The Eta-prime and Cooling with Staggered Fermions

We present a calculation of the mass of the eta-prime meson using quenched and dynamical staggered fermions. We also discuss the effects of "cooling" and suggest its use as a quantitative tool.Comment: 4 pages, LaTeX with 7 EPS figs, contribution to Lattice 9

Electronics and Chemistry: Varying Single Molecule Junction Conductance Using Chemical Substituents

We measure the low bias conductance of a series of substituted benzene diamine molecules while breaking a gold point contact in a solution of the molecules. Transport through these substituted benzenes is by means of nonresonant tunneling or superexchange, with the molecular junction conductance depending on the alignment of the metal Fermi level to the closest molecular level. Electron-donating substituents, which drive the occupied molecular orbitals up, increase the junction conductance, while electron-withdrawing substituents have the opposite effect. Thus for the measured series, conductance varies inversely with the calculated ionization potential of the molecules. These results reveal that the occupied states are closest to the gold Fermi energy, indicating that the tunneling transport through these molecules is analogous to hole tunneling through an insulating film.Comment: 14 pages, 4 figure

Enhanced Two-Photon Absorption in a Hollow-Core Photonic Bandgap Fiber

We show that two-photon absorption (TPA) in Rubidium atoms can be greatly enhanced by the use of a hollow-core photonic bandgap fiber. We investigate off-resonant, degenerate Doppler-free TPA on the 5S1/2 - 5D5/2 transition and observe 1% absorption of a pump beam with a total power of only 1 mW in the fiber. These results are verified by measuring the amount of emitted blue fluorescence and are consistent with the theoretical predictions which indicate that transit time effects play an important role in determining the two-photon absorption cross-section in a confined geometry.Comment: 5 pages, 6 figure

Effect of Manasamitra vatakam, an Ayurvedic Formulation, on Aluminium-Induced Neurotoxicity in Rats

Purpose: To investigate the effect of Manasamitra vatakam (MMV), an Ayurvedic formulation, on aluminium (Al)-induced neurotoxicity in rats.Methods: Wistar rats were selected for the present study and were divided into four groups of six animals each. Group I (control) received tap water while group II received aluminium chloride (AlCl3, 100 mg/kg/day). Group III was treated with concurrently Al chloride (100 mg/kg/day) and MMV drug (100 mg/kg /day). Group IV were administered MMV (100 mg/kg/day) for 90 days. Behavioral tests were performed on the rats during the experiment. At the end of the experiment various biochemical,neurochemical and histopathological histopathological was assessments were also carried out on the blood and brain of the rats.Results: Following MMV treatment, there was a significant recovery in the performance of the radial maze and muscle grip strength of the rats, as well as the levels of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and acetylcholinestrase (AChE) in different parts of the rat’s brain. The neuroprotective efficacy of MMV was supported by histopathological observations. Furthermore, MMV afforded protection against oxidative damage in the rats.Conclusion: MMV prevents Al-induced toxicity in peripheral as well as in central nervous systems of rats. Therefore, further studies are required to ascertain its usefulness in humans.Keywords: Rat brain, Aluminium chloride, Behavioral studies, Neurotoxicity, Manasamitra vatakam

Formation and Evolution of Single Molecule Junctions

We analyze the formation and evolution statistics of single molecule junctions bonded to gold electrodes using amine, methyl sulfide and dimethyl phosphine link groups by measuring conductance as a function of junction elongation. For each link, maximum elongation and formation probability increase with molecular length, strongly suggesting that processes other than just metal-molecule bond breakage play a key role in junction evolution under stress. Density functional theory calculations of adiabatic trajectories show sequences of atomic-scale changes in junction structure, including shifts in attachment point, that account for the long conductance plateau lengths observed.Comment: 10 pages, 4 figures, submitte

Functionalization of the internal surfaces of layered cadmium thiophosphate with cationic surfactants: adsolubilization of uncharged organic molecules

Ion-exchange intercalation of the cationic surfactant cetyl trimethylammonium in layered CdPS3 leads to the formation of an intercalated bilayer within the galleries, thereby converting the internal surface of the layers from hydrophilic to hydrophobic. Several uncharged organic 'guest' molecules were found to be solubilized in the intercalated bilayer 'host'