98 resultados para 603
Resumo:
A novel organic-inorganic hybrid complex [(CuCl)(2) (o-phen)](infinity) 1 (o-phen = o-phenanthroline) has been hydrothermally synthesized and structurally characterized by elemental analyses, XPS spectrum, TG analysis, and single-crystal X-ray diffraction. Compound I crystallizes in the monoclinic system, space group P2(1)/n, a = 3.7285(7) Angstrom, b = 19.603(4) Angstrom, c = 16.757(3) Angstrom, beta = 95.83(3)degrees, V = 1218.4(4) Angstrom(3), Z = 4, lambda(MoKalpha) = 0.71073 Angstrom (R(F) = 0.0643 for 2559 reflections). Data were collected on an R-axis RAPID diffractometer at 293 K in the range of 1.60 < θ < 27.48degrees. The title compound exhibits a one-dimensional chain-like scaffolding constructed by the unusual [Cu3Cl3] hexagon motifs by, sharing opposite edges. Only Cu(1) sites of the [Cu3Cl3] hexagon are coordinated with N donors of o-phen groups. Furthermore, the three-dimensional supermolecular architecture is formed by C-H...Cl hydrogen bonds between o-phen groups and CuCl chains.
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A surface emitting microcavity was formed by sandwiching a polymer film containing PVK, Alq(3) and DCM between a distributed Bragg reflector (DBR) with a reflectivity of 99% and a silver film (300 nm). The lasing phenomenon was observed in DCM-doped PVK microcavity. The full width at half maximum (FWHM) was 0.6 nm with the peak wavelength at 603 nm. The threshold energy for lasing was estimated to be about 2.5 mu J per pulse. (C) 2000 Published by Elsevier Science S.A. All rights reserved.
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An octadecanethiol monolayer was formed on an aqueous gold sols subphase, it's LB films were characterized by means of pi-A isotherms, TEM (transmission electron microscopy), XRD (X-ray diffraction) and UV-Vis spectroscopy. (C) 1998 Elsevier Science Limited. All rights reserved.
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A series of rare earth (Gd, Eu, Tb) complexes with different substituent group carboxylic acids (ortho-hydroxylbenzioc acid, ortho-aminobenzoic acid and ortho-methoxy benzoic acid) and 1,10-phenanthroline were synthesized. The spectroscopic studies of the photophysical properties such as luminescence properties, energy match and intramolecular energy transfer were carried out. The lowest triplet state energies of ligands and the intramolecular energy transfer efficiencies were determined with the measurement of low phosphorescence spectra and lifetimes of Gd complexes.
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评述了近年来我国学者对萃取色谱分离稀土元素各种体系的研究及其在高纯稀土 分离方面的应用,并对高纯稀土制备的发展方向进行了展望。
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An assay procedure utilizing pulsed amperometric detection at a platinum-particles modified electrode has been developed for the determination of cysteine and glutathione in blood samples following preliminary separation by reversed-phase liquid chromatography. A chemically modified electrode (CME) constructed by unique electroreduction from a platinum-salt solution to produce dispersed Pt particles on a glassy carbon surface was demonstrated to catalyze the electo-oxidation of sulfhydryl-containing compounds: DL-cysteine (CYS), reduced glutathione (GSH). When used as the sensing electrode in flow-system pulsed-amperometric detection (PAD), electrode fouling could be avoided using a waveform in which the cathodic reactivation process occurred at a potential of - 1.0 V vs. Ag/AgCl to achieve a cathodic desorption of atomic sulfur. A superior detection limit for these free thiols was obtained at a Pt particle-based GC electrode compared with other methods; this novel dispersed Pt particles CME exhibited high electrocatalytic stability and activity when it was employed as an electrochemical detector in FIA and HPLC for the determination of those organo-sulfur compounds.
