-diameter metal-on-metal bearings. However, to date there has been no systematic study to determine which organs may be at risk, or the magnitude of any effect. We undertook a detailed cross-sectional health screen at a mean of 8 years after surgery in 35 asymptomatic patients who had previously received a metal-on-metal hip resurfacing (MoMHR) versus 35 individually age and sex matched asymptomatic patients who had received a conventional hip replacement. Total body bone mineral density was 5% higher (mean difference 0.05 g/cm2, P?=?0.02) and bone turnover was 14% lower (TRAP 5b, mean difference ?0.56IU/L, P?=?0.006; osteocalcin, mean difference ?3.08 ng/mL, P?=?0.03) in the hip resurfacing versus conventional hip replacement group. Cardiac ejection fraction was 7% lower (mean absolute difference ?5%, P?=?0.04) and left ventricular end-diastolic diameter was 6% larger (mean difference 2.7 mm, P?=?0.007) in the hip resurfacing group versus those patients who received a conventional hip replacement. The urinary fractional excretion of metal was low (cobalt 5%, chromium 1.5%) in patients with MoMHR, but creatinine clearance was normal. Diuretic prescription was associated with a 40% increase in the fractional excretion of chromium (mean difference 0.5%, P?=?0.03). There was no evidence of difference in neuropsychological, renal tubular, hepatic or endocrine function between groups (P>0.05). Our findings of differences in bone and cardiac function between patient groups suggest that chronic exposure to low elevated metal concentrations in patients with well-functioning MoMHR prostheses may have systemic effects. Long-term epidemiological studies in patients with well-functioning metal on metal hip prostheses should include musculoskeletal and cardiac endpoints to quantitate the risk of clinical disease. PMID:23762480
Cementless acetabular socket revisions using Metasul metal-on-metal bearings.
Park, Kyung Soon; Yoon, Taek Rim; Song, Eun Kyoo; Lee, Keun Bae
Thirty-four hips were treated with cementless acetabular socket revisions using a metal-on-metal bearing. The causes of revision were aseptic loosening in 33 hips and septic loosening in 1 hip. Revisions were performed for acetabular sockets in 28 hips and for acetabular sockets and femoral stems in 6 hips. Mean follow-up duration was 6.2 years (range, 4.0-9.1 years), and mean Harris Hip Scores improved from 56 to 92 points. No hip required further revision for aseptic loosening. Focal femoral osteolysis newly developed in zone I in 1 hip, which was treated by curettage and bone grafting. The authors suggest that second-generation metal-on-metal bearings in cementless acetabular socket revisions can achieve good medium-term clinical and radiographic results. PMID:19493650
A retrieval analysis of explanted Durom metal-on-metal hip arthroplasties.
Matthies, Ashley K; Henckel, Johann; Skinner, John A; Hart, Alister J
Given the recent reports of high failure rates, an improved understanding of the mechanism of failure of large diameter metal-on-metal hip arthroplasties is essential. We present clinical data and tribological analysis of a consecutive series of 74 failed large diameter metal-on-metal hips, comparing the Durom (Zimmer) with the Birmingham hip resurfacing (BHR) (Smith and Nephew). We retrospectively analysed pre-, intra-, and post-operative clinical data and measured the linear wear and component form of the explanted components using a roundness measuring machine. A significantly higher proportion of hips in the Durom group failed as a result of acetabular loosening (p=0.001) and this was supported by evidence of reduced bone in-growth on the backside of the cup. Comparison of roundness measurement revealed that the Durom hip was significantly lower wearing than the BHR (p<0.05) but the Durom femoral components were subject to significantly greater form errors (p<0.001), the pole of the head being flattened by up to 31 microns. Although the Durom hip is low wearing, reduced sphericity of the femoral component may have resulted in equatorial bearing, leading to an increased frictional torque at the cup-bone interface, preventing bone in-growth, and culminating in acetabular loosening. This supports recent clinical findings of high revision rates as a result of acetabular loosening for the Durom metal-on-metal hip system. PMID:22144337
Metal-on-Metal Hip Arthroplasty: A Review of Adverse Reactions and Patient Management.
Drummond, James; Tran, Phong; Fary, Camdon
Recent alarming joint registry data highlighting increased revision rates has prompted further research into the area of metal-on-metal hip replacements and resurfacings. This review article examines the latest literature on the topic of adverse reactions to metal debris and summarises the most up-to-date guidelines on patient management. Adverse reactions to metal debris can cause significant damage to soft tissue and bone if not diagnosed early. Furthermore, not every patient with an adverse reaction to metal debris will be symptomatic. As such, clinicians must remain vigilant when assessing and investigating these patients in order to detect failing implants and initiate appropriate management. PMID:26132653
Metal-on-metal local tissue reaction is associated with corrosion of the head taper junction.
Fricka, Kevin B; Ho, Henry; Peace, William J; Engh, Charles A
We evaluated taper corrosion in 36-mm diameter metal-on-metal (MOM) and metal-on-polyethylene (MOP) femoral heads from a single manufacturer retrieved for various reasons. Three reviewers visually graded taper corrosion with a 5-point scale on 19 MOM heads and 14 MOP heads. The MOM group had a higher corrosion score than the MOP group (mean, 3.5 vs 1.9; P < .001). There were 8 MOM heads (42%) and only 1 MOP head (7%) that demonstrated corrosion outside of the taper zone. Metal-on-metal patients revised secondary to adverse local tissue reactions (ALTRs) had greater scores than patients without ALTRs (mean, 4.36 vs 2.38; P < .01). Adverse local tissue reactions MOM patients were also likely to have corrosion outside of the taper junction. The corrosion score increased with implantation time, and at all time intervals, the corrosion score for the MOM group was greater. Because corrosion worsens with time, we are concerned that MOM ALTR failures will increase with longer follow-up. PMID:22554728
Surface engineering: a low wearing solution for metal-on-metal hip surface replacements.
Leslie, Ian J; Williams, Sophie; Brown, Chris; Anderson, James; Isaac, Graham; Hatto, Peter; Ingham, Eileen; Fisher, John
Increased patient blood and serum levels of Co and Cr and dissemination of metal wear particles throughout organs and tissues are the primary concerns with metal-on-metal surface replacements. Surface engineering, providing a ceramic bearing surface on a metal substrate, could provide a solution. This study investigated thick (>10 microm) arc evaporation plasma vapor deposition chromium nitride (CrN) coated surface replacements in terms of wear, ion levels, and wear particles in a 10 million cycle hip simulator study, compared to a contemporary metal-on-metal surface replacement. The ion levels were measured by inductively coupled plasma mass spectroscopy. The wear particles were imaged by field emission gun scanning electron microscopy. The CrN-coated bearings had 80% lower wear than the MoM controls. The Cr and Co ion levels in the lubricant of the CrN bearings were 73 and 98% lower than in the MoM controls. The wear particles produced were in the nanometer size range and round to oval in morphology. The CrN coating could provide a reduction in the wear and ion release of MoM surface replacements, thereby reducing the perceived risks to the patient associated with these prostheses. PMID:19195030
The effect of microstructure on the wear of cobalt-based alloys used in metal-on-metal hip implants.
Varano, R; Bobyn, J D; Medley, J B; Yue, S
The influence of microstructure on the wear of cobalt-based alloys used in metal-on-metal hip implants was investigated in a boundary lubrication regime designed to represent the conditions that occurred some of the time in vivo. These cobalt-chromium-molybdenum alloys were either wrought, with a total carbon content of 0.05 or 0.23 wt %, cast with a solution-annealing procedure or simply as-cast but not solution annealed. Bars of these different alloy grades were subjected to various heat treatments to develop different microstructures. The wear was evaluated in a linear-tracking reciprocating pin-on-plate apparatus with a 25 per cent bovine serum lubricant. The wear was found to be strongly affected by the dissolved carbon content of the alloys and mostly independent of grain size or the carbide characteristics. The increased carbon in solid solution caused reductions in volumetric wear because carbon helped to stabilize a face-centred cubic crystal structure, thus limiting the amount of strain-induced transformation to a hexagonal close-packed crystal structure. Based on the observed surface twining in and around the contact zone and the potentially detrimental effect of the hexagonal close-packed phase, it was postulated that the wear of cobalt-based alloys in the present study was controlled by a deformation mechanism. PMID:16669383
Metal ion levels after metal-on-metal proximal femoral replacements: a 30-year follow-up.
Dunstan, E; Sanghrajka, A P; Tilley, S; Unwin, P; Blunn, G; Cannon, S R; Briggs, T W R
Metal-on-metal hip bearings are being implanted into younger patients. The consequence of elevated levels of potentially carcinogenic metal ions is therefore a cause for concern. We have determined the levels of cobalt (Co), chromium (Cr), titanium (Ti) and vanadium (Va) in the urine and whole blood of patients who had had metal-on-metal and metal-on-polyethylene articulations in situ for more than 30 years. We compared these with each other and with the levels for a control group of subjects. We found significantly elevated levels of whole blood Ti, Va and urinary Cr in all arthroplasty groups. The whole blood and urine levels of Co were grossly elevated, by a factor of 50 and 300 times respectively in patients with loose metal-on-metal articulations when compared with the control group. Stable metal-on-metal articulations showed much lower levels. Elevated levels of whole blood or urinary Co may be useful in identifying metal-on-metal articulations which are loose. PMID:15855362
Formation of molten metal films during metal-on-metal slip under extreme interfacial conditions
NASA Astrophysics Data System (ADS)
Liou, Nai-Shang; Okada, Makoto; Prakash, Vikas
The present paper describes results of plate-impact pressure-shear friction experiments conducted to study time-resolved growth of molten metal films during dry metal-on-metal slip under extreme interfacial conditions. By employing tribo-pairs comprising hard tool-steel against relatively low melt-point metals such as 7075-T6 aluminum alloys, interfacial friction stress ranging from 100 to 400 MPa and slip speeds of approximately 100 m/ s have been generated. These relatively high levels of friction stress combined with high slip-speeds generate conditions conducive for interfacial temperatures to approach the melting point of the lower melt point metal (Al alloy) comprising the tribo-pair. A Lagrangian finite element code is developed to understand the evolution of the thermo-mechanical fields and their relationship to the observed slip response. The code accounts for dynamic effects, heat conduction, contact with friction, and full thermo-mechanical coupling. At temperatures below the melting point the material is described as an isotropic thermally softening elastic-viscoplastic solid. For material elements with temperatures in excess of the melt point a purely Newtonian fluid constitutive model is employed. The results of the hybrid experimental-computational study provides new insights into the thermoelastic-plastic interactions during high speed metal-on-metal slip under extreme interfacial conditions. During the early part of frictional slip the coefficient of kinetic friction is observed to decrease with increasing slip velocity. During the later part transition in interfacial slip occurs from dry metal-on-metal sliding to the formation of molten Al films at the tribo-pair interface. Under these conditions the interfacial resistance approaches the shear strength of the molten aluminum alloy under normal pressures of approximately 1- 3 GPa and shear strain rates of ś10 7 s-1. The results of the study indicate that under these extreme conditions molten aluminum films maintain a shearing resistance as high as 100 MPa. Scanning electron microscopy of the slip surfaces reveal molten aluminum to be smeared on the tribo-pair interface. Knoop hardness measurements in 7075-T6 Al alloy at various depths from the slip interface indicate that the hardness increases approximately linearly with depth and reaches a plateau at approximately 40 ?m from the surface.
Outcomes after revision of metal-on-metal hip resurfacing arthroplasty.
Gross, Thomas P; Liu, Fei
We report the results of 58 hip resurfacing arthroplasties (HRA) revised by a single surgeon with an average of 5.2▒2.6 years follow-up. The four most common causes for revision were acetabular component loosening, femoral neck fracture, femoral component loosening, and adverse wear related failure (AWRF). In 95% of cases (55/58), the revision bearing was a large metal-on-metal type including all seven AWRF cases; three cases were revised to ceramic-on-polyethylene. There were two repeat revisions due to acetabular component loosening. Revision of AWRF had an excellent outcome using limited debridement and a stable large metal bearing placed in the correct position. The only problematic group was the one revised for acetabular loosening in which 2/16 (6%) required repeat revision for failure of acetabular fixation. PMID:24997652
The effect of acetabular inclination on metal ion levels following metal-on-metal hip arthroplasty.
Emmanuel, Andrew R; Bergin, Karen M; Kelly, Gabrielle E; McCoy, Gerald F; Wozniak, Andrew P; Quinlan, John F
Acetabular inclination angles have been suggested as a principal determinant of circulating metal ion levels in metal-on-metal hip arthroplasties. We aimed to determine whether inclination angle correlates with ion levels in arthroplasties using the Articular Surface Replacement (ASR) system. Patients undergoing ASR arthroplasties had blood metal ion levels and radiograph analysis performed a mean of 3.2 years after surgery. Inclination angle showed only a weak correlation with cobalt (r=0.21) and chromium (r=0.15) levels. The correlation between inclination angle and cobalt levels was significant only with small femoral components, although it was still weak. Multiple regression showed a complex interaction of factors influencing ion levels but inclination angle accounted for little of this variation. We conclude that the acetabular inclination angle is not a meaningful determinant of metal ion levels in ASR arthroplasties. PMID:23759116
Histological characterization of periprosthetic tissue responses for metal-on-metal hip replacement
Phillips, Eual A.; Klein, Gregg R.; Cates, Harold E.; Kurtz, Steven M.; Steinbeck, Marla J.
The histology of periprosthetic tissue from metal-on-metal (MOM) hip devices has been characterized by a variety of methods. The purpose of this study was to compare and evaluate the suitability of two previously developed aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL) scoring systems for periprosthetic hip tissue responses retrieved from MOM THR systems revised for loosening. Two ALVAL scoring systems (Campbell and Oxford) were used to perform histological analysis of soft tissues from seventeen failed MOM THRs. The predominant reactions for this patient cohort were macrophage infiltration and necrosis, with less than half of the patients (41%) showing a significant lymphocytic response or a high ALVAL reaction (6%). Other morphological changes which varied among patients included hemosiderin accumulation, cartilage formation and heterotopic ossification. Both scoring systems correlated with macrophage and lymphocyte responses and with each other, however given the diversity and variability of the current responses the Oxford-ALVAL system was more suitable for scoring tissues from MOM THR patients revised for loosening. It is important that standardized methods to score MOM tissue responses be used consistently so multiple study results can be compared to one another and a consensus can be generated. PMID:24941402
Fast growing pseudotumour in a hairdresser after metal-on-metal hip resurfacing: a case report.
Cadossi, M; Chiarello, E; Savarino, L; Mazzotti, A; Tedesco, G; Greco, M; Giannini, S
A 44-year-old female hairdresser who underwent metal-on-metal hip resurfacing (MOMHR) for hip osteoarthritis developed a benign pelvic pseudotumour. Elevated levels of chromium and cobalt ions were detected in the blood. Patch testing after pseudotumor formation, showed positive skin reactions to cobalt and nickel. Marked hypereosinophilia was noted, as well as the presence of eosinophils in the pseudotumor mass. A revision to a ceramic-on-ceramic implant was performed. Radiographs showed no implant loosening or bone resorption. We hypothesized that a steep cup positioning as well as hypersensitivity response to the metal nanoparticles and ion release may have induced pseudotumour development. Currently there is no evidence that negative patch testing reduces the probability to develop an adverse reaction to metal debris therefore we suggest to carefully investigate patient medical history regarding occupation exposure and daily contact with jewellery, beauty and cleaning products before implanting MOMHR. The main challenge is to identify a sensitive patient candidate to MOMHR never suspected to be. PMID:24825038
Transient thermo-mechanical interactions during high-speed slip at metal-on-metal interfaces
NASA Astrophysics Data System (ADS)
Liou, N. S.; Okada, M.; Irfan, M. A.; Prakash, V.
The paper describes results obtained from plate-impact pressure-shear friction experiments to investigate the phenomena of high-speed slip at metal-on-metal interfaces. Using a CH tool-steel/Ti-6Al-4V tribo-pair the authors have studied the effects of normal pressure, slip-speed, temperature and surface roughness on the evolution of the dynamic slip-resistance. Moreover, a finite-element procedure is developed to simulate the evolution of thermo-mechanical fields and understand their relationship to the observed slip response. Next, the pressure-shear friction experiments are extended to investigate the behavior of CH tool-steel/7075-T6 Al alloy tribo-pair. This material combination allows dynamic friction characteristics to be studied in the near-melt and the fully melt temperature regime of the lower-melting-point metal (7075-T6 Al alloy) comprising the tribo-pair. Besides providing information on the slip-velocity versus friction-stress relationship under extreme interfacial conditions, the experiments provides critical information on the shearing resistance of confined molten metal films under high pressures and extremely high shearing rates.
A lexicon for wear of metal-on-metal hip prostheses.
McKellop, Harry A; Hart, Alister; Park, Sang-Hyun; Hothi, Harry; Campbell, Pat; Skinner, John A
Research on metal-on-metal (MoM) hip bearings has generated an extensive vocabulary to describe the wear processes and resultant surface damage. However, a lack of consistency and some redundancy exist in the current terminology. To facilitate the understanding of MoM tribology and to enhance communication of results among researchers and clinicians, we propose four categories of wear terminology: wear modes refer to the in vivo conditions under which the wear occurred; wear mechanisms refer to fundamental wear processes (adhesion, abrasion, fatigue, and tribochemical reactions); wear damage refers to the resultant changes in the morphology and/or composition of the surfaces; and wear features refer to the specific wear phenomena that are described in terms of the relevant modes, mechanisms, and damage. Clarifying examples are presented, but it is expected that terms will be added to the lexicon as new mechanisms and types of damage are identified. Corrosion refers to electrochemical processes that can remove or add material and thus also generate damage. Corrosion can act alone or may interact with mechanical wear. Examples of corrosion damage are also presented. However, an in-depth discussion of the many types of corrosion and their effects is beyond the scope of the present wear lexicon. PMID:24844814
Wear behaviour of cobalt-chromium-molybdenum alloys used in metal-on-metal hip implants
NASA Astrophysics Data System (ADS)
Varano, Rocco
The influence of carbon (C) content, microstructure, crystallography and mechanical properties on the wear behaviour of metal-on-metal (MM) hip implants made from commercially available cobalt-chromium-molybdenum (CoCrMo) alloys designated as American Society of Testing and Materials (ASTM) grade F1537, F75 and as-cast were studied in this work. The as-received bars of wrought CoCrMo alloys (ASTM F1537 of either about 0.05% or 0.26% C) were each subjected to various heat treatments to develop different microstructures. Pin and plate specimens were fabricated from each bar and were tested against each other using a linear reciprocating pin-on-plate apparatus in 25% by volume bovine serum solution. The applied normal load was 9.81 N and the reciprocating plate had a sinusoidal velocity with an average speed of 26 mm/s. The wear was measured gravimetrically and it was found to be most strongly affected by alloy C content, irrespective of grain size or carbide morphology. More precisely, the wear behaviour was directly correlated to the dissolved C content of the alloys. Increased C in solid-solution coincided with lower volumetric wear since C helps to stabilize the face-centred cubic (FCC) crystal structure thus limiting the amount of strain induced transformation (SIT) to the hexagonal close-packed crystal structure (HCP). Based on the observed surface twinning in and around the contact zone and the potentially detrimental effect of the HCP phase, it was postulated that the MM wear behaviour of CoCrMo alloys in the present study was controlled by a deformation mechanism, rather than corrosion or tribochemical reactions.
Changes in blood ion levels after removal of metal-on-metal hip replacements
Durrani, Salim K; Sampson, Barry; Panetta, Therese; Liddle, Alexander D; Sabah, Shiraz A; Chan, Newton K; Skinner, John A; Hart, Alister J
Background and purpose In patients with metal-on-metal (MoM) hip prostheses, pain and joint effusions may be associated with elevated blood levels of cobalt and chromium ions. Since little is known about the kinetics of metal ion clearance from the body and the rate of resolution of elevated blood ion levels, we examined the time course of cobalt and chromium ion levels after revision of MoM hip replacements. Patients and methods We included 16 patients (13 female) who underwent revision of a painful MoM hip (large diameter, modern bearing) without fracture or infection, and who had a minimum of 4 blood metal ion measurements over an average period of 6.1 (0¢12) months after revision. Results Average blood ion concentrations at the time of revision were 22 ppb for chromium and 43 ppb for cobalt. The change in ion levels after revision surgery varied extensively between patients. In many cases, over the second and third months after revision surgery ion levels decreased to 50% of the values measured at revision. Decay of chromium levels occurred more slowly than decay of cobalt levels, with a 9% lag in return to normal levels. The rate of decay of both metals followed second-order (exponential) kinetics more closely than first-order (linear) kinetics. Interpretation The elimination of cobalt and chromium from the blood of patients who have undergone revision of painful MoM hip arthroplasties follows an exponential decay curve with a half-life of approximately 50 days. Elevated blood levels of cobalt and chromium ions can persist for at least 1 year after revision, especially in patients with high levels of exposure. PMID:24758321
Cross-sectional imaging of metal-on-metal hip arthroplasties
Robinson, Elizabeth; Henckel, Johann; Sabah, Shiraz; Satchithananda, Keshthra; Skinner, John; Hart, Alister
Background and purpose Ś Metal artifact reduction sequence (MARS) MRI is widely advocated for surveillance of metal-on-metal hip arthroplasties (MOM-HAs). However, its use is limited by susceptibility artifact at the prosthesis-bone interface, local availability, patient compliance, and cost (Hayter et al. 2011a). We wanted to determine whether CT is a suitable substitute for MARS MRI in evaluation of the painful MOM-HA. Patients and methods Ś 50 MOM-HA patients (30 female) with unexplained painful prostheses underwent MARS MRI and CT imaging. 2 observers who were blind regarding the clinical data objectively reported the following outcomes: soft tissue lesions (pseudotumors), muscle atrophy, and acetabular and femoral osteolysis. Diagnostic test characteristics were calculated. Results Ś Pseudotumor was diagnosed in 25 of 50 hips by MARS MRI and in 11 of 50 by CT. Pseudotumors were classified as type 1 (n = 2), type 2A (n = 17), type 2B (n = 4), and type 3 (n = 2) by MARS MRI. CT did not permit pseudotumor classification. The sensitivity of CT for diagnosis of pseudotumor was 44% (95% CI: 25¢65). CT had ōslightö agreement with MARS MRI for quantification of muscle atrophy (? = 0.23, CI: 0.16¢0.29; p < 0.01). Osteolysis was identified in 15 of 50 patients by CT. 4 of these lesions were identified by MARS MRI. Interpretation Ś CT was found to be superior to MRI for detection of osteolysis adjacent to MOM-HA, and should be incorporated into diagnostic algorithms. CT was unable to classify and failed to detect many pseudotumors, and it was unreliable for assessment of muscle atrophy. Where MARS MRI is contraindicated or unavailable, CT would be an unsuitable substitute and other modalities such as ultrasound should be considered PMID:25267500
Greater Trochanteric Fragmentation After Failed Metal-on-Metal Hip Arthroplasty.
Panichkul, Phonthakorn; Fricka, Kevin B; Hopper, Robert H; Engh, C Anderson
Adverse reaction to metal debris (ARMD) involving the hip joint has emerged as an important reason for failure and revision among patients with metal-on-metal (MOM) hip arthroplasty. To the authors' knowledge, there are no reports of adverse radiographic sequelae in the greater trochanter subsequent to revision for ARMD. The authors describe clinical and radiographic findings in 2 patients who developed greater trochanteric fragmentation 1 to 2 years after conversion of their failed MOM hips to polyethylene bearings. Both patients had solid pseudotumors with tissue necrosis. Several reports describe various clinical features of ARMD. Although poor outcomes have been demonstrated after some MOM revisions, to the authors' knowledge, no reports document greater trochanter fragmentation in ARMD. The current patients highlight the fact that tissue damage occurring with MOM bearing hips can involve bone in addition to soft tissue even after a pseudotumor has been removed and serum metal levels have decreased to normal levels after revision. Unlike the greater trochanteric fractures historically associated with polyethylene wear and osteolysis, no evidence of bone cysts or lesions was found prior to the fractures and neither fracture healed with conservative treatment. For these 2 patients, the authors believe the tissue necrosis included both soft tissue and bone. The necrotic bone resorbed gradually after removal of the MOM bearing, resulting in bone fragmentation with ongoing symptoms. These patients emphasize and remind us that damage is not only limited to soft tissues, but also includes bone. Surgeons should be aware of this radiographic finding and the associated clinical symptoms. [Orthopedics. 2015; 38(5):e447-e451.]. PMID:25970376
Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations: a follow-up study.
Vendittoli, P-A; Roy, A; Mottard, S; Girard, J; Lusignan, D; Lavigne, M
We have updated our previous randomised controlled trial comparing release of chromium (Cr) and cobalt (Co) ions and included levels of titanium (Ti) ions. We have compared the findings from 28 mm metal-on-metal total hip replacement, performed using titanium CLS/Spotorno femoral components and titanium AlloFit acetabular components with Metasul bearings, with Durom hip resurfacing using a Metasul articulation or bearing and a titanium plasma-sprayed coating for fixation of the acetabular component. Although significantly higher blood ion levels of Cr and Co were observed at three months in the resurfaced group than in total hip replacement, no significant difference was found at two years post-operatively for Cr, 1.58 microg/L and 1.62 microg/L respectively (p = 0.819) and for Co, 0.67 microg/L and 0.94 microg/L respectively (p = 0.207). A steady state was reached at one year in the resurfaced group and after three months in the total hip replacement group. Interestingly, Ti, which is not part of the bearing surfaces with its release resulting from metal corrosion, had significantly elevated ion levels after implantation in both groups. The hip resurfacing group had significantly higher Ti levels than the total hip replacement group for all periods of follow-up. At two years the mean blood levels of Ti ions were 1.87 microg/L in hip resurfacing and and 1.30 microg/L in total hip replacement (p = 0.001). The study confirms even with different bearing diameters and clearances, hip replacement and 28 mm metal-on-metal total hip replacement produced similar Cr and Co metal ion levels in this randomised controlled trial study design, but apart from wear on bearing surfaces, passive corrosion of exposed metallic surfaces is a factor which influences ion concentrations. Ti plasma spray coating the acetabular components for hip resurfacing produces significantly higher release of Ti than Ti grit-blasted surfaces in total hip replacement. PMID:20044673
Blood metal ion testing is an effective screening tool to identify poorly performing metal-on-metal bearing surfaces
Sidaginamale, R. P.; Joyce, T. J.; Lord, J. K.; Jefferson, R.; Blain, P. G.; Nargol, A. V. F.; Langton, D. J.
Objectives The aims of this piece of work were to: 1) record the background concentrations of blood chromium (Cr) and cobalt (Co) concentrations in a large group of subjects; 2) to compare blood/serum Cr and Co concentrations with retrieved metal-on-metal (MoM) hip resurfacings; 3) to examine the distribution of Co and Cr in the serum and whole blood of patients with MoM hip arthroplasties; and 4) to further understand the partitioning of metal ions between the serum and whole blood fractions. Methods A total of 3042 blood samples donated to the local transfusion centre were analysed to record Co and Cr concentrations. Also, 91 hip resurfacing devices from patients who had given pre-revision blood/serum samples for metal ion analysis underwent volumetric wear assessment using a coordinate measuring machine. Linear regression analysis was carried out and receiver operating characteristic curves were constructed to assess the reliability of metal ions to identify abnormally wearing implants. The relationship between serum and whole blood concentrations of Cr and Co in 1048 patients was analysed using Bland-Altman charts. This relationship was further investigated in an in vitro study during which human blood was spiked with trivalent and hexavalent Cr, the serum then separated and the fractions analysed. Results Only one patient in the transfusion group was found to have a blood Co > 2 Ąg/l. Blood/Serum Cr and Co concentrations were reliable indicators of abnormal wear. Blood Co appeared to be the most useful clinical test, with a concentration of 4.5 Ąg/l showing sensitivity and specificity for the detection of abnormal wear of 94% and 95%, respectively. Generated metal ions tended to fill the serum compartment preferentially in vivo and this was replicated in the in vitro study when blood was spiked with trivalent Cr and bivalent Co. Conclusions Blood/serum metal ion concentrations are reliable indicators of abnormal wear processes. Important differences exist however between elements and the blood fraction under study. Future guidelines must take these differences into account. PMID:23836464
A novel technique for the removal of well-fixed cementless, large-diameter metal-on-metal acetabular components.
Olyslaegers, Christophe; Wainwright, Tom; Middleton, Robert G
Removing well-fixed cementless acetabular components can be a challenge for every orthopedic surgeon involved in revision hip arthroplasty. Forceful removal of such components often leads to acetabular bone loss and compromises reimplantation of a new socket. Instruments like the Explant Acetabular Cup Removal System (Zimmer, Warsaw, Ind) are developed to avoid such issues. We report a novel technique, cementing a polyethylene liner inside the uncemented metal-on-metal shell and using systems such as the Explant to safely extract it without the need for matching large-diameter heads. We successfully used this technique on 3 occasions and recommend its use. PMID:18555640
Mid-Term Results of Metal-on-Metal Hip Resurfacing for Treatment of Osteoarthritis Secondary to Developmental Dysplasia of the Hip: A Minimum of 8-Years of Follow-Up
Qu, Yuxing; Jiang, Tao; Zhao, Hong; Gao, Yi; Zheng, Chong; Xu, Jianda
Background Metal-on-metal resurfacing arthroplasty is an attractive alternative to conventional total hip arthroplasty in patients with osteoarthritis secondary to developmental dysplasia of the hip (DDH). The purpose of this study was to assess the mid-term clinical outcome and mid-term survivorship of Metal-on-metal resurfacing arthroplasty in patients suffering from osteoarthritis secondary to DDH. Material/Methods Between May 2003 and Dec. 2005, 15 operations using ASRÖ and 19 using Corin were performed in 29 patients to treat advanced osteoarthritis secondary to DDHs. There were 6 males (20.7%) and 23 females (79.3%), with an average age of 47.2 years (range, 36¢64 years). Clinical and radiographic results were observed. All patients were followed up at the 1st, 2nd, 3rd, 6th, and 12th months after surgery and annually thereafter. Results The overall survival was 88.2% at a minimum follow-up of 8 years, but the survival was 91.2% after excluding the infections as the cause of component loosening and failure. The mean Harris hip score improved from 48.27▒3.13 (range, 14¢71) to 89.63▒3.42 (range, 65¢100) at latest follow-up. The flexion was from 75.14▒8.05░ to 107.21▒9.34. Only 4 failed because of deep infection, femoral neck fracture, and aseptic loosening. Conclusions Metal-on-metal resurfacing arthroplasty showed perfect results at a minimum of 8-years of follow-up in our study, and may be a reasonable option for osteoarthritis secondary to developmental dysplasia of the hip (DDH). PMID:25410054
Chromium-induced diffuse dermatitis with lymph node involvement resulting from Langerhans cell histiocytosis after metal-on-metal hip resurfacing.
Bizzotto, N; Sandri, A; Trivellin, G; Magnan, B; Micheloni, G M; Zam", A; Bernardi, P; Sbarbati, A; Regis, D
Total hip arthroplasty (THA) is a highly effective surgical treatment for severe joint involvement. However, due to the release of metal ions in the blood, the patients who undergo hip replacement with metal-on-metal (MOM) bearings may develop signs of allergic skin disease. We report a case of a 60-year-old man who had received MOM hip resurfacing 5Āyears earlier for osteoarthritis. He presented with a 3-year history of diffuse dermatitis that did not respond to antihistamines and corticosteroids and also had elevated serum levels of chromium and cobalt. A patch test revealed chromium-sulfate hypersensitivity. A skin biopsy showed nonspecific perivascular lymphocytic infiltrate associated with histiocytes. A biopsy of an inguinal lymph node demonstrated large aggregates of Langerhans cells, suggesting type IV delayed-type hypersensitivity. The prosthesis was replaced using ceramic-on-ceramic bearings and the dermatitis resolved after 3Āmonths. The lymph nodes decreased in volume and the serum chromium levels normalized within 24Āmonths of revision surgery. The high levels of serum ions associated with the metal debris from MOM-THAs may induce sensitization and type IV hypersensitivity reactions. Replacing the prosthesis using alternative coupling surfaces is the only approach that has the capacity to resolve these symptoms. Physicians who are not familiar with this issue may misdiagnose systemic symptoms and provide inadequate treatment. PMID:25385406
Is Increased Modularity Associated With Increased Fretting and Corrosion Damage in Metal-On-Metal Total Hip Arthroplasty Devices?
Higgs, Genymphas B.; Hanzlik, Josa A.; MacDonald, Daniel W.; Gilbert, Jeremy L.; Rimnac, Clare M.; Kurtz, Steven M.
This retrieval study documents taper damage at modular interfaces in retrieved MOM THA systems and investigates if increased modularity is associated with increased fretting and corrosion. One hundred thirty-four (134) heads and 60 stems (41 modular necks) of 8 different bearing designs (5 manufacturers) were analyzed. Damage at the shell¢liner interface of 18 modular CoCr acetabular liners and the corresponding 11 acetabular shells was also evaluated. The results of this study support the hypothesis that fretting and corrosion damage occurs at a variety of modular component interfaces in contemporary MOM THAs. We also found that modularity of the femoral stem was associated with increased damage at the head. An analysis of component and patient variables revealed that dissimilar alloy pairing, larger head sizes, increased medio-lateral offsets and longer neck moment arms were all associated with increased taper damage at the modular interfaces. PMID:23910820
Clinical Usefulness of SPECT-CT in Patients with an Unexplained Pain in Metal on Metal (MOM) Total Hip Arthroplasty.
Berber, Reshid; Henckel, Johann; Khoo, Michael; Wan, Simon; Hua, Jia; Skinner, John; Hart, Alister
SPECT-CT is increasingly used to assess painful knee arthroplasties. The aim of this study was to evaluate the clinical usefulness of SPECT-CT in unexplained painful MOM hip arthroplasty. We compared the diagnosis and management plan for 19 prosthetic MOM hips in 15 subjects with unexplained pain before and after SPECT-CT. SPECT-CT changed the management decision in 13 (68%) subjects, Chi-Square=5.49, P=0.24. In 6 subjects (32%) pain remained unexplained however the result reassured the surgeon to continue with non-operative management. SPECT-CT should be reserved as a specialist test to help identify possible causes of pain where conventional investigations have failed. It can help reassure surgeons making management decisions for patients with unexplained pain following MOM hip arthroplasty. PMID:25583682
Clarke, S G; Phillips, A T M; Bull, A M J; Cobb, J P
The impact of anatomical variation and surgical error on excessive wear and loosening of the acetabular component of large diameter metal on metal hip arthroplasties was measured using a multi-factorial analysis through 112 different simulations. Each surgical scenario was subject to eight different daily loading activities using finite element analysis. Excessive wear appears to be predominantly dependent on cup orientation, with inclination error having a higher influence than version error, according to the study findings. Acetabular cup loosening, as inferred from initial implant stability, appears to depend predominantly on factors concerning the area of cup-bone contact, specifically the level of cup seating achieved and the individual patientÆs anatomy. The extent of press fit obtained at time of surgery did not appear to influence either mechanism of failure in this study. PMID:22513086
MRI findings following metal on metal hip arthroplasty and their relationship with metal ion levels and acetabular inclination angles.
Fox, Ciara M; Bergin, Karen M; Kelly, Gabrielle E; McCoy, Gerry F; Ryan, Anthony G; Quinlan, John F
Following the global recall of all ASR metal on metal hip products, our aim was to correlate MRI findings with acetabular inclination angles and metal ion levels in patients with these implants. Both cobalt and chromium levels were significantly higher in the presence of a periprosthetic fluid collection. There was no association between the presence of a periprosthetic mass, bone marrow oedema, trochanteric bursitis or greater levels of abductor muscle destruction for cobalt or chromium. There was no association between the level of periprosthetic tissue reaction and the acetabular inclination angle with any of the pathologies identified on MRI. The relationship between MRI pathology, metal ion levels and acetabular inclination angles in patients with ASR implants remains unclear adding to the complexity of managing patients. PMID:24793890
Wear of surface-engineered metal-on-metal bearings for hip prostheses under adverse conditions with the head loading on the rim of the cup.
Leslie, Ian; Williams, Sophie; Isaac, Graham; Hatto, Peter; Ingham, Eileen; Fisher, John
Clinical studies have found high wear rates, elevated ion levels and high revision rates of large-diameter metal-on-metal surface replacement bearings in some patients, which have been associated with edge loading of the head on the rim of the cup. We have simulated increased wear and ion levels in metal-on-metal bearings in vitro by introducing variations in translational and rotational positioning of the components, which reproduces stripe wear on the femoral head, cup rim wear and clinically relevant large as well as small wear particles. There is interest in technologies such as surface engineering, which might reduce metal wear and the release of wear particles and ions. Reduced wear with surface-engineered surface replacements compared to metal-on-metal controls has been reported under standard walking conditions with correctly aligned and concentric components. In this in vitro study, the wear of chromium nitride surface-engineered metal-on-metal bearings under conditions of microseparation associated with translational and rotational malpositioning of the components was investigated and the results were compared with a previously reported study of metal-on-metal bearings under the same conditions. Simulations were conducted using our unique hip simulation microseparation methodologies, which reproduce accelerated wear in metal-on-metal bearings and have previously been clinically validated with ceramic-on-ceramic bearings. Four of the six surface-engineered bearings had evidence of head contact on the rim of the cup, which produced stripe wear on the femoral head. Four of the six surface-engineered bearings (two without stripe and two with stripe wear) had lower wear than the previously reported high wearing metal-on-metal bearings. At 2 million cycles, two of the surface-engineered bearings had substantially increased wear rates, four times higher than the high wear rates previously reported for metal-on-metal bearings under the same conditions. There was wear through and cohesive failure of the thick atomic emission physical vapour deposition (AEPVD) chromium nitride (CrN) coating. At this point, the study was stopped to investigate the failure mode. This study highlights the need to pre-clinically investigate the tribology of new bearings under a wide set of clinical conditions as demonstrated by our stratified approach for enhanced reliability (SAFER) simulation methods. In adopting this SAFER approach to pre-clinical simulation testing of new bearings, it is important to communicate the failures as well as successes of technologies arising from the research, in order that the wider community can benefit from the analysis of the pre-clinical failure modes. PMID:23637209
Auditory and Visual Health after Ten Years of Exposure to Metal-on-Metal Hip Prostheses: A Cross-Sectional Study Follow Up
Prentice, Jennifer R.; Blackwell, Christopher S.; Raoof, Naz; Bacon, Paul; Ray, Jaydip; Hickman, Simon J.; Wilkinson, J. Mark
Case reports of patients with mal-functioning metal-on-metal hip replacement (MoMHR) prostheses suggest an association of elevated circulating metal levels with visual and auditory dysfunction. However, it is unknown if this is a cumulative exposure effect and the impact of prolonged low level exposure, relevant to the majority of patients with a well-functioning prosthesis, has not been studied. Twenty four male patients with a well-functioning MoMHR and an age and time since surgery matched group of 24 male patients with conventional total hip arthroplasty (THA) underwent clinical and electrophysiological assessment of their visual and auditory health at a mean of ten years after surgery. Median circulating cobalt and chromium concentrations were higher in patients after MoMHR versus those with THA (P<0.0001), but were within the Medicines and Healthcare Products Regulatory Agency (UK) investigation threshold. Subjective auditory tests including pure tone audiometric and speech discrimination findings were similar between groups (P>0.05). Objective assessments, including amplitude and signal-to-noise ratio of transient evoked and distortion product oto-acoustic emissions (TEOAE and DPOAE, respectively), were similar for all the frequencies tested (P>0.05). Auditory brainstem responses (ABR) and cortical evoked response audiometry (ACR) were also similar between groups (P>0.05). Ophthalmological evaluations, including self-reported visual function by visual functioning questionnaire, as well as binocular low contrast visual acuity and colour vision were similar between groups (P>0.05). Retinal nerve fibre layer thickness and macular volume measured by optical coherence tomography were also similar between groups (P>0.05). In the presence of moderately elevated metal levels associated with well-functioning implants, MoMHR exposure does not associate with clinically demonstrable visual or auditory dysfunction. PMID:24621561
Early failure of the Durom prosthesis in metal-on-metal hip resurfacing in Chinese patients.
Li, Jia; He, Chongru; Li, Dahe; Zheng, Wei; Liu, Denghui; Xu, Weidong
Hip resurfacing (HR) is being used increasingly as an alterative to total hip arthroplasty in osteonecrosis (ON) and ankylosing spondylitis (AS) of the hip. We performed 141 consecutive HR arthroplasties in 111 patients comprising 3 etiology groups: ON, AS, and osteoarthritis (OA). After retrospective study of retrieved components, we hypothesized that the main reason for revision was femoral loosening in the ON group (4 of 46 hips; 8.7%) and femoral-neck fracture in the AS group (3 of 58 hips; 5.2%). Necrotic areas were seen on femoral heads retrieved from patients with femoral loosening, whereas femoral heads were fixed tightly to components in patients with femoral-neck fractures. Etiology may be an important risk factor for postoperative complications. PMID:23831082
Comparison of in vivo and simulator-retrieved metal-on-metal cervical disc replacements
Kurtz, Steven M.; Ciccarelli, Lauren; Harper, Megan L.; Siskey, Ryan; Shorez, Jacob; Chan, Frank W.
Background Cervical disc arthroplasty is regarded as a promising treatment for myelopathy and radiculopathy as an alternative to cervical spine fusion. On the basis of 2-year clinical data for the PRESTIGE« Cervical Disc (Medtronic, Memphis, Tennessee), the Food and Drug Administration recommended conditional approval in September 2006 and final approval in July 2007; however, relatively little is known about its wear and damage modes in vivo. The main objective was to analyze the tribological findings of the PRESTIGE« Cervical Disc. This study characterized the in vivo wear patterns of retrieved cervical discs and tested the hypothesis that the total disc replacements exhibited similar surface morphology and wear patterns in vitro as in vivo. Methods Ten explanted total disc replacements (PRESTIGE«, PRESTIGE« I, and PRESTIGE« II) from 10 patients retrieved after a mean of 1.8 years (range, 0.3¢4.1 years) were analyzed. Wear testing included coupled lateral bending ( ▒4.7░) and axial rotation ( ▒3.8░) with a 49 N axial load for 5 million cycles followed by 10 million cycles of flexion-extension ( ▒9.7░) with 148 N. Implant surfaces were characterized by the use of white-light interferometry, scanning electron microscopy, and energy dispersive spectroscopy. Results The explants generally exhibited a slightly discolored, elliptic wear region of varying dimension centered in the bearing center, with the long axis oriented in the medial-lateral direction. Abrasive wear was the dominant in vivo wear mechanism, with microscopic scratches generally oriented in the medial-lateral direction. Wear testing resulted in severe abrasive wear in a curvilinear fashion oriented primarily in the medial-lateral direction. All retrievals showed evidence of an abrasive wear mechanism. Conclusions This study documented important similarity between the wear mechanisms of components tested in vitro and explanted PRESTIGE« Cervical Discs; however, the severity of wear was much greater during the in vitro test compared with the retrievals. PMID:25694884
Admetal-induced substrate surface restructuring during metal-on-metal electrochemical deposition studied by in situ scanning tunneling microscopy
NASA Astrophysics Data System (ADS)
Maroun, F.; Morin, S.; Lachenwitzer, A.; Magnussen, O. M.; Behm, R. J.
