Partial molar adiabatic compressibilities of transfer of some amino acids from water to aqueous lactose solutions at different temperatures

Apparent molar adiabatic compressibilities (K_{?, s}) of glycine, L-alanine, L-valine, and L-leucine have been determined in aqueous and mixed aqueous solutions of lactose (2 to 6 mass%) at T = (293.15, 298.15, 303.15, and 308.15) K. From these data partial molar adiabatic compressibilities at infinite dilution (K_{?, s}⁰) have been evaluated to calculate corresponding transfer function. The transfer partial molar adiabatic compressibilities at infinite dilution (ΔK_{?, s}⁰) are found to be positive. The decrease in the magnitude of transfer partial molar adiabatic compressibilities from glycine to L-leucine indicates the dominance of hydrophobic-hydrophobic interactions between the increasing side chains of amino acids. Also, the contributions of NH₃⁺COO⁻ , and CH₂ groups have been calculated by the linear correlation of K_{?, s}⁰ with number of carbon atoms in the alkyl chain of amino acids.     

Electron Acceleration by Beating of Two Intense Cross-Focused Hollow Gaussian Laser Beams in Plasma

This paper presents propagation of two cross-focused intense hollow Gaussian laser beams(HGBs) in collisionless plasma and its effect on the generation of electron plasma wave(EPW) and electron acceleration process,when relativistic and ponderomotive nonlinearities are simultaneously operative. Nonlinear differential equations have been set up for beamwidth of laser beams, power of generated EPW, and energy gain by electrons using WKB and paraxial approximations. Numerical simulations have been carried out to investigate the effect of typical laser-plasma parameters on the focusing of laser beams in plasmas and further its effect on power of excited EPW and acceleration of electrons. It is observed that focusing of two laser beams in plasma increases for higher order of hollow Gaussian beams,which significantly enhanced the power of generated EPW and energy gain. The amplitude of EPW and energy gain by electrons is found to enhance with an increase in the intensity of laser beams and plasma density. This study will be useful to plasma beat wave accelerator and in other applications requiring multiple laser beams.     

Effect of ion velocity on SHI-induced mixing in Ti/Bi system

Energetic ion beams are proving to be versatile tools for modification and depth profiling of materials. The energy and ion species are the deciding factor in the ion-beam-induced materials modification. Among the various parameters such as electronic energy loss, fluence and heat of mixing, velocity of the ions used for irradiation plays an important role in mixing at the interface. The present study is carried out to find the effect of the velocity of swift heavy ions on interface mixing of a Ti/Bi bilayer system. Ti/Bi/C was deposited on Si substrate at room temperature by an electron gun in a high-vacuum deposition system. Carbon layer is deposited on top to avoid oxidation of the samples. Eighty mega electron volts Au ions and 100?MeV Ag ions with same value of S_e for Ti are used for the irradiation of samples at the fluences 1?×?10¹³–1?×?10¹⁴ ions/cm². Different techniques like Rutherford backscattering spectroscopy, atomic force microscopy and grazing incidence X-ray diffraction were used to characterize the pristine and irradiated samples. The mixing effect is explained in the framework of the thermal spike model. It has been found that the mixing rate is higher for low-velocity Au ions in comparison to high-velocity Ag ions. The result could be explained as due to less energy deposition in thermal spike by high-velocity ions.     

Effect of NaClO4 concentration on electrolytic behaviour of corn starch film for supercapacitor application

Polymer electrolyte has seen tremendous growth after works of Fenton & Armand, and energy devices are being produced at commercial level. Today’s social lifestyle needs miniaturized energy devices at every step of life; consequently, they add up to chemical garbage of the world. The sustainable development in the field needs eco-friendly energy devices. Hence, starch (being at low cost, abundant in nature and eco-friendly) has received great scientific attention. In recent past, many attempts have been made to modify the various starches to get fast ion-conducting materials. In our laboratory, also, wheat, potato, rice and arrowroot starches have been modified with different sodium salts, and in each case, considerably high-conducting (>10⁻³ S/cm) films have been found. In present case, also, a high-conducting transparent film (10⁻² S/cm) is obtained with corn starch and NaClO₄ salt after being crosslinked with glutaraldehyde (GA). Bode plots (both phase and magnitude), capacitive-response plot, capacitive-frequency plots and linear sweep voltammetry curves are analysed to explain the possibility of using the prepared electrolyte in capacitive device. The larger electrochemical stability window (ESW) ~ 2.4 V and smaller ion relaxation time ~ 65 μs make it a potential candidate for device fabrication. The equivalent series resistance is ~6.252 Ω for 0.8-mm-thick sample.

