Biomedical Engineering and Bioengineering Commons^™

Molecular Dynamics Simulation Of Fractal Aggregate Diffusion, Gaurav Pranami, Monica H. Lamm, R. Dennis Vigil

R. Dennis Vigil

The diffusion of fractal aggregates constructed with the method by Thouy and Jullien [J. Phys. A 27, 2953 (1994)] comprised of Np spherical primary particles was studied as a function of the aggregate mass and fractal dimension using molecular dynamics simulations. It is shown that finite-size effects have a strong impact on the apparent value of the diffusion coefficient (D), but these can be corrected by carrying out simulations using different simulation box sizes. Specifically, the diffusion coefficient is inversely proportional to the length of a cubic simulation box, and the constant of proportionality appears to be independent of …

Optochemical Nanosensors For Intracellular Chemical Measurement, Raoul Kopelman, Michael T. Miller, Murphy Brasuel, Heather Clark, Marion Hoyer, Martin Philbert

Heather Clark

The development of a submicron optical fiber "supertip" has provided advantages over previously produced submicron tips, such as facilitating insertion of these sensors into cells while minimizing damage to the cell membrane. Fiber optic ion correlation-based nanosensors for sodium, potassium and chloride employing these "supertips" have been applied to the monitoring of ion concentrations in single mouse oocytes. These sensors have also been used to monitor the effect of an ion channel-blocking agent. In order to address the challenge associated with single-cell simultaneous measurement of multiple analytes, the use of submicron optical fiber multiprobes has been explored.

Novel Optical Biosensors Using A Gold Colloid Monolayer Substrate, Heather Clark, Greg Merritt, Raoul Kopelman

Heather Clark

A novel optical biosensor matrix has been developed to exploit the native fluorescence of certain proteins. This matrix uses a gold colloid monolayer attached to an end of a fiber as a substrate for protein attachment. The effect of the gold monolayer size has been investigated through the techniques of fluorescence, scanning electron microscopy, and transmission electron microscopy. It has been shown that the size ofthe gold colloid does produce a marked difference in the fluorescence intesity measured. It is surmised through the use of microscopy techniques that the intensity changes seen in the fluorescence emission are not a result …

Second-Harmonic Imaging Microscopy Of Living Cells, Paul J. Campagnola, Heather Clark, William A. Mohler, Aaron Lewis (Prof.), Leslie M. Loew

Heather Clark

Second harmonic generation (SHG) has been developed in our laboratories as a high-resolution nonlinear optical imaging microscopy for cellular membranes and intact tissues. SHG shares many of the advantageous features for microscopy of another more established nonlinear optical technique: two-photon excited fluorescence (TPEF). Both are capable of optical sectioning to produce threedimensional images of thick specimens and both result in less photodamage to living tissue than confocal microscopy. SHG is complementary to TPEF in that it uses a different contrast mechanism and is most easily detected in the transmitted light optical path. It can be used to image membrane probes …

A Comparative Study Of Optical Fluorescent Nanosensors ("Pebbles") And Fiber Optic Microsensors For Oxygen Sensing, Z. Chen-Esterlit, S. F. Peteu, Heather Clark, W. Mcdonald, R. Kopelman

Heather Clark

In this paper we report the use of phase sensitive fluorometry to obtain preliminary results from opto-chemical fluorescent oxygen nanosensors. PEBBLE (Probe Encapsulated By Biologically Localized Embedding) sensors were fabricated by immobilizing tris(4,7-diphenyl—1, 10-phenanthroline)Ru(II) chloride and tris(1,10-phenanthroline)Ru(II) chloride within a polyacrylamide matrix. PEBBLEs have diameters of 20-200 nm and exhibit excellent performance for dissolved oxygen detection. Their performance is compared with micrometer-sized (10-20 μm) optical fiber sensors and free dye in solution. Oxygen sensing ability of PEBBLEs was tested in the presence of other quenchers and compared with free dyes in solution. While PEBBLEs have been developed for minimally invasive …

Sub-Wavelength Plasmonic Readout For Direct Linear Analysis Of Optically Tagged Dna, Jonathan Varsanik, William Teynor, John Leblanc, Heather Clark, Jeffrey Krogmeier, Tian Yang, Jonathan Bernstein

Heather Clark

This work describes the development and fabrication of a novel nanofluidic flow-through sensing chip that utilizes a plasmonic resonator to excite fluorescent tags with sub-wavelength resolution. We cover the design of the microfluidic chip and simulation of the plasmonic resonator using Finite Difference Time Domain (FDTD) software. The fabrication methods are presented, with testing procedures and preliminary results. This research is aimed at improving the resolution limits of the Direct Linear Analysis (DLA) technique developed by US Genomics. In DLA, intercalating dyes which tag a specific 8 base-pair sequence are inserted in a DNA sample. This sample is pumped though …

