Vinaya Kelkar

Natural killer T cell facilitated engraftment of rat skin but not islet xenografts in mice

Abstract:  Background:  We have studied cellular components required for xenograft survival mediated by anti‐CD154 monoclonal antibody (mAb) and a transfusion of donor spleen cells and found that the elimination of CD4+ but not CD8+ cells significantly improves graft survival. A contribution of other cellular components, such as natural killer (NK) cells and natural killer T (NKT) cells, for costimulation blockade‐induced xenograft survival has not been clearly defined. We therefore tested the hypothesis that NK or NKT cells would promote rat islet and skin xenograft acceptance in mice.

An Initiative to Broaden Diversity in Undergraduate Biomathematics Training

At North Carolina A&T State University (NCATSU), there was a critical need to better coordinate genuine research and classroom experiences for undergraduates early in their academic career. We describe the development and implementation of a faculty alliance across academic departments to increase biomathematics research opportunities for underrepresented minorities. Our faculty alliance is called the Integrative Biomathematical Learning and Empowerment Network for Diversity (iBLEND). The fundamental purpose of the iBLEND alliance was to inspire underrepresented minorities to pursue research careers by increasing the visibility of research conducted at the interface of mathematics and biology at NCATSU. Because of the many positive impacts, iBLEND gained significant buy-in from administration, faculty, and students by 1) working from the ground up with administration to promote campus-wide biomathematics research and training, 2) fostering associations between research and regular undergraduate academic courses, 3) creating and disseminating biomathematics teaching and learning modules, and 4) enhancing learning community support at the interface of mathematics and biology. Currently, iBLEND is viewed as a productive site for graduate schools to recruit underrepresented minority students having specific competencies related to mathematical biology.

Preliminary Report: A case study: the identification and taste preference for regular versus reduced-fat containing food in African-American young adults

Abstract. About 70% of African-Americans are currently overweight. Among these overweight individuals, 40% are adults aged 20 years and older. Such high incidence of overweight cases in African-Americans raises the question: does this population have a taste preference for dietary fat? The objective of this study was to determine if dietary fat preference depends on taste sensitivity in young African-American adults. Fifty-seven African-Americans aged 18 to 21 voluntarily participated in the study. Two types of commonly consumed food, lasagna and macaroni and cheese, were used. Each food type had two versions prepared with identical ingredients and cooking methods, except for total fat content (reduced-fat versus regular-fat). Demographic data, food consumption frequency, correct identification, and taste preference were collected and analyzed using the Student t-test, Chi-Square, and Pearson correlation tests at the 5% significance level. Results revealed a significant correlation between dietary preference and ability to identify fattier food samples (p < 0.05). The majority of participants (79%) that correctly identified reduced-fat or regular-fat containing food types preferred the regular-fat-containing version (p < 0.05). Gender, but not BMI, was significantly related to identification of different fat-containing food products. The finding provides valuable information about food preferences and eating habits of African-American young adults, and such information could be useful for nutrition education or dietary intervention in the future.

Prediction of Mechanical Properties of EPON 862 (DGEBF) cross-linked with Curing Agent W (DETDA) and SWCNT using MD Simulations

The present study focuses on the prediction of mechanical properties of single-walled carbon nanotubes (SWCNT) reinforced epoxy resin (DGEBF) cross-linked with curing agent W (DETDA). The MD models of the reinforced epoxy were built using the amorphous module of Material Studio (Accelrys Inc.). The COMPASS force field was used in the simulations. The amorphous structure was achieved by using periodic boundary conditions and then subjecting to an energy minimization using an ensemble of the constant-volume and temperature (NVT). The structures were equilibrated for 100 picoseconds (ps) and then followed by MD equilibrations at room temperature for another 200 ps. Since at room temperature most of the atoms are in static mode, the atoms were excited using simulation temperatures above the glass transition temperatures. In an attempt of finding global energy minimum, simulated annealing runs were then carried out starting at elevated temperatures at atmospheric pressure using the ensembles of the constant number of particles, constant-pressure and constant temperature (NPT). The molecular structure temperature was then gradually lowered to a room temperature. Each subsequent simulation was started from the final configuration obtained at the preceding temperature. Density of the epoxy at each temperature was calculated from the average specific volume and glass transition temperature (Tg) was estimated based on the discontinuity in the slope of the density-temperature plot. The amorphous structures obtained at room temperature were analyzed to determine the fundamental mechanical properties of the SWCNT reinforced EPON 862-W. Calculations of fundamental mechanical material properties of single-walled carbon nanotube (CNT) were performed using molecular dynamics simulations via Material Studio. A simple but effective technique of extrapolation was adopted to compensate for the problem of CNT distortion because of smaller lattice sizes. Property calculations were performed at each density value and extrapolated to the actual value of density equal to 1.9 gm/cm 3 . A similar extrapolation technique was employed to overcome the issue of achieving exact theoretical