Based on time-dependent in situ scanning tunneling microscopy (STM) studies, we demonstrate that for Ni on Ag(111) and Ru on Au(111), electrochemical metal-on-metal deposition can result in pronounced substrate surface restructuring. For Ni/Ag(111), we observe that at low deposition flux and low coverage, Ni submonolayer islands at steps are partly embedded in the Ag terraces, whereas at higher deposition flux and higher coverage, substrate restructuring results in the formation of monolayer bays in the Ag terraces. We suggest that this restructuring process proceeds predominantly via step edge diffusion of Ag atoms. For Ru/Au(111), the formation of fjords and monolayer holes in the Au terraces is observed at low and high Ru coverage, respectively. The importance of the Au surface mobility for the restructuring process is demonstrated by comparing experiments in H 2SO 4 and HCl solutions, in which Au exhibits strongly different surface mobilities. For this system, restructuring involves Au diffusion along Au steps, Au atom detachment from the Au steps, and upward exchange diffusion. According to these observations and their comparison with similar findings for vacuum deposition, we conclude that this restructuring requires (i) a high substrate surface mobility and (ii) a stronger bonding of substrate atoms to deposit islands than to the substrate.
Chromium and cobalt ion concentrations in blood and serum following various types of metal-on-metal hip arthroplasties
Background and purpose Widely different metal ion concentrations in blood and serum have been reported with metal-on-metal (MoM) implants. We reviewed the literature on blood and serum ion concentrations of chromium (Cr) and cobalt (Co) following various MoM hip arthroplasties. Methods Studies were searched for in the Medline database, Embase, and the Cochrane Database of Systematic Reviews. Highest mean or median ion concentrations of Cr and Co after a minimum of 1 year of follow-up were extracted and grouped according to sample- and articulation type, and average values were calculated. Results 43 studies were included and 16 different MoM implants were identified. For the different types of bearings, average ion concentrations and range were calculated from the mean or median ion concentration. The average Cr concentration ranged between 0.5 and 2.5 ?g/L in blood and between 0.8 and 5.1 ?g/L in serum. For Co, the range was 0.7¢3.4 ?g/L in blood and 0.3¢7.5 ?g/L in serum. Interpretation When the average blood ion concentrations calculated for the different implants, together with the concentrations measured in the individual studies, were compared with the upper acceptable limit for Cr and Co in blood, no clear pattern was recognized. Furthermore, we were unable to detect any clear difference in ion concentrations between different types of implants (THA and resurfacing). PMID:23594249
A hip simulator study of metal-on-metal hip joint device using acetabular cups with different fixation surface conditions.
Li, C X; Hussain, A; Kamali, A
In vitro wear data for hip joint devices reported in the literature vary in a wide range from one simulator study to another sometimes for the same type of device tested under identical physiological testing conditions. We hypothesized that non-bearing surface condition of the testing components could be an important factor affecting the simulator wear results. To confirm this hypothesis, fifteen 50 mm metal-on-metal hip resurfacing devices with identical bearing specifications were tested in a ProSim hip wear simulator for 5 million cycles. The heads were standard Birmingham Hip Resurfacing (BHR) heads; whilst the pairing acetabular cups were identical to the standard BHR cup except their different back surface conditions, including: (a) off-the-shelf products after removing the hydroxyapatite (HA) coating; (b) semi-finished products without HA coating; and (c) purposely-made cups without cast-in beads and HA coating. Results showed that the different back surfaces of the cups used indeed caused significantly large variations in the gravimetrically measured wear loss. We postulated that materials loss from the non-bearing surface of the testing components could contribute to the gravimetrically measured wear loss during a wear simulator test both directly and indirectly. The results presented in this paper pertain to In vitro wear simulator study and have little clinical relevance to the performance of any implant in vivo. PMID:22070025
Good sensitivity and specificity of ultrasound for detecting pseudotumors in 83 failed metal-on-metal hip replacements
Lainiala, Olli; Elo, Petra; Reito, Aleksi; Pajamõki, Jorma; Puolakka, Timo; Eskelinen, Antti
Background and purpose Ultrasound is used for imaging of pseudotumors associated with metal-on-metal (MoM) hips. Ultrasound has been compared with magnetic resonance imaging, but to date there have been no studies comparing ultrasound findings and revision findings. Methods We evaluated the sensitivity and specificity of preoperative ultrasound for detecting pseudotumors in 82 patients with MoM hip replacement (82 hips). Ultrasound examinations were performed by 1 of 3 musculoskeletal radiologists, and pseudotumors seen by ultrasound were retrospectively classified as fluid-filled, mixed-type, or solid. Findings at revision surgery were retrieved from surgical notes and graded according to the same system as used for ultrasound findings. Results Ultrasound had a sensitivity of 83% (95% CI: 63¢93) and a specificity of 92% (CI: 82¢96) for detecting trochanteric region pseudotumors, and a sensitivity of 79% (CI: 62¢89) and a specificity of 94% (CI: 83¢98) for detecting iliopsoas-region pseudotumors. Type misclassification of pseudotumors found at revision occurred in 8 of 23 hips in the trochanteric region and in 19 of 33 hips in the iliopsoas region. Interpretation Despite the discrepancy in type classification between ultrasound and revision findings, the presence of pseudotumors was predicted well with ultrasound in our cohort of failed MoM hip replacements. PMID:25582840
Metal ion levels and revision rates in metal-on-metal hip resurfacing arthroplasty: a comparative study.
Robinson, Patrick G; Wilkinson, Andrew J; Meek, Robert M D
Metal-on-metal (MoM) bearings in hip surgery are related to increased blood levels of metal ions. The nature of the relationship between ion levels and failure is still not fully understood. This study compares three cohorts of patients, 120 patients in each cohort, treated with a hip resurfacing arthroplasty, grouped by brand and diameter of femoral component on average four years postoperatively: Birmingham Hip Resurfacing ?50 mm, Durom resurfacing ?50 mm and Durom resurfacing <50 mm. The median blood ion levels of cobalt and chromium were significantly lower in the cohort with the large Durom resurfacing than the other two cohorts (P<0.05). The large BHR and large Durom HRA had revision rates of 3.3%. The small Durom HRA had a revision rate of 8.3%. Elevated blood ion levels can indicate a failing MoM bearing. The large BHR and large Durom HRA have similar revision rates yet the large Durom HRA had significantly lower metal ion levels. When similar ion levels were reported for BHR and small Durom the latter had significantly higher revision rates. This suggests ion levels do not absolutely predict the rate of HRA failure. Since MoM generation of metal ions is not the sole reason of failure, regular clinical and radiographic follow-up should also be in place for patients with these joints. PMID:24500833
Validation of primary metal-on-metal hip arthroplasties on the National Joint Registry for England, Wales and Northern Ireland using data from the London Implant Retrieval Centre: a study using the NJR dataset.
Sabah, S A; Henckel, J; Cook, E; Whittaker, R; Hothi, H; Pappas, Y; Blunn, G; Skinner, J A; Hart, A J
Arthroplasty registries are important for the surveillance of joint replacements and the evaluation of outcome. Independent validation of registry data ensures high quality. The ability for orthopaedic implant retrieval centres to validate registry data is not known. We analysed data from the National Joint Registry for England, Wales and Northern Ireland (NJR) for primary metal-on-metal hip arthroplasties performed between 2003 and 2013. Records were linked to the London Implant Retrieval Centre (RC) for validation. A total of 67,045 procedures on the NJR and 782 revised pairs of components from the RC were included. We were able to link 476 procedures (60.9%) recorded with the RC to the NJR successfully. However, 306 procedures (39.1%) could not be linked. The outcome recorded by the NJR (as either revised, unrevised or death) for a primary procedure was incorrect in 79 linked cases (16.6%). The rate of registry-retrieval linkage and correct assignment of outcome code improved over time. The rates of error for component reference numbers on the NJR were as follows: femoral head category number 14/229 (5.0%); femoral head batch number 13/232 (5.3%); acetabular component category number 2/293 (0.7%) and acetabular component batch number 24/347 (6.5%). Registry-retrieval linkage provided a novel means for the validation of data, particularly for component fields. This study suggests that NJR reports may underestimate rates of revision for many types of metal-on-metal hip replacement. This is topical given the increasing scope for NJR data. We recommend a system for continuous independent evaluation of the quality and validity of NJR data. PMID:25568407
Activation of Noble Metals on Metal-Carbide Surfaces: Novel Catalysts for CO Oxidation, Desulfurization and Hydrogenation Reactions
Rodriguez J. A.; Illas, F.
This perspective article focuses on the physical and chemical properties of highly active catalysts for CO oxidation, desulfurization and hydrogenation reactions generated by depositing noble metals on metal-carbide surfaces. To rationalize structure-reactivity relationships for these novel catalysts, well-defined systems are required. High-resolution photoemission, scanning tunneling microscopy (STM) and first-principles periodic density-functional (DF) calculations have been used to study the interaction of metals of Groups 9, 10 and 11 with MC(001) (M = Ti, Zr, V, Mo) surfaces. DF calculations give adsorption energies that range from 2 eV (Cu, Ag, Au) to 6 eV (Co, Rh, Ir). STM images show that Au, Cu, Ni and Pt grow on the carbide substrates forming two-dimensional islands at very low coverage, and three-dimensional islands at medium and large coverages. In many systems, the results of DF calculations point to the preferential formation of admetal-C bonds with significant electronic perturbations in the admetal. TiC(001) and ZrC(001) transfer some electron density to the admetals facilitating bonding of the adatom with electron-acceptor molecules (CO, O{sub 2}, C{sub 2}H{sub 4}, SO{sub 2}, thiophene, etc.). For example, the Cu/TiC(001) and Au/TiC(001) systems are able to cleave both S-O bonds of SO{sub 2} at a temperature as low as 150 K, displaying a reactivity much larger than that of TiC(001) or extended surfaces of bulk copper and gold. At temperatures below 200 K, Au/TiC is able to dissociate O{sub 2} and perform the 2CO + O{sub 2} {yields} 2CO{sub 2} reaction. Furthermore, in spite of the very poor hydrodesulfurization performance of TiC(001) or Au(111), a Au/TiC(001) surface displays an activity for the hydrodesulfurization of thiophene higher than that of conventional Ni/MoS{sub x} catalysts. In general, the Au/TiC system is more chemically active than systems generated by depositing Au nanoparticles on oxide surfaces. Thus, metal carbides are excellent supports for enhancing the chemical reactivity of noble metals.
Optimal acetabular component orientation estimated using edge-loading and impingement risk in patients with metal-on-metal hip resurfacing arthroplasty.
Mellon, Stephen J; Grammatopoulos, George; Andersen, Michael S; Pandit, Hemant G; Gill, Harinderjit S; Murray, David W
Edge-loading in patients with metal-on-metal resurfaced hips can cause high serum metal ion levels, the development of soft-tissue reactions local to the joint called pseudotumours and ultimately, failure of the implant. Primary edge-loading is where contact between the femoral and acetabular components occurs at the edge/rim of the acetabular component whereas impingement of the femoral neck on the acetabular component's edge causes secondary or contrecoup edge-loading. Although the relationship between the orientation of the acetabular component and primary edge-loading has been identified, the contribution of acetabular component orientation to impingement and secondary edge-loading is less clear. Our aim was to estimate the optimal acetabular component orientation for 16 metal-on-metal hip resurfacing arthroplasty (MoMHRA) subjects with known serum metal ion levels. Data from motion analysis, subject-specific musculoskeletal modelling and Computed Tomography (CT) measurements were used to calculate the dynamic contact patch to rim (CPR) distance and impingement risk for 3416 different acetabular component orientations during gait, sit-to-stand, stair descent and static standing. For each subject, safe zones free from impingement and edge-loading (CPR <10%) were defined and, consequently, an optimal acetabular component orientation was determined (mean inclination 39.7░ (SD 6.6░) mean anteversion 14.9░ (SD 9.0░)). The results of this study suggest that the optimal acetabular component orientation can be determined from a patient's motion and anatomy. However, 'safe' zones of acetabular component orientation associated with reduced risk of dislocation and pseudotumour are also associated with a reduced risk of edge-loading and impingement. PMID:25482661
Is increased modularity associated with increased fretting and corrosion damage in metal-on-metal total hip arthroplasty devices?: a retrieval study.
Higgs, Genymphas B; Hanzlik, Josa A; MacDonald, Daniel W; Gilbert, Jeremy L; Rimnac, Clare M; Kurtz, Steven M
This retrieval study documents taper damage at modular interfaces in retrieved MOM THA systems and investigates if increased modularity is associated with increased fretting and corrosion. One hundred thirty-four (134) heads and 60 stems (41 modular necks) of 8 different bearing designs (5 manufacturers) were analyzed. Damage at the shell-liner interface of 18 modular CoCr acetabular liners and the corresponding 11 acetabular shells was also evaluated. The results of this study support the hypothesis that fretting and corrosion damage occurs at a variety of modular component interfaces in contemporary MOM THAs. We also found that modularity of the femoral stem was associated with increased damage at the head. An analysis of component and patient variables revealed that dissimilar alloy pairing, larger head sizes, increased medio-lateral offsets and longer neck moment arms were all associated with increased taper damage at the modular interfaces. PMID:23910820
Metal on metal oxide nanowire Co-catalyzed Si photocathode for solar water splitting This article has been downloaded from IOPscience. Please scroll down to see the full text article.
Wang, Deli
for effective photoelectrochemical cells and hydrogen generation. Both ZnO nanocrystalline thin films appear in colour only in the online journal) 1. Introduction After the idea of photoelectrolysis (solarMetal on metal oxide nanowire Co-catalyzed Si photocathode for solar water splitting This article
Chromium and cobalt ion release following the Durom high carbon content, forged metal-on-metal surface replacement of the hip.
Vendittoli, P-A; Mottard, S; Roy, A G; Dupont, C; Lavigne, M
We evaluated the concentrations of chromium and cobalt ions in blood after metal-on-metal surface replacement arthroplasty using a wrought-forged, high carbon content chromium-cobalt alloy implant in 64 patients. At one year, mean whole blood ion levels were 1.61 microg/L (0.4 to 5.5) for chromium and 0.67 microg/L (0.23 to 2.09) for cobalt. The pre-operative ion levels, component size, female gender and the inclination of the acetabular component were inversely proportional to the values of chromium and/or cobalt ions at one year postoperatively. Other factors, such as age and level of activity, did not correlate with the levels of metal ions. We found that the levels of the ions in the serum were 1.39 and 1.37 times higher for chromium and cobalt respectively than those in the whole blood. The levels of metal ions obtained may be specific to the hip resurfacing implant and reflect its manufacturing process. PMID:17463109
The relationship between the angle of version and rate of wear of retrieved metal-on-metal resurfacings: a prospective, CT-based study.
Hart, A J; Ilo, K; Underwood, R; Cann, P; Henckel, J; Lewis, A; Cobb, J; Skinner, J
We measured the orientation of the acetabular and femoral components in 45 patients (33 men, 12 women) with a mean age of 53.4 years (30 to 74) who had undergone revision of metal-on-metal hip resurfacings. Three-dimensional CT was used to measure the inclination and version of the acetabular component, femoral version and the horizontal femoral offset, and the linear wear of the removed acetabular components was measured using a roundness machine. We found that acetabular version and combined version of the acetabular and femoral components were weakly positively correlated with the rate of wear. The acetabular inclination angle was strongly positively correlated with the rate of wear. Femoral version was weakly negatively correlated with the rate of wear. Application of a threshold of > 5 ?m/year for the rate of wear in order to separate the revisions into low or high wearing groups showed that more high wearing components were implanted outside Lewinnek's safe zone, but that this was mainly due to the inclination of the acetabular component, which was the only parameter that significantly differed between the groups. We were unable to show that excess version of the acetabular component alone or combined with femoral version was associated with an increase in the rate of wear based on our assessment of version using CT. PMID:21357951
Differential distribution of cobalt, chromium, and nickel between whole blood, plasma and urine in patients after metal-on-metal (MoM) hip arthroplasty.
Newton, Ashley W; Ranganath, Lakshminarayan; Armstrong, Catherine; Peter, Viju; Roberts, Norman B
Evidence shows that raised cobalt (Co), chromium (Cr), and nickel (Ni) whole blood concentrations correlate with poor device outcome in patients following metal-on-metal (MoM) hip arthroplasty. To understand the local and systemic pathological effects of these raised metal concentrations it is important to define their distribution between whole blood, plasma, and urine. The metals were measured by Inductively Coupled Plasma Mass Spectrometry (ICPMS). Two hundred and five plasma, 199 whole blood, and 24 sets of urine samples were analyzed from 202 patients with Co-Cr alloy MoM hip prostheses implanted between 8 months to 12 years (mean 6.0 years) prior to analysis. Plasma Co (median 39.1 nmol/L) showed significantly positive 1:1 correlation with whole blood Co (median 45.9 nmol/L; R(2) ?= 0.98, p < 0.001, slope = 1.0). Plasma Cr (median 53.8 nmol/L) and whole blood Cr (median 40.3 nmol/L) were also correlated; however, concentrations were significantly higher in plasma indicating relatively little blood cell uptake (R(2) ?= 0.96, p < 0.001, slope = 1.6). Urinary Co was up to threefold higher than Cr (median 334.0 vs. 97.3 nmol/L respectively). Nickel concentrations in whole blood, plasma, and urine were low relative to Co and Cr. The analysis shows fundamental differences in the physiological handling of these metals: Co is distributed approximately equally between blood cells and plasma, whereas Cr is mainly in plasma, despite which, Cr had far less renal excretion than Co. PMID:22447496
Comparison of extracapsular pseudotumors seen in magnetic resonance imaging and in revision surgery of 167 failed metal-on-metal hip replacements
Lainiala, Olli; Elo, Petra; Reito, Aleksi; Pajamõki, Jorma; Puolakka, Timo
Background and purpose Magnetic resonance imaging (MRI) is important for detecting extracapsular pseudotumors, but there is little information on the accuracy of MRI and appropriate intervals for repeated imaging. We evaluated the sensitivity and specificity of MRI for detecting pseudotumors in 155 patients (167 hips) with metal-on-metal (MoM) hip arthroplasties that failed due to adverse reactions to metal debris (ARMD). Methods Preoperative MRIs were performed with two 1.5 T MRI scanners and graded by a senior musculoskeletal radiologist using a previously described MRI pseudotumor grading system. Revision findings were retrieved from surgical notes, and pseudotumors were retrospectively graded as fluid-filled, mixed-type, or solid. Results The sensitivity of MRI was 71% and the specificity was 87% for detecting extracapsular pseudotumors. The sensitivity was 88% (95% CI: 70¢96) when MRI was performed less than 3 months before the revision surgery. Interestingly, when the time that elapsed between MRI and revision was more than 1 year, the sensitivity calculated was only 29% (95% CI: 14¢56). Comparison between MRI and revision classifications gave moderate agreement (CohenÆs kappa = 0.4). Interpretation A recent MRI predicts the presence of a pseudotumor well, but there is more discrepancy when the MRI examination is over a year old, most likely due to the formation of new pseudotumors. 1 year could be a justifiable limit for considering a new MRI if development of ARMD is suspected. MRI images over a year old should not be used in decision making or in planning of revision surgery for MoM hips. PMID:24954485
An in vitro study of the reduction in wear of metal-on-metal hip prostheses using surface-engineered femoral heads.
Fisher, J; Hu, X Q; Tipper, J L; Stewart, T D; Williams, S; Stone, M H; Davies, C; Hatto, P; Bolton, J; Riley, M; Hardaker, C; Isaac, G H; Berry, G; Ingham, E
Although the wear of existing metal-on-metal (MOM) hip prostheses (1 mm3/10(6) cycles) is much lower than the more widely used polyethylene-on-metal bearings, there are concerns about the toxicity of metal wear particles and elevated metal ion levels, both locally and systemically, in the human body. The aim of this study was to investigate the possibility of reducing the volume of wear, the concentration of metal debris and the level of metal ion release through using surface-engineered femoral heads. Three thick (8-12 microm) coatings (TiN, CrN and CrCN) and one thin (2 microm) coating (diamond-like carbon, DLC), were evaluated on the femoral heads when articulating against high carbon content cobalt-chromium alloy acetabular inserts (HC CoCrMo) and compared with a clinically used MOM cobalt-chromium alloy bearing couple using a physiological anatomical hip joint simulator (Leeds Mark II). This study showed that CrN, CrCN and DLC coatings produced substantially lower wear volumes for both the coated femoral heads and the HC CoCrMo inserts. The TiN coating itself had little wear, but it caused relatively high wear of the HC CoCrMo inserts compared with the other coatings. The majority of the wear debris for all half-coated couples comprised small, 30 nm or less, CoCrMo metal particles. The Co, Cr and Mo ion concentrations released from the bearing couples of CrN-, CrCN- and DLC-coated heads articulating against HC CoCrMo inserts were at least 7 times lower than those released from the clinical MOM prostheses. These surface-engineered femoral heads articulating on HC CoCrMo acetabular inserts produced significantly lower wear volumes and rates, and hence lower volumetric concentrations of wear particles, compared with the clinical MOM prosthesis. The substantially lower ion concentration released by these surface-engineered components provides important evidence to support the clinical application of this technology. PMID:12206518
Toxicology of wear particles of cobalt-chromium alloy metal-on-metal hip implants Part II: Importance of physicochemical properties and dose in animal and in vitro studies as a basis for risk assessment.
Madl, Amy K; Kovochich, Michael; Liong, Monty; Finley, Brent L; Paustenbach, Dennis J; Oberd÷rster, G³nter
The objective of the Part II analysis was to evaluate animal and in vitro toxicology studies of CoCr particles with respect to their physicochemistry and dose relevance to metal-on-metal (MoM) implant patients as derived from Part I. In the various toxicology studies, physicochemical characteristics were infrequently considered and administered doses were orders of magnitude higher than what occurs in patients. Co was consistently shown to rapidly release from CoCr particles for distribution and elimination from the body. CoCr micron sized particles appear more biopersistent in vivo resulting in inflammatory responses that are not seen with similar mass concentrations of nanoparticles. We conclude, that in an attempt to obtain data for a complete risk assessment, future studies need to focus on physicochemical characteristics of nano and micron sized particles and on doses and dose metrics relevant to those generated in patients or in properly conducted hip simulator studies. PMID:25735266
NASA Astrophysics Data System (ADS)
Liou, N. S.; Prakash, V.
In the present study plate impact pressure shear friction experiments are conducted to provide insight into time-resolved dry sliding characteristics of frictional interfaces at normal pressures of approximately 1.5 to 2 GPa, interfacial slip speeds of approximately 100 m/s and interfacial temperatures as high as 800 degrees centigrade. These experiments represent a significant improvement over conventional dynamic friction experiments by allowing the interpretation of critical friction parameters by using the framework of one-dimensional plane wave analysis. The experiments are conducted on Carpentor Hampden tool-steel/7075-T6 Al and tool-steel/Ti6Al4V tribo pairs. By an appropriate selection of the flyer and target plate thickness, the frictional state at the tribo-pair interface is varied by subjecting the interface to step changes in normal pressure and the applied shear stress. The results of these experiments provide some new insights into the evolution of interfacial sliding resistance as a function of accumulated slip, slip velocity, interfacial normal pressures and temperatures.
CoCr wear particles generated from CoCr alloy metal-on-metal hip replacements, and cobalt ions stimulate apoptosis and expression of general toxicology-related genes in monocyte-like U937 cells.
Posada, Olga M; Gilmour, Denise; Tate, Rothwelle J; Grant, M Helen
Cobalt-chromium (CoCr) particles in the nanometre size range and their concomitant release of Co and Cr ions into the patients' circulation are produced by wear at the articulating surfaces of metal-on-metal (MoM) implants. This process is associated with inflammation, bone loss and implant loosening and led to the withdrawal from the market of the DePuy ASRÖ MoM hip replacements in 2010. Ions released from CoCr particles derived from a resurfacing implant in vitro and their subsequent cellular up-take were measured by ICP-MS. Moreover, the ability of such metal debris and Co ions to induce both apoptosis was evaluated with both FACS and immunoblotting. qRT-PCR was used to assess the effects on the expression of lymphotoxin alpha (LTA), BCL2-associated athanogene (BAG1), nitric oxide synthase 2 inducible (NOS2), FBJ murine osteosarcoma viral oncogene homolog (FOS), growth arrest and DNA-damage-inducible alpha (GADD45A). ICP-MS showed that the wear debris released significant (p<0.05) amounts of Co and Cr ions into the culture medium, and significant (p<0.05) cellular uptake of both ions. There was also an increase (p<0.05) in apoptosis after a 48h exposure to wear debris. Analysis of qRT-PCR results found significant up-regulation (p<0.05) particularly of NOS2 and BAG1 in Co pre-treated cells which were subsequently exposed to Co ions+debris. Metal debris was more effective as an inducer of apoptosis and gene expression when cells had been pre-treated with Co ions. This suggests that if a patient receives sequential bilateral CoCr implants, the second implant may be more likely to produce adverse effects than the first one. PMID:25281833
Effect of femoral head size on risk of revision for dislocation after total hip arthroplasty
Kostensalo, Inari; Junnila, Mika; Virolainen, Petri; Remes, Ville; Matilainen, Markus; Vahlberg, Tero; Pulkkinen, Pekka; Eskelinen, Antti; Mõkelõ, Keijo T
Background and purpose Previous population-based registry studies have shown that larger femoral head size is associated with reduced risk of revision for dislocation. However, the previous data have not included large numbers of hip resurfacing arthroplasties or large metal-on-metal (> 36-mm) femoral head arthroplasties. We evaluated the association between femoral component head size and the risk of revision for dislocation after THA by using Finnish Arthroplasty Register data. Patients and methods 42,379 patients who were operated during 1996¢2010 fulfilled our criteria. 18 different cup/stem combinations were included. The head-size groups studied (numbers of cases) were 28 mm (23,800), 32 mm (4,815), 36 mm (3,320), and > 36 mm (10,444). Other risk factors studied were sex, age group (18¢49 years, 50¢59 years, 60¢69 years, 70¢79 years, and > 80 years), and time period of operation (1996¢2000, 2001¢2005, 2006¢2010). Results The adjusted risk ratio in the Cox model for a revision operation due to dislocation was 0.40 (95% CI: 0.26¢0.62) for 32-mm head size, 0.41 (0.24¢0.70) for 36-mm head size, and 0.09 (0.05¢0.17) for > 36-mm head size compared to implants with a head size of 28 mm. Interpretation Larger femoral heads clearly reduce the risk of dislocation. The difference in using heads of > 36 mm as opposed to 28-mm heads for the overall revision rate at 10 years follow-up is about 2%. Thus, although attractive from a mechanical point of view, based on recent less favorable clinical outcome data on these large heads, consisting mainly of metal-on-metal prostheses, one should be cautious using these implants. PMID:23799348
A frictional study of total hip joint replacements.
Scholes, S C; Unsworth, A; Goldsmith, A A
Polymeric wear debris produced by articulation of the femoral head against the ultra-high-molecular-weight polyethylene socket of a total hip replacement has been implicated as the main cause of osteolysis and subsequent failure of these implants. Potential solutions to this problem are to employ hard bearing surface combinations such as metal-on-metal or ceramic-on-ceramic prostheses. The aim of this study was to investigate the difference in lubrication modes and friction of a range of material combinations using synthetic and biological fluids as the lubricants. The experimental results were compared with theoretical predictions of film thicknesses and lubrication modes. A strong correlation was observed between experiment and theory when employing carboxy methyl cellulose (CMC) fluids as the lubricant. Under these conditions the ceramic-on-ceramic joints showed full fluid film lubrication while the metal-on-metal, metal-on-plastic, diamond-like carbon-coated stainless steel (DLC)-on-plastic and ceramic-on-plastic prostheses operated under a mixed lubrication regime. With bovine serum as the lubricant in the all ceramic joints, however, the full fluid film lubrication was inhibited due to adsorbed proteins. In the metal-on-metal joints this adsorbed protein layer acted to reduce the friction while in the ceramic coupling the friction was increased. The use of bovine serum as the lubricant also significantly increased the friction in both the metal-on-plastic and ceramic-on-plastic joints. The friction produced by the DLC-on-plastic joints depended on the quality of the coating. Those joints with a less consistent coating and therefore a higher surface roughness gave significantly higher friction than the smoother, more consistently coated heads. PMID:11131195
Prediction of Impact Shock Vibrations at Tennis Player's Wrist Joint: Comparison between Conventional Weight Racket and Light Weight Racket with Super Large Head Size
NASA Astrophysics Data System (ADS)
Kawazoe, Yoshihiko; Takeda, Yukihiro; Nakagawa, Masamichi; Casolo, Federico; Tomosue, Ryoso; Yoshinari, Keiko
The lightweight racket with handle-light configuration and large head size is recent tendency of high-tech tennis rackets, increasing power or post-impact ball velocity with an increasing racket swing speed. This paper investigated the performance of lightweight tennis racket with super-large head size in terms of feel or comfort. It predicted the effect of the mass and mass distribution of super-large sized rackets on the impact shock vibrations of the racket handle and the player's wrist joint when a player hits a flat forehand drive. The prediction is based on the identification of the racket characteristics, the damping of the racket-arm system, equivalent mass of the player's arm system and the approximate nonlinear impact analysis in tennis. A super-light weight balanced racket (mass: 292 g, the center of gravity LG: 363 mm from the butt end) and a conventional weight and weight balanced racket (349 g, LG: 323 mm) are selected as representatives. They are the super-large sized rackets made of carbon graphite with a head size of 120 square inches and the same geometry. The result showed that the shock vibration of the super-light weight balanced racket with super-large sized head is much larger than that of the conventional weight balanced type racket. It also showed that the sweet area of the former in terms of the shock vibration shifts from the center to the topside on the racket face compared to the latter. This is because the location of the grip on the racket handle is further from the location of the node on the handle of the first mode of super-light racket than that of the conventional weight racket.
Metal ion levels in large-diameter total hip and resurfacing hip arthroplasty-Preliminary results of a prospective five year study after two years of follow-up
Background Metal-on-metal hip resurfacing is an alternative to metal-on-metal total hip arthroplasty, especially for young and physically active patients. However, wear which might be detected by increased serum ion levels is a matter of concern. Methods The aims of this preliminary study were to determine the raise of metal ion levels at 2-years follow-up in a prospective setting and to evaluate differences between patients with either resurfacing or total hip arthroplasty. Furthermore we investigated if the inclination of the acetabular component and the arc of cover would influence these findings. Therefore, 36 patients were followed prospectively. Results The results showed increments for Co and Cr in both implant groups. Patients treated with large-diameter total hip arthroplasty showed fourfold and threefold, respectively, higher levels for Co and Cr compared to the resurfacing group (Co: p?0,001 and Cr: p?=?0,005). Nevertheless, we observed no significant correlation between serum ion levels, inclination and arc of cover. Discussion In order to clarify the biologic effects of ion dissemination and to identify risks concerning long-term toxicity of metals, the exposure should be monitored carefully. Therefore, long-term studies have to be done to determine adverse effects of Co and Cr following metal-on-metal hip replacement. PMID:22494794
Early failures in total hip arthroplasty -- a changing paradigm.
Melvin, J Stuart; Karthikeyan, Tharun; Cope, Robert; Fehring, Thomas K
Between 2001 and 2011, 1168 revision hip arthroplasties were reviewed for "early" failures within 5 years of the primary total hip arthroplasty (THA). 24.1% underwent revision within 5 years of index THA. Aseptic loosening, infection, instability, metallosis, and fracture were common modes of failure. In our previous report from 1986 to 2000, 33% were "early" revisions, with instability and aseptic loosening accounting for over 70% of these early failures. While the proportion of "early" revisions decreased 9% from our previous report, this rate remains alarming. The emergence of metallosis and aseptic loosening of monoblock metal on metal shells as leading causes of early failures is concerning. This report suggests caution in the early adoption of new innovations before evidence based medicine is available to justify the risk of their use. PMID:24444568
A review of ceramic bearing materials in total joint arthroplasty.
Bal, B S; Garino, J; Ries, M; Rahaman, M N
Bearings made of ceramics have ultra-low wear properties that make them suitable for total hip arthroplasty (THA) and total knee arthroplasty (TKA). When compared to cobalt chrome (CoCr)-on-polyethylene (PE) articulations, ceramics offer drastic reductions in bearing wear rates. Lower wear rates result in fewer wear particles produced by the articulating surfaces. In theory, this should reduce the risk of periprosthetic osteolysis and premature implant loosening, thereby contributing to the longevity of total joints. In addition to ceramics, other alternative bearing couples, such as highly cross-linked PE (XLPE) and metal-on-metal also offer less wear than CoCr-on-PE articulations in total joint arthroplasty. Alumina and zirconia ceramics are familiar to orthopaedic surgeons since both materials have been used in total joints for several decades. While not new in Europe, alumina-on-alumina ceramic total hips have only recently become available for widespread use in the United States from various orthopaedic implant manufacturers. As the search for the ideal total joint bearing material continues, composite materials of existing ceramics, metal-on-ceramic articulations, and new ceramic technologies will offer more choices to the arthroplasty surgeon. The objective of this paper is to present an overview of material properties, clinical applications, evolution, and limitations of ceramic materials that are of interest to the arthroplasty surgeon. PMID:19197839
Metal-On-Metal Bonding and Rebonding Revisited
Bogicevic, A.
Density-functional calculations for a wide variety of metals show that, contrary to the rebonding view of adsorbate bonding, addimers do not have notably longer surface bonds than adatoms, do not reside farther above the surface, and do not meet the rebonding arguments for augmented mobility. Rebonding concepts are found to have some utility in explaining addimer stability.
Making A Noble-Metal-On-Metal-Oxide Catalyst
NASA Technical Reports Server (NTRS)
Miller, Irvin M.; Davis, Patricia P.; Upchurch, Billy T.
Catalyst exhibits superior performance in oxidation of CO in CO2 lasers. Two-step process developed for preparing platinum- or palladium-on-tin-oxide catalyst for recombination of CO and O2, decomposition products that occur in high-voltage discharge region of closed-cycle CO2 laser. Process also applicable to other noble-metal/metal-oxide combinations.
Implication of femoral stem on performance of articular surface replacement (ASR) XL total hip arthroplasty.
Cip, Johannes; von Strempel, Archibald; Bach, Christian; Luegmair, Matthias; Benesch, Thomas; Martin, Arno
Taper junctions of large diameter metal-on-metal femoral heads and femoral stems were described as metal ion generator due to accelerated wear and corrosion. However, literature about the Articular Surface Replacement (ASR) total hip arthroplasty (THA) invariably deals with stems manufactured by DePuy Orthopedics (Warsaw, IN, USA). Nothing is known whether different stems with common 12/14 mm tapers affect failure rate or ion release. 99 ASR THA (88 patients) implanted with CoxaFit or ARGE Geradschaft stems (K-Implant, Hannover, Germany) were retrospectively analyzed. After a mean follow-up of 3.5 years revision rate was 24.5%, mostly due to adverse reaction to metal debris (ARMD). CT scan revealed component loosening in 10.3% and pseudotumoral lesions in 12.6%. Elevated ion concentrations (>7 ?g/l) were found in 38.6%. PMID:25108735
Fracture of the modular femoral neck component in total hip arthroplasty.
Ellman, Michael B; Levine, Brett R
The use of modularity, specifically dual modular femoral stems, in total hip arthroplasty has increased in popularity over the past 2 decades. While offering several distinct advantages intraoperatively, the long-term success of adding a second modular junction has yet to be established. One potential complication of increasing modularity is component fracture. We present a case of modular femoral neck prosthesis fracture necessitating revision surgery to treat this complication. Careful preoperative planning during revision of these failures is essential to avoid morbidity and unnecessary subsequent revision surgeries, as demonstrated in this case. The combined effects of crevice and fretting corrosion, large-diameter femoral head, long modular neck, metal-on-metal articulation, patient size, and activity level may have all played integral roles in creating an environment susceptible to this classic pattern of fatigue fracture. PMID:21798696
Talbot Imlay
This article reviews the five volume series, published by Cambridge University Press, on the history of total war from the American Civil War and Wars of German Unification to World War II. The discussion focuses on two questions: how to define total war; and is total war a useful conceptual tool for understanding warfare during this period? Although the editors
Accelerating failure rate of the ASR total hip replacement.
Langton, D J; Jameson, S S; Joyce, T J; Gandhi, J N; Sidaginamale, R; Mereddy, P; Lord, J; Nargol, A V F
There is widespread concern regarding the incidence of adverse soft-tissue reactions after metal-on-metal (MoM) hip replacement. Recent National Joint Registry data have shown clear differences in the rates of failure of different designs of hip resurfacing. Our aim was to update the failure rates related to metal debris for the Articular Surface Replacement (ASR). A total of 505 of these were implanted. Kaplan-Meier analysis showed a failure rate of 25% at six years for the ASR resurfacing and of 48.8% for the ASR total hip replacement (THR). Of 257 patients with a minimum follow-up of two years, 67 (26.1%) had a serum cobalt concentration which was greater than 7 ?g/l. Co-ordinate measuring machine analysis of revised components showed that all patients suffering adverse tissue reactions in the resurfacing group had abnormal wear of the bearing surfaces. Six THR patients had relatively low rates of articular wear, but were found to have considerable damage at the trunion-taper interface. Our results suggest that wear at the modular junction is an important factor in the development of adverse tissue reactions after implantation of a large-diameter MoM THR. PMID:21768621
Hard-on-Hard Total Hip Impingement Causes Extreme Contact Stress Concentrations
Elkins, Jacob M.; OÆBrien, Megan K.; Stroud, Nicholas J.; Pedersen, Douglas R.; Callaghan, John J.
Background Impingement events, in addition to their role immediately proximate to frank dislocation, hold the potential to damage new-generation hard-on-hard bearings as a result of the relatively unforgiving nature of the materials and designs. Because of the higher stiffness and tighter design tolerances of metal-on-metal and ceramic implants, surgical positioning plausibly has become even more important. Questions/purposes We asked (1) whether, and under what cup orientation conditions, hard-on-hard impingements might challenge implant material failure strength; and (2) whether particle generation propensity at impingement and egress sites would show similar dependence on cup orientation. Methods Realistic computational simulations were enabled by multistage finite element analyses, addressing both global construct motion and loading, and focal stress concentrations at neck impingement and rim egress sites. The global model, validated by a cadaveric simulation in a servohydraulic hip simulator, included both hardware components and advanced anisotropic capsule characterization. Parametric computational runs explored the effect of cup orientation for both ceramic-on-ceramic and metal-on-metal bearing couples for two distinct motion sequences associated with dislocation. Results Stress concentrations from impingement increased nearly linearly with increased cup tilt and with cup anteversion. In some situations, peak values of stress approached or exceeded 1 GPa, levels challenging the yield strength of cobalt-chromium implants, and potentially the fracture strength of ceramics. The tendency for impingement events to generate debris, indexed in terms of a new scraping severity metric, showed orientation dependences similar to that for bulk material failure. Conclusions Damage propensity arising from impingement events in hard total hip bearings is highly orientation-dependent. PMID:20953853
Changes in bone mineral density of the acetabulum and proximal femur after total hip resurfacing arthroplasty.
Huang, Qiang; Shen, Bin; Yang, Jing; Zhou, Zong-ke; Kang, Peng-de; Pei, Fu-xing
Our aim was to investigate the changes in bone mineral density (BMD) of acetabulum and proximal femur after total hip resurfacing arthroplasty. A comparative study was carried out on 51 hips in 48 patients. Group A consisted of 25 patients (26 hips) who had undergone total hip resurfacing and group B consisted of 23 patients (25 hips) who had had large-diameter metal-on-metal total hip arthroplasty (THA). BMDs around the acetabulum and proximal femur were measured using dual-energy x-ray absorptiometry (DEXA) at 2 weeks, 6 months, 1 year and annually thereafter during the 3 years after surgery. At final follow-up, the acetabular net mean BMD decreased by 11% in group A and 10% in group B with no differences between two groups (P = .35). For the femoral side, in Gruen zone 1, the mean BMD increased by 4% in group A, whereas it decreased by 11% in group B (P = .029). In Gruen zone 7, the mean BMD increased by 8% at the final follow-up in group A, whereas it decreased by 13% in group B (P = .02). In both groups the mean BMD increased by 3% in Gruen zones 3, 4, 5, and 6. Stress-related bone loss of the acetabulum was comparable for MOM THA and resurfacing devices, but proximal femoral bone density increased in the resurfacing group and decreased in the THA group. PMID:23618750
Alumina-on-alumina total hip replacement for femoral neck fracture in healthy patients
Background Total hip replacement is considered the best option for treatment of displaced intracapsular fractures of the femoral neck (FFN). The size of the femoral head is an important factor that influences the outcome of a total hip arthroplasty (THA): implants with a 28 mm femoral head are more prone to dislocate than implants with a 32 mm head. Obviously, a large head coupled to a polyethylene inlay can lead to more wear, osteolysis and failure of the implant. Ceramic induces less friction and minimal wear even with larger heads. Methods A total of 35 THAs were performed for displaced intracapsular FFN, using a 32 mm alumina-alumina coupling. Results At a mean follow-up of 80 months, 33 have been clinically and radiologically reviewed. None of the implants needed revision for any reason, none of the cups were considered to have failed, no dislocations nor breakage of the ceramic components were recorded. One anatomic cementless stem was radiologically loose. Conclusions On the basis of our experience, we suggest that ceramic-on-ceramic coupling offers minimal friction and wear even with large heads. PMID:21284879
Late Nontraumatic Dissociation of the Femoral Head and Trunnion in a Total Hip Arthroplasty
Parker, Simon J. M.; Khan, Wasim; Mellor, Simon
Background. Modular total hip arthroplasties are increasingly popular because customisation allows optimal restoration of patient biomechanics. However, the introduction of component interfaces provides greater opportunities for failure. We present a case of late nontraumatic dissociation of the head-neck interface, more than 10 years after insertion. Case Description. A 58-year-old woman had a left metal-on-metal total hip arthroplasty in 2002 for hip dysplasia. Following an uneventful 10-year period, she presented to hospital in severe pain after standing from a seated position, and radiographs demonstrated complete dissociation of the modular femoral head from the stem, with the femoral head remaining in its cup. There was no prior trauma or infection. Mild wear and metallosis were present on the articulating surface between the femoral head and trunnion. Soft tissues were unaffected. Discussion and Conclusions. This is the latest occurrence reported to date for nontraumatic component failure in such an implant by more than 7 years. The majority of cases occur in the context of dislocation and attempted closed reduction. We analyse and discuss possible mechanisms for failure, aiming to raise awareness of this potential complication and encouraging utmost care in component handling and insertion, as well as the long term follow-up of such patients.
Johnson Jr.,, Ray
NYPD *Non DPS Section TOTAL Murder/Non-Negligent Manslaughter 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 TOTAL DPS NYPD *Non DPS TOTAL Murder/Non-Negligent Manslaughter 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 *Non DPS TOTAL TOTAL DPS NYPD *Non DPS TOTAL Murder/Non-Negligent Manslaughter 0 0 0 0 0 0 0 0 0 0 0 0
Early Failure of Articular Surface Replacement XL Total Hip Arthroplasty
Garen D. Steele; Thomas K. Fehring; Susan M. Odum; Anne C. Dennos; Matthew C. Nadaud
The ASR (articular surface replacement) XL (DePuy, Warsaw, Ind) metal-on-metal hip arthroplasty offers the advantage of stability and increased motion. However, an alarming number of early failures prompted the evaluation of patients treated with this system. A prospective study of patients who underwent arthroplasty with the ASR XL system was performed. Patients with 2-year follow-up or any revision were included.