     

Small angle neutron scattering study of doxorubicin-surfactant complexes encapsulated in block copolymer micelles

Self-assembling behaviour of block copolymers and their ability to evade the immune system through polyethylene oxide stealth makes it an attractive candidate for drug encapsulation. Micelles formed by polyethylene oxide-polypropylene oxide- polyethylene oxide triblock copolymers (PEO-PPO-PEO), pluronic P123, have been employed for encapsulating the anti-cancer drug doxorubicin hydrochloride. The binding affinity of doxorubicin within the micelle carrier is enhanced through complex formation of drug and anionic surfactant, aerosol OT (AOT). Electrostatic binding of doxorubicin with negatively charged surfactants leads to the formation of hydrophobic drug-surfactant complexes. Surfactant-induced partitioning of the anti-cancer drug into nonpolar solvents such as chloroform is investigated. SANS measurements were performed on pluronic P123 micelles in the presence of drug-surfactant complex. No significant changes in the structure of the micelles are observed upon drug encapsulation. This demonstrates that surfactant- drug complexes can be encapsulated in block copolymer micelles without disrupting the structure of aggregates.      

Synthesis,spectroscopic evaluation,molecular modelling,thermal study and biological evaluation of manganese(II) complexes derived from bidentate N,O and N,S donor Schiff base ligands

Manganese(II) complexes having the general composition Mn(L)₂X₂ (where L = 3‐bromoacetophenone semicarbazone, 3‐bromoacetophenone thiosemicarbazone, 1‐tetralone semicarbazone, 1‐tetralone thiosemicarbazone, flavanone semicarbazone or flavanone thiosemicarbazone and X = Cl^? or ½SO₄^2?) were synthesized. All the complexes were characterized using elemental analyses, molar conductance and magnetic moment measurements, and mass, ¹H NMR, infrared, electron paramagnetic resonance and electronic spectral studies. The molar conductance of the complexes in dimethylsulfoxide lies in the range 10–20 Ω^?1 cm² mol^?1 indicating their non‐electrolytic nature. All the complexes show magnetic moments corresponding to five unpaired electrons. The possible geometries of the complexes were assigned on the basis of electron paramagnetic resonance, electronic and infrared spectral studies. Some of the synthesized ligands and their complexes were screened for their antifungal activities against fungi Macrophomina phaseolina, Botrytis cinerea and Phoma glomerata using the food poison technique and their antibacterial activities against Xanthomonas campestris pv. campestris and Ralstonia solanacearum using the paper disc diffusion method. They showed appreciable activities.     

N‐Heterocyclic Carbene Catalysis via Azolium Dienolates: An Efficient Strategy for Remote Enantioselective Functionalizations

N‐heterocyclic carbene (NHC) catalysis has emerged as a powerful strategy in organic synthesis. In recent years a number of reviews have been published on NHC‐catalyzed transformations involving Breslow intermediates, acyl azoliums, α,β‐unsaturated acyl azoliums, homoenolate equivalents, and azolium enolates. However, the azolium dienolate intermediates generated by NHCs have been employed in asymmetric synthesis only very recently, especially in cycloadditions dealing with remote functionalization. This Minireview highlights all the developments and the new advances in NHC‐catalyzed asymmetric cycloaddition reactions involving azolium dienolate intermediates.     

tert-Butyl nitrite induced radical dimerization of primary thioamides and selenoamides at room temperature

A simple and efficient method for the dimerization of primary thioamides into 1,2,4-thiadiazoles using tert-butyl nitrite is described. The optimized condition was also found to be suitable for the dimerization of benzoselenoamides into 1,2,4-selenadiazoles. All the reactions proceed smoothly at room temperature and gave the desired products in excellent yields in a short span of time.