α-B-Keggin型杂多化合物K_5H[Co_4(VW_9O_(33))_2]·5H_2O的合成和结构

合成了新化合物K_5H[Co_4(VW_9O_(33))·5H_2O,并运用IR,UV-ViS,DTA和单晶X射线衍射对其结构进行了表征.测定结果证实标题化合物具有α-B-Keggin型结构,两个(VW_9O_(33)~(7-)结构单元由四个Co(Ⅱ)O_6 八面体连接.杂多化合物属单斜晶系P2_(1/n),a=1.2307(3)nm,b=2.1250(4)nm,c=1.5817(3)nm,β=91.86(3)°,V=4.1343(14)nm~3,R=0.0895,R_w=0.2180.

Polymerization of ethylene by zirconocene-B(C6F5)(3) catalysts with aluminum compounds

Ethylene polymerization by zirconocene-B(C6F5)(3) catalysts with various aluminum compounds has been investigated. It is found that the catalytic activity depended on zirconocenes used, and especially on the type of aluminum compounds. For Et(H(4)Ind)(2)ZrCl2 (H(4)Ind : tetrahydroindenyl), the activity decreases in the following order: Me3Al > i-Bu3Al > Et3Al much greater than Et2AlCl. While for Cp2ZrCl2(Cp : cyclopentadienyl), it varies as follows: i-Bu3Al > Me3Al much greater than Et3Al. Furthermore, the activity is significantly affected by the addition mode of the catalytic components, which may imply that the formation of active centers is associated with an existing concentration of catalytic components. Results of thermal behavior of polyethylene (PE) studied by differential scanning calorimetry(DSC) show that crystallinity of the polymer prepared with Et3Al is higher than that with Me3Al or i-Bu3Al. It is also found that the number-average molecular weight ((M) over bar) of the polymers prepared with Me3Al or i-Bu3Al is much higher than that with Et3Al. H-1-NMR studies substantiate that i-Bu3Al is a more efficient alkylation agent of Cp2ZrCl2 in comparison with Me3Al. (C) 1997 John Wiley & Sons, Inc.

COMPATIBILIZING EFFECT OF POLY(ETHYLENE OXIDE)-B-POLYSTYRENE-B-POLY(ETHYLENE OXIDE) IN PHENOLPHTHALEIN POLY(ETHER ETHER KETONE) POLY(2,6-DIMETHYL-1,4-PHENYLENE OXIDE) BLENDS

The morphology and mechanical behaviour of phenolphthalein poly(ether ether ketone) (PEK-C)/poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) blends has been investigated. A poly(ethylene oxide)-b-polystyrene-b-poly(ethylene oxide) (PEO-PS-PEO) triblock copolymer was used as compatibilizer. It was found that PEO-PS-PEO has a compatibilizing effect on the PEK-C/PPO blends. The addition of PEO-PS-PEO to the blends greatly improves phase dispersion and interfacial interfacial adhesion and also enhances the ultimate tensile strength and Young's modulus at compositions ranging from 30 to 70% PEK-C. However, all the values of the ultimate tensile strength within the whole composition range are lower than those expected by simple additivity, probably owing to the poor mechanical properties of PEO-PS-PEO copolymer.

Characterization of the artificially covalent conjugate of B-phycoerythrin and R-phycocyanin and the phycobilisome from Porphyridium cruentum

B-phycoerythrin (BPE) and R-phycocyanin (RPC) were purified from Porphyridium cruentum by Sephadex G-200 chromatography, then the BPE was attached covalently to the RPC by reacting their amino groups to form the artificially covalent BPE-RPC conjugate in which the excitation energy can transfer from the BPE to the RPC with low efficiency. Meanwhile, the intact phycobilisome (PBS) consisting of BPE, RPC, APC and L-CM was isolated and purified from Porphyridium cruentum, and the purified PBS was found to keep intact if the solution contains sucrose. Comparison of spectroscopic properties between the purified PBS and the BPE-RPC conjugate suggests that the BPE-RPC conjugate is much more stable than the purified PBS. The construction of BPE-RPC conjugate with low efficiency of the excitation energy transfer may be useful for preparing phycobiliprotein probes. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

