bluuebunny/crossref_metadata_2025 huggingface dataset:
Tension Band Wiring of Olecranon Fractures
Authors: Davies Mark Bowen , Kam King Charles Kon , Stanley David
Published: June 2009

Background

Tension band wiring of olecranon fractures has been shown to be associated with a high rate of metalwork removal. The purpose of this study was to investigate whether this remained true or whether there had been a reduction in metalwork removal following improvements in surgical technique.

Methods

The outcome of 44 olecranon fractures treated by tension band wire fixation were reviewed. Eighteen (41%) required a second operation to remove the metalwork. In order to determine what factors might pre-dispose to metalwork removal continuous (age) and categorical variables (sex, k-wire diameter, k-wire alignment, k-wire orientation, k-wire length distal to the fracture and the number of tightening loops on the cerclage wire) were evaluated.

Results

No statistical significance was identified when each variable was analysed individually or cumulatively using a multiple backward stepwise logistic regression (P<0.05). Using Kaplan-Meier survivorship analysis removal of the tension band device was found to be most commonly performed within 6 months of the index procedure.

Conclusion

This study indicates that metalwork removal is more importantly related to anatomical site rather than the specific surgical technique.
The Results of Subacromial Decompression in Patients with and without Rotator Cuff Tears
Authors: Powell Eric S. , Auplish Sunil , Trail Ian A. , Haines John F.
Published: June 2009

Background

The decision to repair the rotator cuff in patients with impingement is controversial. This study aimed to determine whether there was a difference in outcome in patients both with and without rotator cuff tears undergoing subacromial decompression (SAD).

Methods

Ninety-eight patients underwent an arthroscopic SAD for impingement. No rotator cuff tear was repaired. The patients were assessed pre-operatively, at 6 months and 3 years using the ASES, Constant, DASH and the physical SF-36 scores. The rotator cuff was categorized as ‘tear/no tear’ depending on whether a cuff tear was present.

Results

Both the ‘tear’ and ‘no tear’ groups showed a significant improvement with all scores at 6 months and 3 years. There was no significant difference in these outcome measures between the ‘tear’ and ‘no tear’ groups at 6 months. At 3 years there was no significant difference between the groups using the ASES and DASH scores, but there was a significant improvement in the Constant and SF-36 scores in the ‘no tear’ group.

Conclusion

SAD significantly improves outcome even in patients whose cuff tear was left unrepaired. Comparison of the ‘tear’ and ‘non-tear’ patient groups suggest that cuff tears can be left unrepaired in selected patients.
Going to Scale with Community‐Led Total Sanitation: Reflections on Experience, Issues and Ways Forward
Authors: Chambers Robert
Published: June 2009

Perhaps as many as 2 billion people living in rural areas are adversely affected by open defecation (OD). Those who suffer most from lack of toilets, privacy and hygiene are women, adolescent girls, children and infants. Sanitation and hygiene in rural areas have major potential for enhancing human wellbeing and contributing to the MDGs. Approaches through hardware subsidies to individual households have been ineffective. Community‐Led Total Sanitation (CLTS) is a revolutionary approach in which communities are facilitated to conduct their own appraisal and analysis of open defecation (OD) and take their own action to become ODF (open defecation‐free).

In six of the countries where CLTS has been spread – Bangladesh, India, Indonesia, Pakistan, Ethiopia and Kenya – approaches differ organisationally with contrasting combinations of NGOs, projects and governments.

Practical elements in strategies for going to scale have included: training and facilitating; starting in favourable conditions; conducting campaigns and encouraging competition; recruiting and committing teams and full‐time facilitators and trainers; organising workshops and cross‐visits; supporting and sponsoring Natural Leaders and community consultants; inspiring and empowering children, youth and schools; making use of the market and promoting access to hardware; verifying and certifying ODF status; and finding and supporting champions at all levels.

To spread CLTS well requires continuous learning, adaptation and innovation. It faces challenges. Paradigmatically, it requires major institutional, professional and personal shifts. Opposition at senior levels, pressures to disburse large budgets, demands to go to scale rapidly, and programmes to subsidise hardware for individual rural households, have been and remain threats and obstacles. Issues for review, reflection and research include: diversity, definition and principles; synergies with complementary approaches; scale, speed and quality; creative diversity; and physical, social and policy sustainability. In seeking constructive ways forward, four key themes or thrusts are: methodological development and action learning; creative innovation and critical awareness; learning and action alliances and networks, with fast learning across communities, districts and countries; and seeking to seed self‐spreading or light touch movements. A key to good spread is finding, supporting and multiplying champions, at all levels, and then their vision, commitment and courage.
Experimental Study on Performance of a Banded Structure Membrane Fuel Cell
Authors: Ejiri E. , Yamada K.
Published: June 2009

