维生素C二步发酵中巨大芽孢杆菌对氧化葡萄糖酸杆菌生长和产酸的影响

通过测定氧化葡萄糖酸杆菌转化L－山梨糖中成ZKGA的细胞酶活性、摇瓶发酵及中长变化，研究了Vc:步发酵中巨大茅孢杆菌对氧化葡萄糖酸杆菌生长和产酸作用的影响。结果显示：巨大芽孢杆菌胞外液和胞内液均可促进氧化葡萄糖酸杆菌的增殖，主要表现为缩短其中长周期中的延迟期；巨大芽孢杆菌通过所产生的部分生物活性物质增强氧化葡萄糖酸杆菌产酸的细胞酶活性，促进氧化葡萄糖酸杆菌转化L一山梨糖生成2KGA.

卫星表面光学反射特性建模与仿真研究

在研究空间相机成像效果探测问题时,针对提高探测相机成像真实效果的需要,研究了卫星表面光学反射特性的建模与仿真方法。利用双向反射分布函数(BRDF)仿真卫星表面的光学反射特性,将卫星表面物理特性与其光学反射特性有机地结合起来。在VC.Net环境下开发卫星表面光学反射特性仿真软件,并将软件集成到空间探测相机成像效果仿真平台上。利用平台进行成像仿真实验,生成真实感仿真图片。仿真结果表明,BRDF能够精确仿真卫星表面的光学反射特性,使成像效果仿真更加准确和逼真。

基于HLA的仿真模型管理方法研究

“仿真是一种基于模型的活动”，任何仿真系统都不能离开模型的支持，如果每次开发新的系统都要重新建立模型，费时费力。随着仿真系统的日益复杂，导致仿真模型的结构也日趋复杂，模型管理亦日趋繁琐。因此，研究一种有效的模型管理方法，对于方便模型重用，提高开发效率有着重要的意义。实现对模型的有效管理，首先需要明确管理对象，然后把模型有条理的分类并且规范的描述出来，最后把模型存储在数据库中，供用户重用。论文首先在HLA联邦开发执行过程的基础上，分析和完善了HLA仿真建模体系，明确了HLA仿真中模型的层次；然后总结了现有的模型分类方法，从方便模型统一管理的角度，提出了一种可扩展的模型分类方法；引入了元数据和XML技术，实现了对模型的规范化描述；根据课题研究目的，提出了仿真模型管理系统的设计目标，并设计了系统的体系结构、功能模块和数据结构；最后，综合应用数据库、VC++等技术，实现了模型存储、模型的增、删、改、查以及用户管理等功能，实现了对于模型的统一管理。

Preparation of TiO2 nanocrystallites by hydrolyzing with gaseous water and their photocatalytic activity

TiO2 nanocrystallites were prepared front precursors tetra-n-butyl titanate (Ti(OC4H9)(4)) and titanium tetrachloride (TiCl4). The precursors were hydrolyzed by gaseous water in autoclave, and then calcined at predetermined testing temperatures. The samples were characterized by X-ray diffraction (XRD), thermogravimetry-differential thermal analysis (TG-DTA), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectra (FT-IR), and UV-vis diffuse reflectance spectra (DRS). The photocatalytic activities of the samples were evaluated by the photobleaching of methylene blue (MB) in aqueous solution and the photocatalytic oxidation of propylene in gas phase at ambient temperature. The results showed that the anatase phase nanocrystalline TiO2 could be obtained at relatively low temperatures (for precursor Ti(OC4H9)4 at I I VC and for TiCl4 at 140 degrees C, respectively), and that the as prepared samples exhibited high photocatalytic activities to photobleach MB in aqueous solution. As the calcination temperatures increasing. the decolor ratio of MB increased and reached the maximum value of nearly 100% at 600 degrees C, and then decreased. The photobleaching of MB by all samples followed the pseudo-first-order kinetics with respect to MB concentration.

Investigation of the self-accelerating process of ascorbic acid by in-situ circular dichroism spectroelectrochemistry

The electrode reaction process of ascorbic (Vc) was studied by in-situ circular dichroic(CD) spectroelectrochemistry with a long optical path thin layer cell on glassy carbon(GC) electrode. The spectroelectrochemical data were analyzed by the double logarithmic method together with nonlinear regression. The results suggested that the mechanism of Ve in pH 7.0 phosphate buffer solution at GC electrode was a two-electron irreversible electrooxidation followed by adsorption of the oxidation product. That is a self-accelerated process. Some kinetic parameters at free and at adsorbed electrode surface, i.e, the formal potentials, E-0' = 0.09 V, E-a(0') = 0.26 +/- 0.02 V; the electron transfer coefficient and number of transfered electron, alpha n = 0.41, alpha(a)n = 0.07;the standard heterogeneous electron transfer rate constant, k(0) = 8.0 x 10(-5) cm.s(-1), k(a)(0) = 1.9 x 10(-4) cm.s(-1) and adsorption constant, beta = 102.6 were also estimated.

