Ultra-narrow and widely tunable Mn^(2+) Emission from Single Nanocrystals of ZnS-CdS alloy

Extensively studied Mn-doped semiconductor nanocrystals have invariably exhibited photoluminescence (PL) over a narrow energy window of width <= 149 meV in the orange-red region and a surprisingly large spectral width (>= 180 meV), contrary to its presumed atomic-like origin. Carrying out emission measurements on individual single nanocrystals and supported by ab initio calculations, we show that Mn PL emission, in fact, can (i) vary over a much wider range (~ 370 meV) covering the deep green-deep red region and (ii) exhibit widths substantially lower (~ 60-75 meV) than reported so far, opening newer application possibilities and requiring a fundamental shift in our perception of the emission from Mn-doped semiconductor nanocrystals.Comment: 5 pages, 5 figure

Three-Dimensional Hydrogel Bioprinting Technology as a Scaffold of Novel Drug Delivery and Biomedical Devices: A Comprehensive Review

Polymer hydrogel used as computer-aided, non-biological arsenal utilize as a drug delivery vehicle overthe past few years.New advances in three-dimensional (3D) bioprinting technology have created new opportunitiesfor the use of hydrogel polymer-based medication delivery systems. 3D printing can deliver the ideal shapes or changecapabilities under specific circumstances which have a better adaptation to physiological function. The accuracy of 3Dprinting technology was significantly higher than that of conventional production techniques.A model bioink acquireproper physicochemical characteristics (mechanical and rheological) and biological properties important for proper functioning.It acts as additive manufacturing with complex spatial structure in biomedical research. In this review, we outlined the currentdevelopments in 3D printed polymer hydrogels as delivery and other platforms

Role of double-hybrid density functionals and correlation consistent basis sets in OCS-hydrocarbon complexes

1369-1377<span style="font-size:9.0pt;mso-bidi-font-size: 12.0pt;font-family:" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-us;mso-fareast-language:ja;mso-bidi-language:="" ar-sa"="" lang="EN-US">The role of five newly developed double hybrid density functionals (DHDFs) in conjunction with Dunning’s correlation consistent aug-cc-pVDZ, aug-cc-pVTZ and aug-cc-pVQZ basis sets has been investigated to describe the weak interaction of the T-shaped isomer of OCS-C2H2 <span style="font-size:9.0pt;mso-bidi-font-size:12.0pt; font-family:" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-us;mso-fareast-language:ja;mso-bidi-language:="" ar-sa"="" lang="EN-US">and <span style="font-size:9.0pt;mso-bidi-font-size: 12.0pt;font-family:" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:="" ar-sa"="" lang="EN-US">OCS-C2H4 weakly bound van der Waals (vdW) complexes. Structure, equilibrium distances, interaction, potential energy curves and binding energy or depth of the potential well of both the complexes have been studied in detail using the DHDFs theories with these basis sets. A comparison has been made between our present results and previous theoretical and experimental values. The potential energy curves are drawn to substantiate the calculated values. Calculated equilibrium distances are the same as those reported by experiments. The <span style="font-size:9.0pt; mso-bidi-font-size:12.0pt;font-family:" times="" new="" roman","serif";mso-fareast-font-family:="" advot9b12cd41;color:black;mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="" lang="EN-US">components of interaction energy of both the OCS-hydrocarbon complexes are also calculated using localized molecular orbital energy decomposition analysis. <span style="font-size:9.0pt; mso-bidi-font-size:12.0pt;font-family:" times="" new="" roman","serif";mso-fareast-font-family:="" advmyriad-rs;color:black;mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="" lang="EN-US">The results suggest that amongst the five DHDFs only the mPW2PLYP DHDF with aug-cc-pVQZ basis set gives the best results as compared to other DHDFs. The results provide an insight into the computational methods and basis sets for such weakly bound complexes. It also reveals that both method and basis set are important to obtain accurate results for such weakly bound complexes.</span

Structural perturbation of proteins in low denaturant concentrations

84-89The presence of very low concentrations of the widely used chemical denaturants, guanidinium chloride and urea, induce changes in the tertiary structure of proteins. We have presented results on such changes in four structurally unrelated proteins to show that such structural perturbations are common irrespective of their origin. Data representative of such structural changes are shown for the monomeric globular proteins such as horseradish peroxidase (HRP) from a plant, human serum albumin (HSA) and prothrombin from ovine blood serum and for the membrane-associated, worm-like elongated protein, spectrum from ovine erythrocytes. Structural alterations in these proteins were reflected in quenching studies of tryptophan fluorescence using the widely used quencher acrylamide. Stern-Volmer quenching constants measured in presence of the denaturants, even at concentrations below 100 mM, were higher than those measured in absence of the de naturants. Both steady-state and time-resolved fluorescence emission properties of tryptophan and of the extrinsic probe PRODAN were used for monitoring conformational changes in the proteins in presence of different low concentrations of the denaturants. These results are consistent with earlier studies from our laboratory indicating structural perturbations in proteins at the tertiary level, keeping their native-like secondary structure and their biological activity more or less intact

In-silico and in-vivo evaluation of comparative enhanced neurogenic performance by energy drinks

