A method and neurostimulation control system for operating two leads disposed adjacent tissue of a patient are provided. A plurality of cross-lead electrical parameters are measured to generate a measured electrical profile of the electrode leads. A plurality of cross-lead electrical parameters are estimated to generate a first reference electrical profile for the electrode leads in a first known staggered configuration. The first reference electrical profile is spatially shifted to generate a second reference electrical profile for the electrode leads in a second known staggered configuration. The measured electrical profile is compared to the first and second reference electrical profiles, and a longitudinal stagger between the electrode leads is quantified based on the comparison.

Implantable neurostimulation systems have proven therapeutic in a wide variety of diseases and disorders. Pacemakers and Implantable Cardiac Defibrillators (ICDs) have proven highly effective in the treatment of a number of cardiac conditions (e.g., arrhythmias). Spinal Cord Stimulation (SCS) systems have long been accepted as a therapeutic modality for the treatment of chronic pain syndromes, and the application of tissue stimulation has begun to expand to additional applications such as angina pectoralis and incontinence. Deep Brain Stimulation (DBS) has also been applied therapeutically for well over a decade for the treatment of refractory chronic pain syndromes, and DBS has also recently been applied in additional areas such as movement disorders and epilepsy. Further, in recent investigations Peripheral Nerve Stimulation (PNS) systems have demonstrated efficacy in the treatment of chronic pain syndromes and incontinence, and a number of additional applications are currently under investigation. Also, Functional Electrical Stimulation (FES) systems such as the Freehand system by NeuroControl (Cleveland, Ohio) have been applied to restore some functionality to paralyzed extremities in spinal cord injury patients.
These implantable neurostimulation systems typically include one or more electrode carrying stimulation leads, which are implanted at the desired stimulation site, and a neurostimulator (e.g., an implantable pulse generator (IPG)) implanted remotely from the stimulation site, but coupled either directly to the stimulation lead(s) or indirectly to the stimulation lead(s) via a lead extension. Thus, electrical pulses can be delivered from the neurostimulator to the stimulation leads to stimulate the tissue and provide the desired efficacious therapy to the patient. The neurostimulation system may further comprise a handheld patient programmer in the form of a remote control (RC) to remotely instruct the neurostimulator to generate electrical stimulation pulses in accordance with selected stimulation parameters. The RC may, itself, be programmed by a clinician, for example, by using a clinician's programmer (CP), which typically includes a general purpose computer, such as a laptop, with a programming software package installed thereon.
In the context of an SCS procedure, one or more stimulation leads are introduced through the patient's back into the epidural space, such that the electrodes carried by the leads are arranged in a desired pattern and spacing to create an electrode array. One type of commercially available stimulation leads is a percutaneous lead, which comprises a cylindrical body with ring electrodes, and can be introduced into contact with the affected spinal tissue through a Touhy-like needle, which passes through the skin, between the desired vertebrae, and into the epidural space above the dura layer. For unilateral pain, a percutaneous lead is placed on the corresponding lateral side of the spinal cord. For bilateral pain, a percutaneous lead is placed down the midline of the spinal cord, or two or more percutaneous leads are placed down the respective sides of the midline of the spinal cord, and if a third lead is used, down the midline of the special cord. After proper placement of the stimulation leads at the target area of the spinal cord, the leads are anchored in place at an exit site to prevent movement of the stimulation leads. To facilitate the location of the neurostimulator away from the exit point of the stimulation leads, lead extensions are sometimes used.
The stimulation leads, or the lead extensions, are then connected to the IPG, which can then be operated to generate electrical pulses that are delivered, through the electrodes, to the targeted tissue, and in particular, the dorsal column and dorsal root fibers within the spinal cord. The stimulation creates the sensation known as paresthesia, which can be characterized as an alternative sensation that replaces the pain signals sensed by the patient. Intra-operatively (i.e., during the surgical procedure), the neurostimulator may be operated to test the effect of stimulation and adjust the parameters of the stimulation for optimal pain relief. The patient may provide verbal feedback regarding the presence of paresthesia over the pain area, and based on this feedback, the lead positions may be adjusted and re-anchored if necessary. A computer program, such as Bionic Navigator®, available from Boston Scientific Neuromodulation Corporation, can be incorporated in a clinician's programmer (CP) (briefly discussed above) to facilitate selection of the stimulation parameters. Any incisions are then closed to fully implant the system. Post-operatively (i.e., after the surgical procedure has been completed), a clinician can adjust the stimulation parameters using the computerized programming system to re-optimize the therapy.
Multi-lead configurations have been increasingly used in electrical stimulation applications (e.g., neurostimulation, cardiac resynchronization therapy, etc.). In the neurostimulation application of SCS, the use of multiple leads increases the stimulation area and penetration depth (therefore coverage), as well as enables more combinations of anodic and cathodic electrodes for stimulation, such as transverse multipolar (bipolar, tripolar, or quadra-polar) stimulation, in addition to any longitudinal single lead configuration.
Several studies have demonstrated the advantage of using narrowly spaced, parallel leads placed symmetrically on both sides of the physiological midline in improving penetration and paresthesia coverage (see J. J. Struijk and J. Holsheimer, Tripolar Spinal Cord Stimulation: Theoretical Performance of a Dual Channel System, Medical and Biological Engineering and Computing, Vol. 34, No. 4, 1996, pp. 273-279; J. Holsheimer, B. Nuttin, G. King, W. Wesselink, J. Gybels, and P. de Sutter, Clinical Evaluation of Paresthesia Steering with a New System for Spinal Cord Stimulation, Neurosurgery, Vol. 42, No. 3, 1998, pp. 541-549; Holsheimer J., Wesselink, W. A., Optimum Electrode Geometry for Spinal Cord Stimulation: the Narrow Bipole and Tripole, Medical and Biological Engineering and Computing, Vol. 35, 1997, pp. 493-497).
The efficacy of SCS is related to the ability to stimulate the spinal cord tissue corresponding to evoked paresthesia in the region of the body where the patient experiences pain. Thus, the working clinical paradigm is that achievement of an effective result from SCS depends on the neurostimulation lead or leads being placed in a location (both longitudinal and lateral) relative to the spinal tissue such that the electrical stimulation will induce paresthesia located in approximately the same place in the patient's body as the pain (i.e., the target of treatment). If a lead is not correctly positioned, it is possible that the patient will receive little or no benefit from an implanted SCS system. Thus, correct lead placement can mean the difference between effective and ineffective pain therapy.
When lead migration occurs, proper paresthesia coverage can most often be recaptured by reprogramming the IPG, e.g., by using the Bionic Navigator® software. When multiple percutaneous leads are used, programming of the IPG often requires the knowledge of the relative positions between the leads in order to properly place the poles of the generated electrical field. Such information, however, is not readily available to the programmer unless fluoroscopic imaging is performed. Fluoroscopic imaging involves ionized radiation, adds time and cost, and requires a bulky instrument, both of which may limit its use in the clinical setting, and effectively prevent its use outside of the clinical setting. If such lead placement is not detected in a timely manner before the system is fully implanted, it may result in inefficient therapy and possibly require a second surgery for lead revision. Thus, lead migration continues to be the most common technical complication of spinal cord stimulation therapy. A literature review suggested the incident rate of lead migration was approximately 13.2% (see T. Cameron, Safety and Efficacy of Spinal Cord Stimulation for the Treatment of Chronic Pain: a 20-Year Literature Review, J Neurosurg: Spine 2004, 100: 254-267).
Currently, the relative positions of multiple leads can be electronically estimated by measuring electrical signals between lead electrodes. For example, the Bionic Navigator® software uses an Electronically Generated Lead (EGL) Scan that estimates the relative lead positions by examining the profiles of electrical field potential measured from the electrodes that is generated due to the current flow in the medium. In particular, the EGL scan feature detects the stagger of the leads by comparing the profile of measured cross-lead field potentials with those calculated from a Finite Element Model (FEM) for known lead configurations. The FEM model provides a prediction of the field potentials that are expected to be measured on the electrodes, and it takes into account the geometric properties and electrical behaviors of the various elements in the spinal cord, as well as the boundary conditions imposed on the field potentials generated in the human body. The lead stagger can be determined by comparing the profile of the measured cross-lead field potentials with those computed from the FEM model for several known lead configurations. The lead configuration for which the modeled field potential profile best matches the measured field potential profile is designated as the detected lead configuration.
This technology provides an automated means to obtain the information about the relative position of implanted leads without using fluoroscopy. Such information may be used to increase programming accuracy, thus improving the patient outcomes and treatment efficacy. Although the comparison of the measured field potential profile to numerous reference profiles generated by the FEM model is computationally intensive and requires a lot of memory, the CP is embodied in a computer with the processing power and memory necessary to efficiently perform these computations.
As the next generation SCS systems are expected to give the patient more control over their stimulation programs to improve the therapy, as well as to reduce the need for office visits, it has been proposed to incorporate more programming features (previously reserved for CPs) into RCs and IPGs. Just as in the programming of the IPG through a CP, it is also desirable to have the capability of electronically determining the relative lead positions within the RC, which may be needed to properly program the IPG. However, in the case of the EGL Scan feature, the known field potential profiles to which the measured cross-lead field potentials are compared to determine the lead stagger is stored in a database that is loaded during the EGL Scan processing. This presents a potential difficulty in transferring the present EGL Scan features directly into a RC, because it requires memory space for the database storage that may not be available in the RC.
There, thus, remains a need for a technique that determines the relative positions of leads without requiring a large amount of memory space.