Barrier properties of vinylidene chloride copolymers

The permeability coefficients of a series of copolymers of vinylidene chloride (VDC) with methyl acrylate (MA), butyl acrylate (BA) or vinyl chloride (VC) (as comonomer) to oxygen and carbon dioxide have been measured at 1.0 MPa and 30 degrees C, while those to water vapor have been measured at 30 degrees C and 100% relative humidity. All the copolymers are semicrystalline. VDC/MA copolymers have lower melting temperature compared with VDC/BA copolymers, while that melting temperature of VDC/VC copolymer is higher than that of VDC/acrylate copolymers with the same VDC content. The barrier property of the copolymers is predominantly controlled by crystallite, free volume fraction, and cohesive energy. The permeability coefficients of VDC/MA copolymers to oxygen, carbon dioxide, and water vapor were successfully correlated with the ratio of free volume to cohesive energy.

越冬针叶叶绿体超氧阴离子自由基波谱

以Tiron为自旋探针,从越冬针叶叶绿体检出了代表超氧阴离子自由基的TH·ESR信号。此信号可由紫外辐射或光合活性光诱导产生。以单位叶绿素量计算的信号强度比现有文献报导大2—3个数量级。红松信号大于其它针叶树。信号可被外源SOD、VC、乙醇和脱氧所抑制。在一定条件下,随光照增强而增强,12月至5月也表现出逐渐增强的趋势,给自由基诱导红松越冬光氧化伤害理论提供了直接证据。

BIOMIMITICS OF OXIDASE AND OXYGENASE THE ELECTRONIC SPECTRA AND THE OXYGEN UPTAKE KINTICS FOR MPc AND MTPP (M = Fe, Co, Cu, Pc AND TFP - ARE DIANIONS OF PHTHALOCYANIN AND TETRAPHENYLPORPHYRINE, RESPECTIVELY)

The reaction rates of MTPP with oxygen in air are Inas than that with pure oxygen, the ratio is roughly the same as to the partial presence of imygen in air, The influences of S-ligand etbanethiol and O- litand Vc on the above Systems have also been investigated, the former makes the MP hands having more changes and the reaction rate constants becoming greater, the latter has less influence.

L-抗坏血酸与稀土离子作用的NMR研究

利用稀土诱导位移方法研究了水溶液中L-抗坏血酸(Vc)与三价稀土离子的配位作用。在弱酸性条件下二者形成1:1的配合物,稳定常数为8.0M~(-1)。抗坏血酸通过内脂环3位碳上的羟基氧与稀土离子配位,RE~(3+)-O键长为2.0,内脂基和其他碳上的羟基不与稀土离子配位。在配合物中C(3)-C(4)-C(5)-C(6)成反式构象。C(5)-C(6)键与配合物的零偶极位移锥面交叉。

Inhibition of mouse liver lipid peroxidation by high molecular weight phlorotannins from Sargassum kjellmanianum

The inhibitory effects of high molecular weight phlorotannins (HMP) from Sargassum kjellmanianum on mouse liver lipid peroxidation were investigated by spectrophotometric methods. The content of malondialdehyde (MDA) in liver samples was measured by TBA (thiobarbituric acid) assay. It showed that HMP significantly inhibited the generation of MDA in vivo and in situations induced by CCl4 and Fe2+-Vc ( ascorbic acid), and significantly decreased membrane swelling of mouse liver mitochondria, compared with controls ( p < 0.01). HMP were found to have strong anti-oxidative activity in inhibiting mouse liver lipid peroxidation.

