Response surface optimization of high dose pellets by extrusion and spheronization

A radial basket-type extruder and a serrated plate spheronizer were used to prepare spherical pellets containing approx. 80% active drug. A response surface experimental design was employed to address the effects of altering microcrystalline cellulose concentration, water concentration, spheronizer speed and spheronizing time on pelletization of this low density drug. Response surfaces were adequately described by quadratic equations which contained significant interaction terms for two of three measured product characteristics. Optimum ingredient concentrations and process conditions were selected from the response surface equations. Product subsequently manufactured under these optimum conditions met expectations. This results in a well-characterized, reproducible process for manufacturing smooth pellets with adequate potency to provide a 500 mg dose in a ‘0’ elongated capsule.     

Progress in 3-D treatment planning for photon beam therapy

The purpose of this report is to study the feasibility of improving dose distributions using non-coplanar photon beams from a linear accelerator. Non-coplanar beams may enter the patient in any arbitrary configuration. This type of treatment technique requires a three-dimensional (3-D) planning system. Clinical examples are used to illustrate the general problems in 3-D treatment planning, and the potential improvement over coplanar beam treatments. Features of a treatment planning system for 3-D planning are discussed.     

前列地尔脂质体制备工艺条件优化

目的:对制备前列地尔脂质体的工艺条件进行优化。方法:采用滴入法制备前列地尔脂质体,并以脂质体粒径及包封率为指标进行工艺条件优化。结果:前列地尔脂质体最佳制备工艺条件为乙醇处方用量12·5%、搅拌速度600r·min-1、滴入时间45min、缓冲液pH4·05;制备的脂质体粒径范围60～200nm,包封率为88·0%～90·5%。结论:滴入法制备前列地尔脂质体方便,可靠;制备工艺合理,可行。     

赤雹总黄酮提取优化工艺考察

目的：优选赤雹总黄酮的提取工艺。方法：以赤雹总黄酮的提出量为评价指标,以提取次数、提取时间、固液比为考察因素,采用正交试验法优选赤雹总黄酮的提取工艺。结果：优化的提取条件为70％乙醇回流,提取2次,每次1．5h,固液比为1：8。结论：此工艺操作简便,重复性好,稳定可行。     

医学双语教学教材优化探讨

双语教学是实现高等教育国际化的重要途径,教材是双语教学中的核心要素.为了解决教材建设滞后的问题,必须根据教学要求和实际情况对各种类型的双语教材采取优化措施,以使其能够对教学改革起到促进作用.本文对不同类型的医学双语教材进行了分析,提出了相应的优化建议.     

薄层色谱溶剂系统的最优化方法——Ⅵ.均匀设计法的再探讨

就第Ⅱ报及第Ⅴ报提出的用于选取薄层色谱最佳溶剂系统的均匀设计法进行了进一步的改进及实验验证,使其更趋完善。结果表明,该法不仅适用于已知混合物,而且适用于未知混合物,是一种比较简捷、快速且行之有效的方法。     

反相高效液相色谱溶剂系统优化的正交设计法

在高效液相色谱(HPLC)中,通过改变流动相组成来调节色谱系统的选择性,以适应各种分析要求,但如何改变流动相组成以适应分析要求往往是一项费时而又复杂的工作。目前,国内外已报道了许多HPLC分析条件优化的方法,尤其是溶剂系统优化方法。本文     

摆动从动杆盘状凸轮机构的运动设计——同时考虑压力角和最小曲率半径的优化设计

本文对摆动从动杆盘状凸轮机构的最大压力角和最小曲率半径问题进行了详细的讨论。根据优化原理,同时考虑许用压力角和最小曲率半径,对摆动从动杆盘状凸轮机构进行了最优化设计。在仅给出摆杆运动规律、摆杆最大摆角和相应凸轮转角的情况下,直接确定凸轮的最小基圆半径、摆杆长度和摆杆初始位置角。     

Comparison of the biomechanical 3D efficiency of different brace designs for the treatment of scoliosis using a finite element model

The biomechanical influence of thoraco-lumbo-sacral bracing, a commonly employed treatment in scoliosis, is still not fully understood. The aim of this study was to compare the immediate corrections generated by different virtual braces using a patient-specific finite element model (FEM) and to analyze the most influential design factors. The 3D geometry of three patients presenting different types of curves was acquired with a multi-view X-ray technique and surface topography. A personalized FEM of the patients’ trunk and a parametric model of a virtual custom-fit brace were then created. The installation of the braces on the patients was simulated. The influence of 15 design factors on the 3D correction generated by the brace was evaluated following a design of experiments simulation protocol allowing computing the main and two-way interaction effects of the design factors. A total of 12,288 different braces were tested. Results showed a great variability of the braces effectiveness. Of the 15 design factors investigated, according to the 2 modalities chosen for each one, the 5 most influential design factors were the position of the brace opening (posterior vs. anterior), the strap tension, the trochanter extension side, the lordosis design and the rigid shell shape. The position of the brace opening modified the correction mechanism. The trochanter extension position influenced the efficiency of the thoracic and lumbar pads by modifying their lever arm. Increasing the strap tension improved corrections of coronal curves. The lordosis design had an influence in the sagittal plane but not in the coronal plane. This study could help to better understand the brace biomechanics and to rationalize and optimize their design.     

全胸腔镜肺叶切除手术操作流程及技巧的优化:北京大学人民医院经验

目的 总结北京大学人民医院全胸腔镜肺叶切除手术的操作流程和技巧的优化改进经验.方法 2006年9月至2010年8月连续开展全胸腔镜肺叶切除手术408例,男214例,女194例,平均年龄58.6岁.实体肿瘤平均最大径30.1 mm.手术采用双腔气管插管全身麻醉,健侧单肺通气.胸腔镜观察口选择第7或8肋间腋后线,长1.5 cm;辅助操作切口选择在肩胛下角线第7或8肋间,长1.5 cm;主操作口选择在第4或第5肋间腋前线,长约4 cm,无需放置开胸器,不牵开肋骨.全部操作过程完全在胸腔镜下完成.术者位于病人前侧,双手分别握持吸引器和电凝钩,在主操作口内进行操作;助手位于病人背侧,使用卵圆钳经辅助操作口帮助牵拉显露.基本操作顺序与传统开胸肺叶切除相同.肺癌病人均清扫纵隔淋巴结:肿瘤位于右侧,清扫2、4、3A、3P、7、8、9、10组淋巴结;左侧清扫3、5、6、7、8、9、10组淋巴结,必要时清扫第4组淋巴结.结果 全组手术顺利,围手术期死亡1例,无严重并发症发生.平均手术时间195 min,平均术中出血249 ml.术后病理良性疾病86例,恶性疾病322例.全组中转开胸35例,中转开胸率8.6%.术后轻微并发症48例,并发症发生率11.8%.术后平均带胸管时间7.9天,术后平均住院天数10.9天.结论 全胸腔镜肺叶切除手术操作难度较高,开展此项手术应具备5个方面条件:(1)较清晰的胸腔镜设备,(2)良好的术野显露,(3)熟练的镜下血管解剖分离技巧,(4)能将血管和支气管置入缝合切开器内,(5)纵隔淋巴结清扫技术.掌握正确的操作流程及一些关键技巧,可以缩短学习曲线.