Gender and Rapid Alterations of Hemispheric Dominance during Planning

Background: Mental planning and carrying out a plan provoke specific cerebral hemodynamic responses. Gender aspects of hemispheric laterality using rapid cerebral hemodynamics have not been reported. Method: Here, we applied functional transcranial Doppler sonography to examine lateralization of cerebral hemodynamics of the middle cerebral arteries of 28 subjects (14 women and 14 men) performing a standard planning task. There were easy and difficult problems, and mental planning without motor activity was separated from movement execution. Results: Difficult mental planning elicited lateralization to the right hemisphere after 2 or more seconds, a feature that was not observed during movement execution. In females, there was a dominance to the left hemisphere during movement execution. Optimized problem solving yielded an increased laterality change to the right during mental planning. Conclusions: Gender-related hemispheric dominance appears to be condition-dependent, and change of laterality to the right may play a role in optimized performance. Results are of relevance when considering laterality from a perspective of performance enhancement of higher cognitive functions, and also of psychiatric disorders with cognitive dysfunctions and abnormal lateralization patterns such as schizophrenia. Copyright (C) 2012 S. Karger AG, Base

Temperature and Dissolved Oxygen Simulations for a Lake with Ice Cover

To project the effect of potential climate change on water quality and ecology of lakes in a region, deterministic simulation models for water temperature and for dissolved oxygen concentration have been developed by Stefan, Hondzo and Fang (1993). The water temperature model is driven by meteorological parameters which act on a lake through the water surface (Fig. 1). In cold regions where lakes are icecovered in winter, heat and oxygen transfer processes, which normally occur through an open water surface, are substantially altered by winter ice and snow cover. Therefore separate models for winter conditions must be developed. The objective of this report is to describe the development of process-oriented deterministic, onedimensional winter water temperature and dissolved oxygen models which predict the water quality in a lake from fall through the ice-cover period and into spring. Starting with conditions typical of the end of the open water season, the winter water temperature model must include simulation of cooling of the surface water to freezing conditions, latent heat removal, onset of ice-cover, radiation and conduction heat transfer through ice and snow and water mixing below the ice cover. One of the applications of these models will be to study the effect of low water temperatures and oxygen levels on fish survival and growth in ice-covered lakes under different climate conditions.Environmental Research Laboratory, US Environmental Protection Agenc

A new purge and trap headspace technique to analyze low volatile compounds from fluid inclusions of rocks and minerals

A new method for the analysis of trace gases from fluid inclusions of minerals has been developed. The purge and trap GC-MS system is based on the system described by Nolting et al. (1988) and was optimized for the analyses of halogenated volatile organic compounds (VOCs) having boiling points as low as -128. °C (carbon tetrafluoride).The sample preconcentration cold trap consists of a U-shaped glass lined steel tube (GLT™), that is immersed into a small liquid nitrogen Dewar vessel for cooling. A rapid desorption step heats up the preconcentration tube in <30s from -196°C to 200°C. The process is carried out by using a pressurized air stream to dissipate the liquid nitrogen followed by resistive heating of the trap. The design of the cold trap and the direct transfer of desorbed analytes onto the GC column via a deactivated capillary column retention gap made sample refocusing within the GC oven unnecessary. Furthermore, a special air-tight grinding device was developed in which samples ranging from soft halite (hardness 2, Mohs scale) to hard quartz (hardness 7) are effectively ground to average diameters of 1000nm or below, thereby releasing gases from fluid inclusions of minerals. The gases are then purged from the grinding chamber with a He carrier gas flow. The detection and quantitative determination of gases, such as SF6 and CF4 released from fluorites and CH3Cl from halite samples is demonstrated.DFG/FOR/76

Entropy production by resonance decays

We investigate entropy production for an expanding system of particles and resonances with isospin symmetry -- in our case pions and $\rho$ mesons -- within the framework of relativistic kinetic theory. A cascade code to simulate the kinetic equations is developed and results for entropy production and particle spectra are presented.Comment: 17 pages, 10 ps-figures included, only change: preprint number adde