Isolation, properties and spatial site analysis of gamma subunits of B-phycoerythrin and R-phycoerythrin

Polysiphonia urceolata R-phycoerythrin and Porphyridium cruentum B-phycoerythrin were degraded with proteinaseK, and then the nearly native gamma subunits were isolated from the reaction mixture. The process of degradation of phycoerythrin with proteinaseK showed that the gamma subunit is located in the central cavity of (alpha beta)(6) hexamer of phycoerythrin. Comparative analysis of the spectra of the native phycoerythrin, the phycoerythrin at pH 12 and the isolated gamma subunit showed that the absorption peaks of phycoerythrobilins on alpha or beta subunit are at 535 nm (or 545 nm) and 565 nm, the fluorescence emission maximum at 580 nm; the absorption peak of phycoerythrobilins on the isolated gamma subunit is at 589 nm, the fluorescence emission peak at 620 nm which overlaps the absorption maximum of C-phycocyanin and perhaps contributes to the energy transfer with high efficiency between phycoerythrin and phycocyanin in phycobilisome; the absorption maximum of phycourobilin on the isolated gamma subunit is at 498 nm, which is the same as that in native phycoerythrin, and the fluorescence emission maximum at 575 nm.

Molecular cloning and functional analysis of cathepsin B in nutrient metabolism during larval development in Meretrix meretrix

Seed rearing is an important part in large scale clam culture industry. Since the nutritional history affects early development in bivalve, the condition of larval nutrition plays a key role in successful seed rearing. So far, the molecular mechanism of nutrient uptake in bivalve larvae is unclear. As one of the important proteolytic enzymes, cathepsin B of several organisms has been reported to be involved in digestion. We intended to analyze whether cathepsin B is involved in larval nutrient metabolism in the economic bivalve, clam Meretrix meretrix. The full length of M. meretrix cathepsin B (MmeCB) cDNA was cloned, which is 1647 bp with an open reading frame of 1014 bp. The deduced amino acid sequence encoded a preproenzyme of 337 residues with Cys-114, His-282 and Asn-302 composing cathepsin B activity center. The temporal and spatial expressions of MmeCB mRNA were examined from trochophore to post larva stages by whole mount in situ hybridization. In trochophore stage, no detectable signal was found. In the later three stages, MmeCB mRNA was detected in the digestive gland, suggesting a possible role of MmeCB in digestion. Moreover, MmeCB mRNA was also observed in the epidermal cells in D-veligers. Cathepsin B specific inhibitor (CA074 methyl ester) was applied to block the activity of cathepsin B in unfed larvae. The average shell lengths of treated larvae were smaller than that in control groups. The results of mRNA epidermal distribution and inhibitor treatment in D-veligers indicated that MmeCB may be also associated with other pathway of nutrient metabolism in larval epidermis. The overall results in this paper revealed that MmeCB might play a role in larval nutrient metabolism. (C) 2008 Elsevier B.V. All rights reserved.

Scophthalmus maximus cystatin B enhances head kidney macrophage-mediated bacterial killing

Cystatins form a large family of cysteine protease inhibitors found in a wide arrange of organisms. Studies have indicated that mammalian cystatins play important roles under both physiological and pathological conditions. However, much less is known about fish cystatins. In this report, we described the identification and analysis of a cystatin B homologue, SmCytB, from turbot Scophthalmus maximus. The open reading frame of SmCytB is 300 bp, which encodes a 99-residue protein that shares high levels of sequence identities with the cystatin B of a number of fish species and contains the conserved cysteine protease inhibitor motif of cystatin B. Constitutive expression of SmCytB is high in muscle, brain, heart and liver, and low in spleen. blood, gill and kidney. Bacterial infection upregulates SmCytB expression in kidney, spleen, liver and brain but not in muscle or heart. Functional analysis showed that recombinant SmCytB purified from Escherichia colt exhibits apparent cysteine protease inhibitor activity. Transient overexpression of SmCytB in head kidney macrophages enhances macrophage bactericidal activity probably through a nitric oxide-independent mechanism. These results indicate that SmCytB is involved in the immune defense of turbot against bacterial infection. (C) 2010 Elsevier Ltd. All rights reserved.

