Synthesis,antibacterial, anticancer and molecular docking studies of macrocyclic metal complexes of dihydrazide and diketone

The complexes of Co(II), Ni(II), Cu(II) and Zn(II) metal ions has been synthesized through template method by the condensation of succinic acid dihydrazide with 5-chloroisatin in alcoholic medium. Complexes were characterized by C H N analysis, molar conductance, thermal analysis, magnetic susceptibility, mass spectrometry, FTIR, EPR, ¹H NMR, UV–Visible spectroscopy. These studies suggest an octahedral geometry for all the complexes. The compounds were found active against B. subtilis and S. aureus and P. aeruginosa and E. coli bacteria. The Zn(II) complex showed significant anticancer activity against Squamous Cell Carcinoma cells tested by the MTT assay method. Molecular docking studies with EGFR tyrosine kinase were also carried out. All these results show that some of the synthesized compounds have remarkable antibacterial and anticancer property.     

Unsteady peristaltic transport of Maxwell fluid through finite length tube: application to oesophageal swallowing

This paper analytically investigates the unsteady peristaltic transport of the Maxwell fluid in a finite tube.The walls of the tube are subjected to the contraction waves that do not cross the stationa...     

A new flavanone, reflexin, from Cuscuta reflexa and its selective sensing of nitric oxide

A new compound, reflexin, 5-hydroxy-7-methoxy-6-(2,3-epoxy-3-methylbutyl)-flavanone, is isolated from the stems of Cuscuta reflexa along with three other known compounds. This new compound has good potential for application especially in the photoactivity of reflexin. It was found to be sensitive to glutathione, forming a fluorescent product that is utilized for sensing nitric oxide (NO). The lowest detection limit of NO analysis was found to be 0.05 μM.     

Explosive instability in a backward wave oscillator

A plasma filled backward wave oscillator supports Trivelpiece-Gould (TG) and TM modes. The former can be driven unstable by a relativistic electron beam via Cerenkov interaction or by the plasma return current as two stream instability. This unstable TG mode can parametrically couple to a TM mode via a negative energy beam mode giving rise to an explosive instability     

Hot carrier diffusion induced instabilities of electromagnetic waves in plasmas and semiconductors

The stability of a plasma/semiconductor for small fluctuations in the intensity of plane electromagnetic beam has been studied when a non-linearity in the dielectric constant appears on account of the diffusion of non-uniformly heated carriers (due to fluctuations in the intensity of the beam). Fluctuations of optimum size and long duration have been found to grow at moderate powers. The effect of absorption is, however, to suppress this effect.Work supported by CSIR (India) and NSF (USA)     

Self-focusing of a laser beam in a strongly ionized plasma

In the presence of a strong Gaussian laser beam, the non-linearity in the dielectric constant of a strongly ionized plasma has been investigated. The non-linearity arises due to the heating and redistribution of the electrons; the loss of electron energy gained from the field has been assumed to be due to thermal conduction. This self-induced non-linearity causes a self-focusing and oscillatory waveguide propagation of the beam even when the non-linear dielectric constant does not fall in the saturating range. In a typical case of a 10¹⁰ W laser, the enhancement of axial intensity by a factor of 25 has been predicted in a length of 0.6 cm.Works supported by N.S.F. (USA).On leave from Malviya Regional Engeeniring College, Jaipur-4, India.     

Bloch enhancement of electric field gradient in Fe and Cu host alloys

The Bloch enhancement factor α(k _f ) of the electric field gradient has been evaluated for the half-filledd-core Fe host metal and completely filledd-core Cu host metal in single orthogonalized plane wave (OPW) approximation. For this purpose the radially-dependent antishielding factors,γ(r) have been calculated in non-orthogonal Hartree-Fock perturbation theory (NHFPT). The results show that the contributions of antishielding to α(k _f ) from the plane wave-plane wave part and the core part of the OPW state are individually large but opposite in sign and thereby lead to partial cancellation. The net effect of antishielding on α(k _f ) is found to be − 5.6% in Fe and 14% in Cu.     

The influence of transverse magnetic field on Gunn effect threshold

The effect of magnetic field has been studied on the Gunn effect threshold electric field for short planar Gunn devices. For low magnetic fields, experimental results are in good agreement with the theoretical results but a large increase in threshold electric field has been observed for higher magnetic fields.     

Anderson-Grüneisen parameter δ for ionic crystals - a clarification

The equations describing the interaction of optical pulses with three-level resonant media are considered. It is shown that the resonant medium, if excited by suitable sequences of ultrashort optical pulses, can generate up-converted or down-converted photon echoes.     

Isotope exchange of iodine in iodide-iodate melts studied by radio paper chromatography

The isotopic exchange reaction of iodine in fused NaI–NaIO₃ and KI–KIO₃ systems, which does not proceed until the mixture is melted, is found to be almost instantaneous in homogeneous melts. The equilibrium is attained within a period of less than 5 min at a temperature 5°C above the melting temperature of each composition for both systems. No noticeable exchange is observed even after heating the samples for 30 min at a temperature 20°C below the corresponding melting point. A single-step bimolecular association-dissociation mechanism is proposed for the exchange.