Experimental study of the damage characteristics of rocks containing non-penetrating cracks under cyclic loading

The damage evolution process of non-penetrating cracks often causes some unexpected engineering disasters.Gypsum specimens containing non-penetrating crack(s)are used to study the damage evolution and characteristics under cyclic loading.The results show that under cyclic loading,the relationship between the number of non-penetrating crack(s)and the characteristic parameters(cyclic number,peak stress,peak strain,failure stress,and failure strain)of the pre-cracked specimens can be represented by a decreasing linear function.The damage evolution equation is fitted by calibrating the accumulative plastic strain for each cycle,and the damage constitutive equation is proposed by the concept of effective stress.Additionally,non-penetrating cracks are more likely to cause uneven stress distribution,damage accumulation,and local failure of specimen.The local failure can change the stress distribution and relieve the inhibition of non-penetrating crack extension and eventually cause a dramatic destruction of the specimen.Therefore,the evolution process caused by non-penetrating cracks can be regarded as one of the important reasons for inducing rockburst.These results are expected to improve the understanding of the process of spalling formation and rockburst and can be used to analyze the stability of rocks or rock structures.

Characterization of acute-on-chronic liver diseases: A multicenter prospective cohort study

BACKGROUND Acute-on-chronic liver disease(AoCLD)accounts for the majority of patients hospitalized in the Department of Hepatology or Infectious Diseases.AIM To explore the characterization of AoCLD to provide theoretical guidance for the accurate diagnosis and prognosis of AoCLD.METHODS Patients with AoCLD from the Chinese Acute-on-Chronic Liver Failure(ACLF)study cohort were included in this study.The clinical characteristics and outcomes,and the 90-d survival rate associated with each clinical type of AoCLD were analyzed,using the Kaplan-Meier method and the log-rank test.RESULTS A total of 3375 patients with AoCLD were enrolled,including 1679(49.7%)patients with liver cirrhosis acute decompensation(LC-AD),850(25.2%)patients with ACLF,577(17.1%)patients with chronic hepatitis acute exacer-bation(CHAE),and 269(8.0%)patients with liver cirrhosis active phase(LC-A).The most common cause of chronic liver disease(CLD)was HBV infection(71.4%).The most common precipitants of AoCLD was bacterial infection(22.8%).The 90-d mortality rates of each clinical subtype of AoCLD were 43.4%(232/535)for type-C ACLF,36.0%(36/100)for type-B ACLF,27.0%(58/215)for type-A ACLF,9.0%(151/1679)for LC-AD,3.0%(8/269)for LC-A,and 1.2%(7/577)for CHAE.CONCLUSION HBV infection is the main cause of CLD,and bacterial infection is the main precipitant of AoCLD.The most common clinical type of AoCLD is LC-AD.Early diagnosis and timely intervention are needed to reduce the mortality of patients with LC-AD or ACLF.

基于聚二甲基硅氧烷柔性传感器的研究进展

与传统应变传感器相比,柔性传感器的柔韧性、可穿戴性和实时监测是独特的优点,近年来柔性传感器快速发展并应用于医疗检测、可穿戴设备等多方面,由于聚二甲基硅氧烷(PDMS)的优异理化性质,常作为柔性传感器基底。文中总结了近年来用PDMS作为柔性传感器基底的研究工作,首先对PDMS纳米复合材料的传感机理进行详细的介绍,包括压阻式、电容式与压电式传感机制;然后对以碳纳米管(CNT)、石墨烯与纳米银等为纳米填料的PDMS基柔性传感器进行了详细综述;最后,对PDMS基柔性传感器的研究现状及存在的问题进行了总结并做出展望。

Incidence of infectious complications is associated with a high mortality in patients with hepatitis B virus-related acute-on-chronic liver failure

