718 research outputs found

    Enzymes of Hevea brasiliensis latex. Adenylate Kinase, Sulphate Adenylyitransferase (ATP-sulphurylase) and Thiosulphate Sulphurtransferase (Rhodanese)

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    Penyiasatan fasa serum dari lateks Hevea brasiliensis mendalilkan kewujudan ketiga enzim yang beriku t: adenilat kinase EC 2.7.4.3; sulfat adenililtransferase (ATP-sulfurilase) EC 2.7.7.4; tiosulfat sulfurtransferase (rodanese) EC 2.8.1.1

    Scale-invariant magnetoresistance in a cuprate superconductor

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    The anomalous metallic state in high-temperature superconducting cuprates is masked by the onset of superconductivity near a quantum critical point. Use of high magnetic fields to suppress superconductivity has enabled a detailed study of the ground state in these systems. Yet, the direct effect of strong magnetic fields on the metallic behavior at low temperatures is poorly understood, especially near critical doping, x=0.19x=0.19. Here we report a high-field magnetoresistance study of thin films of \LSCO cuprates in close vicinity to critical doping, 0.161x0.1900.161\leq x\leq0.190. We find that the metallic state exposed by suppressing superconductivity is characterized by a magnetoresistance that is linear in magnetic field up to the highest measured fields of 8080T. The slope of the linear-in-field resistivity is temperature-independent at very high fields. It mirrors the magnitude and doping evolution of the linear-in-temperature resistivity that has been ascribed to Planckian dissipation near a quantum critical point. This establishes true scale-invariant conductivity as the signature of the strange metal state in the high-temperature superconducting cuprates.Comment: 10 pages, 3 figure

    Composition, degradation and utilization of endosperm during germination in the oil palm (Elaeis guineensis Jacq.)

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    The insoluble carbohydrate and lipid fractions, and α-D-galactosidase, β-D-mannosidase and isocitrate lyase activities were studied in the various tissues of oil palm (Elaeis guineensis Jacq.) kernels prior to and during germination. In ungerminated kernels insoluble carbohydrate and lipid constituted 36 and 47% of endosperm dry weight respectively. During germination the thick endosperm cell walls became markedly thinner, concurrent with a significant decrease in the percentage of insoluble carbohydrate and an increase in α-galactosidase and β-mannosidase activity in both degraded and residual endosperm. The proportion of lipid in degraded endosperm also increased significantly. The insoluble carbohydrate appears to be a galactomannan located in the secondary walls of the endosperm. No galactomannan was detected in oil palm embryos or haustoria. Isocitrate lyase was present in, and confined to, tissues of the haustorium of germinating kernels. The enzyme was not active in endosperm at any stage of germination, nor was it active in embryos before or at the end of imbibition. The results suggest that galactomannan is the second largest component of oil palm endosperm and that it is utilized more rapidly than lipid during the early stages of germination. The fact that isocitrate lyase activity is confined to the haustorium suggests that in Elaeis gluconeogenesis, the conversion of triglyceride to carbohydrate, takes place entirely within the cotyledon of the seed

    The Effect of 28 Days of Beta-Alanine Supplementation on Repeated-Sprint Ability

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    Please view abstract in the attached PDF file

    Axial Vector JPC=1++J^{PC}=1^{++} Charmonium and Bottomonium Hybrid Mass Predictions with QCD Sum-Rules

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    Axial vector (JPC=1++)(J^{PC}=1^{++}) charmonium and bottomonium hybrid masses are determined via QCD Laplace sum-rules. Previous sum-rule studies in this channel did not incorporate the dimension-six gluon condensate, which has been shown to be important for 11^{--} and 0+0^{-+} heavy quark hybrids. An updated analysis of axial vector charmonium and bottomonium hybrids is presented, including the effects of the dimension-six gluon condensate. The axial vector charmonium and bottomonium hybrid masses are predicted to be 5.13 GeV and 11.32 GeV, respectively. We discuss the implications of this result for the charmonium-like XYZ states and the charmonium hybrid multiplet structure observed in recent lattice calculations.Comment: 10 pages, 7 figures. Updated to match published versio

    Periscope Proteins are variable-length regulators of bacterial cell surface interactions

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    Changes at the cell surface enable bacteria to survive in dynamic environments, such as diverse niches of the human host. Here, we reveal “Periscope Proteins” as a widespread mechanism of bacterial surface alteration mediated through protein length variation. Tandem arrays of highly similar folded domains can form an elongated rod-like structure; thus, variation in the number of domains determines how far an N-terminal host ligand binding domain projects from the cell surface. Supported by newly available long-read genome sequencing data, we propose that this class could contain over 50 distinct proteins, including those implicated in host colonization and biofilm formation by human pathogens. In large multidomain proteins, sequence divergence between adjacent domains appears to reduce interdomain misfolding. Periscope Proteins break this “rule,” suggesting that their length variability plays an important role in regulating bacterial interactions with host surfaces, other bacteria, and the immune system

    Loss of the RNA polymerase III repressor MAF1 confers obesity resistance.

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    MAF1 is a global repressor of RNA polymerase III transcription that regulates the expression of highly abundant noncoding RNAs in response to nutrient availability and cellular stress. Thus, MAF1 function is thought to be important for metabolic economy. Here we show that a whole-body knockout of Maf1 in mice confers resistance to diet-induced obesity and nonalcoholic fatty liver disease by reducing food intake and increasing metabolic inefficiency. Energy expenditure in Maf1(-/-) mice is increased by several mechanisms. Precursor tRNA synthesis was increased in multiple tissues without significant effects on mature tRNA levels, implying increased turnover in a futile tRNA cycle. Elevated futile cycling of hepatic lipids was also observed. Metabolite profiling of the liver and skeletal muscle revealed elevated levels of many amino acids and spermidine, which links the induction of autophagy in Maf1(-/-) mice with their extended life span. The increase in spermidine was accompanied by reduced levels of nicotinamide N-methyltransferase, which promotes polyamine synthesis, enables nicotinamide salvage to regenerate NAD(+), and is associated with obesity resistance. Consistent with this, NAD(+) levels were increased in muscle. The importance of MAF1 for metabolic economy reveals the potential for MAF1 modulators to protect against obesity and its harmful consequences
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