210 resultados para 7140-232


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研究虎眼万年青多糖对机体非特异性免疫和体液免疫功能的影响.方法:采用小鼠碳廓清单核巨噬细胞吞噬功能测定法筛选出虎眼万年青多糖中的有效组分,即60%醇浓度的虎眼万年青中性多糖(OCAPS3);采用溶血素测定方法研究不同剂量OCAPS3对小鼠抗体形成的影响.结果:OCAPS3能显著提高巨噬细胞的吞噬功能以及抗体生成的能力.结论:证明虎眼万年青多糖能有效地增强小鼠的非特异性免疫和体液免疫功能.

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用SiO2 为无机组份和以与SiO2 具有相似折射率和优良力学性能的丙烯酸类如甲基丙烯酸甲酯(MMA)和甲基丙烯酸羟乙酯 (HEMA) ,在交联剂 3 (三甲氧基硅 )丙基甲基丙烯酸酯 (MSMA)存在下 ,快速制备了两种杂化基质材料SiO2 /P(MMA MSMA)和SiO2 /P(HEMA MSMA)。分别以盐酸和六次甲基四胺作为酸性催化剂和碱性催化剂 ,建立了快速制备透明凝胶的两步溶胶 凝胶法 ,大大缩短了溶胶的成胶时间 ,所得杂化材料具有良好的光学透明性 ,利用此方法制备了掺杂稀土配合物的多种发光杂化材料。采用组装的方法 ,得到了稀土配合物与层状化合物α 磷酸氢锆 (α ZrP)及中孔分子筛材料MCM 4 1的组装体 ,并对所制备的杂化材料进行了表征。另外 ,将稀土配合物通过共价键嫁接于无机SiO2 基质中 ,得到了含有稀土配合物的分子杂化材料

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The rational synthesis and the structural and magnetic characterization of a nickel cluster are presented. The compound comprises a rhomblike Ni4O16 group encapsulated between two-heptadentate tungstoarsenate ligands [AsW9O34](9-). The crystal structure of K-10[Ni-4(H2O)(2)(AsW9O34)(2)](.)4H(2)O was solved in monoclinic, P2(1)/n symmetry, with a = 12.258(3) Angstrom, b = 21.232(4) Angstrom, c = 15.837(3) Angstrom, beta = 92.05(3)degrees, V = 4119.1(14) Angstrom(3), Z = 2, and R = 0.0862. The crystal structure of the Ni(II) derivative was compared with that of the Cu(II), Zn(II), Co(II) and Mn(II) derivatives. The Ni4O14(H2O)(2) unit in the compound shows no Jahn-Teller distortion. On the other hand, the Ni(II) derivative shows ferromagnetic exchange interactions within the Ni4O16 group (J = 7.8 cm(-1), J' = 13.7 cm(-1)) and an S = 4 ground state, the highest spin state reported in a heteropoly complex. Its redox electrochemistry has been studied in acid buffer solutions using cyclic voltammetry. It exhibited two steps of one-electron redox waves attributed to redox processes of the tungsten-oxo framework. The new catalyst showed an electrocatalytic effect on the reduction of NO2-.

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A functionalized high-density polyethylene (HDPE) with maleic anhydride (MAH) was prepared using a reactive extruding method. This copolymer was used as a compatibilizer of blends of polyamide 6 (PA6) and ultrahigh molecular weight polyethylene (UHMWPE). Morphologies were examined by a scanning electron microscope. It was found that the dimension of UHMWPE and HDPE domains in the PA6 matrix decreased dramatically, compared with that of the uncompatibilized blending system. The size of the UHMWPE domains was reduced from 35 mu m (PA6/UHMWPE, 80/20) to less than 4 mu m (PA6/UHMWPE/HDPE-g-MAH, 80/20/20). The tensile strength and Izod impact strength of PA6/UHMWPE/HDPE-g-MAH (80/20/20) were 1.5 and 1.6 times as high as those of PA6/UHMWPE: (80/20), respectively. This behavior could be attributed to chemical reactions between the anhydride groups of HDPE-g-MAH and the terminal amino groups of PA6 in PA6/UHMWPE/HDPE-g-MAH blends. Thermal analysis was performed to confirm that the above chemical reactions took place during the blending process. (C) 2000 John Wiley & Sons, Inc.

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Molecular dynamics (MD) simulations of a polyethersulfone (PES) chain are carried out in the amorphous state by using the Dreiding 2.21 force field at four temperatures. Two types of molecular motion, i.e, rotations of phenylene rings and torsions of large segments containing two oxygen atoms, two sulfur atoms, and five phenylene rings on the backbone, are simulated. The modeling results show that the successive phenylene rings should be in-phase cooperative rotations, whereas the successive large segments should be out-of-phase cooperative torsions. By calculating the diffusion coefficient for the phenylene ring rotations, it is found that this rotation contributes to the beta -transition of PES.