... NHLBI on Twitter. What Is a Total Artificial Heart? A total artificial heart (TAH) is a device ... the chest to an outside power source. Normal Heart and CardioWest Total Artificial Heart Figure A shows ...
State University Total Federal
Fernandez, Eduardo
) Total Enrollment Fall 2012* Graduate Enrollment % Graduate of Total Enrollment Median SAT Pell Grant reporting date of October 15, 2012. ** Under-represented minorities include: Black, Hispanic, Native
Metal release and metal allergy after total hip replacement with resurfacing versus conventional hybrid prosthesis
Gustafson, Klas; Jakobsen, Stig S; Lorenzen, Nina D; Thyssen, Jacob P; Johansen, Jeanne D; Bonefeld, Charlotte M; Stilling, Maiken; Baad-Hansen, Thomas; S°balle, Kjeld
Background Metal-on-metal (MOM) total hip arthroplasties were reintroduced because of the problems with osteolysis and aseptic loosening related to polyethylene wear of early metal-on-polyethylene (MOP) arthroplasties. The volumetric wear rate has been greatly reduced with MOM arthroplasties; however, because of nano-size wear particles, the absolute number has been greatly increased. Thus, a source of metal ion exposure with the potential to sensitize patients is present. We hypothesized that higher amounts of wear particles result in increased release of metal ions and ultimately lead to an increased incidence of metal allergy. Methods 52 hips in 52 patients (median age 60 (51¢64) years, 30 women) were randomized to either a MOM hip resurfacing system (ReCap) or a standard MOP total hip arthoplasty (Mallory Head/Exeter). Spot urine samples were collected preoperatively, postoperatively, after 3 months, and after 1, 2, and 5 years and tested with inductively coupled plasma-sector field mass spectrometry. After 5 years, hypersensitivity to metals was evaluated by patch testing and lymphocyte transformation assay. In addition, the patients answered a questionnaire about hypersensitivity. Results A statistically significant 10- to 20-fold increase in urinary levels of cobalt and chromium was observed throughout the entire follow-up in the MOM group. The prevalence of metal allergy was similar between groups. Interpretation While we observed significantly increased levels of metal ions in the urine during the entire follow-up period, no difference in prevalence of metal allergy was observed in the MOM group. However, the effect of long-term metal exposure remains uncertain. PMID:24930546
Enhanced wear and corrosion in modular tapers in total hip replacement is associated with the contact area and surface topography.
Panagiotidou, Anna; Meswania, Jay; Hua, Jia; Muirhead-Allwood, Sarah; Hart, Alister; Blunn, Gordon
Widespread concern exists about adverse tissue reactions after metal-on-metal (MoM) total hip replacement (THR). Concerns have also been expressed with wear and corrosion of taper junctions in THR. We report the effect of surface finish and contact area associated with a single combination of materials of modular tapers. In an in vitro test, we investigated the head/neck (CoCrMo/Ti) interface of modular THRs using commercially available heads. Wear and corrosion of taper surfaces was compared following a 10 million loading cycle. Surface parameters and profiles were measured before and after testing. Electrochemical static and dynamic corrosion tests were performed under loaded and non-loaded conditions. After the load test, the surface roughness parameters on the head taper were significantly increased where the head/neck contact area was reduced. Similarly, the surface roughness parameters on the head taper were significantly increased where rough neck tapers were used. Corrosion testing showed breaching of the passive film on the rough but not the smooth neck tapers. Thus, surface area and surface finish are important factors in wear and corrosion at modular interfaces. PMID:23966288
Metal on metal oxide nanowire Co-catalyzed Si photocathode for solar water splitting
NASA Astrophysics Data System (ADS)
Sun, Ke; Madsen, Kristian; Andersen, PÕl; Bao, Weining; Sun, Zhelin; Wang, Deli
We report a systematic study of Si|ZnO and Si|ZnO| metal photocathodes for effective photoelectrochemical cells and hydrogen generation. Both ZnO nanocrystalline thin films and vertical nanowire arrays were studied. Si|ZnO electrodes showed increased cathodic photocurrents due to improved charge separation by the formation of a p/n junction, and Si|ZnO:Al (n+-ZnO) and Si|ZnO(N2) (thin films prepared in N2/Ar gas) lead to a further increase in cathodic photocurrents. Si|ZnONW (nanowire array) photocathodes dramatically increased the photocurrents and thus photoelectrochemical conversion efficiency due to the enhanced light absorption and enlarged surface area. The ZnO film thickness and ZnO nanowire length were important to the enhancements. A thin metal coating on ZnO showed increased photocurrent due to a catalyzed hydrogen evolution reaction and Ni metal showed comparable catalytic activities to those of Pt and Pd. Moreover, photoelectrochemical instability of Si|ZnO electrodes was minimized by metal co-catalysts. Our results indicate that the metal and ZnO on p-type Si serve as co-catalysts for photoelectrochemical water splitting, which can provide a possible low-cost and scalable method to fabricate high efficiency photocathodes for practical applications in clean solar energy harvesting.
Ref. p. 251] 3.3.1 Metals on metals Landolt-Brnstein
Brune, Harald
are condensed on the surface from the vapor phase in an ultra-high vacuum (UHV) chamber. As adsorbate materials of the substrate lattice, or whether the adsorbate performs transient, non-thermal, motion over a few lattice sites until its adsorption energy is dissipated. Sect. 3 is devoted to this so-called transient (non-thermal
Information for Patients Who Have Metal-on-Metal Hip Implants
... when revision surgery is advisable. What are the risks of revision surgery? Any surgical procedure, including revision surgery, has risks associated with it, including reaction to the anesthesia, ...
New insights into hard phases of CoCrMo metal-on-metal hip replacements.
Liao, Y; Pourzal, R; Stemmer, P; Wimmer, M A; Jacobs, J J; Fischer, A; Marks, L D
The microstructural and mechanical properties of the hard phases in CoCrMo prosthetic alloys in both cast and wrought conditions were examined using transmission electron microscopy and nanoindentation. Besides the known carbides of M(23)C(6)-type (M=Cr, Mo, Co) and M(6)C-type which are formed by either eutectic solidification or precipitation, a new mixed-phase hard constituent has been found in the cast alloys, which is composed of ?100 nm fine grains. The nanosized grains were identified to be mostly of M(23)C(6) type using nano-beam precession electron diffraction, and the chemical composition varied from grain to grain being either Cr- or Co-rich. In contrast, the carbides within the wrought alloy having the same M(23)C(6) structure were homogeneous, which can be attributed to the repeated heating and deformation steps. Nanoindentation measurements showed that the hardness of the hard phase mixture in the cast specimen was ?15.7 GPa, while the M(23)C(6) carbides in the wrought alloy were twice as hard (?30.7 GPa). The origin of the nanostructured hard phase mixture was found to be related to slow cooling during casting. Mixed hard phases were produced at a cooling rate of 0.2 ░C/s, whereas single phase carbides were formed at a cooling rate of 50 ░C/s. This is consistent with sluggish kinetics and rationalizes different and partly conflicting microstructural results in the literature, and could be a source of variations in the performance of prosthetic devices in-vivo. PMID:22659365
Origin of Compact Triangular Islands in Metal-on-Metal Growth
Ovesson, S.; Lundqvist, B.I. [Department of Applied Physics, Chalmers University of Technology and Goeteborg University, S-412 96 Goeteborg (Sweden)] [Department of Applied Physics, Chalmers University of Technology and Goeteborg University, S-412 96 Goeteborg (Sweden); Bogicevic, A. [Department of Surface and Interface Sciences, Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States)] [Department of Surface and Interface Sciences, Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States)
The microscopic origin of compact triangular islands on close-packed surfaces is identified using kinetic Monte Carlo simulations with energy barriers obtained from density-functional calculations. In contrast to earlier accounts, corner diffusion anisotropy is found to control the shape of compact islands at intermediate temperatures. We rationalize the correlation between the orientation of dendrites grown at low temperatures and triangular islands grown at higher temperatures, and explain why in some systems dendrites grow fat before turning compact. {copyright} {ital 1999} {ital The American Physical Society}
State University Total Federal
Fernandez, Eduardo
) Total Enrollment Fall 2011 Graduate Enrollment % Graduate of Total Enrollment Median SAT % Pell Grant,899 8,145 26% 1080 21% 30% 16% n/a 50.7% 86.0% * Under-represented minorities include: Black, Hispanic
Currently, the most popular method of analyzing total dissolved halide in water involves carbon adsorption, oxidative combustion, and measurement of the hydrogen halide by microcoulometry. Total dissolved organic halide can be used as an indicator of water quality, providing a di...
Siopack, J S; Jergesen, H E
Total hip arthroplasty, or surgical replacement of the hip joint with an artificial prosthesis, is a reconstructive procedure that has improved the management of those diseases of the hip joint that have responded poorly to conventional medical therapy. In this review we briefly summarize the evolution of total hip arthroplasty, the design and development of prosthetic hip components, and the current clinical indications for this procedure. The possible complications of total hip arthroplasty, its clinical performance over time, and future directions in hip replacement surgery are also discussed. Images PMID:7725707
Total Synthesis of (?)-Himandrine
Movassaghi, Mohammad
We describe the first total synthesis of (?)-himandrine, a member of the class II galbulimima alkaloids. Noteworthy features of this chemistry include a diastereoselective Diels?Alder reaction in the rapid synthesis of the ...
... ankle pump exercises, and early mobilization. Leg-length Inequality Sometimes a er a hip replacement, one leg ... Surgeons (AAOS). To learn more about your orthopaedic health, please visit orthoinfo.org. Total Hip Replacement cont.
NSDL National Science Digital Library
Optical Society of America
In this activity, learners use a laser pointer, empty soda bottle, rubber plug and water to demonstrate total internal reflection. Use this simple activity as a demonstration or group activity to explore reflection, refraction, fiber optics, and Snell's Law. This resource contains background information about total internal reflection, the equation for Snell's Law, and refractive indexes as well as links to articles about reflection and refraction of light.
NSDL National Science Digital Library
Solar eclipses result from the alignment of the Sun, Moon, and Earth. Total solar eclipses, in which the Sun is completely blocked by the Moon, are a spectacular and rare sight to witness. This animation, adapted from a NOVA television broadcast, shows a simulated total eclipse and explains some of the features that can be seen. The clip is one minute thirteen seconds in length.
Friedrich, S
The total energy monitor (TE) is a thermal sensor that determines the total energy of each FEL pulse based on the temperature rise induced in a silicon wafer upon absorption of the FEL. The TE provides a destructive measurement of the FEL pulse energy in real-time on a pulse-by-pulse basis. As a thermal detector, the TE is expected to suffer least from ultra-fast non-linear effects and to be easy to calibrate. It will therefore primarily be used to cross-calibrate other detectors such as the Gas Detector or the Direct Imager during LCLS commissioning. This document describes the design of the TE and summarizes the considerations and calculations that have led to it. This document summarizes the physics behind the operation of the Total Energy Monitor at LCLS and derives associated engineering specifications.
Fuwa, Haruhiko; Sasaki, Makoto; Satake, Masayuki; Tachibana, Kazuo
[structure: see text] The first total synthesis of gambierol, a marine polycyclic ether toxin, has been achieved. The synthesis features the Pd(PPh3)4/CuCl/LiCl-promoted Stille coupling for the stereoselective construction of the sensitive triene side chain that includes a conjugated (Z,Z)-diene moiety. PMID:12182604
Totally frictionless magnetic bearing
Wayne Dodakian; John Bulman
A totally frictionless magnetic bearing has been developed which supports a rotor in a contactless manner. The rotor is held in a magnetic potential well via repulsive forces only. Vertical and lateral restoring forces are provided to the rotor passively via permanent magnets in such an arrangement so as to support the weight of the rotor and provide it with
A Minneapolis company, Total Tree Chips, Inc., originally formed to chip city trees killed by Dutch elm disease, has expanded to include operations such as clearing land for parks and shopping centers and selling some of the chipped material back to the owners for trails and landscaping. Excess chips are sold to civic and commercial developments for landscaping, to a
Exposures Information Totals Calls
Oliver, Douglas L.
Information Call Type Totals Calls 2010: 30,979 2011: 29,916 #12;0 500 1000 1500 2000 2500 3000 3500 1 2 3 4 5 Fatalities 17.5 #12;CT Health Care Facility Initiated Calls 2011 2010 Bridgeport Hospital 181 152 St. Vincent's Hospital 215 189 Bristol Hospital 192 168 Danbury Hospital 211 172 Griffin Hospital 96 103 John Dempsey
Total synthesis of (-)-goniotrionin.
Dias, Luiz C; Ferreira, Marco A B
A stereoselective total synthesis of the reported structure of goniotrionin (4) has been accomplished. The key steps involved the opening of a chiral epoxide, a highly diastereoselective Mukaiyama aerobic oxidative cyclization, a selective 1,2-syn Mukaiyama aldol reaction, and a Noyori reduction. PMID:22443275
NSDL National Science Digital Library
Imre, John
Total Quality Management is a lesson plan which provides students with a broad introduction to the quality approaches used in manufacturing. After completing this module, students should be able to apply various quality improvement techniques during a simulated manufacturing process. Note: This module is part of a modularized manufacturing technology curriculum created by the PSCME, found at www.pscme.org/educators.html.
Total Quality Management Seminar.
ERIC Educational Resources Information Center
Massachusetts Career Development Inst., Springfield.
This booklet is one of six texts from a workplace literacy curriculum designed to assist learners in facing the increased demands of the workplace. The booklet contains seven sections that cover the following topics: (1) meaning of total quality management (TQM); (2) the customer; (3) the organization's culture; (4) comparison of managementģ
Total Quality Management Simplified.
ERIC Educational Resources Information Center
Arias, Pam
Maintains that Total Quality Management (TQM) is one method that helps to monitor and improve the quality of child care. Lists four steps for a child-care center to design and implement its own TQM program. Suggests that quality assurance in child-care settings is an ongoing process, and that TQM programs help in providing consistent, high-qualityģ
J. Field; T. J. Herbert; R. Prosser
Twenty cases of total wrist fusion, performed for post-traumatic conditions, were reviewed objectively, subjectively and radiologically. All patients were satisfied with the position of the fused wrist and had good pain relief. All patients would have had the procedure sooner, having had an average of three operations on the wrist before the fusion. There was a high complication rate (45%),
Total synthesis of (+)-cyperolone.
Klahn, Philipp; Duschek, Alexander; Liķbert, Clķmence; Kirsch, Stefan F
The total synthesis of (+)-cyperolone, an eudesmane-derived sesquiterpenoid from Cyperus rotundus, is described. The de novo synthesis was accomplished via a 15 step sequence starting from (R)-(-)-carvone. The synthetic route features a platinum-catalyzed cycloisomerization to rapidly construct the bicyclic core from a 3-silyloxy-1,5-enyne intermediate. PMID:22324453
The simulation was performed on 64K cores of Intrepid, running at 0.25 simulated-years-per-day and taking 25 million core-hours. This is the first simulation using both the CAM5 physics and the highly scalable spectral element dynamical core. The animation of Total Precipitable Water clearly shows hurricanes developing in the Atlantic and Pacific.
Early failure of articular surface replacement XL total hip arthroplasty.
Steele, Garen D; Fehring, Thomas K; Odum, Susan M; Dennos, Anne C; Nadaud, Matthew C
The ASR (articular surface replacement) XL (DePuy, Warsaw, Ind) metal-on-metal hip arthroplasty offers the advantage of stability and increased motion. However, an alarming number of early failures prompted the evaluation of patients treated with this system. A prospective study of patients who underwent arthroplasty with the ASR XL system was performed. Patients with 2-year follow-up or any revision were included. Failure rates, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and radiographs were evaluated. Ninety-five patients (105 hips) were included. There were 16 revisions. Thirteen (12%) were aseptic acetabular failures. Eight were revised for aseptic loosening; 4, for metallosis; 1, for malposition; 2, for infection; and 1, for periprosthetic fracture. Mean time to revision was 1.6 years (0.18-3.4 years). The ASR XL with a revision rate of 12% is the second reported 1 piece metal-on-metal system with a significant failure rate at early follow-up. This particular class of implants has inherent design flaws that lead to early failure. PMID:21550764
Yang, Ming; Li, Jian; Li, Ang
Clostrubin is a potent antibiotic against methicillin- and vancomycin-resistant bacteria that was isolated from a strictly anaerobic bacterium Clostridium beijerinckii in 2014. This polyphenol possesses a fully substituted arene moiety on its pentacyclic scaffold, which poses a considerable challenge for chemical synthesis. Here we report the first total synthesis of clostrubin in nine steps (the longest linear sequence). A desymmetrization strategy is exploited based on the inherent structural feature of the natural product. Barton¢Kellogg olefination forges the two segments together to form a tetrasubstituted alkene. A photo-induced 6? electrocyclization followed by spontaneous aromatization constructs the hexasubstituted B ring at a late stage. In total, 200?mg of clostrubin are delivered through this approach. PMID:25759087
Richard G. Godec; Paul P. Kosenka; Brian D. Smith; Richard S. Hutte; Johanna V. Webb; Richard L. Sauer
The development and testing of a breadboard version of a highly sensitive total-organic-carbon (TOC) analyzer are reported. Attention is given to the system components including the CO2 sensor, oxidation reactor, acidification module, and the sample-inlet system. Research is reported for an experimental reagentless oxidation reactor, and good results are reported for linearity, sensitivity, and selectivity in the CO2 sensor. The
Yamashita, Shuji; Naruko, Akito; Nakazawa, Yuki; Zhao, Le; Hayashi, Yujiro; Hirama, Masahiro
Limonoids are highly oxygenated C13?-triterpenes and common secondary metabolites. Several hundred congeners have been isolated to date. The first total synthesis of (▒)-limonin, the flagship congener of the limonoids, is now reported and features 1)?a tandem radical cyclization generating the BCD ring system with the C13? configuration that is essential to the limonoids and a Robinson annulation to construct the limonoid androstane framework, 2)?a singlet-oxygen cycloaddition and a Baeyer-Villiger oxidation to synthesize the highly oxidized D?ring, and 3)?a Sußrez reaction to construct the unique AA' ring system. PMID:26036432
Totally frictionless magnetic bearing
NASA Astrophysics Data System (ADS)
Dodakian, Wayne; Bulman, John
A totally frictionless magnetic bearing has been developed which supports a rotor in a contactless manner. The rotor is held in a magnetic potential well via repulsive forces only. Vertical and lateral restoring forces are provided to the rotor passively via permanent magnets in such an arrangement so as to support the weight of the rotor and provide it with a high degree of lateral stability. Axial stability of the rotor is provided by the use of an electromagnet which is controlled by a PID control loop. Information on the axial position of the rotor is provided to the circuit by use of an infrared LED and IR phototransistor. To prevent unwanted oscillations of the rotorÆs axial position from occurring, an oscillation sensor in the form of an inductive pick-up coil of high impedance provides signals to the oscillation sensing portion of the circuit, which in turn feeds the oscillation dampening circuit. The use of only repulsive forces in stabilizing the rotor means that there will be no eddy current losses or hysterisis losses. Such a frictionless magnetic bearing can, for example be used in rotational oscillation experiments and ultra low loss watt-hour meters, which are of great importance to utility companies. When properly tuned, the total power requirements of the circuit is a mere 40mW, which is less than the 80 mW used by present day watt-hour meters.
Cervical Total Disc Arthroplasty
Basho, Rahul; Hood, Kenneth A.
Symptomatic adjacent segment degeneration of the cervical spine remains problematic for patients and surgeons alike. Despite advances in surgical techniques and instrumentation, the solution remains elusive. Spurred by the success of total joint arthroplasty in hips and knees, surgeons and industry have turned to motion preservation devices in the cervical spine. By preserving motion at the diseased level, the hope is that adjacent segment degeneration can be prevented. Multiple cervical disc arthroplasty devices have come onto the market and completed Food and Drug Administration Investigational Device Exemption trials. Though some of the early results demonstrate equivalency of arthroplasty to fusion, compelling evidence of benefits in terms of symptomatic adjacent segment degeneration are lacking. In addition, non-industry-sponsored studies indicate that these devices are equivalent to fusion in terms of adjacent segment degeneration. Longer-term studies will eventually provide the definitive answer. PMID:24353955
NASA Technical Reports Server (NTRS)
Godec, Richard G.; Kosenka, Paul P.; Smith, Brian D.; Hutte, Richard S.; Webb, Johanna V.; Sauer, Richard L.
The development and testing of a breadboard version of a highly sensitive total-organic-carbon (TOC) analyzer are reported. Attention is given to the system components including the CO2 sensor, oxidation reactor, acidification module, and the sample-inlet system. Research is reported for an experimental reagentless oxidation reactor, and good results are reported for linearity, sensitivity, and selectivity in the CO2 sensor. The TOC analyzer is developed with gravity-independent components and is designed for minimal additions of chemical reagents. The reagentless oxidation reactor is based on electrolysis and UV photolysis and is shown to be potentially useful. The stability of the breadboard instrument is shown to be good on a day-to-day basis, and the analyzer is capable of 5 sample analyses per day for a period of about 80 days. The instrument can provide accurate TOC and TIC measurements over a concentration range of 20 ppb to 50 ppm C.
Friedrich, S; Kolagani, R M
The following outlines the optimized pulsed laser deposition (PLD) procedure used to prepare Nd{sub 0.67}Sr{sub 0.33}MnO{sub 3} (NSMO) temperature sensors at Towson University (Prof. Rajeswari Kolagani) for the LCLS XTOD Total Energy Monitor. The samples have a sharp metal/insulator transition at T {approx} 200 K and are optimized for operation at T {approx} 180 K, where their sensitivity is the highest. These samples are epitaxial multilayer structures of Si/YSZ/CeO/NSMO, where these abbreviations are defined in table 1. In this heterostructure, YSZ serves as a buffer layer to prevent deleterious chemical reactions, and also serves to de-oxygenate the amorphous SiO{sub 2} surface layer to generate a crystalline template for epitaxy. CeO and BTO serve as template layers to minimize the effects of thermal and lattice mismatch strains, respectively. More details on the buffer and template layer scheme are included in the attached manuscript accepted for publication in Sensor Letters (G. Yong et al., 2008).
Galassi, Alfredo R; Tomasello, Salvatore D; Costanzo, Luca; Tamburino, Corrado
Many studies showed that successful recanalization of chronic total occlusion (CTO) provides an improvement of long-term outcome and left ventricular ejection fraction, electrical stability of the myocardium, increased tolerance to future coronary events, and last but not least an improvement in quality of life. Because of the perceived procedural complexity of percutaneous coronary interventions (PCI), patients with CTO are usually referred to coronary artery bypass surgery or medical therapy. Recent advances in PCI materials, devices, approaches, and techniques have allowed expert operators to tackle successfully with complex cases of CTO that many years ago would have sent patients to surgery. This has also been motivated by the long-term patency and freedom from restenosis obtained by drug-eluting stent implantation. Each strategy and device has advantages and disadvantages, even though percutaneous treatment of CTO needs a higher operator's skill with respect to other non-occlusive lesions as well as an appropriate training period. In order to avoid complications and to achieve CTO recanalization in more than 70% of cases, it is advisable to understand the principles of each strategy, to plan the proper strategy and choose the appropriate materials, to take time, to be zen and aware when to stop. PMID:18942554
Determination of Total Petroleum Hydrocarbons (TPH) Using Total Carbon Analysis
Ekechukwu, A.A.
Several methods have been proposed to replace the Freon(TM)-extraction method to determine total petroleum hydrocarbon (TPH) content. For reasons of cost, sensitivity, precision, or simplicity, none of the replacement methods are feasible for analysis of radioactive samples at our facility. We have developed a method to measure total petroleum hydrocarbon content in aqueous sample matrixes using total organic carbon (total carbon) determination. The total carbon content (TC1) of the sample is measured using a total organic carbon analyzer. The sample is then contacted with a small volume of non-pokar solvent to extract the total petroleum hydrocarbons. The total carbon content of the resultant aqueous phase of the extracted sample (TC2) is measured. Total petroleum hydrocarbon content is calculated (TPH = TC1-TC2). The resultant data are consistent with results obtained using Freon(TM) extraction followed by infrared absorbance.
Total Laparoscopic Pancreaticoduodenectomy
Kamyab, Armin
Introduction: Total laparoscopic pancreaticoduodenectomy (TLPD) remains one of the most advanced laparoscopic procedures. Owing to the evolution in laparoscopic technology and instrumentation within the past decade, laparoscopic pancreaticoduodenectomy is beginning to gain wider acceptance. Methods: Data were collected for all patients who underwent a TLPD at our institution. Preoperative evaluation consisted of computed tomography scan with pancreatic protocol and selective use of magnetic resonance imaging and/or endoscopic ultrasonography. The TLPD was done with 6 ports on 3 patients and 5 ports in 2 patients and included a celiac, periportal, peripancreatic, and periduodenal lymphadenectomy. Pancreatic stents were used in all 5 cases, and intestinal continuity was re-established by intracorporeal anastomoses. Results: Five patients underwent a TLPD for suspicion of a periampullary tumor. There were 3 women and 2 men with a mean age of 60 years and a mean body mass index of 32.8. Intraoperatively, the mean operative time was 9 hours 48 minutes, with a mean blood loss of 136 mL. Postoperatively, there were no complications and a mean length of stay of 6.6 days. There was no lymph node involvement in 4 out of 5 specimens. The pathological results included intraductal papillary mucinous neoplasm in 2 patients, pancreatic adenocarcinoma in 1 patient (R0 resection), benign 4-cm periampullary adenoma in 1 patient, and a somatostatin neuroendocrine carcinoma in 1 patient (R0, N1). Conclusion: TLPD is a viable alternative to the standard Whipple procedure. Our early experience suggests decreased length of stay, quicker recovery, and improved quality of life. Complication rates appear to be improved or equivalent. PMID:23925010
Recommended Amounts of Total dairy
Recommended Amounts of Total dairy Table B15. Total dairy: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting recommendation (SE) % with intake above
Recommended Amounts of Total seafood
Recommended Amounts of Total seafood Table B12. Total seafood: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting recommendation (SE) % with intake
Recommended Amounts of Total grains
Recommended Amounts of Total grains Table B8. Total grains: Estimated percentage of persons below, at, or above recommendation1 Age (years) N Mean (SE) % with intake below recommendation (SE) % with intake meeting recommendation (SE) % with intake above
7, 1782517871, 2007 Total Observed
Paris-Sud XI, Universitķ de
ACPD 7, 17825Ł17871, 2007 Total Observed Organic Carbon (TOOC) C. L. Heald et al. Title Page Chemistry and Physics Discussions Total Observed Organic Carbon (TOOC): A synthesis of North American, USA 17825 #12;ACPD 7, 17825Ł17871, 2007 Total Observed Organic Carbon (TOOC) C. L. Heald et al. Title
Monitoring the introduction and performance of a joint replacement: the United Kingdom metal-on-metal alert.
Tucker, Keith; Gregg, Paul; Kay, Peter; Porter, Martyn; Howard, Peter; Pickford, Martin; Cacou, Crina
Recent events have made us question our ability to monitor the introduction and performance of a new prosthetic joint replacement. These concerns are mirrored in many other countries, even those with joint registries and other systems for detecting poorly performing implants. In the United Kingdom, as is the case in most European Union countries, we have assessment processes in place, particularly the CE (Conformitķ Europķenne) mark, the National Joint Registry, and the Orthopaedic Data Evaluation Panel. It is important to realize that these organizations can only react to poor performance; it is not within their power as monitoring agencies to prevent a poor implant from entering the market. When an implant has been shown to perform badly, it is referred to the Medicines and Healthcare products Regulatory Agency (MHRA), which then discusses the report with the manufacturer. When it is deemed that there is unequivocal evidence of a serious problem with the implant, the MHRA issues alerts to all hospitals and practitioners. We have continuing concerns about how to assess and monitor modifications to already existing devices. Suggestions are made for improvements to this system, and the authors will welcome feedback. PMID:22262421
Tribology of high-speed metal-on-metal sliding at near-melt and fully-melt interfacial temperatures
Makoto Okada; Nai-Shang Liou; Vikas Prakash; Kazuhisa Miyoshi
The present paper describes results of plate-impact friction experiments conducted to study time-resolved frictional characteristics of sliding interfaces under extreme conditions. By employing pressure¢shear impact of tribo¢pair materials comprising hard tool-steels against low melt-point metals such as 7075-T6 Al alloys, interfacial normal pressures ranging from 1 to 2GPa and slip-speeds of approximately 100m\\/s have been obtained. The resulting relatively large
Corrosion at the Head-Neck Taper as a Cause for Adverse Local Tissue Reactions After Total Hip Arthroplasty
John Cooper, H.; Della Valle, Craig J.; Berger, Richard A.; Tetreault, Matthew; Paprosky, Wayne G.; Sporer, Scott M.; Jacobs, Joshua J.
Background: Corrosion at the modular head-neck junction of the femoral component in total hip arthroplasty has been identified as a potential concern, although symptomatic adverse local tissue reactions secondary to corrosion have rarely been described. Methods: We retrospectively reviewed the records of ten patients with a metal-on-polyethylene total hip prosthesis, from three different manufacturers, who underwent revision surgery for corrosion at the modular head-neck junction. Results: All patients presented with pain or swelling around the hip, and two patients presented with recurrent instability. Serum cobalt levels were elevated prior to the revision arthroplasty and were typically more elevated than were serum chromium levels. Surgical findings included large soft-tissue masses and surrounding tissue damage with visible corrosion at the femoral head-neck junction; the two patients who presented with instability had severe damage to the hip abductor musculature. Pathology specimens consistently demonstrated areas of tissue necrosis. The patients were treated with debridement and a femoral head and liner exchange, with use of a ceramic femoral head with a titanium sleeve in eight cases. The mean Harris hip score improved from 58.1 points preoperatively to 89.7 points at a mean of 13.0 months after the revision surgery (p = 0.01). Repeat serum cobalt levels, measured in six patients at a mean of 8.0 months following revision, decreased to a mean of 1.61 ng/mL, and chromium levels were similar to prerevision levels. One patient with moderate hip abductor muscle necrosis developed recurrent instability after revision and required a second revision arthroplasty. Conclusions: Adverse local tissue reactions can occur in patients with a metal-on-polyethylene bearing secondary to corrosion at the modular femoral head-neck taper, and their presentation is similar to the adverse local tissue reactions seen in patients with a metal-on-metal bearing. Elevated serum metal levels, particularly a differential elevation of serum cobalt levels with respect to chromium levels, can be helpful in establishing this diagnosis. Level of Evidence: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence. PMID:23289127
Total Productive Maintenance and Its Link to Total Quality Management
Robert S. Jostes; Marilyn M. Helms
This article addresses the question of why total quality management (TQM) and total productive maintenance (TPM) are valuable strategies for American businesses today. While each process is beneficial on its own, the synergy created by simultaneously doing both is incredibly powerful.
Total quality index: a benchmarking tool for total quality management
Madjid Tavana; Barbara Mohebbi; Dennis T. Kennedy
The total quality index (TQI) proposed in this study is an information technology-supported benchmarking tool that helps managers assess a total quality management program by enabling the cost-effective measurement of key organizational processes. TQI utilizes the analytic hierarchy process and the Delphi technique to measure ideal and actual quality management along eight critical factors synthesized by Saraph et al. and
Total synthesis of bryostatin 9.
Wender, Paul A; Schrier, Adam J
The total synthesis of bryostatin 9 was accomplished using a uniquely step-economical and convergent Prins-driven macrocyclization strategy. At 25 linear and 42 total steps, this is currently the most concise and convergent synthesis of a potent bryostatin. PMID:21618969
Total Synthesis of Bryostatin 9
Wender, Paul A.; Schrier, Adam J.
The total synthesis of bryostatin 9 was accomplished using a uniquely step economical and convergent Prins-driven macrocyclization strategy. At 25 linear and 42 total steps, this is currently the most concise and convergent (5 steps post fragment coupling) synthesis of a potent bryostatin. PMID:21618969
Autonoma de Madrid, Universidad
ORGANIZACION DE EMPRESAS 1 6 7 24 CIENCIA POLITICA Y RELACIONES INTERNACIONALES 1 6 DERECHO PRIVADO, SOCIAL Y PATOLOGICA 2 4 ANATOMIA, HISTOLOGIA Y NEUROCIENCIA 8 12 BIOQUIMICA 38 54 CIRUGIA 13 27 FARMACOLOGIA Y AnatomĒa, HistologĒa y Neurociencia 1 1 TOTAL MEDICINA 118 84 PsicologĒa Biol¾gica y de la Salud 2 2 TOTAL
Implant based differences in adverse local tissue reaction in failed total hip arthroplasties: a morphological and immunohistochemical study
Background Adverse local tissue reaction (ALTR) is characterized by periprosthetic soft tissue inflammation composed of a mixed inflammatory cell infiltrate, extensive soft tissue necrosis, and vascular changes. Multiple hip implant classes have been reported to result in ALTR, and clinical differences may represent variation in the soft tissue response at the cellular and tissue levels. The purpose of this study was to describe similarities and differences in periprosthetic tissue structure, organization, and cellular composition by conventional histology and immunohistochemistry in ALTR resulting from two common total hip arthroplasty (THA) implant classes. Methods Consecutive patients presenting with ALTR from two major hip implant classes (N?=?54 patients with Dual-Modular Neck implant; N?=?14 patients with Metal-on-Metal implant) were identified from our prospective Osteolysis Tissue Database and Repository. Clinical characteristics including age, sex, BMI, length of implantation, and serum metal ion levels were recorded. Retrieved synovial tissue morphology was graded using light microscopy and cellular composition was assessed using immunohistochemistry. Results Length of implantation was shorter in the DMN group versus MoM THA group (21.3 [8.4] months versus 43.6 [13.8] months respectively; p?0.005) suggesting differences in implant performance. Morphologic examination revealed a common spectrum of neo-synovial proliferation and necrosis in both groups. Macrophages were more commonly present in diffuse sheets (Grade 3) in the MoM relative to DMN group (p?=?0.016). Perivascular lymphocytes with germinal centers (Grade 4) were more common in the DMN group, which trended towards significance (p?=?0.066). Qualitative differences in corrosion product morphology were seen between the two groups. Immunohistochemistry showed features of a CD4 and GATA-3 rich lymphocyte reaction in both implants, with increased ratios of perivascular T-cell relative to B-cell markers in the DMN relative to the MoM group (p?=?0.032). Conclusion Our results demonstrate that both implant classes display common features of neo-synovial proliferation and necrosis with a CD4 and GATA-3 rich inflammatory infiltrate. Qualitative differences in corrosion product appearance, macrophage morphology, and lymphocyte distributions were seen between the two implant types. Our data suggests that ALTR represents a histological spectrum with implant-based features. PMID:25242891
Totally Magic Graphs Geoffrey Exoo
McSorley, John
~(x). Various authors have introduced labelings that generalize the idea of a magic square, by requiring Totally Magic Graphs Geoffrey Exoo taking the vertices and edges onto the integers 1, 2, . .,.v +e. Such a lab* *eling is vertex magic
Fracture After Total Hip Replacement
... American Academy of Orthopaedic Surgeons. Ģ Dislocation Ģ Limb length inequality Ģ Poor fracture healing Ģ Repeat fracture Ģ Lack of in- ... Surgeons (AAOS). To learn more about your orthopaedic health, please visit orthoinfo.org. Fracture A er Total ...
Maxwell, Bruce D.
and Infectious Diseases 1 1 4 3 2 11 0 25 33 18.2 4 8 11 54 16 21 114 Total College % Women 20.2 College of Arts and Architecture Architecture 1 1 7 2 2 13 0 33 33 15.4 Art 1 1 2 3 4 2 13 25 20 50 30.8 3 5 9 17 11 9 54 Total College % Women 31.5 College
Totally Magic Graphs Geoffrey Exoo
McSorley, John
. For example, the weight of vertex x under the total labeling is wt(x) = (x) + yx (xy), while wt(xy) = (x is a vertex magic total labeling of G. Then the sum of all vertex weights is hv = xV (x) + 2 yE (y) = (1 + 2+e. Such a labeling is vertex magic if the sum of the label on a vertex and the labels on its incident edges
Total patellar skin loss from cryotherapy after total knee arthroplasty.
Dundon, John M; Rymer, Michael C; Johnson, Ron M
The use of cryotherapy after total knee arthroplasty is a very common therapeutic adjunct accepted as routine postoperative care. We present 2 cases of total patellar skin loss due to cryotherapy after total knee arthroplasty. Substantial soft tissue defects were created after the initial debridement of the necrotic tissue. Both patients were evaluated for frostbite, and the wounds were sharply debrided. Application of an advanced wound management technique involves the use of a collagen-glycosaminoglycan biodegradable bilayer matrix, silver impregnated antimicrobial dressing, and low-pressure vacuum device, followed by delayed split thickness skin grafting and low-pressure vacuum device. We find that this technique provided durable soft tissue coverage for necrotic wounds of the knee that do not involve the joint capsule. PMID:22749659
Oiled Pending Loggerhead Kemp's Ridley Green Date Nest Totals Loggerhead Kemp's Ridley Green Date 19 319 272 1145 396 271 4 3 278 14235 125 316 14676 Overall Totals Turtles - Translocation of Gulf Totals TOTAL Turtles Dead 9 99 0 TOTAL Other CetaceaTOTAL Dolphins Live Date Totals Live Dead Released
Total relationship management (TRM) and total quality management (TQM)
Mosad Zineldin
Companies operate and compete in a highly and aggressive global climate. This climate has led to an increased emphasis on quality. TQM focuses on the integration and co-ordination, as well as on the continuous improvement of all activities and processes. Total relationship management (TRM) is a very recent marketing strategy and philosophy. It focuses on and is concerned with all
Total Quality Management Is Total at Fox Valley Technical College.
ERIC Educational Resources Information Center
Tyler, Carol R.
At Fox Valley Technical College (Wisconsin), application of Total Quality Management (TQM) brought positive outcomes and other effects. Areas in which TQM was used are considered, including admissions, employee safety, customer focus, policy formation, management performance appraisal, student services, creation of a self-managing class, TQM forģ
Total Quality in Higher Education. Total Quality Series.
ERIC Educational Resources Information Center
Lewis, Ralph G.; Smith, Douglas H.
This volume offers a detailed argument for and description of Total Quality Management (TQM) for institutions of higher education. Chapter 1 elaborates on why TQM is good for higher education and includes some warning as to why implementation at colleges and universities may not be easy. Chapter 2 provides an overview of the history of the TQMģ
Total synthesis of (+)-madangamine D.
Ballette, Roberto; Pķrez, Maria; Proto, Stefano; Amat, Mercedes; Bosch, Joan
Madangamines are a group of bioactive marine sponge alkaloids, embodying an unprecedented diazapentacyclic skeletal type. The enantioselective total synthesis of madangamine?D has been accomplished, and represents the first total synthesis of an alkaloid of the madangamine group. It involves the stereoselective construction of the diazatricyclic ABC core using a phenylglycinol-derived lactam as the starting enantiomeric scaffold and the subsequent assembly of the peripheral macrocyclic rings. The synthesis provides, for the first time, a pure sample of madangamine?D and confirms the absolute configuration of this alkaloid family. PMID:24798407
Zirker, J B
Total eclipses of the sun offer research opportunities in a variety of sciences. Some of the advances in solar physics resulting from eclipse observations are discussed. Experiments at the total eclipse of 16 February 1980 in India are also described. These included a test of general relativity, studies in coronal physics, investigations of solar prominences, diameter measurements, a search for interplanetary dust, a study of the gravity waves in the earth's atmosphere, and experiments on the biological effects on animals and humans. PMID:17817829
Sport after total hip arthroplasty
L. Dubs; N. Gschwend; U. Munzinger
Up to now, sporting activity after total hip arthroplasty has been limited or terminated completely because of the risk of failure. In the case of younger patients, it is desirable to know whether this attitude is justified. Consequently, an analysis has been made of 110 patients (all male, average age at the time of the operation 55 years, 42 bilateral).
Total Synthesis of (▒)-Maoecrystal V
Peng, Feng; Danishefsky, Samuel J.
The total synthesis of racemic maoecrystal V has been accomplished. Key steps include an intramolecular Diels-Alder cyclization to rapidly construct the core system from simple starting materials and the creation of the A¢C ring trans-fusion through intramolecular delivery of a hydrogen to the hindered ?-face of the ring system. PMID:23126440
Total Synthesis of Propolisbenzofuran Bå
Jones, Brian T.; Avetta, Christopher T.; Thomson, Regan J.
The first total synthesis of propolisbenzofuran B, a bioactive natural product isolated from honeybee propolis resin, is reported. The convergent synthesis makes use of a silicon-tether controlled oxidative ketone¢ketone cross-coupling and a novel benzofuran-generating cascade reaction to deliver the core structure of the natural product from readily prepared precursors. PMID:24976944
Economics of total quality management
Phillip J. Lederer; Seung-Kyu Rhee
This paper presents two models of the economics of total quality management. In the first, the concept of quality management is viewed as a technological innovation that requires investment. To reduce cost and improve quality, firms must make investments that are largely sunk. The effect of market competition on quality related technology investments is studied. Several results follow. With new
Total internal reflectance optoacoustic spectroscopy
P. R. Muessig; G. J. Diebold
When radiation undergoes total internal reflection at a solid¢gas interface, an exponentially decaying wave, known as the evanescent wave, propagates into the gas. If the incident radiation is amplitude modulated and the gas has an absorption at the wavelength of the radiation, the optoacoustic effect can be produced by absorption of energy from the evanescent wave. Experiments with 10.6 ?
Total internal reflectance optoacoustic spectroscopy
P. R. Muessig; G. J. Diebold
When radiation undergoes total internal reflection at a solid--gas interface, an exponentially decaying wave, known as the evanescent wave, propagates into the gas. If the incident radiation is amplitude modulated and the gas has an absorption at the wavelength of the radiation, the optoacoustic effect can be produced by absorption of energy from the evanescent wave. Experiments with 10.6 ..mu..
Enantioselective total synthesis of (-)-laurenditerpenol.
Pitsinos, Emmanuel N; Athinaios, Nikolaos; Vidali, Veroniki P
A highly convergent total synthesis of (-)-laurenditerpenol has been accomplished through an organolithium to aldehyde nucleophilic addition. Preparation of the prerequisite key intermediates in optically pure form was based on an improved, short, and efficient synthesis of "wine lactone" from (S)-limonene and Corey's catalytic enantioselective Diels-Alder reaction of 2,5-dimethyl furan with diethyl fumarate. PMID:22905649
Total hydrocarbon analyzer evaluation study
N. Shamat; E. Crumpler; A. Roddan
Measuring and controlling organic emissions from incineration processes has become a major environmental concern in recent years. The US Environmental Protection Agency (EPA) recently proposed a regulation for sewage sludge incinerators under section 405(d) of the Clean Water Act that will require all sludge incinerators to monitor total hydrocarbon emissions (THCs) on a continuous basis. Such a requirement would be
Total synthesis of lysergic acid.
Umezaki, Satoshi; Yokoshima, Satoshi; Fukuyama, Tohru
A total synthesis of lysergic acid was accomplished. Key features of our synthesis include stereoselective construction of the stereogenic centers at the allylic positions by using the Evans aldol reaction, and a sequential process with a ring-closing metathesis and an intramolecular Heck reaction to construct the C and D rings. PMID:23919892
Total Synthesis of (¢)-Nakadomarin A
Nilson, Mark G.; Funk, Raymond L.
