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111.
Chao Feng Zhang Li Fan Pin Yang 《中国化学快报》2007,18(1):97-98
Zinc may play a role as a co-factor in the pathogenesis of Alzheimer's disease(AD)through influencing the conformation and neurotoxicity of amyloidβ-protein(Aβ).Using the fluorescamine assay,we show for the first time that Zn~(2 )induced Aβ(10-21) aggregate in a concentration-dependent manner.These results indicate that Aβ(10-21)can be used as an in vitro model in Zn~(2 )- induced Aβaggregation and that the region 10-21 to be the minimal fragment of zinc-binding domain of full length Aβ(1-42). 相似文献
112.
Dong L Liu YC Tong YH Xiao ZY Zhang JY Lu YM Shen DZ Fan XW 《Journal of colloid and interface science》2005,283(2):380-384
Colloidal ZnO particles with narrow size distribution were prepared via a sol-gel process by base-catalyzed hydrolysis of zinc acetate. The morphology of ordered arrays of the particles was recorded by SEM. SEM also reveals that these uniform particles were composed of tiny ZnO subunits (singlets) sized of several nanometers. The size of the singlets, which is confirmed by X-ray diffraction and UV-vis absorption spectra, increases as the aging time is prolonged. The size-selective formation of colloids by aggregation of nanosized subunits is proposed to consist of two-stage growth by nucleation of nanosized crystalline primary particles and their subsequent aggregation into polycrystalline secondary colloids. The aggregates are all spherical because the internal rearrangement processes are fast enough. The ZnO colloids, i.e., the aggregates, tend to self-assemble into well-ordered hexagonal close-packed structures. Room-temperature photoluminescence was characterized for green and aged ZnO. 相似文献
113.
Biological events occurring at the implant-host interface, including protein adsorption are mainly influenced by surface properties of the implant. Titanium alloys, one of the most widely used implants, has shown good biocompatibility primarily through its surface oxide. In this study, a surface sol-gel process based on the surface reaction of metal alkoxides with a hydroxylated surface was used to prepare ultrathin titanium oxide (TiOx) coatings on silicon wafers. The oxide deposited on the surface was then modified by self-assembled monolayers (SAMs) of silanes with different functional groups. Interesting surface morphology trends and protein adhesion properties of the modified titanium oxide surfaces were observed as studied by non-specific protein binding of serum albumin. The surface properties were investigated systematically using water contact angle, ellipsometry, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) measurements. Results showed that the surface sol-gel process predominantly formed homogeneous, but rough and porous titanium oxide layers. The protein adsorption was dependent primarily on the silane chemistry, packing of the alkyl chains (extent of van der Waals interaction), morphology (porosity and roughness), and wettability of the sol-gel oxide. Comparison was made with a thermally evaporated TiOx-Ti/Si-wafer substrate (control). This method further extends the functionalization of surface sol-gel derived TiOx layers for possible titanium alloy bioimplant surface modification. 相似文献
114.
Using FcCOONa (Fc = (eta(5)-C(5)H(5))Fe(eta(5)-C(5)H(4))) as starting material, we obtained an unprecedented metal-organic coordination polymer containing ferrocenecarboxylate components [[Pb(2)(FcCOO)(eta(2)-FcCOO)(mu(2)-eta(2)-FcCOO)(mu(3)-eta(2)-FcCOO)(CH(3)OH)].1.5CH(3)OH.H(2)O](n) (1), tetramer [Zn(4)(mu(2)-FcCOO)(6)(mu(4)-O)] (2), and coordination polymers [Pb(FcCOO)(mu(2)-FcCOO)(bpe)](n) (3) (bpe = 1,2-bis(4-pyridyl)ethene), [[Zn(FcCOO)(2)(bpt)].2.5H(2)O](n) (4) (bpt = N,N'-bis(3-pyridylmethyl)thiourea), and [Zn(FcCOO)(eta(2)-FcCOO)(bbp)](n) (5) (bbp = 4,4'-trimethylene-dipyridine). Compounds 1 and 2 are formed by ferrocenecarboxylate units coordinating with Pb(II) or Zn(II). In polymer 1, ferrocenecarboxylate units have four kinds of coordinate modes; just these novel coordinate modes lead to the unprecedented one-dimensional polymer where two kinds of rhomboids are arranged alternatively along the chain. Compound 2 is a tetramer, in which a distinct connectivity of the six ferrocene units is established through the four Zn atoms. Compounds 3-5 are obtained by organic ligands bridging Pb(II) or Zn(II), leading to a new type of metal-organic coordination polymer. 相似文献
115.