Prediction of Mechanical Properties of EPON 862 (DGEBF)- W (DETDA) using MD Simulations

The present study). A quad oligomer of DEGBF cross-linked with DETDA was used for the calculations. A MD model of the epoxy was built using the amorphous module of Material Studio (Accelrys Inc.). The Polymer Consistent Force Field (PCFF) was used in the simulation. The amorphous structure was achieved by giving periodic boundary conditions and then subjected to an energy minimization using the ensemble of the constant-volume and temperature (NVT). The structure was equilibrated for 100 picoseconds (ps) followed by a MD equilibration at room temperature for another 200 ps. Since at room temperature most of the atoms are in static mode, the atoms were excited using simulation temperatures above the glass transition temperatures. In an attempt of finding the global energy minimum, simulated annealing runs were carried out starting at elevated temperatures and atmospheric pressure using the ensembles of the constant number of particles, constant-pressure and constant temperature (NPT). The temperature was gradually lowered to room temperature level. Each subsequent simulation was started from the final configuration obtained at the preceding temperature. Density of the epoxy at each temperature was calculated from the average specific volume and glass transition temperature (Tg) was estimated based on the discontinuity in the slope of the density-temperature plot. The amorphous structure obtained at room temperature was analyzed to determine the fundamental mechanical properties of EPON 862-W.

Minimizing scatter in load-controlled fatigue test data of textile polymer matrix composites using statistical techniques

Abstract Polymer matrix composites are composed of fiber reinforcement and polymer matrix. Fiber reinforcement is major load carrying component whereas matrix transfers load between the fibers. Fiber reinforcement in the form of textile fabric is popular in the composite industry. Fibers in textile form exhibit good out of plane properties, and good fatigue and impact resistance. The variety of fabric architectures includes weaves, knits, braids, and stitched fabric. Mechanical properties of the composites are dependent on fiber volume percentage and fiber orientation angle. Composites manufactured using low-cost vacuum infusion processes typically have varying fiber volume percentage from location to location and there exists some degree of fiber misalignment. In load controlled fatigue test, fatigue stress is applied as percentage of average ultimate tensile strength (UTS). Due to variation in fiber volume percentage and misalignment in fibers the UTS varies from specimen to specimen. The variation in the UTS between the specimens causes relatively large scatter in the fatigue data. The scatter can be confirmed on stress-cycle (S / Su  − N) diagram. Stress-cycle diagram is major tool in predicting fatigue life of the composites. The large scatter in this diagram causes erroneous predictions. The large scatter is because of the considerable difference between average UTS and specimen’s actual UTS. It is necessary to apply fatigue stress based on specimen’s actual UTS. Since, evaluation of UTS is a destructive test there is need to predict UTS of specimen using some analytical tool. In this research braided fabric which is one of the forms of textile fabrics, was used in vacuum assisted resin transfer molding (VARTM) to produce flat composite panels. It was observed that the UTS is a function of the braid angle and fiber volume percentage. Using statistical approach an equation is derived for UTS as function of braid angle and fiber volume percentage. It is suggested that braid angle and fiber volume percentage be measured on each specimen. Then compute UTS of that specimen using derived equation. Then apply fatigue stress based on this computed UTS. This approach would minimize scatter in fatigue data. This approach can be used for any type of composites where UTS is dependent on multiple factors such as fabric orientation angle and fiber volume percentage.