Modeling D-Region Ionospheric Response of the Great American TSE of August 21, 2017 from VLF signal perturbation

Solar eclipse is an unique opportunity to study the lower ionospheric variabilities under a controlled perturbation when the solar ultraviolet and X-ray are temporally occulted by the lunar disk. Sub-ionospheric Very Low Frequency (VLF) radio signal displays the ionospheric response of solar eclipse by modulating its amplitude and phase. During the Total Solar Eclipse (TSE) on August 21, 2017 in North America, data was recorded by a number of receivers as presented in public archive. Out of these, two receiving stations YADA in McBaine and K5TD in Tulsa could procure a reasonable quality of noise free data where the signal amplitude was clearly modulated due to the eclipse. During the lunar occultation, a C3.0 solar flare occurred and the signal received from Tulsa manifested the effect of sudden ionization due to the flare. The VLF amplitude in Tulsa shows the effect which is generally understood by superimposing effects of both the solar eclipse and flare. However, the signal by YADA did not perturb by the solar flare, as the flaring region was totally behind the lunar disk for the entire period. We numerically reproduced the observed signal amplitude variation at both the receiving locations by using Wait's two component D-region ionospheric model and the well-known Long Wavelength Propagation Capability (LWPC) code. The perturbed electron density for both the cases is computed which matches satisfactorily with the true ionospheric conditions.Comment: 22 pages, 11 Figures, Submitted in Advances in Space Research (ASR) on 1 Jan. 201

Evaluation of saturated hydraulic conductivity from soil properties in an Inceptisol using different land cover and depths

hree soil profiles from Regional Research Station of Bidhan Chandra Krishi Viswavidyalaya, Gayeshpur situated in New Alluvial zone of Nadia district, West Bengal were studied to assess the predictability of the hydraulic conductivity of the soil as influenced by different physical and chemical and properties of cultivated and forest land. The various statistical procedures were employed on the measured laboratory based data for comprehensive agree-ment of dependent hydraulic conductivity of soils as a model function of independent soil variables that is likely to be useful for different land cover systems. Soils are neutral in reaction, silty clay to silty clay loam in nature. Forest soil contained greater organic carbon (OC) (5.9 ± 0.16 g kg-1) compared to cultivated soil (4.4 ± 0.34 g kg-1). Jhau plan-tation recorded the highest value (6.8 g kg-1) of OC due to soil texture and cation exchange capacity (CEC). Soil hydraulic conductivity was greater in soil for cabbage and Sagun tree among the cultivated and forest soil studied with values 2.80 and 1.10 cmh -1. Correlation study showed a positive and negative relation with hydraulic conductiv-ity for sand (r= 0.68; P > 0.05) and clay (r= - 0.71; P > 0.05) respectively. Further, principal component analysis con-cluded that addition of bulk density with clay and sand can predict the hydraulic conductivity for different land uses

Synthesis and reactivity of a 9-membered azaenediyne: importance of proximity effect in N-alkylation

Synthesis of a 9-membered azaenediyne has been achieved for the first time via intramolecular N-alkylation; the importance of proximity of the reacting centres via cobalt carbonyl complexation of the acetylenic moiety and not the activation of propargylic carbon has been demonstrated

A novel approach for deducing the mass composition of cosmic rays from lateral densities of EAS particles

A Monte Carlo (MC) simulation study of cosmic ray (CR) extensive air showers (EAS) has been carried out in the energy regime of the KASCADE experiment. From the characteristics of lateral distributions of electrons and muons of simulated EAS, some important EAS observables are extracted by a novel approach, and their CR mass-sensitivity is demonstrated. The study takes into account the issue of the experimental lateral density profiles of EAS electrons and muons after introducing the notion of the local age and segmented slope parameters, aimed to extract information on CR mass composition from observed data. The estimated lateral shower age and slope from the analysis of the KASCADE data (KCDC) agrees with the idea of a gradual change of CR mass composition from light to heavy around the knee.Comment: 8 pages, 10 figures, Accepted in a Journa

Chemistry of enediynyl azides: activation through a novel pathway

The spontaneous activation of a nonaromatic enediynyl azide under ambient conditions has been demonstrated. The aromatic enediyne followed the expected cycloaddition with the alkene in the neighbouring arm to form a stable bridged bicyclic enediyne

Asymmetric gating of a homopentameric ion channel GLIC revealed by cryo-EM

Pentameric ligand-gated ion channels (pLGICs) are vital neurotransmitter receptors that are key therapeutic targets for neurological disorders. Although the high-resolution structures of these channels have been elucidated, capturing their dynamic conformational transitions remains challenging due to the transient nature of intermediate states. In this study, we investigated a prokaryotic proton-gated pLGIC, GLIC. In our cryo-EM data at pH 4.0, we identified and segregated asymmetric particles, which we precisely aligned to resolve high-resolution structures of several previously unresolved asymmetric intermediate states, in addition to symmetric closed and open states. Detailed structural analysis revealed systematic conformational changes at individual subunits driving the channel opening. Molecular dynamics simulations were used to assign the functional states. We further examined the roles of the F116 and Y251 residues, located at the domain interface, playing a central role in interdomain communication. In addition, patch-clamp experiments on GLIC I240A and L241A mutants, located in the M2 helix, demonstrated their importance in channel gating. Together, these results shed light on the sequential and asymmetric conformational transitions that occur during GLIC activation, offering a deeper mechanistic understanding of asymmetric gating in pLGICs

