载异烟肼聚己内酯微球的制备及其性质研究

采用O/O溶剂挥发法制备载异烟肼聚己内酯微球。系统考察了活性剂浓度、内外油相体积、投药量对微球粒径、载药量和包封率的影响。结合内外油相初始粘度分析载药微球成球性,用IR、XRD、SEM对微球化学结构、结晶状态和表面形貌进行表征。通过优化得到平均粒径为28.73μm、载药量为2.36%、包封率为49.58%、外观圆整、表面多孔的载药微球。与O/W溶剂挥发法制备微球对比表明,O/O法有效地提高了载异烟肼聚己内酯微球载药量与包封率,是包覆亲水性小分子药物的可行方法,该载药微球可望用于骨和关节结核病的缓释治疗。     

明胶微球/磷酸镁基骨水泥复合药物缓释体系的构建

采用乳化交联法制备出粒径主要分布在100~300 μm的载药明胶微球, 分析了交联剂含量、药物含量和转速对载药率和包封率的影响及药物含量和转速对微球粒径的影响。对载药明胶微球与磷酸镁基骨水泥进行复合, 探讨微球降解过程中复合体系孔隙率的变化及其在体外药物释放的规律, 以期获得一种具有药物缓释性能的多孔磷酸镁基复合骨水泥。结果表明, 随着葡萄糖浓度增加, 载药率和包封率先上升再下降; 随着药物含量的增加, 载药率保持上升, 包封率先上升后下降; 随着转速增加, 载药率和包封率均下降。综合分析, 在转速为400 r/min、葡萄糖浓度为0.5 g/mL、药物与明胶质量比为1:2的条件下制备的载药明胶微球载药量较高, 且粒径合适。将复合不同比例该载药微球的磷酸镁基骨水泥浸泡在Tris-HCl缓冲溶液中进行体外药物释放研究, 结果表明: 在释放前期(0~10 h)药物释放速率较快, 之后药物释放明显减缓。7 d后, 微球几乎降解完全, 药物释放率达到60%~89%, 达到了一定的药物缓释效果。     

胶原蛋白/壳聚糖/纳米SiO_2复合微球的制备与载药性能研究

采用乳化交联法制备胶原蛋白/壳聚糖/纳米SiO_2复合微球。以司班80和液体石蜡为油相,混合溶液为水相,引入硬脂酸镁(MS)作助乳化剂,以SEM、FT-IR、UV、激光粒度仪为表征手段研究了油水体积比、搅拌速率、交联剂与混合溶液体积比和纳米SiO_2对复合微球的成球性及其载药释药性能的影响。结果表明,MS的助乳化效果较好,在纳米SiO_2和混合溶液质量比为2%(wt,质量分数)时,盐酸小檗碱载药微球的载药率为15.66%,包封率为66.52%,维生素D载药微球的载药率为3.08%,包封率为48.54%。结论:制备了粒度分布集中的药物缓释微球,纳米SiO_2使微球具有更好的缓释性能,且在pH较低时不易分解,减少粘附。     

同轴电喷射法制备核壳结构聚乳酸载药微球

通过同轴静电喷射法制备核-壳结构聚乳酸载药微球。壳层流体为聚乳酸溶液,核层流体为药物水溶液,其中在核层流体中加入壳聚糖以达到在增加溶液电导率的同时改善聚乳酸的亲水性和功能性的目的。实验研究了核、壳层溶液浓度、流量、喷射电压以及接收距离等因素对微球形貌及结构的影响。研究结果表明,当控制实验条件为壳、核层流速比为3∶1,壳层溶液浓度与核层溶液浓度均为1%(质量浓度),喷射电压为20kV,接收距离为15cm,模型药物浓度2mg/mL时,可以得到粒径1μm左右、具有一定缓释效果的核壳结构载药微球,包封率为76.64%,载药量为7.11%。     

内水相结构对微球包封率及控释行为的影响

采用水-油-水双乳化溶剂挥发法制备了聚乳酸-羟基乙酸共聚物(PLGA)/氧氟沙星载药微球,并考察了介孔硅、透明质酸、多聚赖氨酸不同内水相成分对微球粒径及其分布、表面形态、包封率以及释放特性的影响。研究结果表明,采用该方法制备出了内部具有多孔结构的载药微球;透明质酸内水相组微球平均粒度最大,粒径分布最小;介孔硅和透明质酸的加入提高了微球包封率;3种内水相组的初期爆释均高于对照组;多聚赖氨酸内水相组释放速率最快,透明质酸内水相组释放速率最慢。释放拟合曲线表明,4组不同内水相的微球,在释放区间内,释放行为都符合Slogistic方程式。     