三类新型壳聚糖衍生物的制备及其抑菌、抗氧化活性研究

本论文制备了三类新型壳聚糖衍生物，并对其抑菌及抗氧化活性进行了筛选与研究，具体结果如下。 通过在不同分子量的壳聚糖上引入1，3，5-噻二嗪硫酮首次合成壳聚糖噻二嗪硫酮衍生物（N-2-对氨基苯磺酰噻二嗪硫酮-壳聚糖（SATTCS）， N-2-邻甲基苯噻二嗪硫酮-壳聚糖（TITTCS）, N-2-邻氯苯噻二嗪硫酮-壳聚糖（CITTCS））；通过将羟丙基壳聚糖与不同的醛反应首次合成了羟丙基壳聚糖希夫碱（羟丙基壳聚糖水杨醛希夫碱（HHPCS）, 羟丙基壳聚糖5-氯水杨醛希夫碱（HCHPCS）, 羟丙基壳聚糖5-硝基水杨醛希夫碱（HNHPCS）, 羟丙基壳聚糖5-溴水杨醛希夫碱（HBHPCS）, 羟丙基壳聚糖糠醛希夫碱（FHPCS））；通过将不同分子量的壳聚糖与乙酰芳香胺反应首次合成了壳聚糖乙酰芳香胺衍生物（壳聚糖乙酰苯胺（ABCS）, 壳聚糖乙酰芳邻氯苯胺（ACCS），壳聚糖乙酰芳对甲苯胺（TDCS）, 壳聚糖乙酰甲萘胺（MDACS））。采用红外、元素分析等方法进行了结构鉴定。 通过对金黄色葡萄球菌、八叠菌、大肠杆菌、绿脓杆菌，芦笋茎枯病菌等一些真菌的抑菌活性研究表明：壳聚糖噻二嗪硫酮衍生物、壳聚糖乙酰芳香胺衍生物具有较好的抑制细菌的活性，且衍生物对金黄色葡萄球菌的抑制效果最好。分子量不同，抑菌活性也不同。其中，SATTCS和 LMANCS对细菌的抑制效果最好， SATTCS和TDCS的对真菌的抑菌活性最为显著。 抗氧化活性筛选结果表明：壳聚糖噻二嗪硫酮衍生物和羟丙基壳聚糖希夫碱具有很强的清除羟自由基的能力，清除能力全部优于Vc: 壳聚糖噻二嗪硫酮衍生物还具有较强的还原能力,其中TITTCS的还原能力比Vc强；并且，低分子量的壳聚糖噻二嗪硫酮衍生物的清除羟自由基的能力以及还原能力略强于高分子量的壳聚糖噻二嗪硫酮衍生物。 通过本研究工作制备了三类新型壳聚糖衍生物；生物活性研究表明：壳聚糖噻二嗪硫酮衍生物和壳聚糖乙酰芳香胺衍生物在抑菌方面具有应用潜力。研究成果对深入开发利用甲壳质资源，促进我国海洋药物的发展具有重要的意义。

羟基自由基降解琼胶及其产物的活性研究

琼胶是一种从石花菜等红藻中提取的，目前生产工艺和结构等方面研究比较成熟的海藻多糖，广泛应用于医药、仪器等行业。但是，海藻多糖因为具有分子量大，粘度大，溶解度较小的等特点，而使其应用范围受到限制。利用降解的手段对其进行修饰，降低分子量和粘度，改善溶解性，可以拓展其应用范围。并且根据文献报道，琼 胶寡糖具有一些特殊的生物活性，如抗氧化性，抗炎症等。因此，对琼胶降解的研究具有生要意义。本研究中，为了选择一种合适的降解方法，进行了几种水解方法的尝试，其中包括在不同湿度和酸度下盐酸水解，过氧化氢和醋酸催化水解，Fenton体系羟基自由基降解。对于酸水解和Fenton体系氧化还原降解方法，通过粘度法对反应的速度进行了比较，表明氧化还原降解反应中琼胶的粘度降低比较快，并且具有代表性和新意，确定为本实验的降解琼胶的方法并对氧化还原降解所得的产物进行了活性实验。通过模仿自然界普遍存在的氧化还原降解反应，利用Vc诱导的Fenton体系产生的羟基自由基氧化还原降解琼胶得到低分子量的琼胶。降解产物经过高速离心、60％乙醇沉淀，除去分子量比较大的降解产物和磷酸盐，得到可溶于60％乙醇的分子量估计小于3000的降争产物，其产率为85％。利用经Sephadex-G25凝胶色谱分离所香的不同分子量的级分进行分子量和α－葡萄糖苷酶抑制活性关系的实验。降解产物对α－葡萄糖苷酶的抑制率和各级分的浓度呈线性正相关，并且各级分的IC_(50)则随着分子量的降低而降低。另外，对所得的降解产物混合物进行了红外吸收光谱、质子去偶核磁共震碳谱和负离子基质辅助激光诱导－飞行时间质谱结构分析。结果表明，氧化还原降解反应的专一性差，在得到寡糖的同时，在光谱图中出现一些比较复杂的副产物的结构信息。最后，根据MTT法的原理，以有体皮肤成纤维细胞为材料，通过紫外线辐射产生自由基造成氧化损伤，研究降解产物对成纤维细胞的保护作用。当无紫外线辐射时，降解产物对成纤维细胞具有显著的促进生长增殖作用：当经UVa、UBb辐射时则可以显著地表现出对损伤的保护作用，并且这种促进生长和保护作用呈显著的量效关系，表明降解产物具有清除基自由基的作用。但是，因为氧化还原降解以应的机理尚不十分明的以及琼羟胶的特殊结构，使得反应的副产物很难预测，也就使得分离工作难以进行，所以，根据目前所得的信息，尚不能确定是降解产物的什么级分产生的以上两种生物活性。