System for determining relative position between neurostimulation leads


Present invention depicts a poly-porous (micropore) hollow screws as diffusion chamber filled with core matrix for targeted delivery of growth factors and bone marrow stem cells. The screws comprise at least two parts: the distal part of the screw consists of the tip of the screw made of poly porous material and hollow inside proximally. It has threaded navel attached to the threaded nipple of the distal part of the proximal screw which has the screw head and is made of the solid material of the same kind. The screw head had hexagonal recess targeted for screw driver insertion. Assembly of screw created a chamber in the middle of the screw. The chamber is filled with core matrix consisting of gelatin nano-particles pre-impregnated with BMPs (BMP2/BMP7 for bone or BMP12 for tendon, ligament) and fibrin sealants or Chitosan dispersed with bone marrow stem cells and/or other growth factors. Bioactive protein core material is prepared during the surgery and filled the chamber of the screw by the surgeon. Fibrin sealants or Chitosan will polymerize to form a gel to hold the growth factors and stem cell in place. The screw can be used as the lag screw or other function to provide mechanical fixation in variety of condition. Once the screw implanted in the human body, the fibrin sealant or Chitosin/gelatin nano-particles are gradually degraded and slowly release growth factors and stem cells via micropores of screw to facilitate the bone healing and regeneration. The gelatin nanoparticles and fibril sealant/or Chitosan matrix also serve as the scaffold and platform for bone in-growth to the screw or alternatively, the stem cell inside of screw can regenerate new bone, providing the biological fixation. At the mean time as the bone regenerate and/or in growth, mechanical strength of the screw increased.

