[en] The authors summarize the results of two recent searches for flavor-changing neutral current, lepton-flavor violating, and lepton-number violating decays of D⁺, D_s⁺, and D⁰ mesons (and their antiparticles) into modes containing muons and electrons. using data from Fermilab charm hadroproduction experiment E791, they examined D⁺ and D_s⁺ πellell and Κellell decay modes and the D⁰ dilepton decay modes containing either ell⁺ell^-, a ρ⁰, bar Κ*⁰, or φ vector meson, or a non-resonant ππ, Κπ, or ΚΚ pair of pseudoscalar mesons. No evidence for any of these decays was found. Therefore, the authors presented branching-fraction upper limits at 90% confidence level for the 51 decay modes examined. Twenty-six of these modes had no previously reported limits, and eighteen of the remainder were reported with significant improvements over previously published results

[en] High energy physics experiments are currently recording large amounts of data and in a few years will be recording prodigious quantities of data. New methods must be developed to handle this data and make analysis at universities possible. We examine some techniques that exploit recent developments in commodity hardware. We report on tests of redundant arrays of integrated drive electronics (IDE) disk drives for use in offline high energy physics data analysis. IDE redundant array of inexpensive disks (RAID) prices now are less than the cost per terabyte of million-dollar tape robots. The arrays can be scaled to sizes affordable to institutions without robots and used when fast random access at low cost is important

[en] The cytoplasmic domains of viral glycoproteins influence the trafficking and subcellular localization of the glycoproteins and their incorporation into virions. They also promote correct virus morphology and viral budding. The cytoplasmic domains of murine-leukemia-virus envelope-protein TM subunits regulate membrane fusion. During virion maturation the carboxy-terminal 16 amino acid residues of the TM protein are removed by the retroviral protease. Deletion of these residues activates envelope-protein-mediated membrane fusion. Our quantitative analysis of the effects of Moloney murine leukemia virus TM mutations on envelope-protein function support the proposition that a trimeric coiled coil in the TM cytoplasmic domain inhibits fusion. The data demonstrate that cleavage of the TM cytoplasmic domain is not required for viral entry and provide evidence for a model in which fusogenic and nonfusogenic conformations of the envelope protein exists in an equilibrium that is regulated by the cytoplasmic domain. In addition, a conserved tyrosine residue in the TM cytoplasmic domain was shown to play an important role in envelope-protein incorporation into retroviral particles

[en] Retrovirus packaging cell lines that express the Moloney murine leukemia virus gag, pol, and env genes and a retroviral vector genome can produce virus particles that are capable of transducing cells. Normally if the packaging cell line does not produce a functional viral fusion glycoprotein, such as the retroviral envelope protein or a foreign viral glycoprotein, then the viruses will be incapable of transducing cells. We have found that incubating envelope protein-deficient virus particles bound to cells with chlorpromazine leads to transduction. Chlorpromazine (CPZ) is a membrane-active reagent that is commonly used to induce the hemifusion to fusion transition when membrane fusion is mediated by partially defective viral glycoproteins. The concentration and pH dependence of the promotion of transduction by CPZ is consistent with a role for CPZ micelle formation in viral entry. These data indicate that caution is warranted when experiments concerning membrane fusion completion promoted by CPZ are analyzed

[en] Recent seismic events have underlined the risks nuclear dry storage casks (DSCs) are exposed. Dominion Virginia Power's North Ann during Virginia 5.8 earthquake, August 2011: - 25 of 27 DSCs moved on their concrete pad; - DSCs shifted from 1.0 to 4 1/2 inches; - Metal components were not damaged; - No radiation was released. The main goals of this study is to evaluate the long-term seismic performance of DSCs using experimental tests. Through use of Scaled DSC Specimens on the UNR six Degree-of-Freedom (DOF) Shaking Table. Scaled model specimen shall satisfy the following: - Model aspect ratio shall cover the range in the available commercial DSCs; - Scaled 1/2.5 specimens shall be presentative for the actual prototype (specially under vertical excitation); - Designed specimen shall sustain handling, sliding and impact during testing. Selected evaluation basis earthquakes: - Near Field Earthquake (M6.0 at 2 km); - Far Field Earthquake (M8.0 at 20 km). The level of spectral acceleration using NUREG 6728 seismic hazard curves. Developed for the following return periods: - 1,000-year return period; - 30,000-year return period. Design: - Design handling system for overpack and MPC; - Check stresses on the outer cylindrical shell of the overpack in case of using anchorage system for the DSCs; - Check resulted stresses due to impact of the scaled specimen on the supporting concrete pad; - Check safety of shell thicknesses; - Design of connections between different parts; - Design of the concrete pads to resist impact during the test. Future Plans: - Evaluate the long-term seismic performance of the existing dry storage casks in U.S. and develop guidelines for re-licensing operating periods of DSCs. - Provide a performance based design guidelines for DSCs to maintain its safety against earthquakes

