5,185 research outputs found

    Isolation, sequence identification and tissue expression profile of a novel ribokinase gene (RBKS) from Chinese Banna mini-pig inbred line (BMI)

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    The complete expressed sequence tag (CDS) sequence of Banna mini-pig inbred line (BMI) ribokinase gene (RBKS) was amplified using the reverse transcription-polymerase chain reaction (RT-PCR) based on the conserved sequence information of the cattle or other mammals and known highly homologous swine ESTs. This novel gene was then deposited into NCBI database and assigned to accession number JF944892. Sequence analysis revealed that the BMI RBKS encodes a protein of 323 amino acids that has high homology with the ribokinase proteins of seven species: cattle (99%), horse (99%), orangutan (99%), human (89%), monkey (89%), rat (88%) and mouse (80%). The phylogenetic tree analysis revealed that the BMI RBKS gene has a closer genetic relationship with the RBKS genes of bovine and horse than with those of orangutan, human, monkey, rat and mouse. Analysis by RT-PCR showed that BMI RBKS gene was over-expressed in ovary and lung, moderately expressed in spleen, nerve fiber, large intestine and diencephalon, weakly expressed in heart, skin, muscle, small intestine, midbrain, kidney and fat, while almost silent in other five tissues. Four microRNA target sites were predicted in the CDS of BMI RBKS mRNA for further study of this gene in the future. The 3D structure of the RBKS by homology modeling was similar to that of human ribokinase (2fv7). Our experiment will establish a foundation for further insight into this swine gene.Key words: Banna mini-pig inbred line (BMI), pig, ribokinase gene (RBKS), tissue expression analysis, homology modelin

    Time-gated orthogonal scanning automated microscopy (OSAM) for high-speed cell detection and analysis

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    We report a new development of orthogonal scanning automated microscopy (OSAM) incorporating time-gated detection to locate rare-event organisms regardless of autofluorescent background. The necessity of using long-lifetime (hundreds of microseconds) luminescent biolabels for time-gated detection implies long integration (dwell) time, resulting in slow scan speed. However, here we achieve high scan speed using a new 2-step orthogonal scanning strategy to realise on-the-fly time-gated detection and precise location of 1-μm lanthanide-doped microspheres with signal-to-background ratio of 8.9. This enables analysis of a 15...mm × 15...mm slide area in only 3.3 minutes. We demonstrate that detection of only a few hundred photoelectrons within 100 μs is sufficient to distinguish a target event in a prototype system using ultraviolet LED excitation. Cytometric analysis of lanthanide labelled Giardia cysts achieved a signal-to-background ratio of two orders of magnitude. Results suggest that time-gated OSAM represents a new opportunity for high-throughput background-free biosensing applications

    High temperature deformation constitutive model of GGG70L duction iron

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    In order to accurately describe the high temperature deformation behavior of GGG70L ductile iron, the thermal simulation experiments with deformation rate of 0,01~10 s-1 were carried out at 800~1 100 °C by Gleeble-1500D thermal simulation machine. The deformation behavior of GGG70L ductile iron was studied. The temperature compensated strain rate Zener-Hollomon parameter was introduced, and the constitutive model of GGG70L ductile iron was established based on the strain compensated Arrhenius model. The results show that the theoretical value of peak stress calculated by the constitutive model is in good agreement with the experimental results, and the correlation is 97,8 %, which can accurately describe the high temperature deformation behavior of GGG70L ductile iro

    Theory of the thermoelectricity of intermetallic compounds with Ce or Yb ions

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    The thermoelectric properties of intermetallic compounds with Ce or Yb ions are explained by the single-impurity Anderson model which takes into account the crystal-field splitting of the 4{\it f} ground-state multiplet, and assumes a strong Coulomb repulsion which restricts the number of {\it f} electrons or {\it f} holes to nf1n_f\leq 1 for Ce and nfhole1n_f^{hole}\leq 1 for Yb ions. Using the non-crossing approximation and imposing the charge neutrality constraint on the local scattering problem at each temperature and pressure, the excitation spectrum and the transport coefficients of the model are obtained. The thermopower calculated in such a way exhibits all the characteristic features observed in Ce and Yb intermetallics. Calculating the effect of pressure on various characteristic energy scales of the model, we obtain the (T,p)(T,p) phase diagram which agrees with the experimental data on CeRu2_{2}Si2_2, CeCu2_{2}Si2_2, CePd2_{2}Si2_2, and similar compounds. The evolution of the thermopower and the electrical resistance as a function of temperature, pressure or doping is explained in terms of the crossovers between various fixed points of the model and the redistribution of the single-particle spectral weight within the Fermi window.Comment: 13 pages, 11 figure

    Machine Learning Interatomic Potentials as Emerging Tools for Materials Science.

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    Atomic-scale modeling and understanding of materials have made remarkable progress, but they are still fundamentally limited by the large computational cost of explicit electronic-structure methods such as density-functional theory. This Progress Report shows how machine learning (ML) is currently enabling a new degree of realism in materials modeling: by "learning" electronic-structure data, ML-based interatomic potentials give access to atomistic simulations that reach similar accuracy levels but are orders of magnitude faster. A brief introduction to the new tools is given, and then, applications to some select problems in materials science are highlighted: phase-change materials for memory devices; nanoparticle catalysts; and carbon-based electrodes for chemical sensing, supercapacitors, and batteries. It is hoped that the present work will inspire the development and wider use of ML-based interatomic potentials in diverse areas of materials research.Academy of Finland under project #310574. The authors are thankful for generous allocation of computational resources on the ARCHER UK National Supercomputing Service (EPSRC grants EP/K014560/1 and EP/P022596/1) and by CSC ‐ IT Center for Science, Finland, which supported some of the work discussed herein. V.L.D. and M.A.C. are grateful for mutual HPC‐Europa3 exchange visits (funded by the European Union's Horizon 2020 research and innovation programme under grant agreement No. 730897), during one of which this manuscript was finalized

    Conductance fluctuations at the integer quantum Hall plateau transition

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    We study numerically conductance fluctuations near the integer quantum Hall effect plateau transition. The system is presumed to be in a mesoscopic regime, with phase coherence length comparable to the system size. We focus on a two-terminal conductance G for square samples, considering both periodic and open boundary conditions transverse to the current. At the plateau transition, G is broadly distributed, with a distribution function close to uniform on the interval between zero and one in units of e^2/h. Our results are consistent with a recent experiment by Cobden and Kogan on a mesoscopic quantum Hall effect sample.Comment: minor changes, 5 pages LaTex, 7 postscript figures included using epsf; to be published Phys. Rev. B 55 (1997
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