BACKGROUND In China,hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is the most common liver failure characterized by serious clinical syndromes of liver decompensation with a very high mortality.Bacterial and/or fungal infections are the most common complications that are associated with high short-term mortality.Bacterial translocation from the intestine,impaired hepatic clearance,and immune paralysis of circulating immune cells are thought to contribute to infectious complications in liver failure.The control of bacterial and fungal infections is the key to improving HBV-ACLF outcomes.Active prevention,early diagnosis,and timely treatment of bacterial and fungal infections are essential for treating HBV-ACLF.AIM To investigate the frequency and role of bacterial and fungal infections in patients with HBV-ACLF.METHODS Patients with HBV-ACLF hospitalized at Taihe Hospital,Hubei University of Medicine from January 2014 to December 2017 were retrospectively enrolled.Patient-related information was retrieved from the hospital case database,including general information,blood biochemistry,complications,etc.According to the occurrence of secondary infection or not,the patients were divided into an infection group and a non-infection group.The sites,types,and incidences of bacterial and fungal infections and the influence of infections on the prognosis of HBV-ACLF were statistically analyzed.The risk factors for infections were assessed by unconditional logistic regression.RESULTS There were 174 cases of HBV-ACLF that met the enrollment criteria,of which 114 (65.52%) were diagnosed with infectious complications.Infections occurred in the abdominal cavity (87 cases),respiratory tract (51 cases),urinary tract (18 cases),and biliary tract (10 cases).Patients with infectious complications had a significantly higher 28-d mortality (70.18%,80/114) than those without (40.00%,24/60)(70.18% vs 40.00%,P < 0.05).And patients with infectious complications had a much higher incidence of non-infectious complications (54.39%,62/114)(54.39% vs 15.00%,P < 0.05),leading to an extremely high 28-d mortality of 88.71%(55/62)(P < 0.05).The grade of liver failure,period of hospital stay ≥ 30 d,age ≥ 45 years,and percentage of neutrophils > 70% were identified as risk factors for infectious complications.CONCLUSION The high incidence of infectious complications in patients with HBV-ACLF is associated with severity and deterioration of the disease and may contribute to the extremely high mortality of these patients.

Prevalence and clinical characteristics of autoimmune liver disease in hospitalized patients with cirrhosis and acute decompensation in China

BACKGROUND Autoimmune liver disease(AILD)has been considered a relatively uncommon disease in China,epidemiological data for AILD in patients with cirrhosis and acute decompensation(AD)is sparse.AIM To investigate the prevalence,outcome and risk factors for AILD in cirrhotic patients complicated with AD in China.METHODS We collected data from patients with cirrhosis and AD from two prospective,multicenter cohorts in hepatitis B virus endemic areas.Patients were regularly followed up at the end of 28-d,90-d and 365-d,or until death or liver transplantation(LT).The primary outcome in this study was 90-d LTfree mortality.Acute-on-chronic liver failure(ACLF)was assessed on admission and during 28-d hospitalization,according to the diagnostic criteria of the European Association for the Study of the Liver(EASL).Risk factors for death were analyzed with logistic regression model.RESULTS In patients with cirrhosis and AD,the overall prevalence of AILD was 9.3%(242/2597).Prevalence of ACLF was significantly lower in AILD cases(14%)than those with all etiology groups with cirrhosis and AD(22.8%)(P<0.001).Among 242 enrolled AILD patients,the prevalence rates of primary biliary cirrhosis(PBC),autoimmune hepatitis(AIH)and PBC-AIH overlap syndrome(PBC/AIH)were 50.8%,28.5%and 12.0%,respectively.In ACLF patients,the proportions of PBC,AIH and PBC/AIH were 41.2%,29.4% and 20.6%.28-d and 90-d mortality were 43.8% and 80.0% in AILD-related ACLF.The etiology of AILD had no significant impact on 28-d,90-d or 365-d LTfree mortality in patients with cirrhosis and AD in both univariate and multivariate analysis.Total bilirubin(TB),hepatic encephalopathy(HE)and blood urea nitrogen(BUN)were independent risk factors for 90-d LT-free mortality in multivariate analysis.The development of ACLF during hospitalization only independently correlated to TB and international normalized ratio.CONCLUSION AILD was not rare in hospitalized patients with cirrhosis and AD in China,among which PBC was the most common etiology.90-d LT-free mortality were independently associated with TB,HE and BUN.

Analysis and Design of Distributed Pair Programming System

Pair Programming (PP) that has gained extensive focus within pedagogical and industrial environments is a programming practice in which two programmers use the same computer to work together on analysis, design, and programming of the same segment of code. Distributed Pair Programming (DPP) system is a programming system to aid two programmers, the driver and the navigator, to finish a common task such as analysis, design and programming on the same software from different locations. This paper first reviews the existing DPP tools and discusses the interaction and coordination mechanism in DPP process. By means of activity theory and language-action theory, some basic requirements of the DPP system are presented. Then, a design framework of such system and functions of each sub-system are deeply analyzed. Finally, a system prototype is implemented by plug-in style in Microsoft Visual Studio environment.

