Genotypic characterization of Listeria spp. isolated from fresh water fish

A total of 200 samples (muscles and viscera, 100 of each) of fresh water fish, walking catfish (Clarias batrachus) were screened for Listeria spp. All the samples were subjected to a two-step enrichment followed by plating on selective media. Confirmation of the isolates was on the basis of biochemical characters, haemolysis on blood agar and Christie, Atkins, Munch Petersen test. A total of 39 isolates of Listeria spp. were recovered. Of these 26 (67%), 8 (21%), 3 (8%) and 2 (5%) were Listeria monocytogenes, Listeria seeligeri, Listeria grayi and Listeria welshimeri, respectively. The isolates were subjected to a PCR assay for detection of the virulence-associated genes individually or together. The plcA, actA, hlyA and iap genes were detected in six strains, three genes (actA, hlyA and iap) in nine strains, the plcA, hlyA and iap in our strain, the hlyA and iap were in three strains, actA and hlyA in four strains, plcA and hlyA in our strain and hlyA in two strains. The hlyA and iap were also detected in L. seeligeri.     

Designing a support for borohydride through grafting onto crosslinked polyvinylpyrrolidone

Crosslinked polyvinylpyrrolidone (PVPy) was grafted with polyvinylpyridine by irradiating the polymer beads in air from a Co⁶⁰ γ-radiation source and then heating with 4-vinylpyridine (4-VP) in water. The percentage of grafting was studied as a function of various reaction parameters and was determined from the increase in weight of PVPy and from the estimation of pyridine rings introduced into the polymer. PVPy-g-poly(4-VP) was treated with sodium in ethanol, which is known to reduce pyridine into piperidine together with small amounts of 1,2,5,6-tetrahydropyridine. On methylation with dimethyl sulfate and alkali, these are further converted into N,N-dimethylpiperidinium groups. The dimethylpiperidinium graft was used to support borohydride ions and the graft copolymer was shown to cleanly reduce several carbonyl compounds to the corresponding alcohols. © 1996 John Wiley & Sons, Inc.     

Efficient mapping and acceleration of AES on custom multi‐core architectures

Multi‐core processors can deliver significant performance benefits for multi‐threaded software by adding processing power with minimal latency, given the proximity of the processors. Cryptographic applications are inherently complex and involve large computations. Most cryptographic operations can be translated into logical operations, shift operations, and table look‐ups. In this paper we design a novel processor (called mu‐core) with a reconfigurable Arithmetic Logic Unit, and design custom two‐dimensional multi‐core architectures on top of it to accelerate cryptographic kernels. We propose an efficient mapping of instructions from the multi‐core grid to the individual processor cores and illustrate the performance of AES‐128E algorithm over custom‐sized grids. The model was developed using Simulink and the performance analysis suggests a positive trend towards development of large multi‐core (or multi‐ µ‐core) architectures to achieve high throughputs in cryptographic operations. Copyright © 2010 John Wiley & Sons, Ltd.     

Automated analysis of fluorescence lifetime imaging microscopy (FLIM) data based on the Laguerre deconvolution method

In fluorescence lifetime imaging microscopy (FLIM), fluorescence time decay at each pixel of the imaged sample are measured. Every recorded fluorescence decay corresponds to the time convolution of the instrument response with the intrinsic fluorescence impulse response function (IRF), from which the sample fluorescence lifetime is determined. To estimate the IRF, the instrument response thus needs to be deconvolved from the recorded fluorescence decay. We have recently introduced a novel FLIM time-deconvolution method based on the linear expansion of the fluorescence decays on an orthonormal Laguerre basis. Since this method allows simultaneous estimation of the IRFs at all pixels, it performs at least two orders of magnitude faster than standard algorithms. In its original implementation, however, the Laguerre basis, determined by the Laguerre parameter α, is selected using a heuristic approach. Here, we present an automated implementation, whereby the Laguerre parameter α is treated as a free parameter within a nonlinear least squares optimization scheme. The new implementation combines the unmatched inherent computational speed of the Laguerre deconvolution method with a systematic model selection approach. This method will thus facilitate applications of FLIM requiring automatic estimation of the spatial distribution of fluorescence lifetimes, such as in in vivo tissue FLIM imaging.     