Objective: &nbsp;In the present society, the energy drinks (EDs) are used by general public and mainly by the sports persons. Though the caffeine content of EDs is creating health consequences on excess consumption, the present study targets their health benefits on central nervous system (CNS) focusing antidepressant and cognitive potentiality. The most typically used EDs have been selected for the study such as Red Bull, Monster and Enerzal for the present research. Methodology: The study started with in-silico studies to get information about the neurological receptor binding of the major and common chemical components of the EDs. The antidepressant study of energy drinks was carried out following FST (Forced Swim Test) and TST (Tail suspension test) methods. Their cognition effect was assessed by using Y-maze apparatus. Further, their mechanism of action was evaluated by estimating their effect on brain dopamine and serotonin level. Results: In-silico study revealed the enhanced agonistic binding of the major common components of the EDs to D2 and serotonin receptors. Further their significant (p&lt;0.001) antidepressant property was estimated both in tail suspension and forced swim tests along with significant cognitive property.&nbsp

DFT-based characterization of double β-B-Bagostic interaction in model Ti-borane complexes

Simultaneous activation of two intramolecular B-H bonds in Ti-borane complexes, designated as double β-B-agostic interaction, has been investigated using state-of-the-art DFT techniques and further tuned by coordination number, systematic substitution, and conformational changes. A series of (L)y(M)zTi-NH2BH3 [L=Cl-, M=H2O, y+z=3-6] compounds have been considered to investigate the electronic and structural properties of double β-B-agostic interaction. Our analysis infers that the strength, pattern, and symmetricity of the B-H bond activation depend on each tuning parameter mentioned above; in extreme cases, a few complexes show single B-H activation. It has been noticed that the extent of activation of B-H bonds has a proportional relationship with B-H bond distance and an inversely proportional relationship with Ti-H bond distance, which is further confirmed through QTAIM analysis. The formation of partial covalent character between Ti and H centers illustrates the impact of metal on the generation of double β-B-agostic interaction. Overall, the concept of double β-B-agostic interactions encourages the researcher to study novel catalytic activities related to metal-borane complexes through more than one B-H bonds activation

A A BRIEF DESCRIPTION OF COVID-19 PULMONARY VIRAL INFECTION AND REPURPOSING OF DRUGS FOR ITS TREATMENT

A novel coronavirus disease, which is transmitted from human to human has quickly become the cause of the current worldwide health crisis. This virus is also known as SARS coronavirus belongs to the Coronaviridae family of viruses. The recent outbreak of acute respiratory disorders starting in Wuhan, China is found to be caused by this virus. The condition caused by it, known as COVID-19 has spread very rapidly all over the world causing so many death. This led WHO on Mar 11, 2020, to designate it as a global pandemic. An update on the history, etiology, epidemiology, pathophysiology and preventive methods for COVID-19 such as masking, quarantine, and social distancing are discussed in this paper. Repurposed drugs, antibodies, corticosteroids, vaccination and plasma transfusion are among the treatments explained in the study. Finally, the study discusses India’s COVID vaccination programme. The major aspects of this entire review are to describe COVID-19 infection, its prevention and treatment approach

Mechanistic Insight into the Molecular TiO₂‑Mediated Gas Phase Detoxication of DMMP: A Theoretical Approach

The detoxication of DMMP (dimethyl methylphosphonate) mediated by molecular TiO₂ has been investigated computationally using density functional theory (DFT). From our previous studies, it is evident that the unimolecular detoxication of OPCs (organophosphorus compounds) is kinetically unfeasible at room temperature due to the significantly high activation barrier. Thus, the aim of our work is to find out whether molecular TiO₂ can make any significant impact on the kinetic feasibility of the detoxication processes or not. Here, we have identified a total of three detoxication pathways, where in the first step the detoxication occurs through H-abstraction with the assistance of TiO₂, and in the second step, the titanium complex is separated from the respective phospho-titanium complexes. The outcomes reveal that the TiO₂-mediated detoxication pathways are at least 20.0 kcal/mol more favorable than their respective unimolecular pathways and that among them, the α-H-mediated isomerization is found to be the most feasible pathway. When the separation of a titanium complex is under consideration, the double H₂O-assisted mechanism is found to be the favored pathway. Overall, the entire work provides a widespread idea about the efficiency of molecular TiO₂-assisted detoxication of DMMP, which can be well applicable to other OPCs also

Exploration of Binding Interactions of Cu²⁺ with d‑Penicillamine and its O- and Se- Analogues in Both Gas and Aqueous Phases: A Theoretical Approach

We have theoretically explored the entire binding phenomena of d-penicillamine and its O- and Se-analogues with Cu²⁺ in both gas and aqueous phases. At first, a brief conformational analysis has been performed via −XH and −COOH rotations to investigate such conformers that are suitable for binding in both bidentate as well as tridentate fashions. The stability of each bidentate and tridentate complex is determined on the basis of relative energy (Δ<i>E</i>) and gas phase metal ion affinity (MIA) along with the bonding analysis by using atoms in molecule theory. The effect of conformational change on the stability of the complexes is also examined thoroughly. By analyzing the MIA values, we have shown that the side chain substitution makes an impact on the binding process. To delve into the binding phenomena in aqueous phase, we have introduced both the first and second hydration sphere models. In first hydration sphere model, to realize the precise effect of water molecules we have considered stable octahedral hexa-aqua copper complex, [Cu­(H₂O)₆]⁺² and accordingly substituted water molecules depending on the bidentate or tridentate nature of the chelating agents. The influence of bulk water molecules on the energetics and geometries of the first hydrated sphere complexes have also been investigated by employing second hydration sphere model assuming physiological pH through the implementation of implicit COSMO and polarizable continuum models, respectively. In the second hydration sphere model, the zwitterionic structures of the amino acids and their side chain deprotonated forms are also included to study the binding phenomena with Cu²⁺. The complete work furnishes both the binding properties and the energetics of the copper–artificial amino acid complexes in both gas and aqueous phases that will reflect a realistic overview of the entire binding phenomena