The basic performance of a banded structure membrane fuel cell module (rated power of 90W), which consisted of 15 polymer electrolyte membrane fuel cells laid out in a plane, was experimentally investigated. The results show that the module operated for a much longer time at an inclination angle, θ, of 90deg than at θ=0deg or 180deg, where it experienced a sudden power breakdown at the rated operating point. The output voltage and internal impedance of each cell in the module were specifically monitored over a long-term operation. Measurements were made of the temperature distribution of the entire module as well as of the oxygen concentration and relative humidity at a specific cell. Airflow near the cathode in a single cell was also visualized. It was concluded that the power breakdown was probably caused by flooding in the anode of one of the most downstream cells of the module.
A Numerical Investigation Into the Interaction Between Current Flow and Fuel Consumption in a Segmented-in-Series Tubular SOFC
Authors: Haberman B. A. , Marquis A. J.
Published: June 2009

A typical segmented-in-series tubular solid oxide fuel cell (SOFC) consists of flattened ceramic support tubes with rows of electrochemical cells fabricated on their outer surfaces connected in series. It is desirable to design this type of SOFC to operate with a uniform electrolyte current density distribution to make the most efficient use of the available space and possibly to help minimize the onset of cell component degradation. Predicting the electrolyte current density distribution requires an understanding of the many physical and electrochemical processes occurring, and these are simulated using the newly developed SOHAB multiphysics computer code. Of particular interest is the interaction between the current flow within the cells and the consumption of fuel from an adjacent internal gas supply channel. Initial simulations showed that in the absence of fuel consumption, ionic current tends to concentrate near the leading edge of each electrolyte. Further simulations that included fuel consumption showed that the choice of fuel flow direction can have a strong effect on the current flow distribution. The electrolyte current density distribution is biased toward the upstream fuel flow direction because ionic current preferentially flows in regions rich in fuel. Thus the correct choice of fuel flow direction can lead to more uniform electrolyte current density distributions, and hence it is an important design consideration for tubular segmented-in-series SOFCs. Overall, it was found that the choice of fuel flow direction has a negligible effect on the output voltage of the fuel cells.
Electrospun Nafion Nanofiber for Proton Exchange Membrane Fuel Cell Application
Authors: Bajon R. , Balaji S. , Guo S. M.
Published: June 2009

Proton exchange membrane fuel cells (PEMFCs) are attractive power plants for use in many applications, including portable power sources, electric vehicles, and on-site combined power/heat plants, due to the inherently high efficiency and low emission. The membrane electrode assembly (MEA) is the key component of a PEMFC. A standard five layer MEA consists of a proton exchange membrane, two catalyst layers, and two gas diffusion layers. The most commonly used electrolyte material is proton conductive perfluorinated sulfonic acid membrane, such as Nafion. Hydrogen is oxidized at the anode/electrolyte interface, the so-called triple-phase-boundary (TPB) active sites. TPB region must be a good electron conductor, a good ion conductor, and a porous structure for fuel/air diffusion. Typical PEMFC TPB is a porous structure made with Nafion and catalyst particle mixture. In this paper, electrospinning is used to synthesize polymer/Nafion nanofibers. Electrospinning is a straightforward method that has been successfully used to prepare fibers or fiber mats from a broad range of organic polymers. In the electrospinning process, a polymer solution held by its surface tension at the end of a capillary tube is subjected to an electric field, and as the electric field strength increases, a solid fiber is generated as the electrified jet is continuously stretched because of the electrostatic repulsions between the surface charges and the evaporation of solvent. Uniform one-dimensional Nafion nanofibers have been fabricated using Nafion solution and solutions containing polyvinyl pyrrolidone, polyethylene oxide, and polyvinyl alcohol. The morphologies of polymer/Nafion nanofibers, fabricated under different electrospinning conditions and different polymer compositions, are presented.
Investigation of Elastomer Graphite Composite Material for Proton Exchange Membrane Fuel Cell Bipolar Plate
Authors: Petrach Elaine , Abu-Isa Ismat , Wang Xia
Published: June 2009

The bipolar plate is an important and integral part of the proton exchange membrane (PEM) fuel cell and PEM fuel cell stacks. Currently bipolar plates represent more than 80% by weight and 40% by cost of the fuel cell stack. Traditional materials used for bipolar plates are primarily graphite and metal. Search for alternative materials to improve weight and cost considerations is needed. This paper discusses the results of an investigation of two elastomeric materials being developed for bipolar plate applications. Perceived advantages of the use of elastomers for this application include improved sealability without additional gasket material, reduction in the contact resistance between individual cells, improved formability, and weight reduction. The first elastomer investigated is a two component liquid silicone rubber, and the second is a polyolefin thermoplastic elastomer. These polymer matrix materials are made electrically conductive by the addition of conductive fillers including thermal graphite fibers (Cytec DKD & CKD), high surface area conductive carbon black nanoparticles (Cabot Black Pearls 2000), and graphite flakes (Asbury 4012). Electrical conductivity, processability, and elastic behavior measurements of the composites have been conducted. Some of silicone-graphite fiber composites material exhibit conductivity values comparable to those of the traditional graphite plate materials. Elasticity of all composites is maintained even at high filler concentrations.
Innovative Design of an Air-Breathing Proton Exchange Membrane Fuel Cell With a Piezoelectric Device
Authors: Ma Hsiao-Kang , Huang Shih-Han
Published: June 2009

