猪肺炎支原体环介导等温扩增检测方法的建立

目的建立检测猪肺炎支原体(Mycoplasma hyopneumoniae,Mh)的环介导等温扩增(Loop-mediated isothermal am-plification,LAMP)方法。方法根据GenBank中登录的猪肺炎支原体的核苷酸序列,设计4条特异性引物,用外引物进行PCR反应,对内外引物浓度、dNTP+和MgSO4浓度及Bst DNA聚合酶用量等进行优化,建立猪肺炎支原体LAMP检测方法,并对该方法进行特异性和敏感性验证。结果内外引物浓度分别为0.5和0.20 pmol/μl,dNTP+浓度为0.5 mmol/L,MgSO4浓度为3.75 mmol/L,Bst DNA聚合酶用量为8.0和9.6 U时,LAMP反应效果较好;应用该方法检测多杀性巴氏杆菌、猪胸膜肺炎放线杆菌、肺炎双球菌、支气管败血波氏杆菌、副猪嗜血杆菌和链球菌均呈阴性;当猪肺炎支原体的拷贝数低于3时,检测不到该病原体。结论已建立了猪肺炎支原体LAMP检测方法,该方法特异性较好,敏感性较高。     

Isothermal crystallization kinetics and subsequent melting behavior of β‐nucleated isotactic polypropylene/graphene oxide composites with different ordered structure

The effects of ordered structure on isothermal crystallization kinetics and subsequent melting behavior of β‐nucleated isotactic polypropylene/graphene oxide (iPP/GO) composites were studied using differential scanning calorimetry. The ordered structure status was controlled by tuning the fusion temperature (T_f). The results showed that depending on the variation of crystallization rate, the whole T_f range could be divided into three regions: Region I (T_f > 179 °C), Region II (170 °C ≤ T_f ≤ 179 °C) and Region III (T_f < 170 °C). As T_f decreased from Region I to Region III, the crystallization rate would increase substantially at two transition points, due to the variation of the ordered structure status. Calculation of Avrami exponent n indicated that the ordered structure induced the formation of two‐dimensional growing crystallites rather than three‐dimensional growing crystallites. Moreover, in the case of isothermal crystallization, the ordered structure effect (OSE) can also greatly increase the relative content of β‐phase (β_c). In Region II, OSE took place, resulting in evident increase of β_c, achieving 92.4% at maximum. The variation of the isothermal crystallization temperature (T_iso) had little influence on the T_f range (Region II) of the OSE. The higher T_f in Region II was more favorable for the formation of higher β_c. The ordered structure was favorable for the improvement of the nucleating efficiency of β‐nucleating agent (β‐NE), and was more effective for the improvement of lower β‐NE. © 2018 Society of Chemical Industry     

Non‐isothermal crystallization kinetics of Al2O3‐YAG amorphous ceramic coating deposited via plasma spraying

Crystallization kinetics of the newly developed Al₂O₃‐Y₃Al₅O₁₂ (YAG) amorphous ceramic coating fabricated by atmospheric plasma spraying (APS) were investigated via differential scanning calorimetry (DSC) under non‐isothermal conditions. The phase compositions and microstructure of the as‐sprayed coating were characterized by X‐ray diffraction (XRD) and Scanning electron microscopy (SEM). The glass transition temperature T_g, the onset temperature of crystallization T_c and the peak temperature of crystallization T_p presented heating rate dependence. The related kinetic parameters of activation energies (E_g, E_c, E_p) and Avrami exponents (n) were quantified using various methods including Kissinger, Augis–Bennett, Ozawa and Matusita–Sakka, etc., to understand the phase transition mechanism and crystallization process in depth. A series of parameters including devitrification interval ΔT, thermal stability (T_c, E_c), nucleation resistance E_c/RT_g and fragility index F were quantified in order to evaluate the nucleation mechanism, crystallization behavior and thermal stability of Al₂O₃‐YAG amorphous ceramic coating. Excellent thermal stability was witnessed in the studied coating. Furthermore, the YAG crystalline phases can be reasonably controlled and independently precipitated from the amorphous matrix via proper annealing.     