基于数据挖掘探讨针灸治疗产后尿失禁选穴规律

目的运用数据挖掘技术探讨针灸治疗产后尿失禁的选穴规律。方法检索中国期刊全文数据库(CNKI)、中国学术期刊数据库(万方数据)、中文科技期刊数据库(重庆维普)、中国生物医学文献数据库(CBM)、中华医学期刊全文数据库、PubMed、Embase、Web of Science建库至2023年2月1日有关针灸治疗产后尿失禁的临床研究文献, 采用Excel 2016软件建立腧穴处方数据库并进行腧穴、归经和特定穴频次统计, 分别采用SPSS Statistics 25.0软件、SPSS Modeler 18.0软件对腧穴进行聚类分析与关联规则分析。结果共纳入文献70篇, 涉及针灸处方70首, 包含腧穴31个, 总频次384次。使用频次排名前5位的腧穴依次为三阴交(46次)、关元(45次)、足三里(43次)、中极(41次)和气海(38次), 常用经脉为任脉、足太阳膀胱经和足太阴脾经, 腧穴多位于下肢部和腹部, 特定穴以交会穴、募穴和五输穴居多。高频腧穴聚类分析得到5个有效聚类群。关联规则分析得到核心腧穴组合为三阴交-足三里-关元-气海-中极。结论产后尿失禁病机以气虚为主, 针灸治疗基于益气健脾、养肺补肾治法, 注重腹部和下肢部腧穴的使用, 并运用上下配穴、前后配穴等配穴方法。

Review of the experimental studies of the cracking behaviors of fracturedrocks under compression

In recent years, many useful experimental results on the cracking behaviors of fractured rocks have been obtainedvia uniaxial, biaxial, triaxial, and Split Hopkinson Pressure Bar (SHPB) tests. In this paper, the influence of theinclination angle of flaws, number of flaws, and patterns of cracks on the mechanical properties during the failureprocess under static loading and dynamic loading conditions is introduced and reviewed. The results show thatthe presence of cracks can decrease the strengths of precracked specimens, and the inclination angles, numbers,and crack patterns of pre-existing flaws can change the mechanical properties and cracking behaviors of precracked specimens. Under static loading, the closer the inclination angle is to 90, the greater the strength, theelastic modulus, and the peak strain of the precracked specimen. However, under dynamic loading, the influenceof the inclination angle varies, and the strength can increase or decrease, possibly in a V-shaped manner. Thischange can be determined by multiple factors, such as the loading path, the materials of the precracked specimen,and the number of pre-existing cracks. Under dynamic loading, the precracked specimen usually exhibits an Xshaped conjugated failure. Additionally, some problems in the study of the cracking behaviors of fractured rocksand related future research are described and presented, and corresponding suggestions and solutions are given.In particular, excavation in deep rock engineering, support of the rock surrounding the tunnel, and mining engineering have important scientific and engineering significance.

New Algorithm Rules Out Acute-on-chronic Liver Failure Development within 28 Days from Acute Decompensation of Cirrhosis

Background and Aims:Approximately 10%of patients with acute decompensated(AD)cirrhosis develop acute-on-chronic liver failure(ACLF)within 28 days.Such cases have high mortality and are difficult to predict.Therefore,we aimed to establish and validate an algorithm to identify these patients on hospitalization.Methods:Hospitalized patients with AD who developed ACLF within 28 days were considered pre-ACLF.Organ dysfunction was defined accord-ing to the chronic liver failure-sequential organ failure as-sessment(CLIF-SOFA)criteria,and proven bacterial infec-tion was taken to indicate immune system dysfunction.A retrospective multicenter cohort and prospective one were used to derive and to validate the potential algorithm,re-spectively.A miss rate of<5%was acceptable for the calcu-lating algorithm to rule out pre-ACLF.Results:In the deri-vation cohort(n=673),46 patients developed ACLF within 28 days.Serum total bilirubin,creatinine,international normalized ratio,and present proven bacterial infection at admission were associated with the development of ACLF.AD patients with≥2 organ dysfunctions had a higher risk for pre-ACLF patients[odds ratio=16.58195%confidence interval:(4.271-64.363),p<0.001].In the derivation co-hort,67.5%of patients(454/673)had≤1 organ dysfunction and two patients(0.4%)were pre-ACLF,with a miss rate of 4.3%(missed/total,2/46).In the validation cohort,65.9%of patients(914/1388)had≤1 organ dysfunction,and four(0.3%)of them were pre-ACLF,with a miss rate of 3.4%(missed/total,4/117).Conclusions:AD patients with≤1 organ dysfunction had a significantly lower risk of developing ACLF within 28 days of admission and could be safely ruled out with a pre-ACLF miss rate of<5%.

