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951.
An antifungal compound was isolated from the culture broth of Streptomyces koyangensis strain VK-A60 using various chromatographic procedures. On the basis of the high-resolution EI-mass and 1H and 13C NMR data, the compound was identified as 4-phenyl-3-butenoic acid. Colletotrichum orbiculare, Magnaporthe grisea, and Pythium ultimum were most sensitive to 4-phenyl-3-butenoic acid. Strong inhibitory effects of 4-phenyl-3-butenoic acid also were found against Pectobacterium carotovorum subsp. carotovorum and Ralstonia solanacearum. 4-Phenyl-3-butenoic acid effectively suppressed the development of M. grisea on rice leaves at the concentration of more than 10 microg/mL, and the protective activity was in general similar to that of the commercial fungicide tricyclazole. Treatment with 100 microg/mL of 4-phenyl-3-butenoic acid also effectively inhibited the anthracnose development on cucumber plants, although its in vivo efficacy was somewhat less effective than that of the commercial fungicide chlorothalonil. 相似文献
952.
953.
Dinneny JR Long TA Wang JY Jung JW Mace D Pointer S Barron C Brady SM Schiefelbein J Benfey PN 《Science (New York, N.Y.)》2008,320(5878):942-945
954.
A single-electron memory, in which a bit of information is stored by one electron, is demonstrated at room temperature. The memory is a floating gate metal-oxide-semiconductor transistor in silicon with a channel width ( approximately 10 nanometers) smaller than the Debye screening length of a single electron and a nanoscale polysilicon dot ( approximately 7 nanometers by 7 nanometers) as the floating gate embedded between the channel and the control gate. Storing one electron on the floating gate screens the entire channel from the potential on the control gate and leads to (i) a discrete shift in the threshold voltage, (ii) a staircase relation between the charging voltage and the shift, and (iii) a self-limiting charging process. The structure and fabrication of the memory should be compatible with future ultralarge-scale integrated circuits. 相似文献
955.
Requirement of AMPA receptor GluR2 phosphorylation for cerebellar long-term depression 总被引:1,自引:0,他引:1
Cerebellar long-term depression (LTD) is a model of synaptic memory that requires protein kinase C (PKC) activation and is expressed as a reduction in the number of postsynaptic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors. LTD was absent in cultured cerebellar Purkinje cells from mutant mice lacking the AMPA receptor GluR2 subunit and could be rescued by transient transfection with the wild-type GluR2 subunit. Transfection with a point mutant that eliminated PKC phosphorylation of Ser880 in the carboxy-terminal PDZ ligand of GluR2 failed to restore LTD. In contrast, transfection with a point mutant that mimicked phosphorylation at Ser880 occluded subsequent LTD. Thus, PKC phosphorylation of GluR2 Ser880 is a critical event in the induction of cerebellar LTD. 相似文献
956.
Aharonian F Akhperjanian AG Aye KM Bazer-Bachi AR Beilicke M Benbow W Berge D Berghaus P Bernlöhr K Boisson C Bolz O Borgmeier C Braun I Breitling F Brown AM Gordo JB Chadwick PM Chounet LM Cornils R Costamante L Degrange B Djannati-Ataï A Drury LO Dubus G Ergin T Espigat P Feinstein F Fleury P Fontaine G Funk S Gallant YA Giebels B Gillessen S Goret P Hadjichristidis C Hauser M Heinzelmann G Henri G Hermann G Hinton JA Hofmann W Holleran M Horns D de Jager OC Jung I Khélifi B Komin N 《Science (New York, N.Y.)》2005,307(5717):1938-1942
Very high energy gamma-rays probe the long-standing mystery of the origin of cosmic rays. Produced in the interactions of accelerated particles in astrophysical objects, they can be used to image cosmic particle accelerators. A first sensitive survey of the inner part of the Milky Way with the High Energy Stereoscopic System (HESS) reveals a population of eight previously unknown firmly detected sources of very high energy gamma-rays. At least two have no known radio or x-ray counterpart and may be representative of a new class of "dark" nucleonic cosmic ray sources. 相似文献
957.
Choi JS Kim JS Byun IS Lee DH Lee MJ Park BH Lee C Yoon D Cheong H Lee KH Son YW Park JY Salmeron M 《Science (New York, N.Y.)》2011,333(6042):607-610
Graphene produced by exfoliation has not been able to provide an ideal graphene with performance comparable to that predicted by theory, and structural and/or electronic defects have been proposed as one cause of reduced performance. We report the observation of domains on exfoliated monolayer graphene that differ by their friction characteristics, as measured by friction force microscopy. Angle-dependent scanning revealed friction anisotropy with a periodicity of 180° on each friction domain. The friction anisotropy decreased as the applied load increased. We propose that the domains arise from ripple distortions that give rise to anisotropic friction in each domain as a result of the anisotropic puckering of the graphene. 相似文献
958.
Three vat dyes have been applied to regular viscose rayon and their dyeing and wash fastness properties were evaluated. Particle
size determination was undertaken to obtain information about the size of dye particles converted by a reducing agent, to
see if dye particle size has an affect on dyeing properties of regular viscose rayon. It is observed that viscose rayon exhibits
more dyeability with reducing agent concentrations between 5–7.5 g/l. Also, we found that the vat dyeing system is greatly affected by the particle size of the vat dye converted to leuco form
by a reducing agent. 相似文献
959.
Temporarily solubilized azo disperse dyes based on 1,2-substituted indoles were synthesized and characterized. Dispersant-free
dyeing of polyester by using the synthesized dyes has been investigated. The colour yields of the dyes on the polyester fabric
were found to be highly dependent on the dyeing pH, optimum results being obtained at pH 5. The dyes exhibited good to excellent
fastness properties on polyester while lightfastness was moderate. 相似文献
960.
Jung?Jin?Lee Nam?Keun?Han Won?Jae?Lee Jae?Hong?Choi Jae?Pil?KimEmail author 《Fibers and Polymers》2002,3(3):85-90
Five temporarily solubilized reactive disperse dyes were synthesized and characterized. They were applied to polyester/cotton
blend fabric using one-bath dyeing method without dispersing agent. The dye that has azonaphthalene chromophore seemed to
not only be exhausted on polyester but also react with cotton. But other dyes were selectively dyed on polyester and showed
limited uptake on cotton. Good levelling as well as moderate to good colour fastness was obtained with the dyes on P/C blend
fabric. 相似文献