可降解聚碳酸亚丙酯马来酸酯载药微球的制备

采用阴离子配位聚合方法,合成了二氧化碳(CO2),环氧丙烷(PO)与马来酸酐(MA)的三元共聚物,聚碳酸亚丙酯马来酸酯 (PPCMA).采用复相乳液(W/O/W)溶剂挥发法制备了包裹水溶性模型药物葡萄糖(glucose)的可降解微球,并研究了壁材与囊心的比例、稳定剂明胶浓度、搅拌速率等因素对微球性能的影响.当v(PPCMA)∶v(glucose)=1∶2,gelatin质量分数为0.2%,第1次乳化搅拌速率为400r/min,第2次乳化搅拌速率为500r/min时,得到粒径较小、载药量和包封率分别为26.1%和76.1%的载药微球.     

聚乳酸-羟基乙酸(PLGA)及其载药微球的制备研究

采用二步法合成了聚乳酸-羟基乙酸(PLGA),研究了聚合工艺对聚合物分子量的影响,进一步以PLGA为原料制备了聚合物微球,筛选并优化了制备微球的聚合物分子量,探索了制备条件对微球粒径、表面形态的影响,确定了较佳工艺条件。PLGA共聚的较优条件为:丙交酯与乙交酯按50∶50摩尔比混合,加入0.06%催化剂Zr(acac)4,常压下150℃共聚6h,PLGA特性黏度[η]为0.1964dL/g。优化后的微球制备工艺条件为:采用浓度为0.3%的吐温20为乳化剂,二氯甲烷为有机相,1000r/min转速乳化30min,500r/min转速挥发6h,水油相体积比(W∶O)为20∶1,聚合物浓度为0.05g/mL,此条件下制得微球表平均粒径为214nm。     

PLGA／TPGS-姜黄素纳米粒的制备及体外评价

以维生素E1000聚乙二醇琥珀酸酯（TPGS）为乳化剂,姜黄素为模型药物,聚乳酸-羟基乙酸为载体材料,采用O／W型乳化-溶剂挥发法制备聚乳酸-羟基乙酸-姜黄素纳米粒,以包封率和载药量为主要指标,单因素实验探索影响两指标的主要因素,正交试验设计优化制备工艺,结果表明,制备聚乳酸-羟基乙酸-姜黄素纳米粒的最佳工艺为：聚合物浓度4％,乳化剂TPGS浓度0．03％,超声时间8min,搅拌时间6h。以此工艺制备的载药纳米粒外形圆整光滑,粒度分布较为均匀,平均粒径为189．7nm,包封率为86．2％,载药量为7．45％。     

超临界CO2抗溶剂法制备紫杉醇缓释微球

采用超临界流体强制分散溶液技术,以D,L-聚乳酸和D,L-聚乳酸-聚乙二醇共聚物为载体材料,分别制备了紫杉醇缓释微球.通过扫描电镜、激光粒度仪检测微球外形及粒径分布;紫外吸光度法测量其载药量和包封率,恒温振荡透析法检测药物的体外释放性能;MTT法检测载药微球对Hela细胞的抑制作用.实验表明,两种载体的缓释微球球形度均较好,表面光滑,平均粒径较小,且粒径分布较窄.以聚乳酸和共聚物为载体的缓释微球载药量分别为5.4%±0.3%和5.3%±0.4%,包封率分别为51%±3%和45%±3%;药物释放呈缓释模式,共聚物载药微球药物释放速率较快.MTT法检测结果表明,载药微球对Hela细胞的增殖有明显抑制,共聚物载药微球对细胞增殖抑制更为明显.     

氧氟沙星PLGA微囊的制备、表征和影响包封率的因素

氧氟沙星在眼科临床广泛应用,本研究以氧氟沙星作为模型药物,采用水/油/水(w/o/w)的复乳化和溶剂扩散技术制备氧氟沙星聚乳酸-聚乙醇酸(PLGA)微囊,对影响包封率的工艺参数如药物浓度、PLGA使用量、初乳复乳的搅拌速率进行研究,并对微囊的粒径、表面电位和表面形态的理化性能进行了表征。测试结果表明,根据优化工艺制备的氧氟沙星PLGA微囊的平均粒径511.9±14.6nm,zeta电位-17.97±0.80mV,包封率54.2%,载药量1.94%。包封率随PLGA使用量、初乳搅拌速率的增加而上升,随内水相药物体积和浓度的增加而下降。通过优化的水/油/水(w/o/w)复乳化和溶剂扩散技术制备氧氟沙星PLGA载药微囊的粒度分布窄,载药量和包封率适中,具有较好的临床应用前景。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to