A concise diastereoselective total synthesis of (¢)-nakadomarin A has been completed in 21 steps from D-pyroglutamic acid. Key steps include an enecarbamate Michael addition/furan-N-acyliminium ion cascade cyclization to provide the tetracyclic core, and ring-closing alkyne and alkene metatheses to construct the 15- and 8-membered azacycles, respectively. PMID:20932022
Total Quality Management in Education.
ERIC Educational Resources Information Center
Johnson, James H.
Ways to apply the concepts and processes of Total Quality Management (TQM) to education are discussed in this document. Following the introduction and the preface, chapter 1 provides a historical overview and describes the four cornerstones of TQM--an understanding of systems, psychology, knowledge, and statistics. Chapter 2 describes some of theģ
What is Total Quality Management?
ERIC Educational Resources Information Center
Bryan, William A.
Provides a general overview of Total Quality Management (TQM) and explains why there is pressure for change in higher education institutions. Defines TQM and the various themes, tools, and beliefs that make it different from other management approaches. Presents 14 principles and how they might be applied to student affairs. (RJM)
Total claviculectomy for pathological fractures.
Spar, I
Two patients with pathological fractures of the clavicle were treated by total claviculectomy with relief of symptoms. Subsequent drooping of the shoulder with mild weakness of the affected upper extremity seems related to the loss of normal arcuate shoulder motion that is dependent upon the yardarm function of the clavicle. PMID:608283
The results of total claviculectomy.
Wood, V E
Five cases of total claviculectomy are described to demonstrate that the functional results are excellent. A review of the literature supports the concept that the clavicle is an accessory to the body skeleton and that patients can function well without its bony support. The exception is dysfunction of the trapezius. PMID:3720083
Total synthesis of clavatadine A.
Conn, Stephanie J; Vreeland, Shannon M; Wexler, Alexandra N; Pouwer, Rebecca N; Quinn, Ronald J; Chamberland, Stephen
The first total synthesis of the potent and selective human blood coagulation factor XIa inhibitor clavatadine A (1) is described. Direct, early-stage guanidinylation enabled rapid, convergent access to an immediate clavatadine A precursor. Concomitant lactone hydrolysis and guanidine deprotection with aqueous acid cleanly provided clavatadine A (1) in only four steps (longest linear sequence, 41-43% overall yield). PMID:25517413
Curare drugs and total paralysis
Kendon Smith
Question is raised concerning the efficacy of curare drugs in producing total striate paralysis. It is pointed out that early Es reported muscular activity under deep curarization; and that thinking, quite possibly muscular in nature, is unhampered by curarization. It is further suggested that the \\
Total Antioxidant Capacity of Fruits
Hong Wang; Guohua Cao; Ronald L. Prior
The total antioxidant activity of 12 fruits and 5 commercial fruit juices was measured in this study using automated oxygen radical absorbance capacity (ORAC) assay. On the basis of the wet weight of the fruits (edible portion), strawberry had the highest ORAC activity (micromoles of Trolox equivalents per gram) followed by plum, orange, red grape, kiwi fruit, pink grapefruit, white
Total quality control in education
Zhongming Liang
Some quality problems in American higher education are addressed. The author suggests that the concept of total quality control (TQC), a philosophy in manufacturing management, be applied to education in order to achieve changes from a more individualized control to a more systemized control. He discusses some particular methods for TQC in teaching. He suggests team work for course content
Energy Planning: A Total Concept.
ERIC Educational Resources Information Center
Hall, Stephen S. J.
Harvard's energy conservation plan is presented in detail with the hope that it will suggest practical, cost-effective energy-saving ideas to other institutions, and to dispel frequently-expressed fears concerning the feasibility and acceptance problems of this type of program. The total energy plan incorporates numerous specific elements thatģ
Autonoma de Madrid, Universidad
DESARROLLO 2 4 FINANCIACION E INVESTIGACION COMERCIAL 2 ORGANIZACION DE EMPRESAS 2 6 8 18 CIENCIA POLITICA Y NEUROCIENCIA 2 4 BIOQUIMICA 15 28 CIRUGIA 7 15 FARMACOLOGIA Y TERAPEUTICA 1 1 FISIOLOGIA 1 MEDICINA 13 20 19 AnatomĒa, HistologĒa y Neurociencia 1 1 Medicina 44 25 FarmacologĒa y Terapķutica 19 17 TOTAL
Total Synthesis of (?)-Calyciphylline N
Shvartsbart, Artem; Smith, Amos B.
The total synthesis of the architecturally complex Daphniphyllum alkaloid (?)-calyciphylline N has been achieved. Highlights of the synthesis include a Et2AlCl promoted, highly stereoselective susbtrate controlled intramolecular Diels-Alder reaction, a transannular enolate alkylation, an effective Stille carbonylation/Nazarov cyclization sequence, and a high risk dia-stereoselective hydrogenation of a fully substituted conjugated diene ester. PMID:24319987
Complications of total parenteral nutrition
James P Knochel
Continued technological improvements in the quality of nutritional formulations and techniques for parenteral administration have resulted in a major improvement in patient care. The ability to provide all necessary nutrients by intravenous infusion, so-called total parenteral nutrition (TPN), has sustained life and growth in patients who otherwise would have died. Most adult patients who derive benefit from this procedure are
Facile total synthesis of xanthorrhizol.
Du, Zhenting; Wang, Yin; Ma, Weili; Lv, Dong; Yu, Hongrui
A facile total synthesis of the bisabolane sesquiterpene, xanthorrhizol (1), has been achieved in 6 steps, in 48% overall yield. The starting material was 3-methoxy-4-methyl-phenoacetone (7), and a Claisen-Johnson rearrangement was used as the key step to construct the skeleton of the target molecule. PMID:21425666
Designing with Systemic Total Quality.
ERIC Educational Resources Information Center
Callaos, Nagib; Callaos, Belkis
Discusses conceptual frameworks for the designing process, including conclusion-oriented design and decision-oriented design; describes the systemic quality cube of design that incorporates process, product, efficiency, and effectiveness and considers total, global, and systemic quality; and discusses present applications, including computerizedģ
Total synthesis of (+)-papulacandin D
Scott E. Denmark; Tetsuya Kobayashi; Christopher S. Regens
A total synthesis of (+)-papulacandin D has been achieved in 31 steps, in a 9.2% overall yield from commercially available materials. The synthetic strategy divided the molecule into two nearly equal sized subunits, the spirocyclic C-arylglycopyranoside and the polyunsaturated fatty acid side-chain. The C-arylglycopyranoside was prepared in 11 steps in a 30% overall yield from triacetoxyglucal. The fatty acid side-chain
Total occipitalization of the atlas
Mohamed Akram Al-Motabagani; Manjappa Surendra
Occipitalization of the atlas is an important congenital malformation of the craniovertebral region because of the proximity\\u000a to the spinomedullary region. In a sample of 109 human adult skulls of Asian origin examined for evidence of atlanto-occipital\\u000a fusion, only one specimen exhibited this type of anomaly, in which the atlas was totally synostosed with the occipital bone\\u000a with multiple bony
First total synthesis of ocimarin
Jin Hui Yang; Yun Feng Li; Cong Bin Ji; Shi Zhi Jiang; Wan Yi Liu
A facile approach for the first synthesis of ocimarin, naturally occurring coumarins, was developed by employing a cerium (III) chloride heptahydrate-catalyzed Pechmann condensation of phenols and ?-keto esters in a solvent-free system as key step, by which ocimarin was achieved by three steps starting from acetylacetic ether and resorcinol with total yield 23.2%. All structures of new compounds were confirmed
A totally transparent alignment sensor
Jorge Moromisato et al.
We describe the development of a totally transparent CCD based optical beam position sensing device that can measure transverse displacements with an accuracy of a few microns at a distance of many meters. The device includes on sensor DSP processing of the signal spectra with background subtraction and calibration to produce a compressed beam position, sensor address/status readout in token serial strings of sensors. The position monitoring system for the CMS Endcap Muon detector is presented as an intended application.
Total thyroidectomy: Complications and technique
Jay K. Harness; Lit Fung; Norman W. Thompson; Richard E. Burney; Michael K. McLeod
During the 27-year period from 1957 to 1984, four hundred thirty patients underwent total thyroidectomies for malignant or benign disease of the thyroid gland at our institutions. Thyroid cancer was found in 83.4% of cases, and 47.2% of these had concomitant lymph node dissections. Transient recurrent laryngeal nerve injury occurred in 6.2% of the entire series. Permanent unilateral vocal cord
Acceleration using total internal reflection
Fernow, R.C.
This report considers the use of a dielectric slab undergoing total internal reflection as an accelerating structure for charged particle beams. We examine the functional dependence of the electromagnetic fields above the surface of the dielectric for polarized incident waves. We present an experimental arrangement for testing the performance of the method, using apparatus under construction for the Grating Acceleration experiment at Brookhaven National Laboratory. 13 refs., 4 figs., 2 tabs.
Total anomalous pulmonary venous connection
Roger W. Byard; John D. Gilbert
Total anomalous pulmonary venous connection (TAPVC), where the pulmonary venous circulation drains into the systemic venous\\u000a circulation rather than into the left atrium, may present a number of problems at autopsy. A 5-week-old infant is reported\\u000a who died suddenly and unexpectedly who was found at autopsy to have infradiaphragmatic TAPVC into the portal vein. The only\\u000a associated anomalies were a
Deformation of the Durom Acetabular Component and Its Impact on Tribology in a Cadaveric ModelŚA Simulator Study
Gu, Yanqing; Wang, Qing; Cui, Weiding; Fan, Weimin
Background Recent studies have shown that the acetabular component frequently becomes deformed during press-fit insertion. The aim of this study was to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the Durom large head metal-on-metal (MOM) total hips in simulators. Methods Six Durom cups impacted into reamed acetabula of fresh cadavers were used as the experimental group and another 6 size-paired intact Durom cups constituted the control group. All 12 Durom MOM total hips were put through a 3 million cycle (MC) wear test in simulators. Results The 6 cups in the experimental group were all deformed, with a mean deformation of 41.78▒8.86 Ąm. The average volumetric wear rate in the experimental group and in the control group in the first million cycle was 6.65▒0.29 mm3/MC and 0.89▒0.04 mm3/MC (t?=?48.43, p?=?0.000). The ion levels of Cr and Co in the experimental group were also higher than those in the control group before 2.0 MC. However there was no difference in the ion levels between 2.0 and 3.0 MC. Conclusions This finding implies that the non-modular acetabular component of Durom total hip prosthesis is likely to become deformed during press-fit insertion, and that the deformation will result in increased volumetric wear and increased ion release. Clinical Relevance This study was determined to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the prosthesis. Deformation of the cup after implantation increases the wear of MOM bearings and the resulting ion levels. The clinical use of the Durom large head prosthesis should be with great care. PMID:23144694
Total synthesis of zoanthamine alkaloids.
Yoshimura, Fumihiko; Tanino, Keiji; Miyashita, Masaaki
Zoanthamine alkaloids, isolated from organisms in the Zoanthus genus, constitute a distinctive family of marine metabolites. These molecules exhibit a broad spectrum of unique biological properties. For example, norzoanthamine inhibits interleukin-6, the key mediator of bone resorption in osteoporosis, providing a promising drug candidate for a disease that affects more than 10 million people over age 50 in the United States. In addition, these natural products are characterized by a densely functionalized heptacyclic framework, as exemplified by the structures of zoanthamine, norzoanthamine, and zoanthenol, which makes them extremely attractive targets for chemical synthesis. Prior to our first total synthesis of norzoanthamine in 2004, the densely functionalized and complex stereostructures of the zoanthamine alkaloids had impeded synthetic studies of these molecules. In this Account, we describe our synthetic approach toward the total synthesis of zoanthamine alkaloids, focusing on how we overcame various synthetic challenges. At the beginning of our synthetic studies, we aimed to develop an efficient route that was flexible enough to provide access to several members of the family while allowing the synthesis of various analogues for biological testing. Our first project was the total synthesis of norzoanthamine, and we established an efficient synthetic route based on a novel strategy involving the following key features. First, we used a sequential three-component coupling reactions and subsequent photosensitized oxidation of a furan moiety to synthesize the precursor for the key intramolecular Diels-Alder reaction. Second, the key intramolecular Diels-Alder reaction constructed the ABC-ring carbon framework bearing two adjacent quaternary asymmetric carbon atoms at the C12 and C22 positions in a single stereoselective step. Third, we installed the third quaternary asymmetric carbon center at the C9 position by an intramolecular acylation of a keto alcohol followed by successive O-methylation and C-methylation reactions with complete stereoselectivity. Through the exploitation of a deuterium kinetic isoptope effect, we then efficiently synthesized the alkyne segment. Next, a coupling reaction between the alkyne segment and the amino alcohol segment and several subsequent synthetic transformations afforded the bis-aminoacetalization precursor. Finally, bis-aminoacetalization reactions carried out in one-pot constructed the DEFG-ring system and culminated in the total synthesis of norzoanthamine. Our synthetic route to norzoanthamine also allowed access to other zoanthamine alkaloids from a common synthetic intermediate, by way of stereoselective introduction of the C19 methyl group for zoanthamine, and isoaromatization for construction of the aromatic A-ring in zoanthenol. The chemistry described here not only allowed us to overcome formidable synthetic challenges but also opened a completely chemical avenue to naturally occurring zoanthamine alkaloids and their synthetic derivatives. PMID:22340011
The total synthesis of (-)-nitidasin.
Hog, Daniel T; Huber, Florian M E; Mayer, Peter; Trauner, Dirk
Nitidasin is a pentacyclic sesterterpenoid with a rare 5-8-6-5 carbon skeleton that was isolated from the Peruvian folk medicine "Hercampuri". It belongs to a small class of sesterterpenoids that feature an isopropyl trans-hydrindane moiety fused to a variety of other ring systems. As a first installment of our general approach toward these natural products, we report the total synthesis of the title compound. Our stereoselective, convergent route involves the addition of a complex alkenyl lithium compound to a trans-hydrindanone, followed by chemoselective epoxidation, ring-closing olefin metathesis, and redox adjustment. PMID:24962933
[Total parenteral nutrition in surgery].
Sirovich, M G; Ruotolo, F; Andrich, R; del Vecchio, T
Following a number of general remarks regarding the metabolic physiopathology of the surgical patient, the indications and biochemical premises for total parenteral nutrition are examined. Stress is also labor, on problems of administration routes and modalities and on the chemico-clinical controls needed to weigh up the technique. Finally, the results of personal experience in the treatment of 16 patients whose prevalent pathology consist of necrotico-haemorrhagic A.P. and its sequelae are reported. The usefulness of the technique is confirmed because it offers interesting results in difficult and often dramatic surgical situations. PMID:117402
Brannan, K M
Quality is at the top of American consumers' demand list, and consequently American manufacturing companies have been forced to assign priority to the development of high-quality products. To improve the quality of what they offer, many manufacturers use the management philosophy known as total quality management (TQM), and now the service sector is following in their footsteps. The health care industry is a good example of a service industry that can benefit greatly from TQM, and it is the purpose of this article to show how a health care provider can implement TQM and evaluate its effects. PMID:10178544
Total synthesis of heronapyrrole C.
Ding, Xiao-Bo; Furkert, Daniel P; Capon, Robert J; Brimble, Margaret A
A flexible total synthesis of the 2-nitropyrrole-derived marine natural product, (+)-heronapyrrole C, is reported. The approach is based on regioselective access to key building blocks containing the rare 4-substituted 2-nitropyrrole motif. Sharpless asymmetric epoxidation and dihydroxylation and a Shi epoxidation were used to introduce the five stereogenic centers of the bis-THF-diol side chain. The N-benzoyloxymethyl (Boz) protecting group was crucial for functionalization of the 2-nitropyrrole moiety and enabling final deprotection under mild conditions. PMID:24351092
Oiled Not Visibly Oiled Pending Loggerhead Kemp's Ridley Green Date Nest Totals Loggerhea d Kemp Totals TOTAL Other CetaceaTOTAL Dolphins Live Date Totals Live Dead Released 13 154 Turtles Turtles Dead # of Nests Translocated #12;Weekly Changes Page 1 of 1 Visibly Oiled Not Visibly Oiled
NASA Astrophysics Data System (ADS)
Jeynes, C.; Bailey, M. J.; Bright, N. J.; Christopher, M. E.; Grime, G. W.; Jones, B. N.; Palitsin, V. V.; Webb, R. P.
The suite of techniques which are available with the small accelerators used for MeV ion beam analysis (IBA) range from broad beams, microbeams or external beams using the various particle and photon spectrometries (including RBS, EBS, ERD, STIM, PIXE, PIGE, NRA and their variants), to tomography and secondary particle spectrometries like MeV-SIMS. These can potentially yield almost everything there is to know about the 3-D elemental composition of types of samples that have always been hard to analyse, given the sensitivity and the spacial resolution of the techniques used. Molecular and chemical information is available in principle with, respectively, MeV-SIMS and high resolution PIXE. However, these techniques separately give only partial information - the secret of "Total IBA" is to find synergies between techniques used simultaneously which efficiently give extra information. We here review how far "Total IBA" can be considered already a reality, and what further needs to be done to realise its full potential.
Hyperglycemia During Total Parenteral Nutrition
Pasquel, Francisco J.; Spiegelman, Ronnie; McCauley, Megan; Smiley, Dawn; Umpierrez, Denise; Johnson, Rachel; Rhee, Mary; Gatcliffe, Chelsea; Lin, Erica; Umpierrez, Erica; Peng, Limin; Umpierrez, Guillermo E.
OBJECTIVE To determine the effect of total parenteral nutrition (TPN)-induced hyperglycemia on hospital outcome. RESEARCH DESIGN AND METHODS The study determined whether blood glucose values before, within 24 h, and during days 2¢10 of TPN are predictive of hospital complications and mortality. RESULTS Subjects included a total of 276 patients receiving TPN for a mean duration of 15 ▒ 24 days (▒SD). In multiple regression models adjusted for age, sex, and diabetes status, mortality was independently predicted by pre-TPN blood glucose of 121¢150 mg/dl (odds ratio [OR] 2.2, 95% CI 1.1¢4.4, P = 0.030), 151¢180 mg/dl (3.41, 1.3¢8.7, P = 0.01), and >180 mg/dl (2.2, 0.9¢5.2, P = 0.077) and by blood glucose within 24 h of >180 mg/dl (2.8, 1.2¢6.8, P = 0.020). A blood glucose within 24 h of >180 mg/dl was associated with increased risk of pneumonia (OR 3.1, 95% CI 1.4¢7.1) and acute renal failure (2.3, 1.1¢5.0). CONCLUSIONS Hyperglycemia is associated with increased hospital complications and mortality in patients receiving TPN. PMID:20040658
Solar total energy project Shenandoah
This document presents the description of the final design for the Solar Total Energy System (STES) to be installed at the Shenandoah, Georgia, site for utilization by the Bleyle knitwear plant. The system is a fully cascaded total energy system design featuring high temperature paraboloidal dish solar collectors with a 235 concentration ratio, a steam Rankine cycle power conversion system capable of supplying 100 to 400 kW(e) output with an intermediate process steam take-off point, and a back pressure condenser for heating and cooling. The design also includes an integrated control system employing the supervisory control concept to allow maximum experimental flexibility. The system design criteria and requirements are presented including the performance criteria and operating requirements, environmental conditions of operation; interface requirements with the Bleyle plant and the Georgia Power Company lines; maintenance, reliability, and testing requirements; health and safety requirements; and other applicable ordinances and codes. The major subsystems of the STES are described including the Solar Collection Subysystem (SCS), the Power Conversion Subsystem (PCS), the Thermal Utilization Subsystem (TUS), the Control and Instrumentation Subsystem (CAIS), and the Electrical Subsystem (ES). Each of these sections include design criteria and operational requirements specific to the subsystem, including interface requirements with the other subsystems, maintenance and reliability requirements, and testing and acceptance criteria. (WHK)
Faster GW total energy calculations
NASA Astrophysics Data System (ADS)
Handlin, Mzuri; Govoni, Marco; Galli, Giulia
Accurate calculations of total energies are necessary for understanding and predicting material properties. Currently density functional theory is the most widely used method for condensed systems, but in most cases it cannot accurately treat systems with dispersion interactions. Many body perturbation theory within, e.g. the GW approximation (GW), may in principle treat dispersion interactions accurately, but at a high computational cost. A major bottleneck of standard GW calculations is the required storage and inversion of large dielectric matrices, as well as the determination of their frequency dependence; the recently developed projective dielectric eigenpotential (PDEP) algorithm together with Lanczos based techniques avoid these problems by using a spectral decomposition of the dielectric matrix. We generalized the PDEP algorithm to efficiently compute GW total energies and we will present results for the energies of molecular crystals and solids of nanoparticles. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences under Award Number DE-FG02-06ER46262.
Total synthesis of maoecrystal V.
Zhang, Wei-Bin; Lin, Guang; Shao, Wen-Bin; Gong, Jian-Xian; Yang, Zhen
Maoecrystal V (1) is a novel diterpenoid, which was originally isolated from the leaves of the Chinese medicinal herb Isodon eriocalyx in 2004 by Sun et?al.1 It has been found to be selectively cytotoxic towards HeLa cells, with an IC50 value of 20?ng?mL(-1) . Significant research efforts have been devoted to the synthesis of maoecrystal V because of its intriguing biological properties, rarity in nature, and complex structural features. Herein, we describe our recent investigations, which have culminated in the total synthesis of (▒)-maoecrystal V. The current strategy involved three key steps for the successful construction of the key tetrahydrofuran oxa-bridge skeleton, including a Wessely oxidative dearomatization, a novel intramolecular Diels-Alder reaction, and a Rh(II) -catalyzed O - H insertion reaction. PMID:25504983
Total synthesis of bryostatin 1.
Keck, Gary E; Poudel, Yam B; Cummins, Thomas J; Rudra, Arnab; Covel, Jonathan A
Bryostatin 1 is a marine natural product that is a very promising lead compound because of the potent biological activity it displays against a variety of human disease states. We describe herein the first total synthesis of this agent. The synthetic route adopted is a highly convergent one in which the preformed, heavily functionalized pyran rings A and C are united by "pyran annulation", the TMSOTf-promoted reaction between a hydroxyallylsilane appended to the A-ring fragment and an aldehyde contained in the C-ring fragment, with concomitant formation of the B ring. Further elaborations of the resulting very highly functionalized intermediate include macrolactonization and selective cleavage of just one of five ester linkages present. PMID:21175177
Total Synthesis of Bryostatin 1
Keck, Gary E.; Poudel, Yam B.; Cummins, Thomas J.; Rudra, Arnab; Covel, Jonathan A.
Bryostatin 1 is a marine natural product that is a very promising lead compound due to the potent biological activity it displays against a variety of human disease states. We describe herein the first total synthesis of this agent. The synthetic route adopted is a highly convergent one in which preformed and heavily functionalized pyran rings A and C are united by ōpyran annulationö: the TMSOTf promoted reaction between a hydroxy allylsilane appended to the A ring fragment and an aldehyde contained in the C ring fragment, with concomitant formation of the B ring. Further elaborations of the resulting very highly functionalized intermediate include macrolactonization and selective cleavage of just one of five ester linkages present. PMID:21175177
Total internal reflectance optoacoustic spectroscopy
Muessig, P.R.; Diebold, G.J.
When radiation undergoes total internal reflection at a solid--gas interface, an exponentially decaying wave, known as the evanescent wave, propagates into the gas. If the incident radiation is amplitude modulated and the gas has an absorption at the wavelength of the radiation, the optoacoustic effect can be produced by absorption of energy from the evanescent wave. Experiments with 10.6 ..mu.. radiation internally reflected in an NaCl prism show the amplitude of the optoacoustic signal (in SF/sub 6/) to be linearly proportional to the product of the square of the electric field amplitude and the penetration depth of the evanescent wave as given by Fresnel's equations. The amplitude of the optoacoustic signal in a 100-..mu..l detection cell is found to increase linearly with the mole fraction of SF/sub 6/ in He over the range from 10/sup -5/ to 10/sup -2/.
Total Maximum Daily Load Program
NSDL National Science Digital Library
The Environmental Protection Agency (EPA) provides this informative resource on Total Maximum Daily Loads (TMDL). A term used to discuss water quality, TMDL refers to "a calculation of the maximum amount of a pollutant that a water body can receive and still meet water quality standards." The TMDL Program Website offers background information on TMDLs (including FAQs), a National Overview of Impaired Waters in the US, and two standard presentations on TMDLs (HTML and Power Point). The heart of the site, however, is the interactive map of the US, which allows users access to each state's TMDL Program. Within each state, watershed names and maps, as well as source information (Water body, Parameter of Concern, Priority for TMDL Development), are provided.
Total synthesis of (+)-lysergic acid.
Liu, Qiang; Zhang, Yu-An; Xu, Ping; Jia, Yanxing
We report the enantioselective total synthesis of (+)-lysergic acid using two different strategies, which featured three metal-catalyzed reactions for the construction of the BCD three rings, involving Pd-catalyzed indole synthesis for the construction of the B ring, a ring-closing metathesis reaction for the formation of the D ring, and an intramolecular Heck reaction to forge the C ring. In synthetic strategy I, the synthesis was achieved in 20 steps following the ring construction sequence of BDC. In synthetic strategy II, the synthetic route was shortened to only 12 steps by following the ring construction sequence of DBC and using a 4-chlorotryptophan derivative for the intramolecular Heck reaction. Moreover, we also discussed an unsuccessful synthetic strategy. PMID:24111583
Formal total synthesis of aliskiren.
Peters, Byron K; Liu, Jianguo; Margarita, Cristiana; Andersson, Pher G
The efficient and selective formal total synthesis of aliskiren is described. Aliskiren, a renin inhibitor drug, has received considerable attention, primarily because it is the first of the renin inhibitor drugs to be approved by the FDA. Herein, the formal synthesis of aliskiren by iridium-catalyzed asymmetric hydrogenation of two allylic alcohol fragments is reported. Screening a number of N,P-ligated iridium catalysts yielded two catalysts that gave the highest enantioselectivity in the hydrogenation, which gave the saturated alcohols in 97 and 93?% ee. In only four steps after hydrogenation, the fragments were combined by using the Julia-Kocienski reaction to produce late-stage intermediate in an overall yield of 18?%. PMID:25783891
Total internal reflection Raman spectroscopy.
Woods, David A; Bain, Colin D
Total internal reflection (TIR) Raman spectroscopy is an experimentally straightforward, surface-sensitive technique for obtaining chemically specific spectroscopic information from a region within approximately 100-200 nm of a surface. While TIR Raman spectroscopy has long been overshadowed by surface-enhanced Raman scattering, with modern instrumentation TIR Raman spectra can be acquired from sub-nm thick films in only a few seconds. In this review, we describe the physical basis of TIR Raman spectroscopy and illustrate the performance of the technique in the diverse fields of surfactant adsorption, liquid crystals, lubrication, polymer films and biological interfaces, including both macroscopic structures such as the surfaces of leaves, and microscopic structures such as lipid bilayers. Progress, and challenges, in using TIR Raman to obtain depth profiles with sub-diffraction resolution are described. PMID:22003492
Instability following total knee arthroplasty.
Rodriguez-Merchan, E Carlos
Background Knee prosthesis instability (KPI) is a frequent cause of failure of total knee arthroplasty. Moreover, the degree of constraint required to achieve immediate and long-term stability in total knee arthroplasty (TKA) is frequently debated. Questions This review aims to define the problem, analyze risk factors, and review strategies for prevention and treatment of KPI. Methods A PubMed (MEDLINE) search of the years 2000 to 2010 was performed using two key words: TKA and instability. One hundred and sixty-five initial articles were identified. The most important (17) articles as judged by the author were selected for this review. The main criteria for selection were that the articles addressed and provided solutions to the diagnosis and treatment of KPI. Results Patient-related risk factors predisposing to post-operative instability include deformity requiring a large surgical correction and aggressive ligament release, general or regional neuromuscular pathology, and hip or foot deformities. KPI can be prevented in most cases with appropriate selection of implants and good surgical technique. When ligament instability is anticipated post-operatively, the need for implants with a greater degree of constraint should be anticipated. In patients without significant varus or valgus malalignment and without significant flexion contracture, the posterior cruciate ligament (PCL) can be retained. However, the PCL should be sacrificed when deformity exists particularly in patients with rheumatoid arthritis, previous patellectomy, previous high tibial osteotomy or distal femoral osteotomy, and posttraumatic osteoarthritis with disruption of the PCL. In most cases, KPI requires revision surgery. Successful outcomes can only be obtained if the cause of KPI is identified and addressed. Conclusions Instability following TKA is a common cause of the need for revision. Typically, knees with deformity, rheumatoid arthritis, previous patellectomy or high tibial osteotomy, and posttraumatic arthritis carry higher risks of post-operative instability and are indications for more constrained TKA designs. Instability following TKA usually requires revision surgery which must address the cause of the instability for success. PMID:23024625
UNIVERSITY OF HAWAII AT MANOA FACULTY AND STAFF Men Women Total Men Women Total Men Women Total
Wang, Yuqing
UNIVERSITY OF HAWAII AT MANOA FACULTY AND STAFF Men Women Total Men Women Total Men Women Total: December 3, 2012 University of Hawaii at Manoa FTE (fulltime equivalent)Total FullTime Grade Level 37% Office of the Vice Chancellor for Academic Affairs Manoa Institutional Research firstname.lastname@example.com 1
Total synthesis of (-)-4-hydroxyzinowol.
Todoroki, Hidenori; Iwatsu, Masafumi; Urabe, Daisuke; Inoue, Masayuki
(-)-4-Hydroxyzinowol (1) is a potent inhibitor of P-glycoprotein, which has been implicated in multi-drug resistance in the treatment of cancer. The highly oxygenated structure of 1 comprises a trans-decalin (AB-ring) and a tetrahydrofuran (C-ring) and possesses six acyloxy, one hydroxy, and one alkoxy groups. The challenge of synthesizing 1 is particularly heightened by the nine consecutive stereogenic centers on the 10-carbon decalin skeleton. The total synthesis of this extremely complex structure was achieved in 36 steps from 5-acetoxynaphthalen-1-ol by the judicious application of powerful chemo- and stereoselective reactions. The rhodium-catalyzed asymmetric 1,4-addition of the isopropenyl group set the C7-stereocenter, and the remaining three cis-oriented hydroxy groups (C6, 8, and 9) of the B-ring were stereoselectively constructed in a stepwise fashion. The C5-tetra-substituted and C10-quaternary carbons at the juncture of the AB-ring were then introduced by oxidative dearomatization and Diels-Alder reaction, respectively. After acid-promoted formation of the C-ring ether, the C1-, 2-, 4- and 6-oxygen-based functional groups were stereoselectively installed to deliver the fully functionalized tricycle. Finally, the polyhydroxylated structure was converted to the polyacylated target molecule 1 via regioselective acetylation and benzoylation. PMID:25152070
Total hydrocarbon analyzer evaluation study
Shamat, N. (EMA Services, Inc., St. Paul, MN (United States)); Crumpler, E. (Environmental Protection Agency, Washington, DC (United States)); Roddan, A. (Rosemount Analytical Division, La Habra, CA (United States))
Measuring and controlling organic emissions from incineration processes has become a major environmental concern in recent years. The US Environmental Protection Agency (EPA) recently proposed a regulation for sewage sludge incinerators under section 405(d) of the Clean Water Act that will require all sludge incinerators to monitor total hydrocarbon emissions (THCs) on a continuous basis. Such a requirement would be part of National Pollutant Discharge Elimination (NPDES) permits and site-specific THC limits would be established for facilities based on a risk assessment of organic emissions. Before EPA can finalize the proposed requirement, THC monitoring must be successfully conducted in a plant environment and the system required by any final regulation must be kept in operation so that facilities can comply with their permits. The Metropolitan Waste Control Commission (MWCC) in St. Paul, Minn., and Rosemount Analytical Division in La Habre, Calif., entered into a joint agreement with EPA to demonstrate a hot' THC monitoring system to detect THCs in stack gases. The objectives of the study are to determine the feasibility of THC monitoring of sludge incinerator emissions; evaluate the long term reliability, cost of operation, and consistency of a continuous THC monitoring system in an incinerator environment; and determine the correlation of THC stack concentration to incinerator and scrubber operating conditions, carbon monoxide concentration, and specific VOC emissions.
Pollution prevention through total quality
Stoltz, D.L.; Byrant, M.G.; Eggers, D.M.; Gough, R.W.; Schlosberg, W.H.
Application of Total Quality to AlliedSignal Inc., Kansas City Division`s (KCD) Pollution Prevention Program has created a dynamic and focused effort to significantly reduce process inefficiencies and waste generation. KCD is demonstrating TQ`s usefulness by empowering associates and obtaining their buy-in and ownership of pollution prevention principles. Specific pollution prevention working groups include: establishing a comprehensive recycling process; (2) capitalizing on Environmentally Conscious Manufacturing (ECM) expertise; and (3) encouraging the internal implementation of ECM. TQ produces the performance results that promote and sustain plant-wide pollution prevention goals and activities. KCD uses AlliedSignall`s nine step ``Process Improvement Problem/Solving Model`` (Appendix A). Although this program only formally began within the past year, many of the tools have been used over the last eight years to achieve pollution prevention objectives. This paper focuses on the new attitude and gives examples of how each of the nine steps is being used in the KCD Pollution Prevention Program. This paper describe s each step of the process and provides specific pollution prevention examples.
A new method of missile in-flight alignment under large heading error
Yandong Wang; Junliang Cai; Xiaoqiang Chen; Zhihua Han; Qingchang Ji
Aiming at large initial heading error at missile flight, a new in-flight alignment method is introduced, in which a H?? filter and a Kalman filter are synthesized. When there is large initial heading error, the H?? filter is used, at the same time, the observability of each state variable is calculated. When the observability of attitude angle error reaches a
Modular taper junction corrosion and failure: how to approach a recalled total hip arthroplasty implant.
Pivec, Robert; Meneghini, R Michael; Hozack, William J; Westrich, Geoffrey H; Mont, Michael A
Corrosion at the modular neck-stem taper junction has become an increasingly important topic as several reports have identified this couple as a possible source for early failure with findings similar to failed metal-on-metal hip arthroplasties. Recently, two different modular stem systems from a single manufacturer were voluntarily recalled due to concerns of failure of the modular taper junction. We discuss how to approach the diagnosis and management of patients with these particular stem systems. We further reviewed the literature to evaluate whether this is a manufacturer-specific defect or indicative of a broader trend. Recent studies appear to implicate the basic design of the neck-stem taper junction, rather than a single manufacturer, which is at high risk for fretting and corrosion. PMID:24090661
Total quality management: the second industrial revolution
Gopal K. Kanji
This article describes the concept and basic approach to total quality management. Quality is examined and explained in the context of continuous customer's satisfaction and total quality management by involving everyone's commitment to achieving quality at a low cost. Different stages of total quality management in practice are suggested and various techniques to implement these are also discussed. It has
8, 31433162, 2008 Total ozone over
Paris-Sud XI, Universitķ de
Chemistry and Physics Discussions Total column ozone variations over oceanic region around Indian sub. There is a well defined diurnal (daytime) variation in total column ozone with maximum content around the noon% of the global ozone is located in the tropics between 25 N and 25 S, and a strong decadal variation of total
Total solar eclipse of 3 November 1994
NASA Technical Reports Server (NTRS)
Espenak, Fred; Anderson, Jay
A total eclipse of the Sun will be visible from the southern half of the Western Hemisphere on 3 November 1994. The path of the Moon's shadow passes through Peru, Chile, Bolivia, Paraguay, and Brazil. Detailed predictions for this event are presented and include tables of geographic coordinates of the path of totality, local circumstances for hundreds of cities, maps of the path of total and partial eclipse, weather prospects, and the lunar limb profile.
Total quality management in American industry.
Widtfeldt, A K; Widtfeldt, J R
The definition of total quality management is conformance to customer requirements and specifications, fitness for use, buyer satisfaction, and value at an affordable price. The three individuals who have developed the total quality management concepts in the United States are W.E. Deming, J.M. Juran, and Philip Crosby. The universal principles of total quality management are (a) a customer focus, (b) management commitment, (c) training, (d) process capability and control, and (e) measurement through quality improvement tools. Results from the National Demonstration Project on Quality Improvement in Health Care showed the principles of total quality management could be applied to healthcare. PMID:1616505
25The Last Total Solar Eclipse...Ever! Total solar eclipses happen
25The Last Total Solar Eclipse...Ever! Total solar eclipses happen because the angular size a total solar eclipse. When will that happen? Image courtesy Fred Espenak http://sunearth.gsfc.nasa.gov/eclipse/eclipse the distance from your answer to Problem 4? Problem 7 - When will the last Total Solar Eclipse be sighted
Early clinical failure of the Birmingham metal-on-metal hip resurfacing is associated with metallosis and soft-tissue necrosis.
Ollivere, B; Darrah, C; Barker, T; Nolan, J; Porteous, M J
The rate and mode of early failure in 463 Birmingham hip resurfacings in a two-centre, multisurgeon series were examined. Of the 463 patients two have died and three were lost to follow-up. The mean radiological and clinical follow-up was for 43 months (6 to 90). We have revised 13 resurfacings (2.8%) including seven for pain, three for fracture, two for dislocation and another for sepsis. Of these, nine had macroscopic and histological evidence of metallosis. The survival at five years was 95.8% (95% confidence interval (CI) 94.1 to 96.8) for revision for all causes and 96.9% (95% CI 95.5 to 98.3) for metallosis. The rate of metallosis related revision was 3.1% at five years. Risk factors for metallosis were female gender, a small femoral component, a high abduction angle and obesity. We do not advocate the use of the Birmingham Hip resurfacing procedure in patients with these risk factors. PMID:19651828
The effect of 'running-in' on the tribology and surface morphology of metal-on-metal Birmingham hip resurfacing device in simulator studies.
Vassiliou, K; Elfick, A P D; Scholes, S C; Unsworth, A
It is well documented that hard bearing combinations show a running-in phenomenon in vitro and there is also some evidence of this from retrieval studies. In order to investigate this phenomenon, five Birmingham hip resurfacing devices were tested in a hip wear simulator. One of these (joint 1) was also tested in a friction simulator before, during, and after the wear test and surface analysis was conducted throughout portions of the testing. The wear showed the classical running in with the wear rate falling from 1.84 mm3 per 10(6) cycles for the first 10(6) cycles of testing to 0.24 mm3 per 10(6) cycles over the final 2 x 10(6) cycles of testing. The friction tests suggested boundary lubrication initially, but at 1 x 10(6) cycles a mixed lubrication regime was evident. By 2 x 10(6) cycles the classical Stribeck curve had formed, indicating a considerable contribution from the fluid film at higher viscosities. This continued to be evident at both 3 x 10(6) and 5 x 10(6) cycles. The surface study complements these findings. PMID:16669393
Quality costs and total quality management
Jens J. Dahlgaard; Kai Kristensen; Gopal K. Kanji
The quality cost in total quality management is one of the most important aspects of the development of a quality management system. In this article a model of a quality management system has been developed incorporating the quality cost of the organization. Finally to evaluate the quality management system of some printing industries a new indirect method of measuring total
A total quality management methodology for universities
Jose Carlos Flores-Molina
This research document is motivated by the need for a systemic, efficient quality improvement methodology at universities. There exists no methodology designed for a total quality management (TQM) program in a university. The main objective of this study is to develop a TQM Methodology that enables a university to efficiently develop an integral total quality improvement (TQM) Plan. ^ Current
Hotel name Date #of days TOTAL Destination*
Duchowski, Andrew T.
Hotel name Date #of days TOTAL TOTAL: Name*: Destination*: Acct to charge*: Date submitted*: Return AMOUNT Car rental Parking Taxi, limo, shuttle Business phone calls Internet for business use Gas Tips/limo/shuttle, tips, tolls, and portage. Original signatures are required. Purpose of trip*: Comments of Special
The polaron at large total momentum
H. Spohn
Proves that for dimensions d=1, 2 the polaron (with general dispersion relation and couplings) has a unique ground state for any value of the total momentum (particle+Bose field). For d>or=3 and for sufficiently small total momentum the author shows the existence of a unique ground state, extending however the domain of uniqueness known previously.
The rationale and supporting experimental data for revising EPA's 1996 "Guidance for Total Organics" are summarized in this document. It reports the results of reseach and investigation of improvements to the Total Organic Emissions (TOE) guidance used by EPA to measure recovera...
Optimistic Total Order in Wide Area Networks
Ant¾nio LuĒs Pinto Ferreira De Sousa; Jose Pereira; Francisco Moura; Rui Carlos Oliveira
Total order multicast greatly simplifies the implementa- tion of fault-tolerant services using the replicated state ma- chine approach. The additional latency of total ordering can be masked by taking advantage of spontaneous order- ing observed in LANs: A tentative delivery allows the ap- plication to proceed in parallel with the ordering protocol. The effectiveness of the technique rests on the
TOTAL ECLIPSE EXPEDITION AUSTRALIA NOVEMBER 2012 November 14th next year, will see the most accessible Total Solar Eclipse until August 2017. We at Ulster travel are hoping that you will not want of Cairns. This eclipse being one of the few that crosses an international airport, will be extremely
Total Internal Reflection Ellipsometry: Principles and Applications
Hans Arwin; Michal Poksinski; Knut Johansen
A concept for a measurement technique based on ellipsometry in conditions of total internal reflection is presented. When combined with surface plasmon resonance (SPR) effects, this technique becomes powerful for monitoring and analyzing adsorption and desorption on thin semitransparent metal films as well as for analyzing the semitransparent films themselves. We call this technique total internal reflection ellipsometry (TIRE). The
Weather biases in the NFL totals market
Richard Borghesi
I examine outcome predictability in the National Football League totals betting market using data from the 1984 through 2004 seasons. Results suggest that while weather is an important determinant of scoring, the market does not accurately incorporate the effects of adverse conditions into totals bet prices. Specifically, I demonstrate that heat, wind and rain reduce point production, and provide evidence
Educating Deaf Children: The Total Approach.
ERIC Educational Resources Information Center
Santa Ana Unified School District, CA.
The use of total communication in educating deaf preschool and elementary school students in the Santa Ana Program for the Hearing Impaired, Orange County, California, is described. Total communication is explained to consist of auditory training, speech, speechreading, fingerspelling, and the language of signs. Aspects of the program describedģ
Approximating total flow time on parallel machines
Stefano Leonardi; Danny Raz
We consider the problem of optimizing the total flow timeof a stream of jobs that are released over time in a multiprocessorsetting. This problem is NP-hard even when weallow preemption, and have only two machines. Althoughthe total (or average) flow time is widely accepted as a goodmeasurement of the overall quality of service, no approximationalgorithms were known for this basic
Total parenteral nutrition-related gastroenterological complications.
