29,371 research outputs found

    Crystallization and preliminary crystallographic data for the augmenter of liver regeneration

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    A new cellular growth factor termed augmenter of liver regeneration (ALR) has been crystallized. ALR has been shown to have a proliferative effect on liver cells while at the same time producing an immunosuppressive effect on liver-resident natural killer cells and liver-resident mononuclear leukocytes. In addition, ALR appears to play an important role in the synthesis and stabilization of mitochondrial gene transcripts inactively regenerating cells. ALR crystals diffract to beyond 2 Å resolution and belong to space group P21212, with a = 125.1, b = 108.1 and c = 38.5 Å. Based on four molecules per asymmetric unit, the Matthews coefficient is calculated to be 2.16 Å3 Da-1 which corresponds to a solvent content of 43%

    Longevity of the Permian Emeishan mantle plume (SW China): 1 Ma, 8 Ma or 18 Ma?

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    After the formation of the ∼ 260 Ma Emeishan large igneous province, there were two volumetrically minor magmatic pulses at ∼ 252 Ma and ∼ 242 Ma, respectively. Alkaline mafic dykes intruding both 260 Ma and 252 Ma felsic plutons in the Panxi region, southwestern China, have compositions similar to the Emeishan flood basalts. One dyke is dated using the SHRIMP zircon U-Pb technique at 242 ± 2 Ma, ∼ 18 Ma younger than the start of Emeishan magmatism. The dykes have enriched light rare earth element patterns (La/YbN = 4.4-18.8) and trace element patterns similar to the Emeishan flood basalts and average ocean-island basalts. Some trace element ratios of the dykes (Zr/Nb = 3.8-8.2, La/Nb = 0.4-1.7, Ba/La = 7.5-25.6) are somewhat similar to EM1 source material, however, there are differences. Their εNd values (εNd = +2.6 and +2.7) and ISr( ISr = 0.704542 and 0.704554) ratios are indicative of a mantle source. Thus Emeishan magmatism may have lasted for almost 20 Ma after the initial eruption. However, geological evidence precludes the possibility that the post-260 Ma magmatic events were directly related to Emeishan magmatism, which began at and ended shortly after 260 Ma. The 252 Ma plutons and 242 Ma dykes represent volumetrically minor melting of the fossil Emeishan plume-head beneath the Yangtze crust. The 252 Ma magmatic event was likely caused by post-flood basalt extension of the Yangtze crust, whereas the 242 Ma event was caused by decompressional melting associated with the collision between the South China and North China blocks during the Middle Triassic. © 2008 Cambridge University Press.published_or_final_versio

    Cogging torque reduction of Bldc motor using level set based topology optimization incorporating with triangular finite element

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    Cogging torque in permanent-magnet brushless DC (BLDC) motor causes torque and speed ripples, as well as acoustic noise and vibration, especially in low speed and direct drive applications. In this paper, the stator core shape is optimized by using a level set based topology optimization to reduce cogging torque. The level set method can represent the precise boundary shape of structure and also deal with complex topology changes during the optimization process. Different from the conventional rectangular meshes, the level set technique based triangular finite element meshes are presented in this paper to deal with irregular domains. The comparison of cogging torque calculated before and after topology optimization verifies the advantages of the level set topology optimization based on triangular meshes. © 2010 - IOS Press and the authors. All rights reserved

    Screening of seven microsatellite markers for litter size in Xinong Saanen dairy goat

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    Seven microsatellite markers OarAE101, BM1329, OarHH55, BM143, BMS2508, OarAE129 and OarFCB11 closely associated with high reproduction trait in sheep were analyzed for polymorphisms in Xinong Saanen dairy goat. The results indicated that there were high genetic polymorphisms at six microsatellite loci. The number of effective alleles (Ne), polymorphism information content (PIC) and average heterozygosity (He) were the highest at OarFCB11 and the lowest at OarAE129 in Xinong Saanen dairy goat. The analysis of the effect of the six polymorphisms microsatellite loci on the litter size of Xinong Saanen dairy goat indicated that these polymorphisms microsatellite loci had positive effect on the litter size.Key words: Microsatellite markers, Xinong Saanen dairy goat, genetic polymorphism, litter size

