bluuebunny/crossref_metadata_2025 huggingface dataset:
Chromosomal Abnormalities in Frozen Shoulder
Authors: Feldman Adam , Delmege David , Bunker Tim
Published: June 2009

Background

Frozen shoulder is a chronic fibrosing condition affecting the capsule of the joint. The predominant cells involved are fibroblasts and myofibroblasts that lay down a dense matrix of type I and type III collagen within the capsule. This subsequently contracts leading to the typical features of pain and stiffness. The histology is very similar to Dupuytren's contracture [1] – [5] . Chromosomal abnormalities, particularly Trisomy 7 and 8, have been found in Dupuytren's disease.

Methods

The aim of this study was to see if there are chromosomal changes in frozen shoulder. The anterosuperior shoulder joint capsule was excised in 16 patients with resistant primary frozen shoulder according to the method of Ozaki et al. [4] . The tissue was examined for chromosomal abnormalities using standard cytogenetic methods.

Results

Ten of the 16 showed chromosomal abnormalities, of which 7 had clonal chromosomal abnormalities; 4 had trisomy 7, 2 had trisomy 8, and 1 both trisomy 7 and 8.

Conclusion

This is approximately the same percentage and numerical type of change to the same chromosomes as previously reported in Dupuytren's disease.
The Relationship between Glenoid Bone Density and the Pullout Strength of Suture Anchors
Authors: Mimar Raghad , Limb David , Hall Richard M.
Published: June 2009

Background

The use of suture anchors in glenoid labral reattachment is now routine in many shoulder procedures. However, debate still surrounds the biomechanical characteristics of suture anchors and the interplay with bone quality.

Methods

Eight embalmed cadaveric glenoids were investigated using a microCT and a tensile testing machine to study the correlation between the bone mineral density of four different regions on the glenoid rim and the pullout strength of the suture anchor. Six constructs failed by suture breakage whilst the remaining 25 positions suffered suture pullout. This study differed from previous investigations by using Orthocord, a much stronger suture material permitting better evaluation of bone properties.

Results

The mean failure load at pullout and suture compromise was 125 ± 40 N and 189 ± 25 N, respectively. The largest value of bone mineral density (BMD) was found at the posterior suture site, whilst the lowest occurred at the inferior edge of the anterior margin. For those constructs that failed by anchor pullout a significant correlation was observed between failure load and local bone mineral density (rPearson = 0.56, p = 0.004).

Conclusion

This relationship between local bone quality and pullout strength maybe a clinical indicator of the relative risk of failure following the suture repairs and warrants further exploration.
Prediction of Rotator Cuff Repair Failure by Histological Analysis
Authors: Matthews Timothy , Brinsden Mark , Athanasou Nicolas , Rees Jonathan , Carr Andrew
Published: June 2009

Background

We aimed to determine if recognised histological features seen in specimens taken during rotator cuff repair could predict which tendon repairs were at risk of re-rupture.

Methods

Forty rotator cuff tendon edge specimens from 40 patients were analysed histologically following routine mini-open rotator cuff repair. Thirty-two patients returned at a mean follow up of 35 months for an ultrasound examination to determine repair integrity.

Results

Overall there were 8 small tears, 13 medium tears, 15 large tears and 4 massive tears. Of the 32 patients followed up with ultrasound scan (USS) the overall re-rupture rate was 46%. Small and medium tears had a re-rupture rate of 35% while 60% of the large and massive tears suffered a re-rupture. Comparison of histological features and repair integrity revealed that the rotator cuff repairs which remained intact demonstrated a greater reparative response, in terms of increased fibroblast cellularity, cell proliferation and a thickened synovial membrane, than those repairs that re-ruptured. The larger tears that did remain intact also showed a higher degree of vascularity and a significant inflammatory component than the larger tears that re-ruptured.

Conclusion

These results indicate the importance of good tissue quality at the time of surgery but that larger tears can heal if the tissue quality is favourable. Post-operative histological analysis of tendon tear edge can aid prognosis and has the potential to guide post-operative immobilization and subsequent physiotherapy.
A Prospective Randomized Placebo Controlled Clinical Trial of a Rehabilitation Programme for Patients with a Diagnosis of Massive Rotator Cuff Tears of the Shoulder
Authors: Ainsworth Roberta , Lewis Jeremy , Conboy Veronica
Published: June 2009

Background

This article compares an exercise regime with a control treatment for the physiotherapy management of patients with massive rotator cuff tears.

Methods

The study design was a randomized placebo controlled trial of 60 patients with radiologically confirmed massive rotator cuff tears evaluating the change from baseline to 3 months, 6 months and 12 months in shoulder function. The primary outcome measure was the Oxford shoulder score.

Results

Both the control and the intervention groups had an improvement in their Oxford shoulder scores at 3 months, 6 months and 12 months. The mean improvement at 3 months was statistically significant in favour of the experimental group (p = 0.002). The mean improvement at 6 months was also statistically significant (p = 0.008) but by 12 months there was no statistically significant difference between the two groups (p = 0.16).