Guglielmi, F W; Boggio-Bertinet, D; Federico, A; Forte, G B; Guglielmi, A; Loguercio, C; Mazzuoli, S; Merli, M; Palmo, A; Panella, C; Pironi, L; Francavilla, A
Total parenteral nutrition is a life saving therapy for patients with chronic gastrointestinal failure, being an effective method for supplying energy and nutrients when oral or enteral feeding is impossible or contraindicated. Clinical epidemiological data indicate that total parenteral nutrition may be associated with a variety of problems. Herein we reviewed data on the gastroenterological tract regarding: (i) total parenteral nutrition-related hepatobiliary complications; and (ii) total parenteral nutrition-related intestinal complications. In the first group, complications may vary from mildly elevated liver enzyme values to steatosis, steatohepatitis, cholestasis, fibrosis and cirrhosis. In particular, total parenteral nutrition is considered to be an absolute risk factor for the development of biliary sludge and gallstones and is often associated with hepatic steatosis and intrahepatic cholestasis. In general, the incidence of total parenteral nutrition-related hepatobiliary complications has been reported to be very high, ranging from 20 to 75% in adults. All these hepatobiliary complications are more likely to occur after long-term total parenteral nutrition, but they seem to be less frequent, and/or less severe in patients who are also receiving oral feeding. In addition, end-stage liver disease has been described in approximately 15-20% of patients receiving prolonged total parenteral nutrition. Total parenteral nutrition-related intestinal complications have not yet been adequately defined and described. Epidemiological studies intended to define the incidence of these complications, are still ongoing. Recent papers confirm that in both animals and humans, total parenteral nutrition-related intestinal complications are induced by the lack of enteral stimulation and are characterised by changes in the structure and function of the gut. Preventive suggestions and therapies for both these gastroenterological complications are reviewed and reported in the present review. PMID:16766237
Total body calcium analysis. [neutron irradiation
NASA Technical Reports Server (NTRS)
Lewellen, T. K.; Nelp, W. B.
A technique to quantitate total body calcium in humans is developed. Total body neutron irradiation is utilized to produce argon 37. The radio argon, which diffuses into the blood stream and is excreted through the lungs, is recovered from the exhaled breath and counted inside a proportional detector. Emphasis is placed on: (1) measurement of the rate of excretion of radio argon following total body neutron irradiation; (2) the development of the radio argon collection, purification, and counting systems; and (3) development of a patient irradiation facility using a 14 MeV neutron generator. Results and applications are discussed in detail.
Technicon's block digestor method for the simultaneous determination of total phosphorus and total Kjeldahl nitrogen has been evaluated and modified for the semi-automated determination of these constituents in surface water and domestic and industrial wastes. The Technicon diges...
Total Building Air Management: When Dehumidification CountsĀ
Chilton, R. L.; White, C. L.
, total air management of sensible and latent heat, filtration and zone pressure was brought about through the implementation of non-integrated, composite systems. Composite systems typically are built up of multi-vendor equipment each of which perform...
Need total sulfur content? Use chemiluminescence
Kubala, S.W.; Campbell, D.N. [Fluid Data, Inc., Angleton, TX (United States); DiSanzo, F.P. [Mobil Technology Co., Paulsboro, NJ (United States)
Regulations issued by the United States Environmental Protection Agency require petroleum refineries to reduce or control the amount of total sulfur present in their refined products. These legislative requirements have led many refineries to search for online instrumentation that can produce accurate and repeatable total sulfur measurements within allowed levels. Several analytical methods currently exist to measure total sulfur content. They include X-ray fluorescence (XRF), microcoulometry, lead acetate tape, and pyrofluorescence techniques. Sulfur-specific chemiluminescence detection (SSCD) has recently received much attention due to its linearity, selectivity, sensitivity, and equimolar response. However, its use has been largely confined to the area of gas chromatography. This article focuses on the special design considerations and analytical utility of an SSCD system developed to determine total sulfur content in gasoline. The system exhibits excellent linearity and selectivity, the ability to detect low minimum levels, and an equimolar response to various sulfur compounds. 2 figs., 2 tabs.
Total Petroleum Hydrocarbons (TPH): ToxFAQs
Total lymphoid irradiation in alloimmunity and autoimmunity
Strober, S.
Total lymphoid irradiation has been used as an immunosuppressive regimen in autoimmune disease and organ transplantation. The rationale for its use originated from studies of patients with Hodgkin disease, in whom this radiotherapy regimen was noted to induce profound and long-lasting immune suppression and yet was well tolerated, with few long-term side effects. Total lymphoid irradiation is a unique immunosuppressive regimen that produces a selective (and long-lasting) reduction in the number and function of helper T cells and certain subsets of B cells. Conventional immunosuppressive drugs show little selectivity, and their effects are short-lived. The most important aspect of total lymphoid irradiation is the potential for achieving transplantation tolerance and permanent remissions in autoimmune disease in laboratory animals. Attempts are being made to achieve similar goals in humans given total lymphoid irradiation, so that immunosuppressive drugs can be ultimately withdrawn from transplant recipients and patients with lupus nephritis. 28 references.
Total Solar Eclipse--A Caribbean Adventure.
ERIC Educational Resources Information Center
Green, Steven; Tunstall, Louisa; Tunstall, Neil
Describes the experiences of two high school students who traveled to the Caribbean island of Curacao to view a total solar eclipse and prepare methods for teaching classmates about the eclipse the following school year. (Author/WRM)
Practical considerations for permanent total enclosures
Worrall, M. [Amcec Adsorption Systems, Schaumburg, IL (United States)
This paper considers some of the practical consideration of Permanent Total Enclosures (PTEs) for gravure printing facilities. In particular the dispersion of fugitive losses from the presses by thermal air currents generated by heat from the press dryers.
Recent residential monitoring studies have demonstrated that significant portion of total exposure of infants and children to environmental contaminants can result from contamination of food in the home. Children's foods become contaminated through handling and contact with surf...
Atraumatic floating clavicle and total claviculectomy.
Attarian, D E
We describe a patient with a floating clavicle of atraumatic origin treated by total claviculectomy. Clavicular function and anatomy are summarized relative to complete excision. Other treatment options for panclavicular instability are also discussed. PMID:12132804
Total synthesis and study of myrmicarin alkaloids
Ondrus, Alison Evelynn, 1981-
I. Enantioselective Total Synthesis of Tricyclic Myrmicarin Alkaloids An enantioselective gram-scale synthesis of a key dihydroindolizine intermediate for the preparation of myrmicarin alkaloids is described. Key transformations ...
Mini-incision for total hip arthroplasty
John M Wright; Heber C Crockett; Sam Delgado; Stephen Lyman; Mike Madsen; Thomas P Sculco
A group of 42 primary total hip arthroplasties performed through an abridged surgical incision (group 1) was prospectively compared to a cohort of 42 primary total hip arthroplasties performed through a standard surgical incision (group 2). The length of the incision was 8.8 ▒ 1.5 cm for group 1 and 23.0 ▒ 2.1 cm for group 2. The groups were
A Total Quality Management Methodology for Universities
Jose C Flores-Molina
This research document is motivated by the need for a systemic, efficient quality improvement methodology at universities. There exists no methodology designed for a total quality management (TQM) program in a university. The main objective of this study is to develop a TQM Methodology that enables a university to efficiently develop an integral total quality improvement (TQM) Plan.\\u000aCurrent research
Total antioxidant capacity of the Korean diet
Han, Jeong-Hwa; Lee, Hye-Jin; Cho, Mi Ran; Chang, Namsoo; Kim, Yuri; Oh, Se-Young
BACKGROUND/OBJECTIVES The objective of this study was to measure and/or estimate the total antioxidant capacity of the Korean diet. MATERIALS/METHODS Eighty-one plant foods that were expected to exhibit rather high antioxidant activities were selected from the Korean diet using the Fifth Korean National Health and Nutrition Survey (KNHANES V). These foods were categorized into 11 food groups: cereals, potatoes, legumes, nuts, vegetables, kimchies, mushrooms, fruits, fruit juices, sea weeds, and oils. The foods were mixed in the proportions specified in traditional Korean recipes and analyzed. The measured indicators for antioxidant capacities were total phenolics, 2,2-diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), and Trolox equivalent antioxidant capacity (TEAC). RESULTS Total phenolics were high in the fruit juices, nuts, vegetables, and fruits; and the average DPPH, ORAC, and TEAC values were high in the vegetables, fruits, fruit juices, and nuts. The correlation coefficient between the content of total phenolics of each food and the in vitro antioxidant capacity was relatively high at 0.851. The intake of total phenolics per capita per day in the Republic of Korea was estimated to be 127 mg. The total dietary antioxidant capacity (TDAC) values, which were obtained from the total antioxidant capacity of each food, taking into account the intake of each food, were 20,763, 54,335, and 876.4 Ąmol of Trolox equivalents using the DPPH, ORAC, and TEAC methods, respectively. The food group that contributed the most to the Korean TDAC was cereals at 39.7%, followed by fruits and vegetables at 27.8% and 13.9%, respectively. The contribution of legumes, nuts, fruit juices, and mushrooms was quite minimal at less than 2% each. CONCLUSIONS The content of total phenolics and the antioxidant capacity of the Korean diet are significantly correlated and the high contributing food groups are cereals, fruits, and vegetables. PMID:24741403
The Total Irradiance Monitor (TIM): Instrument Design
Greg Kopp; George Lawrence
The Total Irradiance Monitor (TIM) instrument is designed to measure total solar irradiance with an absolute accuracy of 100\\u000a parts per million. Four electrical substitution radiometers behind precision apertures measure input radiant power while providing\\u000a redundancy. Duty cycling the use of the radiometers tracks degradation of the nickel-phosphorous absorptive black radiometer\\u000a interiors caused by solar exposure. Phase sensitive detection at
The Total Irradiance Monitor (TIM): Instrument Design
Greg Kopp; George Lawrence
The Total Irradiance Monitor (TIM) instrument is designed to measure total solar irradiance with an absolute accuracy of 100\\u000a parts per million. Four electrical substitution radiometers behind precision apertures measure input radiant power while providing\\u000a redundancy. Duty cycling the use of the radiometers tracks degradation of the nickel-phosphorous absorptive black radiometer\\u000a interiors caused by solar exposure. Phase sensitive detection at
Total acquired vulval synechia: an unusual presentation.
Kallam, Anji Reddy
An unusual case of Acquired Total vulval synechia due to vulvar Lichen planus is reported in an 18-year-old girl, which is an extremely rare condition. It has a potential for producing extensive scarring and narrowing of introitus resulting in dyspareunia and rarely carcinoma of vulva. Successful surgical management of total vulvar synechiae in patient suffering from Lichen Planus is being reported. PMID:26023590
Total Acquired Vulval Synechia: An Unusual Presentation
An unusual case of Acquired Total vulval synechia due to vulvar Lichen planus is reported in an 18-year-old girl, which is an extremely rare condition. It has a potential for producing extensive scarring and narrowing of introitus resulting in dyspareunia and rarely carcinoma of vulva. Successful surgical management of total vulvar synechiae in patient suffering from Lichen Planus is being reported. PMID:26023590
Asymmetric, stereocontrolled total synthesis of paraherquamide A.
Williams, Robert M; Cao, Jianhua; Tsujishima, Hidekazu; Cox, Rhona J
The first total synthesis of paraherquamide A, a potent anthelmintic agent isolated from various Penicillium sp. with promising activity against drug-resistant intestinal parasites, is reported. Key steps in this asymmetric, stereocontrolled total synthesis include a new enantioselective synthesis of alpha-alkylated-beta-hydroxyproline derivatives to access the substituted proline nucleus and a highly diastereoselective intramolecular S(N)2' cyclization to generate the core bicyclo[2.2.2]diazaoctane ring system. PMID:14519003
Effects of xenobiotics on total antioxidant capacity
The objective of this article was to review the effects of xenobiotics on total antioxidant capacity (TAC). Measurement of TAC is appropriate for evaluation of the total antioxidant defenses of blood, cells, and different kinds of tissues and organs. TAC is reduced by alcoholism, smoking, and exposure to radiation, herbicides, carbon monoxide, carbon tetrachloride, lead, arsenic, mercury, cadmium, aluminum, and other toxic elements. The test is also an important tool in evaluating environmental and occupational exposure. PMID:23554550
Total energies of improved quasicrystal models
Phillips, R.; Deng, H.; Carlsson, A.E.; Daw, M.S. (Sandia National Laboratories, Livermore, California 94550 and Washington University, St. Louis, Missouri (USA))
The first electronic total-energy calculations are performed on a 6D-3D projection model for the TiMn quasicrystal, as well as two refined models obtained by filling vacant spaces. The total energies correlate almost perfectly with the reduction of the vacant space, and suggest that future modeling efforts should concentrate on increasing the coordination number of Ti sites in the glue'' regions between the large icosahedral clusters which form the backbone of the structure.
k-tuple total domination in graphs
Michael A. Henning; Adel P. Kazemi
A set S of vertices in a graph G is a k-tuple total dominating set, abbreviated kTDS, of G if every vertex of G is adjacent to least k vertices in S. The minimum cardinality of a kTDS of G is the k-tuple total domination number of G. For a graph to have a kTDS, its minimum degree is at
Rising Total Hadron-Hadron Cross Sections
Giorgio Giacomelli
A historical summary is made on the measurements concerning the rising total hadron-hadron cross sections at high energies. The first part of this paper concerns the total cross section measurements performed at the Brookhaven, Serpukhov and Fermilab fixed target accelerators; then the measurements at the CERN Intersecting Storage Rings (ISR), and at the CERN and at the Tevatron Fermilab proton-antiproton colliders; finally the cosmic ray measurements at even higher energies. A short discussion on Conclusions and Perspectives follows.
Autonoma de Madrid, Universidad
Total Antioxidant, Phenolic Compounds, and Total Oxidant Status of Certified and Uncertified Turkey's Honeys
Emine Nur Herken; Ozcan Erel; Salih Guzel; Hakim Celik; Senol Ibanoglu
In this study, total oxidant status (TOS), total antioxidant capacity (TAC) and total phenols (TP) of seventeen certified and eight uncertified honey samples were analyzed. The TAC and TOS of the samples were determined using novel methods. Uncertified honey samples had significantly lower values for their TP, TAC and TOS contents than those of certified honey samples. There was significant
Exploring the common ground of total relationship management (TRM) and total quality management (TQM)
Mosad Zineldin
This paper is a continuation of our research effort to develop a new approach to total relationship management. It is a theoretical and conceptual one, providing marketing and management ideas on how to integrate total quality management (TQM) and total relationship management (TRM) in order to achieve better quality relationships, product\\/service and process. Aims to shed light on how TRM
Predicting the Total Charm Cross Section
Vogt, R
We discuss the energy dependence of the total charm cross section and some of its theoretical uncertainties including the quark mass, scale choice and the parton densities. Extracting the total charm cross section from data is a non-trivial task. To go from a finite number of measured D mesons in a particular decay channel to the total c{bar c} cross section one must: divide by the branching ratio for that channel; correct for the luminosity, {sigma}{sub D} = N{sub D}/Lt; extrapolate to full phase space from the finite detector acceptance; divide by two to get the pair cross section from the single Ds; and multiply by a correction factor to account for unmeasured charm hadrons. Early fixed-target data were at rather low p{sub T}, making the charm quark mass the most relevant scale. At proton and ion colliders, although the RHIC experiments can access the full pT range and thus the total cross section, the data reach rather high p{sub T}, p{sub T} >> m, making p{sub T} (m{sub T}) the most relevant scale. Here we focus on the total cross section calculation where the quark mass is the only relevant scale.
Determining HPGe Total Detection Efficiency Using ?¢? Coincidence
Erikson, Luke E.; Keillor, Martin E.; Aalseth, Craig E.; Hossbach, Todd W.; Mizouni, Leila K.; Stavenger, Timothy J.; McDonald, Benjamin S.; Lepel, Elwood A.; Greenwood, Lawrence R.; Rutherford, Crystal E.
Abstract Both the peak and total detection efficiencies are generally needed in order to calculate sample activity from a gamma spectroscopic measurement, except in the case of isotope specific calibration. This is particularly true when the sample is in close proximity to the detector and corrections for cascade summing effects are required to avoid significant inaccuracy in the result. These corrections use the total detection efficiency to correct for summing-in and summing-out events, and the extent of the correction depends on both the geometry and the gamma cascade for the isotope in question. Experimentally determining the total efficiency is a labor intensive endeavor requiring multiple measurements with a set of single-gamma-emitting standards. Modeling the total efficiency vs. energy may be less time consuming, but is also likely to produce less confidence in the final result. Pacific Northwest National Laboratory's Radiation Detection and Nuclear Sciences group has constructed a low background 14-crystal HPGe array for sample measurement; in all measurements, samples will be in close proximity to the germanium crystals. This close geometry and the sheer number efficiency calibrations required for the system have led us to investigate methods to simplify the efficiency calibration procedure. One method we are developing uses the Y-Y coincidence plane to isolate Compton scattering event populations, allowing experimental determination of total detection efficiency values from the measurement of a single mixed isotope standard. A description of the analysis and experimental results of this method are presented.
Total and inorganic arsenic in Antarctic macroalgae.
FarĒas, Silvia; Smichowski, Patricia; Vķlez, Dinoraz; Montoro, Rosa; Curtosi, Antonio; VodopĒvez, Cristian
The Antarctic region offers unparalleled possibilities of investigating the natural distribution of metals and metalloids, such as arsenic. Total and inorganic As were analysed in nine species of Antarctic macroalgae collected during the 2002 summer season in the Potter Cove area at Jubany-Dallmann Station (South Shetland Islands, Argentinian Base). Total As was determined by inductively coupled plasma-optical emission spectrometry after microwave-assisted acid digestion. Inorganic As was determined by acid digestion, solvent extraction, flow injection-hydride generation-atomic absorption spectrometry. Total As ranged from 5.8 microg g(-1) dry weight (dw) (Myriogramme sp.) to 152 microg g(-1)dw (Himantothallus grandifolius). Total As concentrations were higher in Phaeophytes (mean+/-SD: 71+/-44 microg g(-1)dw) than in Rhodophytes (mean+/-SD: 15+/-11 microg g(-1)dw). Inorganic As ranged from 0.12 microg g(-1) (Myriogramme sp.) to 0.84 microg g(-1)dw (Phaeurus antarcticus). The percentage of inorganic As with respect to total As was 0.7 for Phaeophytes, but almost 4 times higher for Rhodophytes (2.6). The work discusses possible causes for the presence of As in marine organisms in that pristine environment. PMID:17544055
A high performance totally ordered multicast protocol
NASA Technical Reports Server (NTRS)
Montgomery, Todd; Whetten, Brian; Kaplan, Simon
This paper presents the Reliable Multicast Protocol (RMP). RMP provides a totally ordered, reliable, atomic multicast service on top of an unreliable multicast datagram service such as IP Multicasting. RMP is fully and symmetrically distributed so that no site bears un undue portion of the communication load. RMP provides a wide range of guarantees, from unreliable delivery to totally ordered delivery, to K-resilient, majority resilient, and totally resilient atomic delivery. These QoS guarantees are selectable on a per packet basis. RMP provides many communication options, including virtual synchrony, a publisher/subscriber model of message delivery, an implicit naming service, mutually exclusive handlers for messages, and mutually exclusive locks. It has commonly been held that a large performance penalty must be paid in order to implement total ordering -- RMP discounts this. On SparcStation 10's on a 1250 KB/sec Ethernet, RMP provides totally ordered packet delivery to one destination at 842 KB/sec throughput and with 3.1 ms packet latency. The performance stays roughly constant independent of the number of destinations. For two or more destinations on a LAN, RMP provides higher throughput than any protocol that does not use multicast or broadcast.
Assay development status report for total cyanide
Simpson, B.C. [Westinghouse Hanford Co., Richland, WA (United States); Jones, T.E.; Pool, K.H. [Pacific Northwest Lab., Richland, WA (United States)
A validated cyanide assay that is applicable to a variety of tank waste matrices is necessary to resolve certain waste tank safety issues and for purposes of overall waste characterization. The target for this effort is an assay with an applicable range of greater than 1,000 ppM (0.10 wt%) total cyanide and a confidence level greater than 80%. Figure 1 illustrates the operating regime of the proposed cyanide assay method. The Assay Development Status Report for Total Cyanide will summarize the past experience with cyanide analyses on-tank waste matrices and will rate the status of the analytical methods used to assay total cyanide (CN{sup {minus}} ion) in the tank waste matrices as acceptable or unacceptable. This paper will also briefly describe the current efforts for improving analytical resolution of the assays and the attempts at speciation.
Total Solar Eclipse of 2002 December 04
NASA Technical Reports Server (NTRS)
Espenak, Fred; Anderson, Jay
On 2002 December 04, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Southern Hemisphere. The path of the Moon's umbral shadow begins in the South Atlantic, crosses southern Africa and the Indian Ocean, and ends at sunset in southern Australia. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes the southern two thirds of Africa, Antarctica, Indian Ocean and Australia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 400 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.
Total Solar Eclipse of 2001 June 21
NASA Technical Reports Server (NTRS)
Espenak, Fred; Anderson, Jay
On 2001 June 21, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Southern Hemisphere. The path of the Moon's umbral shadow begins in the South Atlantic, crosses southern Africa and Madagascar, and ends at sunset in the Indian Ocean. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes eastern South America and the southern two thirds of Africa. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 350 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.
Outcome of total claviculectomy in six cases.
Wessel, Ronald N; Schaap, Gerard R
Total claviculectomy is a rare surgical procedure that has been performed for more than 90 years for a variety of indications, such as malignancy, trauma, and infection. What are the results for the pain score, and what is the influence of a total claviculectomy on the range of motion of the shoulder? We could not find the answers in the literature and analyzed 6 cases of total claviculectomy. The pain scores are good in a chronic osteitis case and in the two malignancy cases. In the 3 posttraumatic cases, the indication was pain, and all 3 had poor results because of persistent pain. All 6 patients had full range of motion. A resection of the entire clavicle did not disturb the motion of the shoulder. A tendency but no final conclusions can be drawn because of too few patients and heterogeneous indications. PMID:17188905
Total internal reflection ellipsometry: principles and applications.
Arwin, Hans; Poksinski, Michal; Johansen, Knut
A concept for a measurement technique based on ellipsometry in conditions of total internal reflection is presented. When combined with surface plasmon resonance (SPR) effects, this technique becomes powerful for monitoring and analyzing adsorption and desorption on thin semitransparent metal films as well as for analyzing the semitransparent films themselves. We call this technique total internal reflection ellipsometry (TIRE). The theory of ellipsometry under total internal reflection combined with SPR is discussed for some simple cases. For more advanced cases and to prove the concept, simulations are performed with the Fresnel formalism. The use of TIRE is exemplified by applications in protein adsorption, corrosion monitoring, and adsorption from opaque liquids on metal surfaces. Simulations and experiments show greatly enhanced thin-film sensitivity compared with ordinary ellipsometry. PMID:15176189
Failure of aseptic revision total knee arthroplasties
Leta, Tesfaye H; Lygre, Stein HÕkon L; Skredderstuen, Arne; Hallan, Geir; Furnes, Ove
Background and purpose In Norway, the proportion of revision knee arthroplasties increased from 6.9% in 1994 to 8.5% in 2011. However, there is limited information on the epidemiology and causes of subsequent failure of revision knee arthroplasty. We therefore studied survival rate and determined the modes of failure of aseptic revision total knee arthroplasties. Method This study was based on 1,016 aseptic revision total knee arthroplasties reported to the Norwegian Arthroplasty Register between 1994 and 2011. Revisions done for infections were not included. Kaplan-Meier and Cox regression analyses were used to assess the survival rate and the relative risk of re-revision with all causes of re-revision as endpoint. Results 145 knees failed after revision total knee arthroplasty. Deep infection was the most frequent cause of re-revision (28%), followed by instability (26%), loose tibial component (17%), and pain (10%). The cumulative survival rate for revision total knee arthroplasties was 85% at 5 years, 78% at 10 years, and 71% at 15 years. Revision total knee arthroplasties with exchange of the femoral or tibial component exclusively had a higher risk of re-revision (RR = 1.7) than those with exchange of the whole prosthesis. The risk of re-revision was higher for men (RR = 2.0) and for patients aged less than 60 years (RR = 1.6). Interpretation In terms of implant survival, revision of the whole implant was better than revision of 1 component only. Young age and male sex were risk factors for re-revision. Deep infection was the most frequent cause of failure of revision of aseptic total knee arthroplasties. PMID:25267502
An Operational Perspective of Total Lightning Information
NASA Technical Reports Server (NTRS)
Nadler, David J.; Darden, Christopher B.; Stano, Geoffrey; Buechler, Dennis E.
The close and productive collaborations between the NWS Warning and Forecast Office, the Short Term Prediction and Research Transition Center at NASA Marshall Space Flight Center and the University of Alabama in Huntsville have provided a unique opportunity for science sharing and technology transfer. One significant technology transfer that has provided immediate benefits to NWS forecast and warning operations is the use of data from the North Alabama Lightning Mapping Array. This network consists of ten VHF receivers deployed across northern Alabama and a base station located at the National Space Science and Technology Center. Preliminary investigations done at WFO Huntsville, along with other similar total lightning networks across the country, have shown distinct correlations between the time rate-of-change of total lightning and trends in intensity/severity of the parent convective cell. Since May 2003 when WFO HUN began receiving these data - in conjunction with other more traditional remotely sensed data (radar, satellite, and surface observations) -- have improved the situational awareness of the WFO staff. The use of total lightning information, either from current ground based systems or future space borne instrumentation, may substantially contribute to the NWS mission, by enhancing severe weather warning and decision-making processes. Operational use of the data has been maximized at WFO Huntsville through a process that includes forecaster training, product implementation, and post event analysis and assessments. Since receiving these data, over 50 surveys have been completed highlighting the use of total lightning information during significant events across the Tennessee Valley. In addition, around 150 specific cases of interest have been archived for collaborative post storm analysis. From these datasets, detailed trending information from radar and total lightning can be compared to corresponding damage reports. This presentation will emphasize the effective use of total lightning information in warning decision making along with best practices for implementation of new technologies into operations.
Secondary Hemorrhage After Total Laparoscopic Hysterectomy
Prathap, Talwar; Kaur, Harneet; Shabnam, Khan; Kandhari, Dimple; Chopade, Gaurav
Background and Objectives: The purpose of this study is to estimate the cumulative incidence, patient characteristics, and potential risk factors for secondary hemorrhage after total laparoscopic hysterectomy. Methods: All women who underwent total laparoscopic hysterectomy at Paul's Hospital between January 2004 and April 2012 were included in the study. Patients who had bleeding per vaginam between 24 hours and 6 weeks after primary surgery were included in the analysis. Results: A total of 1613 patients underwent total laparoscopic hysterectomy during the study period, and 21 patients had secondary hemorrhage after hysterectomy. The overall cumulative incidence of secondary hemorrhage after total laparoscopic hysterectomy was 1.3%. The mean size of the uterus was 541.4 g in the secondary hemorrhage group and 318.9 g in patients without hemorrhage, which was statistically significant. The median time interval between hysterectomy and secondary hemorrhage was 13 days. Packing was sufficient to control the bleeding in 13 patients, and 6 patients required vault suturing. Laparoscopic coagulation of the uterine artery was performed in 1 patient. Uterine artery embolization was performed twice in 1 patient to control the bleeding. Conclusions: Our data suggest that secondary hemorrhage is rare but may occur more often after total laparoscopic hysterectomy than after other hysterectomy approaches. Whether it is related to the application of thermal energy to tissues, which causes more tissue necrosis and devascularization than sharp culdotomy in abdominal and vaginal hysterectomies, is not clear. A large uterus size, excessive use of an energy source for the uterine artery, and culdotomy may play a role. PMID:25392609
Gemella haemolysans Infection in Total Hip Arthroplasty
Rose, Barry; Jeer, Parminder J. S.; Spriggins, Anthony J.
Gemella haemolysans is a Gram-positive coccus and commensal of the upper respiratory tract and oral mucosa that rarely causes clinically important infections. There is only one previous report of this organism causing periprosthetic infection, in a total knee arthroplasty. We present a case of septic loosening of an uncemented total hip arthroplasty due to G. haemolysans, in an asplenic patient with insulin dependent diabetes mellitus. Treatment with two-stage revision has been successful at 7 years of follow-up. PMID:23227390
The Total Irradiance Monitor (TIM): Instrument Design
NASA Astrophysics Data System (ADS)
Kopp, Greg; Lawrence, George
The Total Irradiance Monitor (TIM) instrument is designed to measure total solar irradiance with an absolute accuracy of 100 parts per million. Four electrical substitution radiometers behind precision apertures measure input radiant power while providing redundancy. Duty cycling the use of the radiometers tracks degradation of the nickel-phosphorous absorptive black radiometer interiors caused by solar exposure. Phase sensitive detection at the shutter frequency reduces noise and simplifies the estimate of the radiometer's equivalence ratio. An as-designed uncertainty budget estimates the instrument's accuracy goal. The TIM measurement equation defines the conversion from measured signal to solar irradiance.
Serum total antioxidant activity after myocardial infarction.
Miller, N J; Johnston, J D; Collis, C S; Rice-Evans, C
Serum total antioxidant activity (TAA), albumin and uric acid were measured on admission, and for the next 2 days in 56 patients suffering myocardial infarction, 20 of whom received streptokinase. The 'antioxidant gap', the difference between the serum TAA and the sum of the serum albumin and uric acid activity, was calculated. No significant changes in serum total antioxidant activity were observed in either group of patients between admission, day 1 and day 2. However, a decline in the 'antioxidant gap' after myocardial infarction was associated with a significantly higher mortality. PMID:9022893
Measuring Total and Germinable Spore Populations
NASA Astrophysics Data System (ADS)
Noell, A. C.; Yung, P. T.; Yang, W.; Ponce, A.; Lee, C.
It has been shown that bacterial endospores can be enumerated using a microscopy based assay that images the luminescent halos from terbium ions bound to dipicolinic acid, a spore specific chemical marker released upon spore germination. Further development of the instrument has simplified it towards automation while at the same time improving image quality. Enumeration of total spore populations has also been developed allowing measurement of the percentage of viable spores in any population by comparing the germinable/culturable spores to the total. Percentage viability will allow a more quantitative comparison of the ability of spores to survive across a wide range of extreme environments.
Estimating total momentum at finite distances
Gallo, Emanuel; Moreschi, Osvaldo M. [FaMAF Universidad Nacional de Cordoba, Ciudad Universitaria, (5000) Cordoba (Argentina); Lehner, Luis [Department of Physics and Astronomy, LSU, Baton Rouge, Louisiana 70803 (United States)
We study the difficulties associated with the evaluation of the total Bondi momentum at finite distances around the central source of a general (asymptotically flat) spacetime. Since the total momentum is only rigorously defined at future null infinity, both finite distance and gauge effects must be taken into account for a correct computation of this quantity. Our discussion is applicable in general contexts but is particularly relevant in numerically constructed spacetimes for both extracting important physical information and assessing the accuracy of additional quantities.
Management of complications after total shoulder arthroplasty.
Eichinger, Josef K; Galvin, Joseph W
The outcomes of total shoulder arthroplasty (TSA) for painful arthritis of the glenohumeral joint are excellent with significant improvement in pain and function. Increased use of total shoulder arthroplasty over the past decade has led to identification of common complications. Although the complication rate is low, accurate and timely diagnosis, appropriate management, and implementation of methods for prevention are critical to a successful long-term outcome. The most common complications include infection, glenoid and humeral component loosening, rotator cuff tear, periprosthetic fracture, and neurologic injury. The purpose of this review is to outline the best practices for diagnosing, managing, and preventing these complications. PMID:25672497
Biomechanics of reverse total shoulder arthroplasty.
Berliner, Jonathan L; Regalado-Magdos, Ashton; Ma, C Benjamin; Feeley, Brian T
Reverse total shoulder arthroplasty is an effective procedure for treatment of glenohumeral joint disease among patients with severe rotator cuff deficiency. Improvements in prosthetic design are the result of an evolved understanding of both shoulder and joint replacement biomechanics. Although modern generations of the reverse shoulder prosthesis vary in specific design details, they continue to adhere to Grammont's core principles demonstrated by his original Delta III prosthesis. This review article discusses the biomechanics of reverse total shoulder arthroplasty with a focus on elements of implant design and surgical technique that may affect stability, postoperative complications, and functional outcomes. PMID:25441574
Karl A. Stetson
This Letter reports a new technique for making holograms which employs a reference beam that is totally reflected from the air emulsion boundary of the hologram plate. This type of recording permits a very close spacing between the object and the hologram and has several interesting properties. The properties are listed and discussed in this Letter.
Strainrange partitioning: A total strain range version
NASA Technical Reports Server (NTRS)
Halford, G. R.; Saltsman, J. F.
Procedures are presented for expressing the Strainrange Partitioning (SRP) method for creep fatigue life prediction in terms of total strain range. Inelastic and elastic strain-range - life relations are summed to give total strain-range - life relations. The life components due to inelastic strains are dealt with using conventional SRP procedures while the life components due to elastic strains are expressed as families of time-dependent terms for each type of SRP cycle. Cyclic constitutive material behavior plays an important role in establishing the elastic strain-range - life relations as well as the partitioning of the inelastic strains. To apply the approach, however, it is not necessary to have to determine the magnitude of the inelastic strain range. The total strain SRP approach is evaluated and verified using two nickel base superalloys, AF2-1DA and Rene 95. Excellent agreement is demonstrated between observed and predicted cyclic lifetimes with 70 to 80 percent of the predicted lives falling within factors of two of the observed lives. The total strain-range SRP approach should be of considerable practical value to designers who are faced with creep-fatigue problems for which the inelastic strains cannot be calculated with sufficient accuracy to make reliable life predictions by the conventional inelastic strain range SRP approach.
Student Involvement: A Bridge to Total Education.
ERIC Educational Resources Information Center
North Carolina State Dept. of Public Instruction, Raleigh.
This document, prepared by students involved in the Task Force on Student Involvement program, provides guidelines for administrators who are attempting to enhance constructive student participation in the total educational program. An outline of specific recommendations for dealing with high school unrest is followed by general recommendationsģ
The benefits of total quality management
H. P. A. Geraedts; R. Montenarie; P. P van Rijk
In this article, we will review the implementation of the ISO 9000 quality system in the Department of Nuclear Medicine. We will also discuss the benefits of working with the ISO 9000 standards and explain why we have shifted our focus from ISO 9000 towards the EFQM model. After an introduction concerning Total Quality Management and the EFQM model, we
Implementing Total Quality Management in Construction Firms
Low Sui Pheng; Jasmine Ann Teo
As building projects get larger and more complex, clients are also increasingly demanding higher standards for their delivery. Total quality management ~TQM! has been recognized as a successful management philosophy in the manufacturing and service indus- tries. TQM can likewise be embraced in the construction industry to help raise quality and productivity. Two case studies of construction companies showed how
Starting Total Quality Management from ISO 9000
Michael Bradley
Some 20,000 companies have been registered as working to the International Quality Management Standard ISO 9000, but many have not achieved the improvements in their operations that can be obtained from managing on total quality management principles. ISO 9000 can be an excellent start to TQM, if it is interpreted in a way that encourages the company to start on
Total Quality Management: The Emperor's Tailor.
ERIC Educational Resources Information Center
Alexander, Gary C.; Keeler, Carolyn M.
Conversations among educators, business leaders, legislators, and educational reformers have generated support for the application of Total Quality Management (TQM) to education. This paper considers whether TQM is indeed the solution to education's problems. After a brief explanation of TQM theory, the paper is organized around four broad issuesģ
Abel inversion using total-variation regularization
T. J. Asaki; R. Chartrand; K. R. Vixie; B. Wohlberg
In the case of radiography of a cylindrically symmetric object, the Abel transform is useful for describing the tomographic measurement operator. The inverse of this operator is unbounded, so regularization is required for the computation of satisfactory inversions. We introduce the use of the total variation seminorm for this purpose, and prove the existence and uniqueness of solutions of the
Concentration[mg/L] Total Phosphorous
Mountziaris, T. J.
Water Quality Standards (mg/L) References Ę ASCE BMP database http://bmpdatabase.org/ Ę USEPA (1988., Hobson,P., 2010, International Stormwater Best Management Practices Database Pollutant Category Summary.8 Concentration[mg/L] Total Phosphorous Comparison of Best Management Practice performance for nutrient removal
To the theory of total reflection
NASA Astrophysics Data System (ADS)
Fedorov, Fedor I.
Not Available Fedorov F I 1955 To the theory of total reflection Doklady Akademii Nauk SSSR, 105, # 3, 465-8 received 9 December 1949. Presented by academician Lebedev A A on 27 May 1955. Translated by D I Pustakhod 2012.
A Campus Is a Total Community.
ERIC Educational Resources Information Center
Hunt, Robert E.
Described are the various components of the total college or university community and their associated environmental health and safety problems. Included are food service, insect and rodent control, multi-use athletic facilities, housing, laboratory animal facilities, laboratory biosafety, radiological health, fire protection, and emergencyģ
Total Quality Management. ERIC Digest, Number 73.
ERIC Educational Resources Information Center
Weaver, Tyler
The Japanese success story has made W. Edwards Deming's Total Quality Management (TQM) theory increasingly popular among American managers, from car manufacturers to educational leaders. TQM is based on two tenets: the primacy of customer satisfaction and the necessity of tapping nontraditional sources (especially employee ideas) to instituteģ
Enantioselective total synthesis of aspergillide C.
Nagasawa, Tomohiro; Kuwahara, Shigefumi
The first enantioselective total synthesis of aspergillide C, a cytotoxic 14-membered macrolide isolated from the marine-derived fungus Aspergillus ostianus, has been accomplished from a commercially available chiral glycidol derivative by a 12-step sequence involving an expeditious preparation of a cyclic acetal intermediate and a trans-selective Ferrier-type two-carbon homologation reaction. PMID:19128025
Curriculum Transformation through Total Quality Management.
ERIC Educational Resources Information Center
Edwards, Barbara; Algozzine, Bob
Describes a massive cultural transformation project at two Charlotte, North Carolina, elementary schools that used Deming's total quality management principles to restructure curricula according to Boyer's eight commonalities of learning. Shows how the FADE (focus, analyze, develop, and execute) model was used to develop a well-coordinated,ģ
Transforming Schools through Total Quality Education.
ERIC Educational Resources Information Center
Schmoker, Mike; Wilson, Richard B.
Deming's work emphasizes advantages of teamwork, investment in ongoing training for all employees to increase their value to the company, and insistence that research and employee-gathered data guide and inform every decision and improvement effort. The parallel between psychologist Mihaly Csikszenmihalyi's work and Deming's shows that Totalģ
First Name: Total Number of Pieces Submitted
Adali, Tulay
First Name: Last Name: Email: Total Number of Pieces Submitted: ARTWORK SUBMISSION FORM TWO. Submit your files on a CD or DVD and attach this form to the outside of the case or sleeve with your name on the CD or DVD. Please include your name and the title of work in the file name. The submission deadline
Endocrine deficit after fractionated total body irradiation.
Ogilvy-Stuart, A L; Clark, D J; Wallace, W H; Gibson, B E; Stevens, R F; Shalet, S M; Donaldson, M D
Endocrine function was assessed in 31 children (17 boys) after fractionated total body irradiation used in the preparative regimen for bone marrow transplantation. Endocrine dysfunction was present in 25 children. Fifteen of 29 had growth hormone insufficiency 0.9-4.9 years after total body irradiation, yet only three of the 15 had received previous cranial irradiation. Five of 30 had thyroid dysfunction: two with a low thyroxine and raised thyroid stimulating hormone (TSH) concentration and three with a raised TSH and normal thyroxine concentration. Thus the incidence of thyroid dysfunction (16%) is much lower than that reported after single fraction total body irradiation (39-59%). In only two children were abnormalities of the hypothalamic-pituitary-adrenal axis demonstrated. The majority of pubertal children assessed (n = 15) showed evidence of gonadal damage. All the pubertal girls (n = 5) had ovarian failure, although there was evidence of recovery of ovarian function in one girl. All seven boys in late puberty showed evidence of damage to the germinal epithelium, and two of three in early puberty had raised follicle stimulating hormone concentrations. Despite the use of a fractionated total body irradiation regimen, endocrine morbidity is substantial and children undergoing such procedures will require long term endocrine review and management. PMID:1417055
Measurement growth in a total quality perspective
G. B Rossi; P Salieri; S Sartori
Measurement is a key decision tool for a sustainable growth. In order to cope with this goal, total quality of measurement should be pursued at all operative levels, ranging from company or laboratory, through national and macro-regional levels, up to an international dimension. In the paper, a framework for achieving required measurement quality is proposed and discussed. For each operation
First asymmetric total synthesis of (+)-sparteine.
Smith, Brenton T; Wendt, John A; Aubķ, Jeffrey
[reaction: see text] The total synthesis of (+)-sparteine was accomplished from 2,5-norbornadione in 15 steps and 15.7% overall yield. The key steps were two ring-expansion reactions, one involving an intramolecular Schmidt reaction and one using a novel variant of the photo-Beckmann rearrangement. PMID:12123380
Courses Credit Hours Total Credit Hours
Mohaghegh, Shahab
Courses Credit Hours Total Credit Hours Hrs Attempted Hrs Completed Semester GPA Overall GPA Date are requesting to register for more than 20 credit hours during the fall/spring and more than 14 credit hours and approval from the Assistant/Associate Dean. For requests to register for more than 21 credit hours during
Rock around Tahoe Total Time: 25 Minutes
Schladow, S. Geoffrey
Rock around Tahoe Total Time: 25 Minutes Objectives Students will: 1. Get a sense of the rock cycle as a continuing process. 2. Explore Tahoe examples of the rock cycle in action. Background Like most Earth materials, rocks are created and destroyed in cycles. The rock cycle is a model that describes the ongoing
Total Synthesis of (-)-Nodulisporic Acid D.
Zou, Yike; Melvin, Jason E; Gonzales, Stephen S; Spafford, Matthew J; Smith, Amos B
A convergent total synthesis of the architecturally complex indole diterpenoid (-)-nodulisporic acid D has been achieved. Key synthetic transformations include vicinal difunctionalization of an advanced ?,?-unsaturated aldehyde to form the E,F-trans-fused 5,6-ring system of the eastern hemisphere and a cascade cross-coupling/indolization protocol leading to the CDE multisubstituted indole core. PMID:26029849
Total Revenue: $1,918,640 Scholarships
Rosen, Jay
Total Revenue: $1,918,640 Scholarships 45.03% General & Administrative 6.41% Grant Distributions 48 incentive grant and the $220,000 Henry Luce Foundation World Pathways Heritage Language grant n Launched Company, LLC Mr. Nick Lugo Nick Lugo Travel & N.Y. City Hispanic Chamber of Commerce Inc. Mr. Mario J
Total synthesis: Towards artificial terpene cyclases
NASA Astrophysics Data System (ADS)
Willot, Matthieu; Christmann, Mathias
The plant-derived sesquiterpene englerin A is a potent inhibitor of several renal cancer cell lines. Two recent total syntheses have utilized cationic gold(I)-complexes to coax readily available open-chain precursors into englerin's challenging oxotricyclic core with enzyme-like precision.