    Induction of resistance in cucumber against seedling damping-off by plant growth-promoting rhizobacteria (PGPR) Bacillus megaterium strain L8

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    Bacillus megaterium L8, a plant growth-promoting rhizobacterium (PGPR), was isolated and evaluated for its ability to induce resistance in cucumber against seedling damping-off caused by Pythium aphanidermatum. Root-splitting challenge experiments showed that L8 treatment of cucumber roots more effectively suppressed seedling damping-off than did the control as judged by seedling survival rate (83.45 versus 31.68% at 28 days), indicating that strain L8 is capable of inducing systemic disease resistance in cucumber. To explore the potential mechanism underlying the induced systemic resistance (ISR) mediated by L8, the expression profile of several plant defense-related enzymes: superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) were monitored in the roots treated with L8 or P. aphanidermatum and untreated leaves in a time course of 13 days. Levels of SOD, POD, CAT, PPO and PAL activities in the treated roots and untreated leaves of cucumber seedlings were all significantly higher as compared with the control and respectively peaked in the roots at 3, 3, 5, 5 and 5 days and correspondingly in the leaves at 5, 3, 5, 5 and 5 days post-inoculation. The enhanced expression patterns of the above enzymes following L8 or P. aphanidermatum treatment suggested that systemic induction of plant defense enzymes by L8 might account for its ability to provide effective protection for cucumber from seedling damping-off caused by the soil-borne fungal pathogen P. aphanidermatum.Key words: Plant growth-promoting rhizobacteria (PGPR), defense enzymes, damping-off of cucumber seedlings, induced resistance

    Two-dimensional elemental operator for modeling the vectorial hysteresis of soft magnetic composite material

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    © 2015 IEEE. This paper presents a two-dimensional elemental operator with biaxial anisotropy based on the physical mechanisms of the cubic textured magnetic materials, and deduces an analytical expression of the direct relationship between magnetic field strength H and magnetization M for a single elemental operator by the partial approximate substitutions. To verify the proposed model, the magnetic hysteresis of a soft magnetic composite material SOMALOYTM 500 under alternating excitations was simulated and compared with the experimental results obtained by a 3D magnetic property tester. The results suggest that the proposed approach can be a useful tool in the modeling of vectorial magnetic hysteresis and the calculation of iron loss in practical engineering electromagnetic field analysis

    Modeling the stress dependence of magnetic hysteresis based on Stoner-Wohlfarth theory

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    © 2015 IEEE. This paper presents an improved approach for simulating magnetic hysteresis, which takes into account the effect of applied stress, based on an extended Stoner-Wohlfarth (S-W) model. Meanwhile, the S-W asteroid rotates and shrinks, and the stable direction of magnetization of the particle can be calculated from the new energy minimum conditions. This developed model is applied to analyze the magnetic hysteresis phenomenon of a soft magnetic composite (SMC) material under different compaction process, and the results of simulations are in good quantitative agreement with experimental data

    Giant magnetoelectric effect of a hybrid of magnetostrictive and piezoelectric composites

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    Author name used in this publication: H. L. W. Chand2002-2003 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Robust optimization in HTS cable based on design for six sigma

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    The nonuniform ac current distribution among the multilayer conductors in a high-temperature superconducting (HTS) cable reduces the current capacity and increases the ac loss. Various numerical simulation techniques and optimization methods have been applied in structural optimization of HTS cables. While the existence of fluctuation in design variables or operation conditions has a great influence on the cable quality, in order to eliminate the effects of parameter perturbations in design and to improve the design efficiency, a robust optimization method based on design for six sigma (DFSS) is presented in this paper. The optimization results show that the proposed optimization procedure can not only achieve a uniform current distribution, but also improve significantly the reliability and robustness of the HTS cable quality, comparing with those by using the particle swarm optimization. © 2008 IEEE
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