Design of MMICs employing whispering-gallery mode dielectric resonators at microwave and millimeter wave frequencies

A simple theoretical model for predicting the resonant frequencies of the modes of the whispering — gallery (WG) mode dielectric resonators MICs (Microwave Integrated Circuits) at microwave and millimetre wave frequencies is presented. The unsymmetric field distribution for WGE mode in the axial direction is taken into account. The theoretical results are found to be in good agreement with the practical results taken at microwaves C-X bands. In addition, the variation of resonant modes against dielectric resonator's dimensions and dielectric constant is modelled. The effect of the width of dielectric substrate on resonant modes is also illustrated.     

Isolation and structure of a new alkaloid from rauwolfia serpentina benth

A new dihydroindole alkaloid sandwicolidine has been isolated from Rauwolfia serpentina and its structure elucidated through chemical and spectroscopic studies.     

Effect of RuO2 in the shape selectivity of submicron-sized SnO2 structures

Several dissimilar types of tin oxide microstructures including bipyramids, cubes, and wires synthesized effectively by means of a simple approach were investigated using X-ray diffraction (XRD), thermogravimetry/differential thermometric analysis (TG-DTA), and X-ray photoelectron spectroscopy (XPS). A possible growth mechanism is proposed using the results of these studies. The texture coefficient values of all the structures, indexed to a tetragonal lattice, exhibit amazing variation in the preferred orientation with respect to their shapes. Although XPS data indicate that wires and cubes have a strong SnO(2) type signal, bipyramids interestingly exhibit both SnO and SnO(2) signals and a correlation of the binding energy helps in understanding the growth kinetics of such submicron structures. The results suggest that the bipyramids are formed because of the vapor-solid process (VS) while wires and cubes are formed by the vapor-liquid-solid (VLS) progression.     

Fabrication and Biological Assessment of Antidiabetic α-Mangostin Loaded Nanosponges: In Vitro,In Vivo,and In Silico Studies

Type 2 diabetes mellitus has been a major health issue with increasing morbidity and mortality due to macrovascular and microvascular complications. The urgent need for improved methods to control hyperglycemic complications reiterates the development of innovative preventive and therapeutic treatment strategies. In this perspective, xanthone compounds in the pericarp of the mangosteen fruit, especially α-mangostin (MGN), have been recognized to restore damaged pancreatic β-cells for optimal insulin release. Therefore, taking advantage of the robust use of nanotechnology for targeted drug delivery, we herein report the preparation of MGN loaded nanosponges for anti-diabetic therapeutic applications. The nanosponges were prepared by quasi-emulsion solvent evaporation method. Physico-chemical characterization of formulated nanosponges with satisfactory outcomes was performed with Fourier transform infra-red (FTIR) spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Zeta potential, hydrodynamic diameter, entrapment efficiency, drug release properties, and stability studies at stress conditions were also tested. Molecular docking analysis revealed significant interactions of α-glucosidase and MGN in a protein-ligand complex. The maximum inhibition by nanosponges against α-glucosidase was observed to be 0.9352 ± 0.0856 µM, 3.11-fold higher than acarbose. In vivo studies were conducted on diabetic rats and plasma glucose levels were estimated by HPLC. Collectively, our findings suggest that MGN-loaded nanosponges may be beneficial in the treatment of diabetes since they prolong the antidiabetic response in plasma and improve patient compliance by slowly releasing MGN and requiring less frequent doses, respectively.     

Synthesizing PET and food waste into refuse plastic fuel (RPF): optimization and kinetic modeling

Journal of Thermal Analysis and Calorimetry - With rapid urbanization and industrialization, cheap energy supply from fossil fuels has become a problem of great extent, due to the rising fuel...     