Bone is a naturally regenerative tissue possessing the capacity of healing from injury by recapitulating the embryonic skeletal developmental process. However, an estimated 5-10% of fractures fail to recover properly and proceed to delayed union or nonunion due to mechanical instability and/or poor biology (1). The mechanical problem is the one relatively easy one to be solved by external or internal fixation, but the biological issue remains a significant challenge (1). There are few fractures had tendency to undergo process of nonunion due to their unique anatomy. These include femur neck, scaphoid, talus neck, and Jone's fractures.
Femur neck fracture is one of the most common fractures treated surgically in orthopedic surgery. It comprises more than 50% of the hip fractures which is estimated to exceed 500,000 in United States by year 2041 as the population aging (2-34). Surgical fixation of the femur neck fracture is extremely challenging especially when fracture presents in elderly and fracture displaced. Due to poor bone quality and healing power in the elderly, higher rate of fixation failure including mal-union, nonunion and AVN had been reported in the literature in this group which causes high re-operating rate and increasing of the total cost (5, 6). Thus, hemiarthroplasty has been advocated by some surgeon (7). Despite the increasing cost for internal fixation, interestingly, more patient choose internal fixation over hemiarthroplasty based on recent cost-benefit analysis using the willingness to pay technique (8).
Mainstay of current internal fixation of femur neck fracture consists of lag screws and DHS. Lag screw fixation is the most popular technique used for femur fracture in United States. Most surgeons use 3 cancellous screws in an inverted triangular orientation. The inferior screw is recommended to be placed close to the calcar and anterior and posterior superior screw should put close or within 3 mm of the cortex to ensure better purchase. The cannulated screws are used with assistance of guide wire for parallel placement which allows dynamic compression. Lag screw fixation has advantage of minimally invasive insertion, limited disruption of femur head blood supply and superior torsional stability (9). However, strength of lag screw fixation is dependent on the quality of bone on the lateral wall of the proximal femur. Severe osteoporosis in elderly compromise strength of bone in support the screw fixation or in the fracture with vertical fracture line which imposes larger deforming force on the screw surpassing the capacity of screw fixation leads to fixation failure (7).
The challenge of fixation of femur neck fracture is not only come from the poor quality of the bone in the elderly but also from the biology of bone healing. Bone healing is slower in elder patient per se due to senesces of stem cells. The situation worsen in femur neck fracture because the femur neck is enveloped by synovial fluid, thus no periosteal blood supply and fracture disrupting the intraosseous blood circulation to the proximal fragment. Thus, any means to facilitate re-vascularization and bone healing will help to win the battle for racing between loss of reduction and bone healing.
Scaphoid is divided into proximal and distal poles, a tubercle, and the waist. eighty percent of the scaphoid is covered with articular cartilage. The main vascular supply is derived from scaphoid branch of the radial artery entering the dorsal ridge and supply 70%-80% of the scaphoid, including the proximal pole. Scaphoid fracture is the most common carpal fracture. Fracture through the waist or proximal pole disrupted the blood circulation, thus like femur neck fracture, had high incident of delayed or nonunion. Thus, screw fixation is recommended to achieve stable fixation thus revascularization of the proximal pole. Recently, percutaneous technique is advocated to preserve the circulation during the surgery (Kenneth, J Koval ed Hand book of fractures).
Talus fracture is the second in frequency among all tarsal fractures. Similar to the femur neck and scaphoid, majority (70%) of the talus is covered by articular cartilage No muscles originate or insert into the talus. The vascular supply to the talus depend on facial structures to reach talus, thus, in Hawkins' 3-4 talus neck fracture, capsule is disrupted which result in osteonecrosis (Keneth Koval ed Hand book of fractures).
The metadiaphyseal region of the 5th metatarsal is an area of circulatory watershed resulting in limited blood supply. Fracture that occur at the meta-diaphyseal junction about 1.5 to 2.5 cm distal to metatarsal base, are commonly called Jones fracture. Because the comprised blood supply in this area, the fracture is at risk of nonunion. Thus, screw fixation is recommended for athletes to minimize the possibility of nonunion and prolonged restriction from activity (Jay Lieberman AAOS comprehensive review).
Tendon and ligament injury is the common injury in the sport. Healing of the ligament and tendon to the bone tunneling after reconstruction is the slow process resulting in prolonged restriction activity for the athletes to return the games. Speeding up the healing would be significantly beneficial to the survivorship of the graft and the athlete career.
Burst fracture is the fracture compression and flexion injury to the spine lead to the crushed of the vertebrate. The fracture are involved both anterior and middle column of the spine and is considered unstable fracture. The treatment includes the posterior pedicle screw fixation and possible anterior spine fusion. Pedicle screw can efficiently reduce the fracture of the vertebrate body by ligament taxis in most of time. The anterior spine fusion is only necessary to increase strength and support to anterior middle column to release the strain of the pedicle screw so that the later would not fail before the fracture healed. Thus, any means to facilitate the fracture healing may eliminate the need of anterior fixation.
Taking together, the unique injuries described above call for a biological active fixation device that can provide the mechanical strength and had capacity to stimulation healing.
Bone morphogetic proteins (BMPs) are a class of the proteins belonging to TGF beta superfamily and exhibiting potent osteoinductive activity in vivo. BMPs initially identified by their ability to induce ectopic, endochondral bone formation (Urist, 1965). Since then, 18 members of the BMP family have been identified. Structure and characterization of these proteins had been reviewed in detailed in recent patent application. US patent No 20090169592 "Osteogeneic devices and method of use thereof for repair of endonchondral bone and osteochondral defect". BMPs can be isolated in relative pure form by processes described in U.S. Pat. No. 4,294,935, 1981 and U.S. Pat. No. 4,455,256, 1983. Recently, Recombinant human BMP2 and BMP7 is made available by technique described in U.S. Pat. No. 6,150,328, 2000 and U.S. Pat. No. 7,459,527, 2008. Both BMP2 and BMP7 are potent osteoinductive agents, BMP2 either alone or in combination of other graft materials had shown to heal some critical size bone defect or nonunions. BMP2 and BMP7 are currently commercially available and FDA approved for treatment of the lumbar spine fusion and nonunion of the tibia fractures. BMP12, unlike BMP 2 and BMP7, exhibit the potent potential for tendon and ligament regeneration. Although BMPs is able to induce osteogenesis, or tendon/ligament genesis, very high dose is required to achieve such effect if use alone. To efficiently delivery of BMPs and improve their bioavailability, finding a suitable carrier is the major focus of the current research.
Search for the appropriate carrier for delivery of the BMPs started as early as discovery of the methods to purify MMPs. U.S. Pat. No. 4,526,909 to Urist, 1985 disclosed to used polymethylmethacrylate as delivery system for BMPs however, this system proved not working. BMPs are hydrophilic whereas, PMMA is hydrophobic. Most of the BMP will be trapped inside of the PMMA except the outer surface which can release by a leaching mechanism. Furthermore, monomer of PMMA and heat generated by polymerization will denature the protein thus inactivate the osteoinductive active of the BMPs. U.S. Pat. No. 4,596,574 to Urist, 1986 disclosed to use a biodegradable porous ceramics including tricalcium phosphate as carrier to deliver BMPs, it turn out to be great idea, porous ceramic not only able to control drug release but also attract stem cell in-growth thus augment host tissue integration. Porous ceramic is still use in combination of the organic polymers for drug delivery (U.S. Pat. No. 6,949,251). U.S. Pat. No. 4,563,489 disclosed of methods using biodegradable organic polymer, polylactic acid polymer as carrier for delivery of BMPs. it was proposed to use biodegradable material to make implant such screws. The idea is attractive because feature of biodegradability eliminate the possibility of hardware removal, however, this is not feasible because toxic degradation product and lack of mechanical strength. Since the early effort, many new materials have been developed as carrier for BMP delivery. The materials can be classified into two categories organic or inorganic. Inorganic carrier further divided as biodegradable or un-degradable. Most of organic carriers are biodegradable which further divided into hydrophobic or hydrophilic. These materials are used alone or in combination to control the rate BMP release so that bone formation is balance with rate of the biodegradation of the implant without de mechanical strength. The use of these materials is fully elucidated in following US patents (U.S. Pat. Nos. 6,110,484, 6,949,251, 6,544,290, 7,049,348, 7,192,604, 6,949,590). Of all materials tested, however, gelatin is still most promising carrier.
Gelatin is nature polymers derived from denature of type I collagen. Gelatin derived from bovine or porcine has been widely used in pharmaceutical industry as capsule materials and stabilizer, gelatin also used as implant such gel-foam to stop surgical bleeding and demonstrated non-toxic, excellent biocompatibility and biodegradability. More importantly, Both BMP2 and BMP7 bind to the gelatin derived from bone, thus, better retain BMPs in the carrier. Porous form of gelatin is easy accessed by water and stem cells thus serve better as a carrier for BMPs. Recently, FDA approved clinical application of the porous collagen film as a carrier for BMP to enhance spine fusion (BMP-2) or healing of bone defect in nonunion (Medscape today, Carriers for BMPs). US patent NO. 20080294085 to Stamps disclosed collagen sponge rolled biphased ceramic to treat the precollapsed oateonecrosis of the femur head.
With advanced of nanotechnology, gelatin has been used to form a nanoparticles, natotubes and nanofibers. Natoparticle refers to the particles with diameters ranging from 10 nm to 1000 nm. Using nanoparticles as drug delivery system confirms sustained drug delivery, and subcellular action, therefore, significantly enhances the bioavailabilty of the drug. Preparation of gelatin nanoparticles is very simple by two step dissolvation methods. Gelatin nanoparticles are also easy to be crosslinked and chemically modified. Therefore, it has immense potential to be used for as colloidal drug delivery system. Other advantages are: It is inexpensive and can be sterilized (Mohsen, 2008). Study of BMP2 gelatin nanoparticles demonstrated that gelatin nanoparticles stabilize BMP2 for sustained release for a prolonged period of time (6 weeks in vitro and in vivo (Kempen et al Biomaterial 2008). Recently, human recombinant gelatin (rHG) is available as a source for preparation of nanoparticles to decrease risk of mad cow disease and lower the antigenicity. hHG nanoparticles exhibited good biocompatibility and controlled release of FITC-BSA (Young, 2009). Gelatin nanoparticle also exhibits protective effect of basic FGF (Tsutomu, 2007). In present invention, we use gelatin nanoparticle as a carrier for MMPs.
Stem cells refer to the cell able to differentiate into variety of lineage, yet maintain the ability to self renew. Mesenchymal stem cells (MSCs) are the pluripotent or multipotent stem cells capable of differentiating into osteogenic, chondrogenic, adipogenic and other mesenchymal lineages in vitro. MSCs are no specific marker, thus laboratory defined MSCs remains debatable. It is consensus that MSCs does express CD90 and CD105 but not express CD34 and CD 45. This may help for isolation of the MSCs. MSCs existed in many tissues including, adipose, muscles, liver, blood, as well as barrows. Bone marrow is the one of the richest resource for stem cells, and the most frequent donor site for harvesting stem cells for clinical use. The stem cells isolated from bone marrow refer to bone marrow stem cells (BMSCs). BMSCs are osteogenic, implantation of human BMSCs with a carrier into a critical size of bone defect which usually undergoes nonunion healed completely with short amount of the time (U.S. Pat. No. 686,900 to Kadiyala, 2005). Both autologous and allogenic MSCs can be used for orthopaedic surgery, autologous cells are preferred because it is non-immunogenic, easily accessible, sufficient resources available (only need 60 ml v.s 1.5 liter for other purpose). Standard procedure for isolation and purification of the MSCs from bone marrow consists of several steps: collection of the bone marrow aspirates, separation of nucleated cells from red cell, and purification of MSCs from other nucleated cells, clone selection and characterization as it delineated in the U.S. Pat. No. 7,015,037 to Furcht at el, 2006. Purification of the MSCs stem cells takes a few weeks to months to complete which renders multiple procedure and inconvenience for clinical use. Multiple purification steps in an open system can raise the risk of infection. In addition, in vitro differentiation and mutation is also a concern. Thus, application purified MSCs appears less attractive (Marcus et al 2009).
Collection and application of the bone marrow aspirates for bone regeneration and repair is a well know arts for centuries. However, clinical outcome is not consistent. Recent studies have shown that the key to effective clinical outcomes using MSC therapy is to provide that sufficient number of the MSCs cells to the patient which repairs the bone or tissue defects. This refers to "Regenerative MSC Threshod" (Kadiyala, 2005). Bone marrow aspirates are usually collected from the iliac crest. It contains red blood cells, lymphocytes, granucytes, monocytes, fibroblasts, stem cells including bone stem cells which possess only very small percentage of all cell populations. Therefore in order to achieve Regenerative MSC Threshod, a method needs to enrich MSCs in the bone marrows aspirates, a process often referred as concentration. Ficoll gradient centrifugation is well known art for making bone marrow aspirate concentrates (BMAC). However, this is an open system required special equipment, and time consuming (need at least 45 to 1 hours), required appropriate trained personnel. U.S. Pat. No. 6,981,948 to Pellegrino 2006 disclosed a bone marrow aspiration system in which bone marrow aspirates allowed to pass through chamber containing graft substrates during the collection procedure. The cell retains in the graft material and ready for implantation. The attraction of this design is simple, quick, efficiency, and in the closed system. However, this system fails to separate the richest red blood cells from other cells. U.S. Pat. No. 424,973 to Augustus disclosed a 17.3% glucose gradient centrifuge for concentration of bone marrow aspirates which only need 10 minutes, however, like other gradient centrifuge methods, it is an open system and require special equipment. Recently, a new closed Harvest BMAC system can complete concentration in 10 to 15 minute and available in USA. Recently, Asian described an immuno-isolation to purify MSCs without culture results in 60 times increase in fibroblast CFU as compare those without purification. One aim of the present invention is to provide a clinical usable approach to further enrich MSCs.
In addition to the number of the MSCs, like BMPs, methods of delivery and retention of the MSCs in the site of action is also important for clinical application of MSCs osteogenesis. Many carriers have been tried for delivery of MSCs but most of them are lack of ability to retain MSCs. Thus majority of stem cell migrate away through the blood circulation after implantation decrease its bioavailability. Since MSCs is alive, It significantly limited the materials which can be used to encapsulate the cell in their matrices.
Carrier for stem cells is limited with respect of cell retention, most of the carriers are pre-casted, thus retention of the cell is a problem unless the carrier modified with special affinity molecule. e.g. RGD. In situ polymerized implant has advantage of cell retention, however, heat generation during polymerization and toxic monomers create hostile environment for live cell to survive. Thus, few polymers qualified as in situ polymerizing system for cell delivery (U.S. Pat. No. 6,110,484 to Sierra). Chitosan and fibril sealant are two of few candidates.
Chitosan is a biocompatible nature polymer developed as a delivery vehicle for the peptide (U.S. Pat. No. 2008213354 to Sung). It exhibits thermosensitive property in presence certain inorganic phosphate salts such as glycerol phosphate or tiacalcium phospate, the liquid chitosan solution transformed into a gel at clinically feasible time ranging from 2 to 10 minutes at 37° C. Chitosan have been used extensively for chondral cell transplantation (Marchand, 2009) Chitosan will serve as an alternative for delivery of MSCs In present invention.
Fibrin sealant as delivery system for drugs including growth factors and stem cells is a well known art in the field. Variety applications of fibrin sealant have been nearly exhausted in a world patent (WO/1996/040174, Supplement and un-supplemented tissue sealants, methods of their production and use). Fribrin sealants are two component tissue adhesive systems mimicking natural clot cascade. Two components of fibrin adhesives are stored in sterilized lyophilized powder. The components are reconstituted into liquid form by adding distilled water. As two component mixed together, they polymerized at the site of application into a relatively dense gel. Thrombin in combination of Ca2+ catalyze polymeration of fibrinogen, converting the fibrinogen into fibril polymer. Further, thrombin and Ca2+ activate coagulation factor XIII, which leads to covalent crosslinking of fibrin. The rate of proteolytic degradation of the fibrin polymer clot is decreased and mechanical stability is increased as a result of the covalent crosslinking of the polymer. Presence of fibronectin (U.S. Pat. No. 51,412 to Shane) and hyaluronic acid (U.S. Pat. No. 6,503,527 to whitmore) inhibit the proteolytic degradation, increase the fibril stability.
The fibrin polymer clot is porous with pore size range from 1 to 5 microns in mean diameter. It is too small to allow cell move freely. However, the micro-pore allows easy diffuse of nutrition, growth factor and hormone to maintain normal cellular activity and function. To move in the fibril matrices, cell has to secrete protease or stimulate the other cells such as macrophage to produce protease to degrade the fibril. Thus, fibrin polymer serves as a barrier for the stem cells till degradation of the fibrin polymer and/phagocytosis is complete.
Study using fibrin sealant as carrier for cell transplantation is a well known art. Several studies have used fibrin sealant to delivery chondrocytes to repair the chondrodefect in the knee. The resultant repair does not exhibit hypertrophy shown in cell transplant alone. The beauty of this art is that preparation is in liquid form after injection the fibrin polymerized in situ forming an ideal shape implant predetermined by the defect. Fibrin sealant also attempted to use as carrier for delivery of MSCs stem cell or BMPs to heal bony defect, interestingly, the bone growth in fibrin sealant group is not as robust as compare to other carrier such gelatin. However, fibrin sealant group does show more angiogenesis than other group (review articles). Fibrin sealant as carrier for angiogenesis growth factors exhibited potent agiogenesis potential in animal model and in vitro experiments (Andreas et al Molecular Medicine 2007 and US patent to Shane). Use of the fibrin sealants as carrier for stem cells use for osteogenesis is not fully explored ad is one aim of the present invention.
Bone screws are a basic part of modern internal fixation. They can be used independently, or, in particular types of implants, they can be used together with the implant. The common design of a screw consists of a tip, shaft, thread, and head. A round screw tip requires pretapping, whereas a fluted screw tip is self-tapping. The screw shaft is located between the head and the threaded portion of the screw. The screw thread is defined by its major or outside (thread diameter) and minor or root (shaft diameter) diameters, pitch, lead, and number of threads. The distance between adjacent threads is the pitch.
The 2 basic types of screws available for the variability of bone density are cortical and cancellous screws. Cortical screws are designed for compact diaphyseal bone, whereas cancellous screws are designed for the more trabecular metaphyseal bone. Cortical screws have a smaller major (thread) diameter, decreased pitch, and a shallower thread than cancellous screws. Cancellous screws typically have a larger major (thread) diameter and pitch and a greater difference between major and minor (shaft) diameters in comparison to cortical screws, providing more surface area for bone purchase. These screws are intended for use in metaphyseal fixation, where bone is softer.
A few new designs have made in screws to improve and expand their function in fracture fixation. Biodegradable screw is a very attractive design, since it eliminates possible hardware removal after fracture healing and potential to use it as target drug delivery. Extensive research has been focused in this area. Many drugs including BMPs and biodegradable materials have been tested and or proposed to form a drug delivery screws. Although the system has the capacity to carry significant amount of the drug, which able to sustain release for a long time, toxic reaction to the break down product and weak mechanic strength make the idea not feasible, except few condition where toxic reaction overweight the benefit of the treatment such as cancer (Brode, Integrascience).
Coating of a screw is another new development. In recent studies Mauni demonstrated that hydroxyl apetite (HA) coated screws improve fixation and outcomes in osteoporosis fracture (JOT 2009). Alex use Chitosan coated stainless steel screw to fix the contaminated fracture and demonstrated that gentamicin can be eluted from implant at detectable level for 96 hours. However, the drawback of this system is the dosage limitation during coating.
Porous material serve as a barrier to control the drug delivery is an ancient art for pharmaceutical industry. Author in 1990 have used hollowed polyporous hydroxyl apatite implant to control release of adriamycin, and observed a sustained release for over 45 days in vivo. Recent art of using porous material as out shell and degradable core to for drug delivery demonstrated zero order prolonged stable sustained release (Ca patent 2363902 to Fesrehaie). US Patent NO 2007161985 to Demakas et al disclosed a "porous screw" which has a channel inside had at least one pore on lateral wall, the pore is filled with PMMA and BMPs to allow bone structure to grow into the "porous screw". However, BMP release from the PMMA is limited. US patent 20090192552 disclosed a special screw with expansible sleeve to anchor the bone while a hollow core used for injection of bone cement to enforce the fixation. The above idea is quite interesting. However, they are not suitable for delivery of stem cells, the other important component for bone formation and scope of clinical application is not clearly defined except spine surgery. Since bioactive agents release from above invention is limited and diffuse through full length of the screw, they may help bone in-growth to the implant at sub-cellular level to create biological fixation. Thus, this screw may be suitable for position screw fixation.
Since sustained high local concentration is critical for osteoinductive activity of BMPs and stem cell. A hollowed poly-porous screw with define chamber filling with biodegradable protein core is used in present invention as a barrier for targeted delivery and controlled release of BMP and stem cell to the injury site to facilitate tissue healing. Targeted delivery achieved to by using this new screw for fixation as lag screw, interference screw, and pedicle screw.