Fan Caiyun Jia Hongmei Deuther-Conrad Winnie Brust Peter Steinbach J?rg Liu Boli 《中国科学B辑(英文版)》2006,49(2):169-176
A novel 99mTc labeled complex, [N-[2-((2-oxo-2-(4-(3-phenylpropyl)piperazin-1-yl)ethyl) (2-mercaptoethyl)amino)acetyl]-2-aminoethanethiolato]Technetium(V)
oxide (PPPE-MAMA’-99mTcO) ([
99m
Tc]-2) has been designed and prepared based on the integrated approach. The corresponding rhenium complex (PPPE-MAMA’-ReO)(Re-2) has been prepared and characterized. In vitro competition binding assays show moderate affinity of Re-2 towards σ1 and σ2 receptors with K
i values of 8.67 ± 0.07 and 5.71 ± 1.88 μmol, respectively. Planar images obtained at 0.5 h, 4 h, 20 h after i.v. injection
indicate the accumulation of [
99m
Tc]-2 in MCF-7 human breast tumor bearing mice at 20 h. Furthermore, the accumulation of [
99m
Tc]-2 has been inhibited at 20 h after co-injection of [
99m
Tc]-2 plus haloperidol (1 mg/kg). Biodistribution studies of [
99m
Tc]-2 display an in vivo tumor uptake of 0.14% ± 0.01% ID/g at 24 h post i.v. injection with a tumor/muscle ratio of 6.02 ± 0.87. The above results
suggest that [
99m
Tc]-2, derived from a previously published lead compound, retains certain tumor uptake and affinity for σ receptors. [
99m
Tc]-2 may be used as a basis for further structural modifications to develop tumor imaging agents with high affinity for σ receptors. 相似文献
116.
117.
Russian Chemical Bulletin - 相似文献
118.
The magnetic properties of a series of inorganic saturated rings, (SiH2)n, (GeH2)n, (NH)n, (PH)n, (AsH)n, On, Sn, and Sen (n = 3-6), exhibit zigzag behavior with ring size resembling that of aromatic and antiaromatic Hückel pi-systems and (CH2)n rings. Computed GIAO-SCF nucleus-independent chemical shifts (NICS) and localized (LMO) NICS analysis indicate that the sigma-ring electrons are chiefly responsible for this zigzag behavior. This evidence for sigma-aromaticity is further supported by theoretical strain energy (TSE). The Hückel 4n + 2/4n aromaticity/antiaromaticity rule for pi-electron systems applies well to the smaller saturated rings. 相似文献
119.
通过密度函数理论(DFT-DensityFunctionalTheory)对炭质吸附剂的孔径分布进行了表征。该法以多孔固体上N2吸附分子模型为依据,用一种方法对多孔固体的孔径分布从微孔到大孔范围进行确定。本文用该法对自制的聚丙烯腈活性炭纤维、国产煤质活性炭及日本产活性炭微球等六种炭质吸附剂的孔径分布进行了表征。 相似文献
120.
偏最小二乘光度法同时测定铜和铁的研究及应用 总被引:8,自引:0,他引:8
7-(1-苯偶氮)-8-羟基喹啉-5-磺酸钠在PH=4.75HAc-NaAc缓冲溶液中能与Cu(Ⅱ)和FE(Ⅲ)形成稳定的络合物,本文研究了Cu(Ⅱ)-PAHQS、Fe(Ⅲ)-PAHQS体系的显色条件,以偏最小二乘法处理两者重叠吸收峰,建立了光度法同时测定铜和铁的方法。 相似文献