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991.
Shuqin Han Yuji Kanematsu Kazuyuki Hattori Hideki Nakashima Takashi Yoshida 《Journal of polymer science. Part A, Polymer chemistry》2009,47(3):913-924
A new anhydro disaccharide monomer, 1,6‐anhydro‐2,3‐di‐o‐benzyl‐4‐o‐(2′,3′,4′,6′‐tetra‐o‐benzyl‐β‐D ‐galactopyranosyl)‐β‐D ‐glucopyranose (benzylated 1,6‐anhydro lactose (LSHBE)), was synthesized from D ‐lactose to investigate the polymerizability and biological activities of the resulting branched polysaccharides. The ring‐opening polymerization of LSHBE was carried out with phosphorus pentafluoride as a catalyst under high vacuum to give a stereoregular benzylated (1 → 6)‐α‐D ‐lactopyranan. The molecular weights of poly(LSHBE)s increased with an increase in the amount of CH2Cl2 solvent, and polymerization temperatures were affected in both molecular weights and yields of the polymers. The copolymerization of LSHBE with benzylated 1,6‐anhydro‐β‐D ‐glucopyranose (LGTBE) gave the corresponding copolysacchrides having different proportions of lactose and glucose units in good yields. After debenzylation to recover hydroxyl groups and then sulfation, sulfated homopoly(lactose)s and copoly(lactose and glucose)s were obtained. Sulfated homopoly(lactose)s had moderate anti‐HIV (EC50 = 5.9 and 1.3 μg/mL) and blood anticoagulant activities (AA = 18 and 13 unit/mg), respectively. Sulfated copoly(lactose and glucose) having 15 mol % lactose units gave high anti‐HIV and blood anticoagulant activities of 0.3 μg/mL and 54 unit/mg, respectively. These biological results suggest that the distance between branched units on the main chain plays an important role in the anti‐HIV and blood anticoagulant activities. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 913–924, 2009 相似文献
992.
Stefan Baudis Christian Heller Robert Liska Juergen Stampfl Helga Bergmeister Guenter Weigel 《Journal of polymer science. Part A, Polymer chemistry》2009,47(10):2664-2676
Cardiovascular disease is one of the leading causes of morbidity and mortality in the western hemisphere. Currently available synthetic vascular conduits, like Dacron or ePTFE show excellent long‐term results for large‐caliber arterial reconstruction (aorta, iliac vessels) but when used for small diameter (<4 mm) vessel reconstruction, patency rates are extremely poor. We therefore aim at developing suitable blood vessel substitutes out of biocompatible photopolymer formulations, which can be printed by rapid prototyping. Rapid prototyping offers the possibility to create cellular structures within the grafts that favor the ingrowth of tissue. To meet the high requirements for artificial biomaterials, it is necessary to develop new resin formulations. Beside the biocompatibility, the mechanical properties—a low elastic modulus (500 kPa) at a relatively high tensile strength (1.0 MPa) and a high strain at break (130%)—play a central role. Resin systems containing cyanoethyl acrylate have shown to be highly reactive, have good mechanical properties and sufficient in vitro biocompatibility. Elastic modulus and tensile strength which should be similar to natural blood vessels were adjusted by the ratio of acrylate‐based crosslinkers and—in case of hydrogels —the percentage of water. Finally, we were able to print small diameter conduits by microstereolithography. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2664–2676, 2009 相似文献
993.
KIO4-鲁米诺化学发光体系测定青霉素钠 总被引:1,自引:0,他引:1
在碱性介质中,KIO4氧化鲁米诺产生化学发光,青霉素钠对该体系有增强作用.在最佳的实验条件下,青霉素钠浓度与增强的发光强度成正比,线性范围为0.01~20μg/mL,检出限(3σ)为3.0 ng/mL,对1.0μg/nL青霉素钠进行11次平行测定,其相对标准偏差为1.2%.方法已用于粉针剂、合成样品及尿样中青霉素钠的测定. 相似文献
994.
Small ball estimates are obtained for Brownian motion and the Brownian sheet when balls are given by certain Hölder norms. As an application of these results we include a functional form of Chung's LIL in this setting.Both authors were supported in part by NSF Grant Number DMS-9024961. 相似文献
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997.
以实验室养殖的幼小大菱鲆和养殖场养殖大菱鲆幼鱼为研究对象,研究了转牙鲆生长因子基因集胞藻作为饲料添加剂对鱼类血液生理生化指标和红细胞微核率及核异常率的影响。研究结果显示,转基因集胞藻对大菱鲆血液红细胞和白细胞数量、血红蛋白含量及红细胞体积没有影响(p〉0.05);1.0%添加剂量没有引起血清转氨酶活性及碱性磷酸酶和乳酸脱氢酶活性增加(p〉0.05),实验组血清蛋白质、葡萄糖、甘油三脂、胆固醇、尿素氮和肌酐含量以及钾、钠、氯、磷浓度与对照组之间也不存在显著性差异(p〉0.05);转基因集胞藻对红细胞微核及核异常没有诱导作用。结果表明转基因集胞藻不会引起大菱鲆组织器官损伤,也没有遗传毒性,是一种安全的转基因饲料添加剂,可以用作大菱鲆促生长剂使用。 相似文献
998.
在强平稳m相依样本下讨论了均值的经验似然置信区间估计,推广了Owen[1—2]在独立同分布情况下的结果.指出其不足并进行了合理的改进,并提出了分组经验似然的概念. 相似文献
999.
血型分布规律初探 总被引:2,自引:0,他引:2
曾庆黎 《数学的实践与认识》2004,34(2):70-75
以马氏链为工具对人类 ABO血型的分布规律做了初步探讨 .用群体遗传学的理论对所建数学模型进行了解释和论证 .提出了一个新的检验稳定 (即平衡 )的方法 . 相似文献
1000.
A mathematical model for the thermoregulation in the dermal layers of the human body is proposed. The skin is composed mainly
of three layers — epidermis, dermis and subcutaneous tissues. The relative constancy of the body temperature is remarkable
because there is a continuous exchange of heat with the external environment as well as within the different compartments
of the body. A model describes the distribution of dermal temperature as a function of internal and external parameters, such
as temperature of the incoming arterial blood, blood flow, ambient temperature, and heat exchange with the environment. It
is shown that substantial changes in human dermal temperature can be accomplished only through changes in the temperature
of the incoming arterial blood or substantial suppression of blood flow. Other parameters can lead only to temperature changes
near the skin surface. 相似文献