A three-dimensional microporous polymer network material, or monolith, cast-to-shape in a microchannel. The polymer monolith, produced by a phase separation process, is capable of trapping and retaining charged protein species from a mixture of charged and uncharged species under the influence of an applied electric field. The retained charged protein species are released from the porous polymer monolith by a pressure driven flow in the substantial absence of the electric field. The pressure driven flow is independent of direction and thus neither means to reverse fluid flow nor a multi-directional flow field is required, a single flow through the porous polymer monolith can be employed, in contrast to prior art systems. The monolithic polymer material produced by the invention can function as a chromatographic medium. Moreover, by virtue of its ability to retain charged protein species and quantitatively release the retained species the porous polymer monolith can serve as a means for concentrating charged protein species from, for example, a dilute solution.

The present invention is directed generally to a porous polymer medium, produced by photopolymerization, for separating and concentrating charged protein species from a carrier fluid that can contain both charged and uncharged species.
It is frequently the case that it is desired to analyze molecular species, and charged protein species in particular, that are present in very low concentration either because the sample itself is very small or dilute or because the species of interest is present as a consequence of prior chemical processing and is thus at very low concentration. Moreover, these molecular species can be charged and being in the presence of uncharged molecules present further difficulty in analysis or separation.
Prior art provides a plurality of methods for concentrating molecular species from solution. However, there are numerous problems associated with these prior methods, such as the need for specialized column packing, the need for specialized solvents or buffer solutions, the need to change solvents or buffer solutions in order to elute concentrated molecular species, the need to change flow direction or flow conditions between the steps of retaining and eluting species, and the inability to either separate charged and uncharged molecular species or effect an efficient separation.
Zare et al. (Anal. Chem., 73, 3921-3926, 5539-5543, 5557-5563, November 2001) describe porous sol-gel monoliths that overcome some of the problems inherent in prior art column packing materials. These monoliths, useful for capillary electrochromatography, wherein neutral species are to be separated, can be prepared by a one-step process but their pore structure is uncontrolled.
Palm et al., Anal. Chem., 69, 4499-4507, 1997, have described a one-step process for in situ preparation of macroporous polyacrylamide gel matrices for capillary electrochromatography that can be purged by the use of electroosmotic flow (EOF). While the solvent can be purged from these formulations by the use of EOF, the gel matrices have limited structural stability in useful chromatographic solvents such as acetonitrile. Moreover, polyacrylamide gels are highly swelled gels of low polymer content that rely on the solvent for their structure. Thus, these gels suffer from the draw back that they cannot be dehydrated without losing their structure.
A method for separating and concentrating charged species from uncharged or neutral species regardless of size differential has been disclosed by Singh et al. in U.S. patent application Ser. No. 09/256,586 entitled Electrokinetic Concentration of Charged Molecules, incorporated herein in its entirety. The method uses reversible electric field induced retention of charged species, that can include molecules and molecular aggregates such as dimers, polymers, multimers, colloids, micelles, and liposomes, in volumes and on surfaces of porous materials. The retained charged species are subsequently quantitatively removed from the porous material by a pressure driven flow that passes through the retention volume and is independent of direction thus, a multi-directional flow field is not required. Uncharged species pass through the system unimpeded thus effecting a complete separation of charged and uncharged species and making possible concentration factors greater than 1000-fold.
Singh et al. have found that the phenomenon of retention or trapping of charged molecules under the influence of an electric field occurs neither in an open capillary or channel nor in a capillary or channel packed with a stationary phase consisting of nonporous silica or polymer particles having a diameter of 1 xcexcm or larger. Consequently, the porous stationary phase in Singh et al. has certain required properties. First, it must be capable of supporting electroosmotic flow. Second, the porous particulate material must have certain physical characteristics in order to effectively trap and retain charged particles. Silica particles having a diameter of about 1.5 to 20 xcexcm and containing pores having a diameter of about 50 to 500 xc3x85 are preferred as a stationary phase material and silica particles having a diameter of about 5 xcexcm and containing pores having a diameter of about 300 xc3x85 are particularly preferred.
While a porous particulate stationary phase has been shown to effectively trap and retain charged particles, these stationary phases are very difficult to fabricate, particularly in microchannels. In particular, the need to retain the particulate materials within the chromatography column requires fabrication of porous frits of controlled pore size over a significant length and high mechanical stability. This requirement presents a significant challenge to the use of a porous particulate stationary phase for separation of charged from uncharged species.
Accordingly, the present invention is directed to a three-dimensional microporous polymer network material, or monolith, that can be cast-to-shape in a microchannel. The polymer monolith is fabricated with structural characteristics that provide the capability for trapping and retaining charged protein species from a mixture of charged and uncharged species under the influence of an electric field. The retained charged particles are released by application of a pressure gradient in the substantial absence of an electric field.
Application of an axial voltage differential to a solution in contact with column or microchannel containing a stationary phase, wherein the stationary phase is the porous polymer monolith of the present invention, causes the solution, that can contain both charged and uncharged protein species to move through the column under the influence of electrophoretic and/or electroosmotic forces. Neutral or uncharged species contained in the solution completely traverse the length of the column while the charged protein species, that can be smaller or bigger than the neutral species, are retained on the porous polymer monolith. Retention or trapping of charged species only occurs in the presence of a porous stationary phase and while an electric field is applied along the solution flow path.
Charged protein species retained on the porous polymer monolith are removed by application of a pressure differential to the packed column. While it is preferred that the pressure differential be applied in the substantial absence of an electric field, it has been found that by adjusting the relationship between applied pressure and voltage such that the pressure-driven flow is significantly greater than the electric field induced transport, the charged protein species can be eluted from the porous stationary phase while a voltage is being applied to the column. Further, the pressure-driven flow that removes the retained charged species from the porous matrix is independent of direction and thus neither means to reverse fluid flow nor a multi-directional flow field is required. Consequently, a single flow through the porous polymer monolith can be employed to separate charged from uncharged protein species in contrast to prior art systems.
The polymer monolith is produced by a phase separation process. Phase separation occurs during polymerization of a monomer or monomer mixture dissolved in a solvent yielding a polymer-rich and a solvent-rich phase. The solvent-rich phase produces the micropores through which liquids flow during a separation. The parameters of the phase separation process are established such that the solvent-rich phase forms a majority of pores in the range of about 200 nm-10 xcexcm. The lower limit (≈200 nm) is established to provide efficient hydrodynamic flow of a liquid phase during either pressure-driven or electric field-driven flow. The upper limit (≈10 xcexcm) must be small enough for interaction by diffusion between mobile and stationary phases. The polymer-rich phase becomes a porous monolithic backbone that is formulated to contain a substantial portion of an alkoxy-substituted metal, such as Si, Ti, or Zr, as a protected functionality. Hydrolysis of the alkoxy functionality provides the charged groups necessary for electric field-driven flow. Consequently, at least about 20 vol % of the monomers contain an alkoxy protected metal functionality.
Extensive crosslinking allows the porous polymer monoliths to achieve high molecular weights and, in contrast to prior art porous polymer materials, imparts a high structural stability such that the polymer monolith resists swelling and/or dissolution in the presence of a wide variety of solvents and during subsequent hydrolysis. In the present invention at least about 20 vol % of the monomer is present as a crosslinker in order to provide a rigid matrix such that hydrolysis of the alkoxymetal functionality will not collapse the structure. If the monolith is to be employed as a separations medium in reverse phase chromatography applications, it is desirable to have at least about 25 vol % of the monomer containing a hydrophobic group such as alkyl, aryl, or substituted versions thereof.
Polymerization is initiated by adding a polymerization initiator and exposing the solvent/monomer solution to radiation whose wavelength is matched to the absorbance of the free radical polymerization initiator. Following the phase separation step and after the three-dimensional polymer structure has been established, the alkoxy protecting groups are hydrolyzed. This converts a portion of the monomer to a porous metal oxide structure that cannot collapse despite the large localized loss of mass because the bulk structure of the monolith has been defined by the initial crosslinked vinyl polymerization step. In this way, the polymer of the invention differentiates from sol/gel produced polymer materials. The charge on the metal oxide, and consequently the zeta potential, is controlled by pH, i.e., silica is negative at pHxe2x89xa74 and titania is positive at pHxe2x89xa66. After hydrolysis, the solution remaining in the pores of the monolith is exchanged for an appropriate running buffer.
In addition to separating charged from uncharged protein species, the monolithic polymer material produced by the invention has been found to function as a chromatographic medium. The inventors have found that when a plurality of retained charged protein analytes are eluted from the polymer stationary phase by application of a pressure gradient, a chromatographic peak relating to each of the plurality may be observed.