Discussion

The rehabilitation programme for patients with massive rotator cuff tears significantly improved shoulder pain and function in the short term. These improvements in shoulder pain and function were sustained over time although the advantage of intervention against control were not.
Two-Phase Flow Maldistribution and Mitigation in Polymer Electrolyte Fuel Cells
Authors: Basu Suman , Wang Chao-Yang , Chen Ken S.
Published: June 2009

Flow maldistribution among polymer electrolyte fuel-cell (PEFC) channels is of concern because this leads to nonuniform distributions of fuel and oxidizer, which in turn result in nonuniform reaction rates in the catalyst layers and thus detrimentally affect PEFC performance and durability. Channels with low flow rates risk flooding by liquid water. This can cause catalyst support corrosion and hence the undesirably accelerated aging of PEFCs. Multiphase flow computations are performed to examine the effects of gas diffusion layer (GDL) intrusion and manifold design on reducing flow maldistribution. Velocity field, hydrodynamic pressure, and liquid saturations are computed in the parallel gas channels using the multiphase-mixture formulation in order to quantify the flow nonuniformity or maldistribution among PEFC channels. It is shown that, when channel flow is in single phase, employing two splitter plates in the header manifold can bring down the flow maldistribution to less than half of that for the case with 20% area maldistribution due to the GDL intrusion. When channel flow occurs in the two-phase regime, the liquid-water front can be pushed downstream and the effect of GDL intrusion on the maximum liquid saturation can be decreased by more than one-third by using flow splitters.
Use of Optimal Controls to Mitigate Competing Performance Objectives in a Polymer Electrolyte Membrane Fuel Cell System
Authors: Howe Matthew A. , Rocheleau David N.
Published: June 2009

This paper describes a model predictive control (MPC) scheme as implemented on a polymer electrolyte membrane fuel cell system. The goal of this work is to reduce parasitic power consumption of the system, improving net system efficiency. The MPC is capable of balancing this performance objective (reducing power loss) with the objective of maintaining oxygen excess ratio, a parameter identified as essential to reliable fuel cell operation. Two configurations of a MPC were implemented in SIMULINK and connected to a dynamic system model in EASY5 using the XML (extensible markup language) metadata interchange (XMI) interface. Substantial improvements were noted on one of the MPC configurations compared to the reference feedforward and proportional-integral-derivative (PID) controller.
Hybrid Simulation Facility Based on Commercial 100 kWe Micro Gas Turbine
Authors: Ferrari Mario L. , Pascenti Matteo , Bertone Roberto , Magistri Loredana
Published: June 2009

A new high temperature fuel cell-micro gas turbine physical emulator has been designed and installed in the framework of the European Integrated Project “FELICITAS” at the Thermochemical Power Group (TPG) laboratory located at Savona. The test rig is based on a commercial 100 kWe recuperated micro gas turbine (mGT) (Turbec T100) modified to be connected to a modular volume designed for physical emulation of fuel cell stack influence. The test rig has been developed starting with a complete theoretical analysis of the micro gas turbine design and off-design performance and with the definition of the more flexible layout to be used for different hybrid system (molten carbonate fuel cell or solid oxide fuel cell) emulation. The layout of the system (connecting pipes, valves, and instrumentation, in particular mass flow meter locations) has been carefully designed, and is presented in detail in this paper. Particular attention has been focused on the viscous pressure loss minimization: (i) to reduce the unbalance between compressor and expander, (ii) to maintain a high measurement precision, and (iii) to have an effective plant flexibility. Moreover, the volume used to emulate the cell stack has been designed to be strongly modular (different from a similar system developed by U.S. Department Of Energy-National Energy Technology Laboratory) to allow different volume size influence on the mGT rig to be easily tested. The modular high temperature volume has been designed using a computational fluid dynamics (CFD) commercial tool (FLUENT). The CFD analysis was used (i) to reach a high level of uniformity in the flow distribution inside the volume, (ii) to have a velocity field (m/s) similar to the one existing inside the emulated cell stack, and (iii) to minimize (as possible) the pressure losses. The volume insulation will also allow to consider a strong thermal capacity effect during the tests. This paper reports the experimental results of several tests carried out on the rig (using the mGT at electrical stand-alone conditions with the machine control system operating at constant rotational speed) at different load values and at both steady-state and transient conditions.
Cathode Properties of SmxSr1−x(Co,Fe,Ni)O3−δ/Sm0.2Ce0.8O1.9 Composite Material for Intermediate Temperature-Operating Solid Oxide Fuel Cell
Authors: Baek Seung-Wook , Lee Changbo , Bae Joongmyeon
Published: June 2009

Perovskite-structured cathode material containing samarium (Sm) has been recognized as a promising electrode material due to its high electrocatalytic property for intermediate temperature-operating solid oxide fuel cell (IT-SOFC). This research investigated the optimized composition of SmxSr1−x(Co,Fe,Ni)O3−δ/Sm0.2Ce0.8O1.9 on the Sm0.2Ce0.8O1.9 electrolyte and the possible use of an optimized composite material for the IT-SOFC system. The electrochemical and thermal properties of SmxSr1−x(Co,Fe,Ni)O3−δ and its composite material with the Sm0.2Ce0.8O1.9 electrolyte were investigated in terms of area specific resistance (ASR) and thermal expansion coefficient at various temperature conditions. Durability of the selected materials was verified by thermal cycling and long-term degradation tests. Sm0.5Sr0.5CoO3−δ and the Sm0.5Sr0.5CoO3−δ/Sm0.2Ce0.8O1.9(6:4) composite cathode showed a very low ASR of 0.87 Ωcm2 and 0.30 Ωcm2 at 600°C, respectively. The composite type cathode for the Sm0.5Sr0.5CoO3−δ material was more attractive due to its thermal expansion compatibility with neighboring cell components.
Polarization Resistances of (Ln1−xSrx)CoO3 (Ln=Pr, Nd, Sm, and Gd x=0, 0.3, 0.5, 0.7, and 1) as Cathode Materials for Intermediate Temperature-operating Solid Oxide Fuel Cells
Authors: Kim Jung Hyun , Baek Seung-Wook , Bae Joongmyeon
Published: June 2009