Biomechanical Investigation Of A Novel Ratcheting Arthrodesis Nail., Kristen Billiar, Jeremy Mccornick, Xinning Li, Douglas Weiss, John Wixted

Kristen L. Billiar

Background: Knee or tibiotalocalcaneal arthrodesis is a salvage procedure, often with unacceptable rates of nonunion. Basic science of fracture healing suggests that compression across a fusion site may decrease nonunion. A novel ratcheting arthrodesis nail designed to improve dynamic compression is mechanically tested in comparison to existing nails. Methods: A novel ratcheting nail was designed and mechanically tested in comparison to a solid nail and a threaded nail using sawbones models (Pacific Research Laboratories, Inc.). Intramedullary nails (IM) were implanted with a load cell (Futek LTH 500) between fusion surfaces. Constructs were then placed into a servo-hydraulic test frame (Model …

Silver Nanosphere Sers Probes For Sensitive Identification Of Pathogens, Kyuwan Lee

Kyuwan Lee

The identification and timely detection of pathogenic bacteria is critical to ensuring safe food, health, and water. Although surface enhanced Raman scattering (SERS) methods have been used for pathogen characterization and single molecule sensing, the challenge of detecting pathogens in very low numbers using an optimal substrate that is sensitive and reproducible is still a challenge. In this report, we have developed and explored a novel SERS active substrate of 60−80 nm diameter through the assembly of Ag nanocrystals (AgNCs) into Ag nanospheres (AgNSs). A finite difference time domain (FDTD) analysis of the electromagnetic field produced by these structures and …

Femur Flap For Tibial Reconstruction: Percent Circumference Required To Convey A Mechanical Advantage Over The Fibula, Kristen Billiar, Genevieve Broderick, Janice Lalikos, Matthew Chowaniec, Meghan Collins, Elias Wilson, Russell Babbitt, Julie O'Brien, Raymond Dunn

Kristen L. Billiar

The fibula flap is commonly used to reconstruct the tibia. This has risk of postoperative fracture despite long-term non-weight bearing. A flap using noncircumferential distal femur is proposed. This study is to determine the circumference of femur required to produce greater strength than the fibular flap. Femurs and fibulas were harvested from eight cadavers. The structural strength of fibula and femur flaps was assessed using three-point bend. Compression testing was performed on osteotomized and whole femurs to assess donor site morbidity. The 35% flap (mean maximum force at fracture 869 N) was not significantly stronger than the fibula flap (626 …

Dynamic Simulation Of Movement Based On Opensim And Matlab/Simulink, M. B. Mansouri, Jeffrey A. Reinbolt

Jeffrey A. Reinbolt

No abstract provided.

Computational Vascular Fluid–Structure Interaction: Methodology And Application To Cerebral Aneurysms, Y. Bazilevs, Ming-Chen Hsu, Y. Zhang, Z. Wang, T. Kvamsdal, S. Hentschel, J. G. Isaksen

Ming-Chen Hsu

A computational vascular fluid–structure interaction framework for the simulation of patient-specific cerebral aneurysm configurations is presented. A new approach for the computation of the blood vessel tissue prestress is also described. Simulations of four patient-specific models are carried out, and quantities of hemodynamic interest such as wall shear stress and wall tension are studied to examine the relevance of fluid–structure interaction modeling when compared to the rigid arterial wall assumption. We demonstrate that flexible wall modeling plays an important role in accurate prediction of patient-specific hemodynamics. Discussion of the clinical relevance of our methods and results is provided.

Minimizing Valgus Knee Loading During Sidestepping: Implications For Acl Injury Risk, C. J. Donnelly, D. G. Lloyd, B. C. Elliott, Jeffrey A. Reinbolt

Jeffrey A. Reinbolt

No abstract provided.

Pre-Swing Deficits In Forward Propulsion, Swing Initiation And Power Generation By Individual Muscles During Hemiparetic Walking, Carrie Peterson, Allison Kinney, Stephen Kautz, Richard Neptune

Allison Kinney

No abstract provided.

Posture Influences Ground Reaction Force: Implications For Crouch Gait, H. X. Hoang, Jeffrey A. Reinbolt

Jeffrey A. Reinbolt

No abstract provided.

Improving Computed Muscle Control Through Optimization To Generate Dynamic Simulations Of Overground Running, Jeffrey A. Reinbolt, C. J. Donnelly

Jeffrey A. Reinbolt

No abstract provided.