The Physical Model Study of the Fish Bypass Louver System of the School Street Hydroelectric Project

Kleinschmidt Associates and Reliant Energ

An integrated cryogenic optical modulator

Integrated electrical and photonic circuits (PIC) operating at cryogenic temperatures are fundamental building blocks required to achieve scalable quantum computing, and cryogenic computing technologies. Optical interconnects offer better performance and thermal insulation than electrical wires and are imperative for true quantum communication. Silicon PICs have matured for room temperature applications but their cryogenic performance is limited by the absence of efficient low temperature electro-optic (EO) modulation. While detectors and lasers perform better at low temperature, cryogenic optical switching remains an unsolved challenge. Here we demonstrate EO switching and modulation from room temperature down to 4 K by using the Pockels effect in integrated barium titanate (BaTiO3)-based devices. We report the nonlinear optical (NLO) properties of BaTiO3 in a temperature range which has previously not been explored, showing an effective Pockels coefficient of 200 pm/V at 4 K. We demonstrate the largest EO bandwidth (30 GHz) of any cryogenic switch to date, ultra-low-power tuning which is 10^9 times more efficient than thermal tuning, and high-speed data modulation at 20 Gbps. Our results demonstrate a missing component for cryogenic PICs. It removes major roadblocks for the realisation of novel cryogenic-compatible systems in the field of quantum computing and supercomputing, and for interfacing those systems with the real world at room-temperature

Two pore domain potassium channels in cerebral ischemia: a focus on K2P9.1 (TASK3, KCNK9)

BACKGROUND: Recently, members of the two-pore domain potassium channel family (K2P channels) could be shown to be involved in mechanisms contributing to neuronal damage after cerebral ischemia. K2P3.1-/- animals showed larger infarct volumes and a worse functional outcome following experimentally induced ischemic stroke. Here, we question the role of the closely related K2P channel K2P9.1. METHODS: We combine electrophysiological recordings in brain-slice preparations of wildtype and K2P9.1-/- mice with an in vivo model of cerebral ischemia (transient middle cerebral artery occlusion (tMCAO)) to depict a functional impact of K2P9.1 in stroke formation. RESULTS: Patch-clamp recordings reveal that currents mediated through K2P9.1 can be obtained in slice preparations of the dorsal lateral geniculate nucleus (dLGN) as a model of central nervous relay neurons. Current characteristics are indicative of K2P9.1 as they display an increase upon removal of extracellular divalent cations, an outward rectification and a reversal potential close to the potassium equilibrium potential. Lowering extracellular pH values from 7.35 to 6.0 showed comparable current reductions in neurons from wildtype and K2P9.1-/- mice (68.31 +/- 9.80% and 69.92 +/- 11.65%, respectively). These results could be translated in an in vivo model of cerebral ischemia where infarct volumes and functional outcomes showed a none significant tendency towards smaller infarct volumes in K2P9.1-/- animals compared to wildtype mice 24 hours after 60 min of tMCAO induction (60.50 +/- 17.31 mm3 and 47.10 +/- 19.26 mm3, respectively). CONCLUSIONS: Together with findings from earlier studies on K2P2.1-/- and K2P3.1-/- mice, the results of the present study on K2P9.1-/- mice indicate a differential contribution of K2P channel subtypes to the diverse and complex in vivo effects in rodent models of cerebral ischemia

Antihyperon-Production in Relativistic Heavy Ion Collision

Recently it has been shown that the observed antiproton yield in heavy-ion collisions at CERN-SpS energies can be understood by multi-pionic interactions which enforce local chemical equilibrium of the antiprotons with the nucleons and pions. Here we show that antihyperons are driven towards local chemical equilibrium with pions, nucleons and kaons on a timescale of less than 3 fm/c when applying a similar argument for the antihyperons by considering the inverse channel of annihilation reactions anti-Y + p to pions + kaons. These multi-mesonic reactions easily explain the antihyperon yields at CERN-SpS energies as advertised in pure thermal, hadronic models without the need of a quark gluon plasma phase. In addition, the argument also applies for AGS energies.Comment: 4 pages using RevTeX, 1 eps figur