No abstract available

[en] Dry Storage Casks (DSCs) store spent nuclear fuel (SNF), usually at sites contiguous to nuclear power plants known as Independent Spent Fuel Storage Installation (ISFSI). DSCs have been considered as a temporary storage solution, and are usually licensed for 20 years, which can be extended up to an operating periods of 60 years. Recently, however, DSCs have been considered as a potential mid-term solution for hundreds of years. This consideration requires reevaluation of DSC performance under a larger seismic hazard. That leads to larger horizontal and vertical accelerations. This study is a part of a research project evaluating the seismic response of free-standing DSCs under long return period seismic events. This article assess whether the response of free-standing structures under seismic excitation is repeatable. For this purpose, experimental tests were conducted using a six degree-of-freedom (6DOF) shake table. During the experimental tests, several ground motions were repeated multiple times to obtain the dynamic response under identical loading conditions. Scaled casks of four aspect ratios (radius to centroidal height ratio, r/h_cg) were studied: 0.39, 0.43, 0.55 and 0.62. The specimens studied are considered to be 1:2.5 and 1:3.5 scaled model of generic prototype casks. The experimental results show that a small change in initial conditions leads to change in the boundary condition of moving bodies and in combination with acceleration being applied at different frequencies contained within the applied ground motions may lead to a large variation in the response. (authors)

[en] Recombinant D. radiodurans TrxR with a His tag at the N-terminus was expressed in Escherichia coli and purified by metal-affinity chromatography. The protein was crystallized using the sitting-drop vapour-diffusion method in the presence of 35% PEG 4000, 0.2 M ammonium acetate and citric acid buffer pH 5.1 at 293 K. Deinococcus radiodurans, a Gram-positive bacterium capable of withstanding extreme ionizing radiation, contains two thioredoxins (Trx and Trx1) and a single thioredoxin reductase (TrxR) as part of its response to oxidative stress. Thioredoxin reductase is a member of the family of pyridine nucleotide-disulfide oxidoreductase flavoenzymes. Recombinant D. radiodurans TrxR with a His tag at the N-terminus was expressed in Escherichia coli and purified by metal-affinity chromatography. The protein was crystallized using the sitting-drop vapour-diffusion method in the presence of 35% PEG 4000, 0.2 M ammonium acetate and citric acid buffer pH 5.1 at 293 K. X-ray diffraction data were collected on a cryocooled crystal to a resolution of 1.9 Å using a synchrotron-radiation source. The space group was determined to be P3₂21, with unit-cell parameters a = b = 84.33, c = 159.88 Å. The structure of the enzyme has been solved by molecular-replacement methods and structure refinement is in progress

[en] Single crystals of the holoenzyme (1R,6R)-2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate synthase with ThDP and Mn²⁺ as cofactors were obtained by the hanging-drop vapour-diffusion method with 35% ethylene glycol as precipitant. Apoenzyme crystals were obtained by sitting-drop vapour diffusion with 70% MPD. (1R,6R)-2-Succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate (SHCHC) synthase, also called MenD, participates in the menaquinone (vitamin K₂) biosynthetic pathway. The enzyme is a part of the superfamily of ThDP-dependent enzymes; however, it is the only enzyme known to catalyze a Stetter-like 1,4-addition of a ThDP adduct to the β-carbon of an unsaturated carboxylate. This is the first reported crystallization of the apoenzyme and holoenzyme forms of MenD. The apoenzyme crystals were obtained by sitting-drop vapour diffusion with 70% MPD. However, the crystals were too small to collect diffraction data and a search for better conditions was not successful. Single crystals of the holoenzyme with ThDP and Mn²⁺ as cofactors were obtained by the hanging-drop vapour-diffusion method with 35% ethylene glycol as precipitant. Diffraction data were collected on a cryocooled crystal to a resolution of 2.0 Å at BioCARS, Advanced Photon Source (APS), Chicago, IL, USA. The crystal was found to belong to space group P2₁2₁2₁, with unit-cell parameters a = 106.86, b = 143.06, c = 156.85 Å, α = β = γ = 90°

[en] UDP-galactopyranose mutase was crystallized using the microbatch method. The crystals diffracted to 2.36 Å resolution using synchrotron radiation. UDP-galactopyranose mutase (UGM) catalyzes the interconversion of UDP-galactopyranose and UDP-galactofuranose. A UGM–substrate complex from Deinococccus radiodurans has been expressed, purified and crystallized. Crystals were obtained by the microbatch-under-oil method at room temperature. The crystals diffracted to 2.36 Å resolution at the Canadian Light Source The space group was found to be P2₁2₁2₁, with unit-cell parameters a = 134.0, b = 176.6, c = 221.6 Å. The initial structure solution was determined by molecular replacement using UGM from Mycobacterium tuberculosis as a template model