Sinensetin,rutin, 3′-hydroxy-5, 6, 7, 4′-tetramethoxyflavone and rosmarinic acid contents and antioxidative effect of the skin of apple fruit

A GC–MS method was developed for the separation and quantifiation of three flavones: sinensetin (SEN), rutin (RU) and 3′-hydroxy-5, 6, 7, 4′-tetramethoxyflavone (TMF) and rosmarinic acid (RA), a caffeic acid derivative, in the skin of apple fruit collected from different local markets of Bangladesh. The results showed significant variation in the amount of these markers in methanolic extracts of skin samples from different markets of Bangladesh, even though the values were almost identical for most of the cases. A variation in antioxidant activities, ranging from 62.82 to 92.34%, and variations in total phenolics, ranging from 6.69 to 10.20 mg caffeic acid/g dry weight of the methanol extracts, were observed. Antioxidative potency of the methanolic extracts was comparable to that of pure quercetin and the synthetic antioxidant butylated hydroxylanisole (BHA).     

On the Source of Jitter in a Room-Temperature Nanoinjection Photon Detector at 1.55 $mu hbox{m}$

The transient response of a nanoinjection infrared photon detector was studied by exploring the relation between lateral charge transfer and jitter. The jitter of the device was measured to be 15 ps at room temperature. The jitter was almost independent of the pulse power, even after device saturation. Spatial maps for delay and amplitude were acquired. The carrier velocity was extracted from the measurements and compared with that of the simulation model. The jitter due to transit time was calculated to be in agreement with the measured data, which indicated that the jitter is primarily transit time limited.     

Cytocompatibility property evaluation of gas pressure sintered SiAlON-SiC composites with L929 fibroblast cells and Saos-2 osteoblast-like cells

Although the oxide ceramics have widely been investigated for their biocompatibility, non-oxide ceramics, such as SiAlON and SiC are yet to be explored in detail. Lack of understanding of the biocompatibility restricts the use of these ceramics in clinical trials. It is hence, essential to carry out proper and thorough study to assess cell adhesion, cytocompatibility and cell viability on the non-oxide ceramics for the potential applications. In this perspective, the present research work reports the cytocompatibility of gas pressure sintered SiAlON monolith and SiAlON-SiC composites with varying amount of SiC, using connective tissue cells (L929) and bone cells (Saos-2). The quantification of cell viability using MTT assay reveals the non-cytotoxic response. The cell viability has been found to be cell type dependent. An attempt has been made to discuss the cytocompatibility of the developed composites in the light of SiC content and type of sinter additives.     

Trend and efficiency analysis of co-authorship network

Although co-authorship in scientific research has a long history the analysis of co-authorship network to explore scientific collaboration among authors is a relatively new research area. Studies of current literature about co-authorship networks mostly give emphasis to understand patterns of scientific collaborations, to capture collaborative statistics, and to propose valid and reliable measures for identifying prominent author(s). However, there is no such study in the literature which conducts a longitudinal analysis of co-authorship networks. Using a dataset that spans over 20 years, this paper attempts to explore efficiency and trend of co-authorship networks. Two scientists are considered connected if they have co-authored a paper, and these types of connections between two scientists eventually constitute co-authorship networks. Co-authorship networks evolve among researchers over time in specific research domains as well as in interdisciplinary research areas. Scientists from diverse research areas and different geographical locations may participate in one specific co-authorship network whereas an individual scientist may belong to different co-authorship networks. In this paper, we study a longitudinal co-authorship network of a specific scientific research area. By applying approaches to analyze longitudinal network data, in addition to known methods and measures of current co-authorship literature, we explore a co-authorship network of a relatively young and emerging research discipline to understand its trend of evolution pattern and proximity of efficiency.     

Optimization of localized surface plasmon resonance transducers for studying carbohydrate-protein interactions

Noble metal nanostructures supporting localized surface plasmons (SPs) have been widely applied to chemical and biological sensing. Changes in the refractive index near the nanostructures affect the SP extinction band, making localized surface plasmon resonance (LSPR) spectroscopy a convenient tool for studying biological interactions. Carbohydrate-protein interactions are of major importance in living organisms; their study is crucial for understanding of basic biological processes and for the construction of biosensors for diagnostics and drug development. Here LSPR transducers based on gold island films prepared by evaporation on glass and annealing were optimized for monitoring the specific interaction between Concanavalin A (Con A) and D-(+)-mannose. The sugar was modified with a PEG-thiol linker and immobilized on the Au islands. Sensing assays were performed under stationary and flow conditions, the latter providing kinetic parameters for protein binding and dissociation. Ellipsometry and Fourier transform-infrared (FT-IR) data, as well as scanning electron microscopy (SEM) imaging of fixated and stained samples, furnished independent evidence for the protein-sugar recognition. Enhanced response and visual detection of protein binding was demonstrated using Au nanoparticles stabilized with the linker-modified mannose molecules. Mannose-coated transducers display an excellent selectivity toward Con A in the presence of a large excess of bovine serum albumin (BSA).     

