FTA-环介导等温扩增技术直接提取变异链球菌DNA的效果评价

背景:变异链球菌是龋病的重要病原菌,及时检测变异链球菌水平对龋病的早发现、早治疗有重要意义。目的:建立并评价FTA-环介导等温扩增(loop-mediated isothermal amplification,LAMP)技术直接提取变异链球菌DNA的应用效果。方法:①制备含有ATCC标准菌株变异链球菌的菌悬液,接种于脑心浸出液培养基,充分混匀后按10倍梯度稀释成7种浓度(4.2×10^(7),4.2×10^(6),4.2×10^(5),4.2×10^(4),4.2×10^(3),4.2×10^(2),4.2×10 CFU/mL),每个稀释级做2个平行对照,并增加无菌水作为空白对照;②分别采用FTA卡、常规煮沸法、试剂盒提取及裂解液提取4种方法直接提取菌株DNA,通过LAMP技术进行扩增,并进行特异性试验,比较4种提取方法的差异。结果与结论:①4种方法提取的DNA均满足LAMP扩增的要求;②特异性试验结果显示,只有变异链球菌才可特异扩增出靶基因;③裂解液提取法最低检测限为4.2×10^(3) CFU/mL,FTA卡提取法最低检测限为4.2×10^(4) CFU/mL,试剂盒提取法和常规煮沸法最低检测限分别为4.2×10^(6) CFU/mL和4.2×10^(7) CFU/mL;④4种提取方法其他方面的比较显示,试剂盒提取法的实验成本、步骤数和时间都是最高;其他3种方法步骤数一致,其中FTA卡所需仪器设备最少,常规煮沸法单次成本最低,裂解液提取法所需时间最少;FTA卡和裂解液提取法仅需少量菌即可提取成功,后者在时间方面优于FTA卡,但相较于FTA卡其单次成本高,所需设备多;⑤结果说明,该研究建立的FTA-LAMP技术具有操作简便、特异性强、灵敏度高、结果可视化等优势,有望为高效提取检测变异链球菌提供新途径。

Dynamic Interaction Analysis of Coupled Axial-Torsional-Lateral Mechanical Vibrations in Rotary Drilling Systems

Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and petroleum.To achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is required.This study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling equipment.The study specifically investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency stick-slip.These events not only hinder the efficiency of drilling but also lead to exhaustion and harm to the system’s components since they are difficult to be detected and controlled in real time.The study investigates the dynamic interactions of these vibrations,specifically in their high-frequency modes,usingfield data obtained from measurement while drilling.Thefindings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem performance.The obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control systems.Therefore,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect damage.Moreover,by exploiting thesefindings,the assessment of structural resilience in rotary drilling systems can be enhanced.Furthermore,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efficiency of rotary drilling systems in the petroleum industry.

Research status and prospects of the fractal analysis of metal material surfaces and interfaces

As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine properties.Fractal analysis has been used to characterize the shapes of metal materials at various scales and dimensions.Conventional methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and interfaces.However,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal materials.From the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear surfaces.The relationship between the fractal dimensions and properties of metal material surfaces and interfaces is summarized.Starting from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be developed.It is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.

Multilevel analysis of the central-peripheral-target organ pathway:contributing to recovery after peripheral nerve injury

Peripheral nerve injury is a common neurological condition that often leads to severe functional limitations and disabilities.Research on the pathogenesis of peripheral nerve injury has focused on pathological changes at individual injury sites,neglecting multilevel pathological analysis of the overall nervous system and target organs.This has led to restrictions on current therapeutic approaches.In this paper,we first summarize the potential mechanisms of peripheral nerve injury from a holistic perspective,covering the central nervous system,peripheral nervous system,and target organs.After peripheral nerve injury,the cortical plasticity of the brain is altered due to damage to and regeneration of peripheral nerves;changes such as neuronal apoptosis and axonal demyelination occur in the spinal cord.The nerve will undergo axonal regeneration,activation of Schwann cells,inflammatory response,and vascular system regeneration at the injury site.Corresponding damage to target organs can occur,including skeletal muscle atrophy and sensory receptor disruption.We then provide a brief review of the research advances in therapeutic approaches to peripheral nerve injury.The main current treatments are conducted passively and include physical factor rehabilitation,pharmacological treatments,cell-based therapies,and physical exercise.However,most treatments only partially address the problem and cannot complete the systematic recovery of the entire central nervous system-peripheral nervous system-target organ pathway.Therefore,we should further explore multilevel treatment options that produce effective,long-lasting results,perhaps requiring a combination of passive(traditional)and active(novel)treatment methods to stimulate rehabilitation at the central-peripheral-target organ levels to achieve better functional recovery.

