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1.
制备了以葡聚糖作为交联剂的氨基苯硼酸类糖敏感微凝胶,用1H-NMR和FT-IR表征了其结构。利用微凝胶的不同条件下的粒径变化,深入研究了该类凝胶对糖浓度的刺激响应行为。结果表明,葡聚糖的引入使微凝胶在生理条件下具有更加优秀的依糖刺激响应行为。  相似文献   

2.
通过点击化学在聚乙二醇单甲醚(MPEG)端基分别修饰了葡萄糖(Glc)、甘露糖(Man)和半乳糖(Gal),制备了一系列端基为糖的聚乙二醇单甲醚(MPEG-Glc、MPEG-Man和MPEG-Gal),此类端基为糖的MPEG和α-环糊精(α-CD)混合后能够形成稳定的准聚轮烷(PPR)水凝胶,而端基没有修饰糖的MPEG和α-CD只能形成黏度较大的溶液而无法形成稳定存在的凝胶.通过流变仪测试可知水凝胶的弹性模量高达1.0×105 Pa,远大于文献中通过黏土等增强的PPR水凝胶的强度,我们认为该MPEG端基的糖之间能够形成新的"糖交联"点从而有效提高了凝胶的强度.通过向水凝胶中加入和MPEG端基的糖具有相互作用的苯硼酸半酯聚合物(PNIPAM-co-PBOB)或刀豆蛋白(Con A),发现在凝胶中加入PNIPAM-co-PBOB或Con A后可明显降低PPR水凝胶的强度.通过扫描电镜(SEM)和X射线衍射(XRD)对水凝胶的形貌以及微观结构进行表征分析,发现此凝胶的微观结构和文献中报道的PPR水凝胶基本一致,进一步证明了上述结论.  相似文献   

3.
分别采用果冻和琼脂作为凝胶载体设计成微型电解实验,探究电解过程中两极发生现象的原理。  相似文献   

4.
用自由基引发3-丙烯酰胺基苯硼酸(AAPBA)、N,N-二甲基丙烯酰胺(DMAA)和丙烯酰胺(AAm)共聚交联制得新型三嵌段水凝胶P(AAPBA-co-DMAA-co-AAm), 与传统的两嵌段聚合物相比, 该凝胶具有良好的糖敏感特性, 在质量浓度200 mg/dL以上有较高的糖响应特性, 这一数值接近糖尿病病人的血糖阈值, 其溶胀度达10倍以上, 同时糖响应时间缩短到2~3 h. 振荡实验结果表明, 所得凝胶对糖呈现出良好的刺激-响应特性.  相似文献   

5.
无外相的葡聚糖凝胶的合成   总被引:2,自引:0,他引:2  
本文研究了无外相的葡聚糖凝胶的合成方法以及有关的催化剂用量,糖液浓度,反应时间,反应温度,交联剂用量和不同分子量的葡聚糖与合成凝胶的性能关系,并确定了最佳反应条件,从而制得了性能类似国外同类产品Sephadex的凝胶。  相似文献   

6.
为拓宽多重响应性凝胶在生物医学领域中的应用,本文基于生物大分子构筑具有pH响应、糖响应性的可自修复性水凝胶。 本文选用3-氨基苯硼酸(APBA)和2,3-环氧丙基三甲基氯化铵(CHGTA)分别对聚谷氨酸(γ-PGA)和瓜尔胶(GG)进行改性制备了聚谷氨酸-g-氨基苯硼酸(γ-PGA-g-APBA)和阳离子瓜尔胶,在此基础上,对γ-PGA-g-APBA和阳离子瓜尔胶进行物理共混制备生物基凝胶。 通过傅里叶变换红外光谱仪(FTIR)、核磁共振波谱仪(1H NMR)和流变仪对聚合物化学结构、接枝率、流变性能和力学性能进行表征,并考察了凝胶在不同pH值及糖浓度下刺激响应性。 结果表明,凝胶具有自修复性,修复效率可达100%;具有pH响应性,在环境pH值较高时更易形成凝胶,且凝胶强度随pH值升高而增大;同时所制凝胶具有糖响应性,在4 g/L的葡萄糖溶液中浸泡后即可导致凝胶解体。 这些结果说明功能基团APBA的引入可赋予凝胶多重响应性。 所制的双重响应性生物基凝胶具有良好的生物相容性,有望应用于生物医学、功能器件、传感等领域。  相似文献   

