Enhanced Out-of-plane Emission of K+ Mesons observed in Au+Au Collisions at 1 AGeV

The azimuthal angular distribution of K+ mesons has been measured in Au + Au collisions at 1 AGeV. In peripheral and semi-central collisions, K+ mesons preferentially are emitted perpendicular to the reaction plane. The strength of the azimuthal anisotropy of K+ emission is comparable to the one of pions. No in-plane flow was found for K+ mesons near projectile and target rapidity.Comment: Accepted for publication in Phys. Rev.Let

Development and Performance of the Nanoworkbench: A Four Tip STM for Electrical Conductivity Measurements Down to Sub-micrometer Scales

A multiple-tip ultra-high vacuum (UHV) scanning tunneling microscope (MT-STM) with a scanning electron microscope (SEM) for imaging and molecular-beam epitaxy growth capabilities has been developed. This instrument (nanoworkbench) is used to perform four-point probe conductivity measurements at micrometer spatial dimension. The system is composed of four chambers, the multiple-tip STM/SEM chamber, a surface analysis and preparation chamber, a molecular-beam epitaxy chamber and a load-lock chamber for fast transfer of samples and probes. The four chambers are interconnected by a unique transfer system based on a sample box with integrated heating and temperature-measuring capabilities. We demonstrate the operation and the performance of the nanoworkbench with STM imaging on graphite and with four-point-probe conductivity measurements on a silicon-on-insulator (SOI) crystal. The creation of a local FET, whose dimension and localization are respectively determined by the spacing between the probes and their position on the SOI surface, is demonstrated.Comment: 39 pages, 15 figure

Medium Effects in Kaon and Antikaon Production in Nuclear Collisions at Subthreshold Beam Energies

Production cross sections of K$^+$ and K$^-$ mesons have been measured in C+C collisions at beam energies per nucleon below and near the nucleon-nucleon threshold. At a given beam energy, the spectral slopes of the K$^-$ mesons are significantly steeper than the ones of the K$^+$ mesons. The excitation functions for K$^+$ and K$^-$ mesons nearly coincide when correcting for the threshold energy. In contrast, the K$^+$ yield exceeds the K$^-$ yield by a factor of about 100 in proton-proton collisions at beam energies near the respective nucleon-nucleon thresholds.Comment: Accepted for publication in Phys. Rev. Let

Predicting the impact of Lynch syndrome-causing missense mutations from structural calculations

Accurate methods to assess the pathogenicity of mutations are needed to fully leverage the possibilities of genome sequencing in diagnosis. Current data-driven and bioinformatics approaches are, however, limited by the large number of new variations found in each newly sequenced genome, and often do not provide direct mechanistic insight. Here we demonstrate, for the first time, that saturation mutagenesis, biophysical modeling and co-variation analysis, performed in silico, can predict the abundance, metabolic stability, and function of proteins inside living cells. As a model system, we selected the human mismatch repair protein, MSH2, where missense variants are known to cause the hereditary cancer predisposition disease, known as Lynch syndrome. We show that the majority of disease-causing MSH2 mutations give rise to folding defects and proteasome-dependent degradation rather than inherent loss of function, and accordingly our in silico modeling data accurately identifies disease-causing mutations and outperforms the traditionally used genetic disease predictors. Thus, in conclusion, in silico biophysical modeling should be considered for making genotype-phenotype predictions and for diagnosis of Lynch syndrome, and perhaps other hereditary diseases

Azimuthally anisotropic emission of pions in symmetric heavy-ion collisions

Triple differential cross sections d3 sigma /dp3 for charged pions produced in symmetric heavy-ion collisions were measured with the KaoS magnetic spectrometer at the heavy-ion synchrotron facility SIS at GSI. The correlations between the momentum vectors of charged pions and the reaction plane in 197Au+197Au collisions at an incident energy of 1 GeV/nucleon were determined. We observe, for the first time, an azimuthally anisotropic distribution of pions, with enhanced emission perpendicular to the reaction plane. The anisotropy is most pronounced for pions of high transverse momentum in semicentral collisions