This paper presents a three-dimensional transitional model to describe an innovative design for an air-breathing proton exchange membrane fuel cell (AB-PEMFC) with a microdiaphragm actuated by a piezoelectric device. This newly designed gas pump with a piezoelectric actuation structure is utilized as an air-flow channel in a proton exchange membrane fuel cell (PEMFC) system called PZT-PEMFC. When the actuator moves in the outward direction to increase the cathode channel volume, the air is sucked into the chamber: inward movement decreases channel volume and thereby compresses air into the catalyst layer and enhances the chemical reaction. The air-standard PZT-PEMFC cycle coupling with fuel∕air ratio is proposed to describe an air-breathing PZT-PEMFC. The model is able to simulate its major phenomena and performance in different fuel∕air ratio and PZT frequency. The results show that the PZT actuation leads to a more stable current output, more drained water, stronger suction, and overcome concentration losses at a proper PZT frequency.
Determination of an Empirical Transfer Function of a Solid Oxide Fuel Cell Gas Turbine Hybrid System Via Frequency Response Analysis
Authors: Tsai Alex , Banta Larry , Lawson Larry , Tucker David
Published: June 2009

This paper presents the study of the effect variations in the heat effluence from a solid oxide fuel cell (SOFC) has on a gas turbine hybrid configuration. The SOFC is simulated through hardware at the U.S. Department of Energy, National Energy Technology Laboratory (NETL). The gas turbine, compressor, recuperative heat exchanger, and other balance of plant components are represented by actual hardware in the Hybrid Performance Test Facility at NETL. Fuel cell heat exhaust is represented by a combustor that is activated by a fuel cell model that computes energy release for various sensed system states System structure is derived by means of frequency response data generated by the sinusoidal oscillation of the combustor fuel valve over a range of frequencies covering three orders of magnitude. System delay and order are obtained from Bode plots of the magnitude and phase relationships between input and output parameters. Transfer functions for mass flow, temperature, pressure, and other states of interest are derived as a function of fuel valve flow, representative of fuel cell thermal effluent. The Bode plots can validate existing analytical transfer functions, provide steady state error detection, give a stability margin criterion for the fuel valve input, estimate system bandwidth, identify any nonminimum phase system behavior, pinpoint unstable frequencies, and serve as an element of a piecewise transfer function in the development of an overall transfer function matrix covering all system inputs and outputs of interest. Further loop shaping techniques and state space representation can be applied to this matrix in a multivariate control algorithm.
Studying the Water Transport in a Proton Exchange Membrane Fuel Cell by Neutron Radiography and Relative Humidity Sensors
Authors: Chen Yong-Song , Peng Huei
Published: June 2009

Water management in a fuel cell is essential to ensure cell performance and life. In this study, a special single cell was designed for the purpose of detecting liquid water and water vapor simultaneously. The major difference between our design and traditional flow field designs is the fact that the anode and cathode channels were shifted sideways, so that they do not overlap in the majority of the active areas. The liquid water is measured by using neutron radiography located at the National Institute of Standards and Technology. The water vapor is measured by the 20 relative humidity sensors embedded in the anode and cathode flow field plates. The effects of the relative humidity and stoichiometry of the cathode inlet on relative humidity distribution in the channels and on water accumulation in the gas diffusion layers (GDLs) were investigated in this study. The liquid water accumulation at steady-state was calculated by using imaging mask techniques and least-squares method. The transient behavior of water transport was detected and recorded when a step load change was applied on the cell. It is demonstrated that liquid water tends to accumulate in the gas diffusion layers under the rib. Moreover, the transient behavior of liquid water transport in the GDL and the relative humidity distribution in both the anode and cathode channels at different operating conditions are discussed.
Putting a Charge in Healing: Electrical Stimulators Show Great Promise, Especially for Spinal Fusions
Authors: Schenberger Deborah
Published: June 2009

Spinal fusion is the latest application of electrical stimulation as a fracture healing. This exciting new application has been proven over 30 years of use, and the market is now poised for rapid growth. Patent activity shows an increased interest in this technology, and both start-up companies and orthopedic giants can thus benefit from introducing new products in this field.
Experimental and Numerical Study of a Sutured Tendon Under Tensile Loading
Authors: Chizari Mahmound , Reading Jonathan , Wang Bin
Published: June 2009

This paper presents an experimental and numerical method for investigating the biomechanics of soft tissue sutured tendons. The aim is to achieve a better understanding of the mechanics of a sutured tendon applicable to tendon injury.
Knee Replacement Simulation Including Large Displacement and Viscoelastic Effects
Authors: Fahlgren Eric , Elliott Andrew , Carlson Mark
Published: June 2009

Human total joint replacement has become a common place procedure in the past decade, principally to eliminate pain in patients affected by osteoarthritis of the knee, hips, shoulder and spine. While in the past, this was done mostly for older patients with reduced mobility, more recently these replacements are being done for much younger, much more active people. As a result, the artificial joints need larger ranges of motion and are subject to much higher loads, while being required to last longer in place.
System Development and Testing of a Liquid Needle-Free Injector
Authors: Chen Kai , Lv Yonggui
Published: June 2009

