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| Thesis Name：Protein Kinase C II Regulates Akt Phosphorylation on Ser-473 in a Cell Type- and Stimulus-specific Fashion |
| Country：[CN] |
Usage：[biochemistry] |
| Remarks： |
From the Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, California 92121, the National Institute of Vegetables, and Tea Science, NARO, 2769 Kanaya, Shizuoka 428-8501, Japan, the ¶Departments of Immunology and Pediatrics, University of Washington, School of Medicine, Seattle, Washington 98195, and the ||Departments of Pathology and Microbiology, New York University, School of Medicine, Howard Hughes Medical Institute, New York, New York 10016
Akt (= protein kinase B), a subfamily of the AGC serine/threonine kinases, plays critical roles in survival, proliferation, glucose metabolism, and other cellular functions. Akt activation requires the recruitment of the enzyme to the plasma membrane by interacting with membrane-bound lipid products of phosphatidylinositol 3-kinase. Membrane-bound Akt is then phosphorylated at two sites for its full activation; Thr-308 in the activation loop of the kinase domain is phosphorylated by 3-phosphoinositide-dependent kinase-1 (PDK1) and Ser-473 in the C-terminal hydrophobic motif by a putative kinase PDK2. The identity of PDK2 has been elusive. Here we present evidence that conventional isoforms of protein kinase C (PKC), particularly PKCII, can regulate Akt activity by directly phosphorylating Ser-473 in vitro and in IgE/antigen-stimulated mast cells. By contrast, PKC is not required for Ser-473 phosphorylation in mast cells stimulated with stem cell factor or interleukin-3, in serum-stimulated fibroblasts, or in antigen receptor-stimulated T or B lymphocytes. Therefore, PKCII appears to work as a cell type- and stimulus-specific PDK2.
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| Thesis Name：Nucleation and growth of CaCO3 crystals on PDAC/PSS self-assembled |
| Country：[CN] |
Usage：[Fabrication of biomimetic laminated] |
| Remarks： |
Fabrication of biomimetic laminated composite by mimicking the cyclical matrix control processes to form the highly structured Mollusca nacre is presented in this paper. (PDAC/PSS)n self-assembled multilayers were built-up through alternative absorption of polycation and polyanion to a substrate as matrices and their chemical structure were characterized by UV-Vis absorption spectra. And then the deposition of CaCO3 took place on the multilayers by dipping them into a supersaturated CaCO3 solution. The morphology and the structure of the CaCO3 crystals were characterized by SEM and X ray diffraction respectively. With (PDAC/PSS)15 the hexagonal crystals of CaCO3 with the pellet size of 10-20mm, which were very similar to the crystals existed in nacre, was obtained after 10 hr deposition. |
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| Thesis Name：Advances in Dictyostelium discoideum as an expression system |
| Country：[CN] |
Usage：[social amoeba of slime mould] |
| Remarks： |
Advances in genetic engineering have made possible the production of therapeutics and vaccines in the form of recombinant proteins for the treatment of many ailments like cancer, tumors, hypertension and AIDS. Construction of recombinant strains/cells using genetic technology and production of target proteins through cultivation of recombinant strains/cells have become increasing interested in modern biotechnology, which are widely used in production of heterologous proteins and metabolic engineering. At the current time frequently used expression host systems are prokaryotic bacterial system and eukaryotic yeast, insect, mammalian cells. However, these expression systems have different degrees of limitations for overexpression of eukaryotic genes.
In recent years, the single-celled amoeba of Dictyostelium discoideum(Dd) has emerged as a promising eukaryotic alternative system for the expression of recombinant proteins of high value[1]. In this article the advantages of Dd in comparison to other expression systems and advances in Dd for expression of heterologous proteins are reviewed. |
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| Thesis Name：A closed-shell coupled-cluster treatment of the Breit–Pauli first-order relativistic energy correction |
| Country：[CN] |
Usage：[ the two-component Breit–Pauli Hamiltonian] |
| Remarks： |
First-order relativistic corrections to the energy of closed-shell molecular systems are calculated, using all terms in the two-component Breit–Pauli Hamiltonian. In particular, we present the first implementation of the two-electron Breit orbit–orbit integrals, thus completing the first-order relativistic corrections within the two-component Pauli approximation. Calculations of these corrections are presented for a series of small and light molecules, at the Hartree–Fock and coupled-cluster levels of theory. Comparisons with four-component Dirac–Coulomb–Breit calculations demonstrate that the full Breit–Pauli energy corrections represent an accurate approximation to a fully relativistic treatment of such systems. The Breit interaction is dominated by the spin–spin interaction, the orbit–orbit interaction contributing only about 10% to the total two-electron relativistic correction in molecules consisting of light atoms. However, the relative importance of the orbit–orbit interaction increases with increasing nuclear charge, contributing more than 20% in H2S |
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| Thesis Name：Rapid screening of cinchona alkaloid derived phase-transfer catalysts. Application in the optimization of a glycine imine alkylation. |
| Country：[CN] |
Usage：[glycine imine alkylation] |
| Remarks： |
A method for the rapid screening of cinchona alkaloid
derived asymmetric phase transfer catalysts is discussed.