This study focuses on cathode performances of (Ln1−xSrx)CoO3−δ (Ln=Pr, Nd, Sm, and Gd, x=0, 0.3, 0.5, 0.7, and 1) for intermediate temperature-operating solid oxide fuel cells (IT-SOFCs, 600–800°C). (Ln1−xSrx)CoO3−δ powders as cathode materials for IT-SOFC, which can be operated between 600°C and 800°C were synthesized by the glycine-nitrate-process (GNP) method. The impedance spectroscopy method was used to investigate area specific resistance (ASR) and electrochemical properties of (Ln1−xSrx)CoO3−δ (Ln=Pr, Nd, Sm, and Gd, x=0, 0.3, 0.5, 0.7, and 1). Pr0.5Sr0.5CoO3−δ and Pr0.3Sr0.7CoO3−δ showed to 0.15 Ω cm2 of ASR at 700°C and Nd0.5Sr0.5CoO3−δ to 0.14 Ω cm2 at 700°C. Sm0.5Sr0.5CoO3−δ showed the lowest ASR values of 0.10 Ω cm2 on 10% Gd-doped cerium oxide at 700°C.
Joining of Metallic Cap and Anode-Supported Tubular Solid Oxide Fuel Cell by Induction Brazing Process
Authors: Kim Jong-Hee , Song Rak-Hyun , Shin Dong-Ryul
Published: June 2009

The anode-supported tubular solid oxide fuel cells were fabricated and joined onto the metal cap (SUS430) for current collecting and sealing by using the induction brazing process. Among five filler materials used in the induction brazing, Ni-based BNi2 has shown the lowest gas permeability of 1×10−6 l cm−2 s−1 at a differential pressure of 3 atm measured with He gas. The electrical conductivity of anode support brazed with BNi2 showed 450 S cm−1 at 750°C and stable value even at the long-term and thermal cycle tests. The brazed anode-supported tubular cell at operating temperature of 750°C produced 210 mW/cm2 at 0.7 V. The gas-tightness was confirmed by open circuit voltage (OCV) value similar to theoretical value. The cell showed a stable performance and OCV for 200 h.
Oxidation Behavior of Various Metallic Alloys for Solid Oxide Fuel Cell Interconnect
Authors: Chu Chun-Lin , Wang Jian-Yih , Lee Ruey-Yi , Lee Tien-Hsi , Lee Shyong
Published: June 2009

Ten iron-based alloys and nickel-based alloys were subjected to oxidation treatment in a hot air environment for various periods. In this investigation, all alloys contained a certain amount of Cr, and Cr2O3 and (Mn,Fe,Cr)3O4 spinel compounds are generated on the surface oxides. Other spinels that contain Cr, Mn, Fe, and Ni are also formed on it; the compositions depend on the composition of the steels and any other materials that are in contact with the interconnects. Accordingly, the role of spinels in the oxidation of interconnects must be understood.
On the Use of Pressure-Loaded Blister Tests to Characterize the Strength and Durability of Proton Exchange Membranes
Authors: Dillard David A. , Li Yongqiang , Grohs Jacob R. , Case Scott W. , Ellis Michael W. , Lai Yeh-Hung , Budinski Michael K. , Gittleman Craig S.
Published: June 2009

The use of pressurized blister specimens to characterize the biaxial strength and durability of proton exchange membranes (PEMs) is proposed, simulating the biaxial stress states that are induced within constrained membranes of operating PEM fuel cells. PEM fuel cell stacks consist of layered structures containing the catalyzed PEMs that are surrounded by gas diffusion media and clamped between bipolar plates. The surfaces of the bipolar plates are typically grooved with flow channels to facilitate distribution of the reactant gases and water by-product. The channels are often on the order of a few millimeters across, leaving the sandwiched layers tightly constrained by the remaining lands of the bipolar plates, preventing in-plane strains. The hydrophilic PEMs expand and contract significantly as the internal humidity, and to a lesser extent, temperature varies during fuel cell operation. These dimensional changes induce a significant biaxial stress state within the confined membranes that are believed to contribute to pinhole formation and membrane failure. Pressurized blister tests offer a number of advantages for evaluating the biaxial strength to bursting or to detectable leaking. Results are presented for samples of three commercial membranes that were tested at 80°C and subjected to a pressure that was ramped to burst. The bursting pressures exhibit significant time dependence that is consistent with failure of viscoelastic materials. Rupture stresses, estimated with the classic Hencky’s solution for pressurized membranes in conjunction with a quasielastic estimation, are shown to be quite consistent for a range of blister diameters tested. The technique shows considerable promise not only for measuring biaxial burst strength but also for measuring constitutive properties, creep to rupture, and cyclic fatigue damage. Because the tests are easily amenable to leak detection, pressurized blister tests offer the potential for characterizing localized damage events that would not be detectable in more commonly used uniaxial strength tests. As such, this specimen configuration is expected to become a useful tool in characterizing mechanical integrity of proton exchange membranes.
System Architectures for Solid Oxide Fuel Cell-Based Auxiliary Power Units in Future Commercial Aircraft Applications
Authors: Braun R. J. , Gummalla M. , Yamanis J.
Published: June 2009

