Generalizations of Nekrasov-Okounkov Identity

Nekrasov-Okounkov identity gives a product representation of the sum over partitions of a certain function of partition hook length. In this paper, we give several generalizations of the Nekrasov-Okounkov identity using the cyclic symmetry of the topological vertex.     

Development of new-generation low-carbon steel: Part II-wear behaviour

A new-generation unalloyed low-carbon steel (containing 0.1?wt.% C) has been recently developed by the research group of the present corresponding author through incomplete austenitisation-based cyclic ice-brine quenching possessing an exceptionally high strength (UTS?=?1.7?GPa) along with elimination of a yield point phenomenon. This is attributed to the evolution of a novel microstructure that consists of fine plate martensite crystals with a dispersion of nano-sized cementite particles and clusters. The present research work is conceived as the Part II of this investigation to establish this new-generation ultrahigh strength low-carbon steel as a unique wear-resistant steel substituting the conventional dual-phase steel along with the readily awaited in-depth correlation between wear mechanism and structural evolution. The wear behaviour of heat-treated steels is investigated against an alumina disc using a pin-on-disc tribometer. The steel subjected to incomplete austenitisation-based cyclic ice-brine quenching exhibits much better wear resistance than conventional dual-phase steel. Dominant microcutting and microploughing abrasion aggravate wear loss, especially at higher load, in dual-phase steel that inherently possesses lower matrix hardness. But, very high-surface hardness is attained in the incomplete austenitisation-based cyclic ice-brine quenched steel by virtue of a significant strain hardening of martensite matrix in between hard nano-sized cementite particles. Besides, the wear rate is not allowed to shoot up even at the highest load through the generation of hard abrasion-resistant tribo-oxide layer of Al₂FeO₄. This envisages an advent of novel wear-resistant steel as a better substitution for the dual-phase steel.     

Effects of variable blast pressures on blood flow and oxygen saturation in rat brain as evidenced using MRI

It has been recognized that primary blast waves may result in neurotrauma in soldiers in theater. A new type of contrast used in magnetic resonance imaging (MRI), susceptibility-weighted imaging (SWI), has been developed that is based on the different susceptibility levels in diverse tissues and can detect decreases in cerebral blood flow (CBF) using inferred oxygen saturation changes in tissue. In addition, a continuous arterial spin-labeled (ASL) MRI sequence was used as a direct measure of regional CBF within the brain tissue. Animals were subjected to whole-body blast exposures of various overpressures within a gas-driven shock tube. When exposed to low levels of overpressure, most rats demonstrated no obvious changes between pre- and postexposure in the conventional MR images. CBF changes measured by SWI and ASL were significantly higher for the overpressure exposed groups as compared to the sham group and tended to increase with pressure increases at the highest two pressures. In the hippocampus, all blast animals had a reduction in the CBF consistently in the range of 0-27%. In summary, low levels of primary blast pressure exposure demonstrated a significant physiologic effect to the brain up to 72 h postexposure.     

Multi-solitons of Thermophoretic Motion Equation Depicting the Wrinkle Propagation in Substrate-Supported Graphene Sheets

The paper addresses the thermophoretic motion (TM) equation, which is serviced to describe soliton-like thermophoresis of wrinkles in graphene sheet based on Korteweg-de Vries (KdV) equation. The generalized unified method is capitalized to construct wrinkle-like multiple soliton solutions. Graphical analysis of one, two, and three-soliton solutions is carried out to depict certain properties like width, amplitude, shape, and open direction are adjustable through various parameters.     

The reaction field contribution to the proton magnetic shielding of acetonitrile in some non-polar solvents

The gas-to-infinite dilution proton chemical shifts of acetonitrile in a series of non-polar, isotropic solvents have been measured. After allowance for the bulk susceptibility and van der Waals contributions, it is possible to to explain the observed shifts by the well-known reaction field theory. The existing level of experimental error in chemical shift measurement is sufficiently large that no justification exists in preferring the form of the theory based on an ellipsoidal cavity to that based on a spherical cavity. Some further observed results are given which demonstrate the existence of specific interactions between acetonitrile and each of several non-polar solvents including carbon tetrachloride.     

Synthesis, characterisation and mass spectrometric fragmentation of O-(chlorodifluoroacylated) alcohols

An indirect and uncatalysed esterification of chlorodifluoroacetic acid with polyfluoro and hydrocarbon alcohols has been developed. The method which involves the reaction between sodium chlorodifluoroacetate and alcohols in dimethylformamide (DMF) is particularly facile with polyfluorinated alcohols resulting in esters in 71-85% yield. The esters have been characterised on the basis of ¹H and ¹⁹F NMR and mass spectral data. The electron impact (EI) mass spectrometric fragmentation of these polyfluorinated esters have shown some interesting features which have been substantiated by using tandem mass spectrometry.     

Mass spectral studies on synthetic analogs of organophosphorus toxin occurring in dinoflagellate algae

A series of organophosphorus compounds related to PB-1 toxin [O,O-diphenyl N- cyclooctylphosphoramidate] occurring in dinoflagellate algae as fish toxin have been synthesized and subjected to mass spectral studies under electron ionization. The fragmentation pattern obtained for the compounds has been substantiated by performing tandem mass spectrometry experiments in product ion scan mode.     

Effect of ZnO on Photocatalytic Degradation of Rh B and Its Inhibition Activity for C. coli Bacteria

Russian Journal of Applied Chemistry - Zinc oxide (ZnO) nanoparticles have been synthesized by co-precipitation method. The structural properties like average crystallite size, lattice parameters,...     

Nematicidal natural products from the aerial parts of Lantana camara Linn

Lantanilic acid, camaric acid and oleanolic acid possessing nematicidal activity were isolated from the methanolic extract of the aerial parts of Lantana camara Linn. through bio-assay guided fractionation. These compounds exhibited 98%, 95% and 70% mortality respectively against root-knot nematode Meloidogyne incognita at 0.5% concentration. Conventional nematicide furadan showed 100% mortality at this concentration.