In this approach the catalysts are generated in situ via Nand
O- alkylation of the parent alkaloid, prior to
performing the reaction of interest. The whole sequence
can be performed using a parallel synthesizer with online
HPLC, thus enabling large numbers of catalysts to be
generated and assessed in an efficient manner.
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| Thesis Name：Iridium-catalyzed asymmetric hydrogenation |
| Country：[CN] |
Usage：[catalyze] |
| Remarks： |
Cationic iridium complexes with chiral P,N-ligands and
tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF) as
the counterion are efficient homogeneous catalysts for the
enantioselective hydrogenation of olefins. In contrast to
chiral rhodium- and ruthenium-phosphine catalysts, they
do not require the presence of a polar coordinating
group near the C=C bond. In the hydrogenation of
unfunctionalized aryl-substituted olefins, high
enantioselectivities of >95% ee with full conversion,
turnover numbers of up to 5000 and turnover frequencies
of >5000 h-1 have been achieved. As illustrated by the
examples given in Schemes 3 and 4, the application
range is largely complementary to chiral Rh and Ru
catalysts. Several types of functionalized and
unfunctionalized olefins, for which no suitable catalysts were previously available, can now be hydrogenated
with high efficiency and good to excellent enantioselectivity. The iridium complexes used as precatalysts are air-stable and easy to handle. Further
attractive features are the ready availability and the
modular nature of the chiral ligands, making it possible
to optimize the catalyst structure for a specific substrate.
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| Thesis Name：Reactivity of C10H and C10D with H2 and D2 |
| Country：[CN] |
Usage：[Experimental; Theoretical] |
| Remarks： |
We have investigated, both theoretically and experimentally, the reactions of naphthylium C10H and d-naphthylium C10D ions with H2 and D2. Cross sections as functions of the collision energy have been measured for a variety of reaction channels. Theoretical calculations have been carried out at the density functional theory level which utilizes the hybrid functional B3LYP and the split-valence 6-31G* basis set. The key features of the potential energy surfaces and the relevant thermochemical parameters have been calculated and they provide insights on the reaction mechanisms. The bimolecular reactivity of C10H with H2 is dominated by the production of naphthalene cation C10H. The reaction is not a direct atom-abstraction process, but instead it proceeds via the formation of a stable intermediate complex C10H of type geometry, with a significant mobility of hydrogen along the ring. This mobility allows the scrambling of the hydrogen atoms and causes the successive statistical fragmentation of the complex into a variety of product channels. Elimination of one H(D) atom appears to be favored over elimination of one H2 or HD molecule. Alternatively, the intermediate complex can be stabilized either by collision with a third body or by emission of a photon. ©2004 American Institute of Physics. |
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| Thesis Name：Highly Fluorescent, Water-Soluble, Size-Tunable Gold Quantum Dots |
| Country：[CN] |
Usage：[Method; Experimental] |
| Remarks： |
A new method to measure and analyze the time and spectrally resolved polarimetric response of magnetic materials is presented. It allows us to study the ultrafast magnetization dynamics of a CoPt3 ferromagnetic film. The analysis of the pump-induced rotation and ellipticity detected by a broad spectrum probe beam shows that magneto-optical signals predominantly reflect the spin dynamics in ferromagnets. |
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| Thesis Name：Highly Fluorescent, Water-Soluble, Size-Tunable Gold Quantum Dots |
| Country：[CN] |
Usage：[Experimental] |
| Remarks： |
Highly fluorescent, water-soluble, few-atom Au quantum dots have been created that behave as multielectron artificial atoms with discrete, size-tunable electronic transitions throughout the visible and near IR. Correlation of nanodot sizes with emission energies fits the simple relation, EFermi/N1/3, predicted by the jellium model. Providing the "missing link" between atomic and nanoparticle behavior in noble metals, these emissive, water-soluble Au nanoclusters open new opportunities for biological labels, energy transfer pairs, and light emitting sources in nanoscale optoelectronics. |
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| Thesis Name：Effect of Dipolar Interaction on the Antiferromagnetic Resonance Spectra of NiO |
| Country：[CN] |
Usage：[Experimental; Theoretical] |
| Remarks： |
We have investigated the antiferromagnetic (AF) resonance modes (AFMR) of NiO, theoretically using a model that includes the effects of exchange, dipolar coupling, and a small cubic anisotropy, and experimentally using Brillouin scattering. Using only superexchange between next nearest Ni atoms the model accounts for the observed AF structure with a [11] spin orientation. The model predicts that there are four, weakly coupled, AF lattices that should therefore exhibit eight AFMR modes. Because of degeneracies, only five distinct frequencies are predicted by the model. Three of these frequencies are consistent with the doublet observed by Raman scattering and the central peak reported in Brillouin experiments. Using Brillouin scattering we report the observation of the two missing modes. |
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