Recent advancements in fuel cell technology through the auspices of the Department of Energy, the National Aeronautics and Space Administration, and industry partners have set the stage for the use of solid oxide fuel cell (SOFC) power generation systems in aircraft applications. Conventional gas turbine auxiliary power units (APUs) account for 20% of airport ground-based emissions. Alleviating airport ground emissions will continue to be a challenge with increased air travel unless new technology is introduced. Mission fuel burn and emissions can be significantly reduced through optimal systems integration of aircraft and SOFC subsystems. This study examines the potential total aircraft mission benefits of tightly integrating SOFC hybrids with aircraft subsystems using United Technologies Corporation Integrated Total Aircraft Power Systems proprietary methodologies. Several system concepts for optimal integration of the SOFC stack with aircraft subsystems are presented and analyzed in terms of mission fuel burn for technologies commensurate with 2015 entry into service. The performance of various hybrid SOFC-APU system architectures is compared against an advanced gas turbine-based APU system. In addition to the merits of different system architectures, optimal SOFC system parameter selection is discussed. The results of the study indicate that despite the lower power density of SOFC-based APU systems, significant aircraft fuel burn (5–7%) and emission reductions (up to 70%) are possible. The majority of the fuel burn savings are realized during aircraft ground operations rather than in-flight mission segments due to the greater efficiency difference between the SOFC system and the advanced APU technology.
Hydrocarbon Condensation Heating of Natural Gas by an Activated Carbon Desulfurizer
Authors: Israelson Gordon
Published: June 2009

A phenomenon was observed after exposing a fresh bed of activated carbon to a flow of natural gas that included several percent of ethane and propane in addition to the bulk methane. For several hours the temperature of the natural gas exiting the carbon bed was about 30°C higher than the temperature of the gas entering the bed. This phenomenon can be attributed to release of the latent heat of vaporization due to condensation of all of ethane and propane into the pores of carbon. Due to its hydrophobic nature carbon is not expected to produce significant condensation of water vapor. The calculated additional water vapor condensation heat release and its related temperature increase was not observed.
Geometry Driven Decision Support System for Knee Tumour Mega Endo-Prosthesis Components Selection
Authors: Subburaj K. , Suresh P. , Anasane S. S. , Ravi B. , Agarwal M. G.
Published: June 2009

Modular endo-prostheses were introduced in 1980s with the intent of replacing custom made implants, which were criticized for lack of intra-operative flexibility, and high lead time and cost [1]. A typical modular prosthesis set may have as many as 200 components, making it difficult to select the right set of components in intra operative stage. An automated prosthesis selection methodology to limit the choice of prosthesis components with a qualitative tag such as: (1) ‘most suitable’, (2) ‘probably suitable’, and (3) ‘not suitable’, will greatly help the surgeons. This article describes a computer aided decision support system for selecting endo-prosthesis components driven by anatomical data of the patient. The methodology is explained with a case study of distal femur replacement.
Endo-Distraction: A New Technique of Distraction Osteogenesis in High Atrophic Mandibles — Results of 18 Patients
Authors: Krenkel Christian
Published: June 2009

The aim of this study is to evaluate the surgical and prosthetic results of edentulous patients with highly atrophic mandibles using the Endo-Distraction technique.
Production of Monodisperse Micron-Size Droplets Using Silicon-Based MHz Ultrasonic Nozzles for Biomedical Applications
Authors: Tsai Shirley C. , Song Yu L. , Cheng Chih H. , Wang Ning , Mao Rong W. , Chou Yuan F. , Lee Chin T. , Tsai Chen S.
Published: June 2009

This paper reports production of 4.5 μm-diameter monodisperse water droplets using silicon-based one MHz ultrasonic nozzles of a novel design. The novel design of multiple Fourier horns in resonance facilitates pure capillary wave mechanism atomization. The measured drop diameters are in very good agreement with those predicted by the capillary wave atomization mechanism. Due to the resonance effect, the power and voltage requirements for atomization were as low as 15 mW and 6.5 V at atomization rate as high as 300 μl/min. The droplet diameter was reduced to 4.1 μm when the surface tension of the liquid was reduced from 70 dyne/cm (water) to 50 dyne/cm (0.25% Triton X-100 surfactant solution). Such small diameter drops with GSD (geometrical standard deviation) as small as 1.1 was achieved in ultrasonic atomization for the first time. Note that the fraction of all particles smaller than 5.8 μm in diameter represents the inhaleable fine particle fraction and GSD of 1.3 or smaller is commonly accepted as the standard for monodispersity. Therefore, the MEMS-based MHz ultrasonic nozzle should have very significant impacts on targeted delivery of reproducible doses of medicine to the respiratory system.
Computational Mechanics of the Sclera and Optic Nerve Head (ONH): Effects of ONH Size and Pressure Range
Authors: Waldman Lewis , Cunanan Crystal , Asrani Sanjay , Kerckhoffs Roy , McCulloch Andrew
Published: June 2009