A simple approach is presented to determine several critical parameters of a liquid needle-free injector. A jet injector system was developed based on the approach, and its jet characteristics were tested.
A Micromachined Device Using Transient Hot-Wire Method for High Accuracy Thermal Conductivity Measurement of Semi-Rigid Materials
Authors: Liang Xin , Ding Weiping , Shu Zhiquan , Zhou Xiaoming , Gao Dayong
Published: June 2009

Based on the transient hot-wire method and well developed microfabrication techniques, a new thermal sensor, in which the microfabricated gold wire serves as both a heater and a thermometer, has been developed for measuring the thermal conductivities of semi-rigid materials. The intention that only one calibration constant is needed for an entire batch of sensors has been validated. Thermal conductivities of distilled water, ethylene glycol, dimethyl sulfoxide (DMSO), and apple at different temperatures have been obtained. Measurements are in agreement with suggested values. Complete results will be presented at the conference. The operating temperature of 0°C to 27°C has been tested and is anticipated to be −20°C to 60°C. In spite of conventional advantages, the presented sensor offers new exciting superior performance characteristics, such as reduced thermal resistivity and higher sensitivity, easier manufacturing for mass production, flexibility to reconfigure the sensor for samples with various sizes and shapes, and much reduced workload for system calibration.
Technique and Device of Irregular Osseointegration Detection for Dental Implant
Authors: Pan M.-Ch. , Chen Z.-W. , Zhuang H.-B. , Lee S.-Y.
Published: June 2009

This paper aims to develop detection techniques and associated devices on irregular osseointegration during and after dental implant operations. More specifically, the study relates to the quantitative evaluation of an osseointegration between a dental implant and an alveolar bone through examining differences of dynamic characteristics of the dental implant and irregular bone defects. Developed techniques are able to inspect quantity, orientation and depth of bone defect. The associated device to this purpose is designed based upon the application of acoustic induced excitation and vibration response.
The PediaFlow Pediatric Ventricular Assist Device
Authors: Paden Brad E. , Wu Jingchun , Noh Myounggyu D. , Paden Dave , Ricci Michael , Snyder Shaun , Maul Timothy M. , Webber Steven , Shu Fangjun , Verkaik Josiah , Khanwilkar Pratap , Boston J. Robert , Antaki James F. , Keller Bradley B. , Kameneva Marina V. , Borovetz Harvey S.
Published: June 2009

This paper describes a design process for a new pediatric ventricular assist device (VAD), the PediaFlow. The VAD is a magnetically levitated turbodynamic pump design for chronic support of infants and small children. The design entailed the consideration of multiple pump topologies, from which an axial mixed-flow configuration was chosen for further optimization via computation fluid dynamics. The magnetic design includes permanent-magnet (PM) passive bearings for radial support of the rotor, an actively controlled thrust actuator for axial support, and a brushless DC motor for rotation. These components are closely coupled both geometrically and magnetically, and were therefore optimized in parallel, using electromagnetic, rotordynamic and fluid models. Multiple design objectives were considered including efficiency, size, and margin between critical speed to operating speed. The former depends upon the radial and yaw stiffnesses of the PM bearings. Analytical expressions for the stiffnesses were derived and verified through FEA. A toroidally-wound motor was designed for high efficiency and minimal additional negative radial stiffness. The design process relies heavily on optimization at the component-level and system-level. The results of this preliminary design optimization yielded a pump design with an overall stability margin of 15 percent, based on a pressure rise of 100 mmHg at 0.5 lpm running at 16,000 RPM.
Packaging of Biomedical Devices: A Critical Aspect in Its Performance
Authors: Everaerts Frank
Published: June 2009

Biomedical device development and (bio)material selection primarily for its casing go hand in hand. Traditionally “inert” materials were selected for surfaces in contact with tissue structures. Also a large number of surface treatment processes have been developed in order to increase the biocompatibility. With these technologies in hand, a broad range of materials can be selected.
PO2 and PCO2 Measurements for the Prevention and Early Detection of Anastomotic Leakage
Authors: Tanase D. , Tang K. , French P. J. , Komen N. , Kleinrensink G. , Jeekel J. , Lange J. F. , van Veen J. J. , Draaijer A.
Published: June 2009

Anastomotic leakage is the main, yet unsolved reason for mortality in abdominal surgery. Every year patients die because of anastomotic leakage after surgery. In the case of colorectal surgery, statistics show an incidence rate of 10–13% and a mortality rate of 32%. The aim of this work is to reduce the complications by improving the feedback to the surgeon during the operation and to minimise the fatalities by developing an early warning system. Currently, there are no peroperative methods to avoid anastomotic leakage or any validated early postoperative parameters for leakage detection. Therefore, an objective aid to detect leakage during surgery and recovery is of utmost importance.
Geometrical Models of Vertebral Arteries and Numerical Simulations of the Blood Flow Through Them
Authors: Jozwik Krzysztof , Obidowski Damian
Published: June 2009