深度FTA能缓解双边贸易摩擦吗?

随着世界各国对贸易的干预次数逐年增多,全球发生贸易摩擦的风险不断上升,严重影响了国际贸易的发展。梳理GTA数据库2009—2020年的贸易摩擦数据发现,各国对贸易领域的干预大多出于贸易保护目的;频繁发起贸易摩擦的国家也容易招致来自他国的贸易摩擦,存在着明显的“俱乐部效应”;反倾销等贸易救济措施对贸易摩擦的代表性逐年降低。理论分析和基于深度贸易协定数据库的实证研究表明,深度自由贸易协定(FTA)可以通过确立与完善争端解决机制、缩小国家间的经济增长速度差异,以及建立更密切的经贸合作关系等机制降低双边贸易摩擦的概率与频次。国家特征异质性分析显示,深度FTA对双边贸易摩擦的缓解作用受到“俱乐部效应”“、意大利面碗效应”和美国“长臂管辖”的异质性影响。研究结果对中国降低遭遇贸易摩擦风险,坚持扩大高水平对外开放,以及加快实施自贸区提升战略,构建面向全球的高标准自由贸易区网络具有重要启示。

中国与厄瓜多尔自由贸易协定(FTA)的贸易效应研究——基于GTAP动态递归的模拟分析

2023年5月,中国与厄瓜多尔签署自由贸易协定,中厄FTA将对两国双边贸易产生重要影响。通过分析中国与厄瓜多尔的贸易现状及竞争与互补关系,运用动态递归GTAP模型模拟分析中厄FTA的贸易效应。研究发现,中国与厄瓜多尔双边贸易规模逐年上升,两国贸易互补性较强。FTA的关税减让将促进中国与厄瓜多尔双边贸易增长,降低技术性贸易壁垒、提升贸易便利化水平对两国贸易的影响更显著,且FTA更有利于中方扩大对厄方的出口。中厄双方需加快推进FTA各项条款的生效及实施,中方应增加进口厄方的资源型产品,扩大对其出口和直接投资。

基于故障树分析法(FTA)的阿尔塔什水利枢纽电气二次系统可靠性设计

以新疆阿尔塔什水利枢纽为背景,介绍了可靠性理论在电气二次系统设计中的工程应用,重点阐述了可靠性分析方法、可靠性框图、可靠性数学模型的分析使用,并对电气二次系统可靠性设计的基本思路和工程实现进行探讨。

安全评价系列讲座 第八讲 故障树分析（Fault Tree Analysis，FTA）（下）

3故障树定性分析 故障树分析,包括定性分析和定量分析两种方法.在定性分析中,主要包括最小割集、最小径集和重要度分析.限于篇幅,以下仅介绍定性分析中的最小割集和最小径集.

FTA卡保存对虾传染性皮下和造血组织坏死病毒DNA洗脱方法的优化

传染性皮下和造血组织坏死病毒(infectious hypodermal and haematopoietic necrosis virus,IHHNV)是危害虾类健康养殖的重要病原,为寻找一种快捷保存及分离IHHNV DNA的方法,为后续研究提供完整的核酸材料,选用FTA(flinders technology associates)卡为保存介质,以FTA纯化试剂、TE(Tris-EDTA)缓冲液及去离子水为基础洗脱液,设计7种FTA卡黏附DNA洗脱方法,通过荧光定量PCR检测方法检验不同核酸洗脱分离效果及最低的点膜核酸量。结果显示,于4 mm2的FTA卡上,点样体积为2.5μL,用洗脱液作为模板时,最低点膜核酸浓度需要1.47×104copies/μL以上,可获得最佳的检测灵敏度和100%检出率的洗膜方法为50μL TE缓冲液于95℃下浸洗5 min;用膜片做模板,点膜核酸浓度需要1.82×103copies/μL以上,室温(20~25℃)条件下,用FTA纯化试剂洗脱3次,再用TE缓冲液洗脱2次,洗脱时间均为5 min,可获得最佳的检测灵敏度和100%的准确度。以FTA卡保存对虾白斑综合征病毒(white spot syndrome virus,WSSV)、虾肝肠胞虫(Enterocytozoon hepatopenaei,EHP)、虾十足目虹彩病毒1(Decapod iridescent virus 1,DIV1)、偷死野田村病毒(covert mortality noda virus,CMNV)、致急性肝胰腺坏死副溶血弧菌(Vibrio parahaemolyticus,VpAHPND)核酸,测试所建洗脱方法的效果,证实了该方法对其他虾类病原核酸的洗脱具有通用性。该研究给出了FTA卡保存和洗脱IHHNV DNA的适用性方案,为野外对虾样品采集、病毒核酸样品跨区域传递的保存和运输条件提供了科学数据。