Computational modeling was performed to study how loss of compliance of the eye and abnormally high pressures result in changes in stresses and strains that may impact the optic nerve in diseases such as glaucoma. Hemispherical finite element models of the eye were created in which scleral thickness varied from the equatorial region to the optic nerve head (ONH). Nonhomogeneous material properties were used to model the ONH as a continuous region softer than the adjacent sclera. The ONH and an adjacent buffer zone in the sclera were modeled with enough detail that the size of the ONH could be changed to account for variations observed in humans. The model was provided with appropriate dimensions typical of patients and nonlinear material properties with decreased compliance. Models with different ONH sizes were inflated in small steps to 55 mmHg (7.33 kPa), providing deformed configurations at intermediate pressures of 15, 30 and 45 mmHg, respectively. Color-coded maps of stress and strain components were rendered directly on deformed configurations of the eye model; and animations were produced that show both spatial and temporal variations of stresses and strains as internal pressure increases. Three-dimensional stresses and accompanying finite strains were similar for ONH sizes ranging form 1.5 to 2.5 mm in diameter. Stress and strain differences were estimated as pressure was increased from 15 to 25 mmHg, 30 to 40 mmHg, and 45 to 55 mmHg. Substantial changes occurred in stress and strain differences as the pressure range was varied with large changes occurring in the lowest pressure range for strain components and moderate increases in stress differences as pressures increase.
Micropallet Technology for Investigating Tumor Cellular Profiles and Analysis of Rare Cell Subsets
Authors: Gunn Nicholas M. , Bachman Mark , Nelson Edward L. , Li G.-P.
Published: June 2009

Rationally designed, individualized therapeutic strategies have long been a desired objective for breast cancer patients and clinicians as an estimated 178,480 new cases of invasive breast cancer will be diagnosed among women in the United States this year and over 40,000 women are expected to die from the disease. [1] The increasing appreciation of breast tumor cellular heterogeneity raises fundamental questions as to the relative contributions of cellular subsets to the biologic behavior of an individual patient’s tumor. [2] As such, it has become increasingly clear that in many cases, an individualized strategy for the treatment of breast cancer would be of great benefit, and that the ability to isolate relevant cellular subsets from the main tumor population is one of the critical limits to accomplishing this goal.
Bending, Torsional, and Pullout Strength of Compression Screws in Cadaver Foot and Ankle Specimens
Authors: Pfeiffer Ferris M. , Shurnas Paul S. , Abernathie Dennis L. , Ronan James A.
Published: June 2009

It has been well supported in the literature that using compression screws is the preferred method to achieve fixation of an arthrodesis [1, 2]. Indications for isolated subtalar arthrodesis include trauma, arthritis, talocalcaneal coalition, adult acquired flatfoot, posterior tibial tendon dysfunction, and Charcot neuroarthropathy [3, 4]. With the increase in bone screw shapes and designs, there is a desire to achieve the best compression generated by a type of screw so as to promote excellent bone healing and outcome for the patient; this will also allow the stability of the construct achieved by the screw and its placement to be determined. As indicated by Wheeler, et. al.[5] screw choice, compression, stability and loading can be very important when it comes to healing of fractures in small bones.
Stent Artery Interaction and Its Significance on Stent Durability in the SFA and Femoropopliteal Arteries
Authors: Zeng Ken
Published: June 2009

Lack of detailed stent artery interactions is responsible for rampant stent fracture in the human SFA or popliteal arteries. Armed with recent research work quantifying dynamic changes of the SFA and popliteal vessels, we investigated stent deformations under various modes of dynamic physiological conditions and their interactions using realistic artery constitutive models. Fatigue strains were calculated using finite element analysis and were compared with material’s endurance limit data obtained using a special V-shape sample. A linear damage accumulation formula (Minor’s rule) was employed to predict safety factors for the stent.
Construct Validity for the UCLA Laparoscopic Training System
Authors: Nistor V. , Allen B. , Faloutsos P. , Dutson E. , Carman G. P.
Published: June 2009

This study aims to establish the construct validity of new Laparoscopic Training Simulator (LTS) developed at UCLA. The system was developed due to the increasing demand for Minimally Invasive Surgery (MIS) coupled with the difficulty associated in training surgeons in the use of MIS techniques with traditional apprenticeship models. In addition to training issues, there exists an immediate need for an objective assessment of Minimally Invasive Surgery (MIS) skills and techniques required to ensure safe and high quality treatment as previously established [1]. While currently available training systems have been used they are slow in educating new surgeons and they do not provide an objective assessment. The new system developed UCLA-LTS [2] addresses these very issues by combining the simplicity of the traditional training box with the advances in computer simulation technology to both train and to assess skill level.
Development of a Shape Memory Alloy Actuated Catheter for Cardiovascular Procedures
Authors: Veeramani Arun S. , Crews John H. , Buckner Gregory D. , Owen Stephen B. , Cook Richard C. , Bolotin Gil
Published: June 2009

