Charge-transfer mediated J-aggregation in red emitting ultra-small-single-benzenic -fluorophore crystals.

Red emission in crystals has been observed with an ultra-small-single-benzenic -fluorophore () with a molecular weight (MW) of only 197 Da, bettering the literature report of fluorophores with the lowest MW = 252 Da. Supramolecular extensive hydrogen-bonding and J-aggregate type centrosymmetric discrete-dimers or a 1D chain of s led to red emission ( = 610-636 nm) in crystals. Unlike in the solution phase showing one absorption band, in thin films and in crystals the transition from the S state to both the S state and S state becomes feasible.

Transforming exciton dynamics in perovskite nanocrystal through Mn doping.

Zn-alloyed CsPb(Cl/Br) perovskite nanocrystals (PNCs) have been synthesized and used as a model system for Mn doping in order to understand the effect of Mn doping on exciton dynamics. While keeping the PL emission maximum and PLQY of both PNC samples nearly the same, the radiative decay rate of the host band decreases ∼6.5 times and the non-radiative decay rate increases ∼2.

A retrospective analysis of serological & molecular testing data on dengue fever in Kolkata & adjacent districts during 2016-2019.

Background & Objectives: Regional Virus Research and Diagnostic Laboratory established at ICMR-National Institute of Cholera and Enteric Diseases (NICED) regularly receives samples for dengue screening and serotyping from patients of acute febrile illness (AFI) from Kolkata and adjacent districts. In this study, data over a three year period (August 2016-July 2019) was retrospectively analyzed to provide insight into the epidemiological trends of dengue fever in this region.

Methods: Serological screening of dengue was performed by detection of NS1 antigen and/or immunoglobulin M (IgM) antibody.

Beneficial Intrinsic Hole Trapping and Its Amplitude Variation in a Highly Photoluminescent Toxic-Metal-Free Quantum Dot.

Intrinsic hole trapping as well as hole detrapping have not been observed for any quantum dot (QD) or perovskite nanocrystal (PNC) system. Moreover, amplitude variation of intrinsic hole trapping (or detrapping) has not been reported at all for any QD or PNC system. However, for a CuInS-based core/alloy-shell (CAS) QD system, (a) both intrinsic hole trapping and detrapping have been observed and (b) very significant amplitude variations of hole trapping (∼16 to ∼42%) and hole detrapping (∼44 to 23%) have been observed.

Evaluation of adverse drug reactions of chemotherapeutic agents used in advanced non-small cell lung cancer - experience from a rural tertiary care institution in North Eastern India.

Background: Lung cancer is one of the major causes of morbidity and mortality both in developed and developing countries. Adverse drug reactions (ADRs) are inevitable, albeit unwanted aspects of cancer chemotherapeutic agents used in lung cancer.

Aim And Objectives: To determine common ADRs and the severity of ADRs of different chemotherapeutic agents used in non-small cell lung cancer (NSCLC) patients.

Medical Tourism in Tripura: Issues & Opportunities.

Medical tourism in India has an immense scope, primarily due to the unavailability or inaccessibility of medical treatment in border areas of native countries, such as Bangladesh and Myanmar. Also, the significantly low cost of complex surgery and highly skilled doctors are the most significant factors for driving tourism in India. Thus, there is a vast scope for entrepreneurship in this area.

Ultrafast dynamics and ultrasensitive single particle spectroscopy of optically robust core/alloy shell semiconductor quantum dots.

A "one-pot one-step" synthesis method of Core/Alloy Shell (CAS) quantum dots (QDs) offers the scope of large scale synthesis in a less time consuming, more economical, highly reproducible and high-throughput manner in comparison to "multi-pot multi-step" synthesis for Core/Shell (CS) QDs. Rapid initial nucleation, and smooth & uniform shell growth lead to the formation of a compositionally-gradient alloyed hetero-structure with very significantly reduced interfacial trap density in CAS QDs. Thus, interfacial strain gets reduced in a much smoother manner leading to enhanced confinement for the photo-generated charge carriers in CAS QDs.

Excitation-Energy-Dependent Photoluminescence Quantum Yield is Inherent to Optically Robust Core/Alloy-Shell Quantum Dots in a Vast Energy Landscape.

The importance of alloy-shelling in optically robust Core/Alloy-Shell (CAS) QDs has been described from structural and energetic aspects. Unlike fluorescent dyes, both Core/Shell (CS) and CAS QDs exhibit excitation-energy-dependent photoluminescence quantum yield (PLQY). For both CdSe and InP CAS QDs (with metal- and nonmetal-based alloy-shelling, respectively), with increasing excitation energy, (a) the ultrafast rise-time or relaxation-time to the band-edge increases and (b) the magnitude of the normalized bleach signal decreases.

