Optimal Planar Flow Network Designs for Tissue Engineered Constructs with Built-in Vasculature

Convective delivery of nutrients is important to enhance mass transport within tissue engineered (TE) products. Depending on the target tissue, an ideal TE product will have an integrated microvasculature that will eliminate mass transport limitations that can occur during product growth in vitro and integration in vivo. A synthetic approach to develop microvasculature involves development of network designs with efficient mass transfer characteristics. In this paper, utilizing a planar bifurcating network as a basis, we develop an approach to design optimal flow networks that have maximum mass transport efficiency for a given pressure drop. We formulated the optimization problem for a TE skin product, incorporating two types of duct flow, rectangular and square, and solved using a generalized reduced gradient algorithm. Under the conditions of this study, we found that rectangular ducts have superior mass transport characteristics than square ducts. Microvascular area per volume values obtained in this work are significantly greater than those reported in the literature. We discuss the effect of network variables such as porosity and generations on the optimal designs. This research forms the engineering basis for the rational development of TE products with built-in microvasculature and will pave the way to design complex flow networks with optimal mass transfer characteristics.     

运用中药药对配伍优化消渴病中医防治方案临床研究

目的:运用秦伯未处方公式,观察选用施今墨药对配伍辨证治疗2型糖尿病的疗效和对中医方案的影响。 方法:纯中医治疗组(A组)辨证予以“药对”组合化裁; 对照治疗组(B组)采用阿卡波糖,三餐时服用,空白对照组(C组),无任何药物干预,仅与饮食运动配合。每组各30例,疗程5个月后,观察三组餐前,餐后血糖及糖化血红蛋白的变化。 结果:三组临床疗效比较,A组临床疗效总有效率为50.00%,B组总有效率为53.33%,C组总有效率16.67%。A组与B组总有效率比较,差异无统计学意义(P>0.05)。A组、B组与C组比较,差异有统计学意义(P<0.05)。三组患者中医症候疗效比较,A组总有效率70.00%; B组总有效率46.67%。C组总有效率23.33%。A组疗效优于B组(P<0.05)。A组、B组与C组比较,差异有统计学意义(P<0.05)。药对使用情况,苍术对白术频率最高。单味药物,苍术使用最多。药对中,健脾、化湿、疏肝、活血在治疗中占有重要地位。提示消渴病机主要是中焦湿浊,肝郁脾虚,气滞血瘀。结论:按秦伯未处方公式思路,选用施今墨药对配伍出来的治疗糖尿病中药方案能有效缓解症状并降糖,但在改善症状方面要优于降血糖本身。     

Optimization of fermentation process of Cordyceps militaris and antitumor activities of polysaccharides in vitro

The influence of medium composition and cultural conditions on simultaneous yield of mycelia, intracellular polysaccharide, adenosine, and mannitol by Cordyceps militaris CGMCC 2909 was investigated with desirability functions in this study. An optimization strategy based on the desirability function approach, together with response surface methodology (RSM) has been used to optimize medium composition, and the optimal medium was obtained via the desirability as follows: yeast extract 10.33 g/L, sucrose 27.24 g/L, KH₂PO₄ 5.60 g/L and the optimal culture conditions are initial pH 6, 25°C, rotation speed 150 r/minute, inoculum size 4%(v/v), and medium capacity 40 mL/250 mL. Under these conditions, the yield of mycelia, intracellular polysaccharide, adenosine and mannitol reached 12.19 g/L, 0.6 g/L, 61.84 mg/L, and 1.38 g/L, respectively, and the D value was 0.77. Furthermore, the polysaccharides showed significant antitumor activities against HeLa and HepG2 in vitro in a dose-dependent manner in 72 hours. At a concentration of 1000 mg/mL, the inhibition rate of polysaccharides was 92.38% and 98.79%. The IC50 for HeLa and HepG2 were 70.91 μg/mL and 97.63 μg/mL, respectively.     

Utilizing mixer torque rheometer in the prediction of optimal wet massing parameters for pellet formulation by extrusion/spheronization

In this study, we aimed to optimize theophylline pellet formulations using a two-factor three-level full-factorial design (3²) by monitoring the concentration of two pellet excipients, polyvinyl pyrrolidone K30 (PVP) binder solution (X1) and the hydrophilic excipient mannitol (X2). Their impact on pellet characteristics (responses) were evaluated. Increasing PVP concentration in the binder solution resulted in an increase in the wet mass torque value. The effect of mannitol, however, was antagonistic. Moreover, the pellet particle size was significantly influenced by the level of mannitol, PVP solution, and quadratic effect of mannitol. Mannitol significantly antagonized the pellet particle size. Furthermore, increased mannitol concentrations significantly enhanced drug dissolution rate from the pellets, whereas PVP concentration in the binder solution significantly reduced the drug dissolution rate. In conclusion, wet granulations can be controlled by monitoring the composition of the binder solution and pellet composition.     

