Synthesis and studies of the zinc acetate (ZA) crystal for dielectric,nano-photonics and electronic applications

Journal of Materials Science: Materials in Electronics - The ZA are finely full-grown by usual slow evaporation solution growing scheme and the single XRD shows the crystal size as well as the...     

Study on antioxidant activity of certain plants in Thailand: Mechanism of antioxidant action of guava leaf extract

The ethanol extracts from 24 samples plant species commonly found in Thailand were investigated and compared on their antioxidant activity by ABTS assay. The ethanol extract from the leaves of guava (Psidium guajava) showed the highest antioxidant capacity with the TEAC value of 4.908 ± 0.050 mM/mg, followed by the fruit peels of rambutan (Nephelium lappaceum) and mangosteen (Garcinia mangostana) with the TEAC values of 3.074 ± 0.003 and 3.001 ± 0.016 mM/mg, respectively. The further investigation of guava leaf extracts from different solvents; n-hexane, ethyl acetate, n-butanol, and methanol, was examined using ABTS and FRAP assays. The total phenolic content was done by Folin–Ciocalteu reaction. The results indicated that the methanol fraction possessed the highest antioxidant activity, followed by the butanol and ethyl acetate fractions, respectively. The hexane fraction showed the lowest antioxidant activity. The results demonstrated that the mechanism of antioxidant action of guava leaf extracts was free radical scavenging and reducing of oxidized intermediates. The phenolic content in guava leaf fraction played a significant role on the antioxidant activity via reducing mechanisms.     

Morphological and physiological responses of Campylobacter jejuni to stress

Under conditions of stress, cells of Campylobacter assume a coccoid shape that may be an evolutionary strategy evolved by the organism to enable survival between hosts. However, the physiology of Campylobacter as it devolves from spiral to coccoid-shaped morphology is poorly understood. In this study, conditions influencing the survival of Campylobacter jejuni ATCC 35921 in broth were determined. Cells in late log phase were resuspended in broth at 4 or 60 degrees C. The culturability of these cold- or heat-stressed cell suspensions was determined by spread plate counts and the activity of cells by the direct viable count technique and 5-cyano-2,3-ditolyltetrazolium chloride staining. C. jejuni changed form completely from culturable to viable but nonculturable cells (VBNC) within 25 days at 4 degrees C, and 15 min at 60 degrees C. Light microscopy of C. jejuni VBNC cells showed that the spiral-shaped cells became coccoid, and transmission electron microscopy of C. jejuni VBNC cells showed that the outer membrane was lost in aging cell suspensions. Furthermore, a limited proteomic study was carried out to compare C. jejuni proteins that exhibited increased or decreased synthesis on exposure to 60 degrees C.     

In vitro biological evaluation of anti‐diabetic activity of organic–inorganic hybrid gold nanoparticles

Diabetes mellitus has been considered as a heterogeneous metabolic disorder characterised by complete or relative impairment in the production of insulin by pancreatic β‐cells or insulin resistance. In the present study, propanoic acid, an active biocomponent isolated from Cassia auriculata is employed for the synthesis of propanoic acid functionalised gold nanoparticles (Pa@AuNPs) and its anti‐diabetic activity has been demonstrated in vitro. In vitro cytotoxicity of synthesised Pa@AuNPs was performed in L6 myotubes. The mode of action of Pa@AuNPs exhibiting anti‐diabetic potential was validated by glucose uptake assay in the presence of Genistein (insulin receptor tyrosine kinase inhibitor) and Wortmannin (Phosphatidyl inositide kinase inhibitor). Pa@AuNPs exhibited significant glucose uptake in L6 myotubes with maximum uptake at 50 ng/ml. Assays were performed to study the potential of Pa@AuNPs in the inhibition of protein‐tyrosine phosphatase 1B, α‐glucosidases, and α‐amylase activity.Inspec keywords: molecular biophysics, biomedical materials, sugar, enzymes, nanofabrication, gold, patient treatment, organic‐inorganic hybrid materials, biochemistry, diseases, cellular biophysics, nanoparticles, toxicology, nanomedicineOther keywords: glucose uptake assay, α‐amylase activity, organic–inorganic hybrid gold nanoparticles, diabetes mellitus, heterogeneous metabolic disorder, pancreatic β‐cells, insulin resistance, propanoic acid, antidiabetic potential, antidiabetic activity, in vitro cytotoxicity, L6 myotubes, Genistein, IRTK inhibitor, Wortmannin, P13K inhibitor, protein‐tyrosine phosphatase 1B, α‐glucosidases, Cassia auriculata, Au     