基于FMEA和FTA的VLCC翼型风帆装置风险分析

为了保证VLCC翼型风帆装置的安全有效运行,开展基于FMEA和FTA方法的风帆系统风险分析,以设计工作流程为主线,分别判断风帆在各工况下机械、结构、电气、液压等方面潜在的失效模式、原因和后果,评估每个失效模式的可能性、严重性和探测性水平,基于风险优先数RPN判定失效模式的风险程度,制定高风险项的安全防控措施。基于故障树方法,以“无法紧急降帆”为顶事件,逐层分析分析其故障原因,确定不同事件的逻辑关系,构建故障树,针对每个基本事件制定防控措施。

Frequency Time Analysis (FTAN) and Moment Tensor Inversion Solutions from Short Period Surface Waves in Cameroon (Central Africa)

Short period surface waves generated by a local earthquake recorded by broadband seismometers at distances of about 186 to 778 km from the earthquake’s epicenter located in Cameroon (Central Africa) were processed for group velocity maps and dispersion waveforms using the frequency time analysis (FTAN) method. The resulting group velocity fundamental modes of the extracted Rayleigh and Love waves were used for a joint amplitude spectral and P polarity inversion using moment tensor inversion. The corresponding group velocity dispersion curves, the residual as a function of depth, the amplitude spectra and the moment tensor solutions of the regions from the epicenter to the different stations up to a depth of about 10 km were obtained.

基于FMEA和FTA的火炮随动系统可靠性分析

针对某型火炮随动系统的故障数据,对火炮随动系统进行可靠性分析。采用故障模式与影响分析(failure modes and effect analysis,FMEA),通过统计存在的故障模式及原因分析,得到造成火炮随动系统故障的主要原因,提出针对性的改善措施;根据FMEA结果,建立火炮随动系统故障树,计算火炮随动系统故障的最小割集,将其分为6类,针对不同的底事件故障类别提出改善措施。结果表明:该分析可为提高火炮随动系统的可靠性提供数据支撑,为火炮随动系统的设计和预防维修提供理论依据。

基于CBR和FTA的直升机故障诊断专家系统设计

直升机各个系统之间交联关系非常复杂,而当前国内直升机外场故障诊断主要依靠维修人员经验,难以快速准确地进行故障定位,严重影响直升机的维护和使用。基于相关问题,对以往型号中积累的经验进行深入研究,形成故障诊断所需的知识库,建立基于案例推理(CBR)和故障树(FTA)的直升机故障诊断专家系统,并在实际工作中得到应用。该系统充分利用以往积累的经验和知识,以期提升故障诊断的效率,减轻维修人员的工作负担。

Social-ecological perspective on the suicidal behaviour factors of early adolescents in China:a network analysis

Background In early adolescence,youth are highly prone to suicidal behaviours.Identifying modifiable risk factors during this critical phase is a priority to inform effective suicide prevention strategies.Aims To explore the risk and protective factors of suicidal behaviours(ie,suicidal ideation,plans and attempts)in early adolescence in China using a social-ecological perspective.Methods Using data from the cross-sectional project‘Healthy and Risky Behaviours Among Middle School Students in Anhui Province,China',stratified random cluster sampling was used to select 5724 middle school students who had completed self-report questionnaires in November 2020.Network analysis was employed to examine the correlates of suicidal ideation,plans and attempts at four levels,namely individual(sex,academic performance,serious physical llness/disability,history of self-harm,depression,impulsivity,sleep problems,resilience),family(family economic status,relationship with mother,relationship with father,family violence,childhood abuse,parental mental illness),school(relationship with teachers,relationship with classmates,school-bullying victimisation and perpetration)and social(social support,satisfaction with society).Results In total,37.9%,19.0%and 5.5%of the students reported suicidal ideation,plans and attempts in the past 6 months,respectively.The estimated network revealed that suicidal ideation,plans and attempts were collectively associated with a history of self-harm,sleep problems,childhood abuse,school bullying and victimisation.Centrality analysis indicated that the most influential nodes in the network were history of self-harm and childhood abuse.Notably,the network also showed unique correlates of suicidal ideation(sex,weight=0.60;impulsivity,weight=0.24;family violence,weight=0.17;relationship with teachers,weight=-0.03;school-bullying perpetration,weight=0.22),suicidal plans(social support,weight=-0.15)and suicidal attempts(relationship with mother,weight=-0.10;parental mental llness,weight=0.61).Conclusions This study identified the correlates of suicidal ideation,plans and attempts,and provided practical implications for suicide prevention for young adolescents in China.Firstly,this study highlighted the importance of joint interventions across multiple departments.Secondly,the common risk factors of suicidal ideation,plans and attempts were elucidated.Thirdly,this study proposed target interventions to address the unique influencing factors of suicidal ideation,plans and attempts.