This research highlights the design, fabrication and experimental validation of a Shape Memory Alloy (SMA) actuated robotic catheter. The prototype consists of four SMA tendons that actuate a central tubular substructure in two orthogonal directions. The experimental shape memory characteristics are used to optimize the design. Joule heating is used to generate tip deflections and the experimental bending characteristics are obtained using a dual camera imaging system. These measurements reveal important nonlinearities and hysteretic characteristics of the system. A dynamic model of the system is developed to describe the SMA-effected bending mechanics, and simulation results are compared to experimental measurements for model validation. The applicability of this technology to cardiovascular procedures, like atrial ablation, is demonstrated through precise tracking of trajectories using PID control.
High-Index Optical Materials for High-Throughput Lensfree Imaging, Counting and Sorting of Cells on a Chip
Authors: Seo Sungkyu , Su Ting-Wei , Erlinger Anthony , Ozcan Aydogan
Published: June 2009

We describe a high-throughput lensfree optical imaging system that can characterize numerous cell types found within a heterogeneous mixture. Here, we specifically discuss the effect of the refractive index of the substrate material on the performance of the proposed lensfree optical cell characterization platform. It is experimentally illustrated that the use of high index materials such as SrTiO3 significantly improves the signal-to-noise ratio of the acquired lensfree images, which is a significant step towards more robust high-throughput cell analysis and characterization. The imaging configuration of the reported high-index material based characterization scheme is massively parallel enabling a cell counting speed of >100,000 cells/sec over a field of view of ∼10 cm2. This novel system can also form the basic building block of a simple and compact point-of-care cell counting technology that can be made as small as a regular cell-phone to rapidly measure the count of e.g., red blood cells or T-lymphocytes from whole blood samples. Such a powerful point-of-care platform may have a significant impact especially for global health related problems in the developing world.
A Concept for a Novel Procedure for Mitral Valve Repair by Percutaneous Annuloplasty
Authors: Azar Toufic , Rajagopalan Sumitra , Cecere Renzo , Kovecses Joszef , Angeles Jorge
Published: June 2009

Mitral valve regurgitation [1] (MVR) is a functional heart disease in which the valve does not close completely and causes blood to leak back into the left atrium. This condition increases the workload on the heart, and if left untreated, can lead to irreversible heart damage, cardiac arrhythmia, and congestive heart failure. Annually, in the United States, more than 50 000 patients undergo mitral valve repair. The causes of MR can be either primary, due to an anatomical change of the valve apparatus, or secondary to ischemic heart disease and idiopathic cardiomyopathy. Currently, the intervention requires an open heart surgery with cardiopulmonary bypass. Under such conditions, the patient is subjected to intra and post-operative trauma that can result in a mortality increase and that can prevent high risk individuals from undergoing the repair. A non-invasive percutaneous method would greatly reduce risks associated with a conventional surgery while increasing the potential candidates for repair. Introduced in this paper is a concept for a novel procedure that relies on a robotically-guided compliant catheter, fitted with an anchoring mechanism, intended to reshape the mitral-valve annulus to dimensions suitable for the effective support of the valve leaflets.
Smart Endoscopic Tool for the Measurement of Force and Softness of Grasped Object in Minimally Invasive Surgery
Authors: Ramezanifard M. , Sokhanvar S. , Xie W. , Packirisamy M. , Dargahi J.
Published: June 2009

One of the shortcomings of the current endoscopic graspers is the lack of tactile sensing. We are reporting the results of the first stage of a research project to rectify the tactile sensing in endoscopic tools. This paper introduces a smart endoscopic grasper equipped with sensors for measuring the applied force and the angle of the grasper tip. It is shown that using this method, the softness of the grasped object can be estimated. The next phase of this research would be devising an appropriate method to feedback the measured date.
Shock Wave Lithotripters With Broad Focus Result in Greater Stress in Human Kidney Stones: Numerical Simulation
Authors: Luo Haibiao , Cleveland Robin O. , Williams James C.
Published: June 2009

Shock wave lithotripsy (SWL) has been used to treat kidney stones for decades. However, there is growing recognition that shock waves induces trauma to kidney tissue [1, 2]. The poor understanding of stone comminution mechanisms means that the design of new lithotripters is principally a practice of empiricism [3]. A mechanistic understanding of stone comminution would provide a criterion to develop new lithotripsy systems. In this work, a three-dimensional finite-difference time-domain (FDTD) solution to the linear elastic equations was employed [4] to investigate the stress and displacement fields of kidney stones subject to lithotripsy shock waves. The kidney stone models were obtained from micro-computed tomography images (resolution of 20 μm) and have diameters from 2 mm to 5 mm.
Microfluidic CD-Based Systems Toward Rapid Anthrax Detection in Whole Blood
Authors: Siegrist Jonathan , Amasia Mary , Kido Horacio , Zoval Jim , Madou Marc
Published: June 2009

Anthrax is an acute and deadly disease caused by the bacterium Bacillus anthracis. Upon exposure, usually through inhalation, ingestion, or cutaneous contact, B. anthracis spores begin multiplying, creating a life-threatening situation. If not quickly detected and treated, humans can die within several days. With renewed bio-terrorism concerns, there is a need for a rapid and automated system capable of sample (respiratory or blood) to answer (positive infection) so that quarantine procedures and treatment can be administered immediately. Microfluidic platforms hold great promise of fulfilling these requirements.
EONS Synaptic Modeling Platform: Exploration of Mechanisms Regulating Information Processing in the CNS and Application to Drug Discovery
Authors: Allam Sushmita L. , Bouteiller Jean-Marie C. , Greget Renaud , Bischoff Serge , Baudry Michel , Berger Theodore W.
Published: June 2009