7.
通过水热合成和高温煅烧的方法制备了多孔氮掺杂碳基复合气凝胶,其可作为一种高效的催化剂.该方法是以蒲绒和石墨烯气凝胶作为碳源和模板,尿素作为氮源.分别采用XRD,FT-IR,Raman和TEM对这些催化剂进行表征分析.以叔丁基过氧化氢为氧化剂,探究该复合气凝胶在乙苯选择性氧化生成苯乙酮的反应体系中的催化性能,实验结果表明,该复合气凝胶在该体系中具有优异的催化活性,苯乙酮的选择性可达92%以上.这是由于复合气凝胶中的多孔结构,氮元素的掺杂以及蒲绒和石墨烯气凝胶之间的相互作用.将生物质蒲绒转化为高催化活性碳材料,这种新颖的方法为寻找高性能催化氧化乙苯的催化剂提供了新的设计前景.  相似文献   

8.
为解决毛细管凝胶电泳中胶管制备困难和检测背景高等关键问题,设计了一种以梯度结构为基础的低背景聚丙烯酰胺凝胶毛细管及其快速灌制方法。新式胶管在分离未经衍生的多聚核苷酸、人工蛋白和生物糖等重要的生物大分子时表现出了稳定、高效、灵敏和快速的特点。  相似文献   

9.
为获得系列α-1,2-葡聚寡糖,首先以蓝藻寡糖六糖、八糖、九糖和十糖为原料,在0.5 mol/L的三氟乙酸(TFA)中于95℃酸解9 min以脱去还原端果糖,经低压凝胶色谱分离纯化,用电喷雾离子化-碰撞诱导解离-串联质谱(ESI-CID-MS/MS)和基质辅助激光解吸电离质谱(MALDI-MS)鉴定和序列表征,获得了除去末端果糖的α-1,2-五、七、八和九糖;然后在0.5 mol/L的TFA中于95℃对混合蓝藻寡糖六糖和八糖酸水解45 min,用Bio-Gel P2凝胶柱对混合物进行分离和纯化,并通过ESI-MS和MALDI-MS对获得的每个寡糖组份进行表征,获得了聚合度为2,3,4和6的α-1,2-葡聚寡糖.本研究为利用糖生物芯片技术进行α-1,2-葡聚寡糖的功能筛选及分析其与靶标蛋白之间相互作用的特异性提供了葡聚寡糖物质基础.  相似文献   

10.
糖芯片研究     
糖芯片是继基因芯片、蛋白质芯片、组织芯片等之后发展起来的一种很有前景的生物检测技术,具有检测样品用量少、特异性高、高通量等优点,可以大大提高糖化学研究的效率。本文介绍利用共价结合法和非共价吸附法制备二维糖芯片,利用聚合反应制备三维凝胶芯片以及糖芯片在凝集素功能研究、病毒转染机制研究、细菌检测和免疫学研究等方面的应用,最后对糖芯片今后的发展进行了展望。  相似文献   

11.
利用手持技术改进测定乙醇分子结构实验   总被引:1,自引:0,他引:1  
利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。  相似文献   

12.
13.
由于石化行业的生产需要,其材质的使用具有多样性和广泛性,经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识,根据光谱仪的测试能力及标样的采集,实现了一个或几个元素测量范围的扩展,并对其测量的影响因素进行了研究。  相似文献   

14.
The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.  相似文献   

15.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

16.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

17.
实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。  相似文献   

18.
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.  相似文献   

19.
Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.  相似文献   

20.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

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