Screening biomarkers for spinal cord injury using weighted gene co-expression network analysis and machine learning

Immune changes and inflammatory responses have been identified as central events in the pathological process of spinal co rd injury.They can greatly affect nerve regeneration and functional recovery.However,there is still limited understanding of the peripheral immune inflammato ry response in spinal cord inju ry.In this study.we obtained microRNA expression profiles from the peripheral blood of patients with spinal co rd injury using high-throughput sequencing.We also obtained the mRNA expression profile of spinal cord injury patients from the Gene Expression Omnibus(GEO)database(GSE151371).We identified 54 differentially expressed microRNAs and 1656 diffe rentially expressed genes using bioinformatics approaches.Functional enrichment analysis revealed that various common immune and inflammation-related signaling pathways,such as neutrophil extracellular trap formation pathway,T cell receptor signaling pathway,and nuclear factor-κB signal pathway,we re abnormally activated or inhibited in spinal cord inju ry patient samples.We applied an integrated strategy that combines weighted gene co-expression network analysis,LASSO logistic regression,and SVM-RFE algorithm and identified three biomarke rs associated with spinal cord injury:ANO10,BST1,and ZFP36L2.We verified the expression levels and diagnostic perfo rmance of these three genes in the original training dataset and clinical samples through the receiver operating characteristic curve.Quantitative polymerase chain reaction results showed that ANO20 and BST1 mRNA levels were increased and ZFP36L2 mRNA was decreased in the peripheral blood of spinal cord injury patients.We also constructed a small RNA-mRNA interaction network using Cytoscape.Additionally,we evaluated the proportion of 22 types of immune cells in the peripheral blood of spinal co rd injury patients using the CIBERSORT tool.The proportions of naive B cells,plasma cells,monocytes,and neutrophils were increased while the proportions of memory B cells,CD8^(+)T cells,resting natural killer cells,resting dendritic cells,and eosinophils were markedly decreased in spinal cord injury patients increased compared with healthy subjects,and ANO10,BST1 and ZFP26L2we re closely related to the proportion of certain immune cell types.The findings from this study provide new directions for the development of treatment strategies related to immune inflammation in spinal co rd inju ry and suggest that ANO10,BST2,and ZFP36L2 are potential biomarkers for spinal cord injury.The study was registe red in the Chinese Clinical Trial Registry(registration No.ChiCTR2200066985,December 12,2022).

基于FTA方法的某型飞机起落架故障诊断

针对某型飞机起落架的一例典型故障,根据其工作原理图,采用故障树分析法(Fault Tree Analysis,FTA)对故障进行分析、诊断,建立了以故障现象为顶事件的故障树及故障结构函数,得到了故障现象对应的所有基本事件。再结合某单位统计的此类故障基本事件的先验概率,通过重要度计算得到了该故障现象的失效概率,制定了故障诊断流程,为该型飞机此类故障的高效诊断、分析、维护提供依据与参考。

FMECA and FTA Methods of Reliability Analysis for Oil and Gas Pipeline Robot

In this paper,FMECA and FTA methods are presented for oil and gas Pipeline Robot in order to improve the reliability.Take a crawler pipeline cleaning robot as the research object.According to the robot′s variable working environment,high failure rate and short service life,in order to reduce the probability of its failure,and to extend its use time limit under the premise of being able to adapt to the complex working environment,and reduce maintenance cost of failure.To realize this purpose,FMECA analysis is fristly proposed,by which obtain the failure modes,causes and effects of each component mechanism,and identify the component mechanism with high risk and failure rate.Secondly,FTA is developed to establish the fault tree model of Cleaning and diameter changing mechanism,retain the underlying fault and the cause of its failure.Simulation results are carried out to illustrate the effectiveness of this proposed method and improvement measures to improve the reliability of the robot.