Vertebral arteries are a system of two blood vessels through which blood is carried to the rear region of the brain. This region of the human body has to be very well supplied with blood, without any breaks or deficiencies in the blood flow. Blood is delivered to the brain through carotid arteries as well. All these arteries are connected to the circle of Willis, which has to fulfill all demands of the human brain as far as the blood flow is concerned. However, vertebral arteries due to their position and shape are a special kind of blood vessels. They originate at various distances from the aortic ostium, may branch off at different angles, have various length, inner diameter and spatial shape. Three different geometries of vertebral arteries, which most frequently occur in the human body structure, have been chosen, and for each twenty five various combinations of artery inner diameters have been used to generate 3D models of these arteries. For seventy five different models thus created, the numerical simulations have been performed. The results obtained have indicated explicitly that differences in the flow and instantaneous velocity values in vertebral arteries and in the point they join to form the basilar artery do not result from pathological changes in the artery system, but may follow from physical phenomena that occur in arteries as a consequence of the pulsating character of the flow and the unique geometry, which is related to the individual human anatomical structure.
Design of a Navigational Aid for Colonoscopy
Authors: Gavalis Robb M. , Xing Hua , Wong Peter Y. , Lilge Lothar , Cao Caroline G. L.
Published: June 2009

Colonoscopy is currently the gold standard for diagnosing colorectal cancer and inflammatory bowel disease. During a colonoscopy, a flexible endoscope is inserted into the patient’s colon to inspect the inner wall of the large intestine, from the rectum to the caecum. This procedure is very important for cancer screening and can yield early diagnosis. Colon cancer is 85–95% successfully treated if detected early; however, there is only a 30% compliance rate for the procedure in the United States. This low compliance rate for the examination is largely due to its uncomfortable nature, caused by difficulties in blind scope manipulation, and “looping” of the endoscope which can lead to stretching and perforation of the bowel [1] (Figure 1).
An Assessment of the Strength Characteristics of Button Type Facet Fusion Grafts
Authors: Pfeiffer Ferris M. , Abernathie Dennis L.
Published: June 2009

Back pain is one of the most widespread sources of chronic pain in the human population. The etiology of back pain is nearly as diverse as the treatment measures used to alleviate the discomfort. However, when conservative options have been exhausted, without achieving adequate relief, the patient and physician often turn to surgical options to eliminate the source of pain.
Development of a Controlled Rate Cooling System for Cryopreservation
Authors: Chen Hsiuhung , Shu Zhiquan , Gao Dayong
Published: June 2009

Cooling rate is one of the most critical factors affecting the survival of cells during cryopreservation. A novel box-in-box device has been developed for use in the cryopreservation of human hematopoietic stem cells (HSCs). This work presents the comparison of experimentally observed thermal profiles for two different setups and, in the near future, cryopreservation survival rates of live cells accordingly. In experiments, using a simple protocol with a −80°C freezer, the box-in-box device is used to: (1) achieve an average cooling rate of −1°C/min with polyethylene insulation layers on both sides, and (2) achieve an average cooling rate of −2°C/min with a polyethylene insulation layer on one side and by having the other side directly contacted to the outermost aluminum case, both from room temperature to −40°C. The concept that utilizes thermal inertia of materials may be readily adapted to other cooling rates to support cryopreservation of a wide array of tissues and cells. It is concluded that the box-in-box system can be developed into a cost-effective, durable and reliable device for the cryopreservation of HCSs.
In Vitro Testing of Living Aortic Heart Valves Using a Pulsatile Bioreactor
Authors: Sierad Leslie N. , Simionescu Dan
Published: June 2009

Valvular heart disease results in approximately 275,000 valve replacement procedures performed annually worldwide. Structural deterioration, calcification, tissue overgrowth, and thromboembolism frequently lead to abnormal tissue stiffness levels that contribute to the failure of native heart valves. While many treatment alternatives exist, understanding the factors that regulate the activity of heart valve cells is critical for circumventing pathological heart valve fibrosis and engineering improved biologically active heart valve replacements.
The Influence of Renal Branches on the Iliac Arteries Blood Flow
Authors: Carneiro Filipa , Silva Ana E. , Teixeira Senhorinha F. C. F. , Teixeira Jose´ C. F. , Lobarinhas Pedro A. M. , Ribeiro Vasco G.
Published: June 2009

The characterization of blood flow is important to establish links between the hemodynamics and the occurrence of cardiovascular diseases. This study describes the development of a 3-D computational model able to predict the blood flow along the abdominal aorta, including the renal and iliac branches. Upstream branches in the abdominal aorta lead to more complex flow patterns downstream, intensifying reverse and asymmetric flow patterns. The focus is on the occurrence of reverse flow and the perturbations in blood flow patterns originated by the branches. Results show regions of recirculation in the walls of the abdominal aorta, renal and iliac branches. It is concluded that, the renal branches induces perturbations in blood flow and result in asymmetric velocity profiles.
A Computational Approach to Bone Remodeling Postoperative to Facet Fusion
Authors: Pfeiffer Ferris M. , Abernathie Dennis L.
Published: June 2009