A New Multilayer Composite With Functionally Graded Design For Endodontic Application., Ahmed A. Madfa

Ahmed A. Madfa

Multilayer composite with FG structure were fabricated using zirconia (ZrO), alumina (AI2O3), Hydroxyapatite (HA) and titanium (Ti) micropowders. Powder selection and their combination in each layer were according to the results of finite element analysis.

Determination Of Material Emission Signatures By Ptr-Ms And Their Correlations With Odor Assessments By Human Subjects, Kwanghoon Han

Kwanghoon Han

The objectives of this study were to determine volatile organic compound (VOC) emission signatures of nine typical building materials by using proton transfer reaction-mass spectrometry (PTR-MS) and to explore the correlation between the PTR-MS measurements and the measurements of acceptability by human subjects. VOC emissions from each material were measured in a 50-l small-scale chamber. Chamber air was sampled by PTR-MS to determine emission signatures. Sorbent tube sampling and TD-GC/MS analysis were also performed to identify the major VOCs emitted and to compare the resulting data with the PTR-MS emission signatures. The data on the acceptability of air quality assessed …

Antimicrobial And Antioxidant Activities Of Essential Oil And Methanol Extract Of Jasminum Sambac From Djibouti, Fatou Abdoul-Latif, Prosper Edou, François Eba, Nabil Mohamed, Adwa Ali, Samatar Djama, Louis-Clément Obame, Mamoudou Hama Dicko

Pr. Mamoudou H. DICKO, PhD

The essential oil of jasminum sambac from Djibouti was subjected to screening for their possible antioxidant activity by two complementary test systems, namely DPPH free radical scavenging and beta-carotene-linoleic acid assays. Butylated hydroxytoluene (BHT) was used as positive control in both test systems. In the DPPH test system, the IC50 value of essential oil and methanol extract were respectively 7.43 and 2.30 μg/ml. In the beta-carotene-linoleic acid system, oxidation was effectively inhibited by Jasminum sambac, the RAA value of essential oil and methanol extract were respectively 96.6 and 93.9%. When compared to BHT, the essential oil and methanol extract had …

Homotopy Perturbation Algorithm Using Laplace Transformation, Mohammad Madani, Mahdi Fathizade

Mohammad Madani

In this paper, a combinatory method of the Laplace transform and the homotopy perturbation method is proposed to solve non-homogeneous partial differential equations with variable coefficients. The obtained approximate solutions are compared with exact solutions and those obtained by other analytical methods, showing reliability of the present method.

Dynamic Failure Properties Of The Porcine Medial Collateral Ligament-Bone Complex For Predicting Injury In Automotive Collisions., Kristen Billiar, Louis Peck, Malcolm Ray

Kristen L. Billiar

The goal of this study was to model the dynamic failure properties of ligaments and their attachment sites to facilitate the development of more realistic dynamic finite element models of the human lower extremities for use in automotive collision simulations. Porcine medial collateral ligaments were chosen as a test model due to their similarities in size and geometry with human ligaments. Each porcine medial collateral ligament-bone complex (n = 12) was held in a custom test fixture placed in a drop tower to apply an axial impulsive impact load, applying strain rates ranging from 0.005 s(-1) to 145 s(-1). The …

Quantitative Assessment Of Sample Stiffness And Sliding Friction From Force Curves In Atomic Force Microscopy, Nancy Burnham, Jon Pratt, Gordon Shaw, Lee Kumanchik

Nancy A. Burnham

It has long been recognized that the angular deflection of an atomic force microscope(AFM) cantilever under “normal” loading conditions can be profoundly influenced by the friction between the tip and the surface. It is shown here that a remarkably quantifiable hysteresis occurs in the slope of loading curves whenever the normal flexural stiffness of the AFM cantilever is greater than that of the sample. This situation arises naturally in cantilever-on-cantilever calibration, but also when trying to measure the stiffness of nanomechanical devices or test structures, or when probing any type of surface or structure that is much more compliant along …

Microstructural Characteristics Of Functionally Graded Materials Designed As Dental Post, Ahmed A. Madfa

Ahmed A. Madfa

To study the interfaces and microstructure of multilayered materials fabricated based on functionally graded concept for use as dental posts.