EONS modeling platform is a resourceful learning and research tool to study the mechanisms underlying the non-linear dynamics of synaptic transmission with the aid of mathematical models. Mathematical modeling of information processing in CNS pathways, in particular modeling of molecular events and synaptic dynamics, have not been extensively developed owing to the complex computations involved in integrating a multitude of parameters. In this paper, we discuss the development of a strategy to adapt the EONS synaptic modeling platform to a multi-node environment using a parallel computational framework to compute data intensive long simulations in a shorter time frame. We describe how this strategy can be applied to (i) determine the optimal values of the numerous parameters required for fitting experimental data, (ii) determine the impact of all parameters on various aspects of synaptic transmission (under normal conditions or conditions mimicking pathological conditions) and (iii) study the effects of exogenous molecules on both healthy and pathological synaptic models.
Application of Split Flow Design Technique to Simple Microchannel Geometries for Enhanced Mixing
Authors: Bhopte Siddharth , Sammakia Bahgat , Murray Bruce
Published: June 2009

The ability to control mixing of reagents in MEMS systems is crucial for many biological and chemical analysis applications. However mixing in these microfluidic devices is a challenge because the flows are laminar corresponding to very low Reynolds number. In this paper mixing of such reagents in simple microchannel geometries is investigated computationally. A novel concept of “split flow design” is applied to these simple microchannel configurations. Significant improvement in mixing is seen by employing the split flow design technique.
ISO Standardization of the Scaling Factor Method for Low- and Intermediate Level Radioactive Wastes Generated at Nuclear Power Plants
Authors: Kashiwagi Makoto , Masui Hideki , Denda Yasutaka , James David , Lante`s Bertrand , Mu¨ller Wolfgang , Garamszeghy Mike , Leganes Jose Luis , Maxeiner Harald , van Velzen Leo
Published: June 2009

Low- and intermediate-level radioactive wastes (L-ILW) generated at nuclear power plants are disposed of in various countries. In the disposal of such wastes, it is required that the radioactivity concentrations of waste packages should be declared with respect to difficult-to-measure nuclides (DTM nuclides), such as C-14, Ni-63 and α-emitting nuclides, which are often limited to maximum values in disposal licenses, safety cases and/or regulations for maximum radioactive concentrations. To fulfill this requirement, the Scaling Factor method (SF method) has been applied in various countries as a principal method for determining the concentrations of DTM nuclides. In the SF method, the concentrations of DTM nuclides are determined by multiplying the concentrations of certain key nuclides by SF values (the determined ratios of radioactive concentration between DTM nuclides and those key nuclides). The SF values used as conversion factors are determined from the correlation between DTM nuclides and key nuclides such as Co-60. The concentrations of key nuclides are determined by γ ray measurements which can be made comparatively easily from outside the waste package. The SF values are calculated based on the data obtained from the radiochemical analysis of waste samples. The use of SFs, which are empirically based on analytical data, has become established as a widely recognized “de facto standard”. A number of countries have independently collected nuclide data by analysis over many years and each has developed its own SF method, but all the SF methods that have been adopted are similar. The project team for standardization had been organized for establishing this SF method as a “de jure standard” in the international standardization system of the International Organization for Standardization (ISO). The project team for standardization has advanced the standardization through technical studies, based upon each country’s study results and analysis data. The conclusions reached by the project team was published as ISO International Standard 21238:2007 “The Scaling Factor method to determine the radioactivity of low- and intermediate-level radioactive waste packages generated at nuclear power plants” [1]. This paper gives an introduction to the international standardization process for the SF method and the contents of the recently published International Standard.
Using Pressure Decay Methodology to Detect Glovebox Glove Failures
Authors: Cournoyer Michael E. , Schreiber Stephen , Chunglo Steve D.
Published: June 2009

At the Los Alamos National Laboratory Plutonium’s Facility (TA-55), various isotopes of plutonium along with other actinides are handled in a glove box environment. Data collected from 700 unplanned openings in the glovebox environment indicate that 40% of these ruptures are glove failures, openings in the glove caused by degradation of the mechanical properties over time, e.g. exposure to chemicals and nuclear materials. The primary means of minimizing these types of glove failures is through a robust glove inspection program. Through a collaborative effort with Getinge La Calhe`ne, we have beta-tested their In-situ Glove Leak Tester (GLT2) in an active ventilation glovebox environment. This instrument tests glovebox gloves in place and uses pressure decay methodology, to tests up to four gloves at a time, in less than 5 minutes per test, and provides documentation of each test. While the GLT2 has been successful in static pressure enclosures that are possible in the pharmaceutical industry, the uninterruptible active negative pressure gloveboxes used in the nuclear industry present a new set of issues. In the following report, these issues are addressed and the limits of this technology defined, with the end result being that waste generated from glove failures has been minimized.
WDC: Advanced System for Characterization of Alpha-Bearing Waste Contained in 200L and 400L Drums: Performances and Lessons Learned From the First Industrial Measurement Campaigns
Authors: Libens A. , Vandorpe M. , Cuchet J. M.
Published: June 2009