The mechanical and biologic factors that drive bone fusion can be better understood. This is evident in the fact that of the approximately 200,000 spine fusion procedures performed each year failure to achieve a bony union can occur in as many as 40% of the cases (Boden 2002). Advances in computational methods and mathematical modeling of bone fusion make it advantageous to use numerical methods such as the finite element method, to better understand bone remodeling mechanics.
A Polymer MEMS 2-Axis Scanning Mirror Driven by Magnetic Force
Authors: Lai Zhian , Gunn Nicholas , Bachman Mark , Li Guann-Pyng
Published: June 2009

Light scanning device has many applications and is causing a lot of interest. Optical coherence tomography (OCT) is one example of its application in the field of biomedical imaging. With the trend of miniaturization of biomedical devices, miniaturized light scanning devices are desired for applications like compact OCT system [1].
Rotational Scanning Mechanism of Multi-Point Synchronous Detection for Near Infrared Diffuse Optical Tomography
Authors: Pan Min-Chun , Chen Chien-Hung , Chen Lian-Yu , Pan Min-Cheng
Published: June 2009

This study aims at the design, implementation, and verification of a near infrared (NIR) diffuse optical tomography (DOT) electro-optical imaging system based on a measuring instrument with scanning mechanism of synchronous multi-point detection and an image reconstruction scheme implemented on an off-line PC. The developed measurement instrument possesses a high degree of angular resolution and can be operated in a continuous-intensity or intensity modulation scheme to acquire output NIR radiance signals. Experimental trials are conducted using both homogeneous and heterogeneous phantoms made of high-scattering Intralipid. Promising results have been obtained with a superior spatial resolution, especially for absorption image, compared with the system with fixed number of detection channels.
An Integrated Software and Hardware System for Dynamic Cadaveric Shoulder Testing
Authors: Hoopes Daniel M. , Seibert Scott B. , Lee Thay Q.
Published: June 2009

Shoulder joint biomechanics can be investigated using cadaveric testing setups. A novel system is described which uses a computer and graphical user interface to both control electronic actuators and record data from sensors. The algorithm of the custom software, programmed in the LabVIEW G language, is described. A desktop computer running the custom software and through National Instruments I/O hardware gives users full control over dynamic and static actuation and also collects, compiles, and records all data streams from disparate sensing modalities. Data gathered from a run to validate the system is also presented.
Biomimetics Microfluidic Tactile Sensor Array
Authors: Tseng Wei-Yu , Fisher Jefferey S. , Prieto Javier L. , Rinaldi Kentaro , Lee Abraham P.
Published: June 2009

Tactile sensors are the interfaces to detect the physical properties of objects and have extensive applications in robotic sensing, biomechanics, minimally invasive surgery and human prosthetics [1]. For human prosthetics applications, the current prosthetic hand can offer only the manipulation function. With the sensing being part of the prosthetic hand, the user can get feedback from the prosthetic. This feeling can help users decrease their dependency on visual information and have better body control on weight balancing and signal limb stance.
Kinematics of Rotating Platform Total Knee Replacements: Does the Position of the Rotating Platform Axis Matter?
Authors: Williams John L. , Gomaa Said T.
Published: June 2009

We analyzed the kinematics of two rotating platform total knee replacement designs using KneeSIM, a commercially available computer code (LifeModeler, San Clemente, CA) in which we could manipulate the location of the axis of rotation of the rotating bearing.
Noninvasive Blood Flow Imaging for Real-Time Feedback During Laser Therapy of Port Wine Stain Birthmarks
Authors: Huang Yu-Chih , Tran Nadia , Nelson J. Stuart , Choi Bernard
Published: June 2009

Port wine stain (PWS) birthmarks are progressive vascular malformations that occur in ∼12,000 live births per year in the United States. The majority (∼90%) of PWS birthmarks occur on the head and neck regions, and thus are difficult to conceal. The psychosocial development of individuals with PWS birthmarks is adversely affected. Facial PWS lesions have been associated with increased incidence of glaucoma and seizures. The progressive nature of PWS skin may be due to lack of neuronal regulation of blood vessel size. Progressive development of the PWS results in a darker appearance, soft tissue hypertrophy, nodularity, and overall further disfigurement. Current treatment options have significant limitations in terms of efficacy and risk. With laser therapy, a reduction in size and degree of redness of PWS skin occurs in ∼60% of treated patients. After ten treatment sessions, complete disappearance of the PWS occurs in only ∼10% of treated patients. To reduce the financial burden and potential risks of repeated treatments under general anesthesia, there is a need for innovative, personalized methods to maximize the reduction in PWS redness per treatment session. Without addressing this need, the overall efficacy of PWS laser therapy will remain variable, because treatment protocols will remain based primarily on the subjective impression and overall experience of the treating surgeon. To address this need, we propose use of laser speckle imaging (LSI) to provide real-time, quantitative feedback during laser surgery.
Implantable Minipump With MEMS Electrothemal Valve for Bolus Injection in Mice
Authors: Givrad T. K. , Maarek J.-M. I. , Li P. Y. , Meng E. , Sardesai N. , Holschneider D. P.
Published: June 2009