Distributed Education 23,606 Total Enrollments
Rock, Chris
a grant from the Texas Workforce Commission to provide a total of 80 scholarships to students ages 14 enrollments have increased 32% since fall 2009. Current enrollment for the program is at 111. Grants and Scholarships Ę University College awarded more than $30,000 in scholarships for fall 2010. Seven students
Total quality management and new product development
S. M. Boyer
Mitel Semiconductor (UK) designs and manufactures in volume a range of complex electronic modules for both Mitel Telecom and the external marketplace. These modules are custom products built on requests to specific customer requirements. Prototype development lead times are critical to gaining new business, short lead times offering significant competitive advantage. This paper describes the application of total quality management
Total pressing Indonesian gas development, exports
Not Available
Total is on track to become Indonesia's leading gas exporter by the turn of the century. Total's aggressive development of its Mahakam Delta acreage in East Kalimantan is intended to keep pace with growing liquefied natural gas demand, mainly from Japan but also increasingly from South Korea and Taiwan. A frantic scramble is under way among natural gas suppliers in the Pacific Rim region, particularly those with current LNG export facilities, to accommodate projections of soaring natural gas demand in the region. Accordingly, Total's Indonesian gas production goal is the centerpiece of a larger strategy to become a major player in the Far East Asia gas scene. Its goals also fall in line with Indonesia's. Facing flat or declining oil production while domestic oil demand continues to soar along with a rapidly growing economy, Indonesia is heeding some studies that project the country could become a net oil importer by the turn of the century. The paper describes Total's Far East strategy, the Mahakam acreage which it operates, the shift to gas development, added discoveries, future development, project spending levels, and LNG export capacity.
The Total Solar Eclipse, March 1970
ERIC Educational Resources Information Center
Glenn, William H.
Describes the circumstances of the total and partial solar eclipse of March 7, 1970 in certain American cities. Also discussed are (1) a classroom demonstration of the cause of solar eclipses, (2) techniques for safely observing the eclipse, and (3) what to observe during the eclipse. Bibliography. (LC)
Total Quality Management in Higher Education.
ERIC Educational Resources Information Center
Rieley, James B.
In order for an educational institution to utilize Total Quality Management as a tool for improving effectiveness, the culture of the college must foster a belief in change and a focus on the customer. A disciplined approach to planning and a commitment to the concept of Continuous Improvement (CI) are also required. Concerning acceptance ofģ
Implications of Total Quality Management in Education.
ERIC Educational Resources Information Center
Wiedmer, Terry L.; Harris, Vicki L.
Total Quality Management in Education is a systems model that involves internal and external stakeholders in developing practices, establishing partnership teams, enhancing individual growth, and increasing communication. Walk the Talk in Texas is an example of successful application of the model. (SK)
Scope on the Skies: Total lunar eclipse
NSDL National Science Digital Library
Bob Riddle
In the hours before the December solstice, the full Moon will pass through the Earth's shadow for a total lunar eclipse that will be visible at some point from all of North America. Depending on your longitude and time zone, this event will be visible any
Periprosthetic fractures around total knee arthroplasty
Sarmah, SS; Patel, S; Reading, G; El-Husseiny, M; Douglas, S; Haddad, FS
INTRODUCTION The number of total knee arthroplasties performed continues to rise annually and it would be expected that complications, which include periprosthetic fractures, will also therefore become more commonplace. This article reviews the current literature regarding this injury and identifies the treatment principles that enable patients to regain optimal function. METHODS A comprehensive search of the Pubmed and EmbaseÖ databases was performed to identify relevant articles. Keywords and MeSH (Medical Subject Headings) terms included in the search strategy were æperiprosthetic fracture(s)Æ, æfemurÆ, ætibiaÆ, æpatella(r)Æ, æcomplication(s)Æ, æfailure(s)Æ, ærisk(s)Æ, æprevalenceÆ, æincidenceÆ, æepidemiologyÆ and æclassification(s)Æ. The search was limited to all articles published in English and reference lists from the original articles were reviewed to identify pertinent articles to include in this review. A total number of 43 studies were identified. RESULTS Common treatment aims have been identified when managing patients with a periprosthetic fracture around total knee arthoplasty. The main criterion that determines which option to choose is the degree of remaining bone stock and the amount of fracture displacement. CONCLUSIONS Treatment of a periprosthetic fracture around total knee arthroplasty will either be non-operative, osteosynthesis or revision arthroplasty. It is imperative that a suitable option is chosen and based on the published literature, pathways are outlined to aid the surgeon. PMID:22943223
The project will develop and implement a monitoring system for measuring total and dissolved organic carbon in the Sacramneto and San Joaquin Delta system. Current carbon monitoring data is measured every 6 hours and data was posted once per week. It was also indicated that resul...
Recent Developments in Total Variation Image Restoration
Esedoglu, Selim
Recent Developments in Total Variation Image Restoration T. Chan S. Esedoglu F. Park A. Yip for image restoration. More recently, there has been a resurgence of interest and exciting new develop of restoration problems, and remain one of the most active areas of research in mathematical image processing
Impaction bone grafting for total hip revision
Donald R. Gore
We used impaction bone grafting for total hip revision on 26 hips in 25 patients. Average patient age was 68 (34-89) years, and average duration from last surgery was 9 years. In all cases morselized allograft bone was used for the graft, and the femoral component was a collarless, polished, tapered stem. Average duration of surgery was 2.4 h, intraoperative
Nonlinear total variation based noise removal algorithms
Leonid I. Rudin; Stanley Osher; Emad Fatemi
A constrained optimization type of numerical algorithm for removing noise from images is presented. The total variation of the image is minimized subject to constraints involving the statistics of the noise. The constraints are imposed using Lagrange multipliers. The solution is obtained using the gradient-projection method. This amounts to solving a time dependent partial differential equation on a manifold determined
Coordinating Council. Ninth Meeting: Total Quality Management
NASA Technical Reports Server (NTRS)
This report summarizes the 9th meeting of the STI Coordinating Council. The council listened to the speakers' understanding of Total Quality Management (TQM) principles and heard stories of successful applications of these principles. Definitions of quality stated were focused on customer satisfaction. Reports presented by the speakers are also included.
Total Quality Management in Libraries: A Sourcebook.
ERIC Educational Resources Information Center
O'Neil, Rosanna M., Comp.
Total Quality Management (TQM) brings together the best aspects of organizational excellence by driving out fear, offering customer-driven products and services, doing it right the first time by eliminating error, and maintaining inventory control without waste. Libraries are service organizations which are constantly trying to improve service.ģ
Application of Total Quality Management in Education
ERIC Educational Resources Information Center
Farooq, M. S.; Akhtar, M. S.; Ullah, S. Zia; Memon, R. A.
The purpose of the paper is to analyzing thoughts of the modern management paradigm "Total Quality Management" (TQM), and its application in the field of education. The basic theme of TQM is participatory approach to address the question(s) of quality in business aswell as in the field of education. Reviewing fresh literature from the internet ģ
Total Quality Management (TQM) in Higher Education.
ERIC Educational Resources Information Center
Sullivan, Michael F.
This document consists largely of paper versions of the transparencies used by the author to give his conference paper on Total Quality Management (TQM) in the college and university setting. An introduction lists a series of definitional phrases, a list of what TQM is not, and 11 fundamental principles describing what TQM is. The three majorģ
Solar collector using total internal reflectance
G. R. Johnson; M. G. Miles; I. O. Salyer; E. E. Hardy
A solar collector is constructed of a photoelectric cell mounted within a collector of the total internal reflectance type. The photoelectric cell has the form of a rod of a monocrystalline element or compound with a generally cylindrical junction spaced at a distance radially inwardly from the outer surface of the rod. The photoelectric cell is mounted within a trough
Quantities of all forms of energy consumed for collection and treatment of municipal wastewater are estimated. Heat energy is equated to electrical energy by a conversion factor of 10,500 Btu/kwh. Total energy consumption, expressed as kwh/mg of wastewater treated, ranges from 23...
The paper discusses a procedure for estimating permanent total enclosure (PTE) costs. (NOTE: Industries that use add-on control devices must adequately capture emissions before delivering them to the control device. One way to capture emissions is to use PTEs, enclosures that mee...
Six Foundations of Total Quality Management.
ERIC Educational Resources Information Center
Lozier, G. Gregory; Teeter, Deborah J.
Understanding the principles underlying the Total Quality Management approach is essential to using it effectively in higher education. These include establishing a customer-focused mission; creating a vision; improving the process continuously; using systematic analysis; promoting participation; and recognizing the college or university as aģ
Invariant Ordering of Item-Total Regressions
ERIC Educational Resources Information Center
Tijmstra, Jesper; Hessen, David J.; van der Heijden, Peter G. M.; Sijtsma, Klaas
A new observable consequence of the property of invariant item ordering is presented, which holds under Mokken's double monotonicity model for dichotomous data. The observable consequence is an invariant ordering of the item-total regressions. Kendall's measure of concordance "W" and a weighted version of this measure are proposed as measures forģ
Early Feeding After a Total Abdominal Hysterectomy
Mary Flesher; Brenda Wagner; Lyn Jones
Background: Oral fluids and food are traditionally introduced slowly after total abdominal hysterectomy (TAH). This descriptive study examined the effect and tolerance of early oral intake following this surgery. Methods: A retrospective chart review was conducted on 164 patients who had been on a clinical pathway following TAH. Comparisons in initiation of fluids and foods, and gastrointestinal effects were made
Revitalizing Space Operations through Total Quality Management
NASA Technical Reports Server (NTRS)
Baylis, William T.
The purpose of this paper is to show the reader what total quality management (TQM) is and how to apply TQM in the space systems and management arena. TQM is easily understood, can be implemented in any type of business organization, and works.
Long-term variation of total ozone
R. P. Kane
The long-term variation of total ozone is studied for 1957 up to date for different latitude zones. The 3-year running averages show that, apart from a small portion showing parallelism with sunspot cycles, the trends in different latitude zones are dissimilar. In particular, where northern latitudes show a rising trend, the southern latitudes show an opposite (decreasing) trend. In the
The importance of the anterior longitudinal ligament in lumbar disc arthroplasty: 36-Month follow-up experience in extreme lateral total disc replacement
Marchi, Luis; Oliveira, Leonardo; Coutinho, Etevaldo; Pimenta, Luiz
Background Current total disc replacement (TDR) for lumbar spine requires an anterior approach for implantation but presents inherent limitations, including risks to the abdominal structures, as well as resection of the anterior longitudinal ligament. By approaching the spine laterally, it is possible to preserve the stabilizing ligaments, which are a natural restraint to excessive rotations and translations, and thereby help to minimize facet stresses. This less invasive approach also offers a biomechanical advantage of placement of the device over the ring apophysis bilaterally; importantly, it also offers a greater opportunity for safer revision surgery, if necessary, by avoiding scarring of the anterior vasculature. We present the clinical and radiologic results of a lateral TDR device from a prospective single-center study. Methods A new metal-on-metal TDR device designed for implantation through a true lateral, retroperitoneal, transpsoatic approach (extreme lateral interbody fusion) was implanted in 36 patients with discography-confirmed 1- or 2-level degenerative disc disease. Clinical (pain and function) and radiographic (range of motion) outcome assessments were prospectively collected preoperatively, postoperatively, and serially up to a minimum of 36 monthsÆ follow-up. Results Between December 2005 and December 2006, 36 surgeries were performed in 16 men and 20 women (mean age, 42.6 years). These included 15 single-level TDR procedures at L3-4 or L4-5, 3 2-level TDR procedures spanning L3-4 and L4-5, and 18 hybrid procedures (anterior lumbar interbody fusion) at L5-S1 and TDR at L4-5 (17) or L3-4 (1). Operative time averaged 130 minutes, with mean blood loss of 60 mL and no intraoperative complications. Postoperative X-rays showed good device placement, with restoration of disc height, foraminal volume, and sagittal balance. All patients were up and walking within 12 hours of surgery, and all but 9 were discharged the next day (7 of those 9 were hybrid TDR¢anterior lumbar interbody fusion cases). Postoperatively, 5 of 36 patients (13.8%) had psoas weakness and 3 of 36 (8.3%) had anterior thigh numbness, with both symptoms resolving within 2 weeks. Of the 36 patients, 4 (11%) had postoperative facet joint pain, all in hybrid cases. Visual analog scale pain scores and Oswestry Disability Index scores improved by 74.5% and 69.2%, respectively, from preoperatively to 3-year follow-up. Range of motion at 3 years postoperatively averaged 8.1░. Signals of heterotopic ossification were present in 5 patients (13.9%), and 2 patients (5.5%) were considered to have fusion after 36 months. Conclusions The clinical and radiographic results of a laterally placed TDR have shown maintenance of pain relief and functional improvement over a long-term follow-up period. The benefits of the lateral accessŚminimal morbidity, avoidance of mobilization of the great vessels, preservation of the anterior longitudinal ligament, biomechanically stable orientation, and broader revision optionsŚpromote a new option for motion-preservation procedures. PMID:25694866
Is a totally implantable artificial heart realistic?
Nosķ, Y
The incidence of local infection that occurred after the implantation of the intrathoracic Jarvik 7 total artificial heart (J-7 TAH) in patients was a major problem of this cardiac prosthesis. Infection rates increased when the J-7 TAH was implanted for longer periods of time, which was contrary to the results that were obtained by the implantation of the left ventricular assist devices (LVAD) either in the abdominal cavity or in the abdominal wall. Currently, the general belief is that the implantation of a cardiac prosthesis inside of the chest cavity is not safe, due to higher rates of infection. Thus, Part I of this paper deals with the question: "Is a total artificial heart physiologically acceptable?" We believe structural differences of the J-7 TAHs and other LVADs are an important part of the problem. The J-7 TAH is a volumetrically dynamic pump, and the other LVADs are a volumetrically fixed stationary pump. Based upon experiences of this investigator, intrathoracic implantation of a smooth surface pulsating device (or a volumetrically dynamic pump) generated persistent local inflammatory reactive tissues directly adjacent to the device. These tissue capsules were nonadherent to the device, and therefore may produce an ideal environment for allowing bacteria to grow. The findings were opposite to those for a non-pulsating surface pump inside the chest cavity. Part II of this paper discusses the question: "Is a totally implantable artificial heart technically achievable?" Many technical problems for the totally implantable TAH were already resolved during the development program of the totally implantable LVAD. However, there are three TAH specific problems that remain to be solved before achieving a clinically useful totally implantable TAH system. They are (a) anatomical compatibilities of the TAH system; (b) reliable control of the TAH system, (c) reliable and effective long-term operation of the TAH system. We have resolved the anatomical problem by the integral design of the pump-actuator system. Overall size of the hard shell Baylor TAH system is 510 cm3 with a diameter of 97 mm and a width of 82 mm. Its stoke volume was reduced to 63 cm3. The stable and reliable control of TAH performances was established by the three sets of Hall effect sensors with left master alternate mode of pumping. No physiological parameter was used as a feedback signal. Reliable long-term operation of the TAH system was established by the electromechanical actuation system. A simple drive mechanism with commercially available components and subsystems was used.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:1300099
Autonoma de Madrid, Universidad
Observation of the total solar eclipsis. L'observation des eclipses totales solaires
Koutchmy, S.
A brief historical account of the solar-total-eclipses events is presented to show their importance, including their use for the scientific analysis of the solar corona, since 1848. The main parameters and a schema of the eclipses are given. Several examples of investigations performed during a solar total eclipse are discussed.
Evaluation of the Totally Cool, Totally Art Program, Austin Parks and Recreation Department.
ERIC Educational Resources Information Center
Witt, Peter A.
The "Totally Cool, Totally Art Program" (TCTA) was initiated by the Austin (Texas) Parks and Recreation Department in the fall of 1996. Through the TCTA program, visual arts classes were offered to teens twice a week at each of nine recreation centers. At eight of the nine sites, six separate 4-week sessions were held, with three sessions at theģ
Effectiveness of clinical pathways for total knee and total hip arthroplasty
Stephen Kim; Elena Losina; Daniel H. Solomon; John Wright; Jeffrey N. Katz
Although many hospitals have implemented clinical pathways to standardize the process of care, the effectiveness of clinical pathways for total hip and knee arthroplasties has not been reviewed critically. We searched for articles comparing outcomes of total hip or knee arthroplasty for patients who were treated using clinical pathways as opposed to patients treated without these pathways. Eleven studies met
Frustrated total internal reflection acoustic field sensor
Kallman, Jeffrey S. (Pleasanton, CA)
A frustrated total internal reflection acoustic field sensor which allows the acquisition of the acoustic field over an entire plane, all at once. The sensor finds use in acoustic holography and acoustic diffraction tomography. For example, the sensor may be produced by a transparent plate with transparent support members tall enough to support one or more flexible membranes at an appropriate height for frustrated total internal reflection to occur. An acoustic wave causes the membrane to deflect away from its quiescent position and thus changes the amount of light that tunnels through the gap formed by the support members and into the membrane, and so changes the amount of light reflected by the membrane. The sensor(s) is illuminated by a uniform tight field, and the reflection from the sensor yields acoustic wave amplitude and phase information which can be picked up electronically or otherwise.
Acute pasteurella multocida in total knee arthroplasty.
Stiehl, James B; Sterkin, Lawrence A; Brummitt, Charles F
Pasturella multocida is a rare cause of joint sepsis in total joint arthroplasty, and all case reports have identified a distant source of infection from an animal bite that has caused potential hematogenous seeding of the prosthesis. We report a case in which no potential distal wound source was found and the only likely etiology was local wound seeding from an old injury. In that injury, a saddle stirrup had caused a severe traumatic soft tissue injury as a horse had rolled over the patient. We draw attention to the fact that this particular bacteria is virulent in producing septic contamination of a total joint prosthesis, and aggressive treatment is indicated when such infection is identified. PMID:14973872
Metallosis in a total knee arthroplasty.
Vivegananthan, Bhairavi; Shah, Rohi; Karuppiah, A S; Karuppiah, S V
A 70-year-old woman presented with right knee pain and a 'grinding' sensation 6 months after a total knee replacement for osteoarthritis. Clinical examination revealed a valgus deformity, patellofemoral crepitus and a reduced knee flexion. Radiographs revealed distinctive findings including the 'bubble sign', 'cloud sign' and the 'metal line sign', which are diagnostic of metallosis. Metallosis is an uncommon complication of total joint replacements, where bone and periprosthetic soft tissues are infiltrated by metallic debris from wearing of the prostheses. This usually occurs in high-wear joints such as hips and knees. Treatment for patients diagnosed with metallosis is synovectomy and a revision surgery. Our patient underwent revision surgery 5 years after her initial surgery. PMID:24642179
Feminist leadership through total quality management.
Lanza, M L
Feminist leadership in nursing can be achieved through Total Quality Management. Total Quality Management (TQM) is a philosophy and technology that represents the foundation of a continuously improving organization. The feminist leadership ideas practiced by nurses, such as empowering staff and decision by consensus, are also central to TQM. Feminist leadership utilizing TQM enables employees to creatively contribute to the system without fear or intimidation. Employees at all levels in the organization are then empowered. The role of the feminist leader using TQM is one of facilitator rather than authority figure. Feminist leadership in nursing can spearhead the opportunity for improvement to provide high-quality, cost-effective health care in a troubled and complex economic environment. PMID:9119786
Total quality management: achieving service excellence.
Adelson, R
Total Quality Management (TQM) provides a philosophy and a method for organizational renewal and redesign. It is based on the principle that productive work is accomplished through processes. Improving these processes requires the office team to objectively measure performance, discover root causes of problems, take corrective action, determine the effect of these actions, and secure achievements. TQM is a technique that provides a series of steps and set of tools. Through staff involvement and a desire for quality improvement, organizations involved in total quality note the accompanying satisfaction in taking constructive action, improving patient relations, and achieving service excellence. In today's competitive delivery environment, implementation of TQM can result in more satisfied patients, higher staff morale, and a more effective office team. PMID:9161134
Increasing productivity through Total Reuse Management (TRM)
NASA Technical Reports Server (NTRS)
Schuler, M. P.
Total Reuse Management (TRM) is a new concept currently being promoted by the NASA Langley Software Engineering and Ada Lab (SEAL). It uses concepts similar to those promoted in Total Quality Management (TQM). Both technical and management personnel are continually encouraged to think in terms of reuse. Reuse is not something that is aimed for after a product is completed, but rather it is built into the product from inception through development. Lowering software development costs, reducing risk, and increasing code reliability are the more prominent goals of TRM. Procedures and methods used to adopt and apply TRM are described. Reuse is frequently thought of as only being applicable to code. However, reuse can apply to all products and all phases of the software life cycle. These products include management and quality assurance plans, designs, and testing procedures. Specific examples of successfully reused products are given and future goals are discussed.
A Modern Approach to Total Wellbeing
NASA Astrophysics Data System (ADS)
Hadzic, Maja; Chen, Meifania; Brouwer, Rick; Dillon, Tharam
The events of the last decades have impacted our lives and our health significantly. We expected that the technology boom will improve our lives. While this may be true in a specific context, generally speaking our societies are suffering from moral decays, terrorism fears, wars, financial crisis and unpredictable acts of nature that are increasing in frequency and in intensity. The complex nature of the world we live is impacting our health and wellbeing considerably. Our health is not only determined by our physical health but is the end product of the interplay of the physical, mental, emotional, financial, relational and spiritual events of a lifetime. In this paper we develop a framework that will help us define and measure total wellbeing of individuals in our volatile societies. This framework will help us better understand the complex nature of total wellbeing and develop effective prevention and intervention strategies.
Enantioselective formal total synthesis of (+)-aspergillide C.
Panarese, Joseph D; Waters, Stephen P
An enantioselective formal total synthesis of the cytotoxic macrolide (+)-aspergillide C has been accomplished from (S)-(-)-glyceraldehyde acetonide and the Danishefsky-Kitahara diene. Strategic transformations include a hetero Diels-Alder reaction, Ferrier-type addition, and palladium-catalyzed oxidative lactonization to set key stereocenters within the dihydropyran core, followed by fragment coupling via (E)-selective Julia-Kocienski olefination. PMID:19817392
Science, specific knowledge, and total quality management
Karen Hopper Wruck; Michael C. Jensen
We analyze Total Quality Management (TQM) from an economic and organizational perspective. We find that TQM is a new organizing technology that is science-based, non-hierarchical, and non-market-oriented. It improves productivity by encouraging the use of science in decision-making and discouraging counter-productive defensive behavior. It also encourages effective creation and use of specific knowledge throughout the organization. Effective implementation of TQM
Abel inversion using total variation regularization: applications
Thomas J. Asaki; Patrick R. Campbell; Rick Chartrand; Collin E. Powell; Kevin R. Vixie; Brendt E. Wohlberg
We apply total-variation (TV) regularization methods to Abel inversion tomography. Inversions are performed using the fixed-point iteration method and the regularization parameter is chosen such that the resulting data fidelity approximates the known or estimated statistical character of the noisy data. Five one-dimensional (1D) examples illustrate the favorable characteristics of TV-regularized solutions: noise suppression and density discontinuity preservation. Experimental and
Total Building Air Management: When Dehumidification Counts
Chilton, R. L.; White, C. L.
TOTAL BUILDING AIR MANAGEMENT: WHEN DEHUMIDIFICATION COUNTS Robert L. Chllton Vice President Sales ClimateMaster, hc. Oklahoma City, Oklahoma ABSTRACT Industry trends toward stringent indoor air quality codes, spearheaded by ASHRAE 62... STUDY OVERVIEW The project described in this paper is a 200,000 square foot supercenter located in Moore, Oklahoma. Within the building envelope are contained a complete super market and a retail store with a full range of household goods, dry...
Total synthesis of insect antifeedant drimane sesquiterpenes
B. J. M. Jansen
The investigations described in this thesis deal with the total synthesis of sesquiterpenes of the drimane family, named for their widespread occurrence in the stem bark of South American Drimys species. These compounds contain the bicyclofarnesol nucleus 1<\\/strong> , which is invariably oxidized at C-11 and\\/or C-12 and often at other sites as well (see figure 8.1).
Optimal Total Exchange in Anonymous Cayley Graphs
NASA Astrophysics Data System (ADS)
Oh, Sanghoun; Mohamed, Adnan; Jeon, Moongu
Total exchange or all-to-all personalized communication problem is that each node in a network has a message to be sent to every other node. To solve this communication problem, we present a time-optimal algorithm in anonymous Cayley graphs as assuming a single-port full duplex model in which every node is able to send and receive at most one message in each time unit.
NASA total quality management 1990 accomplishments report
NASA Technical Reports Server (NTRS)
NASA's efforts in Total Quality Management are based on continuous improvement and serve as a foundation for NASA's present and future endeavors. Given here are numerous examples of quality strategies that have proven effective and efficient in a time when cost reduction is critical. These accomplishment benefit our Agency and help to achieve our primary goal, keeping American in the forefront of the aerospace industry.
Total records management: the TMI example
Kocsis, F.J. III; Hegstrom, K.L.
The TMI-2 accident of March 28, 1979 resulted in the asking of major questions about nuclear technology. The Technical Information and Examination Program (TI and EP) was established to collect the answers to these questions and to transfer the information to the nuclear community. This presentation discusses the development and implementation of a total records management system necessitated by the requirements for recovery of TMI-Unit 2.
[Obturator externus impingement after total hip replacement].
M³ller, M; Perka, C; Tohtz, S
A patient with a painful total hip replacement that is not obviously loose presents a diagnostic challenge. One of the rare causes is psoas impingement syndrome. Because there are several periarticular muscles, further muscle impingements are possible. We report on a case of painful obturator externus muscle impingement on the acetabular cup. On magnetic resonance imaging, a pathologic contact between the obturator externus muscle and the caudal rim of the cup was seen. A positive injection confirmed the pathologic contact. PMID:19680628
Minnows can acclimate to total residual chlorine
Joseph William Lotts; Arthur Jay Stewart
Observations in a chlorine-contaminated stream in eastern Tennessee revealed several species of fish in areas where total residual chlorine (TRC) concentrations were often great enough to be lethal, based on the results of other studies. The authors used in situ and laboratory experiments to test the hypothesis that minnows could acclimate to TRC. Acclimation was assessed by time-to-death for fish
Total synthesis of enantiopure potassium aeshynomate.
Rizos, Stergios R; Stefanakis, John G; Kotoulas, Stefanos S; Koumbis, Alexandros E
Potassium aeshynomate (1) is the leaf-opening factor of the nyctinastic plant Aeshynomene indica L. In this article a convenient and efficient strategy for the total synthesis of enantiomerically pure 1 is described, starting from the l-arabinose derived chiron ent-6. The realized synthetic scheme involves a postcoupling oxidation approach and securely determines the absolute configuration of the targeted natural product, which remained unknown until now. PMID:24967505
Surgical navigation in canine total knee replacement
Peters, Kaleigh M.; Hutter, Erin; Siston, Robert A.; Bertran, Judith
Conference of the 404 Veterinary Orthopedic Society, The Canyons, Park City, UT. 405 [14] Tomlinson J, Fox D, Cook JL, et al. Measurement of femoral angles in four dog 406 breeds. Vet Surg 2007; 36:593-598. 407 [15] Dismukes DI, Tomlinson JL, Fox DB... , or amputation. The presence of bilateral 58 disease often makes these options less feasible due to contralateral stifle pathology. 59 Total knee replacement (TKR) is now an established treatment option for dogs with 60 severe osteoarthritis secondary...
Total lightning characteristics of ordinary convectionĀ
Motley, Shane Michael
. DATA AND METHODOLOGY??....?????????????........... 33 2.1 Lightning Detection and Ranging Network?????????......... 33 2.1.1 VHF Flash Data???????????????????..... 45 2.2 National Lightning Detection Network???????????....... 47 2.3 Radar Data...???????????????????????....... 127 4.1.2 Bimodal Distributions in VHF Source Densities??????........ 133 4.1.3 Flash Heights??????????????????.............. 134 4.1.4 Location of Upper Positive Charge Region????????........ 137 4.1.5 Correlations Between Total Flash...
Approaches for primary total hip replacement.
Ilchmann, Thomas
In total hip replacement surgeons can choose from a various number of approaches, from posterior, lateral or direct anterior. Excellent results can be achieved with all approaches and there is no evidence for the use of a specific approach. Minimally invasive operating techniques might further contribute to that success. Early rehabilitation and functional outcome can be improved by the introduction of evidence based clinical pathways irrespective to the used approach. PMID:24970034
Concise total synthesis of (▒)-actinophyllic acid
Granger, Brett A.; Jewett, Ivan T.; Butler, Jeffrey D.; Martin, Stephen F.
A concise total synthesis of the complex indole alkaloid (▒)-actinophyllic acid was accomplished by a sequence of reactions requiring only 10 steps from readily-available, known starting materials. The approach featured a Lewis acid-catalyzed cascade of reactions involving stabilized carbocations that delivered the tetracyclic core of the natural product in a single chemical operation. Optimal conversion of this key intermediate into (▒)-actinophyllic acid required judicious selection of a protecting group strategy. PMID:24882888
Total synthesis of norneolignans from Krameria species.
Seo, Pil-Ja; Choi, Hong-Dae; Son, Byeng-Wha
The total synthesis of nomeolignans isolated from Krameria species, 2-aryl-5-(E)-propenylbenzofurans (5, 11), is described. The key step involves the one-pot reaction for 2-arylbenzofurans (2, 7) from 4-hydroxyphenylacetone with 4'-acetoxy-2-chloro-2-(methylthio)acetophenone (1) and 2-chloro-2-methylthio-(2',4',6'-trimethoxy)acetophenone (6) under Friedel-Crafts reactionconditions. PMID:15646789
Biocompatibility of materials for total joint replacement.
Escalas, F; Galante, J; Rostoker, W
The clinical use of total joint prostheses demands absolute biocompatibility of the materials employed. The purpose of this experiment was the bioassay of some materials considered as possible candidates for use in total joint prostheses as load-bearing members or as wear-resistant surfaces. Some materials already in use were also tested. 316L stainless steel was used as a control. The materials were implanted as a standardized rod and in particulate form. An average of 12 samples per material were implanted in soft tissue for six months and a total of 145 rabbits were used in this study. Twenty-five materials including metals, polymers, and ceramics were tested in solid and powdered form. A semiquantitative evaluation of local tissue reaction and a study of organs was performed. Polymers and metallic materials showed in general a mild tissue reaction. Ceramics, which some authors describe as the best tolerated materials, elicited variable tissue responses. Some of these (glass-ceramics) presented very poor tissue tolerance. The least reactive, titanium oxide, titanium aluminate, and aluminum oxide, presented a degree of tissue reaction comparable to that of corrosion resistant metals, but not superior to them. Moderate reactivity was the general rule for particulate materials except for the Pyroceram glass-ceramics, polymides, and Teflon. Ultrahigh molecular weight polyethylene in particulate form elicited a rather cellular tissue response, a fact to be considered when projecting long-term results in total joint arthroplasty. No pathological changes compatible with systemic toxicity by materials tested were observed in the study of the organs. PMID:1254613
Asymmetric total synthesis of mycoleptodiscin?a.
Zhou, Shupeng; Chen, Hao; Luo, Yijie; Zhang, Wenhao; Li, Ang
The first total synthesis of mycoleptodiscin?A, a structurally unusual indolosesquiterpenoid possessing an ortho-benzoquinone motif, has been accomplished. A sulfone alkylation coupled two readily available fragments to give an aryl triene intermediate. The tetracyclic core of the molecule was assembled through a highly enantioselective iridium-catalyzed polyene cyclization. The benzylic homologation was achieved by a cationic cyanation. The indole motif was constructed via a copper-mediated intramolecular C?N bond formation at a late stage. PMID:25907827
The benefits of total quality management.
Geraedts, H P; Montenarie, R; van Rijk, P P
In this article, we will review the implementation of the ISO 9000 quality system in the Department of Nuclear Medicine. We will also discuss the benefits of working with the ISO 9000 standards and explain why we have shifted our focus from ISO 9000 towards the EFQM model. After an introduction concerning Total Quality Management and the EFQM model, we will describe how we have used the EFQM model to date and how we intend to implement TQM in the future. PMID:11137800
Assessing Operational Total Lightning Visualization Products
NASA Technical Reports Server (NTRS)
Stano, Geoffrey T.; Darden, Christopher B.; Nadler, David J.
In May 2003, NASA's Short-term Prediction Research and Transition (SPoRT) program successfully provided total lightning data from the North Alabama Lightning Mapping Array (NALMA) to the National Weather Service (NWS) office in Huntsville, Alabama. The major accomplishment was providing the observations in real-time to the NWS in the native Advanced Weather Interactive Processing System (AWIPS) decision support system. Within days, the NALMA data were used to issue a tornado warning initiating seven years of ongoing support to the NWS' severe weather and situational awareness operations. With this success, SPoRT now provides real-time NALMA data to five forecast offices as well as working to transition data from total lightning networks at Kennedy Space Center and the White Sands Missile Range to the surrounding NWS offices. The only NALMA product that has been transitioned to SPoRT's partner NWS offices is the source density product, available at a 2 km resolution in 2 min intervals. However, discussions with users of total lightning data from other networks have shown that other products are available, ranging from spatial and temporal variations of the source density product to the creation of a flash extent density. SPoRT and the Huntsville, Alabama NWS are evaluating the utility of these variations as this has not been addressed since the initial transition in 2003. This preliminary analysis will focus on what products will best support the operational warning decision process. Data from 19 April 2009 are analyzed. On this day, severe thunderstorms formed ahead of an approaching cold front. Widespread severe weather was observed, primarily south of the Tennessee River with multiple, weak tornadoes, numerous severe hail reports, and wind. This preliminary analysis is the first step in evaluation which product(s) are best suited for operations. The ultimate goal is selecting a single product for use with all total lightning networks to streamline training and science sharing.
On total dominating sets in graphs
Maryam Atapour; Nasrin Soltankhah
A set $S$ of vertices in a graph $G(V,E)$ is called a dominating set if every vertex $v\\\\in V$ is either an element of $S$ or is adjacent to an element of $S$. A set $S$ of vertices in a graph $G(V,E)$ is called a total dominating set if every vertex $v\\\\in V$ is adjacent to an element of $S$.
Total Synthesis of Hapalindoles J and U
Rafferty, Ryan J.; Williams, Robert M.
The total synthesis of D,L-hapalindoles J and U has been accomplished. Hapalindole J was prepared in 11% overall yield over eleven synthetic steps and hapalindole U was prepared in 25% overall yield over thirteen synthetic steps from commercially available materials. The route employs a novel silyl ether-based strategy for accessing the 6:5:6:6 ring system of the hapalindoles rapidly and in good yields. PMID:22126131
Total synthesis of hapalindoles J and U.
Rafferty, Ryan J; Williams, Robert M
The total synthesis of D,L-hapalindoles J and U has been accomplished. Hapalindole J was prepared in 11% overall yield over 11 synthetic steps and hapalindole U was prepared in 25% overall yield over 13 synthetic steps from commercially available materials. The route employs a novel silyl ether-based strategy for accessing the 6:5:6:6 ring system of the hapalindoles rapidly and in good yields. PMID:22126131
Mathematical evaluation of jumping distance in total hip arthroplasty
Lazennec, Jean Yves; Khiami, Frederic; Catonnķ, Yves
Background and purpose The jumping distance (JD) is the degree of lateral translation of the femoral head center required before dislocation occurs. The smaller the distance, the higher the theoretical risk of dislocation. The aim of our study was to evaluate this jumping distance and its variation according to the characteristics of the implant, and also the theoretical gain in using large head diameters of above 38 mm. Methods The JD was calculated as a function of the cup ante-version and abduction angles, the head diameter, and the head offset (defined as the distance between the center of the femoral head and the cup opening plane). Head diameters of 28, 32, 36, 40, 44 and 48 mm were analyzed. The abduction angle was increased from 0░ to 80░ with a 10░ increment. The anteversion angle was increased from 0░ to 40░ with a 5░ increment. Results The jumping distance was found to decrease as the cup abduction angle increased (0.25 mm each 1░ for 32-mm head diameter). It increased by 0.05 mm for a 1░ increase in the ante-version angle. The jumping distance increased as the head diameter increased (0.4 mm each mm diameter for a 45░ abduction angle). The net gain obtained by increasing the diameter, however, decreased when abduction angle increased (0.25 each mm diameter for 60░ abduction). The JD decreased by 0.92 mm for each 1-mm increase in head offset, showing that head offset was the most important parameter influencing the JD. Interpretation The theoretical gain in stability obtained by using a large femoral head (above 36 mm) is negligible in cases where there is a high cup abduction angle. An increase in offset of the femoral head substantially reduces the jumping distance and it should therefore be avoided. PMID:19421906
Improved selection in totally monotone arrays
Mansour, Y. (Harvard Univ., Cambridge, MA (United States). Aiken Computation Lab.); Park, J.K. (Sandia National Labs., Albuquerque, NM (United States)); Schieber, B. (International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center); Sen, S. (AT and T Bell Labs., Murray Hill, NJ (United States))
This paper's main result is an O(({radical}{bar m}lgm)(n lg n) + mlg n)-time algorithm for computing the kth smallest entry in each row of an m {times} n totally monotone array. (A two-dimensional A = a(i,j) is totally monotone if for all i{sub 1} < i{sub 2} and j{sub 1} < j{sup 2}, < a(i{sub 1},j{sub 2}) implies a(i{sub 2},j{sub 1})). For large values of k (in particular, for k=(n/2)), this algorithm is significantly faster than the O(k(m+n))-time algorithm for the same problem due to Kravets and Park. An immediate consequence of this result is an O(n{sup 3/2} lg{sup 2}n)-time algorithm for computing the kth nearest neighbor of each vertex of a convex n-gon. In addition to the main result, we also give an O(n lg m)-time algorithm for computing an approximate median in each row of an m {times} n totally monotone array; this approximate median is an entry whose rank in its row lies between (n/4) and (3n/4) {minus} 1. 20 refs., 3 figs.
The Last Total Eclipse of the Millenium
NSDL National Science Digital Library
Ramanujan, Krishna.
On August 11, 1999, a rare total solar eclipse will cast its shadow across the earth. Part of the rarity of this year's eclipse is the fact that the path of totality (the viewing track of the total eclipse) will cover so much inhabited land. First hitting soil in Cornwall, UK, the moon's umbra (complete shadow) will cut a path relatively close to many major cities of Europe, the Middle East, and South Asia, finally ending over India in the Bay of Bengal. Cities that will view the eclipse include London, Paris, Munich, Bucharest, Baghdad, Karachi, and Ahmadabad. Of course, earthbound observers will be dependent upon clear skies to view the event. Statistical calculations of climatological data have helped determine the areas of highest probability for good weather. In addition to the wonderful spectacle, the eclipse also offers researchers unique opportunities to collect data on the sun's corona. Although the umbra will not pass over North America directly, satellite technology affords North Americans the opportunity to view the eclipse via live Webcasts (see above). The ten resources listed provide articles, information, and data in preparation for this last eclipse of the millennium.
Climate Change and Tropical Total Lightning
NASA Technical Reports Server (NTRS)
Albrecht, R.; Petersen, W.; Buechler, D.; Goodman, S.; Blakeslee, R.; Christian, H.
While global warming is regarded as a fact by many in the scientific community, its future impact remains a challenge to be determined and measured. The International Panel on Climate Change (IPCC) assessment report (IPCC, 2007) shows inconclusive answers on global rainfall trends and general agreement on a future drier climate with increased global warming. The relationship between temperature, humidity and convection is not linear and is strongly dependent on regional scale features, such as topography and land cover. Furthermore, the relationship between convective lightning production (thunderstorms) and temperature is even more complicated, being subjected to the cloud dynamics and microphysics. Total lightning (intracloud and cloud-to-ground) monitoring is a relatively new field of observation. Global and tropical total lightning began to be more extensively measured by satellites in the mid 90s. In this scope, the Lightning Imaging Sensor (LIS) onboard of the Tropical Rainfall Measurement Mission (TRMM) has been operational for over 11 years. Here we address total lightning trends observed by LIS from 1998 to 2008 in different temporal (annual and seasonal) and spatial (large and regional) scales. The observed 11-year trends are then associate to different predicted/hypothesized climate change scenarios.
[Prediction of total nitrogen and total phosphorus concentrations in purple soil using hyperspectral data].
Xu, Li-Hua; Xie, De-Ti; Wei, Chao-Fu; Li, Bing
Hyper-spectral remote sensing is one of the effective means for prediction of soil nutrients. Taking Wangjiagou small watershed of Three Gorges Reservoir Area as researching zone, based on the soil physicochemical properties, reflective spectrum analysis and measurement, were built predictive models for total phosphorous and total phosphorus concentrations in purple soil. Meanwhile, 33 soil samples from paddy soil were used to validate the prediction models for soil nutrients in purple soil. Results show that the total correlation coefficients between their predicted values and measured values of total nitrogen and total phosphorus concentration in purple soil are 0.672 and 0.498, respectively. Correlation coefficients obtained from predictive model of purple soil nutrients validated by paddy soil samples are 0.550 and 0.124. Therefore, it is reasonable to use hyper-spectrum method to prediction total nitrogen concentration. But prediction accuracy for total phosphorus concentration in purple soil is relatively poor. The prediction model of soil nutrients in purple soil is not suitable for paddy soil. PMID:23705441
Simultaneous Bilateral Anterior Approach Total Hip Arthroplasty.
Gondusky, Joseph S; Pinkos, Kevin A; Choi, Leera; Patel, Jay J; Barnett, Steven; Gorab, Robert S
Simultaneous bilateral total hip arthroplasty (THA) has been performed successfully, with good outcomes and low complication rates reported. Most published studies on the topic used anterolateral or posterior surgical approaches. The anterior approach is performed under live fluoroscopy with the patient supine, obviating the need for patient repositioning during bilateral surgery. The authors report their experience with simultaneous bilateral anterior approach total hip arthroplasty. The authors retrospectively reviewed data for 75 patients (150 hips). Mean follow-up was 26 months (range, 5-60 months). Mean patient age was 59 years and the majority were American Society of Anesthesiology class 2 (range, 1-3). Mean total surgical time was 144 minutes (72 minutes per hip). Mean blood loss was 565 mL. Mean hospital length of stay was 2.75 days (range, 1-4 days). Ninety-six percent of patients were able to ambulate on postoperative day 1. Sixty-eight percent of patients were discharged to home. Mean Harris Hip Score improved from 50 to 97. All patients noted a return to preoperative level of activity or higher. Complications included 1 atraumatic minimally displaced trochanteric fracture occurring 2 weeks postoperatively, 1 pulmonary embolism on postoperative day 3 treated without sequelae, 1 episode of postoperative atrial fibrillation, and 4 minor local wound complications. No readmission, infection, nerve palsy, dislocation, reoperation, or death occurred. Anterior approach THA has the advantage of a single supine position for bilateral simultaneous surgery and the current study supports its use in appropriate patients. [Orthopedics. 2015; 38(7):e611-e615.]. PMID:26186324
Total Pelvic Exenteration for Gynecologic Malignancies
Diver, Elisabeth J.; Rauh-Hain, J. Alejandro; del Carmen, Marcela G.
Total pelvic exenteration (PE) is a radical operation, involving en bloc resection of pelvic organs, including reproductive structures, bladder, and rectosigmoid. In gynecologic oncology, it is most commonly indicated for the treatment of advanced primary or locally recurrent cancer. Careful patient selection and counseling are of paramount importance when considering someone for PE. Part of the evaluation process includes comprehensive assessment to exclude unresectable or metastatic disease. PE can be curative for carefully selected patients with gynecologic cancers. Major complications can be seen in as many as 50% of patients undergoing PE, underscoring the need to carefully discuss risks and benefits of this procedure with patients considering exenterative surgery. PMID:22720150
Total Syntheses of Kealiinines A-C
Das, Jayanta; Koswatta, Panduka B.; Jones, J. Daniel; Yousufuddin, Muhammed; Lovely, Carl J.