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The charactesistics of two-dimension spectra obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES) with charge injection detection (CID) in frequency domain were studied in the present paper. The measurement spectra were Fourier transformed and the frequency distribution of the spectra was obtained. Results showed that the spectra in frequency domain could he divided into two parts:high frequency and low frequency signals. The later stood for measurement spectra and the former for background and noises. However, the high frequecny signals could not be smoothed simply to reduce noises because the background was deteriorated even though the spectral signal did not change significantly.

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本文对电感耦合等离子体原子发射光谱分析 (ICP AES)中电荷注入检测器 (CID)得到的二维光谱的频率特性作了研究。测量光谱经过傅里叶变换得到其光谱的频域分布。结果表明 ,测量光谱在频域中的信号可被分为两部分 :即低频信号和高频信号。前者代表有用的分析信号而后者代表背景和噪声。然而 ,不能采用简单滤除高频信号的方法来去除噪声 ,因为这样虽然高频信号没有明显改变但会使背景变形。

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通过微机技术与仪器改造技术相结合,探索了色散型光谱仪更新的新途径。以IBM微机为主系统,微机扫描控制器(MSC)为从系统,由RS-232串行通信口连接,以对话方式通讯、协议、交换信息。MSC的使用使系统具备了通用性和灵活性,在色散性光谱仪功能开发上具有广泛应用前景。该系统适用于红外、紫外、可见等色散型光谱仪。原机的测光系统与机械系统基本不变,由于增加了光谱数据处理能力,提高了光谱仪的使用性能。

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(Li.3DME)[eta(5)-C5H5)3NdC6H5], 1 was synthesized by the reaction of NdCl3.2LiCl, 2 equivalents of cyclopentadienylsodium and one equivalent of phenyllithium in THF at -78-degrees-C, and crystallized from THF and DME. The crystal structure of 1 was determined by X-ray diffraction method at -80-degrees-C. The crystal of 1 is triclinic, space group P1BAR with a = 15.752(6), b = 16.232(3), c = 23.038(7) angstrom, alpha = 108.81(2), beta = 93.31(3), gamma = 108.38(2)-degrees, Z = 6 and D = 1.33 g/cm3. Least-squares refinement (5732 observed reflections) led to a final R of 0.053. The complex consists of disconnected ion pairs of (Li.3DME)+ and [(eta(5)-C5H5)3NdC6H5]-. The neodymium atom was connected to three eta(5)-bonded cyclopentadienyls and one sigma-bonded phenyl in a distorted tetrahedral arrangement with Nd-C(sigma-) 2.593(17), 2.613(13) and 2.601(13) angstrom.

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Ferritins are conserved Iron storage proteins that exist in most living organisms and play an essential role in Iron homeostasis. In this study, we reported the identification and analysis a ferritin M subunit, SmFerM, from turbot Scophthalmus maximus. The full length cDNA of SmFerM contains a 5'-untranslated region (UTR) of 232 bp, an open reading frame (ORF) of 531 bp, and a 3'-UTR of 196 bp The ORF encodes a putative protein of 176 amino acids, which shares extensive sequence identities with the M terrains of several fish species. In silico analysis identified in SmFerM both the ferroxidase center of mammalian H ferritins and the iron nucleation site of mammalian L ferritins. Quantitative real time reverse transcriptase-PCR analysis indicated that SmFerM expression was highest in muscle and lowest in heart and responded positively to experimental challenges with bacterial pathogens and poly(I center dot C) Exposure of cultured turbot hepatocytes to treatment of stress inducers (iron, copper, and H2O2) significantly upregulated the expression of SmFerM in a dose dependent manner. Iron chelating analysis showed that recombinant SmFerM purified from Escherichia coli exhibited apparent iron binding activity. These results suggest that SmFerM is a functional M ferritin and is likely to play a role in iron sequestration and protection against oxidative stress and microbial infection (C) 2010 Elsevier Inc All rights reserved

