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At least 1,675 records · Page 93

The R35 residue of the influenza A virus NS1 protein has minimal effects on nuclear localization but alters virus replication through disrupting protein dimerization

The influenza A virus NS1 protein has a nuclear localization sequence (NLS) in the amino terminal region. This NLS overlaps sequences that are important for RNA binding as well as protein dimerization. To assess the significance of the NS1 NLS on influenza virus replication, the NLS amino acids were individually mutated to alanines and recombinant viruses encoding these mutations were rescued. Viruses containing NS1 proteins with mutations at R37, R38 and K41 displayed minimal changes in replication or NS1 protein nuclear localization. Recombinant viruses encoding NS1 R35A were not recovered but viruses containing second site mutations at position D39 in addition to the R35A mutation were isolated. The mutations at position 39 were shown to partially restore NS1 protein dimerization but had minimal effects on nuclear localization. These data indicate that the amino acids in the NS1 NLS region play a more important role in protein dimerization compared to nuclear localization. - Highlights: • Mutations were introduced into influenza NS1 NLS1. • NS1 R37A, R38A, K41A viruses had minimal changes in replication and NS1 localization. • Viruses from NS1 R35A rescue all contained additional mutations at D39. • NS1 R35A D39X mutations recover dimerization lost in NS1 R35A mutations. • These results reaffirm the importance of dimerization for NS1 protein function.

60 APPLIED LIFE SCIENCES↗

Identification of amino-acid residues in the V protein of peste des petits ruminants essential for interference and suppression of STAT-mediated interferon signaling

Peste des petits ruminants virus (PPRV) causes a fatal disease in small ruminants. V protein of PPRV plays a pivotal role in interfering with host innate immunity by blocking IFNs signaling through interacting with STAT1 and STAT2. In the present study, the results demonstrated that PPRV V protein blocks IFN actions in a dose dependent manner and restrains the translocation of STAT1/2 proteins. We speculate that the translocation inhibition might be caused by the interfering of the downstream of STAT protein. Mutagenesis defines that Cys cluster and Trp motif of PPRV V protein are essential for STAT-mediated IFN signaling. These findings give a new sight for the further studies to understand the delicate mechanism of PPRV to escape the IFN signaling. - Highlights: • PPRV V protein inhibits type I IFN production and blocks its activation. • PPRV V protein negatively regulates activation of ISRE and GAS promoter. • PPRV V protein inhibits nuclear translocation of STAT protein by non-degradation. • PNT and VCT domain of PPRV V protein inhibit IFN transduction. • PPRV V protein binds with STAT protein via some conserved motifs.

60 APPLIED LIFE SCIENCES↗

Structural Basis for Differential Insertion Kinetics of dNMPs Opposite a Difluorotoluene Nucleotide Residue

We have recently challenged the widely held view that 2,4-difluorotoluene (dF) is a nonpolar isosteric analogue of the nucleotide dT, incapable of forming hydrogen bonds (HBs). To gain a further understanding for the kinetic preference that favors dAMP insertion opposite a templating dF, a result that mirrors the base selectivity that favors dAMP insertion opposite dT by RB69 DNA polymerase (RB69pol), we determined presteady-state kinetic parameters for incorporation of four dNMPs opposite dF by RB69pol and solved the structures of corresponding ternary complexes. We observed that both the F2 and F4 substituent of dF in these structures serve as HB acceptors forming HBs either directly with dTTP and dGTP or indirectly with dATP and dCTP via ordered water molecules. We have defined the shape and chemical features of each dF/dNTP pair in the RB69pol active site without the corresponding phosphodiester-linkage constraints of dF/dNs when they are embedded in isolated DNA duplexes. These features can explain the kinetic preferences exhibited by the templating dF when the nucleotide incorporation is catalyzed by wild type RB69pol or its mutants. We further show that the shapes of the dNTP/dF nascent base pair differ markedly from the corresponding dNTP/dT in the pol active site and that these differences have a profound effect on their incorporation efficiencies.