等温核酸放大技术在重金属检测方面的应用

等温核酸放大技术是一种可以实现重金属污染物痕量分析的高灵敏性检测方法,在分析检测中有着广泛且重要的作用。本文综述了几种不同的等温核酸放大技术及其在重金属检测方面的应用,阐述分析了各方法的检测原理,为之后建立更加灵敏、快速、准确的检测方法提供了参考。虽然等温核酸放大技术目前主要停留在实验室阶段,并且检测目标有限,但是由于该技术的高灵敏性、特异性以及与其他学科紧密的联系性,具有潜在的应用前景。     

焦粉与秸秆混合成型燃料等温燃烧特性研究

利用自制的恒温热重实验装置对焦粉与秸秆混合成型燃料进行等温燃烧试验,分别研究了焦粉与秸秆掺混比为90∶10、85∶15、80∶20、75∶25、70∶30时,在800 ℃、900 ℃、1 000 ℃下的燃烧特性,并根据等温燃烧法得到成型燃料的反应动力学参数。结果表明:温度上升和秸秆比例增加都会使燃料的燃烧速度加快,燃尽时间显著减少;5种混合成型燃料等温燃烧的反应级数在0.9~2.0;反应活化能和指前因子都随着秸秆掺混比例的增加而降低,从25%增加到30%时两者会有一个大幅度降低的突变。     

等温马氏体转变动力学模型的修正

自促发形核机制对于等温马氏体转变的解释是正确的.但是现有几种动力学模型尚存在一些不妥之处.文中给出一种物理意义更为明确的修正模型.     

粗糙金属表面接触的热应力场和等温应力场研究

粗糙金属表面接触表层中的等温应力与热应力场对金属表面的边界膜成膜,磨损与疲劳机理都有重要影响。但由于问题的复杂性,人们以往在研究粗糙金属表面接触性能时,大多只注意到研究压力场和温度场而忽略了应力场。本文首次在考虑了微凸体之间互相影响的基础上研究了弹性粗糙平面滑块与刚性光滑平面接触的等温应力与热应力场。目的是为进一步研究边界膜成膜机理,磨损,疲劳及表面胶合机理提供理论依据。     

Real-Time Duplex Applications of Loop-Mediated AMPlification (LAMP) by Assimilating Probes

Isothermal nucleic-acid amplification methods such as Loop-Mediated isothermal AMPlification (LAMP) are increasingly appealing alternatives to PCR for use in portable diagnostic system due to the low cost, weight, and power requirements of the instrumentation. As such, interest in developing new probes and other functionality based on the LAMP reaction has been intense. Here, we report on the development of duplexed LAMP assays for pathogen detection using spectrally unique Assimilating Probes. As proof of principle, we used a reaction for Salmonella enterica as a model coupled with a reaction for λ-phage DNA as an internal control, as well as a duplexed assay to sub-type specific quarantine strains of the bacterial wilt pathogen Ralstonia solanacearum. Detection limits for bacterial DNA analyzed in individual reactions was less than 100 genomic equivalents in all cases, and increased by one to two orders of magnitude when reactions were coupled in duplexed formats. Even so, due to the more robust activity of newly available strand-displacing polymerases, the duplexed assays reported here were more powerful than analogous individual reactions reported only a few years ago, and represent a significant advance for incorporation of internal controls to validate assay results in the field.     

PA1212-b-PEG嵌段共聚物的合成和非等温结晶动力学研究

采用DSC方法研究了PA1212-b-PEG在不同降温速率下的结晶过程,并利用Avrami方程研究了其非等温结晶动力学。在非等温结晶过程中,随着降温速率的增大,结晶温度向低温偏移。综合利用Avrami方程得到Avrami指数为4,说明结晶是以异相成核,三维生长。