Excitotoxic neuronal cell death during an oligodendrocyte-directed CD8+ T cell attack in the CNS gray matter

Background: Neural-antigen reactive cytotoxic CD8+ T cells contribute to neuronal dysfunction and degeneration in a variety of inflammatory CNS disorders. Facing excess numbers of target cells, CNS-invading CD8+ T cells cause neuronal cell death either via confined release of cytotoxic effector molecules towards neurons, or via spillover of cytotoxic effector molecules from 'leaky’ immunological synapses and non-confined release by CD8+ T cells themselves during serial and simultaneous killing of oligodendrocytes or astrocytes. Methods: Wild-type and T cell receptor transgenic CD8+ T cells were stimulated in vitro, their activation status was assessed by flow cytometry, and supernatant glutamate levels were determined using an enzymatic assay. Expression regulation of molecules involved in vesicular glutamate release was examined by quantitative real-time PCR, and mechanisms of non-vesicular glutamate release were studied by pharmacological blocking experiments. The impact of CD8+ T cell-mediated glutamate liberation on neuronal viability was studied in acute brain slice preparations. Results: Following T cell receptor stimulation, CD8+ T cells acquire the molecular repertoire for vesicular glutamate release: (i) they upregulate expression of glutaminase required to generate glutamate via deamination of glutamine and (ii) they upregulate expression of vesicular proton-ATPase and vesicular glutamate transporters required for filling of vesicles with glutamate. Subsequently, CD8+ T cells release glutamate in a strictly stimulus-dependent manner. Upon repetitive T cell receptor stimulation, CD25high CD8+ T effector cells exhibit higher estimated single cell glutamate release rates than CD25low CD8+ T memory cells. Moreover, glutamate liberation by oligodendrocyte-reactive CD25high CD8+ T effector cells is capable of eliciting collateral excitotoxic cell death of neurons (despite glutamate re-uptake by glia cells and neurons) in intact CNS gray matter. Conclusion: Glutamate release may represent a crucial effector pathway of neural-antigen reactive CD8+ T cells, contributing to excitotoxicity in CNS inflammation.<br

The SARS-coronavirus-host interactome

Coronaviruses (CoVs) are important human and animal pathogens that induce fatal respiratory, gastrointestinal and neurological disease. The outbreak of the severe acute respiratory syndrome (SARS) in 2002/2003 has demonstrated human vulnerability to (Coronavirus) CoV epidemics. Neither vaccines nor therapeutics are available against human and animal CoVs. Knowledge of host cell proteins that take part in pivotal virus-host interactions could define broad-spectrum antiviral targets. In this study, we used a systems biology approach employing a genome-wide yeast-two hybrid interaction screen to identify immunopilins (PPIA, PPIB, PPIH, PPIG, FKBP1A, FKBP1B) as interaction partners of the CoV non-structural protein 1 (Nsp1). These molecules modulate the Calcineurin/NFAT pathway that plays an important role in immune cell activation. Overexpression of NSP1 and infection with live SARS-CoV strongly increased signalling through the Calcineurin/NFAT pathway and enhanced the induction of interleukin 2, compatible with late-stage immunopathogenicity and long-term cytokine dysregulation as observed in severe SARS cases. Conversely, inhibition of cyclophilins by cyclosporine A (CspA) blocked the replication of CoVs of all genera, including SARS-CoV, human CoV-229E and -NL-63, feline CoV, as well as avian infectious bronchitis virus. Non-immunosuppressive derivatives of CspA might serve as broad-range CoV inhibitors applicable against emerging CoVs as well as ubiquitous pathogens of humans and livestock