Expression of beta-carotene hydroxylase gene (crtR-B) from the green alga Haematococcus pluvialis in chloroplasts of Chlamydomonas reinhardtii

A carotenoid gene (crtR-B) from the green alga Haematococcus pluvialis, encoding beta-carotene hydroxylase that was able to catalyze the conversion of beta-carotene to zeaxanthin and canthaxanthin to astaxanthin, was cloned into Chlamydomonas reinhardtii chloroplast expression vector p64D to yield plasmid p64DcrtR-B. The vector p64DcrtR-B was transferred to the chloroplast genome of C. reinhardtii using micro-particle bombardment. PCR and Southern blot analyses indicated that crtR-B was integrated into the chloroplast genome of the transformants. RTPCR assays showed that the H. pluvialis crt R-B gene was expressed in C. reinhardtii transformants. The transformants rapidly synthesized carotenoids in larger quantities than the wild-type upon being transferred from moderate to high-intensity white light. This research provides a foundation for further study to elucidate the possible mechanism of photo-protection by xanthophylls and other carotenoids in high light conditions or through exposure to UV radiation.

Photosynthesis of Saussurea superba and Gentiana straminea is not reduced after long-term enhancement of UV-B radiation

Experiments were conducted in an alpine Kobresia humilis meadow near Haibei Alpine Meadow Ecosystem Research Station (37degrees29'-37degrees45'N, 101degrees12'-101degrees33'E; altitude 3200 m). Effects of enhanced ultraviolet-B (UV-B) radiation on photosynthesis of the alpine plants of Saussurea superba and Gentiana straminea were investigated. Both species were exposed to a UV-B-BE density at 15.80 kJ m(-2) per day, simulating nearly 14% ozone (O-3) reduction during the plant growing season. Neither photosynthetic CO2 uptake rate nor photosynthetic O-2 evolution rate were decreased after a long period of enhanced UV-B radiation treatment. On the contrary, there was a tendency to increase of both parameters in both species. The photosynthetic pigments were also increased, when expressed on a leaf area basis. UV-B absorbing compounds, detected by the absorbance values at 300 mm, had a tendency to increase in both species after enhanced UV-B radiation. After long-term exposure of plants to enhanced UV-B radiation, leaf morphology was also affected. Leaf thickness in both S. superba and G. straminea were increased significantly (P < 0.001). This supports our hypothesis that the increase of leaf thickness in both species after long-term exposure of enhanced UV-B radiation could compensate for the photodestruction of photosynthetic pigments when light passes through the leaf. Therefore, photosynthesis is not reduced in either species when expressed on leaf area basis. (C) 2003 Elsevier B.V. All rights reserved.

