New analytical method for the study of the metabolism of gentiopicroside in rats after oral administration by LC–TOF‐MS following picolinoyl derivatization

The metabolism of gentiopicroside (GPS) in vivo was studied for the first time by LC–MS following picolinoyl derivatization. Incubation of erythrocentaurin, one of the main in vitro metabolites of GPS by intestinal bacteria, with liver microsome indicated that GPS might be metabolized to a final metabolite 3,4‐dihydro‐5‐(hydroxymethyl)isochroman‐1‐one (HMIO) in vivo. After hydrolysis with sulfatase, HMIO was successfully detected in rat plasma after oral administration of GPS by LC–MS following picolinoyl derivatization. 4‐Methoxyphenyl methanol was used as an internal standard to quantify HMIO in rat plasma. A metabolic pathway of GPS in rats is proposed. The monoterpene compound GPS was found to be metabolized to dihydroisocoumarin, which may be responsible for the pharmacological effect of GPS.     

LaPO4∶Eu3+—Fe3O4光-磁复合材料的合成与性能研究

采用2步水热法合成了LaPO4∶Eu3+-Fe3O4复合材料.在LaPO4∶Eu3+-Fe3O4复合材料中,LaPO4∶Eu3+为单斜晶相,呈纳米棒状,纳米棒的直径和长度分别为20~100nm和0.2~1μm;Fe3O4为正交晶相、呈20~30nm的颗粒状,Fe3O4粒子紧紧附着在LaPO4∶Eu3+纳米棒的表面;样品的磁性和发光性质研究表明所合成的LaPO4∶Eu3+—Fe3O4复合材料既具有发光性质又具有磁性.     

Improved Polysaccharide Production in Submerged Culture of Ganoderma lucidum by the Addition of Coixenolide

Polysaccharides from Ganoderma lucidum have various bioactivities and have been widely used as nutraceuticals and functional foods. Coixenolide was added into the media to enhance the production of mycelia biomass and polysaccharides in the submerged culture of G. lucidum in this work. The results showed that when a level of 0.2 % coixenolide was added at day 1, the biomass, exopolysaccharide, and intracellular polysaccharide reached 5.224, 0.222, and 0.399 g l^?1, respectively, which were 1.39-fold, 2.58-fold, and 2.24-fold compared to that of control. Analysis of the fermentation kinetics of G. lucidum suggested that glucose concentration in the coixenolide-added group decreased more quickly as compared to the control group from days 3 to 9 of the fermentation process, and the polysaccharides biosynthesis were promoted at the same culture period. However, the culture pH profile was not affected by the addition of coixenolide. Enzyme activities analysis indicated that coixenolide affected the synthesis level of phosphoglucose isomerase and α-phosphoglucomutase.     

多壁碳纳米管QuEChERS/气相色谱-质谱联用法快速检测黄芪中16种农药

建立了QuEChERS/气相色谱-质谱联用法(GC-MS)同时测定黄芪中α-六六六、β+γ-六六六、δ-六六六、五氯硝基苯、p,p′-滴滴伊、o,p′-滴滴涕、p,p′-滴滴滴、p,p′-滴滴涕、甲霜灵、二嗪磷、七氯、嘧菌环胺、腐霉利、顺式氯丹、反式氯丹、咯菌腈16种农药残留的分析方法。样品前处理采用改进的QuEChERS方法,黄芪粉加水浸润后,乙腈涡旋振荡提取,多壁碳纳米管(MWCNTs)、正丙基乙二胺(PSA)、MgSO_4净化,结合GC-MS检测系统,电子轰击源(EI),HP-5ms毛细管柱分离,程序升温,离子扫描模式(SIM)检测。在优化条件下,16种农药在0.01～5.0 mg/L质量浓度范围内线性关系良好,相关系数不低于0.974,方法的定量下限(S/N=10)为0.002～0.035 mg/kg,平均回收率为71.9%～115%,相对标准偏差(RSD)为1.2%～14%。该方法具有操作简单快捷、灵敏度高等优点。     

Solvent‐Free Self‐Assembly for Scalable Preparation of Highly Crystalline Mesoporous Metal Oxides

Mesoporous metal oxides (MMOs) have been demonstrated great potential in various applications. Up to now, the direct synthesis of MMOs is still limited to the solvent induced inorganic‐organic self‐assembly process. Here, we develop a facile, general, and high throughput solvent‐free self‐assembly strategy to synthesize a series of MMOs including single‐component MMOs and multi‐component MMOs (e.g., doped MMOs, composite MMOs, and polymetallic oxide) with high crystallinity and remarkable porous properties by grinding and heating raw materials. Compared with the traditional solution self‐assembly process, the avoidance of solvents in this method not only greatly increases the yield of target products and synthesis efficiency, but also reduces the environmental pollution and the consumption of cost and energy. We believe the presented approach will pave a new avenue for scalable production of advanced mesoporous materials for various applications.     

On Domination Number of 4-Regular Graphs

Let G be a simple graph. A subset S V is a dominating set of G, if for any vertex v V – S there exists a vertex u S such that uv E(G). The domination number, denoted by (G), is the minimum cardinality of a dominating set. In this paper we prove that if G is a 4-regular graph with order n, then (G) ⁴/₁₁ n     

微弱信号源的和波束定向方法与分裂波束定向方法的性能比较

本文讨论水下辐射噪声源的精确定向问题，给出被动声纳和波束定向与分裂波束定向方法的性能比较。指出在一定信噪比下，分裂波束精确测向技术比和波束定向技术具有较高的定向精度。但是，随着信噪比的下降，两者趋于一致。推导了估计定向精度的分析表达式，给出在直线阵和圆弧阵情况下，延时估计和声源入射角偏差之间的换算公式和数值模拟结果。同时给出数字式声纳用以计算入射信号左波束和右波束数据的互谱来实现分裂波束定向的方法。     

隔热材料的纳米成型与性能分析

经不同工艺和过程制备二氧化硅气凝胶,初步摸索出制备温度、溶剂、催化剂、反应时间最佳参数.在分析气凝胶干燥开裂的原因后,以三甲基氯硅烷(TMCS)为表面修饰剂,正己烷为干燥介质的表面改性工艺,一定程度控制了气凝胶的干燥收缩和开裂.在室温、常压下的通过不同的改性方案制备出四种不同气凝胶样品,揭示了改性条件、干燥温度对于气凝胶孔隙分布、微观结构的影响.     

Graphs whose endomorphism monoids are regular

In this paper, we give several approaches to construct new End-regular (-orthodox) graphs by means of the join and the lexicographic product of two graphs with certain conditions. In particular, the join of two connected bipartite graphs with a regular (orthodox) endomorphism monoid is explicitly described.