Cast-to-shape electrokinetic trapping medium


A tire comprises a tread portion 2. The tread portion 2 is provided with at least one main groove 3 extending continuously in a tire circumferential direction. A first groove wall 10, which is one of groove walls of the main groove 3, is provided with at least one first recessed portion 11 recessed outwardly in a groove width direction from a corresponding one of groove edges 6 of the main groove on a ground contacting surface of the tread portion 2. In the first recessed portion 11, a recess amount from the corresponding one of the groove edges 6 gradually decreases toward both sides in the tire circumferential direction from a deepest portion 15 recessed most outwardly in the groove width direction.

For example, Japanese Unexamined Patent Application Publication No. 2016-124442 has proposed a tire in which a tread portion is provided with a main groove. One of groove walls of the main groove is inclined toward an outer side of the main groove with respect to a normal line of a ground contacting surface of the tread portion from a side of the ground contacting surface to a side of a groove bottom thereof. The main groove having the groove walls configured as such is advantageous for maintaining drainage performance of the tread portion after wearing.
However, parts on a side of groove edges of land regions divided by the main groove tend to collapse toward a groove center of the main groove with a connecting portion between the groove wall and a groove bottom portion as a fulcrum during running. Thereby, the above tire has a room for improvement with respect to steering stability on a dry road surface.


A reciprocal motion wind energy harvesting device has a first vane carrier assembly and a second vane carrier assembly, which are supported by and rotate about a central shaft. The vane carrier assemblies support pluralities of vanes to receive wind force. The vanes are configured to be rotatable in order to produce opposing and reciprocating motion of the lever arm assemblies. The lever arm assemblies are operatively connected to a generator in order to convert the wind force received by the vanes into energy.

In the present times, individuals are always looking for ways to innovate wind powered technologies. Conventional systems known in the art, such as wind-turbines are often complex and expensive to develop/construct. Additionally, wind-turbines often operate at an optimal height that may be unsuitable for urban environments. Further, wind turbines are susceptible to damage due to the fact that they cannot be strutted along the mast.
The present invention aims to solve these problems. The present invention utilizes a self-oscillating motion/mechanism that is constructed out of cost effective, lightweight, and simple pneumatic/electrical parts. Additionally, the present invention can be deployed from the grounds-up, such that it inflates itself up to an optimal height. The present invention can also be lifted as a high-flying "self-oscillating" kite, such that the chassis of the present invention acts as lift generating air foils. Further, the present invention can be hoisted from the optimal height, due to horizontal profile of the self-oscillating motion/mechanism. In another embodiment, the present invention can be adapted to accept undercurrents associative with rivers and/or ocean currents.
Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Additional advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the detailed description of the invention section. Further benefits and advantages of the embodiments of the invention will become apparent from consideration of the following detailed description given with reference to the accompanying drawings, which specify and show preferred embodiments of the present invention.

Reciprocal motion wind energy harvesting device


A solution-type moisture indicating ink to be printed on a substrate and change color at a preselected ambient moisture. The indicator ink includes a solvent carrier system, a moisture indicating substance which changes color under the influence of moisture, and a resin system as a binder to hold the moisture indicating substance to the substrate as well as a film forming and viscosity adjusting agent.

(1) Field of the Invention
The present invention relates to inks which include an ingredient which changes color in response to different ambient moisture levels, and more particularly to a solution-type moisture indicating ink wherein the ink ingredients are in solution and which can be printed at a high rate upon the substrate.
(2) Discussion of the Prior Art
Various inks or coating which change color are known per se. Examples of such heretofore known and their uses are disclosed in the following United States Patents.
U.S. Pat. No. 650,901, issued on June 5, 1900 to Ernest Kretschmann.
U.S. Pat. No. 2,228,033, issued on Jan. 7, 1941 to Thomas A. Martone.
U.S. Pat. No. 3,216,802, issued on Nov. 9, 1965 to Charles J. Smith.
U.S. Pat. No. 3,360,339, issued on Dec. 26, 1967 to Martin Edenbauum.
U.S. Pat. No. 3,499,316, issued on Mar. 10, 1970 to W. O. Krause.
U.S. Pat. No. 3,548,639, issued on Dec. 22, 1970 to W. O. Krause.
U.S. Pat. No. 3,881,873, issued on May 6, 1975 to Iris B. Klowden.
U.S. Pat. No. 4,643,122, issued on Feb. 17, 1987 to Paul G. Seybold.
U.S. Pat. No. 650,901 teaches an ink consisting of a solution of the halide salts of cobalt, glycerin, gum arabic and water. A paper is coated with this solution. This ink is developed using a developing ink of resorcinol and paratoluidine, water, and sulfuric acid.
U.S. Pat. No. 2,228,033 teaches an ink which is normally invisible when printed on fabrics and paper, but becomes visible when wetted with a solution. This patent more particularly teaches cellulose nitrate or acetate or various gums and solvents such as amyl alcohol, butyl alcohol, their esters, and, glycol ethers. The ink also includes a colorless gum or resin or cellulose derivative in a volatile water soluble monohydric alcohol, preferably, ethyl cellulose in methyl or ethyl alcohol. When the ink is printed on paper, it is invisible, and becomes visible when wetted by water. The ink consists of a volatile alcohol of the group consisting of methyl and ethyl alcohol, and alcohol soluble cellulose ether.
U.S. Pat. No. 3,216,802 teaches a reagent for determining the moisture content of paper. The reagent is a solution of cobaltous chloride in a non-aqueous volatile solvent which is placed in contact with a fibrous web (such as paper) and the solvent allowed to evaporate so that the residue of cobaltous chloride remaining on the fibrous web will undergo a color change which is directly related to the moisture content of the fibrous web. The solvent may be methanol, ethanol, acetone or mixtures thereof.
U.S. Pat. No. 3,360,339 teaches a temperature indicating ink which consists of a solution of copper sulfite and a film such as methyl isobutyl ketone. The ink changes color when exposed to moisture above 250.degree. F.
U.S. Pat. No. 3,499,316 teaches a moisture indicating material applied to a mat of inert fibers or paper and discloses the use of cobaltous bromide, magnesium chloride, calcium chloride, aluminum chloride and cobalt chloride as moisture indicators. The indicator of this ink uses a dual salt such as a cobaltous bromide and a bromide salt of zinc, cadmium or mercury as the moisture indicator which changes color.
U.S. Pat. No. 3,548,639 is related to U.S. Pat. No. 3,499,316 and teaches a dual salt moisture indicator of cobaltous bromide and barium chloride or magnesium chloride.
U.S. Pat. No. 3,881,873 teaches a moisture indicator of an aqueous solution of cobaltous chloride.
While the above patents discuss various moisture indicating inks which change color using cobalt chloride as the color changing ingredient or moisture indicator, alcohol as a carrier, and cellulose derivatives as a binder, none of these inks have been found suitable for use as a printing ink on commercial printing or coating equipment at production speeds. Furthermore, none of the heretofore color indicating inks known to us can be applied to a hydrophobic surface such as a glossy or top coated paper.

Moisture indicating ink and package having same


Various modular implants and modular implant systems are disclosed herein, as are methods of implanting the same. The modular implant systems can include modular implants that are stacked on each other to define a modular implant system, which in an example can be used to replace or augment a void in bone. The modular implants can interact with an intramedullary implant to, for instance, assist with a fusion procedure.

