纳豆菌液体发酵转化黄芩苷和汉黄芩苷的工艺研究

探索研究纳豆菌液体发酵黄芩药材制备黄芩素和汉黄芩素的工艺,利用纳豆菌所产生的活性酶对黄芩苷和汉黄芩苷进行生物转化,以提高黄芩中黄芩素和汉黄芩素的含量。通过考察不同碳源、氮源及无机盐的种类和浓度、培养基pH、药材粉碎度、装液量、摇床转速、液料比、发酵时间等因素对发酵工艺的影响,以黄芩素和汉黄芩素的含量为评价指标,优选得到黄芩生物转化生成黄芩素和汉黄芩素的液体发酵最佳工艺为蛋白胨质量分数为1.0%,氯化钠0.05%,pH 6.0,黄芩药材粉碎过40目,装样量33%,摇床转速200 r·min^-1,液料比5 : 1,温度37 ℃,发酵6 d,黄芩药材中黄芩苷的转化率为97.6%,汉黄芩苷转化率97.0%。验证试验表明该工艺稳定可行,为黄芩素和汉黄芩素的工业化生产提供数据参考。     

Topology Optimization of Piezoelectric Energy Harvesters for Enhanced Open-Circuit Voltage Subjected to Harmonic Excitations

Energy harvesting devices made of piezoelectric material are highly anticipated energy sources for power wireless sensors. Tremendous efforts have been made to improve the performance of piezoelectric energy harvesters (PEHs). Noticeably, topology optimization has shown an attractive potential to design PEHs with enhanced energy conversion efficiency. In this work, an alternative yet more practical design objective was considered, where the open-circuit voltage of PEHs is enhanced by topologically optimizing the through-thickness piezoelectric material distribution of plate-type PEHs subjected to harmonic excitations. Compared to the conventional efficiency-enhanced designs, the open-circuit voltage of PEHs can be evidently enhanced by the proposed method while with negligible sacrifice on the energy conversion efficiency. Numerical investigations show that the voltage cancellation effect due to inconsistent voltage phases can be effectively ameliorated by optimally distributed piezoelectric materials.     

Research on Hyperparameter Optimization of Concrete Slump Prediction Model Based on Response Surface Method

In this paper, eight variables of cement, blast furnace slag, fly ash, water, superplasticizer, coarse aggregate, fine aggregate and flow are used as network input and slump is used as network output to construct a back-propagation (BP) neural network. On this basis, the learning rate, momentum factor, number of hidden nodes and number of iterations are used as hyperparameters to construct 2-layer and 3-layer neural networks respectively. Finally, the response surface method (RSM) is used to optimize the parameters of the network model obtained previously. The results show that the network model with parameters obtained by the response surface method (RSM) has a better coefficient of determination for the test set than the model before optimization, and the optimized model has higher prediction accuracy. At the same time, the model is used to evaluate the influencing factors of each variable on slump. The results show that flow, water, coarse aggregate and fine aggregate are the four main influencing factors, and the maximum influencing factor of flow is 0.875. This also provides a new idea for quickly and effectively adjusting the parameters of the neural network model to improve the prediction accuracy of concrete slump.     

金钗石斛遗传多样性研究的ISSR-PCR反应体系建立与优化

目的：对影响金钗石斛ISSR-PCR扩增效果的一些因素进行优化,为进一步研究其遗传多样性奠定基础。方法：通过筛选引物并设定影响金钗石斛ISSR反应诸因子的不同浓度,检测ISSR不同反应体系的扩增效果;通过分析非特异性条带的产生原因并进行条件优化,建立金钗石斛ISSR稳定可靠的反应体系。结果：金钗石斛较适宜的ISSR-PCR反应条件为：10 lμPCR反应体系,含5～15 ng模板DNA、2.0 mmol/L Mg^2＋、0.20 mmol/L dNTP、0.6～0.75 U Taq DNA聚合酶、1.0μmol/L引物。较适宜的退火温度为46～62℃。结论：Taq酶质量、DNA模板品质、退火温度等对ISSR反应结果具有较大影响。所建立的金钗石斛ISSR反应体系具有标记位点清晰、反应系统稳定、检测多态性能力较强、重复性好等特点,可用于金钗石斛的遗传多样性研究。     

住院患者血乳酸和血氨的检测流程优化及质量提升

目的 探讨同济大学附属同济医院住院患者乳酸和血氨项目检测结果阳性率高的原因,并制定改进措施,提高乳酸和血氨检测的准确性.方法 以乳酸>2.2 mmol/L或血氨>30μmol/L为阳性,分别统计同济大学附属同济医院2019年1—6月门诊、急诊、住院和住院急诊患者样本乳酸及血氨项目的总检测数、检测结果阳性率以及检验流程各...     