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Ca4Y6(SiO4)(6)O:A (A = Pb2+, Eu3+, Tb3+, Dy3+) phosphors have been prepared by two methods: the sol-gel method and the conventional dry method. The crystallization processes and the luminescence characteristics of the phosphors were studied, The sol-gel method features low-temperature formation of the phosphor, leading to successful preparation of Pb2+-activated phosphors which could not be prepared by the dry method at high temperature. The (4f)(8-)(4f)(7)(5d)(1) absorption band of Tb3+ and the charge-transfer (CT) band of Eu3+ have higher energies and narrower half-widths in the sol-gel-derived phosphors than in the phosphors prepared by the dry method, respectively. The Tb3+ and Dy3+ ions show stronger emission in the former than in the latter. Both the yellow-to-blue intensity ratio (Y:B) of Dy3+ and the red-to-orange intensity ratio (R:O) of Eu3+ in the sol-gel-derived phosphors are smaller than those for the phosphors derived by the dry method.
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本研究以低硒和维生素E(VE)的克山病病区粮饲养大鼠,用放免法测定其血浆和心肌的内皮素(ET),发现克山病病区组ET水平明显高于其它各组;同时伴有谷胱甘肽过氧化物酶(GSH-Px)活力下降,自由基净含量和脂质过氧化物(LPO)浓度增高。ET升高和GSH-Px活力呈负相关,和自由基净含量、LPO浓度呈正相关。结果提示:ET水平的变化可能作为一种中间环节参与克山病的发病机制;ET升高可能是使克山病的心肌坏死具有缺血缺氧特征的一个重要因素;硒和VE不仅可以改善心肌自由基代谢紊乱状态,而且很可能通过由自由基和LPO或其它尚未知的环节影响ET的水平。
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AB交联共聚物(ABCP)和互穿网络聚合物(IPN)都属交联网状聚合物,只是前者形成一个网络,后者构成两个独立网络(图1),因此两者的性能有明显差别,特别是相容性。目前对ABCP的研究主要是聚酯,聚醚体系,本工作选用便宜的蓖麻油聚氨酯(COPU)和MMA为原料,合成ABCP,得到具有阻尼性能的材料。
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A total of 45 microsatellite loci from yellow perch, Perca flavescens, were isolated and characterized. Among the 45 microsatellite loci, 32 had more than two alleles. A wild population of P. flavescens (n = 48) was used to examine the allele range of the microsatellite loci. Mendelian inheritance of alleles was confirmed by examining the amplified products in pair-mated families. The number of alleles for the 32 polymorphic loci varied from two to 16, and observed heterozygosity ranged between 0.024 (YP79) and 0.979 (YP60). Cross-species polymorphic amplification in four other Percidae species was successful for 22 loci.
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Lysozyme is a widely distributed hydrolase possessing lytic activity against bacterial peptidoglycan, which enables it to protect the host against pathogenic infection. In the present study, the cDNA of an invertebrate goose-type lysozyme (designated CFLysG) was cloned from Zhikong scallop Chlamys farreri by expressed sequence tag (EST) and rapid amplification of cDNA ends (RACE) techniques. The full-length cDNA of CFLysG consisted of 829 nucleotides with a canonical polyadenylation signal sequence AATAAA and a poly(A) tail, and an open reading frame (ORF) of 603 bp encoding a polypeptide of 200 amino acid residues with a predicted molecular weight of 21.92 kDa and theoretical isoelectric point of 7.76. The high similarity of CFLysG with goose-type (g-type) lysozymes in vertebrate indicated that CFLysG should be an invertebrate counterpart of g-type lysozyme family, which suggested that the origin of g-type lysozyme preceded the emergence of urochordates and even preceded the emergence of deuterostomes. Similar to most g-type lysozymes, CFLysG possessed all conserved features critical for the fundamental structure and function of g-type lysozymes, such as three catalytic residues (Glu 82, Asp 97, Asp 108). By Northern blot analysis, mRNA transcript of CFLysG was found to be most abundantly expressed in the tissues of gills, hepatopancreas and gonad, weakly expressed in the tissues of haemocytes and mantle, while undetectable in the adductor muscle. These results suggested that CFLysG could possess combined features of both the immune and digestive adaptive lysozymes. To gain insight into the in vitro lytic activities of CFLysG, the mature peptide coding region was cloned into Pichia pastoris for heterogeneous expression. Recombinant CFLysG showed inhibitive effect on the growth of both Gram-positive and Gram-negative bacteria with more potent activities against Gram-positive bacteria, which indicated the involvement of CFLysG in the innate immunity of C. farreri. (c) 2006 Elsevier Ltd. All rights reserved.
