Enhanced fluorescence and time resolved fluorescence properties of p-terphenyl crystal grown by selective self seeded vertical Bridgman technique

The fluorescence and fluorescence decay time of a modified Bridgman grown p-terphenyl single crystals have been studied. The fluorescence spectra of selective self seeded vertical Bridgman technique (SSVBT) grown p-terphenyl single crystals exhibit intense peak at 372 nm and a hump at 388 nm. Fluorescence lifetime measured by Time Correlated Single Photon Counting (TCSPC) method for p-terphenyl crystal showed a very short fluorescence decay time (τ) of 3.3 ns.     

LCK-phosphorylated human killer cell-inhibitory receptors recruit and activate phosphatidylinositol 3-kinase

HLA-specific killer cell inhibitory receptors (KIR) are thought to impede natural killer (NK) and T cell activation programs through recruitment of the SH2 domain-containing tyrosine phosphatases, SHP-1 and SHP-2, to their cytoplasmic tails (CYT). To identify other SH2 domain-containing proteins that bind KIR CYT, we used the recently described yeast two-bait interaction trap and a modified version of this system, both of which permit tyrosine phosphorylation of bait proteins. Using these systems, we show that KIR CYT, once phosphorylated by the src-family tyrosine kinase LCK, additionally bind the p85alpha regulatory subunit of phosphatidylinositol (PI) 3-kinase. Furthermore, we show that in an NK cell line, NK3.3, cross-linking of KIR results in recruitment of p85alpha to KIR and activation of PI 3-kinase lipid kinase activity. One consequence of KIR coupling to PI 3-kinase is downstream activation of the antiapoptotic protein kinase AKT. Therefore, in addition to providing negative signals, KIR may also contribute positive signals for NK and T cell growth and/or survival.     

Growth and Characterization of Organic NLO Crystal:β-Naphthol

Single crystals of β-Naphthol(βN),an organic nonlinear optical(NLO) material was successfully grown by temperature lowering method using chloroform as solvent.The initial compound was purified by repeated recrystallization process.As-grown crystals were characterized by single crystal X-ray diffraction(XRD) studies to ascertain that βN crystal crystallized in the monoclinic system with a noncemtrosymmetric space group.Vibrational frequencies of various functional groups in the crystals were derived from Fourier transform infrared(FTIR) spectroscopy and proton nuclear magnetic resonance(NMR) spectrum.Optical characterization was done using UV-Visible near-infrared(NIR) spectroscopy.The thermal behaviour of the material was studied by thermo gravimetric and differential thermal plots.Scanning electron microscopy(SEM) study was carried out on the surface of the grown crystals to investigate the nature of defects in the crystal surface and the NLO property of the crystal was tested by Nd:YAG laser as a source.     

Ballistic behaviour of gun powder and flash powder for firework chemicals as a function of particle sizes

In this paper, analysis of ballistic behaviour of gun powder and flash powder of firework chemicals with different particle size have been carried out in a closed vessel to find out the maximum pressure when ignited. The experiment was carried out by changing the variables like sample composition, particle size, vessel volume. Works were carried out to synthesis of nanoflash powders and the particle sizes are 139.7 nm for KNO₃, 94.5 nm for Al and 92.36 nm for S. The nanoflash powders are mixed with micron powders in different ratios and crackers are manufactured. The maximum pressure during the combustion of different samples and explosivity of the crackers are analysed. Results show that peak pressure is increased by 21.6% and explosive impulse is increased by 60% when burning of 100% nfp compared to 10% nfp cracker.     

Role of vapor pressure of 1,4-bis(trimethylsilyl)benzene in developing silicon carbide thin film using a plasma-assisted liquid injection chemical vapor deposition process

The temperature dependence equilibrium vapor pressure (p_e)_T data yielded a straight line when ln(p_e) was plotted against the reciprocal temperature in the range of 312.82-367.12 K, leading to a standard enthalpy of sublimation (Δ_subH°) value of 68.2 ± 0.8 kJ mol^− 1 for 1,4-bis(trimethylsilyl)benzene (TMSB). From the depression of the melting point in the DTA-mode, the standard enthalpy of fusion (Δ_fusH°) was found to be 26.9 ± 2.5 kJ mol^− 1. A thin film of silicon carbide was grown on graphite substrate at 573 K using TMSB or bis(trimethylsilyl)acetylene as precursors. The deposited films were characterized by scanning electron microscopy and energy dispersive X-ray analysis for their composition and morphology.     