The Waste Drum Characterization installation was originally developed for the assay of alpha-bearing waste in standard 200 l (55 gallons) drums during the dismantling operations of the Siemens mixed-oxide (MOX) facility in Hanau (Germany). That installation was validated and qualified by the German authorities, its main performances being: - Counting efficiency for coincident neutrons: app. 1%; - Lowest Limit of Detection (LLD): 75 mg 240Pueq; - Pu content per drum: up to 100 g tot. (35 g 240Pueq); - Measurement duration: app. 20 minutes. The success of this system, a passive neutron coincidence counter combined with a high resolution gamma spectrometer, led to the radiological characterization and qualification of about 1,700 drums during the period 2001 – 2004. In 2005, after completion of the dismantling operations of the Siemens MOX facility, Tecnubel took over the WDC installation which could be used in the frame of the future dismantling of the Belgonucleaire’s MOX plant in Dessel (Belgium), which can be comparable to the Siemen’s one. This second (and new) life for the WDC means that it must be rigorously retested and validated against the Belgian authorities requirements. Furthermore, and additionally to the future use in the Belgonucleaire’s facility, Tecnubel was faced with new challenges, namely: - Assay of 400 l drums together with the 200 l packages; - Determination of the real LLD taking into account the background in different Belgian nuclear facilities, the determination of a value of ∼5 mg 240Pueq being an objective; - Assay of mixed alpha/beta-gamma wastes; - Transportability of the WDC from one plant to another; - Assistance to different nuclear operators for the licensing of the WDC for their own waste types. This paper describes the installation itself and its performances, presents the difficulties encountered during the new challenge and the results of the performed revalidation tests; it gives the perspectives and objectives on short time as well.
Centrifuge Modeling of Radioactive Waste Migration Through Backfill in a Near Surface Disposal Facility
Authors: Gurumoorthy C. , Kusakabe O.
Published: June 2009

Investigations on the performance of backfill barrier in Near Surface Disposal Facility (NSDF) for radioactive wastes are important to ensure the long term safety of such disposal option. Favorable condition to delay migration of radionuclides from disposed waste to far fields is diffusion process. However, advective dispersion/diffusion mechanism plays an important role due to changes in backfill over a period of time. In order to understand these mechanisms, detailed laboratory experiments are usually conducted for developing mathematical models to assess the behaviour of backfill. However, these experiments are time consuming and suffer with the limitations due to material complexity. Also, there are constraints associated with validation of theoretical predictions due to intricacy of boundary conditions as well as the time scale is quite different as compared to the time required for completion of the processes in the field. Keeping in view these aspects, centrifuge modeling technique has been adopted by various researchers to model and understand various geoenvironment problems in order to provide a link between the real life situation termed as the ‘Prototype’ and its model, which is exposed to a higher gravitational field. An attempt has been made in this paper to investigate the feasibility of this technique to model advective dispersion/diffusion mechanism of radionuclides through saturated Bentonite-Sand (B:S) backfill. Various stages of centrifuge modeling are highlighted. Column tests were conducted in the centrifuge to evaluate the hydraulic conductivity of B:S mixture under prototype NSDF stress conditions. Results showed that steady state hydraulic conductivity under saturated conditions was 2.86 × 10−11m/sec. Studies indicate the feasibility of centrifuge modeling technique and usefulness to model advective diffusion of radionuclides through B:S backfill.
Lower Bound of Optimization in Radiological Protection System Taking Account of Practical Implementation of Clearance
Authors: Hattori Takatoshi
Published: June 2009

The dose criterion used to derive clearance and exemption levels is of the order of 0.01 mSv/y based on the Basic Safety Standard (BSS) of the International Atomic Energy Agency (IAEA), the use of which has been agreed upon by many countries. It is important for human beings, who are facing the fact that global resources for risk reduction are limited, to carefully consider the practical implementation of radiological protection systems, particularly for low-radiation-dose regions. For example, in direct gamma ray monitoring, to achieve clearance level compliance, difficult issues on how the uncertainty (error) of gamma measurement should be handled and also how the uncertainty (scattering) of the estimation of non-gamma emitters should be treated in clearance must be resolved. To resolve these issues, a new probabilistic approach has been proposed to establish an appropriate safety factor for compliance with the clearance level in Japan. This approach is based on the fundamental concept that 0.1 mSv/y should be complied with the 97.5th percentile of the probability distribution for the uncertainties of both the measurement and estimation of non-gamma emitters. The International Commission on Radiological Protection, ICRP published a new concept of the representative person in Publication 101 Part I. The representative person is a hypothetical person exposed to a dose that is representative of those of highly exposed persons in a population. In a probabilistic dose assessment, the ICRP recommends that the representative person should be defined such that the probability of exposure occurrence is lower than about 5% that of a person randomly selected from the population receiving a high dose. From the new concept of the ICRP, it is reasonable to consider that the 95th percentile of the dose distribution for the representative person is theoretically always lower than the dose constraint. Using this established relationship, it can be concluded that the minimum dose constraint that requires optimization in radiological protection should be set to the dose criterion of 0.1 mSv/y, considering the fundamental concept used in the clearance criterion for resolving the issues on uncertainty in clearance.