Intramedullary implants are used in various contexts, including to repair fractures or to achieve joint fusion (i.e., arthrodesis). In the case of arthrodesis, it is frequently necessary to apply compression across one (1) or more joints to bring the adjoining bones of the joint into apposition, and then fix the adjoining bones so that fusion can occur across the joint site. An intramedullary implant can be used to achieve fixation of the adjoining bones of the joint after compression and secure the bones in position to allow fusion to occur.
In some cases, bone augments can also be used with intramedullary implants to replace and/or augment a particular bone. This can be the case in instances where, for example, bone is diseased and/or some trauma has occurred to the bone and the bone needs to be replaced or augmented. U.S. Pat. No. 9,308,031 ("the '031 patent") discloses various intramedullary devices that are used for ankle fusion, as an example. The '031 patent is hereby incorporated by reference herein and is referred to below, in some instances. When bone augments are used with intramedullary implants, it is desirable to ensure that the bone augment cooperates with the intramedullary device and also that proper bone growth and/or fusion occurs when using the augment.
The present disclosure provides intramedullary implants, instruments, and methods that work in cooperation with bone augments to allow surgeons to conduct surgical repairs in a more effective manner, as described in more detail below.


An interactive game includes a playing surface defining playing positions, a display operable to display a visual game image on the playing surface, a sensor operable to optically detect a playing piece placed on the playing surface, and a game controller connected to the sensor and the display. The game controller creates the game image on the display and alters the game image in response to a location or orientation of the playing piece on the playing surface.

This invention relates to interactive games.
Interactive games include games that respond to the input and actions of a game player. For example, in an interactive game of chess, the movement of a playing piece by one player may cause a computer acting as an opponent to respond by moving another playing piece. Interactive games also may provide visual and audio effects based on the state of the game or in response to input from the players.
In one general aspect, an interactive game includes a playing surface defining playing positions, a display operable to display a visual game image on the playing surface, a sensor operable to optically detect a playing piece placed on the playing surface, and a game controller connected to receive information from the sensor, configured to generate signals for use in creating the game image using the information from the sensor, and connected to the display to provide the signals to the display. The game controller causes the display to after the game image in response to a location or orientation of a playing piece on the playing surface.
Implementations may include one or more of the following features. For example, the sensor may be operable to optically detect a foreign object in its field of vision and the game controller may alter the game image upon detection of the foreign object.
The interactive game may include a frame secured to the playing surface. The frame may be attached to a table, or may include a table.
The interactive game may include playing pieces that may be of different types. The playing pieces may include playing cards, tokens, vehicles, or figurines.
The display may be implemented using, for example, a projector, a cathode ray tube, or a liquid crystal display. The sensor may include, for example, a digital camera, a laser, a bar code reader, or a tag reader. In some implementations, a tag writer may be employed to update the status of game tokens.
The game controller may be a computer configured to use an optical character recognition system or machine vision technology. The interactive game may include a speaker and/or a microphone connected to the game controller. The game controller may be configured to emit sound in response to the location or orientation of a playing piece on the playing surface. Additionally, or alternatively, by using the microphone, the game controller may alter the game image in response to a sound. The game controller also may be configured to send a control signal to another device in response to a location or orientation of the playing piece on the playing surface. For example, the game controller may send the control signal to another toy, to a computer, or to audio equipment. The game controller also may be configured as an artificially intelligent opponent to a human player.
The interactive game provides an engrossing, interactive experience for one or more players. By altering the game image upon movement of a playing piece to another position, and by other interactive features, the players may stay more involved and find the game experience more enjoyable.
Implementations of the above features may include methods, systems and/or computer software. Other features and advantages will be apparent from the description, the drawings, and the claims.


A method is described for producing a prepreg formed by applying a matrix resin to a reinforcing fiber sheet, wherein the method can effect continuous running without clogging due to generated fuzz even at a high running speed and effect efficient impregnation of the reinforcing fiber sheet with a matrix resin. A method of producing a prepreg includes allowing a reinforcing fiber sheet to pass substantially vertically downward through the inside of a coating section storing a matrix resin to obtain a matrix resin-impregnated reinforcing fiber sheet in which the matrix resin is applied to the reinforcing fiber sheet and at least heating the matrix resin-impregnated reinforcing fiber sheet, wherein the coating section includes a liquid pool and a narrowed section which are in communication with each other, wherein the liquid pool has a portion whose cross-sectional area decreases continuously along a running direction of the reinforcing fiber sheet.

Fiber reinforced composite materials (FRP) in which a matrix resin containing a thermoplastic resin or a thermosetting resin is reinforced with a reinforcing fiber are used in various fields such as aerospace materials, automobile materials, industrial materials, pressure vessels, construction materials, housings, medical applications, and sports applications. Carbon fiber reinforced materials (CFRP) are widely and suitably used particularly in cases where high mechanical property and lightness are required. On the other hand, in cases where cost has priority over a mechanical property and lightness, glass fiber reinforced composite materials (GFRP) are used. FRP is obtained by impregnating a reinforcing fiber bundle with a matrix resin to obtain an intermediate base material, which is laminated and formed, and further thermally cured if a thermosetting resin is used, members composed of FRP are then produced. In the above-mentioned applications, planar objects or objects formed by folding planar objects are often used, and two-dimensional sheet-like objects are more widely used as intermediate base materials of FRP than one-dimensional strands and roving-like objects, from the viewpoint of lamination efficiency and moldability achieved in producing such members.
In addition, an attempt to enhance production efficiency for members composed of FRP has recently promoted the mechanization and automation of lamination of sheet-like intermediate base materials, and here, narrow tape-like intermediate base materials are suitably used. Narrow tape-like intermediate base materials can be obtained by slitting broad sheet-like intermediate base materials into tapes having a desired width or impregnating a narrow reinforcing fiber sheet directly with matrix resins.
As two-dimensional sheet-like intermediate base materials, prepregs obtained by impregnating reinforcing fiber sheets with matrix resins are widely used. Examples of reinforcing fiber sheets used for prepregs include UD base materials obtained in sheet-like form by arranging reinforcing fibers unidirectionally and reinforcing fiber fabrics that are woven fabrics obtained by arranging reinforcing fibers multidirectionally. UD base materials are often used particularly in cases where the mechanical property has priority.
A hot-melt process that is one of the methods of producing prepregs is a method in which a matrix resin is melted and then applied onto release sheets, a laminated structure is produced in which a reinforcing fiber sheet is sandwiched between the matrix resin sheets at the upper side and lower side of the reinforcing fiber sheet, and then, the inside of the reinforcing fiber sheet is impregnated with the matrix resin by heat and pressure. There is a problem in that this method has many steps, cannot increase the production speed, and is costly.
For more efficient impregnation, for example, Patent Literature 1 has made a proposition. This is a method in which glass fiber is melted and spun, and the resulting spinning bundled in strand form or roving form is allowed to pass through a liquid pool filled with a thermoplastic resin and having a conical flow path.
As another example, Patent Literature 2 describes a method in which a coating film is formed on both faces of a sheet-like object simultaneously, but this is a method in which a sheet-like object is allowed to pass through a web-guide and coated using a pipe type doctor blade in order to prevent fluctuation of the sheet-like object in the formation of the coating film.
As a method of producing strip-like prepreg using a thermoplastic resin, a horizontal type pultrusion method is known in which a strip-like reinforcing fiber bundle is conveyed in the horizontal direction (longitudinal direction) and is allowed to pass through a die, where the strip-like reinforcing fiber bundle is provided and impregnated with a thermoplastic resin (Patent Literature 3 and Patent Literature 4). According to Patent Literature 3, a tape-like reinforcing fiber is allowed to pass through a crosshead (in FIG. 2 in Patent Literature 3), and the tape-like reinforcing fiber bundle is provided with a resin immediately before a linear die in the crosshead. Patent Literature 4 explains that a plurality of strip-like reinforcing fiber bundles are separately introduced into a die filled with molten thermoplastic resin, opened, impregnated, and laminated using a fixed guide (for example, a squeeze bar), and finally withdrawn from the die as one sheet of prepreg.

Production method for prepreg, prepreg tape, and fiber reinforced composite material, and prepreg production device


A fuel injector 10 may comprise a valve body 14 having a fuel path, a valve seat 23 fixed to a downstream end of the valve body, and a valve 25 that opens and closes a fuel injection hole of the valve seat 23. The valve may be housed within the valve body in a manner allowing sliding. An armature 31 may be attached to an upstream end of the valve 25, and a valve closing element 32 may be attached to a downstream end of the valve 25. A core 21 may be disposed at an upstream side of the armature 31. A downstream end surface of the core 21 faces an upstream end surface of the armature 31. When the valve 25 opens the fuel injection hole, the downstream end surface of the core 21 makes contact with the upstream end surface of the armature 31. A non-magnetic ring 20 may be disposed at an outer circumference side of the armature 31 and the core 21. The non-magnetic ring 20 may extend as far as an upstream side of the solenoid coil 18, and the solenoid coil 18 may be wound directly around an outer circumference of the non-magnetic ring 20.