An implantable, single-use miniature infusion pump (MIP) was designed to allow radiotracer injection and functional neuroimaging in freely moving mice. The pump comprises a pressurized reservoir, and a parylene electrothermal valve, which opens to inject tracer through an intravenous catheter into the circulation. A 3-layer 300 μl elastomeric reservoir was built by molding silicone in two-part metal casts. The valve was powered by inductive power transfer from an external 20 cm diameter primary coil to an implanted miniature 8-turn, 1.6 cm diameter Litz-wire secondary coil capable of generating 150 mW at the frequency of 2 MHz.
An Improved External Fixator Design for Femoral Fracture Reduction
Authors: LeBlon Courtney E. , Rahimi Nima S. , Cucinotta Michael J. , Paliwal Manish
Published: June 2009

The use of external fixator for femoral shaft fixators in children has been a device of choice. The use though satisfactory, the occurrences of wire/ pin tract infections has been widely reported. Moreover, the use of Ilizarov external fixator in adults has been limited due to its bulk. Hence there is a need for improvement on the current external fixators for femoral fractures. The objective of the study is to design an external fixator for femoral fracture reduction with improved angulation and adjustability, reduced bulk, and comparative stiffness.
A Steady-State Model of Mass Transfer for Removing Cryoprotective Agents From Cryopreserved Blood With Hollow Fiber Modules
Authors: Ding Weiping , Shu Zhiquan , Zhou Xiaoming , Kang Xianjiang , Gao Dayong
Published: June 2009

A steady-state model coupling mass transfer across cell and fiber membranes is theoretically developed to investigate the removal process of cryoprotective agents (CPAs) from cryopreserved blood with hollow fiber modules, and then CPA concentration variation and cell volume response are studied.
Polymer-Based Sensors for Dynamic Intravascular Shear Stress Analysis
Authors: Ai Lisong , Yu Hongyu , Rouhanizadeh Mahsa , Takabe Wakako , Meng Ellis , Kim E. S. , Hsiai Tzung
Published: June 2009

This paper describes a polymer-based shear stress sensor built on catheter for in vivo measurements and potential application in atherosclerosis diagnosis. MEMS shear stress sensor with backside wire bonding has been used to address in vitro applications for micro-scale hemodynamics with high temporal and spatial resolution. However, to assess shear stress in the tortuous and dynamic arterial circulation, we had to develop a new generation of polymer- and catheter-based sensors that are both flexible and deployable. The individual sensor was packaged near the tip of a catheter for intravascular shear stress analysis. The wire bonding and electrode leads were insulated by a film of Parylene C and were connected to the external circuit along the guide-wire. The sensor was deployed through the catheter into the aorta of New Zealand White (NZW) rabbits by the femoral cut-down procedure. Based on the heat transfer principle, the device was able to detect small temperature perturbation in response to the pulsatile flow at ∼200 beats/minutes in the rabbits. The sensor was calibrated in the presence of rabbit blood flow at 37.8°C. We demonstrated the feasibility of translating a polymerbased device for dynamic intravascular measurement with a potential for clinical applications in detecting coronary artery disease and stroke.
Engineering Design Controls for Efficient Medical Device Development
Authors: Henn Lisa
Published: June 2009

Early stage medical device development teams investigate many alternatives before selecting a final design proposal. The team must be able to retrace and reproduce successful designs and understand factors that underpin decisions that came before. This is especially important in a university setting due to the natural turnover on the team that is inherent in a successful research group. Effective design control provides this support to the design team.
Quantitative Near Infrared Imaging of Skin Flaps
Authors: Durkin Anthony J. , Kim Jae G. , Cuccia David J.
Published: June 2009

We present a wide-field, near infrared spectral imaging modality called modulated imaging (MI) that shows great promise for quantitatively imaging superficial (1–5 mm depth) tissues. We have applied this method to a dorsal pedicle skin flap model to determine in-vivo local concentrations of oxy- and deoxy-hemoglobin and water.
System for Recording the Bowel Sounds of Premature Infants
Authors: Hill Jonathan M. , Regan M. Shalane , Adrezin Ronald S. , Eisenfeld Leonard
Published: June 2009

Premature infants receive enteral feedings well before the time they would have if they remained in utero. The alimentary system may or may not be receptive to nutrition. Neonatal caretakers must decide whether it is safe to feed the patient. Possible etiologies of bowel dysfunction include bowel obstruction, functional or anatomic which may be reflected as an abnormality or lack of peristalsis. This peristalsis may be monitored acoustically to determine the health of the patient’s digestive tract.
Flexible Wireless Research Oriented System for Human Performance Studies
Authors: Hill Jonathan M. , Atallah Majdi , Ball Kevin
Published: June 2009

The availability of low-cost field programmable gate arrays (FPGAs) and wireless technologies provides new opportunities for the development of a wearable computing platform for human performance research. Our goal is a flexible research platform that is configurable for a number of sensor types, provides various options for information processing, and is useful in various simple protocols. This dynamic monitoring device will enable further investigations of the feasibility of use in clinical research and practice settings.
Multi-Dimensional Transfer Functions for Tissue Selection in Computed Tomography
Authors: Meyer Joerg , Nguyen Huan T.
Published: June 2009

