多种高分子材料制备氟苯尼考固体分散体及其对比分析

利用高分子材料制备固体分散体是当前最有效最便捷的改变非水溶性药物的水溶解度和生物利用度的方法之一。为探究临床常见药用高分子材料载体的优越性和差异性,利用聚乙二醇(PEG)6000、PEG4000、聚维酮(PVP)k30、PVPk15、泊洛沙姆188等高分子材料为载体,采用熔融法、溶剂法和溶剂熔融法制备氟苯尼考固体分散体,溶出速率法验证固体分散体,比较氟为尼考原料、物理混合物及固体分散体的溶解度和累积溶出率。结果表明：几种固体分散体均可提高氟苯尼考药物的溶解度和体外溶出速率,其增溶效果为PEG6000>PEG4000>PVPk30>PVPk15>188,氟苯尼考与PEG6000配比在1∶4时溶解度和体外溶出速率均最优,是最佳配比。5种不同高分子材料制备氟苯尼考固体分散体,制备方法简便易操作、质量可控,能提高药物的溶解度,其中PEG6000增溶效果最优,可广泛应用。     

Crystallization of single and binary iron‐ and aluminum hydroxides affect phosphorus desorption

In acidic soils, phosphorus availability is affected by its strong affinity for mineral surfaces, especially Fe‐ and Al‐hydroxides. Plant roots have developed adaptive strategies to enhance the availability of phosphorus, including producing and exuding low molecular weight organic acids with a high affinity for phosphorus that competes with high molecular weight organic ligands formed during humification and mineralization. The aim of this study was to characterize the kinetics and mechanism of phosphorus desorption from Fe‐ and Al‐hydroxides of variable crystallinity, as well as binary Fe:Al‐hydroxide mixtures. Long‐term desorption experiments (56 days) were conducted with CaCl₂, CaSO₄, citric acid, and humic acid as competitive sorptives. CaCl₂ and CaSO₄ were selected as general inorganic sorptives and citric and humic acids were selected as organic ligands produced by organisms in the rhizosphere or following humification. The cumulative phosphorus desorption increased following the order CaCl₂ < CaSO₄ < humic acid < citric acid. Amorphous ferrihydrite and Fe‐rich Fe:Al‐hydroxides exhibited much less desorption when exposed to inorganic solutions than the crystalline and Al‐rich Fe:Al‐hydroxide mixtures. Models of the desorption data suggest phosphorus desorption with citric acid is diffusion‐controlled for ferrihydrite and Fe‐rich amorphous Fe:Al‐hydroxides. When humic acid was the sorptive, metal‐organic complexes accumulated in the solution. The results suggest organic compounds, especially citric acid, are more important for liberating phosphorus from Fe‐ and Al‐minerals than inorganic ions present in the soil solution.     

纤维素溶解机理研究述评

纤维素是植物细胞壁的主要组分之一,是由葡萄糖通过1,4-β糖苷键连接而成的均一聚糖,广泛应用于生产酯类、醚类等纤维素基化工产品。纤维素基产品的制备及应用与其溶解程度密切相关,探究纤维素溶解机理,寻找一种绿色高效的纤维素溶剂至关重要。综述了当前国内外学者们对纤维素溶解机理的解释(氢键破坏理论)以及可能影响溶解的因素(化学热力学、化学动力学、结晶度、纤维素两亲性、电荷数和温度),在此基础上探讨了导致纤维素水溶性差的原因,提出了在复杂体系中除了氢键作用以外,还需要综合考虑范德华力、疏水性相互作用的影响。同时,总结了纤维素在离子液体中溶解机理方面存在的争议,其中关于氢键理论还存在一定问题,动力学控制理论尚不明确,阳离子在溶解过程所起的作用被忽视,指出离子液体阳离子的两亲性是纤维素溶解的关键因素。基于纤维素的两亲性及两亲性溶剂促进纤维素溶解的重要理论,提出了应重点寻找新型两亲性溶剂的观点,为未来寻求高效、环境友好、成本低廉的纤维素溶剂指明了方向。     

Contamination of Radio active Substances in Grapes

We have studied the quantitative analysis of potassium in agricultural materials by measuring the radioactivity of K4o by means of Radiation Counter since 1951. When the fundamental experiment was almost over and we were to begin the applications in fertilizers and crops, we found unexpectedly in May 1954, rain containing fission products presumably carried from H-bomb explosion test at Bikini. Temporarily abstaining from the experiment, we surveyed the degree of contamination of radioactive substances in crops, especially grapes, which are the main horticultural crop in this prefecture. Here, we explain the experimental data of the radioactivity in the grapes and the relations between the contamination of the artificial radioactivity and the potassium content in them.     

造纸法再造烟叶提取过程中关键化学成分的溶出规律

为研究造纸法再造烟叶提取过程中关键化学成分(水溶性总糖、钾离子、还原糖、烟碱、氯离子和总氮)的溶出规律,采用连续流动分析法对烟梗和烟片原料以及提取过程中固形物中各关键化学成分进行了分析。结果表明,在提取过程中,除总氮外,水溶性总糖、钾离子、还原糖、烟碱和氯离子的溶出速率均呈现三个阶段:0~15 min,急速下降区;15~25 min,下降区;25~40 min,平缓区。烟片中水溶性总糖、还原糖和烟碱的溶出速率大于其在烟梗中的溶出速率;烟片中钾离子和氯离子的溶出速率小于其在烟梗的溶出速率。烟梗和烟片在提取过程中,总氮基本不溶出;提取进行至40 min时,烟梗和烟片固形物中仍有部分水溶性总糖、还原糖、钾离子和氯离子等没有溶出。仅采用水提法无法将原料中各关键化学成分有效地提取出来。     

Alkaline weight reduction monitoring of sea-island type polyamide microfiber fabrics

The alkaline dissolution behavior of sea-island type polyamide microfibers were successfully monitored using a cationic dye staining method. Weight reduction behavior of the alkali-treated microfiber fabrics and the treated fabrics stained with cationic dye were investigated in a comparative manner. The termination of dissolution monitored by both methods was also confirmed by scanning electron microscopy.     

Influence of a Sargassum forest on the spatial distribution of water flow

The influence of a Sargassum forest on the spatial distribution of water flow generated by waves and tidal currents was investigated. Water flow was measured horizontally and vertically by using plaster balls at a Sargassum forest in Saiki Bay facing the Bungo Channel, on the Pacific Coast of Kyushu Island, Japan, from 7 to 9 March 1989 during the luxuriant growth season of Sargassum species. Plaster balls were deployed at several depths at stations placed with horizontal scales of 10–100 m. Wet weight loss of plaster balls immersed in the field for 50 h was converted to the speed of steady flow (named intensity of water motion) that brought the equivalent loss in a tank experiment. The results clarified that the spatial distribution of water flow showed good correlation with that of the standing crop of Sargassum forest, and that the intensity of water motion was appreciably diminished in the Sargassum forest. We also discuss ecological implications of the reduction in water flow within the Sargassum forest for the growth and settlement of Sargassum species.     

地美硝唑盐片剂的制备及体外溶出度

采用紫外分光光度法，对用淀粉、糊精和微晶纤维素等辅料制备的地美硝唑盐片剂和未成盐地美硝唑片剂进行了体外溶出度和释药动力学的比较研究。结果表明，在人工肠液中，两者累积释药50％的时间分别为7.59min和18.26min，前者的溶出速率明显快于后者。本品在45min内可溶解80％以上，释药规律符合Weibull方程。