Defining topologigical equivalences in macromolecules

We describe a completely automated and objective method fordefining topological equivalents in macromolecules. The methodis based on well established techniques for identifying topologicallyand topographically equivalent atoms in small molecules andhas been used in structural alignment of proteins and RNA molecules,and to extract fragments of molecules (protein secondary structuresand RNA and DNA double helices) from structural databases consistentwith some specified template structure.     

Reactivity of a high ash Indian coal (Manuguru, Godavari Valley) towards CO2

In a study of C-CO₂ reaction kinetics by thermogravimetric analysis (TGA), the effect of diffusion resistance is uncoupled using a global reaction rate model normally employed in gasifier design calculation. For intrinsic rate, a Langmuir-like model is proposed for the first time. The estimated activation energy for the reaction is in agreement with reported values. It is found that the entropy of disintegration of the carbon-ash matrix in char is highly negative (for char from Indian coals). This indicates, not surprisingly, that carbon and ash in char form a highly interactive phase.     

Selecting the optimal focus measure for autofocusing anddepth-from-focus

A method is described for selecting the optimal focus measure with respect to gray-level noise from a given set of focus measures in passive autofocusing and depth-from-focus applications. The method is based on two new metrics that have been defined for estimating the noise-sensitivity of different focus measures. The first metric-the autofocusing uncertainty measure (AUM)-is useful in understanding the relation between gray-level noise and the resulting error in lens position for autofocusing. The second metric-autofocusing root-mean-square error (ARMS error)-is an improved metric closely related to AUM. AUM and ARMS error metrics are based on a theoretical noise sensitivity analysis of focus measures, and they are related by a monotonic expression. The theoretical results are validated by actual and simulation experiments. For a given camera, the optimally accurate focus measure may change from one object to the other depending on their focused images. Therefore, selecting the optimal focus measure from a given set involves computing all focus measures in the set     

Rare earth-transition metal alloy permanent magnet materials: 1960–1985

Rare earths, primarily light rare earths, either alone or in combination with other rare earths, as in misch metal, alloyed with cobalt or iron, constitute a unique new class of permanent magnet materials with outstanding coercivity and other magnetic properties. These materials represent the first serious alternative to the alnicos and ferrites, discovered earlier. The intensity of interest in this field may be judged by the presence of over 800 publications which have appeared in the 25 years since their discovery and by the fact that the publication rate remains unabated. The present bibliography includes a listing of references by year and indexes based on subject, material and author.     

Thermal Expansion of Compounds of Zircon Structure

The thermal expansion behavior of 13 members of ABO₄ compounds of the zircon family is examined in terms of crystal chemical (size, charge, and mass of cations) and crystallographic ( a and c ) parameters. The systematic trend in the thermal expansion coefficients, α_a and α_c, with the ionic radii, r _A and r _B, can be explained in terms of the unique arrangement of M-O polyhedra along a and c directions of this lattice. In the zircon structure, edge-sharing ZrO₈ dodecahedra form a chain along the a direction while the chain along the c direction consists of alternate edgesharing SiO₄ tetrahedra and ZrO₈ triangular dodecahedra. Substitution in the A sites affects a and α_a more than c and α_c and the reverse is true for replacements in the B sites. Unequal valencies on the A and B sites affect thermal expansion coefficients, particularly α_c.     

Carbon nanotube-zirconium dioxide hybrid for defluoridation of water

This study presents the synthesis of zirconia/multi-walled carbon nanotube (ZrO2/MWCNTs) hybrid as a novel sorbent for water defluoridation. The synthesis was facilitated by the high degree of functionalization of MWCNTs using a microwave assisted process. In the final product, nearly 3% of the carbon atoms were attached to ZrO2. The ZrO2/MWCNTs were effective in fluoride removal and mechanistic aspects of the process are presented. The research findings highlight the potential application for the use of MWCNT hybrids in environmental remediation.     

Asymmetric Dimethylarginine in Chronic Obstructive Pulmonary Disease (ADMA in COPD)

l-Arginine metabolism including the nitric oxide (NO) synthase and arginase pathways is important in the maintenance of airways function. We have previously reported that accumulation of asymmetric dimethylarginine (ADMA) in airways, resulting in changes in l-arginine metabolism, contributes to airways obstruction in asthma and cystic fibrosis. Herein, we assessed l-arginine metabolism in airways of patients with chronic obstructive pulmonary disease (COPD). Lung function testing, measurement of fractional exhaled NO (FeNO) and sputum NO metabolites, as well as quantification of l-arginine metabolites (l-arginine, l-ornithine, l-citrulline, ADMA and symmetric dimethylarginine) using liquid chromatography-mass spectrometry (LC-MS) were performed. Concentrations of l-ornithine, the product of arginase activity, correlated directly with l-arginine and ADMA sputum concentrations. FeNO correlated directly with pre- and post-bronchodilator forced expiratory volume in one second (FEV₁). Sputum arginase activity correlated inversely with total NO metabolite (NO_x) and nitrite concentrations in sputum, and with pre- and post-bronchodilator FEV₁. These findings suggest that ADMA in COPD airways results in a functionally relevant shift of l-arginine breakdown by the NO synthases towards the arginase pathway, which contributes to airway obstruction in these patients.     

Maximum power point tracking controller implementation in multiple input converter for effective solar energy harvesting using maximum power point resistance method

Solar energy is widely acknowledged as one of the most promising renewable energy sources for addressing future electrical energy demands. Photovoltaic modules (PVms) convert solar energy into electrical energy and are highly sensitive to nonlinear changes in environmental circumstances, which in turn affect the generation of electricity from the PVms. The module-level maximum power point tracking (MPPT) of PVms using multiple input converters (MICs) is the effective and cost-efficient method among all the methodologies and techniques. MICs, on the other hand, suffer from a cross power-sharing difficulty due to their modular design, which implies that the individual cells that make up the device impact on each other's power-sharing operation. The solution to which have been ignored in the literature. The objective of this paper is to employ the maximum power point resistance (MPPR) approach to determine an appropriate duty ratio range for the proposed MIC while taking into consideration the cross effect of different cells. Steady-state, power loss, and efficiency analysis of the proposed MIC structure with less component count have been included. The proposed approach has been validated experimentally and further, a comparative analysis with recently reported various approaches has also been included to prove the suitability of the proposed approach.     

Omicron: Understanding the Latest Variant of SARS-CoV-2 and Strategies for Tackling the Infection

The new variant of concern of SARS-CoV-2, namely Omicron, has triggered global fear recently. To date, our knowledge of Omicron, particularly of how S glycoprotein mutations affect the infectivity of the virus and the severity of the infection, is far from complete. This hinders our ability to treat the disease and to predict the future state of SARS-CoV-2 threats to well-being and economic stability. Despite this, efforts have been made to unveil the routes of transmission and the efficiency of existing vaccines in tackling Omicron. This article reviews the latest understanding of Omicron and the current status of the use of vaccines and drugs for infection control. It is hoped that this article can offer insights into the development of more effective measures to tackle the pandemic.