奶牛乳房炎病原菌的分离和PCR方法快速鉴定

奶牛乳房炎是奶牛养殖场中最严重的疾病之一.为了确定奶牛乳房炎主要致病菌,本实验对采自养殖场临床乳房炎40个病例的乳样,用传统细菌培养方法分离奶牛乳房炎病原菌进行形态学鉴定;用纯化培养后细菌单菌落提取DNA作为模板,利用已报道的细菌通用引物,采用PCR方法进行分子鉴定.结果共分离得到10种主要致病菌,它们是嗜酸氧化硫硫杆菌,琼氏不动杆菌,农杆菌,蜡状芽孢杆菌,地衣芽胞杆菌,芽孢杆菌,大肠杆菌,克雷伯菌,假单胞菌,金黄色葡萄球菌.本研究成功建立了一种快速、特异性强的奶牛乳房炎致病菌的鉴定方法.     

《电气控制与PLC应用》项目教学法研究与实践

介绍了《电气控制与PLC应用》课程在高职类高校教学中采用项目驱动法改革的研究与项目设置。结合实验条件和学生实际能力设置了五个大的实验项目一将所要学习的知识点融入项目中进行教学。采用理论联系实际增强学生对知识的理解和掌握;采用教学做一体化提高学生的动手能力和设计能力。实践证明,通过《电气控制与PLC应用》课程的改革,提高了学生的学习兴趣和创新能力。     

分子印迹涂层的茉莉酸类植物激素固相微萃取应用

通过电化学方法制备以顺式-茉莉酮(CJ)为模板的分子印记聚3,4-乙烯二氧噻吩涂层(CJ-MI/PEDOT),与气相色谱(GC)联用,建立植物组织中茉莉酸类植物激素(JAs)的CJ-MI/PEDOT-GC分离分析方法,优化萃取条件如盐度、搅拌速率、萃取时间和萃取温度.方法检出限(LOD)为2. 0 ng m L-1,线性范围为8 1 000 ng·m L-1(R2=0. 992 1).该方法提高了PEDOT涂层对于目标物的选择性,已成功应用于植物组织中茉莉酸类植物激素的检测.     

Impact of cavitation on lesion formation induced by high intensity focused ultrasound

High intensity focused ultrasound(HIFU) has shown a great promise in noninvasive cancer therapy. The impact of acoustic cavitation on the lesion formation induced by HIFU is investigated both experimentally and theoretically in transparent protein-containing gel and ex vivo liver tissue samples. A numerical model that accounts for nonlinear acoustic propagation and heat transfer is used to simulate the lesion formation induced by the thermal effect. The results showed that lesions could be induced in the samples exposed to HIFU with various acoustic pressures and pulse lengths. The measured areas of lesions formed in the lateral direction were comparable to the simulated results, while much larger discrepancy was observed between the experimental and simulated data for the areas of longitudinal lesion cross-section. Meanwhile,a series of stripe-wiped-off B-mode pictures were obtained by using a special imaging processing method so that HIFUinduced cavitation bubble activities could be monitored in real-time and quantitatively analyzed as the functions of acoustic pressure and pulse length. The results indicated that, unlike the lateral area of HIFU-induced lesion that was less affected by the cavitation activity, the longitudinal cross-section of HIFU-induced lesion was significantly influenced by the generation of cavitation bubbles through the temperature elevation resulting from HIFU exposures. Therefore, considering the clinical safety in HIFU treatments, more attention should be paid on the lesion formation in the longitudinal direction to avoid uncontrollable variation resulting from HIFU-induced cavitation activity.     

Interaction between encapsulated microbubbles:A finite element modelling study

Theoretical studies on the multi-bubble interaction are crucial for the in-depth understanding of the mechanism behind the applications of ultrasound contrast agents(UCAs) in clinics. A two-dimensional(2 D) axisymmetric finite element model(FEM) is developed here to investigate the bubble–bubble interactions for UCAs in a fluidic environment. The effect of the driving frequency and the bubble size on the bubble interaction tendency(viz., bubbles' attraction and repulsion),as well as the influences of bubble shell mechanical parameters(viz., surface tension coefficient and viscosity coefficient)are discussed. Based on FEM simulations, the temporal evolution of the bubbles' radii, the bubble–bubble distance, and the distribution of the velocity field in the surrounding fluid are investigated in detail. The results suggest that for the interacting bubble–bubble couple, the overall translational tendency should be determined by the relationship between the driving frequency and their resonance frequencies. When the driving frequency falls between the resonance frequencies of two bubbles with different sizes, they will repel each other, otherwise they will attract each other. For constant acoustic driving parameters used in this paper, the changing rate of the bubble radius decreases as the viscosity coefficient increases,and increases first then decreases as the bubble shell surface tension coefficient increases, which means that the strength of bubble–bubble interaction could be adjusted by changing the bubble shell visco-elasticity coefficients. The current work should provide a powerful explanation for the accumulation observations in an experiment, and provide a fundamental theoretical support for the applications of UCAs in clinics.