Establishment of a Loop-mediated Isothermal Amplification Method for Rice Bacterial Leaf Brown Spot Disease

Rice bacterial leaf brown spot disease caused by Pseudomonas syringae pv.syringae(Pss)is a major disease on rice.In recent years,Pss has emerged worldwide,seriously affecting rice production.It is very important to establish a rapid detection method of Pss for the diagnosis and prevention of this disease.In order to robust and accurately diagnose the rice bacterial leaf brown spot disease in the field and laboratory,an assay system for the Pss was developed in this study,and the specific sequence of hrcN was used as the target,based on loop-mediated isothermal amplification(LAMP).The best detection system was MgSO 48 mmol·L^(-1),Bst DNA polymerase 8 U,dNTP 1.4 mmol·L^(-1),the ratio of internal and outer primers was 2:1,the reaction temperature was 63℃,the reaction time was 45 min,and the lowest sensitivity was 104 CFU·mL^(-1).This results provided an accurate and robust method for laboratory and field diagnosis of bacterial leaf brown spot disease of rice.

Establishment of Reverse-transcription Loopmediated Isothermal Amplification Method for Detection of Wheat Streak Mosaic Virus

A reverse-transcription loop-mediated isothermal amplification （RT-LAMP） method was established for the detection of wheat streak mosaic virus （WSMV）. Ac-cording to the conservative regions of the genes that encode the coat protein of WSMV, 2 pairs of primers were designed. Final y, the 1st pair of primers was select-ed through the specificity test. The sensitivity test showed the sensitivity of RT-LAMP method was 10 times higher than that of RT-PCR. In addition, the amplifica-tion of target gene could be judged visual y from the presence of fluorescence （cal-cein） in the final reaction system. The RT-LAMP method, established in this study, was rapid, easy, specific and sensitive. Moreover, it did not require sophisticated equip-ment. The RT-LAMP was suitable for the rapid detection of WSMV.

Auditory Hopf Amplification Revealed by an Energy Method

We report on the auditory Hopf amplification contributed by the electrical energy of the hair cell during its bundle deflecting. An energy method to calculate the active force is adopted according to the electrical energy consumption of the hair cell. After some experimental data was analyzed and simulated, we find that the electrical energy determines the value of the active force and enlarges the mechanical response of the hair bundle. This amplification is controlled by the cell voltage and makes the sensor a Hopf vibrator with hearing nonlinear characteristics. A velocity-dependent active force derived previously from the force-gating channel operation strongly reinforces our conclusion.

A new two-step variational model for multiplicative noise removal with applications to texture images

Multiplicative noise removal problems have attracted much attention in recent years.Unlike additive noise,multiplicative noise destroys almost all information of the original image,especially for texture images.Motivated by the TV-Stokes model,we propose a new two-step variational model to denoise the texture images corrupted by multiplicative noise with a good geometry explanation in this paper.In the first step,we convert the multiplicative denoising problem into an additive one by the logarithm transform and propagate the isophote directions in the tangential field smoothing.Once the isophote directions are constructed,an image is restored to fit the constructed directions in the second step.The existence and uniqueness of the solution to the variational problems are proved.In these two steps,we use the gradient descent method and construct finite difference schemes to solve the problems.Especially,the augmented Lagrangian method and the fast Fourier transform are adopted to accelerate the calculation.Experimental results show that the proposed model can remove the multiplicative noise efficiently and protect the texture well.

Rapid and Visualized Detection Method of Canine Parvovirus Using Loop-Mediated Isothermal Amplification

[Objective] To develop a rapid and visualized detection method using loop-mediated isothermal amplification （LAMP）, improve the detection rate of canine parvovirus （CPV） and reduce the testing cost. [ Method] According to the conserved regions of the VP2 gene of CPV, six primers were designed to amplify the special DNA sequences by LAMP. In addition, the reaction conditions of LAMP were optimized, and the sensitivity, specificity, repeatability and stability were verified. [ Result] The optimal reaction time of the LAMP method for CPVwas 60 min. The products obtained by LAMP had high specificity without cross-reaction with other generic viruses. The sensitivity of the LAMP was 100 times higher than that of PCR. [ Conclusion] The LAMP method for detecting CPV has high practical value. It has many advantages such as high specificity, high sensitivity, simple operation, low cost and rapid analysis, and it does not require special equipment. Therefore, this method is more suitable for the detection of CPV.