塔A和塔B地区古地温与热演化史研究

1）依据镜质组反射率（或由沥青、无定形干酪根换算成的镜质组反射率）拟合计算沉积盆地及生油层古地温是一种比较实用而又简便可行的方法。2）从十二口井井温数据分析，除X6井(2.0℃/100M)和X1井(2.05℃/100M)外，其它十口井的现地温梯度均小于2℃/100M。塔里木盆地的现地温梯度是较低的。3）拟合计算古地温的结果表明，塔B和塔A地区古地温梯度偏低半呈下降的趋势：塔B地区古生代隆起区古地温梯度为3.5℃/100M，凹陷区为3.0℃/100M，中生代古地温梯度为2.5-2.7℃/100M，新生代古地温梯度为2.0-2.2℃/100M。塔A及塔C地区：古生代隆起区的古地温梯度为3.5℃/100M，凹陷区为3.0℃/100M；中生代古地温梯度为2.5℃/100M，新生代为2.0-2.2℃/100M，今地温梯度为2.0℃/100M。4）古地温拟合计算结果表明：塔B地区志留系至二叠系地层基本被剥蚀，有的部位下古地层也遭到部分剥蚀。寒武-奥陶系总厚度在3000-4000米以上，生油层的生油期持续时间很长。寒武系底的生油期从寒武纪末到石炭纪（522-342Ma），目前普遍处在干气阶段。奥陶系底的生油期从奥陶纪末期一直持续到第三纪，90%的地区生油高峰期在泥盆纪末（早海西运动以后）之后（见图3-12），目前普遍处于凝析油-湿气阶段。塔A地区志留、泥盆系基本被剥蚀殆尽，而寒武-奥陶系基本未被剥蚀，总厚度在2000-4000米之间。寒武系底的生油期从寒武纪末期到泥盆纪（511-362Ma），至今大部分处于生气阶段。奥陶系底的生油期从泥盆纪一直到第三纪（404-40Ma），约30%的地区生油高峰期在泥盆纪末（早海西运动）之后（见图3-？），至今部分生油岩处于生气阶段。由于受加里东和海西运动的影响，塔A和塔B地区古生界地层普遍存在“二次生油”的现象。两地区石炭-二叠系一般在第三纪开始生油，生油期普遍较短。相对塔B和塔A地工而言，塔C地区受构造运动而遭剥蚀的程度要小得多。寒武-奥陶系总厚度范围为2100-8200米，因此生油层的生油期持续时间很长。寒武系底的生油期从中寒武世到石炭纪（536.5-305Ma）。奥陶系底的生油期从晚奥陶世一直到第三纪晚期（439.5-16.5Ma），仅少数地区生油高峰期在泥盆纪末（早海西运动）之后，目前大部分处于凝析油-湿气到干气阶段。石炭、二叠、三叠及侏罗系生油层目前大都处于“生油窗”内。总之，本区是塔A和塔B地区的主要油源区。5）通过对有机包裹体类型和荧光性质的鉴定、数量的统计、以及盐水溶液包裹体均一温度的测定，可以初步了解有机质热演化程度及含油气情况。6）对中生代样品，Tmax反映的成熟度与其它参数基本一致，而对于古生代样品，由于样品成熟度增大，Tmax失去指示成熟度的作用。原油和生油岩生物标志化合物反映的成熟度基本上与其它指标一致，因此在缺乏反射率资料的地区，可用生物标志化合物近似反映成熟度的变化。

Perovskite-type B-site Bi-doped ceramic membranes for oxygen separation

Novel mixed conducting oxides, B-site Bi-doped perovskites were exploited and synthesized. Cubic perovskite structures were formed for BaBi0.2COyFe0.8-yO3-delta (y less than or equal to 0.4) and BaBixCo0.2Fe0.8-xP3-delta (x=0.1-0.5) The materials exhibited considerable high oxygen permeability at high temperature. The oxygen permeation flux of BaBi0.2Co0.35Fe0.45O3-delta membrane reached about 0.77 x 10(-6) mol/cm(2) s under an air/helium oxygen partial pressure gradient at 900 degrees C, which was much higher than that of other bismuth-contained mixed conducting membranes. The permeation fluxes of the materials increased with the increase of cobalt content, but no apparent simple relationship was found with the bismuth content. The materials also demonstrated excellent reversibility of oxygen adsorption and desorption. Stable time-related oxygen permeation fluxes were found for BaBi0.2CO0.35Fe0.45O3-delta and BaBi0.3Co0.2Fe0.5O3-delta a membranes at 875 degrees C.

Characterization and thermodynamic study of ultra-fine particle of Ni-B amorphous alloy

Ultra-fine particle of Ni-B amorphous alloy was prepared by chemical reduction of Ni2+ with NaBH4 and characterized with TEM and XRD. The heat capacity and thermal stability were measured with a high-precision automatic adiabatic calorimeter and DTA. The upper limit of applied temperature of the substance was found to be 684 K for use as catalyst. (C) 1999 Elsevier Science B.V. All rights reserved.