富含氨基的聚酰胺-胺树枝状大分子的合成与表征

以乙二胺(EDA)和丙烯酸甲酯(MA)为原料,采用发散法合成了0.5代到3.0代聚酰胺-胺(PAMAM)树枝状大分子。分别考察了反应温度、反应时间对半代及整代PAMAM树枝状大分子合成工艺的影响,并对合成的PAMAM产物进行了傅里叶变换红外光谱(FTIR)、高效液相色谱(HPLC)表征及端基滴定分析。实验结果表明,生成PAMAM半代及整代产物的最适反应温度均为25℃,反应时间为24 h;采用该方法合成的3.0G PAMAM树枝状大分子的纯度为88.22%,表面伯胺数约为16个,与理论值一致。合成的PAMAM树状分子表层富含大量的氨基基团,可以与抗体、核酸适体等功能分子结合而应用于食品安全检测和医药领域。     

肝靶向药物载体半乳糖基蛋白的合成及其特性研究

目的：合成肝靶向药物载体半乳糖基人血清白蛋白．并探讨其生物学特性。方法：以半乳糖和人血清白蛋白为原料．合成半乳糖基人血清白蛋白．利用现代生物质谱技术,分析该药物载体的纯度和糖密度;并用^131I标记与模型药物5一氟脲啶偶联后的肝靶向药物载体．进行动物体内靶向性作用的研究。结果：合成的肝靶向药物载体具有较高的纯度,糖密度(即每分子人血清蛋白偶联半乳糖的分子数)达到了51：1．具有显著的趋肝性,肝脏摄取率达到75．0％。结论：合成的肝靶向药物载体半乳糖基人血清白蛋白是优良的受体介导的肝靶向药物载体。     

Synthesis and characterization of anisometric cobalt nanoclusters

Sonication of aqueous Co(2+) and hydrazine resulted in the formation of anisometric (disk-shaped) cobalt nanoclusters that averaged about 100 nanometers in width and 15 nanometers in thickness. Electron diffraction from single particles revealed that they were oriented (001) crystals that conformed to a trigonal or hexagonal unit cell four times the size of the cell adopted by bulk alpha-cobalt. Lorentz microscopy indicated that these were single-magnetic domain particles, with the axis of magnetization located in the (101) plane, offset at some appreciable angle from the (001) axis.     

环丙氨嗪人工抗原的合成与鉴定

本研究拟通过抗原合成、多克隆抗体制备等途径建立快速的环丙氨嗪酶联免疫检测方法.主要采用戊二醛桥连法,偶联半抗原环丙氨嗪和载体牛血清白蛋白(BSA)或卵清白蛋白(OVA),制备酶联检测的免疫抗原和包被抗原.经紫外光谱和气相-傅里叶-红外光谱鉴定,在紫外265 nm波长处得到环丙氨嗪-BSA吸收峰;在红外3 350～3 300 cm-1、1 660～1 500 cm-1和1 695～1 665 cm-1波长处分别得到环丙氨嗪-BSA和环丙氨嗪-OVA特征性偶联吸收峰,证实本试验人工合成的2对抗原均偶联成功.免疫抗原和包被抗原的偶联比分别达到25.9 ∶ 1、23.1 ∶ 1,为进一步制备抗血清和酶联检测方法的建立奠定了工作基础.     

棉属AD远缘杂种的合成及性状鉴定

[目的]棉属A、D组棉种是研究物种形成过程中生殖隔离机制和基因组互作的良好材料,本研究旨在获得AD远缘杂种并从形态学初步鉴定杂种的真实性,探讨A、D组棉种间生殖隔离的先后顺序,并进一步探究亲本基因组在杂种中的互作模式。[方法]选用A组亚洲棉、草棉为母本,D组雷蒙德氏和瑟伯氏棉为父本进行远缘杂交,获得杂种并进行统计分析和形态性状鉴定。[结果]结果表明四个组合中只有亚雷、草雷和亚瑟获得杂种并长成植株,亚雷和草雷组合的杂种植株长势旺盛并能开花,且杂种大部分性状间于双亲之间;亚瑟组合收到种子并能成苗,但植株生长受阻不现蕾;草瑟组合没有收到饱满种子。[结论]草瑟组合属于合子前生殖隔离;草雷、亚雷、亚瑟生殖隔离是由合子前和合子后生殖隔离共同起作用。且草雷、亚雷杂种基因组互作亲和,而亚瑟杂种基因组互作不亲和。D组雷蒙德氏棉能同时和A1、A2组杂交成功并获得杂种后代,进一步验证了雷蒙德氏棉被视为四倍体棉种祖先的直接证据。     

Synthesis and characterization of helical multi-shell gold nanowires

Suspended gold nanowires were made in an ultra-high vacuum. The finest of them was 0.6 nanometer in diameter and 6 nanometers in length. By high-resolution electron microscopy, they were shown to have a multi-shell structure composed of coaxial tubes. Each tube consists of helical atom rows coiled round the wire axis. The difference between the numbers of atom rows in outer and inner shells is seven, resulting in magic shell-closing numbers.     