右美托咪定在颅脑肿瘤手术中的应用

目的探讨右美托咪定在丙泊酚复合芬太尼麻醉下行颅脑肿瘤手术中的优化作用。方法拟行择期手术的小脑幕上肿瘤患者42例,ASAⅠ或Ⅱ级,随机均分为两组。麻醉诱导前,右美托咪定组(D组)于20min内静脉输注右美托咪定负荷剂量1μg/kg,随后静脉输注0.4μg·kg-1·h-1维持至手术结束;对照组(C组)静脉输注等量生理盐水。以丙泊酚、芬太尼、顺阿曲库铵完成麻醉诱导,气管插管。术中以BIS为指导,七氟醚静吸复合维持麻醉。记录麻醉诱导前(T0)、气管插管时(T1)、打开硬脑膜(T2)、关上硬脑膜(T3)、拔除气管插管即刻(T4)时MAP、HR、颅内压(ICP)的变化。记录呼气末七氟醚浓度和术中芬太尼总量、手术时间、术后拔管时间、术后止吐药的使用情况。结果 T1~T3时C组ICP,T1~T4时MAP明显高于T0时和D组,T4时两组ICP明显低于T0时,且D组明显低于C组(P0.01);T1~T4时D组HR明显慢于T0时和C组(P0.01)。D组芬太尼总量、呼气末七氟醚浓度明显低于C组,拔管时间明显短于C组(P0.01)。D组血管活性药物使用率明显低于C组(P0.01)。结论在颅脑肿瘤手术中,右美托咪定在稳定血流动力学、控制颅内压及术后复苏方面显著优化了常用的丙泊酚复合芬太尼全麻方案,同时减少了阿片药物及吸入麻醉药物用量。     

Optimal needle design for minimal insertion force and bevel length

This research presents a methodology for optimal design of the needle geometry to minimize the insertion force and bevel length based on mathematical models of cutting edge inclination and rake angles and the insertion force. In brachytherapy, the needle with lower insertion force typically is easier for guidance and has less deflection. In this study, the needle with lancet point (denoted as lancet needle) is applied to demonstrate the model-based optimization for needle design. Mathematical models to calculate the bevel length and inclination and rake angles for lancet needle are presented. A needle insertion force model is developed to predict the insertion force for lancet needle. The genetic algorithm is utilized to optimize the needle geometry for two cases. One is to minimize the needle insertion force. Using the geometry of a commercial lancet needle as the baseline, the optimized needle has 11% lower insertion force with the same bevel length. The other case is to minimize the bevel length under the same needle insertion force. The optimized design can reduce the bevel length by 46%. Both optimized needle designs were validated experimentally in ex vivo porcine liver needle insertion tests and demonstrated the methodology of the model-based optimal needle design.     

优化温针灸流程对不良事件发生及患者舒适度的影响

目的:观察优化温针灸流程对患者温针灸过程中不良事件发生及舒适度的影响。方法:选取行温针灸治疗的140例患者为研究对象,按随机数字表法分为观察组和对照组各70例。对照组采用传统纸片承接散灰,观察组使用锡纸圆杯代替传统纸片。结果:观察组无不良事件发生。对照组出现不良事件频率较高,其中灰烬跌落床单和灰烬跌落皮肤发生率与观察组比较,差异均有统计学意义(P<0.05)。观察组舒适度优于对照组,差异有统计学意义(P<0.05)。结论:优化温针灸流程在温针灸过程中能减少不良事件发生,提高患者的舒适度。     

绞股蓝提取物制备工艺研究

目的:研究出绞股蓝提取物,为绞股蓝产品研发提供实验数据。方法:建立绞股蓝提取物的化学评价方法;优化绞股蓝提取物的提取工艺,用化学评价方法分别对绞股蓝的乙醇浓度、料液比、提取时间、提取次数4个单因素进行考察,以L 9(34)正交表设计优化工艺,筛选出最佳提取工艺。结果:经单因素考察和正交优化得到绞股蓝提取物制备工艺为料液比为1∶8的70%乙醇,加热回流提取3次,每次45 min,绞股蓝总皂苷含量为0.1025 mg/mL,提取率为10.25%。结论:建立的化学评价方法可评价绞股蓝提取物;制备工艺能为绞股蓝产品研发提供依据。     

基于变区域搜索的改进遗传算法研究

针对基本遗传算法容易陷入局部最优解的缺点,提出了一种求解全局最优解的变区域搜索遗传算法。该算法以上一代最优解为导向,在它所在的随机局部区域内搜索,以提高当代最优解附近的搜索密度,加快遗传算法的收敛速度。基于标准函数的仿真测试研究表明,本算法能有效地减小进化代数和提高最优解的精度,尤其适合维数较多的函数寻优。