Preparation of Microcapsules Containing Aqueous Solution of Azur B with Melting Dispersion Cooling Method and Application to DNA Amplification Detector

Microcapsules containing the aqueous solution of Azur B of a water soluble dye were prepared with the melting dispersion cooling method and applied to the amplification detector of plant DNA. Paraffin wax with melting temperature of 75°C was used as the shell material. In the experiment, the aqueous solution (W) of Azur B as the core material was dispersed in the melted paraffin wax (O) to form the (W/O) emulsion and then, the (W/O) emulsion was dispersed in the silicon oil (O’) as the continuous phase to form the (W/O)/O’ emulsion at 85°C. After formation of the (W/O)/O’ emulsion, the microcapsules were prepared by cooling the (W/O)/O’ emulsion to 50°C. The microcapsules were prepared by changing the concentration of oil soluble surfactant in the (W/O) emulsion and the volume of the (W/O) emulsion in the (W/O)/O’ emulsion. The microencapsulation efficiency increased with the concentration of oil soluble surfactant and finally became 100% under the optimum conditions. Furthermore, the microcapsules were melted down at temperature of 85°C to reveal the sharp thermal responsibility and to release the aqueous solution of Azur B. As a result, it was found that the microcapsules were able to be applied to the amplification detector of plant DNA by utilizing the reaction between DNA and Azur B.

Rapid detection of Pseudomonas aeruginosa by cross priming amplification

Pseudomonas aeruginosa(PA)is an opportunistic pathogen of humans and animals and a common source of nosocomial infections especially of the respiratory tract.Pseudomonas aeruginosa is also a major bacterial disease of poultry and in particular,eggs and newly hatched chicks.In this study,we developed a simple,accurate and rapid molecular detection method using cross priming amplification(CPA)with a nucleic acid test strip to detect P.aeruginosa.The assay efficiently amplified the target gene within 45 min at 62℃only using a simple water bath.The detection limit of the method was 1.18x 102 copiesμL^-1 for plasmid DNA and 4.4 CFU mL^-1 for bacteria in pure culture,and was 100 times more sensitive than conventional PCR.We screened 83 clinical samples from yellow-feather broiler breeder chickens and hospitalized/treated dogs and cats using CPA,PCR and traditional culture methods.The positive sample ratios were 15.3%(13/83)by CPA,13.3%(11/83)by PCR and 12.1%(10/83)by the culture method.The established CPA method has significant advantages for detecting P.aeruginosa.The method is easy to use and possesses high specificity and sensitivity without the requirements of complicated experimental equipment.The PA-CPA assay is especially fit for outdoor and primary medical units and is an ideal system for the rapid detection and monitoring of P.aeruginosa.

Temperature-dependent photoluminescence on organic inorganic metal halide perovskite CH_3NH_3Pb I_(3-)Cl_ prepared on ZnO/FTO substrates using a two-step method

Temperature-dependent photoluminescence characteristics of organic-inorganic halide perovskite CH3NH3Pb I3-xClx films prepared using a two-step method on ZnO/FTO substrates were investigated. Surface morphology and absorption characteristics of the films were also studied. Scanning electron microscopy revealed large crystals and substrate coverage. The orthorhombic-to-tetragonal phase transition temperature was-140 K. The films＇ exciton binding energy was 77.6 ± 10.9 meV and the energy of optical phonons was 38.8 ± 2.5 meV. These results suggest that perovskite CH3NH3Pb I（3-x）Clx films have excellent optoelectronic characteristics which further suggests their potential usage in perovskitebased optoelectronic devices.

Amplification of in-plane seismic ground motion by group cavities in layered half-space (Ⅱ): with saturated poroelastic soil layers

As the continuation study on amplification of in-plane seismic ground motion by underground group cavities in layered half-space, this study extends to the case of poroelastic half-space with dry poroelastic and saturated poroelastic soil layers. The influence of poroelastic layers on the amplification of seismic ground motion is studied both in frequency domain and time domain using indirect boundary element method （IBEM）. It is shown that for the example of a saturated poroelastic site in Tianjin under the excitation of Taft wave and E1 Centro wave, the amplification of seismic ground motion in poroelastic case is slightly smaller than that in the elastic case, and the amplification of PGA （peak ground acceleration） and its PRS （peak response spectrum）.. can be increased up to 38.8% and 64.6%; the predominant period of response spectra in poroelastic case becomes shorter to some extent compared with that in the elastic case. It is suggested that the effect of underground group cavities in poroelastic half-space on design seismic ground motion should be considered.

Amplification of in-plane seismic ground motion by group cavities in layered half-space (Ⅰ)

Amplification of in-plane seismic ground motion by underground group cavities in layered half-space is studied both in frequency domain and time domain by using indirect boundary element method （IBEM）, and the effect of cavity interval and spectrum of incident waves on the amplification are studied by numerical examples. It is shown that there may be large interaction between cavities, and group cavities with certain intervals may have significant amplification to seismic ground motion. The amplification of PGA （peak ground acceleration） and its PRS （peak response spectrum） can be increased up to 45.2% and 84.4%, for an example site in Tianjin, under the excitation of Taft wave and E1 Centro wave; and group cavities may also affect the spectra of the seismic ground motion. It is suggested that the effect of underground group cavities on design seismic ground motion should be considered.

