Yb:YAG and Nd:YAG edge-pumped slab lasers

Experimental demonstrations of two edge-pumped zigzag slab lasers are presented. The Nd:YAG slab laser generated 127 W of multimode output power with 300W of pump power. Preliminary results with a Yb:YAG slab produced 46 W of output power with 315W of pump power. The edge-pumped slab design permits symmetric conduction cooling and efficient pump absorption and accepts large-numerical-aperture pump sources.     

Defibrillation via the elimination of spiral turbulence in a model for ventricular fibrillation

Ventricular fibrillation, the major reason behind sudden cardiac death, is turbulent cardiac electrical activity in which rapid, irregular disturbances in the spatiotemporal electrical activation of the heart make it incapable of any concerted pumping action. Methods of controlling ventricular fibrillation include electrical defibrillation as well as injected medication. Electrical defibrillation, though widely used, involves subjecting the whole heart to massive, and often counterproductive, electrical shocks. We propose a defibrillation method that uses a very low-amplitude shock (of order mV) applied for a brief duration (of order 100 ms) and over a coarse mesh of lines on our model ventricle.     

Genetic Algorithms for Design of Discrete Phase-only Reconfigurable Array Antennas with Fixed Dynamic Range Ratio

In this paper, we present a new method based on real-coded Genetic Algorithm (GA) with elitist model for optimal design of a reconfigurable symmetrical dual-beam uniformly spaced linear isotropic antenna array with phase-only control of quantized phase shifters. The problem is to find a common amplitude distribution that will generate a pencil beam with zero phases and a flat-top beam with discrete phases of a six-bit discrete phase shifter, without or with pre-fixing the value of dynamic range ratio (|I _max/I _min|) of excitation current amplitude distribution equal to or less than five.     

Copper(II) complexes of thioarylazo-pentanedione: Structures,magnetism, redox properties and correlation with DFT calculations

Copper(II) complexes of 3-((2-(alkylthio)phenylazo)-2,4-pentanedione, tridentate O, N, S donor ligands, are described in this work. Chloride bridged copper(II) polymers (1) and thiocyanato bridged copper(II) dimmers (2) are characterized by a single crystal X-ray diffraction study. The complexes show antiferromagnetic interactions, with J = −0.5 ± 0.1 cm⁻¹ (1a) and −25.8 ± 0.5 cm⁻¹ (2b), which implies stronger coupling in the –SCN-bridging compound. The spectra, redox and magnetism are explained by DFT studies.     

Interplay between hydration and electrostatic attraction in ligand binding: direct observation of hydration barrier at reverse micellar interface

The recognition of a charged biomolecular surface by an oppositely charged ligand is governed by electrostatic attraction and surface hydration. In the present study, the interplay between electrostatic attraction and hydration at the interface of a negatively charged reverse micelle (RM) at different temperatures has been addressed. Temperature-dependent solvation dynamics of a probe H33258 (H258) at the reverse micellar interface explores the nature of hydration at the interface. Up to 45 degrees C, the environmental dynamics reported by the interface-binding probe H258 becomes progressively faster with increasing temperature and follows the Arrhenius model. Above 45 degrees C, the observed dynamics slows down with increasing temperature, thus deviating from the Arrhenius model. The slower dynamics at higher temperatures is interpreted to be due to increasing contributions from the motions of the surfactant head groups, indicating the proximity of the probe to the interface at higher temperatures. This suggests an increased electrostatic attraction between the ligand and interface at higher temperatures and is attributed to the change in hydration. Densimetric and acoustic studies, indeed, show a drastic increase in the apparent specific adiabatic compressibility of the water molecules present in RMs after 45 degrees C, revealing the existence of a softer hydration shell at higher temperatures. Our study indicates that the hydration layer at a charged interface acts both as physical and energetic barrier to electrostatic interactions of small ligands at the interface.     

Thickness of the hydration layer of a protein from molecular dynamics simulation

Water molecules around a protein exhibit slow dynamics with respect to that of pure bulk water. One important issue in protein hydration is the thickness of the hydration layer (i.e., the distance from the protein surface up to which the water dynamics is influenced by the protein). Estimation of thickness is crucial to understand better the properties of "biological water" and the role that it plays in guiding the protein's function. We have performed an atomistic molecular dynamics simulation of an aqueous solution of the protein villin headpiece subdomain or HP-36 to estimate the thickness of its hydration water. In particular, several dynamical properties of water around different segments (three alpha-helices) of the protein have been calculated by varying the thickness of the hydration layers. It is found that in general the influence of the helices on water properties extends beyond the first hydration layer. However, the heterogeneous nature of water among the first hydration layers of the three helices diminishes as the thickness is increased. It indicates that, for a small protein such as HP-36, the thickness of "biological water" is uniform for different segments of the protein.     

An electron in the field of phonons and magnons

The behaviour of a conduction electron in the presence of two Bose fields, namely, phonons and magnons in ferromagnetic semiconductors is studied. The effects of both electron-magnon and electron-phonon interactions on the energy renormalization are calculated.     

Shape evolution in odd-A 137 Pm

The odd mass nucleus ¹³⁷Pm has been studied to high spins through the ¹⁰⁹Ag(³²S, 2p2n)¹³⁷Pm reaction at an incident beam energy of 150 MeV. The de-exciting ??-rays were detected using an array of 18 Compton suppressed clover detectors. The level scheme of ¹³⁷Pm has been extended up to $J^\pi = \tfrac{{43}} {2}^ -$ and excitation energy of E _x ? 6 MeV with the observation of 42 new gamma transitions. The linear polarization (IPDCO) measurements for the ??-ray transitions have been done for the first time. The spin and parity assignments for most of the reported levels have been made using these results and the coincidence angular anisotropy (R_DCO) measurements. The nuclear shape evolution is discussed in the light of Total Routhian Surface (TRS) and Cranked Shell Model (CSM) calculations.     

Letter: Behavior of Magnetic Tubes in Neutron Star's Interior

It is found from Maxwell's equations that the magnetic field lines are good analogues of relativistic strings. It is shown that the superconducting current in the neutron star's interior causes local rotation of magnetic flux tubes carrying quantized flux.