Separation and extraction of antimicrobial lipopeptides produced by Bacillus amyloliquefaciens ES-2 with macroporous resin

A new method for separation and extraction of antibiotic lipopeptides produced by Bacillus amyloliquefaciens ES-2 with macroporous resin was carried out in this study. Among widely used twelve macroporous resins, X-5 resin had the highest adsorption capacity in static and dynamic tests, its non-polarity and configuration were suited for the lipopeptides (surfactin and fengycin). Dynamic adsorption and desorption experiments were performed using a column packed with X-5 resin to obtain optimal conditions, with 30 g/L resin concentration, 0.5 BV/h feed flow rate, 80% aqueous ethanol at 1 BV/h elute flow rate as eluant agent, the total content of lipopeptides in final product was 79.5% (surfactin content was 33.2% while fengycin content was 23.4%), which had been improved about 150% compared with that of lipopeptide in fermentation broth. Because of its low cost, high efficiency, procedural simplicity and scale up ease, the adsorption–desorption method could be more efficient for the preparative separation and extraction of antibiotic lipopeptide than the conventional acid precipitation method, which could provide scientific references for antibiotic lipopeptide production.     

无机填料改性超高分子量聚乙烯性能研究

采用流动改性剂、偶联剂、无机填料等对超高分子量聚乙烯(UHMWPE)进行改性.旨在保持UHMWPE良好的耐磨、耐冲击等性能的基础上,提高材料的熔体流动性,以能通过注塑机注射成型.通过扫描电子显微镜及力学性能测试等确定其改性效果.结果表明,经改性的UHMWPE的熔体流动性有明显提高,但耐磨损性降低(摩擦系数增大).该改性UHMWPE被注塑成机械密封垫,经使用证明材料具有良好的加工性能,但耐磨损性有待进一步提高.     

无线温湿度采集系统的Linux驱动程序设计

为了解决传统的有线温湿度采集系统布线难、灵活性差等问题,设计了基于嵌入式Linux的无线温湿度采集系统.首先,进行了硬件方案的设计;其次,在此基础上设计了采集系统在嵌入式Linux下面的驱动程序.在该驱动程序中,编写了利用S3C2440的SPI1接口与nRF24L01之间进行标准SPI通信的驱动程序,解决了在模拟SPI时序时,嵌入式Linux的多任务处理特性而导致的延时不准确的问题.最后设计了采用双线程和信号量的Linux应用程序,并验证了该采集系统的准确性和可行性.     

Reliability Research on the Thermal Deformation and Stress of Metal Packaging With Low-Resistance Leads

Thermomechanical reliability of the metal packaging with low-resistance and high-electric current was discussed in this paper. Thermal deformations and stresses of packaging structures were studied by both experimental and numerical methods. Laser speckle interferometry was used as the experimental method to test the coefficient of thermal expansion of the metal composite leads and the thermal deformations of the entire packaging structures due to the temperature change from room-temperature to 150degC. ABAQUS/standard finite element (FE) code was used to simulate the thermal deformations and stresses of the packaging structures from room temperature to 150degC. The facts show that the results were in good agreement with those of experiments. It showed that the predicted thermal stresses and deformation in the working condition were qualitatively reliable. Moreover, the technique of elements deactivating and activating was used in FE analysis to simulate the manufacturing process of the packaging structures cooled from 779degC to room-temperature. Then the residual thermal deformations and stresses during the process were obtained.     

Scavenging and anti-fatigue activity of fermented defatted soybean peptides

Many bioactive peptides possess specific biological properties that make these potential ingredients of health-promoting foods. Increasing attention is being focused on physiologically active peptides derived from soybean proteins. In this study, soybean peptides were produced by fermentation of defatted soybean meal with Bacillus subtilis SHZ and purified by ultrafiltration and gel chromatogram. Free radical scavenging property and the effect on anti-fatigue of the peptides were evaluated in vitro and in vivo, respectively. Swimming endurance tests of mice were carried out after 20 days of soybean peptides administration (0, 100, 200, 400 mg/kg BW/day for control, low-dose, middle-dose and high-dose group, respectively). And the blood lactate and hepatic glycogen of mice were determined. Results showed that the purified peptides exhibited significant (P < 0.01) scavenging potencies on superoxide (62%) and hydroxyl (96%) at a concentration of 10 mg/ml. The average swimming time of the low-, middle- and high-dose group was increased by 20.91, 45.45 and 70% compared with that of control group, respectively. And administration with soybean peptides could significantly accelerate the clearance of blood lactate after mice swimming (P < 0.01). The hepatic glycogen storage of middle and high dose groups were obviously increased (P < 0.05). It suggested that the soybean peptides produced by fermentation could significantly alleviate physical fatigue of the mice.     

水平井参与下的油藏隔夹层描述技术及应用

油田开发中后期井间隔夹层分布预测成为油藏精细描述中不可或缺的研究内容,由于隔夹层导致的渗透差异成为影响剩余油分布的重要因素。针对复杂的、非均质性很强的油藏类型,仅依靠露头地质资料、有限的直井信息、地质经验难以精准、合理地表征复杂油藏中的薄隔夹层。本文充分利用水平井开发区丰富的水平井信息,提出一种新的直井与水平井联合的隔夹层描述新思路与新流程,引入了隔夹层敏感测井曲线的变化幅度参数值交会分析新技术,利用直井（段）的隔夹层识别、划分标准和地震构造面约束下的地层产状水平井曲线预测技术,构建出直井（段）与水平井的隔夹层等时对比格架、直井与水平井隔夹层测井响应关系,确定了水平井单井隔夹层类型和定量解释标准;探讨了水平井沿轨迹方向的隔夹层分布;综合多种信息和地质模型指导完成了水平井参与下的油藏隔夹层剖面对比分析、隔夹层平面展布规律的研究,验证和修正了前人基于直井（段）隔夹层解释结果、明显地提高了隔夹层预测精度,最后结合动态开发资料综合分析了在隔夹层控制下的油水运动过程以及剩余油分布富集特征,为后续油田开发方案的调整以及新井部署提供了有力的依据。     

高师院校无机化学实验教学改革初探

文章分析了目前高师院校无机化学实验课程教学中存在的各种问题,初步探讨了无机化学实验教学改革的必要性,改革内容包括课程教学内容、教学方法、教学手段等等。     

Conditional t-SNE: more informative t-SNE embeddings

Machine Learning - Dimensionality reduction and manifold learning methods such as t-distributed stochastic neighbor embedding (t-SNE) are frequently used to map high-dimensional data into a...     

Bilateral posteroventral pallidotomy in advanced Parkinson's disease in three patients

In this report, we describe the effect of staged bilateral posteroventral pallidotomy in three patients with advanced Parkinson's disease who were all of the young-onset type. Two patients had developed response fluctuations after the use of levodopa, with severe hypokinesia, painful dystonia, and rigidity in the "off" phase and violent dyskinesias in the "on" phase. One patient, in a continuous hypokinetic rigid state, was totally unresponsive to dopaminergic medication. All were at Hoehn and Yahr stage 5 in the "off" phase before surgery. After surgery, the hypokinetic state was reversed and dyskinesias were abolished in all patients. Hoehn and Yahr stages were 3 in the "off" phase postoperatively. Overall functional improvement was marked and lasting after follow-up for 7, 12, and 13 months, respectively. Complications were visual field deficit and transient central facial paresis, both in the same patient. Bilateral posteroventral pallidotomy can ameliorate response fluctuations, hypokinesia, rigidity, and painful dystonia in advanced Parkinson's disease.