Structure-based discovery of (S)-2-amino-6-(4-fluorobenzyl)-5,6,11,11a-tetrahydro-1H-imidazo[1',5':1,6]pyrido[3,4-b]indole-1,3(2H)-dione as low nanomolar, orally bioavailable autotaxin inhibitor.

Inhibition of extracellular secreted enzyme autotaxin (ATX) represents an attractive strategy for the development of new therapeutics to treat various diseases and a few inhibitors entered in clinical trials. We herein describe structure-based design, synthesis, and biological investigations revealing a potent and orally bioavailable ATX inhibitor 1. During the molecular docking and scoring studies within the ATX enzyme (PDB-ID: 4ZGA), the S-enantiomer (Gscore = -13.

Near-Ergodic CsPbBr Perovskite Nanocrystal with Minimal Statistical Aging.

Optical robustness, uniformity, , , etc. dictate the applicability of nanocrystals. Based on a series of multimodal statistical analyses such as the Kolmogorov-Smirnov test, Lévy statistics, etc.

Unravelling halide-dependent charge carrier dynamics in CsPb(Br/Cl) perovskite nanocrystals.

With an increasing bromide content in CsPb(Br/Cl) perovskite nanocrystals (PNCs), the steady state photoluminescence quantum yield value increases from 28% to 50% to 76%. Ultrafast transient absorption analyses reveal that the normalized band edge population increases more than two-fold on excitation at the band edge with increasing bromide content, and the hot exciton trapping time increases from 450 fs to 520 fs to 700 fs with increasing bromide content. Ultrasensitive single particle spectroscopic analyses reveal that the peak of the ON fraction distribution increases from 0.

Near-Unity Photoluminescence Quantum Yield and Highly Suppressed Blinking in a Toxic-Metal-Free Quantum Dot.

There is no literature report of simultaneously achieving near-unity PLQY (ensemble level) and highly suppressed blinking (ultrasensitive single-particle spectroscopy (SPS) level) in a toxic-metal-free QD. In this Letter we report accomplishing near-unity PLQY (96%) and highly suppressed blinking (>80% ON fraction) in a toxic-metal-free CuInS/ZnSeS Core/Alloy-Shell (CAS) QD. In addition, (i) gigantic enhancement of PLQY (from 15% (Core) to 96% (CAS QD)), (ii) ultrahigh stability over 1 year without significant reduction of PLQY at the ensemble level, (iii) high magnitude (nearly 3 times) of electron detrapping/trapping rate, and (iv) very long ON duration (∼2 min) without blinking at the SPS level enable this ultrasmall (∼3.

Extent of Shallow/Deep Trap States beyond the Conduction Band Minimum in Defect-Tolerant CsPbBr Perovskite Quantum Dot: Control over the Degree of Charge Carrier Recombination.

Perovskite quantum dots (PQDs) are known to be defect-tolerant, possessing a clean band gap with optically inactive benign defect states. However, we show that there exist significant deep trap states beyond the conduction band minimum, although the extent of shallow trap states is observed to be minimal. The extent of deep trap states beyond the conduction band minimum seems to be significant in PQDs; however, the extent is less than that of even optically robust CdSe- and InP-based core/alloy-shell QDs.

Donor/acceptor chromophores-decorated triazolyl unnatural nucleosides: synthesis, photophysical properties and study of interaction with BSA.

Much effort has been put forth to develop unnatural, stable, hydrophobic base pairs with orthogonal recognition properties and study their effect on DNA duplex stabilisation. Our continuous efforts on the design of fluorescent unnatural biomolecular building blocks lead us to the synthesis of some triazolyl donor/acceptor unnatural nucleosides via an azide-alkyne 1,3-dipolar cycloaddition reaction as a key step, which we want to report herein. We have studied their photophysical properties and found interesting solvatochromic fluorescence for two of the nucleosides.

Single step concomitant concentration, purification and characterization of two families of lipopeptides of marine origin.

The extracellular biosurfactant product secreted by a marine bacterium was concentrated and purified directly from the fermentation broth in a single step by ultrafiltration (UF) employing YM 30 kDa (UF-I) and Omega 10 kDa (UF-II) polyethersulfone membranes. The optimum operating pressure required for both membranes, UF-I and UF-II, were found to be 30 and 35 psi, respectively. The biosurfactant from the fermentation broth was recovered in higher amounts using UF-II (89%) than using UF-I (73%).

