An Anisotropic Cosmological Model in Self-creation Cosmology

The paper presents an exact solution of spatially homogeneous and anisotropic cylindrically symmetric cosmological model in Barber’s second self-creation theory of gravitation in the presence of perfect fluid with pressure equal to energy density. Some physical properties of this model are also discussed.     

An Anisotropic Homogeneous Cosmological Model in a Modified Brans-Dicke Cosmology

Adding the cosmological term, which is assumed to be variable in Brans-Dicke theory we have discussed about a spatially homogeneous and anisotropic cosmological model corresponding to Bianchi type-I solution. The physical and geometrical properties of this model has been discussed. Finally this model has been transformed to the original form (1961) of Brans-Dicke theory (including a variable cosmological term).     

A New Highly Sensitive and Selective Fluorescent Cadmium Sensor

Condensation product (L) of salicylaldehyde and semicarbazide behaves as a fluorescent sensor for Cd²⁺ ion, in 1:1 DMSO:H₂O, over Mn²⁺, Fe²⁺, Ni²⁺, Co²⁺, Cu²⁺, Pb²⁺ and Hg²⁺ ions. The emission peak of L at λ_max = 520 nm, on excitation with 420 nm wavelength photons, showed an enhancement in intensity of ca 60-fold when interacted with Cd²⁺ ion. The intensity was however found to remain unaltered when interacted with metal ions—Mn²⁺, Fe²⁺, Ni²⁺, Co²⁺, Cu²⁺, Pb²⁺ and Hg²⁺. The intensity increases by approximately 20 fold on interaction with Zn²⁺ ion. The increase in the fluorescent peak can be explained on the basis of photo induced electron transfer (PET) mechanism. A 1:1 complexation between Cd²⁺ and L with log β = 4.25 has been proved.     

Ultrasound assisted green synthesis of bis(indol-3-yl)methanes catalyzed by 1-hexenesulphonic acid sodium salt

1-Hexenesulphonic acid sodium salt as catalyst for green synthesis of bis(indol-3-yl)methanes was described. The reaction of indole with various aldehydes in water using ultrasound irradiation at ambient temperature for appropriate time using 1-hexenesulphonic acid sodium salt furnish the desired product in good to excellent yield. Utilization of aqueous medium, simple reaction conditions, isolation, and purification makes this manipulation very interesting from an economic and environmental perspective.     

Role of Dimensionality for Photocatalytic Water Splitting: CdS Nanotube versus Bulk Structure

Using state-of-the-art density functional theoretical calculations, we have modelled a facetted CdS nanotube (NT) catalyst for photocatalytic water splitting. The overall photocatalytic activity of the CdS photocatalyst has been predicted based on the electronic structures, band edge alignment, and overpotential calculations. For comparisons, we have also investigated the water splitting process over bulk CdS. The band edge alignment along with the oxygen evolution reaction/hydrogen evolution reaction (OER/HER) mechanism studies help us find out the effective overpotential for the overall water splitting on these surfaces. Our study shows that the CdS NT has a highly stabilized valence band edge compared to that of bulk CdS owing to strong p–d mixing. The highly stabilized valence band edge is important for the hole-transfer process and reduces the risk of electron-hole recombination. CdS nanotube requires less overpotential for water oxidation reaction than the bulk CdS. Our findings suggest that the efficiency of the water oxidation/reduction process further improves in CdS as we reduce its dimensionality, that is going from bulk CdS to one-dimensional nanotube. Furthermore, the stabilized valence band edge of CdS nanotube also improves the photostability of CdS, which is a problem for bulk CdS.     

Magnetic field induced changes in linear and nonlinear optical properties of Ti incorporated Cr2O3 nanostructured thin film

We report the magnetic field effect on the linear and nonlinear optical properties of pulse laser ablated Ti-incorporated Cr₂O₃ nanostructured thin film. Optical properties have been experimentally analyzed under Voigt geometry by performing ultraviolet-visible spectroscopy and closed aperture Z-scan technique using a continuous wave He–Ne laser source. Nonlinear optical response reveals a single peak-valley feature in the far field diffraction pattern in absence of magnetic field ($\mathrm{B}=0$) confirming self-defocussing effect. This feature switches to a valley-peak configuration for $\mathrm{B}=5000\text{G}$, suggesting self-focusing effect. For $\mathrm{B}\le 750\text{G}$, oscillations were observed revealing the occurrence of higher order nonlinearity. Origin of nonlinearity is attributed to the near resonant d-d transitions observed from the broad peak occurring around 2 eV. These transitions are of magnetic origin and get modified under the application of external magnetic field. Our results suggest that magnetic field can be used as an effective tool to monitor the sign of optical nonlinearity and hence the thermal expansion in Ti-incorporated Cr₂O₃ nanostructured thin film.     

Study of ion transport and materials properties of K+-ion conducting solid polymer electrolyte (SPE): [(1-x) PEO: xCH3COOK]

Study of ion transport behavior in K⁺-ion conducting solid polymer electrolyte (SPE) films: [(1-x) PEO: xCH₃COOK] has been reported. Poly (ethylene oxide) PEO has been used as polymeric host and potassium acetate: CH₃COOK as complexing salt. SPE films in varying salt concentrations have been prepared by hot-press cast method. SPE film: [95PEO: 5CH₃COOK] has been identified as Optimum Conducting Composition (OCC) with room temperature conductivity (σ _rt) ~ 2.74 × 10⁻⁷ S/cm. As a consequence of salt complexation in polymeric host, σ _rt-enhancement of approximately two orders of magnitude was achieved in SPE OCC film. Ion transport property has been characterized in terms of ionic conductivity (σ), total ionic (t _ion)/cation (t ₊) transference numbers using different ac/dc techniques. Temperature-dependent conductivity measurement was done to explain mechanism of ion transport and to evaluate activation energy (E _a). XRD, FTIR, and DSC techniques were used to study materials property in SPE OCC film which also confirmed the complexation of salt in the polymeric host as well as increase in degree of amorphousity.

     

Aliskiren Hemifumarate Proliposomes for Improved Oral Drug Delivery: Formulation Development,In Vitro and In Vivo Permeability Testing

The objective of this study was to develop proliposomal formulations for a poorly bioavailable drug, aliskiren hemifumarate (AKH). A solvent evaporation method was used to prepare proliposomes using different lipids. The lipids of selection were soy phosphatidylcholine (SPC), dimyristoylphosphatidylcholine (DMPC), and dimyristoylphosphatidylglycerol sodium (DMPG Na), stearylamine, and cholesterol in various ratios. Proliposomes were evaluated for particle size, zeta potential, in vitro drug release, in vitro permeability, and in vivo pharmacokinetics upon hydration with aqueous phase. In vitro drug release studies were conducted in 0.01 N hydrochloric acid using USP type II dissolution apparatus. Parallel artificial membrane permeation assay (PAMPA) and Caco-2 cell line models were used to study the in vitro drug permeation. Male Sprague-Dawley (SD) rats were used to conduct in vivo pharmacokinetic studies. Among different formulations, proliposomes with drug/DMPC/cholesterol/stearylamine in the ratio of 1:5:0.025:0.050 (w/w/w/w) demonstrated the desired particle size, higher zeta potential, and higher encapsulation efficiency. The PAMPA and Caco-2 cell line experiments showed a significantly higher permeability of AKH with proliposomes as compared to pure AKH. In animal studies, the optimized formulation of proliposomes showed significant improvement in the rate and extent of absorption of AKH. Specifically, following a single oral administration, the relative bioavailability of AKH proliposome formulation was 230% when compared to pure AKH suspension.