Synthesis and characterization of castor oil-based polymeric surfactants

Dehydrated castor oil was epoxidized using phosphoric acid as a catalyst and acetic acid peroxide as an oxidant to produce epoxidized castor oil (ECO). Ring-opening polymerization with stannic chloride was used to produce polymerized ECO (PECO), and sodium hydroxide used to give hydrolyzed PECO (HPECO). The HPECO was characterized by Fourier transform infrared, ¹H and ¹³C nuclear magnetic resonance spectroscopies, gel permeation chromatography, and differential scanning calorimetry. The weight-average molecular weight of soluble PECO and HPECO were 5026 and 2274 g·mol^-1, respectively. PECO and HPECO exhibited glass transition. Through neutralizing the carboxylic acid of HPECO with different counterions, castor oil-based polymeric surfactants (HPECO-M, where M= Na⁺, K⁺ or triethanolamine ion) exhibited high efficiency to reduce the surface tension of water. The critical micelle concentration (CMC) values of HPECO-M ranged from 0.042 to 0.098 g·L^-1 and the minimum equilibrium surface tensions at CMC (g_cmc) of HPECO-M ranged from 25.6 to 30.0 mN·m^-1. The water-hexadecane interfacial energy was calculated from measured surface tension using harmonic and geometric mean methods. Measured values of water-hexadecane interfacial tension agreed well with those calculated using the harmonic and geometric mean methods.     

苦皮藤素Ⅴ人工抗原的合成与鉴定

采用琥珀酸酐法合成了苦皮藤素 的衍生物苦皮藤素 -半琥珀酸酯(CA-SG),在此基础上,分别采用混合酸酐法和碳化二亚胺法合成了苦皮藤素 的人工抗原(CA-BSA,CA-BSA2),采用紫外分光光度计法、SDS-PAGE及PAGE电泳法对合成的人工抗原进行了定性鉴定,结果均表明人工抗原合成成功。根据半抗原、人工抗原及其载体在240nm处的紫外吸光值,计算出2种人工抗原中半抗原与载体的分子结合比率分别为11.6和10.7。     

Synthesis and characterization of the nitrides of platinum and iridium

Transition metal nitrides are of great technological and fundamental importance because of their strength and durability and because of their useful optical, electronic, and magnetic properties. We have evaluated a recently synthesized platinum nitride (PtN) that was shown to have a large bulk modulus, and we propose a structure that is isostructural with pyrite and has the stoichiometry PtN2. We have also synthesized a recoverable nitride of iridium under nearly the same conditions of pressure and temperature as PtN2. Although it has the same stoichiometry, it exhibits much lower structural symmetry. Preliminary results suggest that the bulk modulus of this material is also very large.     

若干单核锰配合物的合成与表征

首次合成了三种单核锰配合物ＭｎＬ２１ＰｈＣＯＯ－，ＭｎＬ２２ＰｈＣＯＯＨ，ＭｎＬ２２ＨＡｃ．其中配体ＨＬ１，Ｈ２Ｌ２分别为三齿配体水杨醛缩邻苯二胺和水杨叉邻氨基酚；Ｐｈ为苯基．运用元素分析、化合价测定、电导率和磁化率测定、热重分析、ＩＲ、Ｕｖ－Ｖｉｓ、ＥＳＲ等方法对其性质进行了研究，提出了配合物可能的结构．     

一类具有可变时滞的非线性中立型差分方程的振动性

考虑一类具有可变时滞的非线性非自治中立型差分方程，得到了这类方程的振动准则及这类方程存在最终正解的充分条件。     

三甲基硅羟乙基纤维素醚的合成、表征及性能

通过羟乙基纤维素（HEC）与六甲基二硅胺烷的反应,对水溶性物质HEC三甲基硅化改性,以改善其脂溶性。用红外光谱和扫描电镜（SEM）分析了产物的结构和表面形貌,并用热质量分析（TGA）、示差扫描量热（DSC）对改性产物的热性能进行了表征,应用霉菌法进行了生物降解性能实验。结果表明,HEC经硅化改性后,脂溶性得到改善;热分解温度显著提高,热稳定性得到增强;通过观测产物经过霉菌不同时间降解后的表面形貌,证明羟乙基纤维素三甲基硅醚具有生物降解性。图8表4参11     

含偶氮类光学活性侧基淀粉的合成及表征

以硫酸铈铵盐和过硫酸钾-亚硫酸氢钠为引发剂,十二烷基苯磺酸钠为乳化剂,引发可溶性淀粉与3种偶氮苯衍生物的乙烯基单体接枝共聚.通过TGA、DSC、SEM等手段对接枝共聚物结构的表征,证明发生了接枝共聚反应.     

