Synthesis,Characterization, and Possible Applications of ZnO Nanocrystals

ZnO nanocrystals are synthesized using the quenching method. The properties of the grown nanocrystals are studied using ultraviolet-vis spectroscopy, x-ray diffraction, photoluminescence, electron diffraction, energy dispersive x-ray spectroscopy, and high resolution transmission electron microscopy. Current-voltage characteristics of the prepared samples are studied for investigating the possible application of the samples as switch and memristor.     

Fiber-optic beam shaper based on multimode interference

A new method of fiber-optic based beam shaping is investigated both numerically and experimentally. A cylindrically symmetric method of lines (MoLs) is developed to simulate the device. The device is fabricated by fusion splicing a predetermined length of multimode fiber (MMF) to a single-mode fiber. The multimode interference (MMI) effects create ring-shaped field profiles at certain positions inside the MMF. The shaped beam can be used in medical applications requiring particular irradiation patterns.     

Thermal analysis for study of influence of Cd,In, and Sb on glass transition kinetics in glassy Se80Te20 alloy using DSC technique

In this paper, we have incorporated Cd, In, and Sb in glassy Se₈₀Te₂₀ alloy to see the metal-induced effect of these additives on its glass network and kinetic properties. Specifically, we report results of systematic calorimetric measurements to study the glass transition kinetics. The glass transition behavior of glassy Se₈₀Te₂₀ and glassy Se₈₀Te₁₀M₁₀ (M = Cd, In, Sb) alloys has been analyzed by differential scanning calorimetric technique at various heating rates. The activation energy (E _g) of glass transition was determined using different kinetic models. Analysis of experimental data reveals that E _g varies with the additive elements. The value of various kinetic parameters such as thermal stability, Hruby number, and fragility index has been calculated in non-isothermal mode.     

Impact of Targeted Specific Antibiotic Delivery for Gut Microbiota Modulation on High-Fructose-Fed Rats

The objective of present investigation was to study the effect of gut microbiota alteration by oral administration of targeted delivery of pH sensitive cefdinir microspheres to high-fructose-fed (HFD) rats. Rats were fed with a high-fructose diet with or without cefdinir microsphere administration for 30 days. The fecal microbiota community, oral glucose tolerance, the markers of liver injury, plasma and hepatic lipids profile, and histological evaluation were investigated. The levels of blood glucose, liver injury markers, lipid profile in plasma and liver, and fat tissue were significantly increased in high-fructose-fed rats. However, after pH-sensitive cefdinir microsphere administration, the elevation of these parameters was significantly suppressed. Cef EL significantly lowered the increased AST (p?<?0.05) and ALT (p?<?0.001) levels in HFD group. There is a significant lower (p?<?0.01) AUC_glucose level in Cef EL group than HFD group The histological changes in the liver and the small and large intestines were more profound in HFD group as compared to cefdinir-treated HFD and control groups. Feeding of cefdinir microsphere sustained lactobacilli and bifidobacteria and significantly decreased (p?<?0.05) the number of Enterobacteriaceae induced by HFD. Experimental evidences demonstrated that the effectiveness of pH-specific cefdinir microsphere on reducing insulin resistance and development of metabolic changes in high-fructose-fed rats and suggested that it may be a promising therapeutic agent in treating type 2 diabetes. Intestinal-targeted antibiotic delivery needs to be further explored for its therapeutic applications.     

BiVO4/TiO2 core-shell heterostructure: wide range optical absorption and enhanced photoelectrochemical and photocatalytic performance

In the present study, pristine BiVO₄, TiO₂ and BiVO₄/TiO₂ core-shell heterostructured nanoparticles are prepared by hydrothermal methods and studied for structural, morphological, optical, photoelectrochemical water splitting and photocatalytic degradation of methylene blue as an organic pollutant. Both pristine BiVO₄ and TiO₂ exhibit poor PEC and PC performance under visible light illumination. However, an enhanced PEC and PC activity in BiVO₄/TiO₂ core-shell heterostructure is observed due to high solar energy absorption and superior charge separation properties in core-shell nanoparticles. The photoelectrode prepared using BiVO₄/TiO₂ core-shell nanoparticles exhibit a photocathode behavior and produced cathodic photocurrent, however, the pristine BiVO₄ and TiO₂ photoelectrodes act as photoanode and produced anodic photocurrent. This behavior of change in current direction is also observe in the Mott-Schottky analysis where the BiVO₄/TiO₂ core-shell nanoparticles photoelectrode exhibits the positive slow showing p-type semiconducting behavior. The change in cathodic photoresponse in core-shell nanoparticles in comparison to anodic photoresponse of BiVO₄ and TiO₂ nanoparticles is explained in terms of the variations in the work function values. These results highlight the advantages of core-shell nanoparticle of suitable materials for photocatalytic and photoelectrochemical applications.     

Nitrenium Salts in Lewis Acid Catalysis

Molecular compounds featuring nitrogen atoms are typically regarded as Lewis bases and are extensively employed as donor ligands in coordination chemistry or as nucleophiles in organic chemistry. By contrast, electrophilic nitrogen‐containing compounds are much rarer. Nitrenium cations are a new family of nitrogen‐based Lewis acids, the reactivity of which remains largely unexplored. In this work, nitrenium ions are explored as catalysts in five organic transformations. These reactions are the first examples of Lewis acid catalysis employing nitrogen as the site of substrate activation. Moreover, these compounds are readily accessed from commercially available reagents and exhibit remarkable stability toward moisture, allowing for benchtop transformations without the need to pretreat solvents.     

Thermal Etching on Calcite Cleavages

Thermal etch pits are observed on calcite cleavages at very small range of temperatures in atmosphere. Different characteristics such as nonmovement of cleavage lines and dislocations, thermal percussion by gas molecules, are observed in thermal etching. It is found that chemical and thermal etching are not the same process for calcite cleavage etching. The origin of thermal etch pits is not at dislocations intersecting the cleavage surfaces.     

Chemical Etching of Calcite Cleavages by Diluted Solutions

Very low concentration of mineral acids and monocarboxylic acid (less then 0.001%) produces triangular etch pits on calcite cleavages at dislocations intersecting the surface. The orienation of triangular etch pits is opposite with respect to percussion mark on calcite cleavages. This may be due to opposite process of percussion and reaction at very low concentrations. When percentage of water is slightly decreased in both above acids, rhombic etch pits were formed. The non-coincidence of depth points and geometerical centres of rhombic etch pits are explained. The similarity of shape cycle will not hold at higher concentrations.