A Chaperone Trap Contributes to the Onset of Cystic Fibrosis

Protein folding is the primary role of proteostasis network (PN) where chaperone interactions with client proteins determine the success or failure of the folding reaction in the cell. We now address how the Phe508 deletion in the NBD1 domain of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) protein responsible for cystic fibrosis (CF) impacts the binding of CFTR with cellular chaperones. We applied single ion reaction monitoring mass spectrometry (SRM-MS) to quantitatively characterize the stoichiometry of the heat shock proteins (Hsps) in CFTR folding intermediates in vivo and mapped the sites of interaction of the NBD1 domain of CFTR with Hsp90 in vitro. Unlike folding of WT-CFTR, we now demonstrate the presence of ΔF508-CFTR in a stalled folding intermediate in stoichiometric association with the core Hsps 40, 70 and 90, referred to as a ‘chaperone trap’. Culturing cells at 30 C resulted in correction of ΔF508-CFTR trafficking and function, restoring the sub-stoichiometric association of core Hsps observed for WT-CFTR. These results support the interpretation that ΔF508-CFTR is restricted to a chaperone-bound folding intermediate, a state that may contribute to its loss of trafficking and increased targeting for degradation. We propose that stalled folding intermediates could define a critical proteostasis pathway branch-point(s) responsible for the loss of function in misfolding diseases as observed in CF

Team 12: Joint Dynamic Allocation of Fires and Sensors: Experimental Interface and Analysis

from Scythe : Proceedings and Bulletin of the International Data Farming Community, Issue 2 Workshop 14The Joint Dynamic Allocation of Fires and Sensors (JDAFS) simulation is a publicly available discrete event simulation that accounts for first order combat effects using Army approved algorithms. It couples dynamic allocation of resources such as unmanned platforms and artillery assets using optimization to a simulation to render better representations of network enabled warfare. The current configuration is not user friendly when entering the DOE factors. This is problematic for a number of reasons. First, the potential for data entry errors is significant when entering a large volume of numbers. Second, the data entry is not only time consuming but potentially expensive. Finally, an operator/analyst needs to be present as the runs are completed in order to start the next design point evolution. The potential for errors and the inherent inefficiencies warrant the development of a method to easily run a DOE if JDAFS is to be more widely used

Measured Performance Signature Method

The performance correction of systems that have many thermally integrated components is complex and subject to error if individual component misperformance and/or deterioration is present. The performance correction involves a set of equations or curves which relate the expected changes in dependent performance parameters (i.e. output, fuel consumption, etc.) to changes in the dependent parameters defining a standard condition (i.e. ambient temperatures, pressure, fuel composition, etc.). These relations and curves are usually generated by vendor performance programs which reflect the design data of the given plant components. However, such relations and curves applied to the overall correction of thermally integrated components can introduce significant correction error if the equipment performance differs from the expected design values. This can be particularly important in acceptance testing and base line monitoring of older plants where performance deterioration has occurred. The performance testing or monitoring of power plants requires that results be corrected to a given reference or standard condition. This correction procedure may be used in various applications, including determining compliance to a guarantee that is specified to a given reference, to compare different plants under similar operating conditions, and/or to track the performance of a given plant with time on a consistent basis. A Measured Performance Signature (MPS) approach has been developed to improve integrated system performance corrections. This procedure is useful for acceptance testing and continuous performance monitoring of industrial cogeneration plants or any energy system. The plant performance signature, is determined from on-line measurements, and corrected to a specified reference. This procedure provides information for adaptive on-line optimum dispatch, equipment performance monitoring, or for conducting system "what if' scenarios. The MPS is a very useful technique which may be applied to Acceptance Testing Monitoring and Operations Optimization. The technique is general and can be applied to all types of plant equipment and configurations