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Structural and Electrochemical Characterization of Nanostructured Titanium Thin Films Prepared by DC Magnetron Sputtering with Supported Discharge
No full textIn this study, nanostructured titanium (Ti) thin films were prepared by direct current magnetron sputtering (diode mode) and supported discharge (triode mode) on a stainless steel substrate. The X-ray diffraction pattern shows a preferred orientation (002) plane and exhibits a hexagonal cubic structure for the film prepared at a lower working pressure (0.7 Pa). The electrical resistivity was found to be 15 mu ohm-cm. The scanning electron microscopy analysis indicates that the coatings in triode mode have agglomerates with larger grains compared to the DC magnetron sputtering diode mode. The surface topography was examined by atomic force microscopy. The electrochemical studies of the Ti thin films coated at a lower working pressure (0.7 Pa) provide evidence for better corrosion resistance
Synthesis and Electrochemical Performances of gamma-KCoPO4 Nanocrystals as Promising Electrode for Aqueous Supercapatteries
No full textHerein, discrete gamma-KCoPO4 nanocrystals were prepared by a facile, green and fast sol-gel route. The lattice parameters as well as positional and displacement parameters of atoms in the average gamma-KCoPO4 structure with a space group of P2(1)/n were calculated using full profile Rietveld refinement. Monodispersed quadrangular gamma-KCoPO4 nanocrystals with improved phase purity and crystallinity were found through XRD patterns and HRTEM images. Subsequently, the prepared gamma-KCoPO4 nanocrystals were tested as electrode material for supercapatteries in aqueous electrolytes. The gamma-KCoPO4 electrode shows superior specific charge capacity of 309 C g(-1) at 1 mV s(-1) in 1 M KOH, compared to 1 M NaOH (222 C g(-1)) and 1 M LiOH (77 C g(-1)). Further, it exhibits improved electrochemical activity by delivering an impressive specific charge capacity of 100 C g(-1) at a current of 0.6 mA cm(-2) in an aqueous electrolyte medium with acceptable capacity retention. A lab-scale supercapattery was assembled resembling the commercial device. The fabricated device delivered an enhanced specific energy of 28 W h kg(-1) and a specific power of 1600 W kg(-1) and prolonged cycle life of about 5000 cycles
Post-spreading behavior of impacting fuel drops on stainless steel surface
No full textHydrocarbon fuel drops impacting on metallic solid surfaces kept at room temperature exhibit no receding after the completion of early inertia-driven primary spreading. The experimental data of impacting drops of different fuels on a smooth stainless steel surface reveal a sluggish spreading, referred to as post-spreading, after reaching the maximum spreading diameter at the end of primary spreading. A systematic analysis involving maximum spreading factor, final spreading factor and temporal variation of post-spreading diameter of impacting fuel drops of varying Weber number is reported to describe the behavior of the post-spreading process. It is found that the dynamics of post-spreading of impacting fuel drops is different from Tanner's spreading as the exponent n in the power law describing the temporal spreading behavior (beta proportional to tau(n)) varies with Weber number and is significantly less than 0.1. The extent of post-spreading is found to be as high as 20% of the maximum spread factor for the impact of low Weber number fuel drops. Due to the presence of post-spreading, the final spread factor of impacting fuel drops is always higher than the maximum spread factor
Enhancement of the Nuclear Spin Noise Signal Using Wavelet Transform
No full textSpin noise spectroscopy has attracted considerable attention recently owing partly to intrinsic interest in the phenomenon and partly to its significant application potential. Here, we address the inherent problem of low sensitivity of nuclear spin noise and examine the utility of wavelet transform to mitigate this problem by distinguishing real peaks from the noise contaminated data. Suppression of the random circuit noise and the consequent enhancement of the correlated nuclear spin noise signal have been demonstrated with discrete wavelet transform. Spectra of both H-1 and C-13 nuclear spins have been considered and significant signal enhancements in both the cases have been observed. A detailed analysis of several possible wavelet, thresholding and decomposition solutions have been made to obtain the optimum condition for signal enhancement. It is observed that the application of wavelet transform leaves the spin noise signal line shape essentially unchanged, which is an advantage for several applications involving spin noise spectra
Linking Termite Feeding Preferences and Soil Physical Functioning in Southern-Indian Woodlands