Insight into the magnetic behavior of Sr2IrO4: A spontaneous magnetization study

Sr₂IrO₄ is a weak ferromagnet where the spin arrangement is canted anti-ferromagnetic (AF). Moreover, the spin-structure coupling plays an important role in magnetic behavior of Sr₂IrO₄. In this concern the magnetization under zero applied field i.e. spontaneous magnetization would be interesting to study and would give insight into the novel magnetic behavior of Sr₂IrO₄. Sophisticated techniques like neutron diffraction, μSR etc has been used to understand the magnetic behavior of Sr₂IrO₄ under zero applied field. To understand the magnetic behavior we have performed field and temperature dependent magnetization study. The measured field and temperature dependent magnetic data is analyzed rigorously. We have attempted to understand the temperature dependance of spontaneous magnetization, remanent magnetization and coercive force. We observe that the spontaneous magnetization extracted from Arrott plot shows that the Sr₂IrO₄ is not an ideal ferromagnet. The temperature dependent coercive field follows Guant's model of strong domain wall pinning. Our investigation explicit the temperature dependence of various magnetic properties shows the magnetic transitions from paramagnetic to ferromagnetic phase with $T_c$ around 225 K and a low temperature evolution of magnetic moment around $T_M～90$ K.     

High-Speed Cylindrical Collapse of Type-I Matter

In this paper, the cylindrical symmetric gravitational collapse with anisotropic pressure has been investigated using high-speed approximation scheme. The collapsing speed of the fluid is assumed to be very large. To see the effects of pressure, we have used the equations $ \sqrt{p_{R}/\rho}=k$ and $\sqrt{p_{T}/\rho}=w$ of states for radial pressure and tangential pressure, respectively. It is observed that if the ratios of both pressures, that is, tangential and radial pressures, to energy density are bounded from below by some positive value, there arise two possibilities depending on whether 1?+?k ²???2 w ²?>?0 or 1?+?k ²???2w ²?<?0. For 1?+?k ²???2 w ²?>?0, the high-speed approximation scheme fails, while for 1?+?k ²???2 w ²?<?0, the high-speed approximation works. For vanishing w and k, the high-speed scheme does not break down, and, as a result, a naked singularity forms in this case. For p _T ?=?p _R ?=?p, all the results reduce to the perfect fluid case obtained by Nakao and Morisawa (Prog Theor Phys 113:73, 2005).     

Reclamation of Used Engine Oil

Used lubricating oil from vehicles was treated with various types of chemicals to be regenerated. It was found that used lubricating oil could be reclaimed with sulphuric acid, sodium hydroxide, sodium phosphate, ammonium sulphate and rosin. Viscosity and pour point of the reclaimed lubricating oil were improved with the additive methyl methacrylate. The reclaimed lubricating oil was characterized by four‐ball ma chine and it was found that wear scar diameter (WSD) has greatly been de creased with the reclamation. The results of atomic absorption spectrophotometer also show that wear metals have also been de creased to an appreciable amount in there claimed lubricating oil.     

Crystallographic report: Bis[3‐(tri‐p‐tolyl)germyl‐3‐(o‐tolyl)‐propionato]dibutyltin(IV)

The crystal structure of [(p‐CH₃C₆H₄)₃GeCH(o‐CH₃C₆H₄)CH₂CO₂]₂Sn(C₄H₉)₂ consists of a monomer with the atoms of tin and germanium both occupying tetrahedral geometries. However, the tin atom is distorted towards a skew trapezoidal bipyramid geometry as a result of weakly chelating carboxylate ligands. Copyright © 2003 John Wiley & Sons, Ltd.     

One-pot access to a privileged library of six membered nitrogenous heterocycles through multi-component cascade approach

The presence of heterocycles and heteroaromatics as ubiquitous components in a diverse variety of synthetic drugs, biologically active molecules, and natural products has inspired the researchers to develop new strategies and technologies for their easy accessibility. Among them, six membered nitrogenous heterocycles gained immense interest, and significant efforts have been made to the development of synthetic strategies which could lead to the discovery of architecturally complex and diverse molecules with high efficiency, low cost, less organic waste and shorter reaction time. Access to such systems by one-pot multi-component approach with inherent advantages of step-economy, operational simplicity, synthetic efficiency, and environmental compatibility is particularly attractive. The current review article highlights the recent developments in the synthesis of six membered nitrogen-containing heterocyclic scaffolds through one-pot multi-component assembly approach.