Biosurfactant production and growth kinetics of bacteria in a designer marine medium: improved physiochemical properties.

A combinatorial screening strategy was adopted for the development of a suitable medium for enhanced biosurfactant production by a marine strain. As a result, a modified marine medium (MMM) was developed, which contained urea and strontium chloride besides other salts important for the growth of marine bacteria. This medium supported growth, evident from a higher maximum growth rate value of 0.

Two accounts of the colonised "other" in South Asia re-exploring alterity.

Taking examples from South Asia, this article shows how British colonial knowledge about the non-European "other" hinged substantially on the participation of sections of that other, especially in the context of liminal groups, for whom no ready standardised formula of identification was available. Development of a colonial episteme often involved active intervention from the colonised body, thereby dispelling any strict notion of coloniser-colonised alterity and mere top-down governance. This process of identity construction took place in several arenas and also involved negotiations in courts of law, where rival sections of the amorphous colonised body fought for competing ideals of selfhood.

Microbial surfactants of marine origin: potentials and prospects.

Marine environment occupies the vast majority of the earth's surface and is a rich source of highly potent and active compounds. In recent years, microbial surfactants and emulsifiers have been reported from marine microflora. Surfactant and emulsifier molecules having diverse chemical nature such as exopolysaccharides, carbohydrate-lipid-protein complexes or glycolipopeptide, glycolipids, lipopeptides, phospholipids and ornithine lipids have been reported from various marine bacteria.

Artificial neural network modeling and genetic algorithm based medium optimization for the improved production of marine biosurfactant.

A nonlinear model describing the relationship between the biosurfactant concentration as a process output and the critical medium components as the independent variables was developed by artificial neural network modeling. The model was optimized for the maximum biosurfactant production by using genetic algorithm. Based on a single-factor-at-a-time optimization strategy, the critical medium components were found to be glucose, urea, SrCl(2) and MgSO(4).

High-performance liquid chromatography purification of biosurfactant isoforms produced by a marine bacterium.

A marine Bacillus strain produced biosurfactant during its growth in a defined glucose-containing medium. An efficient method for separation and purification of biosurfactant isoforms was developed and optimized in high-performance liquid chromatography (HPLC) by manipulating solvent gradient program and flow rates. Starting with an initial run time of 60 min, the final optimized method had a significantly reduced run time of 20 min.

Biosurfactant of marine origin exhibiting heavy metal remediation properties.

The present study was aimed at elucidating the role of biosurfactant product isolated from a marine bacterium in removing heavy metals from heavy metal containing solutions. In this study, metal removal was biosurfactant-mediated. Efficiency of metal removal depended on the concentration of the metal as well as that of the biosurfactant.

Antiadhesive action of a marine microbial surfactant.

The antiadhesive action of a lipopeptide biosurfactant from a marine bacterium was investigated. The effect of cultivation conditions on the adhesion property of few bacterial strains was studied. It was observed that the static cultures showed greater adhesion due to scarcity of oxygen.

Rapid quantification of a microbial surfactant by a simple turbidometric method.

Quantification of the biosurfactants produced by a variety of microorganisms is a time taking and difficult task due to the lack of rapid, efficient and accurate methods. This work presents a simple turbidometric method for quantification of crude biosurfactants based on their property to become insoluble at low pH values. Biosurfactants obtained from a Bacillus sp.

Substrate dependent production of extracellular biosurfactant by a marine bacterium.

The potential of a marine microorganism to utilize different carbon substrates for the production of an extracellular biosurfactant was evaluated. Among the several carbon substrates tested for this purpose, production of the crude biosurfactant was found to be highest with glycerol (2.9+/-0.

Improved bioavailability and biodegradation of a model polyaromatic hydrocarbon by a biosurfactant producing bacterium of marine origin.

Polyaromatic hydrocarbons (PAHs) are organic pollutants mostly derived from the processing and combustion of fossil fuels and cause human health hazards. In the present study a marine biosurfactant producing strain of Bacillus circulans was used to increase the bioavailability and consequent degradation of a model polyaromatic hydrocarbon, anthracene. Although the organism could not utilize anthracene as the sole carbon source, it showed better growth and biosurfactant production in an anthracene supplemented glycerol mineral salts medium (AGlyMSM) compared to a normal glycerol mineral salts medium (GlyMSM).