Metal-organic framework as nanocarriers for agricultural applications: a review

Agrochemicals are substances used to promote plant growth and eradicate pests; and are essential to meeting the world food demand both qualitatively and quantitatively. Unfortunately, their extensive usage has resulted in certain significant problems, i.e., soil contamination, bioaccumulation, and the development of pest resistance. Consequently, there is a need for a reduced and more regulated usage of agrochemicals. The development of sustainable nanomaterials is encouraged in agricultural nanotechnology to minimize the usage of conventional fertilizers, herbicides, and pesticides. Metal-organic Framework (MOF)s are porous materials made of functional organic ligands and metal nodes or clusters connected by covalent bonds. Researchers are becoming increasingly interested in using MOF in a variety of sectors. The features of engineered MOFs have the potential to be an optimal strategy for producing impressively unique results in agricultural research. They also have advantages in terms of biocompatibility and biodegradability, which can be leveraged to boost the efficiency of traditional agrochemicals administration. Controlled release of agrochemicals offers an innovative solution to decrease the nutrient uptake rates and contamination of the environment. The application of MOF nanoparticles as nanocarriers to modify the loading and release properties of agrochemicals is particularly highlighted in this review

Structures and regulation of coupling subunit F and the arrangement of the subunit DF-assembly in the Saccharomyces cerevisiae v1vO ATPase

V-ATPases play an important role in the acidification of intracellular compartments such as lysosomes, endosomes, Golgi complexes and secretary granules. The V-ATPases are composed of at least 14 separate gene products, with many of these subunits present in multiple isoforms. The proposed subunit stoichiometry of V1 is A3:B3:C:D:E3:F:G3:H1 (1). The integral VO domain contains six different subunits in a stoichiometry of a:d:c4-5:c’:c”:e. V-ATPases exist in a dynamic equilibrium between fully assembled complexes and reversibly disassembled V1 and VO subcomplexes. Depending on the energy status of the cell, this equilibrium can be rapidly shifted (2). Vacuolar ATPases use the energy derived from ATP hydrolysis, catalyzed in the A3B3 sector of the V1 ATPase to pump protons via the membrane-embedded VO sector. The energy coupling between the two sectors occurs via the so-called central stalk, to which subunit F belongs. In the present study, the low resolution structure of recombinant subunit F (VMA7p) of the eukaryotic V-ATPase from Saccharomyces cerevisiae has been analyzed by small angle X-ray scattering (SAXS). The protein is divided into a 5.5 nm long egglike shaped region, connected via a 1.5 nm linker to a hook-like segment at one end. Circular dichroism spectroscopy revealed that subunit F comprises of 43% -helix, 32% -sheet and a 25% random coil arrangement. To determine the localization of the N- and C-termini in the protein, the C-terminal truncated form of F, F1-94 was produced and analyzed by SAXS. Comparison of the F1-94 shape with the shape of the entire subunit F showed the missing hook-like region in F1-94, supported by the decreased Dmax value of F1-94 and indicating that the hook-like region consists of the C-terminal residues (3). The NMR solution structure of the C-terminal peptide, F90-116, was solved, showing an α-helical region between residues 103-113 (3). The F90-116 solution structure fitted well in the hook-like region of subunit F (3). In order to understand the structural features of F1-94 at the atomic level, X-ray crystallography was performed. The crystal structure of F1-94 reveals a Rossmann fold with alternating β-strands and α-helices (4). Elliptical shaped F1-94 has four β-strands which are surrounded by four α-helices. F1-94 contains two important loops spanning between α1-β2 (26GQITPETQEK35) and α2-β3 (60ERDDI64) which are present only in eukaryotic F subunits. Multiple sequence alignments of subunit F show that the 60ERDDI64 loop is highly conserved among the eukaryotic V-ATPases (4). NMR spectroscopy of the entire subunit F confirmed the secondary structural features of the crystallographic structure F1-94 in solution as well as the C-terminal peptide, F90-116. The heteronuclear NOE experiment shows that subunit F has a rigid core in the N-terminal domain, whereas α1 and α5 are more flexible in the solution (4). To understand the cross-talk between central stalk subunits with the neighboring subunits, a DF-heterodimer was generated. The DF-heterodimer binds to subunit d with a dissociation constant (Kd) of 52.9 µM as determined by ITC experiment (4). The DF-heterodimer yielded crystals with a dimension of 0.13 mm x 0.10 mm x 0.04 mm, which diffracted maximum to 5 Å.DOCTOR OF PHILOSOPHY (SBS

An Analysis of Financial Performance of Pharmaceutical Industry in India - A Study on NSE Listed Pharmaceutical Companies

When the economy of entire world has been shattered by the sudden strike of Covid-19 Pandemic, Indian economy is still running with the help of Pharmaceutical Industry. It acts as a strong backbone of the economy. According to IKON Marketing Consultants! estimates, in the fiscal year, 2020-21 the Indian pharma industry is estimated to be worth $43 billion. In the last fiscal itself, the sector contributed around 1.72 per cent to the country’s GDP, making a significant mark. It was around one per cent a decade ago. In the case of exports, drugs and pharma products have recorded positive growth of 24.89 per cent during September 2020 vis-a-vis September 2019 amongst a few other commodity groups. The export of pharma products stood at$ 7,595 million and it remains the second-highest contributor with 7.79 per cent of total exports during April — Aug 2020, the Ist first being minerals with 8.94 per cent. Therefore, this study analyzes the present scenario of Indian Pharmaceutical Industry in terms of their financial performance.</jats:p