Short total syntheses of the Leucetta-derived alkaloids, kealiinines A-C, have been accomplished using an intramolecular Friedel-Crafts-dehydration sequence of a bis benzylic diol. The precursor diol was obtained through a series of position specific Grignard reactions from 1-methyl-4,5-diiodoimidazole. C2-Azidation and hydrogenation of the azide then provided the reported structures of kealiinines A-C. While the 1H NMR data did not completely match for these materials, the HPLC data were consistent with the assigned structure of these materials. PMID:23215346
Total skin electron irradiation techniques: a review
Milecki, Piotr; Sk¾rska, Ma?gorzata; Fundowicz, Dorota
Total skin electron irradiation (TSEI) has been employed as one of the methods of mycosis fungoides treatment since the mid-twentieth century. In order to improve the effects and limit the complications following radiotherapy, a number of varieties of the TSEI method, frequently differing in the implementation mode have been developed. The paper provides a systematic review of the different varieties of TSEI. The discussed differences concerned especially: (i) technological requirements and geometric conditions, (ii) the alignment of the patient, (iii) the number of treatment fields, and (iv) dose fractionation scheme. PMID:24278046
Total skin electron irradiation techniques: a review.
Piotrowski, Tomasz; Milecki, Piotr; Sk¾rska, Ma?gorzata; Fundowicz, Dorota
Total skin electron irradiation (TSEI) has been employed as one of the methods of mycosis fungoides treatment since the mid-twentieth century. In order to improve the effects and limit the complications following radiotherapy, a number of varieties of the TSEI method, frequently differing in the implementation mode have been developed. The paper provides a systematic review of the different varieties of TSEI. The discussed differences concerned especially: (i) technological requirements and geometric conditions, (ii) the alignment of the patient, (iii) the number of treatment fields, and (iv) dose fractionation scheme. PMID:24278046
Total body nitrogen analysis. [neutron activation analysis
NASA Technical Reports Server (NTRS)
Palmer, H. E.
Studies of two potential in vivo neutron activation methods for determining total and partial body nitrogen in animals and humans are described. A method using the CO-11 in the expired air as a measure of nitrogen content was found to be adequate for small animals such as rats, but inadequate for human measurements due to a slow excretion rate. Studies on the method of measuring the induced N-13 in the body show that with further development, this method should be adequate for measuring muscle mass changes occurring in animals or humans during space flight.
Enantioselective total synthesis of (+)-lyngbyabellin m.
Pirovani, Rodrigo V; Brito, Gilmar A; Barcelos, Rosimeire C; Pilli, Ronaldo A
Lyngbyabellin M is a non-ribosomal peptide synthetase/polyketide synthase derived metabolite isolated from the cyanobacterium M. bouillonii displaying thiazole rings and a distinct chlorinated octanoic acid chain. Its absolute configuration was proposed based on the comparison of its spectroscopic data with those of other representatives of this family of marine natural products, as well as degradation and derivatization studies. Here the first total synthesis of (+)-lyngbyabellin M is described based on the coupling of three key intermediates: two chiral thiazole moieties and an anti hydroxycarboxylic acid prepared stereoselectively via a boron enolate mediated aldol reaction directed by Masamune's chiral auxiliary. PMID:26023838
Infection rates associated with total parenteral nutrition.
Madeo, M; Lowry, L
The use of central venous access devices is increasingly common within healthcare, and such devices carry an associated risk of infection. Additional risk reduction strategies need exploring to reduce avoidable infections. A prospective 12-month audit was performed on the use of 2% chlorhexidine gluconate transparent, antimicrobial dressing to cover the catheter exit site in patients receiving total parenteral nutrition. The results showed a decrease in catheter-related bloodstream infection (CRBSI) from eight cases to zero (P=0.057), making this film dressing a possible useful addition in the goal of zero avoidable CRBSIs within this high risk group of patients. PMID:21958684
Optimizing perioperative management of total joint arthroplasty.
Johnson, Rebecca L; Kopp, Sandra L
Clinical pathways for total joint arthroplasty have been shown to reduce costs and significantly impact perioperative outcomes mainly through reducing provider variability. Effective clinical pathways link evidence to individual practice and balance costs with local experience, outcomes, and access to resources for responsible perioperative management. Common components of clinical pathways with major impact on perioperative outcomes are: 1) implementing pathways designed to include multimodal analgesia with regional anesthesia, 2) use of tranexamic acid to reduce blood loss, and 3) preconditioning followed by participation in early, accelerated rehabilitation programs to prevent postoperative complications related to immobility. PMID:25453667
Enantioselective Total Synthesis of (+)-Lyngbyabellin M
Pirovani, Rodrigo V.; Brito, Gilmar A.; Barcelos, Rosimeire C.; Pilli, Ronaldo A.
Lyngbyabellin M is a non-ribosomal peptide synthetase/polyketide synthase derived metabolite isolated from the cyanobacterium M. bouillonii displaying thiazole rings and a distinct chlorinated octanoic acid chain. Its absolute configuration was proposed based on the comparison of its spectroscopic data with those of other representatives of this family of marine natural products, as well as degradation and derivatization studies. Here the first total synthesis of (+)-lyngbyabellin M is described based on the coupling of three key intermediates: two chiral thiazole moieties and an anti hydroxycarboxylic acid prepared stereoselectively via a boron enolate mediated aldol reaction directed by MasamuneÆs chiral auxiliary. PMID:26023838
Total synthesis of anticoagulant pentasaccharide fondaparinux.
Li, Tiehai; Ye, Hui; Cao, Xuefeng; Wang, Jiajia; Liu, Yonghui; Zhou, Lifei; Liu, Qiang; Wang, Wenjun; Shen, Jie; Zhao, Wei; Wang, Peng
The anticoagulant pentasaccharide fondaparinux was synthesized using an improved and optimized synthetic strategy including a convergent [3+2] coupling approach, orthogonal protecting groups and various glycosyl donors. The new methods of glycosylation were also used for controlling the stereochemical configuration and improving the yield of the glycosylation. In addition, HPLC and NMR methods to monitor the process of total synthesis of fondaparinux were employed. This work provides a comprehensive elaboration for the synthesis and analysis of fondaparinux based on related literature, as well as abundant information for the synthesis of heparin-like oligosaccharides. PMID:24729477
Soft tissue balancing in total shoulder replacement.
Mueller, Maike; Hoy, Gregory
Total shoulder arthroplasty is now capable of recreating near anatomic reproduction of native bony shoulder anatomy, but the function and longevity of anatomic shoulder replacement is dependent on a competent soft tissue envelope and adequate motoring of all musculo-tendinous units about the shoulder. Balancing the soft tissues requires understanding of the anatomy and pathology, as well as technical skills. The advent of reverse shoulder biomechanics has brought with it special requirements of understanding of the soft tissue elements still left in the shoulder despite major rotator cuff deficiency. PMID:24390706
Total synthesis of diterpenoid steenkrotin?a.
Pan, Saiyong; Xuan, Jun; Gao, Beiling; Zhu, An; Ding, Hanfeng
A concise and diastereoselective total synthesis of the diterpenoid (▒)-steenkrotin?A is described for the first time. The strategy mainly features three key ring formations: 1)?a rhodium-catalyzed O?H bond insertion followed by an intramolecular carbonyl-ene reaction to build up the tetrahydrofuran subunit; 2)?sequential SmI2 -mediated Ueno-Stork and ketyl-olefin cyclizations to construct the [5,7] spirobicyclic skeleton; and 3)?an intramolecular aldol condensation/vinylogous retro-aldol/aldol sequence to form the final six-membered ring with inversion of the relative configuration at the C7 position. PMID:25891977
Cholestasis induced by total parenteral nutrition.
Guglielmi, Francesco William; Regano, Nunzia; Mazzuoli, Silvia; Fregnan, Simona; Leogrande, Giuseppina; Guglielmi, Altomarino; Merli, Manuela; Pironi, Loris; Penco, J M Moran; Francavilla, Antonio
Parenteral nutrition is a life-saving treatment for patients who have acute and chronic intestinal failure. Severe cholestasis induced by total parental nutrition (TPN-IC) is characterized by bile duct regeneration, portal inflammation, and fibrosis. Its progression could be very rapid, and in some patients liver cirrhosis may develop in few months. This article describes the definition, incidence, hepatic changes, histopathologic findings, risk factors, pathogenesis, and clinical implications of TPN-IC. The goal is to improve hospital and home management, quality of life, and prognosis of patients requiring parenteral nutrition. PMID:18242499
38 CFR 3.340 - Total and permanent total ratings and unemployability.
Code of Federal Regulations, 2012 CFR
...disability ratings Ś(1) General. Total disability will be considered to exist when there is present any impairment of mind or body which is sufficient to render it impossible for the average person to follow a substantially gainful...
38 CFR 3.340 - Total and permanent total ratings and unemployability.
Code of Federal Regulations, 2014 CFR
...disability ratings Ś(1) General. Total disability will be considered to exist when there is present any impairment of mind or body which is sufficient to render it impossible for the average person to follow a substantially gainful...
38 CFR 3.340 - Total and permanent total ratings and unemployability.
Code of Federal Regulations, 2010 CFR
...disability ratings Ś(1) General. Total disability will be considered to exist when there is present any impairment of mind or body which is sufficient to render it impossible for the average person to follow a substantially gainful...
Positron interactions with water¢total elastic, total inelastic, and elastic differential cross section measurements
Tattersall, Wade [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia) [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Centre for Antimatter-Matter Studies, School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia); Chiari, Luca [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia)] [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia); Machacek, J. R.; Anderson, Emma; Sullivan, James P. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)] [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); White, Ron D. [Centre for Antimatter-Matter Studies, School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia)] [Centre for Antimatter-Matter Studies, School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia); Brunger, M. J. [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia) [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Buckman, Stephen J. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia) [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Garcia, Gustavo [Instituto de F?sica Fundamental, Consejo Superior de Investigationes Cient?ficas (CSIC), Serrano 113-bis, E-28006 Madrid (Spain)] [Instituto de F?sica Fundamental, Consejo Superior de Investigationes Cient?ficas (CSIC), Serrano 113-bis, E-28006 Madrid (Spain); Blanco, Francisco [Departamento de F?sica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, E-28040 Madrid (Spain)] [Departamento de F?sica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, E-28040 Madrid (Spain)
Utilising a high-resolution, trap-based positron beam, we have measured both elastic and inelastic scattering of positrons from water vapour. The measurements comprise differential elastic, total elastic, and total inelastic (not including positronium formation) absolute cross sections. The energy range investigated is from 1 eV to 60 eV. Comparison with theory is made with both R-Matrix and distorted wave calculations, and with our own application of the Independent Atom Model for positron interactions.
Resident Resident Resident Non-Resident Fees* Total Additional Building Fees* Total**
Maxwell, Bruce D.
Non- Non- Resident Resident Resident Non-Resident Fees* Total Additional Building Fees* Total,701.65 11 2,443.10 685.95 3,129.05 2,443.10 6,337.10 63.25 685.95 9,529.40 12 & up 2,665.20 709.75 3,374, 2013 * Schedule of Fees Health/ Information Registration Building SFEP Computer ASMSU Dental SU
Simultaneous determination of total nitrogen and total phosphorus in freshwater samples using persulfate digestion
Masaaki Hosomi; Ryuichi Sudo
The accuracy and precision of total nitrogen (T?N) and total phosphorus (T?P) determinations in freshwater samples by the simultaneous digestion method using an oxidizing reagent solution of NaOH?K2S2O8 were assessed. Detection limits based on the blank test of nitrogen and phosphorus were 0.02 mgN\\/1 and 0.001 mgP\\/1, respectively. This simultaneous digestion method gave not only a high recovery and reproducibility
Periprosthetic Fractures Following Total Knee Arthroplasty
Kim, Nam Ki
Periprosthetic fractures after total knee arthroplasty may occur in any part of the femur, tibia and patella, and the most common pattern involves the supracondylar area of the distal femur. Supracondylar periprosthetic fractures frequently occur above a well-fixed prosthesis, and risk factors include anterior femoral cortical notching and use of the rotational constrained implant. Periprosthetic tibial fractures are frequently associated with loose components and malalignment or malposition of implants. Fractures of the patella are much less common and associated with rheumatoid arthritis, use of steroid, osteonecrosis and malalignment of implants. Most patients with periprosthetic fractures around the knee are the elderly with poor bone quality. There are many difficulties and increased risk of nonunion after treatment because reduction and internal fixation is interfered with by preexisting prosthesis and bone cement. Additionally, previous soft tissue injury is another disadvantageous condition for bone healing. Many authors reported good clinical outcomes after non-operative treatment of undisplaced or minimally displaced periprosthetic fractures; however, open reduction or revision arthroplasty was required in displaced fractures or fractures with unstable prosthesis. Periprosthetic fractures around the knee should be prevented by appropriate technique during total knee arthroplasty. Nevertheless, if a periprosthetic fracture occurs, an appropriate treatment method should be selected considering the stability of the prosthesis, displacement of fracture and bone quality. PMID:25750888
Particle-enhanced total internal reflectance fluorescence«
NASA Astrophysics Data System (ADS)
Chu, Victor P.; Zoha, Steven J.; Davis, Jim; Chance, Suzette
This paper presents work toward a retrofit of an acaTMIV Discrete Clinical Analyzer (E. I. du Pont de Nemours and Company, Wilmington, DE) with a Particle Enhanced Total Internal Reflection Fluorescence technology. The DuPont acaTM line of instruments was designed to perform highly accurate unit dose clinical chemistry assays. Introduction of a Total Reflectance Fluorescence optics into an acaTMIV could provide capability to perform highly sensitive homogeneous immunoassays. Sensitivity and precision depended upon uniform immobilization of immunoglobulins or immunogens, representing examples of specific binding partners, onto an ionomeric material, acting as both solid support and wall material of the disposable reagent units called the `pack'. This study examines the uniformity of antibody coating onto various types of tough and flexible optical polymeric films including those made from the DuPont SurlynTM and NucrelTM polymers. A number of coating processes will also be described. Bioanalytical tools were developed to determine uniformity, quantity, and activity of antibody coated onto the `pack' film, thus allowing for optimization of polymer film type and process of antibody coating.
Total synthesis of (+)-schweinfurthins B and E.
Topczewski, Joseph J; Neighbors, Jeffrey D; Wiemer, David F
The first total synthesis of (+)-schweinfurthin B, a potent and differentially active cytotoxic agent, has been accomplished. Completion of the synthesis required just 16 steps in the longest linear sequence from commercially available vanillin. Key synthetic transformations included a Shi epoxidation and an efficient cascade cyclization initiated by treatment of the resulting epoxide with BF(3).OEt(2). Furthermore, use of a methyl ether as a stable protecting group for benzylic alcohols dramatically increased the efficiency of the overall sequence. The benzylic ether can be removed from this electron-rich aromatic system through oxidation with DDQ that provided the desired aldehyde intermediate in quantitative yield and shortened the synthetic sequence. Introduction of the A-ring diol in the required cis stereochemistry then became viable through a short sequence highlighted by an aldol condensation with benzaldehyde to introduce an olefin as a latent carbonyl group at the C-3 position. This synthesis established for the first time the absolute stereochemistry of the natural product, and provides access to material on a scale that will advance biological studies. The total synthesis of the closely related compound (+)-schweinfurthin E also is reported. PMID:19697910
Total assessment audits (TAA) in Iowa
Haman, W.G.
Traditionally, energy, waste reduction and productivity audits are performed for a manufacturing facility independent of one another. Auditors generally deliver recommendations for improvement based on their specialized expertise (energy, waste reduction, productivity, etc.) without regard to how those recommendations may impact other, sometimes less obvious, subsystems or processes within the facility. The audits are typically performed in isolation from the plant upper management and commonly without adequate knowledge of how inherent interrelated operational constraints may directly or indirectly influence the success of audit recommendations. The Total Assessment Audit (TAA) concept originated from the belief that a manufacturing facility is better served using a holistic approach to problem solving rather than the more conventional isolated approach. The total assessment audit methodology partners the upper management team of a company with a multi-disciplined team of industry-specific specialists to collectively ascertain the core opportunities for improvement in the company and then to formulate a company oriented continuous improvement plan. Productivity, waste reduction, and energy efficiency objectives are seamlessly integrated into a single service delivery with the TAA approach. Nontraditional audit objectives that influence profitability and competitiveness such as business management practices, employee training, human resource issues, etc. are also subject to evaluation in a TAA. The underlying premise of this approach is that the objectives are interrelated and that simultaneous evaluation will province synergistic results. Ultimately, it is believed that the TAA approach can motivate a manufacturer to implement improvements it might not otherwise pursue if it were focused only on singular objectives.
21 CFR 872.3940 - Total temporomandibular joint prosthesis.
Code of Federal Regulations, 2010 CFR
...Total temporomandibular joint prosthesis. 872.3940 Section 872...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices...Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is...
21 CFR 872.3940 - Total temporomandibular joint prosthesis.
Code of Federal Regulations, 2014 CFR
...Total temporomandibular joint prosthesis. 872.3940 Section 872...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices...Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is...
21 CFR 872.3940 - Total temporomandibular joint prosthesis.
Code of Federal Regulations, 2011 CFR
...Total temporomandibular joint prosthesis. 872.3940 Section 872...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices...Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is...
21 CFR 872.3940 - Total temporomandibular joint prosthesis.
Code of Federal Regulations, 2013 CFR
...Total temporomandibular joint prosthesis. 872.3940 Section 872...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices...Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is...
Total and inorganic arsenic in foods of the first Hong Kong total diet study.
Chung, Stephen Wai-cheung; Lam, Chi-ho; Chan, Benny Tsz-pun
Arsenic (As) is a metalloid that occurs in different inorganic and organic forms, which are found in the environment from both natural occurrence and anthropogenic activity. The inorganic forms of As (iAs) are more toxic as compared with the organic As, but so far most of the occurrence data in food collected in the framework of official food control are still reported as total As without differentiating the various As species. In this paper, total As and iAs contents of 600 total diet study (TDS) samples, subdivided into 15 different food groups, were quantified by high-resolution inductively coupled plasma mass spectrometry (HR-ICP/MS) and hydride generation (HG) ICP/MS respectively. The method detection limits for both total As and iAs were 3 ?g As kg(-1). As the samples were prepared for TDS, food items were purchased directly from the market or prepared as for normal consumption, i.e. table ready, in the manner most representative of and consistent with cultural habits in Hong Kong as far as practicable. The highest total As and iAs content were found in 'fish, seafood and their products' and 'vegetables and their products' respectively. Besides, this paper also presents the ratios of iAs and total As content in different ready-to-eat food items. The highest ratio of iAs to total As was found in 'vegetables and their products'. It is likely that iAs in vegetables maintained its status even after cooking. PMID:24350756
The total synthesis of Isodon diterpenes.
Lazarski, Kiel E; Moritz, Benjamin J; Thomson, Regan J
Families of structurally related molecules often provide stimulating targets for organic chemists that are engaged in the development of new methods and strategies for natural product synthesis. While typically focused on specific molecules, these synthetic investigations often lead to generalizable concepts and significant opportunities for learning in a greater sense. Historically well-investigated families of natural products, such as the prostanoids, indole alkaloids, and macrolide antibiotics, provide ample evidence for the enduring value of these collective activities. In this Minireview, we turn our attention to the polycyclic family of diterpenes isolated from the Isodon genus of plants and provide an account of the recent methods and strategies utilized for their total synthesis. PMID:25159338
Total Monte Carlo evaluation for dose calculations.
Sj÷strand, H; Alhassan, E; Conroy, S; Duan, J; Hellesen, C; Pomp, S; ųsterlund, M; Koning, A; Rochman, D
Total Monte Carlo (TMC) is a method to propagate nuclear data (ND) uncertainties in transport codes, by using a large set of ND files, which covers the ND uncertainty. The transport code is run multiple times, each time with a unique ND file, and the result is a distribution of the investigated parameter, e.g. dose, where the width of the distribution is interpreted as the uncertainty due to ND. Until recently, this was computer intensive, but with a new development, fast TMC, more applications are accessible. The aim of this work is to test the fast TMC methodology on a dosimetry application and to propagate the (56)Fe uncertainties on the predictions of the dose outside a proposed 14-MeV neutron facility. The uncertainty was found to be 4.2 %. This can be considered small; however, this cannot be generalised to all dosimetry applications and so ND uncertainties should routinely be included in most dosimetry modelling. PMID:24277871
Total synthesis of the Daphniphyllum alkaloid daphenylline
NASA Astrophysics Data System (ADS)
Lu, Zhaoyong; Li, Yong; Deng, Jun; Li, Ang
The Daphniphyllum alkaloids are a large class of natural products isolated from a genus of evergreen plants widely used in Chinese herbal medicine. They display a remarkable range of biological activities, including anticancer, antioxidant, and vasorelaxation properties as well as elevation of nerve growth factor. Daphenylline is a structurally unique member among the predominately aliphatic Daphniphyllum alkaloids, and contains a tetrasubstituted arene moiety mounted on a sterically compact hexacyclic scaffold. Herein, we describe the first total synthesis of daphenylline. A gold-catalysed 6-exo-dig cyclization reaction and a subsequent intramolecular Michael addition reaction, inspired by Dixon's seminal work, were exploited to construct the bridged 6,6,5-tricyclic motif of the natural product at an early stage, and the aromatic moiety was forged through a photoinduced olefin isomerization/6?-electrocyclization cascade followed by an oxidative aromatization process.
Neck after total laryngectomy: CT study
DiSantis, D.J.; Balfe, D.M.; Hayden, R.E.; Sagel, S.S.; Sessions, D.; Lee, J.K.T.
Computed tomographic scans in 23 patients who had undergone total laryngectomy were analyzed retrospectively to determine normal postoperative appearance and to evaluate the role of CT in assessing recurrent neoplasm. Nine patients without clinical evidence of recurrence illustrated the normal postoperative changes: a round or ovoid neopharynx connecting the base of the tongue with the cervical esophagus and intact fat planes surrounding the neopharynx, neurovascular bundles, and sternocleidomastoid muscles. In the 12 patients with recurrent neoplasm, the CT manifestations included masses involving the internal jugular lymph node chain, tracheostomy site, or paratracheal region. CT supplemented physical examination and indirect mirror examination, providing data regarding presence and extent of recurrent tumor and aiding in planning the mode and scope of therapy.
Changes in total body water during spaceflight
NASA Technical Reports Server (NTRS)
Leach, Carolyn S.; Inners, L. D.; Charles, John B.
Total body water (TBW) changes occurring in humans as a consequence of prolonged exposure to microgravity were measured in five male crewmembers of Space Shuttle missions STS-61C and STS-26. It was found that the inflight mean TBW values were significantly different from the preflight and postflight values, while the preflight TBW values were not significantly different from the postflight values. It was also found that individuals may differ in the rate at which they respond to weightlessness. Of the three crewmen who reported experiencing no symptoms of space motion sickness (SMS), two had not exhibited a decrease of TBW at the time of measurements (24 hrs after launch), while the two crewmen who reported SMS of intermediate severity showed a decrease of several kg by 24 hrs, suggesting that dehydration might be an important factor affecting the rate of TBW decrease.
Total synthesis of zyzzyanones A-D.
Nadkarni, Dwayaja H; Murugesan, Srinivasan; Velu, Sadanandan E
Zyzzyanones A-D is a group of biologically active marine alkaloids isolated from Australian marine sponge Zyzzya fuliginosa. They contain a unique bispyrroloquinone ring system as the core structure. The first total synthesis of all four zyzzyanones is described here. The synthesis of these alkaloids started from a previously known 6-benzylamino indole-4,7-quinone derivative and involves 6-7 steps. The key step in the synthesis involves the construction of a pyrrole ring in one step using a Mn(OAc)3 mediated oxidative free radical cyclization reaction of a 6-benzylamino indole-4,7-quinone derivative with 4-benzyloxyphenyl acetaldehyde diethyl acetal in CH3CN. PMID:23956468
Total quality management issues in managed care.
McLaughlin, C P; Kaluzny, A D
The implementation of total quality management (TQM) in health care has gone on in parallel with the growth of managed care. What is the interaction between the two? Key issues are the ascendance of cost control over quality in many areas, erosion of employee commitment and loyalty, and a short-run orientation. Associated with this is an emphasis on organizational learning rather than learning by autonomous professionals. Both TQM and managed care acknowledge the dynamic nature of clinical processes and the ability and responsibility of both institutions and clinicians to improve their processes. Both are consistent with efforts to identify and implement best practices. However, these similarities should not mask fundamental differences. Continuous improvement must shift its focus from avoiding unnecessary variation to facilitating rapid organizational learning and institutionalizing mass customization into the delivery of health services. PMID:9327355
Total quality management in clinical virology laboratories.
Tibbets, M W; Gomez, R; Kannangai, R; Sridharan, G
The diagnostic laboratories in India are progressively promoting higher standards and are moving towards accreditation and international acceptance. Hence, the concept of "Quality" will need to be understood and implemented. Total quality management (TQM) in a laboratory is an integrated program involving all laboratory staff and management. TQM is a framework to operate and it is aiming for integration, consistency, increase in efficiency and a continuous drive for improvement. A well structured clinical virology service will include serology setup, cell culture facility and capacity for molecular diagnosis. The quality of results from the laboratory is significantly influenced by many pre-analytical and post-analytical factors which needed attention. The end goal of the TQM should be to provide the best care possible for the patient. PMID:17185843
Total hip arthroplasty after rotational acetabular osteotomy.
Ito, Hideya; Takatori, Yoshio; Moro, Toru; Oshima, Hirofumi; Oka, Hiroyuki; Tanaka, Sakae
In this study, we aimed to determine whether the outcomes of total hip arthroplasty (THA) after rotational acetabular osteotomy (RAO) are equal to those of primary THA, and to elucidate the characteristics of THA after RAO. The clinical and radiographic findings of THA after RAO (44 hips), with minimum 24 months of follow-up, were compared with a matched control group of 58 hips without prior RAO. We found that the outcomes in terms of functional scores and complication rates did not differ between THA after RAO and THA without previous pelvic osteotomy, indicating that the results of THA after RAO are equivalent to those of primary THA. Although THA after RAO requires technical considerations, similar clinical outcomes to primary THA can be expected. PMID:25456635
Enantioselective total syntheses of acylfulvene, irofulven, and the agelastatins
Siegel, Dustin S. (Dustin Scott), 1980-
I. Enantioselective Total Synthesis of (-)-Acylfulvene, and (-)-Irofulven We report the enantioselective total synthesis of (-)-acylfulvene and (-)-irofulven, which features metathesis reactions for the rapid assembly of ...
Reduced total antioxidant status in postterm pregnancies
Kaya, S; Keskin, H L; Kaya, B; Ustuner, I; Avsar, A F
Background: The placenta is the major source of oxidative stress in normal human pregnancy. The placental tissue is typically functional in postterm pregnancies. We hypothesized that such pregnancies experience deteriorating oxidative balance and increasing oxidative stress. In this case-control study, our aim was to investigate the oxidative status in postterm pregnancies comparing with term by using total antioxidant status (TAS) measurement. Methods: Fifty pregnant women who were in their 41st gestational week (GW) and whose labor had not yet started were selected for the study group. Fifty subjects whose spontaneous labor onset and who delivered before their 41st GW were included for control group. Venous blood samples were obtained from each participant before the onset of labor. A premixed reagent was used to obtain serum TAS measurements from the blood samples. The Mann-Whitney test was used to compare the groups. Results: Age, gravity, and parity of the subjects were similar between the groups (p> 0.05). Body mass index (BMI) were statistically higher in postterm group (p =0.011). The median (interquartile range) TAS level was lower in the pregnancies beyond 41 weeks than term pregnancies [1.69 (0.12) mM vs 1.75 (0.20) mM, (p< 0.05)]. Conclusions: A lower total antioxidant status in past days pregnancy suggests an association with decreased oxidative status compared to term. It can be speculated that pregnancies beyond 41 weeks are associated with decreased oxidative stress and this may be play a role in the etiology of the prolonged pregnancy. PMID:23935345
A visibility and total suspended dust relationship
NASA Astrophysics Data System (ADS)
Baddock, M. C.; Strong, C. L.; Leys, J. F.; Heidenreich, S. K.; Tews, E. K.; McTainsh, G. H.
This study reports findings on observed visibility reductions and associated concentrations of mineral dust from a detailed Australian case study. An understanding of the relationship between visibility and dust concentration is of considerable utility for wind erosion and aeolian dust research because it allows visibility data, which are available from thousands of weather observation stations worldwide, to be converted into dust concentrations. Until now, this application of visibility data for wind erosion/dust studies has been constrained by the scarcity of direct measurements of co-incident dust concentration and visibility measurements. While dust concentrations are available from high volume air samplers, these time-averaged data cannot be directly correlated with instantaneous visibility records from meteorological observations. This study presents a new method for deriving instantaneous values of total suspended dust from time averaged (filter-based) samples, through reference to high resolution PM10 data. The development and testing of the model is presented here as well as a discussion of the derived expression in relation to other visibility-dust concentration predictive curves. The current study is significant because the visibility-dust concentration relationship produced is based on visibility observations made 10-100Ākm from the dust sources. This distance from source makes the derived relationship appropriate for a greater number of visibility recording stations than widely-used previous relationships based on observations made directly at eroding sources. Testing of the new formula performance against observed total suspended dust concentrations demonstrates that the model predicts dust concentration relatively well (r2Ā=Ā0.6) from visibility. When considered alongside previous studies, the new relationship fits into the continuum of visibility-dust concentration outcomes existing for increasing distance-from-source. This highlights the important influence that distance to source has on the visibility-dust concentration relationship.
Total Percutaneous Aortic Repair: Midterm Outcomes
Bent, Clare L., E-mail: firstname.lastname@example.com; Fotiadis, Nikolas; Renfrew, Ian [Barts and The London NHS Trust, Department of Diagnostic Imaging (United Kingdom); Walsh, Michael; Brohi, Karim [Barts and The London NHS Trust, Department of Vascular Surgery and Trauma Surgery (United Kingdom); Kyriakides, Constantinos [Barts and The London NHS Trust, Department of Vascular Surgery and Queen Mary's School of Medicine and Dentistry (United Kingdom); Matson, Matthew, E-mail: firstname.lastname@example.com [Barts and The London NHS Trust, Department of Diagnostic Imaging (United Kingdom)
The purpose of this study was to examine the immediate and midterm outcomes of percutaneous endovascular repair of thoracic and abdominal aortic pathology. Between December 2003 and June 2005, 21 patients (mean age: 60.4 {+-} 17.1 years; 15 males, 6 females) underwent endovascular stent-graft insertion for thoracic (n = 13) or abdominal aortic (n = 8) pathology. Preprocedural computed tomographic angiography (CTA) was performed to assess the suitability of aorto-iliac and common femoral artery (CFA) anatomy, including the degree of CFA calcification, for total percutaneous aortic stent-graft repair. Percutaneous access was used for the introduction of 18- to 26-Fr delivery devices. A 'preclose' closure technique using two Perclose suture devices (Perclose A-T; Abbott Vascular) was used in all cases. Data were prospectively collected. Each CFA puncture site was assessed via clinical examination and CTA at 1, 6, and 12 months, followed by annual review thereafter. Minimum follow-up was 36 months. Outcome measures evaluated were rates of technical success, conversion to open surgical repair, complications, and late incidence of arterial stenosis at the site of Perclose suture deployment. A total of 58 Perclose devices were used to close 29 femoral arteriotomies. Outer diameters of stent-graft delivery devices used were 18 Fr (n = 5), 20 Fr (n = 3), 22 Fr (n = 4), 24 Fr (n = 15), and 26 Fr (n = 2). Percutaneous closure was successful in 96.6% (28/29) of arteriotomies. Conversion to surgical repair was required at one access site (3.4%). Mean follow-up was 50 {+-} 8 months. No late complications were observed. By CT criteria, no patient developed a >50% reduction in CFA caliber at the site of Perclose deployment during the study period. In conclusion, percutaneous aortic stent-graft insertion can be safely performed, with a low risk of both immediate and midterm access-related complications.
Coronal Dynamics at Recent Total Solar Eclipses
NASA Astrophysics Data System (ADS)
Pasachoff, J. M.; Lu, M.; Davis, A. B.; Demianski, M.; Rusin, V.; Saniga, M.; Seaton, D. B.; Lucas, R.; Babcock, B. A.; Dantowitz, R.; Gaintatzis, P.; Seeger, C. H.; Malamut, C.; Steele, A.
Our composite images of the solar corona based on extensive imaging at the total solar eclipses of 2010 (Easter Island), 2012 (Australia), and 2013 (Gabon) reveal several coronal mass ejections and other changes in coronal streamers and in polar plumes. Our resultant spatial resolution is finer than that available in imaging from spacecraft, including that from SOHO/LASCO or STEREO. We trace the eruptions back to their footpoints on the sun using imaging from SDO and SWAP, and follow them upwards through the corona, measuring velocities. The high-resolution computer compositing by Miloslav Druckm³ller and Hana Druckm³llerovß (2010 and 2013) and Pavlos Gaintatzis (2012) allows comparison of our images with those taken at intervals of minutes or hours along the totality path. Williams College's 2013 eclipse expedition was supported in part by grant 9327-13 from National Geographic Society/Committee for Research and Exploration. Our work on the 2012 eclipse is supported in part by grant AGS-1047726 from Solar Terrestrial Research/NSF AGS. V.R. and M.S. were partially supported by the VEGA grant agency project 2/0098/10 and 2/0003/13 (Slovak Academy of Sciences) and Grant 0139-12 from NG/CRE, and Hana Druckm³llerovß by grant 205/09/1469 of the Czech Science Foundation. M.L. was supported by Sigma Xi. C.M. was a Keck Northeast Astronomy Consortium Summer Fellow, supported at Williams College by REU/NSF grant AST-1005024. Partial support was provided by U.S. Department of Defense's ASSURE program. J.M.P. thanks Caltech's Planetary Sciences Department for hospitality. Support for D.B.S. and SWAP came from PRODEX grant C90345 managed by ESA in collaboration with the Belgian Federal Science Policy Office (BELSPO) in support of the PROBA2/SWAP mission, and from the EC's Seventh Framework Programme (FP7/2007-2013) under grant 218816 (SOTERIA project, www.soteria-space.eu). SWAP is a project of the Centre Spatial de LiĶge and the Royal Observatory of Belgium funded by BELSPO.
Soil Test P vs. Total P in Wisconsin Soils
Balser, Teri C.
Science University of Wisconsin-Madison #12;Introduction Ę Soil test P is often measured Ę LittleSoil Test P vs. Total P in Wisconsin Soils Larry G. Bundy & Laura W. Good Department of Soil information is available on total P content of soils Ę Why do we care about total P now? Ł Soil total P
38 CFR 8.18 - Total disability-speech.
Code of Federal Regulations, 2010 CFR
...2010-07-01 2010-07-01 false Total disability-speech. 8.18 Section 8.18 Pensions, Bonuses...Total Disability ¦ 8.18 Total disabilityŚspeech. The organic loss of speech shall be deemed to be total disability under...
Process optimized minimally invasive total hip replacement
Gebel, Philipp; Oszwald, Markus; Ishaque, Bernd; Ahmed, Gaffar; Blessing, Recha; Thorey, Fritz; Ottersbach, Andreas
The purpose of this study was to analyse a new concept of using the the minimally invasive direct anterior approach (DAA) in total hip replacement (THR) in combination with the leg positioner (Rotex- Table) and a modified retractor system (Condor). We evaluated retrospectively the first 100 primary THR operated with the new concept between 2009 and 2010, regarding operation data, radiological and clinical outcome (HOOS). All surgeries were perfomed in a standardized operation technique including navigation. The average age of the patients was 68 years (37 to 92 years), with a mean BMI of 26.5 (17 to 43). The mean time of surgery was 80 min. (55 to 130 min). The blood loss showed an average of 511.5 mL (200 to 1000 mL). No intra-operative complications occurred. The postoperative complication rate was 6%. The HOOS increased from 43 points pre-operatively to 90 (max 100 points) 3 months after surgery. The radiological analysis showed an average cup inclination of 43░ and a leg length discrepancy in a range of +/? 5 mm in 99%. The presented technique led to excellent clinic results, showed low complication rates and allowed correct implant positions although manpower was saved. PMID:22577504
Total parenteral nutrition in diabetic rats
Norcross, E.D.; Stein, T.P.
Parenteral Nutrition with hypertonic glucose is frequently given to diabetic patients. Large amounts of insulin can be required. The purpose of this investigation was to develop a totally parenterally nourished diabetic rat model. 200 g Female Sprague Dawley rats were made diabetic by i.v. injection of streptozotocin (50 mg/kg). Rats were then allowed to recover for at least 1 week before undergoing surgical insertion of a central venous catheter for parenteral feeding. TPN was begun 3 days after surgery. Prior to this they were allowed unlimited access to food and water. Control (non-streptozotocin treated) rats were run at the same time. Protein turnover was investigated by using /sup 15/N glycine. Preliminary results: diabetic rats given mostly fat as a calorie source survived well in the absence of exogenous insulin whereas those that were given glucose only as their non-protein calorie source showed poor survival even with exogenous insulin. N balance and protein turnover in the lipid treated diabetic rats were comparable to the non-diabetic control rats.
Total residual chlorine as a regulatory tool
Mattice, J.S.; Tsai, S.C.
Inherent in the choice of total residual chlorine (TRC) as a basis for establishing water quality criteria or effluent guidelines for chlorine are assumptions that components of TRC are roughly equivalent in toxicity to aquatic species and that the toxicities of these components are additive. Most of the studies of this assumption involved comparisons of mixtures of residual chlorine components and thus led to conflicting conclusions. In addition, studies designed to avoid the mixture problem omitted one or more of the most likely products of chlorination from the comparison(s). On the other hand, the assumption of additive toxicity of residual chlorine species has largely been ignored. In view of the continuing controversy that focused on the levels of residual chlorine which can be discharged without deleterious impact on receiving waters, it is important that these assumptions be evaluated comprehensively. New data on the toxicities to the mosquitofish, Gambusia affinis, of inorganic monochloramine, inorganic dichloramine, a mixture of these two compounds, and two mixtures with free chlorine are reported. These and other data on the toxicity of residual chlorine species to mosquitofish are then used to examine the questions of toxicity equivalence and additivity of species of residual chlorine. (ERB)
Effect of total laryngectomy on esophageal motility
Hanks, J.B.; Fisher, S.R.; Meyers, W.C.; Christian, K.C.; Postlethwait, R.W.; Jones, R.S.
Total laryngectomy for cancer can result in dysphagia and altered esophageal motility. Manometric changes in the upper esophageal sphincter (UES), and in proximal and distal esophageal function have been reported. However, most studies have failed to take into account radiation therapy and appropriate controls. We selected ten male patients (54.3 +/- 1.9 yr) for longitudinal manometric evaluation prior to laryngectomy then at two weeks and again six months later. No patient received preoperative radiation therapy, had a previous history of esophageal surgery, or developed a postoperative wound infection or fistula. Seven of ten patients had positive nodes and received 6,000-6,600 rads postoperative radiation therapy. Preoperatively 4 of 10 patients complained of dysphagia which did not significantly change following surgery and radiation. Two of three patients who did not complain of dysphagia preoperatively and received radiation postoperatively developed dysphagia. No patient without dysphagia preoperatively who received no radiation therapy developed symptoms. Our studies show that laryngectomy causes alterations in the UES resting and peak pressures but not in the proximal or distal esophagus, or the lower esophageal sphincter. These data also imply radiation therapy may be associated with progressive alterations in motility and symptomatology. Further study regarding the effects of radiation on esophageal motility and function are urged.
CMB Anisotropies: Total Angular Momentum Method
Wayne Hu; Martin White
A total angular momentum representation simplifies the radiation transport problem for temperature and polarization anisotropy in the CMB. Scattering terms couple only the quadrupole moments of the distributions and each moment corresponds directly to the observable angular pattern on the sky. We develop and employ these techniques to study the general properties of anisotropy generation from scalar, vector and tensor perturbations to the metric and the matter, both in the cosmological fluids and from any seed perturbations (e.g. defects) that may be present. The simpler, more transparent form and derivation of the Boltzmann equations brings out the geometric and model-independent aspects of temperature and polarization anisotropy formation. Large angle scalar polarization provides a robust means to distinguish between isocurvature and adiabatic models for structure formation in principle. Vector modes have the unique property that the CMB polarization is dominated by magnetic type parity at small angles (a factor of 6 in power compared with 0 for the scalars and 8/13 for the tensors) and hence potentially distinguishable independent of the model for the seed. The tensor modes produce a different sign from the scalars and vectors for the temperature-polarization correlations at large angles. We explore conditions under which one perturbation type may dominate over the others including a detailed treatment of the photon-baryon fluid before recombination.
Total quality management in blood transfusion.
Smit-Sibinga, C T
Quality management is an ongoing development resulting in consistency products and services and ever increasing customer satisfaction. The ultimum is Total Quality Management. Quality systems and quality management in transfusion medicine have gained considerable attention since the outbreak of the AIDS epidemic. Where product orientation has long been applied through quality control, Good Manufacturing Practice (GMP) principles were introduced, shifting the developments in the direction of process orientation. Globally, and particularly in the more industrialised world people and system orientation has come along with the introduction of the ISO9001 concept. Harmonisation and a degree of uniformity are needed to implement a universally applicable Quality System and related Quality Management. Where the American Association of Blood Banks (AABB) is the professional organisation with the most extensive experience in quality systems in blood transfusion, the European Union and the Council of Europe now are in the process to design a quality system and management applicable to a larger variety of countries, based on a hybrid of current GMP and ISO9001 principles. The International Federation of Red Cross and Red Crescent Societies has developed a more universally to implement Quality Manual, with a pilot project in Honduras. It is recommendable to harmonise the various designs and bring the approaches under one common denominator. PMID:10938970
Design of next generation total disk replacements.
van den Broek, Peter R; Huyghe, Jacques M; Wilson, Wouter; Ito, Keita
To improve the treatments for low back pain, new designs of total disk replacement have been proposed. The question is how well these designs can act as a functional replacement of the intervertebral disk. Four finite element models were made, for four different design concepts, to determine how well they can mimic the physiological intervertebral disk mechanical function. The four designs were a homogenous elastomer, a multi-stiffness elastomer, an elastomer with fiber jacket, and a hydrogel with fiber jacket. The best material properties of the four models were determined by optimizing the model behavior to match the behavior of the intervertebral disk in flexion-extension, axial rotation, and lateral bending. It was shown that neither a homogeneous elastomer nor a multi-stiffness elastomer could mimic the non-linear behavior within the physiological range of motion. Including a fiber jacket around an elastomer allowed for physiological motion in all degrees of freedom. Replacing the elastomer by a hydrogel yielded similar good behavior. Mimicking the non-linear behavior of the intervertebral disk, in the physiological range of motion is essential in maintaining and restoring spinal motion and in protecting surrounding tissues like the facet joints or adjacent segments. This was accomplished with designs mimicking the function of the annulus fibrosus. PMID:22035640
Total avulsion of mandible in maxillofacial trauma
Passi, Deepak; Ram, Hari; Singh, Geeta; Malkunje, Laxman
Mandibular trauma are a frequent injury of maxillofacial skeleton due to the mandible's prominence and relative lack of support. Maxillofacial injuries can be complex and can involve the skin and soft-tissues as well as bones resulting in fractures. Although, several cases of severe crush injury of the lower jaw have already been presented but total avulsion of mandible has rarely been reported. As with any facial fracture, consideration must be given for the need of emergency treatment to secure the airway or to obtain hemostasis if necessary before initiating definitive treatment. We presents a case report of completely avulsed mandible along with soft-tissue of midface region in pediatric patient following trauma, which was attempted to manage or repaired by successful microvascular surgical technique. Unfortunately, we lost the patient in next postoperative day due to cardiac complication. Avulsion of the lower jaw may further complicate the obstructive nature of the upper airway. Multi-specialty involvement in their management may be needed for management of such type of avulsion injury. PMID:24987613
Capillary electrophoresis for total glycosaminoglycan analysis.