Automatic Defect Classification in Ultrasonic NDT Using Artificial Intelligence

A methodology is developed to detect defects in NDT of materials using an Artificial Neural Network and signal processing technique. This technique is proposed to improve the sensibility of flaw detection and to classify defects in Ultrasonic testing. Wavelet transform is used to derive a feature vector which contains two-dimensional information on various types of defects. These vectors are then classified using an ANN trained with the back propagation algorithm. The inputs of the ANN are the features extracted from each ultrasonic oscillogram. Four different types of defect are considered namely porosity, lack of fusion, and tungsten inclusion and non defect. The training of the ANN uses supervised learning mechanism and therefore each input has the respective desired output. The available dataset is randomly split into a training subset (to update the weight values) and a validation subset. With the wavelet features and ANN, good classification at the rate of 94% is obtained. According to the results, the algorithms developed and applied to ultrasonic signals are highly reliable and precise for online quality monitoring.     

Corticosteroids for COVID-19 Therapy: Potential Implications on Tuberculosis

On 11 March 2020, the World Health Organization announced the Corona Virus Disease-2019 (COVID-19) as a global pandemic, which originated in China. At the host level, COVID-19, caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), affects the respiratory system, with the clinical symptoms ranging from mild to severe or critical illness that often requires hospitalization and oxygen support. There is no specific therapy for COVID-19, as is the case for any common viral disease except drugs to reduce the viral load and alleviate the inflammatory symptoms. Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis (Mtb), also primarily affects the lungs and has clinical signs similar to pulmonary SARS-CoV-2 infection. Active TB is a leading killer among infectious diseases and adds to the burden of the COVID-19 pandemic worldwide. In immunocompetent individuals, primary Mtb infection can also lead to a non-progressive, asymptomatic latency. However, latent Mtb infection (LTBI) can reactivate symptomatic TB disease upon host immune-suppressing conditions. Importantly, the diagnosis and treatment of TB are hampered and admixed with COVID-19 control measures. The US-Center for Disease Control (US-CDC) recommends using antiviral drugs, Remdesivir or corticosteroid (CST), such as dexamethasone either alone or in-combination with specific recommendations for COVID-19 patients requiring hospitalization or oxygen support. However, CSTs can cause immunosuppression, besides their anti-inflammatory properties. The altered host immunity during COVID-19, combined with CST therapy, poses a significant risk for new secondary infections and/or reactivation of existing quiescent infections, such as LTBI. This review highlights CST therapy recommendations for COVID-19, various types and mechanisms of action of CSTs, the deadly combination of two respiratory infectious diseases COVID-19 and TB. It also discusses the importance of screening for LTBI to prevent TB reactivation during corticosteroid therapy for COVID-19.     

Computational screening of potential non-immunoglobulin scaffolds using overlapped conserved residues (OCR)-based fingerprints

Cystatins and lipocalins have attracted considerable interest for their potential applications in non-immunoglobulin protein scaffold engineering. In the present study, their potential homologs were screened computationally from non-redundant protein sequence database based on the overlapped conserved residues (OCR)-fingerprints, which can detect the protein family with low sequence identity, such as cystatins and lipocalins. Two types of OCR-fingerprints for each family were designed and showed very high detection efficiency (>90%). The protein sequence database was scanned by the fingerprints, which yielded the hypothetical sequences for cystatins and lipocalins. The hypothetical sequences were validated further based on their sequence motifs and structural models, which allowed an identification of the potential homologs of cystatins and lipocalins.     

One Pot Synthesis and Characterization of Cesium Doped SnO2 Nanocrystals via a Hydrothermal Process

The physico-chemical properties of cesium doped SnO2 nanocrystals synthesized by wet chemical method have been investigated. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), inductively coupled plasma (ICP), atomic absorption spectroscopic (AAS) analyses, UV-vis-NIR spectral studies and dielectric studies were carried out for both pure SnO2 and cesium doped SnO2 nano-samples. All samples of SnO2 did not show any metallic cluster, but the sample containing cesium as a dopant displayed significant activity. The products formed were chloride and water representing a competitive advantage from the stand point of environmental protection.