1. Field of the Invention
The present invention relates to a fuel injector. Specifically, the present invention relates to a technique for reducing the diameter of a fuel injector.
2. Background of the Invention
FIG. 8 shows a longitudinal section of a conventional fuel injector 100. The fuel injector 100 comprises a valve body 116, a core 122, a valve seat 112, a valve 110, a spring 120, and a solenoid coil 106. The valve body 116 has a fuel path. The valve seat 112 is attached to a downstream end of the valve body 116, and a fuel injection hole 112a is formed in the valve seat 112. The valve 110 is housed within the valve body 116, and can slide between an open position and a closed position. The valve comprises a shaft 109, an armature 108, and a ball 114. The armature 108 is attached to an upstream end of the shaft 109, and the ball 114 is attached to a downstream end of the shaft 109. The fuel injection hole 112a is open when the valve 110 is in the open position, and the fuel injection hole 112a is closed when the valve 110 is in the closed position. The spring 120 applies a biasing force on the valve 110, wherein the biasing force pushes the valve 110 in the closed position. The core 122 is disposed upstream from the armature 108. When the valve 110 is in the open position, an upstream end surface of the armature 108 makes contact with a downstream end surface of the core 122. When the valve 110 is in the closed position, the upstream end surface of the armature 108 is separated from the downstream end surface of the core 122. A non-magnetic ring 104 is disposed at an outer circumference side of the armature 108 and the core 122. The non-magnetic ring 104 extends from an upstream side of the armature 108 to a downstream side of the core 122. A downstream end of the non-magnetic ring 104 is fixed to the valve body 116, and an upstream end of the non-magnetic ring 104 is fixed to the core 122. A resin bobbin 102 is formed at an outer circumference of the non-magnetic ring 104 and the core 122, and the solenoid coil 106 is wound around the bobbin 102. An upper body 118 is disposed at an outer side of the solenoid coil 106, and a downstream end of this upper body 118 is connected with the valve body 116. An upstream end of the upper body 118 is connected with the core 122.
Pressurized fuel is supplied to the fuel injector 100 from fuel supply line (not shown). When the solenoid coil 106 is excited, a magnetic path is formed from the upper body 118, the valve body 116, the armature 108, and the core 122. At this juncture, the non-magnetic ring 104 prevents magnetic flux from short-circuiting from the valve body 116 to the core 122. When the magnetic path has been formed, the armature 108 is attracted by magnetic force, and the valve 110 retreats towards the core 122 side (towards a posterior end side) in resistance to biasing force of the spring 120. The fuel is thus injected from the fuel injection hole 112a. When the excitement of the solenoid coil 106 is halted, the biasing force of the spring 120 causes the valve 110 to advance towards the valve seat 112, and the injection of fuel is suspended.


A bellows-type cover into which a clamping member is adapted to be securely integrated to form a preassembled unit; the groove-shaped recess near one end of the bellows-type cover adapted to receive the clamping member has a two-tier positioning arrangement with a radially inward, circumferentially extending bottom surface for engagement by the clamping member when fully tightened and with a temporary bottom for the clamping member to provide a releasable self-retaining support for the closed, but not yet fully tightened clamping member at a radial distance between the bottom surface and the radially outer limit of the recess.

Flexible or elastic bellows-type covers usually of accordion-like construction, such as axle boots for universal joints or for drive shafts must be carefully sealed to protect the lubricant. Such bellows-type covers have been used extensively in the automotive industry, for example, with front-wheel drive vehicles. They are normally fastened to the axle stub shafts by means of hose clamps or shrinkable compression rings. A need exists at present on the part of manufacturers of universal joint shafts or drive shafts for bellows-type covers in which clamping members in the form of "Oetiker" hose clamps or "Oetiker" shrinkable compression rings are already integrated into the bellows-type covers. In other words, the manufacturers desire a product in which the clamping members are already integrated at or in the bellows-type covers which favors the automatic assembly of the universal joint or drive shafts in that the bellows-type covers provided with integrated clamping members are available as preassembled parts so as to avoid the need for mounting the clamping members on the bellows-type covers only at the final assembly as is the case today.

Bellows-type cover with integrated clamping member

Hans Detiker Maschinen-und Apparate fabrik


A system includes a computer having a processor and a memory storing instructions executable by the processor to determine a braking distance based on a gap distance between a primary vehicle and a second vehicle in an adjacent lane, and based on a speed of the second vehicle in the adjacent lane. The instructions include instructions to actuate a braking system of the primary vehicle when the primary vehicle is the braking distance from a third vehicle in a same lane as the primary vehicle.

Autonomous and partially autonomous vehicles can perform operations such as setting or maintaining a vehicle velocity, following a particular route, and maintaining a specified distance from other vehicles. A vehicle velocity can be set and maintained according to user input and/or based on a velocity and/or relative position of a reference vehicle, typically an immediately preceding vehicle.


In some embodiments, methods and systems are provided that permit a customer to purchase products from a retailer and elect an option for a friend or family member of the customer to pick up the ordered products from the retail facility of the retailer associated with the geographic location of the customer. If the friend or family member of the customer agrees to pick up the products for the customer, and if the customer agrees to have the selected friend or family member of the customer pick up the products for the customer, the friend or family member is allowed to pick up the products at the retail facility associated with the geographic location of the customer. The customer is then allowed to either pick up the products from such a friend or family member or the friend or family member may deliver the products to the customer.

Customers often purchase products from retailers over the internet. Generally, the products purchased by a customer are delivered to an address provided by the customer. Some customers elect to pick up the products they order from a retail facility of the retailer. Delivery of products to an address provided by the customer is associated with extra costs for the retailer and for the customer. In addition, products delivered to a home address and left on the property of the customer when the customer is not home (e.g., at work) may be stolen and/or damaged by 3rd parties. On the other hand, picking up products at the retail facility of the retailer may be undesirable for customers because it is time consuming and/or inconvenient for the customers.
Elements in the figures are illustrated for simplicity and clarity and have not been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. Certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. The terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein.

System and method for facilitating pick up of products ordered by a customer by a friend or family member of the customer


The present disclosure relates to a semiconductor package that may include a substrate, an interposer coupled to the substrate, a shield frame including at least one frame recess and at least one opening positioned over the interposer, a conductive shield layer on the shield frame, and a plurality of components coupled to the interposer.

In typical 2.5 D/3D stacked die packaging systems, a stacked package includes a silicon interposer wherein power delivery decoupling capacitors are disposed far apart from stacked integrated circuit devices on a package substrate landside. Such designs often result in escalated power supply noise jitter and performance degradations.
Current solutions to mitigate extensive power loop inductance and associated signaling jitter include increased package and/or printed circuit board decoupling capacitors to suppress the power supply noise. However, increased decoupling passive components, e.g., capacitors, consume additional package and/or platform real estate, thereby inhibiting device miniaturization.
Further, for platform miniaturization of heterogeneous devices, communication devices such as radio frequency integrated circuit (RFIC) and WIFI devices are arranged adjacent core processing devices, e.g., a central processing unit (CPU) or a graphic processing unit (GPU). Such designs often result in electromagnetic interference (EMI) and/or radio-frequency interference (RFI), collectively referred to as EMI, which can affect the operation of electronic circuitry.
Current solutions to mitigate EMI among devices in a computing system include increased device-to-device spacing, application of flexible EMI shield, or discrete package assembly for the communication devices. However, increased device-to-device spacing to circumvent EMI leads to lossy interconnects ascribed to increased conductor length and associated conductor resistance and skin-effects, thereby limiting channel transmission bandwidth.

Electrical shield for stacked heterogeneous device integration


A method is described for controlling load variations in a gas turbine. The method comprises reducing the flow of gaseous fuel entering the combustor to a predefined minimum value, if an increase is observed in the rotation regime of said turbine above a predefined maximum value and a total reduction in the load, activating a selective feeding sequence of the burners if the turbine is operating in normal functioning or premixed flame mode, modifying the angulation of the adjustable stator vanes, in order to reduce the speed rate of the compressor, and opening one or more anti-surge valves and one or more overboard bleeds, in order to reduce the air flow at the inlet of the combustor.

1. Field
The exemplary embodiments generally relate to a method for controlling the load variations, in particular load reductions, in a gas turbine.
2. Brief Description of Related Developments
The use of gas turbines normally consisting of a multiphase compressor, in which air sucked from the outside is compressed, a combustor, in which the combustion takes place of gaseous fuel added to the compressed air, and a turbine or expander, in which the gases coming from the combustor are expanded, is known for the production of electric energy. The turbine is therefore capable of generating mechanical energy which can be exploited for driving operating machines or for charging electric generators, such as for example, one or more alternators.
A gas turbine destined for the production of electric energy must consequently be able to face sudden disconnections from the electric supply, which can be due, for example, to particular circumstances or inefficiency which can arise in the electric supply. In a situation of this kind, the turbine must be brought to an anomalous but stabile functioning condition, in which the nominal rotation regime is reached, but the alternator does not supply power (a functioning condition called "full speed no load"), until the voltage is re-established in the outside electric supply to restart the service, i.e. reconnection with the electric supply.
During this disconnection phase with the supply, a so-called "load rejection" procedure must be activated as soon as possible, to immediately reduce the power and rotation regime of the turbine to a sufficiently low value so that at least one alternator can self-charge the auxiliary services of the machine or plant to which it is connected. The load rejection procedure is particularly critical for a gas turbine of the double shaft type, as the mechanical inertia of the turbine itself is extremely low and the corrective actions for preventing reaching an excessive rotation regime must be rapid and effective.

Method for controlling the load variations in a gas turbine


Disclosed herein is a magneto-optical medium of the type that information recorded therein is reproduced by displacing a domain wall, the medium comprises a substrate, and a magnetic layer provided on the substrate, which permits domain wall displacement, wherein the surface roughness Ra of the substrate is 1.2 nm or smaller.