A novel approach for analyzing severe crash patterns on multilane highways

This study presents a novel approach for analysis of patterns in severe crashes that occur on mid-block segments of multilane highways with partially limited access. A within stratum matched crash vs. non-crash classification approach is adopted towards that end. Under this approach crashes serve as units of analysis and it does not require aggregation of crash data over arterial segments of arbitrary lengths. Also, the proposed approach does not use information on non-severe crashes and hence is not affected by under-reporting of the minor crashes. Random samples of time, day of week, and location (i.e., milepost) combinations were collected for multilane arterials in the state of Florida and matched with severe crashes from the corresponding corridor to form matched strata consisting of severe crash and non-crash cases. For these cases, geometric design/roadside and traffic characteristics were derived based on the corresponding milepost locations. Four groups of crashes, severe rear-end, lane-change related, pedestrian, and single-vehicle/off-road crashes, on multilane arterials segments were compared separately to the non-crash cases. Severe lane-change related crashes may primarily be attributed to exposure while single-vehicle crashes and pedestrian crashes have no significant relationship with the ADT (Average Daily Traffic). For severe rear-end crashes speed limit, ADT, K-factor, time of day/day of week, median type, pavement condition, and presence of horizontal curvature were significant factors. The proposed approach uses general roadway characteristics as independent variables rather than event-specific information (i.e., crash characteristics such as driver/vehicle details); it has the potential to fit within a safety evaluation framework for arterial segments.     

Fabrication and characterization of zinc oxide piezoelectric MEMS resonator

Microsystem Technologies - Micro electromechanical system resonators (MEMS) are being explored to fulfil the demands of speedy wireless communication circuits, which may be utilized as oscillators...     

Simple method for the simultaneous evaluation of combustion and selective oxidation catalysts

The conventional rapid combustion technique used for microanalysis of organic compounds has been modified for the simultaneous evaluation of combustion and selective oxidation catalysts. Using this technique, MnO₂ has been confirmed to be a good combustion catalyst. It was also possible to conclude that Fe₂O₃ and V₂O₅ are good selective oxidation catalysts at 250°C and 300°C, respectively. This simple and rapid method offers much scope for probing into the mechanism of oxidation of hydrocarbons.     

Immunochemical studies in multiple myeloma

Many hospitals are converting to electronic records and allied health professionals are required to modify their traditional documentation practices to accommodate this new technology. This paper discusses a study conducted to determine the computer anxiety and attitudes of physical, occupational, and speech therapists in a large urban teaching hospital before and after the implementation of a computerized documentation system. Fifty-three therapists surveyed with a preinstallation questionnaire reported mild computer anxiety and generally good attitudes about the planned computer system. A greater amount of previous computer use and better self-related computer skills were consistent with less computer anxiety. Seven of the original sample became the first to use the computer system. After their six month trial period, surveys revealed a reduction in computer anxieties. Manual time logs completed before and after the system implementation revealed a significant decrease in total documentation time when using computers.     

Passivation of GaAs FET's with PECVD silicon nitride films ofdifferent stress states

The passivation of GaAs MESFETs with plasma-enhanced chemical-vapor-deposited (PECVD) silicon nitride films of both compressive and tensile stress is reported. Elastic stresses included in GaAs following nitride passivation can produce piezoelectric charge density, which results in a shift of MESFET characteristics. The shift of MESFET parameters due to passivation was found to be dependent on gate orientation. The experiments show that nitride of tensile stress is preferable for MESFETS with [011-bar] oriented gates. The shifts in V_TH,I_DSS, and G_M of the devices before and after nitride passivation are less than 5% if the nitride of appropriate stress states are used for passivation. The breakdown voltage of the MESFETs after nitride deposition was also studied. It is found that the process with higher hydrogen incorporation tends to reduce the surface oxide and increase the breakdown voltage after nitride deposition. In addition, the passivation of double-channel HEMTs is reported for the first time     

Texture Characterization of High-Temperature Superconductor Wires

Texture measurements have been made for BSCCO tapes produced by dip coating and by powder-in-tube techniques. The texture of the Bi2212 grains was characterized for both c axis texture using (001) pole figures from 008 reflections and a–b axis texture using (115) pole figures. The critical current densities of these tapes were also measured and correlated with texture parameters obtained from contours of the pole figures. For the tapes with good current transport, the arrangement of grains in a crystallographic sense was inferred from the pole figures and was found to be consistent with a model based on global alignment of the c axes and the presence of colonies of grains differing mostly in c axis twist.