Seismic ground amplification induced by box-shaped tunnels

The growing use of underground structures,specifically to facilitate urban transportation,highlights the need to scrutinize the effects of such spaces on the seismic ground response as well as the surrounding buildings.In this regard,the seismic ground amplification variations in the vicinity of single and twin box-shaped tunnels subjected to SV waves have been investigated by the finite difference method.To evaluate the effects,generalizable dimensionless diagrams based on the results of parametric numerical analysis considering factors such as variations in the tunnels′depth,the distances between the tunnels,tunnel lining flexibility,and input wave frequency,have been presented.In addition,to assess the effects of underground box-shaped tunnels on the response spectrum of the ground surface,seven selected accelerograms have been matched based on a specific design spectrum for the stiff soil condition of Eurocode 8(CEN,2006).The results underline the significant amplification effect of the box-shaped tunnels on the ground motions,specifically in the case of horizontal twin tunnels,which should be given more attention in current seismic design practices for surface structures.

Applying the Dynamic Two-Step Method to Forecast Remaining Oil Distribution of Lower Series ,Xiaermen Oilfield

The distribution of remaining oil is often described qualitatively. The remaining oil distributed in the whole reservoir is calculated according to the characteristics of the space distribution of the saturation of remaining oil. Logging data are required to accomplish this. However, many such projects cannot be completed. Since the old study of remaining oil distribution could not be quantified efficiently, the ＂dynamic two-step method＂ is presented. Firstly, the water cut of every flow unit in one well at one time is calculated according to the comprehensive water cut of a single well at one time. Secondly, the remaining oil saturation of the flow unit of the well at one time is calculated based on the water cut of the flow unit at a given time. The results show that ＂dynamic two-step method＂ has characteristics of simplicity and convenience, and is especially suitable for the study of remaining oil distribution at high water-cut stage. The distribution of remaining oil presented banding and potato form, remaining oil was relatively concentrated in faultage neighborhood and imperfect well netting position, and the net thickness of the place was great. This proposal can provide an effective way to forecast remaining oil distribution and enhance oil recovery, especially applied at the high water-cut stage.

The convergence ball and error analysis of the two-step Secant method

Under the assumption that the nonlinear operator has Lipschitz continuous divided differences for the first order,we obtain an estimate of the radius of the convergence ball for the two-step secant method.Moreover,we also provide an error estimate that matches the convergence order of the two-step secant method.At last,we give an application of the proposed theorem.

Solution of Nonlinear Integro Differential Equations by Two-Step Adomian Decomposition Method (TSAM)

The Adomian decomposition method (ADM) can be used to solve a wide range of problems and usually gets the solution in a series form. In this paper, we propose two-step Adomian Decomposition Method (TSAM) for nonlinear integro-differential equations that will facilitate the calculations. In this modification, compared to the standard Adomian decomposition method, the size of calculations was reduced. This modification also avoids computing Adomian polynomials. Numerical results are given to show the efficiency and performance of this method.

放大电路静态在固定式偏置放大电路中的分析

论文主要从固定式偏置共射极放大电路静态工作点的分析方法出发,详细介绍了静态工作点分析常用的图解法和解析法,并对两种方法进行了对比,提出了两种方法的适用性和静态工作点选取的一般原则,为电子信息、电气自动化、机电工程、汽车、电力、城轨运营等专业的教学与学习提供了参考。

