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991.
992.
Tropomyosin-related kinase A (TrkA) plays an important role in cell survival, differentiation, and apoptosis in various neuronal and nonneuronal cell types. Here we show that TrkA overexpression by the Tet-On system mimics NGF-mediated activation pathways in the absence of nerve growth factor (NGF) stimulation in U2OS cells. In addition, p53 upregulation upon DNA damage was inhibited by TrkA, and p21 was upregulated by TrkA in a p53-independent manner. TrkA overexpression caused cell death by interrupting cell cycle progression, and TrkA-induced cell death was diminished in the presence of its specific inhibitor GW441756. Interestingly, TrkA-mediated cell death was strongly related to gammaH2AX production and poly (ADP-ribose) polymerase cleavage in the absence of DNA damage inducer. In this study, we also reveal that gammaH2AX production by TrkA is blocked by TrkA kinase inhibitors K-252a and GW441756, and it is also significantly inhibited by JNK inhibitor SP600125. Moreover, reduction of cell viability by TrkA was strongly suppressed by SP600125 treatment, suggesting a critical role of JNK in TrkA-induced cell death. We also found that gammaH2AX and TrkA were colocalized in cytosol in the absence of DNA damage, and the nuclear localization of gammaH2AX induced by DNA damage was partly altered to cytosol by TrkA overexpression. Our results suggest that the abnormal cytosolic accumulation of gammaH2AX is implicated in TrkA-induced cell death in the absence of DNA damage. 相似文献
993.
The reaction of enantiomerically pure 2-substituted 1-phenylethyl-aziridine with methyl trifluoromethanesulfonate generated a stable methylaziridinium ion, which was reacted with various external nucleophiles, including nitrile, to yield synthetically valuable and optically pure acyclic amine derivatives in a completely regio- and stereoselective manner. 相似文献
994.
Poly(vinyl acetate)-b-polystyrene, poly(vinyl acetate)-b-poly(methyl acrylate) and poly(vinyl acetate)-b-poly(methyl methacrylate) block copolymers with low polydispersity (M(w)/M(n) < 1.25) were prepared by successive reversible addition-fragmentation chain transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP) employing a bromoxanthate iniferter (initiator-transfer agent-terminator). 相似文献
995.
We have investigated binder-free Co(OH)2-combined carbon-nanotube (CNT) array electrodes using anodized aluminum oxide (AAO) templates for micro-electrochemical capacitors. It is shown that compared to the capacitors fabricated with CNT only electrodes (6.3 F/cm3 at 100 mV/s), those with the Co(OH)2-combined CNT array electrodes produce much higher capacitance (12.74 F/cm3 at 100 mV/s) together with superior high-rate capacitance. The improved electrochemical behavior is explained in terms of high capacitance of amorphous Co(OH)2 electrode and the use of CNT arrays as effective current collector. 相似文献
996.
Chol‐Won Koh U‐Hwang Lee Dr. June‐Kyu Song Hae‐Rim Lee Min‐Hye Kim Myungkoo Suh Dr. Young‐Uk Kwon Prof. Dr. 《化学:亚洲杂志》2008,3(5):862-867
We report the preparation of mesoporous titania thin films with the R m pore structure derived from the Im m self‐assembled ordering of the titania species and an EO106PO70EO106 triblock copolymer. The films were spin‐cast and then aged at 18 °C at a relative humidity of 70 %, which led to the orientation of the Im m structure with the [111] direction perpendicular to the substrates. The [111] body‐diagonal channels became vertical channels upon calcination at 400 °C, thus leading to thin films with vertical channels. The pores are ordered over a large area of up to 1 μm2. The titania films can be formed on various types of substrates. By using a titania film formed on a Pt‐coated Si wafer as a template, we produced by an electrochemical‐deposition technique arrays of gold nanowires, whose morphology suggests that most of the pores of the titania thin films are accessible. The pore structure of vertical channels is stable up to 600 °C, at which temperature the wall materials crystallize into anatase. 相似文献
997.
Let X be a non-degenerate, not necessarily linearly normal projective variety in . Recently the generalization of property N
p
to non-linearly normal projective varieties have been considered and its algebraic and geometric properties are studied extensively.
One of the generalizations is the property N
d,p
for the saturated ideal I
X
(Eisenbud et al. in Compos Math 141: 1460–1478, 2005) and the other is the property for the graded module of the twisted global sections of (Kwak and Park in J Reine Angew Math 582: 87–105, 2005). In this paper, we are interested in the algebraic and geometric
meaning of properties for every p ≥ 0 and the syzygetic behaviors of isomorphic projections and hyperplane sections of a given variety with property .
Youngook Choi and Sijong Kwak were supported in part by KRF (grant No. 2005-070-C00005). 相似文献
998.
999.
We describe for the first time an impulsive, electropulsation-driven backflow in microchannels for on-chip cell electroporation. 相似文献
1000.
Kim S Chung JK Kwak K Bowman SE Bren KL Bagchi B Fayer MD 《The journal of physical chemistry. B》2008,112(32):10054-10063
Unfolded vs native CO-coordinated horse heart cytochrome c (h-cyt c) and a heme axial methionine mutant cyt c552 from Hydrogenobacter thermophilus ( Ht-M61A) are studied by IR absorption spectroscopy and ultrafast 2D-IR vibrational echo spectroscopy of the CO stretching mode. The unfolding is induced by guanidinium hydrochloride (GuHCl). The CO IR absorption spectra for both h-cyt c and Ht-M61A shift to the red as the GuHCl concentration is increased through the concentration region over which unfolding occurs. The spectra for the unfolded state are substantially broader than the spectra for the native proteins. A plot of the CO peak position vs GuHCl concentration produces a sigmoidal curve that overlays the concentration-dependent circular dichroism (CD) data of the CO-coordinated forms of both Ht-M61A and h-cyt c within experimental error. The coincidence of the CO peak shift curve with the CD curves demonstrates that the CO vibrational frequency is sensitive to the structural changes induced by the denaturant. 2D-IR vibrational echo experiments are performed on native Ht-M61A and on the protein in low- and high-concentration GuHCl solutions. The 2D-IR vibrational echo is sensitive to the global protein structural dynamics on time scales from subpicosecond to greater than 100 ps through the change in the shape of the 2D spectrum with time (spectral diffusion). At the high GuHCl concentration (5.1 M), at which Ht-M61A is essentially fully denatured as judged by CD, a very large reduction in dynamics is observed compared to the native protein within the approximately 100 ps time window of the experiment. The results suggest the denatured protein may be in a glassy-like state involving hydrophobic collapse around the heme. 相似文献