“一键启动”流程优化在缩短急性缺血性脑卒中患者静脉溶栓时间中的应用

目的 探讨“一键启动”流程优化在缩短急性缺血性脑卒中患者静脉溶栓时间中的应用效果。方法 选择2020年1-12月笔者所在医院收治的急性缺血性脑卒中静脉溶栓患者86例为研究对象,其中2020年1-6月入院进行静脉溶栓的41例为对照组,2020年7-12月入院进行静脉溶栓的45例为观察组。对照组采用常规抢救流程,观察组采用“一键启动”流程优化进行干预。比较2组入院至见到神经内科医生的时间（door to physician,DTP）、入院至实验室检查出报告时间（door to laboratory,DTL）、入院至溶栓用药时间（door to needle time,DNT）、入院至完成CT检查的时间（door to imaging,DTI）、美国国立卫生研究院卒中量表（national institute of health stroke scale,NIHSS）评分与改良RANKIN量表（modified Rankin scale,MRS）评分。结果 观察组DTP、DTL、DTI、DNT均明显短于对照组（Z=-8.506,P<0.001;Z=-6.750,P<0.001;Z...     

响应面法结合满意度函数优化白囊耙齿菌发酵培养基

采用响应面法和满意度函数,以期望值作为响应值,提高白囊耙齿菌发酵的菌丝体干重以及胞内多糖、甘露醇、腺苷和蛋白质的含量.通过单因素法优化白囊耙齿菌发酵培养基中的碳、氮源和无机盐,然后进行部分因子试验考察培养基组分对菌株发酵的影响,并应用中心组合设计试验优化培养基,获得最佳培养基配方(%):乳糖2.94,酵母浸粉1.5,牛肉膏1.5,KH2PO4·3H2O 0.065,MgSO4·7H2O 0.06,NaCl 0.000 8,VB1 0.028 9.模型预测最佳培养基配方下白囊耙齿菌的发酵期望值为0.624,3次验证试验平均值为0.617 7,是优化前的5.27倍,与模型预测值间的误差为1.01%.     

樱花多糖提取工艺的优化及抗氧化性研究

目的:通过正交试验优化樱花多糖的提取工艺,对樱花多糖的抗氧化功能进行了相关的研究,为樱花多糖保健功能的研究提供试验依据。方法:通过正交设计优化樱花多糖的提取工艺,用蒽酮-硫酸法测定不同提取条件下多糖的含量,并对其进行抗氧化性试验和自由基的清除试验。结果与结论:通过对试验结果进行分析,最优工艺为3 g干燥的樱花花瓣置于烧杯中,加蒸馏水240 m L,在90℃的水浴锅中提取3 h,过滤,离心,得上清液。各种浓度的樱花多糖提取液均能够有效地清除超氧阴离子自由基(O2-·),且随着浓度的增大,其清除能力逐渐增强。浓度为70.5μg·L-1多糖提取液的清除率为58.82%。     

海洋真菌Penicillium sp.产抗肿瘤天然产物brefeldin A的发酵优化研究

目的 对海洋来源真菌Penicillium sp.产抗肿瘤天然产物brefeldin A的发酵优化,以期获得高产率目标化合物。方法 运用单因素实验设计,重点考察了培养方式、发酵培养基组成 (如碳源、氮源、盐度等)以及培养条件 (温度、摇床转速)等因素。结果 最佳发酵条件为：马铃薯200 g/L,麦芽糖10 g/L,淀粉20 g/L,海盐15 g/L,28 ℃, 摇床转速160 r/min,培养14天。结论 在该发酵条件下,brefeldin A的实际产量达到40 mg/L,较优化前提高了近10倍。     

Formulation Optimization of Paclitaxel Carried by PEGylated Emulsions Based on Artificial Neural Network

PURPOSE: To develop paclitaxel carried by injectable PEGylated emulsions, an artificial neural network (ANN) was used to optimize the formulation--which has a small particle size, high entrapment efficiency, and good stability--and to investigate the role of each ingredient in the emulsion. METHODS: Paclitaxel emulsions were prepared by a modified ethanol injection method. A computer optimization technique based on a spherical experimental design for three-level, three factors [soybean oil (X1), PEG-DSPE (X2) and polysorbate 80 (X3)] were used to optimize the formulation. The entrapment efficiency of paclitaxel (Y1) was quantified by HPLC; the particle size of the emulsions (Y2) was measured by dynamic laser light scattering and the stability of paclitaxel emulsions was monitored by the changes in drug concentration (Y3) and particle size (Y4) after storage at 4 degrees C. RESULTS: The entrapment efficiency, particle size and stability of paclitaxel emulsions were influenced by PEG-DSPE, polysorbate 80, and soybean oil. Paclitaxel emulsions of small size (262 nm), high entrapment efficiency (96.7%), and good stability were obtained by the optimization. CONCLUSIONS: A novel formulation for paclitaxel emulsions was optimized with ANN and prepared. The contribution indices of each component suggested that PEG-DSPE mainly contributes to the entrapment efficiency and particle size of paclitaxel emulsions, while polysorbate 80 contributes to stability.