08 HYDROGEN↗

Confocal detection of Rayleigh scattering for residual stress measurement in chemically tempered glass

A new optical method is presented for evaluation of the stress profile in chemically tempered (chemically strengthened) glass based on confocal detection of scattered laser beam. Theoretically, a lateral resolution of 0.2 μm and a depth resolution of 0.6 μm could be achieved by using a confocal microscope with high-NA immersion objective. The stress profile in the 250 μm thick surface layer of chemically tempered lithium aluminosilicate glass was measured with a high spatial resolution to illustrate the capability of the method. The confocal method is validated using transmission photoelastic and Na{sup +} ion concentration profile measurement. Compositional influence on the stress-optic coefficient is calculated and discussed. Our method opens up new possibilities for three-dimensional scattered light tomography of mechanical imaging in birefringent materials.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Laser methods for detecting explosive residues on surfaces of distant objects

The basic methods of laser spectroscopy that are used for standoff detection and identification of explosive traces in the form of particles on the surfaces of objects tested under real or close-toreal conditions are briefly considered. The advantages and drawbacks of all methods are discussed and their characteristics are compared. Particular attention has been given to the prospects of development and practical implementation of the technologies discussed and justification of their most preferred applications. (review)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Acid Evaporation of Ultima Gold™ AB Liquid Scintillation Cocktail Residue

Prior analyses of samples from the F/H Lab solutions showed the presence of diisopropylnapthalene (DIN), a major component of Ultima Gold™ AB liquid scintillation cocktail (LSC). These solutions are processed through H-Canyon Tank 10.5 and ultimately through the 17.8E evaporator. Similar solutions originated in SRNL streams sent to the same H Canyon tanks. This study examined whether the presence of these organics poses a process-significant hazard for the evaporator.

36 MATERIALS SCIENCE↗

Final Report: Characterization of Canister Mockup Weld Residual Stresses

Stress corrosion cracking (SCC) of interim storage containers has been indicated as a high priority data gap by the Department of Energy (DOE) (Hanson et al., 2012), the Electric Power Research Institute (EPRI, 2011), the Nuclear Waste Technical Review Board (NWTRB, 2010a), and the Nuclear Regulatory Commission (NRC, 2012a, 2012b). Uncertainties exist in terms of the environmental conditions that prevail on the surface of the storage containers, the stress state within the container walls associated both with weldments as well as within the base metal itself, and the electrochemical properties of the storage containers themselves. The goal of the work described in this document is to determine the stress states that exists at various locations within a typical storage canister by evaluating the properties of a full-diameter cylindrical mockup of an interim storage canister. This mockup has been produced using the same manufacturing procedures as the majority of the fielded spent nuclear fuel interim storage canisters. This document describes the design and procurement of the mockup and the characterization of the stress state associated with various portions of the container. It also describes the cutting of the mockup into sections for further analyses, and a discussion of the potential impact of the results from the stress characterization effort.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Estimating the Impact of Residual Value for Electricity Generation Plants on Capital Recovery, Levelized Cost of Energy, and Cost to Consumers

There is often a benefit to continue operating electricity generating assets after their initial contracts expire. This report discusses these benefits and associated risks, using data and illustrative calculations. The key findings are: the realized operational lives of generation technologies before retirement are typically much longer than typical measures of economic lives. The cost impact of a life extension can be comparable to the impact of other factors considered for generation investment decisions, and suggests that R&D and commercial efforts to extend generator life may be valuable. Refurbishment has a useful and economic role, but the option is often neglected during initial investment. Estimating follow-on value at the time of the original investment is complex and often neglected, but may be valuable.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Calibration of X-Ray Diffraction Instruments for Residual-Stress Measurement

The deficiencies of existing standard iron and nickel samples for calibration by means of X-ray diffraction are noted. These standards cannot be used in calibration by magnetic noise recording. A new calibration method based on X-ray diffraction is proposed, using plane samples of the material employed in the manufacture of the actual structures. Theoretical analysis provides the basis for the development of null standards in which a plane sample is deformed by pure flexure or in a cantilever-beam configuration.

42 ENGINEERING↗

Performance of Residual Carrier Array Feed Combining in Correlated Noise

An array feed combining system for the recovery of SNR loss due to antenna reflector deformation has been implemented and is currently being evaluated on the Jet Propulsion Laboratory 34 meter DSS-13 antenna. In this system, the defocused signal field captured by a focal plane array feed is recovered using real-time signal processing and signal combining techniques. The current signal processing and signal combining algorithms are optimum under the assumption that the white Gaussian noise processes in the received signals from different array elements are mutually uncorrelated. Experimental data at DSS-13 indicate that these noise processes are indeed mutually correlated. The main result of this paper is an analytical derivation of the actual SNR performance of the current suboptimal signal combining algorithm in this correlated noises environment. The analysis here shows that the combined signal SNR can either be improved or degraded depending on the relation between the array signal and noise correlation coefficient phases. Further performance improvement will require the development of signal combining methods that take into account the correlated noises.

Residual↗