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Sediment samples were collected from the lower channel of the Yangtze River and the Yellow River and the contents of rare earth elements (REEs) were measured. In addition, some historical REEs data were collected from published literatures. Based on the delta Eu-N-I REEs pound plot, a clear boundary was found between the sediments from the two rivers. The boundary can be described as an orthogonal polynomial equation by ordinary linear regression with sediments from the Yangtze River located above the curve and sediments from the Yellow River located below the curve. To validate this method, the REEs contents of sediments collected from the estuaries of the Yangtze River and the Yellow River were measured. In addition, the REEs data of sediment Core 255 from the Yangtze River and Core YA01 from the Yellow River were collected. Results show that the samples from the Yangtze River estuary and Core 255 almost are above the curve and most samples from the Yellow River estuary and Core YA01 are below the curve in the delta Eu-N-I REEs pound plot. The plot and the regression equation can be used to distinguish sediments from the Yangtze River and the Yellow River intuitively and quantitatively, and to trace the sediment provenance of the eastern seas of China. The difference between the sediments from two rivers in the delta Eu-N-I REEs pound plot is caused by different mineral compositions and regional climate patterns of the source areas. The relationship between delta Eu-N and I REEs pound is changed little during the transport from the source area to the river, and from river to the sea. Thus the original information on mineral compositions and climate of the source area was preserved.

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The geochemical and U-series isotopic characteristics of hydrothermal sulfide samples from the Jade site (127A degrees 04.5'E, 27A degrees 15'N, water depth 1300-1450 m) at Jade site in the Okinawa Trough were analyzed. In the hydrothermal sulfide samples bearing sulfate (samples HOK1 and HOK2), the LREEs are relatively enriched. All the hydrothermal sulfide samples except HOK1 belong to Zn-rich hydrothermal sulfide. In comparison with Zn-rich hydrothermal sulfides from other fields, the contents of Zn, Pb, Ag, Cd, Au and Hg are higher, the contents of Fe, Al, Cr, Co, Ni, Sr, Te, Cs, Ti and U lower, and the Pb-210 radioactivity ratios and Pb-210/Pb ratios very low. In the hydrothermal sulfide mainly composed of sphalerite, the correlations between rare elements Hf and U, and Hf and Mn as well as that between dispersive elements Ga and Zn, are strongly positive; also the contents of Au and Ag are related to Fe-sulfide, because the low temperature promotes enrichment of Au and Ag. Meanwhile, the positive correlations between Fe and Bi and between Zn and Cd are not affected by the change of mineral assemblage. Based on the Pb-210/Pb ratios of hydrothermal sulfide samples (3.99x10(-5)-5.42x10(-5)), their U isotopic composition (U-238 content 1.15-2.53 ppm, U-238 activity 1.07-1.87 dpm/g, U-234 activity 1.15-2.09 dpm/g and U-234/U-238 ratio 1.07-1.14) and their Th-232 and Th-230 contents are at base level, and the chronological age of hydrothermal sulfide at Jade site in the Okinawa Trough is between 200 and 2000 yr.

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长期、定点、连续测量海洋环境参数,尤其是从海洋表面到海底的垂直剖面的监测一直以来大都是由船只完成,耗费大量的人力和财力。“海浪驱动自持式海洋要素垂直剖面测量系统”(简称“海马”)利用海洋无时不在的波浪能,驱动滑行器单方向下潜运动,直达海底或程序设定的预定深度,在控制系统作用下,滑行器依靠自身的浮力匀速上浮, 并在此过程中,完成海洋要素的自动测量和存储。 当今海洋仪器大多采用“闪存”来存储数据,主要有RS-232串口和并型口的CF(Compact Flash)卡两种形式。但是两种接口都有一定的缺陷:CF卡不能和PC机直接通信,必须通过转接口才能将数据传送到PC机上;而RS-232接口虽然可以和PC机直接通信,但是由于其传输速度较慢,不利于大量数据的传输。由于上述两种接口的缺点,“海马”采用U盘来实现数据的存储。 USB接口不仅可以和PC机直接通信,而且具有使用方便,数据传输率高,又支持即插即用等特点,但由于USB接口协议复杂,涉及的方面广,特别是软件种类比较多,而且USB芯片种类繁多,使得USB设备的开发非常困难。 本文设计的USB(Universal Serial Bus)接口电路以单片机AT89C51以及CYPRESS公司生产的USB接口芯片SL811HS为核心,结合了随机存储芯片HY62256以及看门狗芯片X25165。在介绍了SL811HS控制器芯片的主要特点的基础上,重点阐述了利用这一芯片在C语言的编程控制之下如何识别U盘的插入和拔出,以及如何将单片机的数据按协议规定写入U盘,其中的协议包括FAT文件协议,USB协议和UFI命令协议。 本系统实现了单片机对U盘的数据存储,速度快,存储容量大,数据读取方便,直观明了,系统工作安全可靠,抗干扰能力强,可扩展性大,而且针对下位机设计的串口协议简单,可以满足“海马”海量数据的存储要求。