深加工益生菌产品中常用7种乳杆菌的快速鉴定

目的探讨适用于复杂基质中益生菌产品的DNA提取方法,并通过鉴定7种常见的乳杆菌,比较产品标签标示与实际添加乳杆菌种类的一致性。方法本研究采用了3种不同的DNA提取方法,分别为十六烷基三甲基溴化铵(cetyltrimethylammonium bromide,CTAB)法、磁珠法深加工产品基因组DNA抽提试剂盒(磁珠法)和Ezup柱式深加工产品基因组DNA抽提试剂盒(柱式法);通过测定DNA浓度、纯度以及利用16SrDNA V3/V4基因扩增技术评估DNA质量。此外合成嗜酸乳杆菌、德氏乳杆菌保加利亚亚种、罗伊氏粘液乳杆菌、植物乳植杆菌、干酪乳酪杆菌、鼠李糖乳酪杆菌和副干酪乳酪杆菌特异性引物探针,利用实时荧光定量聚合酶链式反应(real-time fluorescence quantitative PCR,qPCR)技术验证方法的特异性、灵敏度和重复性,进一步对市售益生菌产品进行乳杆菌种类的鉴定。结果综合3个DNA质量评价方法,使用CTAB法提取的DNA质量较高,纯度在1.7~2.1之间,质量浓度大于25ng/mL,且16SrDNAV3/V4基因扩增的循环数阈值(cycle threshold,Ct)值均小于35,符合后续qPCR扩增要求;相比之下,柱式法除了饼干类产品DNA纯度为1.96±0.13,浓度为79.07±2.15,扩增Ct值为22.67±3.09能够达到要求外,提取的其他产品DNA和磁珠法提取的DNA无法同时满足3个DNA评价方法要求且重复性较差。本研究所使用的引物和探针对目标乳杆菌有明显的特异性扩增,灵敏度范围为0.0100~1.0000ng/μL和10^(3)~10^(4)CFU/mL,且重复性良好[相对标准偏差(relative standard deviation,RSD)≤3.02%]。检测的20批市售产品中,6批产品未检出标示的乳杆菌种类,存在标示与实际检出菌种不符的情况。结论CTAB法因其较高的适应性和低成本,在提取复杂基质中益生菌产品的DNA时表现更优,结合qPCR方法能有效实现产品中乳杆菌种水平鉴定;然而针对干酪乳酪杆菌的检出限需要进一步研究开发更为灵敏的引物和探针。

具有力放大功能的压电俘能器建模与性能分析

为提升压电俘能器的能量转换效率,将压电堆栈耦合到力放大框架结构中,构建了具有力放大功能的压电俘能器。基于压电效应本构方程,对单独压电堆栈进行了理论建模、有限元仿真与分析。基于欧拉-伯努利梁原理,建立了框架结构的力放大系数理论模型,采用Sobol’s敏感性分析方法确定了敏感力放大系数的框架几何参数,应用遗传算法结合有限元建模对力放大框架进行了结构优化。基于最优结构的力放大框架,建立了压电俘能器的集总参数理论模型并进行了数值分析。结果表明,在非谐振激励下该压电俘能器的输出电压有效值和输出功率最大值分别为3.022 V和543.375μW,分别是单独压电堆栈输出电压有效值和输出功率最大值的7.74倍和58.5倍。相比于单独压电堆栈,该压电俘能器能显著提升非谐振激励下的输出电压和输出功率。

拟静力法在基坑抗震中的应用探讨

基坑工程作为项目建设的重要环节,其稳定性关系城市安全。随着地下枢纽、立体交通等理念的提出,部分基坑呈现规模大、周期长、周边环境复杂等特点。此时,不能简单将其视为一种临时结构,需要考虑地震等偶发灾害的影响。为了计算地震工况下的安全性,将拟静力法引入到基坑的稳定性分析中。汇总归纳了现有规范中的拟静力法,基于各规范的特点讨论了折减系数和放大系数取值原则。通过时程分析法,从剪力、弯矩和位移等方面进行验证。结果表明:在应用拟静力法时,应该考虑基坑工程的特点。区别于边坡工程,基坑工程加速度小于或接近地表设计地震。因此,加速度放大系数可取为1。折减系数取0.25时,拟静力法计算结果略大于时程分析法,可以达到包络设计的目的。

深水导管架平台波浪动力响应及参数敏感性分析

考虑到300 m级导管架平台的自振周期与自升式平台极为接近,自升式平台的波浪动力响应分析方法在理论上可应用于深水导管架平台,但应用前需要进行参数敏感性分析,采用SACS软件建立300 m级导管架平台有限元模型,结合JONSWAP波浪谱、利用线性叠加法构造满足高斯性条件的随机波浪;基于时域分析法,进行在随机波浪载荷下的结构动力响应分析;采用Winterstein/Jensen方法计算平台基底剪力和倾覆力矩的最可能最大值,以及动力放大系数;对波浪瞬态变化、模拟步长和时长、随机种子等参数对动力放大系数进行敏感性分析,结果表明,动力放大系数对波浪瞬态变化较为敏感、对模拟步长和时长,以及随机种子极为敏感。采用Winterstein/Jensen方法进行深水导管架平台动力响应分析时,基于敏感性分析得出的参数可获得更合理、准确的动力放大系数。

醋酸卡泊芬净生产工艺的技术改进

介绍了醋酸卡泊芬净制备过程,通过小试探索对主流工艺进行改进,通过丙酮打浆、溶剂洗涤、一锅法合成卡泊芬净醋酸水溶液、氮气干燥等工艺技术改进,实现了工业化公斤级生产并且成功完成了工业公斤级别的工艺放大,极大地降低了产业的生产成本,提高了产品合成收率,可以为更大级别的工业生产放大提供一定的技术支撑。