Cuda Implementation Of A Navier-Stokes Solver On Multi-Gpu Desktop Platforms For Incompressible Flows, Julien C. Thibault, Inanc Senocak

Inanc Senocak

Graphics processor units (GPU) that are traditionally designed for graphics rendering have emerged as massively-parallel "co-processors" to the central processing unit (CPU). Small-footprint desktop supercomputers with hundreds of cores that can deliver teraflops peak performance at the price of conventional workstations have been realized. A computational fluid dynamics (CFD) simulation capability with rapid computational turnaround time has the potential to transform engineering analysis and design optimization procedures. We describe the implementation of a Navier-Stokes solver for incompressible fluid flow using desktop platforms equipped with multi-GPUs. Specifically, NVIDIA’s Compute Unified Device Architecture (CUDA) programming model is used to implement the discretized …

Stochastic Event Reconstruction Of Atmospheric Contaminant Dispersion Using Bayesian Inference, Inanc Senocak, Nicolas W. Hengartner, Margaret B. Short, W. Brent Daniel

Inanc Senocak

Environmental sensors have been deployed in various cities for early detection of contaminant releases into the atmosphere. Event reconstruction and improved dispersion modeling capabilities are needed to estimate the extent of contamination, which is required to implement effective strategies in emergency management. To this end, a stochastic event reconstruction capability that can process information from an environmental sensor network is developed. A probability model is proposed to take into account both zero and non-zero concentration measurements that can be available from a sensor network because of a sensor’s specified limit of detection. The inference is based on the Bayesian paradigm …

New Generation Of The Dental Posts For Endodontic Application., Ahmed A. Madfa

Ahmed A. Madfa

Fabricated multilayer dental post with the functionally graded design is a novel product that exhibits graded properties varied from coronal to apical parts of the tooth. The new dental post definitely performs better than posts available in the market and improves the quality of human life

The Variational Iteration Method Which Should Be Followed, Ji-Huan He, Guo-Cheng Wu, F. Austin

Ji-Huan He

This paper proposes three standard variational iteration algorithms for solving differential equations, integro-differential equations, fractional differential equations, fractal differential equations, differential-difference equations and fractional/fractal differential-difference equations. The physical interpretations of the fractional calculus and the fractal derivative are given and an application to discrete lattice equations is discussed. The paper then examines the acceleration of some iteration formulae with particular emphasis being placed on the exponential Padé approximant that is suggested for solitary solutions and the sinusoidal Padé approximant that is usually used for periodic and compacton solutions. The paper points out that there may not be any physical meaning …

Model Omnibus Privacy Statute, Sam S. Han Ph.D.

Sam Han

One of today’s major concerns is how easily digital information can be copied and disseminated. Thus, when one’s private information becomes publicly available in digital format, that information can be readily duplicated and distributed across the globe within seconds. If the disseminated information includes credit card numbers or Social Security numbers, then there is a heightened exposure to identity theft and a host of other privacy-related crimes.

Given the existence of such a digital landmine, laws have been promulgated for various sectors (e.g., financial, healthcare, government, etc.) to protect personally-identifiable information. However, due to differing needs of the various sectors, …

Lai - Introduction To Continuum Mechanics نسخه اصلی کتاب مکانیک محیط پیوسته ویرایش چهارم, Dr Alireza Zolfaghari

Dr Alireza Zolfaghari

No abstract provided.

Reversible Addition - Fragmentation Chain Transfer In Microemulsions: Effect Of Chain Transfer Agent Aqueous Solubility, Jennifer M. O'Donnell, Eric W. Kaler

Jennifer M. Heinen

Microemulsion polymerizations are attractive for investigating compartmentalization effects in heterogeneous reversible addition - fragmentation chain transfer (RAFT) polymerizations because the propagating radicals are segregated into surfactant stabilized polymer particles, which drastically reduces the effects of biradical termination, Also, microemulsion polymerizations do not involve the large monomer droplets that are present in emulsion and miniemulsion polymerizations. RAFT microemulsion polymerizations of butyl aery late with a high water solubility chain transfer agent, methyl-2-(O-ethylxanthyl)propionate (MOEP), and a low water solubility chain transfer agent, methyl-2-(O-dodecylxanthyl)propionate (MODP), were investigated to determine the effect of chain transfer agent compartmentalization on the control of the polymerization. The …

Optimization And Economic Evaluation Of Industrial Gas Production, Yasar Demirel, A. Kumar, D.D. Jones, M.A. Hanna

YASAR DEMIREL

Thermochemical gasification is one of the most promising technologies for converting biomass into power, fuels and chemicals. The objectives of this study were to maximize the net energy efficiency for biomass gasification, and to estimate the cost of producing industrial gas and combined heat and power (CHP) at a feedrate of 2000 kg/h. Aspen Plus-based model for gasification was combined with a CHP generation model, and optimized using corn stover and dried distillers grains with solubles (DDGS) as the biomass feedstocks. The cold gas efficiencies for gas production were 57% and 52%, respectively, for corn stover and DDGS. The selling …