A broad deglacial delta C-13 minimum event in planktonic foraminiferal records in the Okinawa Trough
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The equatorial Pacific upwelling zone has been suspected of playing an important role in the global atmospheric CO2 changes associated with glacial-interglacial cycles. In order to assess the influencing scope of the surface water deglacial delta(13)C minimum in the tropical low-latitude Pacific, the core DGKS9603, collected from the middle Okinawa Trough, was examined for 4513 C records of planktonic foraminifera N. dutertrei and G. ruber. The planktonic foraminiferal delta(13)C records show a clear decreasing event from 20 to 6 cal. kaBP., which is characterized by long duration of about 14 ka and amplitude shift of 0.4 x 10(-3). Its minimum value occurred at 15.7 cal kaBP. The event shows fairly synchrony with the surface water deglacial delta(13)C minimum identified in the tropical Pacific and its marginal seas. Because there is no evidence in planktonic foraminiferal fauna and 45180 records for upwelling and river runoff enhancement, the broad deglacial delta(13)C minimum event in planktonic foraminiferal records revealed in core DGKS9603 might have been the direct influencing result of the deglacial surface water of the tropical Pacific. The identification for the event in the Okinawa Trough provides new evidence that the water evolution in the tropical low-latitude Pacific plays a key role in large regional, even global carbon cycle.
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鱼类胚胎由于其自身结构特征:体积大、含水量高、多室结构等,迄今超低温保存尚未成功。超低温保存过程中所造成的冷冻损伤是制约鱼类胚胎超低温保存成功与否的关键,具体表现为渗透压影响、抗冻剂毒性、冰晶损伤等。系统研究并阐明鱼类胚胎冷冻损伤机理,是成功建立鱼类胚胎超低温保存技术的基础。本论文主要针对胚胎对渗透压的耐受性、抗冻剂对胚胎的渗透性、降温速率对胚胎内外冰晶形成温度的影响等冷冻损伤机理进行了系统研究,主要研究结果如下: 1.通过检测胚胎在不同浓度人工海水(0%、25%、50%、75%、1×、2×、3×、4×,渗透压范围0~3740 mOsm/kg)中的孵化率,确定了真鲷不同发育时期胚胎对渗透压的耐受范围,以及心跳期胚胎浸泡不同时间对渗透压的耐受范围。