Advances in microfluidic-based DNA methylation analysis

DNA methylation has been extensively investigated in recent years,not least because of its known relationship with various diseases.Progress in analytical methods can greatly increase the relevance of DNA methylation studies to both clinical medicine and scientific research.Microflu-idic chips are excellent carriers for molecular analysis,and their use can provide improvements from multiple aspects.On-chip molecular analysis has received extensive attention owing to its advantages of portability,high throughput,low cost,and high efficiency.In recent years,the use of novel microfluidic chips for DNA methylation analysis has been widely reported and has shown obvious superiority to conventional methods.In this review,wefirst focus on DNA methylation and its applications.Then,we discuss advanced microfluidic-based methods for DNA methylation analysis and describe the great progress that has been made in recent years.Finally,we summarize the advantages that microfluidic technology brings to DNA methylation analysis and describe several challenges and perspectives for on-chip DNA methylation analysis.This review should help researchers improve their understanding and make progress in developing microfluidic-based methods for DNA methylation analysis.

A Review on Sources,Extractions and Analysis Methods of a Sustainable Biomaterial:Tannins

Condensed and hydrolysable tannins are non-toxic natural polyphenols that are a commercial commodity industrialized for tanning hides to obtain leather and for a growing number of other industrial applications mainly to substitute petroleum-based products.They are a definite class of sustainable materials of the forestry industry.They have been in operation for hundreds of years to manufacture leather and now for a growing number of applications in a variety of other industries,such as wood adhesives,metal coating,pharmaceutical/medical applications and several others.This review presents the main sources,either already or potentially commercial of this forestry by-materials,their industrial and laboratory extraction systems,their systems of analysis with their advantages and drawbacks,be these methods so simple to even appear primitive but nonetheless of proven effectiveness,or very modern and instrumental.It constitutes a basic but essential summary of what is necessary to know of these sustainable materials.In doing so,the review highlights some of the main challenges that remain to be addressed to deliver the quality and economics of tannin supply necessary to fulfill the industrial production requirements for some materials-based uses.

Telomerase-related advances in hepatocellular carcinoma:A bibliometric and visual analysis

BACKGROUND As a critical early event in hepatocellular carcinogenesis,telomerase activation might be a promising and critical biomarker for hepatocellular carcinoma(HCC)patients,and its function in the genesis and treatment of HCC has gained much attention over the past two decades.AIM To perform a bibliometric analysis to systematically assess the current state of research on HCC-related telomerase.METHODS The Web of Science Core Collection and PubMed were systematically searched to retrieve publications pertaining to HCC/telomerase limited to“articles”and“reviews”published in English.A total of 873 relevant publications related to HCC and telomerase were identified.We employed the Bibliometrix package in R to extract and analyze the fundamental information of the publications,such as the trends in the publications,citation counts,most prolific or influential writers,and most popular journals;to screen for keywords occurring at high frequency;and to draw collaboration and cluster analysis charts on the basis of coauthorship and co-occurrences.VOSviewer was utilized to compile and visualize the bibliometric data.RESULTS A surge of 51 publications on HCC/telomerase research occurred in 2016,the most productive year from 1996 to 2023,accompanied by the peak citation count recorded in 2016.Up to December 2023,35226 citations were made to all publications,an average of 46.6 citations to each paper.The United States received the most citations(n=13531),followed by China(n=7427)and Japan(n=5754).In terms of national cooperation,China presented the highest centrality,its strongest bonds being to the United States and Japan.Among the 20 academic institutions with the most publications,ten came from China and the rest of Asia,though the University of Paris Cité,Public Assistance-Hospitals of Paris,and the National Institute of Health and Medical Research(INSERM)were the most prolific.As for individual contributions,Hisatomi H,Kaneko S,and Ide T were the three most prolific authors.Kaneko S ranked first by H-index,G-index,and overall publication count,while Zucman-Rossi J ranked first in citation count.The five most popular journals were the World Journal of Gastroenterology,Hepatology,Journal of Hepatology,Oncotarget,and Oncogene,while Nature Genetics,Hepatology,and Nature Reviews Disease Primers had the most citations.We extracted 2293 keywords from the publications,120 of which appeared more than ten times.The most frequent were HCC,telomerase and human telomerase reverse transcriptase(hTERT).Keywords such as mutational landscape,TERT promoter mutations,landscape,risk,and prognosis were among the most common issues in this field in the last three years and may be topics for research in the coming years.CONCLUSION Our bibliometric analysis provides a comprehensive overview of HCC/telomerase research and insights into promising upcoming research.