川黄柏中盐酸小檗碱HPLC测定优化及其抑菌活性评价

为建立高效液相色谱（HPLC）测定川黄柏结晶物中盐酸小檗碱含量的优化方法，并评价川黄柏对耐药性细菌的抑制活性，对川黄柏提取物进行结晶处理后，通过对流动相及检测条件的优化确定最优检测方法；用结晶物对耐药性菌株进行体外抑菌试验评价抑制活性。结果表明，检测最佳条件：流动相为乙腈-0.1%磷酸溶液（50∶50）（0.1 g十二烷基硫酸钠每100 mL磷酸溶液），检测波长为265 nm，流速1 mL·min-1，柱温30 ℃；当盐酸小檗碱浓度在103~515 mg·L-1之间时，与各自对应峰面积积分值呈较好的线性关系（R2=0.999 7）；对该条件下测定过程进行精密度、稳定性、重复性试验检测，RSD分别为0.49%、1.23%、0.29%，表明试验方法准确；平均加样回收率为97.84%~98.06%，RSD为0.44%~1.00%，说明检测方法准确有效。抑菌活性试验发现川黄柏结晶物对耐药性金黄色葡萄球菌(Staphylococcus aureus)和铜绿假单胞菌(Pseudomonas aeruginosa)均有很好的抑制效果。优化方法安全、快速、精确、有效，可用于黄柏药材中盐酸小檗碱的分析测定；川黄柏中盐酸小檗碱具有很好地抑菌作用。研究拓宽了对抗耐药性细菌的天然产物种类，为其临床应用和科学研究奠定基础。     

低聚木糖溶液冷冻浓缩时冰晶生长动力学研究

研究了低聚木糖溶液冷冻浓缩时搅拌速度、冰晶种量和冷媒温度对冰晶生长动力学的影响。结果表明,随着晶核成熟时间的增加,冰晶生长速度下降,而且,生长时间1 ~3 h,生长速度下降最快。搅拌速度越高、冷媒温度越低,冰晶生长速度越快,而且冰晶生长速度下降得越慢。冰晶种量越大,冰晶生长的初始速度越快;但冰晶种量过高,反而使冰晶生长的速度的降低加快。在低聚木糖初始质量浓度10.3 g/L、初始溶液体积400 mL、搅拌速度500 r/min、冷媒温度为-1.5℃条件下,适宜的冰晶种量为10 g。     

用X射线衍射法测定木材纤维次生壁的平均微纤丝角

测定木材次生壁上的平均微纤丝角是研究木材细胞壁构造的关键环节,本文介绍了一种先进的X射线衍射测定法。     

建筑风场任意六面体同位网格系统的数值模拟

开发了建筑风场数值模拟程序W SB,自动生成任意六面体同位网格系统,建立控制方程的离散方式,实现与网格系统相适应的通用S IM PLE算法.对于网格非正交性和两相邻单元的中心连线与其公共面中心点的错位等两方面进行的修正,以显式的处理归入源项中,以保证控制方程离散的统一性和程序的通用性.通过对双坡屋面建筑模型的风场数值模拟和正方体网格系统的建筑风场数值模拟结果进行比较,以及与风洞试验结果相比较,都有相一致的结果.     

Elastic Band Gaps in Two-dimensional Phononic Crystals Based on Multiple-scattering Theory

Two dimensional solid phononic crystals such as plates, shells can be widely applied to the control of vibration and noise as a kind of structural materials. It is very significant to study the band gaps in two dimensional phononic crystals to apply them in the vibration and noise control for structures and as a filter for acoustical signal. The multiple-scattering theory is integrated with wave equations to study the elastic wave band gaps in two-dimensional phononic crystals. The carbon/proxy system is used as numerical example. The results show that a full band gap is presented when carbon cylinder with high propagation velocity is arranged periodically in proxy with low propagation velocity.     

Discussion of the Negative Thermal Expansion Coefficient of the Laminar Crystal

The variation of the thermal expansion coefficient of the graphite crystal is derived. According to the theory of temperature with the thermodynamic and statistical physical, the free energy of the graphite crystals is given with the De-Bye Model, and relationship between the thermal expansion coefficient of the graphite crystal and the temperature range is probed. The results are showed: the thermal expansion coefficient is equal to zero if T =0 K or T is on the verge of the 15 K or 42 K; negative if the temperature is in the range of 15 to 42 K; constant if the temperature is higher. The theoretical calculations accord with the experimental results. From this, In the layered crystals the reason that there is the negative expansion is that the statistical weight of the transverse acoustic vibration for the atoms in the plane layer is very large. In some temperature ranges, the variation of distance between atoms in the direction perpendicular to the plane layer with the temperature resulted in by the transverse acoustic vibration reverses with that in the plane layer. Then the film effect is resulted in.     

影响生产小檗胺结晶因素的研究

通过研究影响小檗胺结晶与提取溶剂的关系、与萃取剂加入量的关系、与盐析的关系，阐明了提高小檗胺结晶的得率的方法。     

What is your diagnosis? Intracranial mass in a cat

Abstract: A 14‐year‐old female spayed cat was presented with a 3–4‐month history of circling to the left and intermittent head pressing. Neurologic examination findings localized the lesion to the left supratentorial region. Using magnetic resonance imaging, an extra‐axial mass was found on the dorsal aspect of the brain at the level of the frontal and parietal lobes, compressing and displacing the brain ventrally and caudally. Craniectomy was performed and the mass was submitted for cytologic and histopathologic evaluation. Impression smears revealed abundant cholesterol crystals and loose clusters of mildly pleomorphic spindle cells, compatible with a meningioma. The histopathologic diagnosis was meningioma with psammoma bodies and numerous cholesterol clefts. Abundant cholesterol crystals within meningiomas in cats may present a diagnostic challenge when nucleated cells are scant. Other differential diagnoses for abundant cholesterol crystals in an intracranial mass include cholesterol granulomas and keratinizing cysts.     

苏云金芽孢杆菌的概况及其研究进展

苏云金芽孢杆菌(Bacillus thuringiensis,Bt)杀虫剂是对人和环境友好的安全型细菌杀虫剂。目前Bt杀虫剂已被广泛应用,但因使用剂量较大,导致防治害虫时费用过高。若在生物防治中使用超高效的细菌杀虫剂,就可降低其使用剂量。Bt 00-50-5菌株是从美国引进的高效杀虫菌株,其晶体蛋白的特征分析尚未完成,其毒素的作用机理研究也未进行。本项目即将开展如下研究:(1)先用具有特异性杀虫功能的Bt 00-50-5菌株进行发酵,继续完成对防治中国害虫防治效果的评价;再分析细菌的编码杀虫毒素基因和毒素的生化特征;然后混合荧光标记毒素和中肠细胞,加入昆虫中肠蛋白酶(或单独加入氨肽酶、碱性磷酸酶、ATP酶、枯草杆菌蛋白酶、钠或钾离子代之)反应,用荧光显微镜观察细胞变化;最后阐明杀虫毒素对靶标细胞作用机制。(2)通过研究毒素分子与受体分子的作用关系,拟在分子水平上阐明毒素的作用机制。     

竹杆锈病防治试验研究

竹杆锈病发生较广泛,危害淡竹、刚竹、桂竹等。经农药防治试验表明,用晶体石硫合剂防治效果最好,连防3年,防治效果达88.1%～98.6%,感病指数为0.54～4.8。70%的代森锰锌和20%粉锈宁次之,效果分别为83.9%～87.6%和84%～87.4%。