Ucakturk, Ebru; Cai, Chao; Li, Lingyun; Li, Guoyun; Zhang, Fuming; Linhardt, Robert J
A capillary zone electrophoresis-laser-induced fluorescence detection (CZE-LIF) method was developed for the simultaneous analysis of disaccharides derived from heparan sulfate, chondroitin sulfate/dermatan sulfate, hyaluronan, and keratan sulfate. Glycosaminoglycans (GAGs) were first depolymerized with the mixture of GAG lyases (heparinase I, II, III and chondroitinase ABC and chondroitinase AC II) and GAG endohydrolase (keratinase II) and the resulting disaccharides were derivatized by reductive amination with 2-aminoacridone. Nineteen fluorescently labeled disaccharides were separated using 50 mM phosphate buffer (pH 3.3) under reversed polarity at 25 kV. Using these conditions, all the disaccharides examined were baseline separated in less then 25 min. This CZE-LIF method gave good reproducibility for both migration time (?1.03% for intraday and ?4.4% for interday) and the peak area values (?5.6% for intra- and ?8.69% for interday). This CZE-LIF method was used for profiling and quantification of GAG derivative disaccharides in bovine cornea. The results show that the current CZE-LIF method offers fast, simple, sensitive, reproducible determination of disaccharides derived from total GAGs in a single run. PMID:24817364
Total ankle replacement for posttraumatic arthritis.
Weme, Rebecca A Nieuwe; van Solinge, Guido; N Doornberg, Job; Sierevelt, Inger; Haverkamp, Daniļl; Doets, H Cornelis
Background and purpose - Most studies on total ankle replacement (TAR) have used a case mix of patients. We evaluated the outcome of TAR performed for end-stage arthritis either because of fracture or ligamentous injury. Patients and methods - We prospectively followed 88 consecutive patients (50 postfracture ankles and 40 ankles with instability arthritis (2 bilateral)) who underwent TAR between 2001 and 2009. Mean follow-up for both groups was 5 years. Results - Preoperative varus deformity of 10░ or more was present in 23 ankles in the instability group. At 6 years, survival with revision or salvage fusion as an endpoint was 87% (95% CI: 74-99) in the postfracture group and 79% (95% CI: 63-94) in the instability group. Progressive periprosthetic osteolysis was seen in 23 ankles, and required salvage fusion in 6. The number of reoperations was similar in both groups. Clinical outcome, as assessed with 2 ankle scores and 2 questionnaires, showed good results and was similar at the latest follow-up. Interpretation - The outcome was similar in the postfracture and instability groups and also similar to that reported in series including a case mix of patients. In contrast to earlier reports, preoperative frontal plane deformity in this series was not identified as a risk factor for failure. PMID:25772269
Constrained Implants in Total Knee Replacement.
Touzopoulos, Panagiotis; Drosos, Georgios I; Ververidis, Athanasios; Kazakos, Konstantinos
Total knee replacement (TKR) is a successful procedure for pain relief and functional restoration in patients with advanced osteoarthritis. The number of TKRs is increasing, and this has led to an increase in revision surgeries. The key to long-term success in both primary and revision TKR is stability, as well as adequate and stable fixation between components and underlying bone. In the vast majority of primary TKRs and in some revision cases, a posterior cruciate retaining or a posterior cruciate substituting device can be used. In some primary cases with severe deformity or ligamentous instability and in most of the revision cases, a more constrained implant is required. The purpose of this paper is to review the literature concerning the use of condylar constrained knee (CCK) and rotating hinge (RH) implants in primary and revision cases focusing on the indications and results. According to this review, although excellent and very good results have been reported, there are limitations of the existing literature concerning the indications for the use of constrained implants, the absence of long-term results, and the limited comparative studies. PMID:26055025
Total and inorganic arsenic in Iranian rice.
Cano-Lamadrid, Marina; Munera-Picazo, Sandra; Burl¾, Francisco; Hojjati, Mohammad; Carbonell-Barrachina, ┴ngel A
It is well known that arsenic (As) exposure, particularly to inorganic species (i-As), has adverse effects on humans. Nowadays, the European Union (EU) has still not regulated the maximum residue limit of As in commercial samples of rice and rice-based products, although it is actively working on the topic. The European Food Safety Authority (EFSA) is collecting data on total arsenic (t-As) and i-As from different rice-producing regions not only from EU countries but also from other parts of the world to finally set up this maximum threshold. As Iran is a rice-producing country, the aim of this work was to evaluate the contents of t-As and i-As in 15 samples of Iranian white, nonorganic, and aromatic rice collected from the most important rice-producing regions of the country. The means of t-As and i-As were 120 and 82Ā?g/kg, respectively. The experimental i-As mean in Iranian rice was below the Chinese standard for the i-As in rice, 150Ā?g/kg, and the Food and Agriculture Organization of the United Nations (FAO) limit, 200Ā?g/kg. Therefore, Iranian rice seems to have reasonable low i-As content and it is safe to be marketed in any market, including China and the EU. PMID:25817563
AIRS total precipitable water over high latitudes
NASA Astrophysics Data System (ADS)
Ye, H.; Fetzer, E. J.; Bromwich, D. H.; Fishbein, E.; Olsen, E. T.; Granger, S.; Lee, S.; Lambrigtsen, B.; Chen, L.
Given the importance of atmospheric conditions over the Arctic and Antarctica to the global climate system, hydrological cycles, and cryopspheric dynamics, and the poor coverage of traditional data over these region, AIRS data will play a significant role in filling the information gaps. In this study, we examine the quality of AIRS total atmospheric precipitable water (PWV) and explore its potential applications over the Antarctica and Arctic. For Antarctica, both Level II matching files and Level III gridded products of AIRS are compared with radiosonde records at Dome C and ECMWF's analysis products during December 10, 2003 to January 26, 2004. Results will testify to the quality of AIRS moisture data over glacial surfaces. For the Arctic region, AIRS level III data are used to compare with AMSR-E data and ECMWF analysis product during September of 2004. Results will reveal the quality of AIRS data over high-latitude water, sea ice, and land surfaces. The potential of AIRS data to improve model simulation will be discussed.
Total Operators and Inhomogeneous Proper Values Equations
Jose G. Vargas
Kaehler's two-sided angular momentum operator, K + 1, is neither vector-valued nor bivector-valued. It is total in the sense that it involves terms for all three dimensions. Constant idempotents that are "proper functions" of K+1's components are not proper functions of K+1. They rather satisfy "inhomogeneous proper-value equations", i.e. of the form (K + 1)U = {\\mu}U + {\\pi}, where {\\pi} is a scalar. We consider an equation of that type with K+1 replaced with operators T that comprise K + 1 as a factor, but also containing factors for both space and spacetime translations. We study the action of those T's on linear combinations of constant idempotents, so that only the algebraic (spin) part of K +1 has to be considered. {\\pi} is now, in general, a non-scalar member of a Kaehler algebra. We develop the system of equations to be satisfied by the combinations of those idempotents for which {\\pi} becomes a scalar. We solve for its solutions with {\\mu} = 0, which actually also makes {\\pi} = 0: The solutions with {\\mu} = {\\pi} = 0 all have three constituent parts, 36 of them being different in the ensemble of all such solutions. That set of different constituents is structured in such a way that we might as well be speaking of an algebraic representation of quarks. In this paper, however, we refrain from pursuing this identification in order to emphasize the purely mathematical nature of the argument.
The (Almost) Unseen Total Eclipse of 1831
NASA Astrophysics Data System (ADS)
Bartky, Ian R.
The total eclipse of August 1831 began at sunrise in Australia, swept across the western South Pacific Ocean, and ended at sunset in the central South Pacific. As a result of the eclipse's path over mostly uninhabited ocean, the region's sparse European (British) population, and near-useless local predictions of the event at Hobart and Sydney in almanacs sold to the general public, almost no one witnessed its passage. In an attempt to document the eclipse, journals of naive observers - those having no access to a prediction - were examined. Thus far, the sole record is in the Pitcairn Island Register Book. Considering the Pitcairners' extreme isolation and the rather modest partial eclipse that occurred there, the entry is a surprising one; however, it can be explained in terms of events associated with their initial removal to Tahiti in March 1831 followed by their return home in June. Further, an authoritative means to identify any issues associated with eclipse predictions compiled for private-sector almanacs came in 1833 when sweeping changes in the British Nautical Almanac's section on eclipses were instituted.
Acetabular blood flow during total hip arthroplasty
ElMaraghy, Amr W.; Schemitsch, Emil H.; Waddell, James P.
Objective To determine the immediate effect of reaming and insertion of the acetabular component with and without cement on periacetabular blood flow during primary total hip arthroplasty (THA). Design A clinical experimental study. Setting A tertiary referral and teaching hospital in Toronto. Patients Sixteen patients (9 men, 7 women) ranging in age from 30 to 78 years and suffering from arthritis. Intervention Elective primary THA with a cemented (8 patients) and noncemented (8 patients) acetabular component. All procedures were done by a single surgeon who used a posterior approach. Main outcome measure Acetabular bone blood-flow measurements made with a laser Doppler flowmeter before reaming, after reaming and after insertion of the acetabular prosthesis. Results Acetabular blood flow after prosthesis insertion was decreased by 52% in the noncemented group (p < 0.001) and 59% in the cemented group (p < 0.001) compared with baseline (prereaming) values. Conclusion The significance of these changes in periacetabular bone blood flow during THA may relate to the extent of bony ingrowth, periprosthetic remodelling and ultimately the incidence of implant failure because of aseptic loosening. PMID:10851413
Total Artificial Heart and Physical Therapy Management
Nicholson, Clare
Purpose: To describe the total artificial heart (TAH) device as a bridge to heart transplantation (BTT), and related physical therapy management, while comparisons to left ventricular assist devices (LVAD) are made. Summary: The SynCardia CardioWest Temporary TAH System is the only TAH approved by the Food and Drug Administration (FDA), Health Canada and Consultants Europe (CE) for BTT. CardioWest implantation involves cardiectomy thus avoiding pulmonary hypertension, right heart failure, inotropic or anti-arrhythmic agents, myocardial and valve related problems. CardioWest has a fixed beat rate and cardiac output is dependent upon venous return and preload. Both TAH and LVADs are adaptive with exercise, increasing cardiac output during activities, allowing for conditioning to occur peripherally. Left ventricular assist devices have portable drivers permitting discharge home, while the CardioWest's large driver console necessitates inpatient therapy. Exercise progression, positioning, and monitoring of exercise intolerance are similar with LVAD and TAH. Ventricular fill volumes in TAH dictate cardiac output and require close attention. Cardiectomy in TAH prevents electrocardiography, telemetry, and native pulse rate monitoring. Conclusion: While mechanical differences exist between TAH and LVAD, physical therapists can provide evidence-based treatment for patients with TAH using previously established guidelines for patients with heart failure and mechanical circulatory support. PMID:20520759
[Total quality management in laboratory medicine].
Vogt, W
The German Public Health will be continuously challenged in the future. It has to be assumed that modified managed care will not only take place sporadically. Thus, quality aspects of services gain more and more significance. Only suppliers will be successful who can offer services of highest quality at lowest prices. Quality in a comprehensive sense has to be substantiated in the near future. It is recommended to apply industry proven models also in public health service. Medical laboratories can be pioneers in this field as they have been already in the past. All previously proposed procedures can not describe quality of results comprehensively. They are based to a high degree on external control. Total quality management, however, represents a comprehensive approach. Principles are zero-defect approach, customer orientation and system management. Quality is given in the sense of TQM if the customer is permanently satisfied with the service of the supplier. In such a way, the customer defines quality of service. A customer is everyone who receives products or services. TQM overcomes the drawbacks of quality management systems, which are strongly formal and oriented by external control, as accreditation (EN 45,000) or certification (ISO 9000). Competition between hospitals is a declared goal of German health politics because usually quality is increased and cost decreased as a consequence. Competition means also comparison of services. TQM emphasizes benchmarking especially among the best suppliers. PMID:10028601
Total scalp irradiation using helical tomotherapy
Orton, Nigel [Department of Human Oncology, University of Wisconsin, Madison, WI (United States)]. E-mail: email@example.com; Jaradat, Hazim [Department of Human Oncology, University of Wisconsin, Madison, WI (United States); Welsh, James [Department of Human Oncology, University of Wisconsin, Madison, WI (United States); Tome, Wolfgang [Department of Human Oncology, University of Wisconsin, Madison, WI (United States); Department of Medical Physics, University of Wisconsin, Madison, WI (United States)
Homogeneous irradiation of the scalp poses technical and dosimetric challenges due to the extensive, superficial, curved treatment volume. Conventional treatments on a linear accelerator use multiple matched electron fields or a combination of electron and photon fields. Problems with these techniques include dose heterogeneity in the target due to varying source-to-skin distance (SSD) and angle of beam incidence, significant dose to the brain, and the potential for overdose or underdose at match lines between the fields. Linac-based intensity-modulated radiation therapy (IMRT) plans have similar problems. This work presents treatment plans for total scalp irradiation on a helical tomotherapy machine. Helical tomotherapy is well-suited for scalp irradiation because it has the ability to deliver beamlets that are tangential to the scalp at all points. Helical tomotherapy also avoids problems associated with field matching and use of more than one modality. Tomotherapy treatment plans were generated and are compared to plans for treatment of the same patient on a linac. The resulting tomotherapy plans show more homogeneous target dose and improved critical structure dose when compared to state-of-the-art linac techniques. Target equivalent uniform dose (EUD) for the best tomotherapy plan was slightly higher than for the linac plan, while the volume of brain tissue receiving over 30 Gy was reduced by two thirds. Furthermore, the tomotherapy plan can be more reliably delivered than linac treatments, because the patient is aligned prior to each treatment based on megavoltage computed tomography (MVCT)
Computer-assisted total hip navigation.
Wixson, Richard L
Accurate implant placement in total hip replacement is important in avoiding dislocation, impingement, and edge-loading throughout the patient's postoperative functional range of motion. Current implants and bearing surfaces now provide the potential for prolonged longevity of the reconstruction, which can be compromised by malposition of the components outside of designated "safe zones." Computer-assisted hip navigation offers the potential for more accurate placement of hip components and control of leg length and offset. Systems are now available that allow registration of the bony anatomy based on preoperative CT images, intraoperative fluoroscopic images, or imageless techniques based on palpation of the landmarks. In each of these approaches, cup position has been based on coordinate systems formed by identification of the anterior pelvic frontal plane. All systems have shown improved accuracy of acetabular cup placement compared with conventional manual techniques. Cup anteversion is less accurate than cup abduction with the imageless approach. Measurements made with the use of navigation systems also have shown a large variation in pelvic tilt or pelvic flexion-extension in series of cases, which can affect the appropriate cup position for each patient. The results of computer-assisted navigation in the future may be improved by incorporation of measurements of each patient's pelvic tilt, femoral stem position, and hip kinematics. PMID:18399618
Total least squares for anomalous change detection
Theiler, James P [Los Alamos National Laboratory; Matsekh, Anna M [Los Alamos National Laboratory
A family of difference-based anomalous change detection algorithms is derived from a total least squares (TLSQ) framework. This provides an alternative to the well-known chronochrome algorithm, which is derived from ordinary least squares. In both cases, the most anomalous changes are identified with the pixels that exhibit the largest residuals with respect to the regression of the two images against each other. The family of TLSQ-based anomalous change detectors is shown to be equivalent to the subspace RX formulation for straight anomaly detection, but applied to the stacked space. However, this family is not invariant to linear coordinate transforms. On the other hand, whitened TLSQ is coordinate invariant, and furthermore it is shown to be equivalent to the optimized covariance equalization algorithm. What whitened TLSQ offers, in addition to connecting with a common language the derivations of two of the most popular anomalous change detection algorithms - chronochrome and covariance equalization - is a generalization of these algorithms with the potential for better performance.
No gut syndrome: near total enterectomy.
Huerta, Sergio; Kukreja, Sachin; Carter, Kristen; Butler, Dale
In adult patients, removal of the entire jejunum and ileum (a near total enterectomy (NTE)) is considered a non-survivable event as patients undergoing this procedure might also suffer from an underlying illness that will lead to bowel necrosis such as septic or cardiac shock and respiratory failure. Parenteral nutrition (PN) dependency with its associated complications and quality of life issues further complicates management decisions in this group of patients. In the following report, we discuss our institutional experience with NTE and present a comprehensive review of the literature with patients undergoing NTE with the establishment of bowel continuity and successful outcomes even in cases dating as far back as the 1950s, over a decade prior to the implementation of PN. Review of the literature revealed 26 cases of NTE. Most of these patients are young (46.7 years old), and 57 % are women. These patients were reported to be alive at 21 months of follow-up. In this report, we present an individual 51 months following NTE. We also document the oldest patient receiving an NTE (76 years old). Both of these patients are alive on home PN. In cases where there is hemodynamic stability and patients request to continue with further care, the possibility of a NTE with bowel continuity and life-long PN might be entertained. PMID:25791906
Physical rehabilitation after total joint arthroplasty in companion animals.
Marcellin-Little, Denis J; Doyle, Nancy D; Pyke, Joanna Freeman
Patients who have total joint arthroplasty have varying needs related to rehabilitation. In the short term, rehabilitation should be used in all dogs to identify high-risk patients and to minimize the likelihood of postoperative complications. Many patients undergoing total hip replacement recover uneventfully without needing long-term physiotherapy. All patients undergoing total knee replacement and total elbow replacement need rehabilitation to restore limb use and maximize their functional recovery. This article presents rehabilitation considerations for companion animals undergoing total hip replacement, total knee replacement, and total elbow replacement; postoperative complications and how to mitigate risks; and anticipated patient outcomes. PMID:25432684
-preserving denoising methods: ┬Ę wavelet soft thresholding [22], ┬Ę space-discrete total variation (TV) diffusion [3, 4 called SIDEs are four useful techniques for discontinuity preserving denoising of signals and images-like artifacts for multiscale Haar wavelet shrinkage by scaling the thresholds. Finally, we present experiments
Hybrid Total Knee Arthroplasty Revisited: Midterm Followup of Hybrid versus Cemented Fixation in Total Knee Arthroplasty
Pelt, Christopher E.; Gililland, Jeremy M.; Doble, Justin; Stronach, Benjamin M.; Peters, Christopher L.
The optimal method of fixation in total knee arthroplasty is still debated. Hybrid total knee arthroplasty (TKA), with cemented tibial and cementless femoral components, is a proposed method of fixation to improve outcomes. Although several studies have shown favorable outcomes, there is still lack of consensus in the literature. We hypothesized that hybrid TKA yields similar clinical, radiographic, and survivorship results compared to fully cemented TKA. The clinical and radiographic outcomes of 304 cruciate retaining TKAs with minimum two-year followup, including 193 hybrid (mean followup of 4.1 years) and fully cemented TKAs (mean followup of 3.2 years) were evaluated. Knee society scores were similar between the two groups. The total number of femoral radiolucencies was also similar between the two groups, while a greater number of femoral Zone 4 radiolucencies were seen in the cemented group (9% versus 1.6%, P = 0.005). The hybrid group demonstrated a 99.2% survival rate of the femoral component out to seven years for aseptic loosening. No significant difference in survivorship was seen between the groups for all cause or aseptic failure at seven years. We conclude that hybrid fixation leads to similar intermediate-term outcomes as fully cemented components and remains a viable option in total knee arthroplasty. PMID:24224179
38 CFR 3.340 - Total and permanent total ratings and unemployability.
Code of Federal Regulations, 2011 CFR
...or sight, or the person is in the strict sense permanently helpless or bedridden, or when it is reasonably certain that a subsidence of the acute or temporary symptoms will be followed by irreducible totality of disability by way of residuals. The age...
38 CFR 3.340 - Total and permanent total ratings and unemployability.
Code of Federal Regulations, 2013 CFR
...or sight, or the person is in the strict sense permanently helpless or bedridden, or when it is reasonably certain that a subsidence of the acute or temporary symptoms will be followed by irreducible totality of disability by way of residuals. The age...
On the Equivalence of Soft Wavelet Shrinkage, Total Variation Diffusion, Total Variation Regularization, and SIDEs
Gabriele Steidl; Joachim Weickert; Thomas Brox; Pavel Mrßzek; Martin Welk
Soft wavelet shrinkage, total variation (TV) diffusion, TV regularization, and a dynamical system called SIDEs are four useful techniques for discontinuity preserving denoising of signals and images. In this paper we investigate under which circumstances these methods are equivalent in the one-dimensional case. First, we prove that Haar wavelet shrinkage on a single scale is equivalent to a single step
Determining total phenolic content and total antioxidant capacity of loquat cultivars grown in Hatay
Polat, A. Aytekin; Ūali?kan, O?uzhan; Serńe, Sedat; Sarańo?lu, Onur; Kaya, Cemal; ųzgen, Mustafa
Several fruit characteristics of five loquat (Eriobotrya japonica (Thunb.) Lindl.) cultivars/selections grown in D÷rtyol, Hatay, Turkey were investigated in 2008. The cultivars/selections included æBaduna 5Æ, G³zelyurt 1, æHafif Ūukurg÷bekÆ, æOttaviani,Æ and Type 1. The characteristics evaluated included fruit weight, width, length, seed number and weight, flesh/seed ratio, total soluble solids (TSS), pH, acidity, total phenolic (TP) content, and total antioxidant capacity (TAC), determined by the ferric reducing antioxidant power (FRAP) assay. The analyses were conducted by three replicates, with 30 fruits in each replicate. The results indicated that there were significant differences among the cultivars, for all the traits tested. For example, æHafif Ūukurg÷bekÆ and æOttavianiÆ had smaller fruits than others, although æHafif Ūukurg÷bekÆ had heavier seeds. The flesh/seed ratio was the highest in Type 1, while æHafif Ūukurg÷bekÆ had the highest pH and high soluble solids. æBaduna 5Æ and æHafif Ūukurg÷bekÆ had the highest acidity. The TP ranged from 129 (æBaduna 5Æ) to 578 (æHafif Ūukurg÷bekÆ) mg gallic acid equivalent (GAE)/kg fresh fruit (fw). æHafif Ūukurg÷bekÆ also had the highest FRAP mean (12.1 mmol Trolox Equivalent (TE)/kg fw). The results suggest that loquat cultivars have a variable range of TP content and a relatively high total antioxidant capacity, which is crucial for human health. PMID:20548929
Determining total phenolic content and total antioxidant capacity of loquat cultivars grown in Hatay.
Polat, A Aytekin; Cali?kan, O?uzhan; Serńe, Sedat; Sarańo?lu, Onur; Kaya, Cemal; Ozgen, Mustafa
Several fruit characteristics of five loquat (Eriobotrya japonica (Thunb.) Lindl.) cultivars/selections grown in D÷rtyol, Hatay, Turkey were investigated in 2008. The cultivars/selections included 'Baduna 5', G³zelyurt 1, 'Hafif Cukurg÷bek', 'Ottaviani,' and Type 1. The characteristics evaluated included fruit weight, width, length, seed number and weight, flesh/seed ratio, total soluble solids (TSS), pH, acidity, total phenolic (TP) content, and total antioxidant capacity (TAC), determined by the ferric reducing antioxidant power (FRAP) assay. The analyses were conducted by three replicates, with 30 fruits in each replicate. The results indicated that there were significant differences among the cultivars, for all the traits tested. For example, 'Hafif Cukurg÷bek' and 'Ottaviani' had smaller fruits than others, although 'Hafif Cukurg÷bek' had heavier seeds. The flesh/seed ratio was the highest in Type 1, while 'Hafif Cukurg÷bek' had the highest pH and high soluble solids. 'Baduna 5' and 'Hafif Cukurg÷bek' had the highest acidity. The TP ranged from 129 ('Baduna 5') to 578 ('Hafif Cukurg÷bek') mg gallic acid equivalent (GAE)/kg fresh fruit (fw). 'Hafif Cukurg÷bek' also had the highest FRAP mean (12.1 mmol Trolox Equivalent (TE)/kg fw). The results suggest that loquat cultivars have a variable range of TP content and a relatively high total antioxidant capacity, which is crucial for human health. PMID:20548929
About Total Lubricants USA, Inc. Headquartered in Linden, New Jersey, Total Lubricants USA provides
Fisher, Kathleen
-standard enterprise software Networking Solution SAP ERP software hosted and managed on a virtualized platform that infrastructure with an in-house team of just two people. When the company's original SAP hosting provider left system changes and enhancements. Solution Total Lubricants, USA chose AT&T to host its SAP applications
The diameter of total domination vertex critical graphs Wayne Goddard
Goddard, Wayne
S is a dominating set if N[S] = V , and a total dominating set if N(S) = V . For sets S, T V , S totally dominates T if T N(S). The minimum cardinality of a total dominating set is the total domination number, denoted t(G). A total dominating set of cardinality t(G) we call a t(G)-set. For a detailed treatment of this parameter
Infection after primary total hip arthroplasty.
Lindeque, Bennie; Hartman, Zach; Noshchenko, Andriy; Cruse, Margaret
The number of primary total hip arthroplasties (THAs) performed in the United States each year continues to climb, as does the incidence of infectious complications. The changing profile of antibiotic-resistant bacteria has made preventing and treating primary THA infections increasingly complex. The goal of this review was to summarize (1) the published data concerning the risk of surgical site infection (SSI) after primary THA by type of bacteria and (2) the effect of potentially modifying factors. The Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, EMBASE, Web of Science, and PubMed were searched. Studies dated between 2001 and 2011 examining primary THA in adults were included. Meta-analysis of the collected data was performed. The pooled SSI rate was 2.5% (95% confidence interval [Cl], 1.4%-4.4%; P<.001; n=28,883). The pooled deep prosthetic joint infection (PJI) rate was 0.9% (95% Cl, 0.4%-2.2%; P<.001; n=28,883). The pooled rate of methicillin-resistant Staphylococcus aureus SSI was 0.5% (95% Cl, 0.2%-1.5%; P<.001; n=26,703). This is approximately 20% of all SSI cases. The pooled rate of intraoperative bacterial wound contamination was 16.9% (95% Cl, 6.6%-36.8%; P=.003; n=2180). All these results had significant heterogeneity. The postoperative risk of SSI was significantly associated with intraoperative bacterial surgical wound contamination (pooled rate ratio, 2.5; 95% Cl, 1.4%-4.6%; P=.001; n=19,049). PMID:24762833
Implantation of the syncardia total artificial heart.
Tang, Daniel G; Shah, Keyur B; Hess, Micheal L; Kasirajan, Vigneshwar
With advances in technology, the use of mechanical circulatory support devices for end stage heart failure has rapidly increased. The vast majority of such patients are generally well served by left ventricular assist devices (LVADs). However, a subset of patients with late stage biventricular failure or other significant anatomic lesions are not adequately treated by isolated left ventricular mechanical support. Examples of concomitant cardiac pathology that may be better treated by resection and TAH replacement includes: post infarction ventricular septal defect,Āaortic root aneurysm / dissection, cardiac allograft failure, massive ventricular thrombus, refractory malignant arrhythmias (independent of filling pressures), hypertrophic / restrictive cardiomyopathy, and complex congenital heart disease. Patients often present with cardiogenic shock and multi system organ dysfunction. Excision of both ventricles and orthotopic replacement with a total artificial heart (TAH) is an effective, albeit extreme, therapy for rapid restoration of blood flow and resuscitation. Perioperative management is focused on end organ resuscitation and physical rehabilitation. In addition to the usual concerns of infection, bleeding, and thromboembolism common to all mechanically supported patients, TAH patients face unique risks with regard to renal failure and anemia. Supplementation of the abrupt decrease in brain natriuretic peptide following ventriculectomy appears to have protective renal effects. Anemia following TAH implantation can be profound and persistent. Nonetheless, the anemia is generally well tolerated and transfusion are limited to avoid HLA sensitization. Until recently, TAH patients were confined as inpatients tethered to a 500 lb pneumatic console driver. Recent introduction of a backpack sized portable driver (currently under clinical trial) has enabled patients to be discharged home and even return to work. Despite the profound presentation of these sick patients, there is a 79-87% success in bridge to transplantation. PMID:25079004
Minnows can acclimate to total residual chlorine
Lotts, J.W. Jr.; Stewart, A.J. [Oak Ridge National Lab., TN (United States). Environmental Sciences Div.
Observations in a chlorine-contaminated stream in eastern Tennessee revealed several species of fish in areas where total residual chlorine (TRC) concentrations were often great enough to be lethal, based on the results of other studies. The authors used in situ and laboratory experiments to test the hypothesis that minnows could acclimate to TRC. Acclimation was assessed by time-to-death for fish exposed to a single lethal regime of TRC. In in situ experiments, striped shiner and central stoneroller minnows collected from East Fork Poplar Creek at a TRC-contaminated site and a site farther downstream, where TRC was below detection, were caged at sites in the stream where TRC concentrations were either nil or great enough to be lethal. At the cage with high TRC, minnows collected from the ``TRC-free`` site survived two to four times longer (15.8 h vs. 6.1 h) than the same species from the ``TRC-free`` site. In laboratory experiments, golden shiner minnows were exposed to TRC in a stepwise increasing concentration regime (0.04 mg/L during week 1, 0.08 mg/L during week 2, and 0.12 mg/L during week 3) before being challenged-tested with a lethal concentration of TRC. Minnows that had been previously exposed to TRC survived longer than controls in each test, and the magnitude of the mean time to death increased as the TRC concentration and duration of exposure increased (1.2-, 2.5-, and 3.9-fold increases for weeks 1, 2, and 3, respectively). Another experiment with golden shiner minnows showed that a 21-d exposure to TRC at a low concentration (0.04 mg/L) only slightly increased their tolerance to TRC. Thus, several minnow species apparently can acclimate, fairly rapidly, to TRC. This study may help explain why fish kills are less common than expected in TRC-contaminated streams.
Kinematically versus mechanically aligned total knee arthroplasty.
Dossett, H Gene; Swartz, George J; Estrada, Nicolette A; LeFevre, George W; Kwasman, Bertram G
The purpose of this study was to compare 2 alignment methods for total knee arthroplasty (TKA): kinematic alignment with the use of patient-specific guides and mechanical alignment with conventional instruments. A randomized, controlled trial of 41 kinematically aligned and 41 mechanically aligned patients was conducted with the patient, radiographic evaluator, and clinical evaluator blinded to the alignment technique. Radiographic measurements were made from long-leg computer tomography scanograms. Clinical outcome scores and motion were measured preoperatively and 6 months postoperatively. The hip-knee-ankle angle (0.3░ difference; P=.693) and anatomic angle of the knee (0.8░ difference; P=.131) were similar for both groups. In the kinematically aligned group, the angle of the femoral component was 2.4░ more valgus (P<.000) and the angle of the tibial component was 2.3░ more varus (P<.000) than the mechanically aligned group. At 6 months postoperatively, the Western Ontario and McMaster Universities Osteoarthritis Index score was 16 points better (P<.000), Oxford Score was 7 points better (P=.001), combined Knee Society Score was 25 points better (P=.001), and flexion was 5.0░ greater (P=.043) in the kinematically aligned group than in the mechanically aligned group.Our findings suggest that the risk of early failure related to limb or knee alignment should be similar in kinematic and mechanically aligned TKA. More anatomic alignment of the implant was associated with better flexion and better clinical outcome scores in the kinematically aligned group. PMID:22310400
Totally implantable artificial organ: cardiac prosthesis.
Nosķ, Y
This article reviews the current status of completely implantable cardiac prostheses, with an emphasis on those systems presently under development at The Cleveland Clinic Foundation (CCF). Such devices have been one of the final goals of artificial heart research since 1957, when Dr. Kolff initiated these studies in Cleveland. Although earlier plans aimed at using radioisotopes as the energy source, more recently, due to public opinion and sociopolitical influences, the shift has been towards exclusive use of electrically activated energy converters. These systems can be roughly broken down into two groups according to the powertrain configuration. In the first group, electric heating coils maintain liquid salts in thermal batteries at temperatures close to 500 degrees C. This thermal energy is then converted (through a Stirling cycle) to mechanical motion of the pusher plate (PP) which in turn acts on the blood. Two such systems (emphasized in this article) are under development here at CCF in joint efforts with Nimbus Corporation and the University of Washington, respectively. In the second group of ventricular assist systems, electric energy is converted directly to PP motion through rotating cams, solenoids, or electrohydraulic transmission systems. At least four American contractors are working at the preclinical stage on this group of devices. One in particular, the CCF-Nimbus system, consisting of a biolized surface blood pump, an electrohydraulic energy converter, and a compliance chamber to handle the variable volume behind the PP, is described in depth in this discussion. In terms of future prospects, it is forecasted that by 1988, the completely implantable VAS will be used clinically, and that by 1994, a specially designed total artificial heart (nontethered patient) would be ready for human use. PMID:3718273
Total lymphoid irradiation for multiple sclerosis
Devereux, C.K.; Vidaver, R.; Hafstein, M.P.; Zito, G.; Troiano, R.; Dowling, P.C.; Cook, S.D.
Although chemical immunosuppression has been shown to benefit patients with chronic progressive multiple sclerosis (MS), it appears that chemotherapy has an appreciable oncogenic potential in patients with multiple sclerosis. Accordingly, we developed a modified total lymphoid irradiation (TLI) regimen designed to reduce toxicity and applied it to a randomized double blind trial of TLI or sham irradiation in MS. Standard TLI regimens were modified to reduce dose to 1,980 rad, lowering the superior mantle margin to midway between the thyroid cartilage and angle of the mandible (to avert xerostomia) and the lower margin of the mantle field to the inferior margin of L1 (to reduce gastrointestinal toxicity by dividing abdominal radiation between mantle and inverted Y), limiting spinal cord dose to 1,000 rad by custom-made spine blocks in the mantle and upper 2 cm of inverted Y fields, and also protecting the left kidney even if part of the spleen were shielded. Clinical efficacy was documented by the less frequent functional scale deterioration of 20 TLI treated patients with chronic progressive MS compared to to 20 sham-irradiated progressive MS patients after 12 months (16% versus 55%, p less than 0.03), 18 months (28% versus 63%, p less than 0.03), and 24 months (44% versus 74%, N.S.). Therapeutic benefit during 3 years follow-up was related to the reduction in lymphocyte count 3 months post-irradiation (p less than 0.02). Toxicity was generally mild and transient, with no instance of xerostomia, pericarditis, herpes zoster, or need to terminate treatment in TLI patients. However, menopause was induced in 2 patients and staphylococcal pneumonia in one.
Antioxidant activity, total phenolic and total flavonoid contents of whole plant extracts Torilis leptophylla L
Background The aim of this study was to screen various solvent extracts of whole plant of Torilis leptophylla to display potent antioxidant activity in vitro and in vivo, total phenolic and flavonoid contents in order to find possible sources for future novel antioxidants in food and pharmaceutical formulations. Material and methods A detailed study was performed on the antioxidant activity of the methanol extract of whole plant of Torilis leptophylla (TLM) and its derived fractions {n-hexane (TLH), chloroform (TLC) ethyl acetate (TLE) n-butanol (TLB) and residual aqueous fraction (TLA)} by in vitro chemical analyses and carbon tetrachloride (CCl4) induced hepatic injuries (lipid peroxidation and glutathione contents) in male Sprague-Dawley rat. The total yield, total phenolic (TPC) and total flavonoid contents (TFC) of all the fractions were also determined. TLM was also subjected to preliminary phytochemical screening test for various constituents. Results The total phenolic contents (TPC) (121.9▒3.1 mg GAE/g extract) of TLM while total flavonoid contents (TFC) of TLE (60.9 ▒2.2 mg RTE/g extract) were found significantly higher as compared to other solvent fractions. Phytochemical screening of TLM revealed the presence of alkaloids, anthraquinones, cardiac glycosides, coumarins, flavonoids, saponins, phlobatannins, tannins and terpenoids. The EC50 values based on the DPPH (41.0▒1 ?g/ml), ABTS (10.0▒0.9 ?g/ml) and phosphomolybdate (10.7▒2 ?g/ml) for TLB, hydroxyl radicals (8.0▒1 ?g/ml) for TLC, superoxide radicals (57.0▒0.3 ?g/ml) for TLM and hydrogen peroxide radicals (68.0▒2 ?g/ml) for TLE were generally lower showing potential antioxidant properties. A significant but marginal positive correlation was found between TPC and EC50 values for DPPH, hydroxyl, phosphomolybdate and ABTS, whereas another weak and positive correlation was determined between TFC and EC50 values for superoxide anion and hydroxyl radicals. Results of in vivo experiment revealed that administration of CCl4 caused a significant increase in lipid peroxidation (TBARS) while decrease in GSH contents of liver. In contrast, TLM (200 mg/kg bw) and silymarin (50 mg/kg bw) co-treatment effectively prevented these alterations and maintained the antioxidant status. Conclusion Data from present results revealed that Torilis leptophylla act as an antioxidant agent due to its free radical scavenging and cytoprotective activity. PMID:23153304
Total Phenolic, Total Flavonoids, Antioxidant and Antimicrobial Activities of Scrophularia Striata Boiss Extracts
Mahboubi, Mohaddese; Kazempour, Nastaran; Boland Nazar, Ali Reza
Background Scrophularia striata (Scrophulariaceae family) is an herbaceous plant that is traditionally used for treatment of microbial infections. Objectives Antimicrobial and antioxidant activity of different extracts (methanolic, ethanolic, aqueous and ethyl acetate) from S. striata aerial parts was evaluated. Materials and Methods The antimicrobial activity of different extracts from S. striata was evaluated against a large number of bacteria and fungi by micro broth dilution. Total phenolic and flavonoid contents were measured and their antioxidant activities evaluated by DPPH assay and beta carotene linoleic acid test. Results Antimicrobial screening exhibited the positive relation between the total phenolic content and its antimicrobial activity but their antioxidant activity had a negative relation. Conclusions Further studies are recommended against clinical isolate of sensitive bacteria and deep investigation on flavonoid and phenolic compounds of S. striata and detecting the antioxidant portion in aqueous extract. PMID:24624181
Power Spectra of the Total Occupancy in the Totally Asymmetric Simple Exclusion Process
NASA Astrophysics Data System (ADS)
Adams, D. A.; Zia, R. K. P.; Schmittmann, B.
As a solvable and broadly applicable model system, the totally asymmetric exclusion process enjoys iconic status in the theory of nonequilibrium phase transitions. Here, we focus on the time dependence of the total number of particles on a 1-dimensional open lattice and its power spectrum. Using both Monte Carlo simulations and analytic methods, we explore its behavior in different characteristic regimes. In the maximal current phase and on the coexistence line (between high and low density phases), the power spectrum displays algebraic decay, with exponents -1.62 and -2.00, respectively. Deep within the high and low density phases, we find pronounced oscillations, which damp into power laws. This behavior can be understood in terms of driven biased diffusion with conserved noise in the bulk.
Evaluation of total antioxidant potential (TRAP) and total antioxidant reactivity from luminol-enhanced chemiluminescence measurements
Eduardo Lissi; Marta Salim-Hanna; Carlos Pascual; Maria D. del Castillo
The effect of antioxidants and biological fluids on the intensity of luminol induced chemiluminescence by radicals derived from the thermolysis of 2,2?-azo-bis(2-amidinopropane) has been employed to monitor TRAP and TOTAL ANTIOXIDANT REACTIVITY (TAR) levels. The latter parameter, which considers not only the quantity of oxidants but also their reactivity, is considered a potentially more useful index of the antioxidant status
Two-directional total synthesis of efomycine M and formal total synthesis of elaiolide
Roland Barth; Johann Mulzer
The anti-inflammatory agent efomycine M (1) has been synthesized from macrodilactone 38 and vinyliodide 42 by a two-directional total synthesis in 17 steps over the longest linear sequence with an overall yield of 7%. The C2-symmetric macrodiolide 38 has been prepared by Yamaguchi macrolactonization of seco-acid 26. The central stereopentad of 1 was obtained by a highly efficient anti-aldol reaction
T.Q.M.: Total Quality Management or total quackery and mismanagement
Stallard, T.F.
The concept of total quality management (TQM) is outlined. The basic idea of TQM is that quality products and services will lead a company to greater financial success than will mass quantities of inferior products. The following topics are outlined: standard labs and TQM;TQM benefits to be gained by standard labs; TQM at standard labs is quality improvement system (QIS), TQM, reduces of attitude. QIS team leader training agenda; and the safety connection.
Autonoma de Madrid, Universidad
Autonoma de Madrid, Universidad
Zooplankton and the total phosphorus chlorophyll a relationship: hierarchical Bayesian
Notre Dame, University of
Zooplankton and the total phosphorus Ł chlorophyll a relationship: hierarchical Bayesian analysis: Zooplankton grazing is important in resolving residual variation around the total phosphorus Ł chlorophyll a relationship. In empirical studies, zooplankton body size is often a better predictor of residual variation
Joint Line Reconstruction in Navigated Total Knee Arthroplasty Revision
Revision Total Knee Arthroplasty Because of; Loosening; Instability; Impingement; or Other Reasons Accepted as Indications for TKA Exchange.; The Focus is to Determine the Precision of Joint Line Restoration in Navigated vs. Conventional Revision Total Knee Arthroplasty
Orde r For m Titl e Order total
Hayden, Nancy J.
Orde r For m Titl e Order total: Tax: Shipping: Total: Item # Description Qty. Price Subtotal Name and will be checked upon arrival. If the sheep is found to be unhealthy or is transported as an infected animal
24 CFR 886.308 - Maximum total annual contract commitment.
Code of Federal Regulations, 2010 CFR
...total annual contract commitment. 886.308 Section...total annual contract commitment. (a) Number of units assisted. Based...for all the contract units in the project...maximum annual contract commitment per year...
20 CFR 410.412 - ōTotal disabilityö defined.
Code of Federal Regulations, 2010 CFR
... Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL COAL MINE HEALTH AND SAFETY ACT OF 1969, TITLE IV-BLACK LUNG BENEFITS (1969- ) Total Disability or Death Due to Pneumoconiosis ¦ 410.412 ōTotal disabilityö defined....
Autonoma de Madrid, Universidad
MUJERES ( * ) TOTAL ANATOM═A, HISTOLOG═A Y NEUROCIENCIA 4 10 BIOLOG═A 12 20 BIOLOG═A MOLECULAR 41 Neurociencia 1 0 BioquĒmica 20 18 Medicina 30 23 FarmacologĒa y Terapķutica 8 4 TOTAL MEDICINA 69 54 PsicologĒa
Bounds on the Total Redundance and Efficiency of a Graph
Goddard, Wayne
Bounds on the Total Redundance and Efficiency of a Graph Wayne Goddard, University of Natal, Durban. Swart, University of Natal, Durban Abstract For a graph G with vertex set V , the total redundance, TR
Diabetic Neuropathy: What is a Total Contact Cast?
MENU Return to Web version Diabetic Neuropathy | What is a Total Contact Cast? What is a total contact cast? A total contact cast is a cast used to treat ulcers (serious, deep sores) on a personÆs foot. It consists of a fiberglass shell that fits around your leg and foot very ...