Computed Tomography (CT) is a widely used 3-D imaging technique. A 3-D volumetric grid is obtained from 2-D cross-sectional images. In order to be useful as a diagnostic tool, voxel-based numerical values that represent X-ray absorption in each voxel must be interpreted and combined to form an image that depicts tissue composition at a particular location. Transfer functions are used to translate measured X-ray absorption data into Hounsfield units, and Hounsfield units into intensities, colors and transparency values. Gradient-based transfer functions are used to highlight material boundaries and interfaces between different tissues. Multi-dimensional transfer functions combine the advantages of regular and gradientbased transfer functions, facilitating a wide spectrum of visual representations. Transfer functions are usually under user control and often difficult to find. Improper transfer functions can create misleading visualizations and may lead to erroneous diagnoses. This article discusses how multi-dimensional transfer functions can be derived that are clinically relevant and meaningful.
A Dual Modality Dynamic Imaging System
Authors: Unlu Mehmet Burcin , Lin Yuting , Nalcioglu Orhan , Gulsen Gultekin
Published: June 2009

Diffuse optical tomography (DOT) is a recently emerging technique that uses arrays of sources and detectors to obtain spatially dependent optical parameters of tissue. DOT techniques have been applied for a wide range of applications, especially for breast and head as well as animal imaging. We have developed an integrated dynamic MR/DOT imaging system. This combined system can acquire MR and optical data simultaneously with a high temporal resolution. Hence, the enhancement kinetics of multiple MR and optical contrast agents can be monitored independently.
Articular Contact Estimation by Surface Reconstruction Based on True Geometry
Authors: Jun Bong-Jae , Lee Thay Q.
Published: June 2009

The intra-articular contact characteristics of the diarthrodial joints have been measured by using Fuji pressure sensitive films and a Tekscan sensor system. Direct measurement can only provide resultant contact information. Indirect contact estimation methods, such as mathematical modeling or a stereophotogramametric method can be used to estimate contact kinematics on each articulating surface. However, indirect estimation methods are often based on simplified geometry due to limited accuracy or simplification, resulting in erroneous contact estimation. The objective of this study was to quantify the intra-articular contact area and shape of the glenohumeral joint determined by surface reconstruction. The results showed that the contact estimation method using surface reconstruction was in good agreement with the results of Tekscan measurement (accuracy ≤ 5.3% and repeatability ≤ 11.2%). The contact estimation method may provide a valuable avenue for understanding contact kinematics in human diarthrodial joints.
The State of Permanganate With Relation to In Situ Chemical Oxidation
Authors: Veronda Brenda , Dingens Matthew
Published: June 2009

In Situ Chemical Oxidation (ISCO) with permanganate had its beginnings over 10 years ago. Since that time, many sites have been successfully treated for organic compounds including chlorinated ethenes (perchloroethylene, trichloroethylene, etc.) phenols, explosives such as RDX, and many other organics. The successful application of ISCO with permanganate requires the integration of many site-specific factors into the remedial design. ISCO with permanganate is an effective technology, not only for its oxidative properties and persistence, but also for its application flexibility to remediate soil and groundwater. The merits of any type of treatment technology can be assessed in terms of effectiveness, ease of use, reaction rate, and cost. The use of permanganate for in-situ chemical oxidation results in the complete mineralization of TCE and PCE and can result in treatment levels below detection limits. Permanganate is a single component oxidizer, which is easily handled, mixed and distributed to the subsurface. Permanganate is also inexpensive to design and implement as compared to other technologies. This presentation will provide a general overview of the application and safety aspects of ISCO with permanganate. This paper will discuss the advantages and limitations of this technology, typical cost ranges, site evaluation and application technologies.
Nuclear Waste Treatment: Studying the Mixed Ion Type Effects and Concentration on the Behaviour of Oxide Dispersions
Authors: Omokanye Qanitalillahi , Biggs Simon
Published: June 2009

In order to gain good control over a particulate dispersion it is necessary to accurately characterise the strength of interparticle forces that may be operating. Such control is not routinely used, as yet, in the nuclear industry despite the possible benefits. We are investigating the impact of mixed electrolyte systems, for example NaCl and Na2SO4, on the stability of oxide simulant particle dispersions. The electroacoustic zeta potentials and shear yield stresses for concentrated dispersions have been measured across a range of pH conditions and electrolyte concentrations (0.001 M – 1.0 M). This paper summarizes initial data from these studies showing how the shear yield stress of concentrated aqueous oxide particle dispersions, can be adjusted through regulation of pH and the addition of background electrolytes (salt). The yield stress as a function of pH for these dispersions in mixed electrolytes showed a direct correlation with corresponding measurements of the zeta potential. Changes in the background electrolyte concentration or type were seen to cause a shift in the position of the isoelectric point (iep). Measurements of the shear yield stress showed a maximum at the iep corresponding to the position of maximum instability in the suspension. The consequences of these data for the efficient treatment of solid-liquid systems will be discussed.