Rice-net: an efficient artificial fish swarm optimization applied deep convolutional neural network model for identifying the Oryza sativa diseases

Neural Computing and Applications - This research aims to identify rice diseases, namely Leaf blast, Brown spot, Healthy and Hispa. The purpose of this research is to utilize deep convolutional...     

A study on various methods used for video summarization and moving object detection for video surveillance applications

With the advancement in digital video technology, video surveillance has been playing its vital role for ensuring safety and security. The surveillance systems are deployed in wide range of applications to invigilate stuffs and to analyse the activities in the environment. From the single or multi surveillance camera, a huge amount of data is generated, stored and processed for security purpose. Due to time constraints, it is a very tedious process for an analyst to go through the full content. This limitation has been overcome by the use of video summarization. The video summarization is intended to afford comprehensible analysis of video by removing duplications and extracting key frames from the video. To make an easily interpreted outline, the various available video summarization methods will try to shot the summary of the main occurrences, scenes, or objects in a frame. Depending on the applications, it is required to summarize the happenings in the scene and detect the objects (static/dynamic) which is recorded in the video. Hence this paper provides the various methods used for video summarization and a comparative study of different techniques. It also presents different object detection, object classification and object tracking algorithms available in the literature.     

Nonparametric dynamically weighted combination model to determine when to stop testing

Software manufacturers need to minimize the number of their software failures in their production environments. So, software reliability becomes a critical factor for these manufacturers to focus on. Software Reliability Growth Models (SRGMs) are used as indicators of the number of failures that may be faced after the shipping of the software and thus are indicators of the readiness of the software for shipping. SRGMs to handle varying operational profiles have been proposed by researchers earlier. However, as it is difficult to predict the nature of the project in advance, the reliability engineer has to try out each model one at a time before zeroing in on the model to be used in the project. We have derived a combination model, called dynamically weighted infinite NHPP combination, using the existing models for determining the release time. The nonparametric dynamically weighted combination model that we propose was validated and was found to be effective.

     

Approximate controllability of fractional stochastic evolution equations

A class of dynamic control systems described by nonlinear fractional stochastic differential equations in Hilbert spaces is considered. Using fixed point technique, fractional calculations, stochastic analysis technique and methods adopted directly from deterministic control problems, a new set of sufficient conditions for approximate controllability of fractional stochastic differential equations is formulated and proved. In particular, we discuss the approximate controllability of nonlinear fractional stochastic control system under the assumptions that the corresponding linear system is approximately controllable. The results in this paper are generalization and continuation of the recent results on this issue. An example is provided to show the application of our result. Finally as a remark, the compactness of semigroup is not assumed and subsequently the conditions are obtained for exact controllability result.     

Investigations on the corrosion behaviour and biocompatibility of magnesium alloy surface composites AZ91D-ZrO2 fabricated by friction stir processing

In the current study, friction stir processing was applied as a methodology to produce surface composites of AZ91D magnesium alloy with ZrO₂ particles. Microstructural evolution, microhardness profile and corrosion behaviour of the developed surface composite were analysed. The results indicate that the combined effect of friction stir processing and reinforcement of ZrO₂ reduced the grain size, and fragmented and dispersed the secondary phases. The fine dispersion of ZrO₂ particles contributed to the enhancement of cumulative surface potential, and hence the corrosion resistance of the developed surface composite. The analysis of post-corrosion test specimens revealed the formation of corrosion products that had similar composition to that of hydroxyapatite. The formation of such corrosion products is beneficial, as it contributes to corrosion resistance (stable and adherent layer) and biocompatibility.