以4,4'-联吡啶为配体的木犀草素药物共晶的合成及表征

利用溶液挥发法首次合成1个全新的木犀草素-4,4'-联吡啶药物共晶,并通过红外光谱、核磁共振、X射线粉末衍射及差示扫描热量分析等对其表征。选择不同物质量比的木犀草素与4,4'-联吡啶及不同反应溶剂为主要影响因素,探索并确定相应合成条件:木犀草素和4,4'-联吡啶以13的物质量比混合后溶于7.0 m L丙酮溶剂,25℃下搅拌3 h后,于室温下挥发,5 d后得到黄褐色粉末状晶体。结果表明,在极性相对较小的溶剂体系中,反应物分子间形成数目合适且方向饱和的氢键连接,可有效促进药物共晶生成。     

羟丙基淀粉/DMAEMA接枝共聚物的合成与表征

为研究接枝反应条件对羟丙基淀粉接枝共聚物的影响,选用甲基丙烯酸二甲氨基乙酯(Dimethylaminoethyl methacrylate,DMAEMA)为接枝单体,过硫酸钾为引发剂,通过溶液合成法制备了羟丙基淀粉接枝共聚物.研究了反应温度、聚合时间、引发剂用量对接枝共聚反应的影响,并利用傅立叶变换红外光谱、热重分析、...     

Single-bond formation and characterization with a scanning tunneling microscope

A scanning tunneling microscope (STM) was used to manipulate the bonding of a carbon monoxide (CO) molecule and to analyze the structure and vibrational properties of individual products. Individual iron (Fe) atoms were evaporated and coadsorbed with CO molecules on a silver (110) surface at 13 kelvin. A CO molecule was transferred from the surface to the STM tip and bonded with an Fe atom to form Fe(CO). A second CO molecule was similarly transferred and bonded with Fe(CO) to form Fe(CO)(2). Controlled bond formation and characterization at the single-bond level probe chemistry at the spatial limit.     

非线性中立型时滞差分方程的振动性

考虑具有可变时滞的非线性非自治中立型差分方程, △(xn-Pnxn-l) qnf(xn-kn)=0,n=0,1,2…,得到了这类方程振动的几个充分条件.     

Synthesis and solid-state NMR structural characterization of 13C-labeled graphite oxide

The detailed chemical structure of graphite oxide (GO), a layered material prepared from graphite almost 150 years ago and a precursor to chemically modified graphenes, has not been previously resolved because of the pseudo-random chemical functionalization of each layer, as well as variations in exact composition. Carbon-13 (13C) solid-state nuclear magnetic resonance (SSNMR) spectra of GO for natural abundance 13C have poor signal-to-noise ratios. Approximately 100% 13C-labeled graphite was made and converted to 13C-labeled GO, and 13C SSNMR was used to reveal details of the chemical bonding network, including the chemical groups and their connections. Carbon-13-labeled graphite can be used to prepare chemically modified graphenes for 13C SSNMR analysis with enhanced sensitivity and for fundamental studies of 13C-labeled graphite and graphene.     

A single adenosine with a neutral pKa in the ribosomal peptidyl transferase center

Biochemical and crystallographic evidence suggests that 23S ribosomal RNA (rRNA) is the catalyst of peptide bond formation. To explore the mechanism of this reaction, we screened for nucleotides in Escherichia coli 23S rRNA that may have a perturbed pKa (where Ka is the acid constant) based on the pH dependence of dimethylsulfate modification. A single universally conserved A (number 2451) within the central loop of domain V has a near neutral pKa of 7.6 +/- 0.2, which is about the same as that reported for the peptidyl transferase reaction. In vivo mutational analysis of this nucleotide indicates that it has an essential role in ribosomal function. These results are consistent with a mechanism wherein the nucleotide base of A2451 serves as a general acid base during peptide bond formation.     

腐乳中产生物胺菌株的筛选鉴定及产生物胺能力评价

为筛选腐乳样品中产生物胺的菌株,以24种市售腐乳样品为研究对象,通过生物胺初筛培养基显色反应进行初筛,再采用高效液相色谱(HPLC)定量分析其产胺能力,获得61株具有氨基酸脱羧酶活性的菌株。选取产生物胺总量较高的20株菌,经16S rDNA分析,这20株菌均为芽孢杆菌属,其中包括6株枯草芽孢杆菌(Bacillus subtilis)、5株巨大芽孢杆菌(Bacillus megaterium)、3株长形赖氨酸芽胞杆菌(Lysinibacillus macrolides)、2株蜡样芽孢杆菌(Bacillus cereus)和4株热带芽孢杆菌(Bacillus tropicus)。还分析了温度、氨基酸浓度、NaCl浓度、乙醇浓度、pH值对产胺量较高的枯草芽孢杆菌和热带芽孢杆菌产胺能力的影响。结果表明:NaCl浓度8%和乙醇浓度10%对生物胺的合成有显著的抑制作用,可应用于腐乳生产中,能有效控制腐乳中生物胺的含量。