Design and performance of a 4He-evaporator at <1.0 K

A helium evaporator for obtaining 1 K temperature has been built and tested in laboratory. This will function primarily as the precooling stage for the circulating helium isotopic gas mixture. This works on evaporative cooling by way of pumping out the vapour from the top of the pot. A precision needle valve is used initially to fill up the pot and subsequently a permanent flow impedance maintains the helium flow from the bath into the pot to replenish the evaporative loss of helium. Considering the cooling power of 10 mW @1.0 K, a 99.0 cm³ helium evaporator was designed, fabricated from OFE copper and tested in the laboratory. A pumping station comprising of a roots pump backed by a dry pump was used for evacuation. The calibrated RuO thermometer and kapton film heater were used for measuring the temperature and cooling power of the system respectively. The continuously filled 1 K bath is tested in the laboratory and found to offer a temperature less than 1.0 K by withdrawing vapour from the evaporator. In order to minimize the heat load and to prevent film creep across the pumping tube, size optimization of the pumping line and pump-out port has been performed. The results of test run along with relevant analysis, mechanical fabrication of flow impedance are presented here.     

Effect of vehicle systems, pH and enhancers on the permeation of highly lipophilic aripiprazole from Carbopol 971P gel systems across human cadaver skin

The objective of this study was to investigate the effect of vehicle systems, pH and enhancers on the permeation of a highly lipophilic basic drug aripiprazole (ARPZ) through human cadaver skin. Solubility of ARPZ in single, binary, tertiary, and quaternary vehicle systems of N-methyl pyrrolidone (NMP), dimethyl sulfoxide (DMSO), water, ethanol and isopropyl myristate (IPM) was studied. Gel formulations of 5% ARPZ were developed with 0.5% Carbopol 971P in quaternary vehicle systems consisting of NMP, DMSO, water and ethanol or IPM at optimum ratio of 40/40/5/15. The effect of pH of the gel formulations and fatty acids with different chain lengths on the permeation was studied. The flux of ARPZ from gel formulation with IPM and ethanol was comparable. A four fold increase in APRZ flux was observed when the pH of the gel systems was lowered from pH 8.2 to pH 6 or pH 7. For fatty acids, the order of flux is lauric acid > myristic acid > caprylic acid > oleic acid. In all the cases, in vitro permeation rate of ARPZ through human cadaver skin followed zero order kinetics. This study demonstrated that ARPZ in tertiary vehicle system of NMP/DMSO/water/IPM at ratio of 40/40/5/15 and gel system of Carbopol 971P with pH 7 is a promising candidate for transdermal delivery.     

Indoor air pollution from particulate matter emissions in different households in rural areas of Bangladesh

Indoor air pollution from the combustion of traditional biomass fuels (wood, cow dung, and crop wastes) is a significant public health problem predominantly for poor populations in many developing countries. It is particularly problematic for the women who are normally responsible for food preparation and cooking, and for infants/young children who spend time around their mothers near the cooking area. Airborne particulate matter (PM) samples were collected from cooking and living areas in homes in a rural area of Bangladesh to investigate the impact of fuel use, kitchen configurations, and ventilation on indoor air quality and to apportion the source contributions of the measured trace metals and BC concentrations. Lower PM concentrations were observed when liquefied petroleum gas (LPG) was used for cooking. PM concentrations varied significantly depending on the position of kitchen, fuel use and ventilation rates. From reconstructed mass (RCM) calculations, it was found that the major constituent of the PM was carbonaceous matter. Soil and smoke were identified as components from elemental composition data. It was also found that some kitchen configurations have lower PM concentrations than others even with the use of low-grade biomass fuels. Adoption of these kitchen configurations would be a cost-effective approach in reducing exposures from cooking in these rural areas.