壳寡糖及其新型衍生物的制备和抗肿瘤活性初步研究

壳聚糖具有多种生物活性且无毒、无污染，可生物降解，但分子量大，水溶性差，其应用受到很大限制。壳寡糖具有良好的水溶性，其制备方法和应用近年来成为研究的热点。本论文详细研究了酶法和化学法制备壳寡糖的工艺条件，并对酶降解和化学氧化降解的产物进行了比较，结果表明氧化降解的壳寡糖氨基含量有所下降，而酶法降解的产物氨基含量基本没有变化。研究发现在木瓜蛋白酶中加入Vc可以一定程度上降低降解产物的粘度。对几种酶联合降解效果进行了研究，结果表明三种酶的联合降解可得到分子量为1800左右的壳寡糖产物，同时可获得较高产率。 本论文还制备了三种新型壳寡糖衍生物，并研究了壳寡糖和三种衍生物的抗肿瘤活性。通过在壳寡糖上引入胍基乙酸，首次合成了壳寡糖胍基乙酰衍生物(N-2-胍基乙酰-壳寡糖)；引入烟酰氯、烟酰异硫氰酸酯合成了(N-2-烟酰-壳寡糖、N-2-烟酰异硫氰酸酯-壳寡糖)。 通过对BEL•7402肝癌细胞进行了抑制肿瘤活性研究表明：烟酰壳寡糖衍生物的抗肿瘤活性较其他两种衍生物和壳寡糖的活性要好(1mg/ml浓度下抑制率为21.54%)，在较低浓度下有一定的抑制活性（50ug/ml浓度下抑制率为3.57%）。随着浓度的升高，抑制活性也随之提高。烟酰异硫氰酸酯壳寡糖衍生物和胍基乙酰壳寡糖衍生物在低浓度条件下对肿瘤细胞基本没有抑制活性，在高浓度条件下有一定的抑制活性。

Antioxidant activity of differently regioselective chitosan sulfates in vitro

Differently regioselective chitosan sulfates were prepared according to Hanno Baumann's methods. Their antioxidant potencies were investigated employing various established in vitro systems, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH)/superoxide/hydroxyl radicals scavenging, reducing power, iron ion chelating and total antioxidant activity. All kinds of sulfated chitosans (HCTS, TSCTS, SCTS, TCTS) showed strong inhibitory activity toward superoxide radical by the PMS-NADH system compared to Vc. According to the above-mentioned order their IC50 were 0.012, 0.040, 0.015, 0.022mg/mL, respectively, however, scavenging activity of Vc on superoxide radical was 68.19% at 2.0mg/mL. Scavenging activity of superoxide radical was found to be in the order of HCTS > SCTS > TCTS > TSCTS > Vc. Furthermore, all kinds of sulfated chitosans exhibited strong concentration-dependent inhibition of deoxyribose oxidation. Except for HCTS, others had stronger scavenging activity on hydroxyl radical than Vc. Scavenging effect of TSCTS on 1, 1 -diphenyl-2-picrylhydrazy] radical was little lower than that of BHA, but better than that of others. All kinds of sulfated chitosans were efficient in the reducing power, especially TSCTS. TSCTS and TCTS showed considerable ferrous ion chelating potency. The data obtained in vitro models clearly establish the antioxidant potency of all kinds of sulfated chitosans. These in vitro results suggested the possibility that sulfated chitosans could be effectively employed as ingredient in health or functional food, to alleviate oxidative stress. However, comprehensive studies need to be conducted to ascertain the in vivo safety of sulfated chitosans in experimental animal models. (C) 2004 Elsevier Ltd. All rights reserved.

Radical scavenging activity of protein from tentacles of jellyfish Rhopilema esculentum

In this study, radical scavenging activity of protein from tentacles of jellyfish Rhopilema esculentum (R. esculentum) was assayed including superoxide anion radical and hydroxyl radical scavenging. The protein samples showed strong scavenging activity on superoxide anion radical and values EC50 of full protein (FP), first fraction (IFF), second fraction (SF), and 30% (NH4)(2)SO4 precipitate (Fr-1) were 2.65, 7.28, 1.10, and 22.51 mu g/mL, respectively, while values EC50 of BHA, BHT, and alpha-tocopherol were 31, 6 1, and 88 pg/mL, respectively. Also, the protein samples had strong scavenging effect on hydroxyl radical and the values EC50 of FP, FF, SF, Fr-1, and Fr-2 were 48.91, 27.72, 1.82, 16.36, and 160.93 mu g/mL, but values EC50 of Vc and mannitol were 1907 and 4536 mu g/mL, respectively. Of the five protein samples, SF had the strongest radical scavenging activity and may have a use as a possible supplement in the food and pharmaceutical industries. The radical scavenging activity was stable at high temperature so that R. esculentum may be used as a kind of natural functional food. (c) 2005 Elsevier Ltd. All rights reserved.