No full textTermites are undoubtedly amongst the most important soil macroinvertebrate decomposers in semi-arid environments in India. However, in this specific type of environment, the influence of termite foraging activity on soil functioning remains unexplored. Therefore, this study examines the link between the quality of litter and the functional impact of termite feeding preferences on soil properties and soil hydraulic conductivity in a deciduous forest in southern India. Different organic resources (elephant dung: ``ED'', elephant grass: ``EG'', acacia leaves: ``AL'' and layers of cardboard: ``CB'') were applied on repacked soil cores. ED appeared to be the most attractive resource to Odontotermes obesus, leading to a larger amount of soil sheeting (i.e., the soil used by termites for covering the litter they consume), more numerous and larger holes in the ground and a lower soil bulk density. As a consequence, ED increased the soil hydraulic conductivity (4-fold) compared with the control soil. Thus, this study highlights that the more O. obesus prefers a substrate, the more this species impacts soil dynamics and water infiltration in the soil. This study also shows that ED can be used as an efficient substrate for accelerating the infiltration of water in southern-Indian soils, mainly through the production of galleries that are open on the soil surface, offering new perspectives on termite management in this environment
Evidence for Highly Variable, Region-Specific Patterns of T-Cell Epitope Mutations Accumulating in Mycobacterium tuberculosis Strains
No full textVaccines that confer protection through induction of adaptive T-cell immunity rely on understanding T-cell epitope (TCE) evolution induced by immune escape. This is poorly understood in tuberculosis (TB), an ancient, chronic disease, where CD4 T-cell immunity is of recognized importance. We probed 905 functionally validated, curated human CD4 T cell epitopes in 79 Mycobacterium tuberculosis (Mtb) whole genomes from India. This screen resulted in identifying 64 mutated epitopes in these strains initially using a computational pipeline and subsequently verified by single nucleotide polymorphism (SNP) analysis. SNP based phylogeny revealed the 79 Mtb strains to cluster to East African Indian (EAI), Central Asian Strain (CAS), and Beijing (BEI) lineages. Eighty-nine percent of the mutated T-cell epitopes (mTCEs) identified in the 79 Mtb strains from India has not previously been reported. These mTCEs were encoded by genes with high nucleotide diversity scores including seven mTCEs encoded by six antigens in the top 10% of rapidly divergent Mtb genes encoded by these strains. Using a T cell functional assay readout, we demonstrate 62% of mTCEs tested to significantly alter CD4 T-cell IFN gamma and/or IL2 secretion with associated changes in predicted HLA-DR binding affinity: the gain of function mutations displayed higher predicted HLA-DR binding affinity and conversely mutations resulting in loss of function displayed lower predicted HLA-DR binding affinity. Most mutated antigens belonged to the cell wall/cell processes, and, intermediary metabolism and respiration families though all known Mtb proteins encoded mutations. Analysis of the mTCEs in an SNP database of 5,310 global Mtb strains identified 82% mTCEs to be significantly more prevalent in Mtb strains isolated from India, including 36 mTCEs identified exclusively in strains from India. These epitopes had a significantly higher predicted binding affinity to HLA-DR alleles that were highly prevalent in India compared to HLA-DR alleles rare in India, highlighting HLA-DR maybe an important driver of these mutations. This first evidence of region-specific TCE mutations potentially employed by Mtb to escape host immunity has important implications for TB vaccine design
One-pot synthesis of hydrophilic flower-shaped iron oxide nanoclusters (IONCs) based ferrofluids for magnetic fluid hyperthermia applications
No full textHerein, flower-shaped hydrophilic superparamagnetic iron oxide nanoclusters (IONCs) are synthesized via one pot thermolysis of iron acetylacetonate using triethanolamine (TEA) and diethylene glycol (DEG)/tetraethylene glycol (TTEG) mixtures at 9:1, 8:2 and 7:3 (v/v) ratios. The as-prepared 24-29 nm sized IONCs have displayed (i) saturation magnetization (Ms) values of similar to 68-78 emu/g, (ii) hydrodynamic diameters of similar to 95-192 nm and (iii) zeta potential values of +46 to +65 my. Due to relatively high magnetization and water solubility, IONCs (prepared using 8:2 TEA:DEG, and 8:2 & 7:3 TEA:TrEG ratios) based aqueous ferrofluids i.e. NCAFF-1, NCAFF-2, and NCAFF-3 are investigated by calorimetric magnetic fluid hyperthermia (MFH) at 0.5-8 mg/ml concentrations by exposing them to the alternating magnetic fields (AMFs, H*f similar to 2.4-9.9 GA m(-1) s(-1)). The NCAFF-3 has demonstrated excellent time dependent temperature rise (42 degrees C within 0.7-9.7 min) as compared to the NCAFF-1 and NCAFF-2. Moreover, the NCAFF-3 at 0.5 mg/ml concentration has exhibited enhanced heating efficacies with specific absorption rate (SAR) and intrinsic loss power (ILP) values of 142.4-909.4 W/g(Fe) and 4.2-14.7 nHm(2)/kg, respectively. Furthermore, the NCAFF-3 has presented better cytocompatibility, and substantially reduced proliferation capacity of HepG2 cancer cells in in vitro MFH studies. Thus, the IONCs based ferrofluids (NCAFF-3) are very promising candidates for MFH therapeutics applications. (C) 2018 Elsevier B.V. All rights reserved
Catalyst-Free, Metal-Free, and Chemoselective Transamidation of Activated Secondary Amides
No full textA simple protocol, which is catalyst-free, metal-free, and chemoselective, for transamidation of activated secondary amides in ethanol as solvent under mild conditions is reported. A wide range of amines, amino acids, amino alcohols, and the substituents, which are problematic in catalyzed transamidation, are tolerated in this methodology. The transamidation reaction was successfully extended to water as the medium as well. The present methodology appears to be better than the other catalyzed transamidations reported recently