1. Field of the Invention
The present invention relates to a magneto-optical medium capable of ultrahigh-density recording, which utilizes domain wall displacement upon reproduction.
2. Related Background Art
In recent years, attention has been attracted to magneto-optical disks as rewritable high-density recording media, and there has been a strong demand for further enhancing the recording density of these magneto-optical media to provide them as recording media having a greater capacity. The linear recording density of an optical disk greatly depends on the laser wavelength and the numerical aperture NA of an objective lens of a reproducing optical system, and the detectable range of the spatial frequency upon reproduction of a signal is limited to about NA/.lambda.. Therefore, for actually achieving higher recording density with a conventional optical disk, it is necessary to shorten the laser wavelength .lambda. or enlarge the numerical aperture NA of the objective lens in the reproducing optical system. However, the improvements in the laser wavelength .lambda. and the numerical aperture NA of the objective lens are limited naturally. Therefore, some techniques that the constitution and reading method of a recording medium are devises to improve the recording density have been proposed.
For example, in Japanese Patent Application Laid-Open No. 6-290496, the present applicant previously proposed a magneto-optical medium, a reproducing method and apparatus therefor, by which signals of frequency of less than the optical diffraction limit of an optical system can be reproduced at a high speed without decreasing the amplitude of reproduction signals. When a temperature distribution is formed on a displacement layer of a magneto-optical medium by a heating means such as a light beam, a distribution is formed in the domain wall energy density of the displacement layer as described in this publication. Therefore, a domain wall can be displaced momentarily in a direction low in domain wall energy. As a result, the amplitude of a reproduction signal always becomes fixed and maximum irrespective of the interval (i.e., the length of a record pit) between domain walls of a magnetic domain recorded. Namely, the inevitable reduction in reproduction output attendant on the improvement of linear recording density is greatly improved, so that still higher-density recording becomes feasible.
According to Japanese Patent Application Laid-Open No. 6-290496, the domain wall displacement is a phenomenon occurred in the same track (in a direction of the track), in which it is necessary that a magnetic layer be divided (i.e., magnetically separated among) into tracks. As a method for producing such open magnetic domains (divided domain walls), Japanese Patent Application Laid-Open No. 6-290496 proposes a method of using a rectangularly and deeply grooved substrate or a method of annealing groove portions of a substrate by irradiating them with a laser beam to magnetically modify them. However, the rectangularly and deeply grooved substrate has involved a problem of transferability that the bottom portions of rectangular grooves in a stamper cannot be finely transferred when transferring the pattern of the stamper upon stamping, and so the land portions of the substrate become a U-shaped section, resulting a failure to achieve a sufficient dividing effect. On the other hand, the annealing treatment requires to treat the substrate at a high temperature by irradiation of a laser beam of high power, or the like. The annealing by the laser beam of high power has involved a problem that since the area of portions deteriorated in magnetic property (modified in the magnetic layer) also spread outside tracks depending on the temperature distribution of the laser beam, the area of the magnetic layer, which can be substantially used as an information data division, is narrowed, and so a track density is decreased.

Magneto-optical medium utilizing domain wall displacement


A drive system for releasably interconnecting a motor shaft of a rotary hand held power tool and an input shaft of an attachment device that is mounted thereon includes an elongated flexible drive shaft and an elongated output shaft. The flexible drive shaft is connected to the input shaft of the attachment device and includes an outer end portion with a non-circular cross-section configured to engage a complementarily shaped cavity of an output shaft operatively attached to the power tool motor shaft. The elongated output shaft is operatively connected to the motor shaft of the power tool. The output shaft defines a generally cylindrical outer configuration along its length and includes a rearward mounting portion for attachment to the motor shaft and an intermediate portion having the complementarily shaped cavity for receiving the flexible drive shaft.

The present invention generally relates to small handheld power tools, and more particularly to a dust collection attachment system for such tools.
Small handheld power tools that perform drilling, sawing and other types of cutting and the like are known in the prior art and have been widely used by hobbyists, artisans, tradesmen and others in a wide variety of applications. Such rotary hand tools generally have a motor with a rotary output shaft that extends from a nose portion that is more recently configured to connect to various accessories or attachment devices. Some of these rotary hand tools are quite powerful for their size and are used by tradesmen in the building trades as spiral saws that use a side cutting rotary bit to penetrate and rapidly cut holes in drywall sheets and other materials for electrical switches, outlets, light fixtures and the like.
As is known in the art, such rotary hand tool tasks can be more easily performed by using an attachment device that is attached to the tool. For example, a right angle attachment device may be mounted on the power tool and such devices may be configured to drive a circular saw blade, a grinding wheel, a sanding pad or polishing pad.
Such a right angle attachment device has an input shaft that must be interconnected with the output shaft of the tool when the attachment device is mounted on the tool. The interconnection can present problems resulting from the relatively high speed operation, together with misalignment of the two shafts, which can create undesirable vibration. A drive system that minimizes such vibration and facilitates quick and easy mounting and removal of such attachment devices is desirable.

This patent is subject to a terminal disclaimer.

Drive system for interconnecting attachment devices and handheld rotary power tools


Methods and substrate processing systems for analyzing an end point of a process are provided. By-products of the process are detected and monitored to determine the completion of various types of reaction processes within a substrate processing chamber. The methods provide real time process monitoring, thereby reducing the need to rigidly constrain other substrate processing parameters, increasing chamber cleaning efficiency, and/or increasing substrate processing throughput.

1. Field of the Invention
The invention generally relates to methods for forming semiconductor devices and more particularly relates to methods for processing a semiconductor substrate surface.
2. Description of the Related Art
In the field of integrated circuit and flat panel display fabrication, multiple deposition and etching processes are performed in sequence on the substrate within one or more processing chambers to form various design structures. Processes such as etching, physical vapor deposition (PVD), chemical vapor deposition (CVD), chamber cleaning and conditioning, etc. are well known in the industry and each process requires appropriate ways to detect the completion of the desired reaction inside a substrate processing chamber and cleaning of residue build-up on the substrate or the wall of the substrate processing chamber.
In general, silicon oxide, silicon nitride, metal oxide, or metal containing materials are deposited on the surface of a substrate as well as on all exposed surfaces in the substrate processing chamber. These materials may need to be etched or selectively removed in a subsequent process. In addition, these materials or residues may accumulate inside in the substrate processing chamber and must be removed from the chamber surfaces prior to the next deposition or etching process. Otherwise, the material may flake off and deposit on a substrate, thereby compromising the integrity of features formed thereon.
For example, an etch process can be used to remove materials from substrate surface. Plasma etch involves reacting a silicon-containing material on the surface of the substrate with a plasma to generate reaction intermediates as etchants and etch the silicon-containing material on the substrate surface. A requirement in such processes is a prompt termination of etching immediately after the first through, or clear, opening has been developed in the substrate. Stopping the etching process by a predetermined time is not practical because of the differences in film thickness on the surface of a wafer substrate and small surface area of active devices on a small portion of the substrate.
However, conventional end point detectors for plasma etch do not operate reliably during deep trench processes and when device surface areas are small. Such detectors focus a laser on the material to be etched and monitor the phase of the light reflected from the material. As the material is etched (removed), the phase of the reflected light changes in proportion with the depth of the etched area. In this manner, the detector monitors the etch depth and can cause the etching process to stop upon achieving a predetermined depth. To measure minute phase changes, the equipment must be accurately calibrated, and such equipment requires repeated recalibration. Also, as line widths become narrower, maintaining the laser focus upon a bottom of a trench is becoming difficult.
The second class of the end point detectors includes optical emission spectrometry (OES) detectors. These detectors comprise a data acquisition system and a plasma optical emission receiver and detect a change in intensity of one or several wavelengths of the plasma optical emission related to an etched or underlying layer. Sensitivity of these detectors diminishes with either complexity of spectrums or intensity of the plasma as the spectral lines of interest become obscured by background spectrum. Therefore, reliable and accurate end point detection which is critical during plasma etch remains an elusive goal.
On the other hand, pre-cleaning and removal of residual materials from substrate surface or chamber walls may use various chemical compounds that are ignited by exposure to plasma and react with the residual materials to form volatile compounds which can be exhausted from the chamber. Alternatively or additionally, such chemical compounds may form etching species which bombard chamber surfaces to dislodge residue from chamber components. During the time when the chamber cleaning operation is performed, the production of semiconductor devices cannot continue. As a result, the effective productivity of the chamber, as measured by substrate throughput, decreases significantly. To increase the chamber productivity, it is necessary to quickly finish the cleaning operation and restart the production promptly after the end of the cleaning operation. Therefore, it is imperative to precisely determine the end point of a cleaning process.
One method of detecting the end point of the cleaning process monitors a variation in a prescribed light wavelength emitted by the plasma. However, it is difficult to correctly detect the end point of the cleaning operation using this method because light emitted from lamps used to heat the substrate also heats, reacts with or otherwise affects the wavelength monitor, distorting the wavelength reading and resulting in over-cleaning or under-cleaning.
Another method of detecting the endpoint of a cleaning process is to observe the conditions within the chamber through a quartz view port. During processing within the chamber, residue accumulates on the view port, thereby blocking the view into the chamber. As the cleaning process progresses, the residual material is removed from the view port and all the other surfaces in the chamber as well, until the view port is clean and line of sight into the chamber is restored. Once line of sight into the chamber has been restored, the process is continued for approximately 20 to 30 seconds to ensure that the cleaning process is complete. The line of sight detection method does not provide an accurate determination of the endpoint and requires the use of cleaning time beyond the point in time when a clean view port is detected to assure adequate cleaning of the chamber.
In the area of integrated circuit fabrication, time spent in processing substrates and cleaning chambers is an important issue which manufacturers monitor. Time spent cleaning the chamber can be a factor limiting production capabilities. Accordingly, there is a need for a method which is accurate and consistent in determining the endpoint of a process performed inside a chamber. Preferably, the end point of a substrate removal or cleaning process can be determined by adapting existing hardware, monitors, and analyzers in a new process.
Therefore, there is a need for a novel end point detection method to be used for substrate processing or cleaning inside a substrate processing system. There is also a need for real time monitoring of substrate processing reactions or chamber cleaning efficiency.

Methods of end point detection for substrate fabrication processes