结果显示:①真鲷2-4细胞期、原肠期、10-14体节期胚胎、心跳期和出膜前期胚胎孵化率>50%时渗透压的范围依次为:919~1391 mOsm/kg、919~1391 mOsm/kg、462 ~1391 mOsm/kg、232~1878 mOsm/kg和692~1391 mOsm/kg,表明心跳期胚胎对渗透压变化的耐受范围最广;②在不同浓度人工海水中分别浸泡10 min、30 min、1 h、5 h和10 h后,真鲷胚胎孵化率无显著变化的渗透压范围分别为0~2804 mOsm/kg、0~1878 mOsm/kg、232~1391 mOsm/kg、232~1391 mOsm/kg和919~1391 mOsm/kg;结果表明心跳期胚胎对渗透压的耐受范围随浸泡时间的延长而减小。 2.采用毛细管电泳技术检测胚胎内部DMSO的浓度,并且分析了胚胎孵化率和胚胎内部DMSO的浓度随浸泡时间变化与外部抗冻剂的关系。结果表明胚胎孵化率随胚胎外部抗冻剂溶液浓度和浸泡时间的增加而降低;胚胎内部DMSO浓度随胚胎外部抗冻剂溶液浓度和浸泡时间的增加而增加。对胚胎孵化率(y1)随抗冻剂溶液浓度(x)的变化进行一元三次多项式回归,当浸泡时间分别为10 min、30 min和60 min时,回归方程依次为:y1 = -2832.7x3 + 575.01x2 - 37.011x + 99.641(R2 = 0.9722);y1 = 30288x3 - 16322x2 + 2077.3x + 27.603(R2 = 0.9876);y1 = 16052x3 - 5985.2x2 - 32.696x + 119.6(R2 = 0.9124)。对胚胎内部DMSO浓度(y2)随抗冻剂溶液浓度(x)的变化进行回归,当浸泡时间分别为10 min、30 min和60 min时,回归方程依次为:y2 = 0.2584e6.7294x(R2 = 0.9876);y2 = 0.2521e10.964x(R2 = 0.9644);y2 = 0.4054e10.95x(R2 = 0.8954)。 3. 利用低温显微镜观察了不同降温速率(20、40、60、80、100、120℃/min)对胚胎内外冰晶形成温度的影响。胚胎外部冰晶形成温度(TEIF)随降温速率的增加显著下降,在降温速率大于80℃/min之后,TEIF随降温速率增加而降低的幅度减小;胚胎内部冰晶形成温度(TIIF)在降温速率小于80℃/min 时随降温速率的升高而降低,在降温速率大于80℃/min 时随降温速率的升高而升高;胚胎内外冰晶形成温度差值(TEIF - TIIF)在降温速率小于80℃/min时随降温速率的升高而增大,在降温速率大于80℃/min时随降温速率的升高而减小。 4. 在低温显微镜下观察了真鲷胚胎低温保存中有复活胚胎记录的保存方法在冷冻解冻过程中的冰晶形成过程,结果表明:①在冷冻过程中,玻璃化法冷冻的胚胎的内部冰晶形成温度(-53.70,-64.33℃)显著低于程序降温法(-17.51,-21.40℃);而且在玻璃化法冷冻的胚胎内部冰晶形成温度高于外部冰晶后形成(-70.30℃),程序降温法中则相反,胚胎内部冰晶形成温度显著低于外部冰晶形成温度(-4.93,-5.00℃);玻璃化法中,40%PG冷冻的胚胎外部溶液出现玻璃化现象,其他组均未出现;②在解冻过程中,各组均出现重结晶现象;解冻后,玻璃化法的胚胎完整率(62.82%)远高于程序降温法(9.21%)。
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巴颜喀拉山地区位于青海省南部,北纬32°20′~35°15′,东经94°50′~101°45′,面积约84 000km2,海拔高程介于3 600m至5 369m之间.本地区拥有种子植物1 116种,分属于64科,295属.区系特征概述如下:1)对属的分布区类型的分析表明,本地区植物区系以北温带成分为主,仅有9个分布区从热带延伸到温带的热带属,且在本区所含种类极少或仅有1种.2)对种的分布区类型的分析表明,大多数种(不包括中国特有种)属于中亚成分和东亚成分,且多呈中亚-喜马拉雅-中国西南或中国-喜马拉雅分布式样.以此为据所得结论是,本地区的种以温带成分为优势,具高原、高山分布的特点.3)本区东南部的生态环境和区系成分的来源均不同于其余地区.东亚分布型及其变型中国-喜马拉雅的种聚集在东南部.这里被认为是那些来源于横断山和西秦岭的区系成分的一个通道.4)对中国特有种的分析表明,本区系与横断山区系和甘肃南部区系联系最为密切.5)在高山特化作用和高山生态因子的选择之下,本区植物获得了适应寒冷和干旱的特性.6)本区植物的耐寒性常常伴随着耐旱和耐湿的双重特性,植物的这些特性也反映在它们的地理分布上.7)本区的区系性质和特点与唐古特地区基本一致,因此本植物区系应视为唐古特区系的一部分.