Identifying RNA Modifications by Direct RNA Sequencing Reveals Complexity of Epitranscriptomic Dynamics in Rice

Transcriptome analysis based on high-throughput sequencing of a cDNA library has been widely applied to functional genomic studies.However,the cDNA dependence of most RNA sequencing techniques constrains their ability to detect base modifications on RNA,which is an important element for the post-transcriptional regulation of gene expression.To comprehensively profile the N^(6)-methyladenosine(m^(6)A)and N^(5)-methylcytosine(m5 C)modifications on RNA,direct RNA sequencing(DRS)using the latest Oxford Nanopore Technology was applied to analyze the transcriptome of six tissues in rice.Approximately 94 million reads were generated,with an average length ranging from 619 nt to 1013 nt,and a total of 45,707 transcripts across 34,763 genes were detected.Expression profiles of transcripts at the isoform level were quantified among tissues.Transcriptome-wide mapping of m^(6)A and m5 C demonstrated that both modifications exhibited tissue-specific characteristics.The transcripts with m^(6)A modifications tended to be modified by m5 C,and the transcripts with modifications presented higher expression levels along with shorter poly(A)tails than transcripts without modifications,suggesting the complexity of gene expression regulation.Gene Ontology analysis demonstrated that m^(6)A-and m5 C-modified transcripts were involved in central metabolic pathways related to the life cycle,with modifications on the target genes selected in a tissue-specific manner.Furthermore,most modified sites were located within quantitative trait loci that control important agronomic traits,highlighting the value of cloning functional loci.The results provide new insights into the expression regulation complexity and data resource of the transcriptome and epitranscriptome,improving our understanding of the rice genome.

Investigation on the short-term outcome and prognostic impact of predisposition,and precipitants in inpatients with chronic liver disease from Chinese AcuTe on CHronic LIver FailurE(CATCH-LIFE)cohorts

Aim:The study aimed to investigate the short-term outcomes of hospitalized patients with chronic liver disease(CLDs)and assess the prognostic impact of predisposition and precipitants,which currently remains unclear.Methods:The study included 3970 hospitalized patients with CLDs from two prospective longitudinal multicenter studies(NCT02457637 and NCT03641872)conducted in highly endemic hepatitis B virus(HBV)areas.Competing risk analysis was used to evaluate the effect of predispositions,including the etiology and severity of CLDs and precipitants;on sequential 28,90,and 365-day liver transplantation(LT)-free mortality.Results:Among all enrolled patients,76.8%of adverse outcomes(including death and LT)within one year occurred within 90 days.Compared with alcoholic etiology,the association of HBV etiology with poorer outcomes was remarkably on the 28th day(hazard ratio[HR],1.81;95%confidence interval[CI],1.07-3.06;p=0.026);however,and dimin-ished or became insignificant at 90 days and 365 days.Cirrhosis increased the adjusted risk for 365-day(HR,1.50;CI,1.13-1.99;p=0.004)LT-free mortality when compared with noncirrhosis.In patients with cirrhosis,prior decompensation(PD)independently increased the adjusted risk of 365-day LT-free mortality by 1.25-fold(p=0.021);however,it did not increase the risk for 90-day mortality.Neither the category nor the number of precipitants influenced the adjusted risk of 28 or 90-day LT-free mortality.Conclusions:The 90-day outcome should be considered a significant endpoint for evaluating the short-term prognosis of hospitalized patients with CLD.Predisposing factors,other than etiology,mainly affected the delayed(365-day)outcome.Timely effective therapy for CLD etiology,especially antiviral treatments for HBV,and post-discharge long-term surveillance monitoring in cirrhotic patients undergoing PD are suggested to enhance disease management and reduce mortality.

Numerical simulation of macrosegregation in continuously cast gear steel 20CrMnTi with final electromagnetic stirring

A 3D/2D hybrid multi-physical-field mathematical model,which takes into consideration the thermosolutal buoyance,was developed to predict the macrosegregation of gear steel 20CrMnTi continuously cast by a curved billet caster with size of 160 mm×160 mm,and investigated the effect of final electromagnetic stirring(F-EMS)on the fluid flow,heat transfer and solute distribution in the liquid core of continuously cast steel.The results show that the application of F-EMS eliminates the effect of thermosolutal buoyancy on the asymmetric distribution of carbon concentration in the cross section of billet and accelerates the final solidification of resident molten steel in the liquid core of strand,but promotes the negative carbon segregation near the billet center.When the gear steel 20CrMnTi is cast at the temperature of 1803 K and speed of 1.7 m/min,the solidification end advances forward from 9.84 to 9.72 m,and center carbon segregation ratio of billet decreases from 1.24 to 1.17 with the increase in current density of F-EMS from 0 to 350 A.

Numerical Simulation and Experimental Study of F-EMS for Continuously Cast Billet of High Carbon Steel

A final electromagnetic stirring model was developed for billet continuous casting of high carbon steel using the commercial software ANSYS and CFX, and the numerical model was validated by the magnetic flux density measured under a Teslameter CT-3. The magnetic flux density and fluid flow in the liquid pool at the location of final electromagnetic stirring(F-EMS) were calculated by the present numerical model. Meanwhile, the plant trials were carried out to determine the optimum current intensity and frequency of F-EMS for the continuously cast billet of high carbon steel. The numerical results show that, through increasing the current intensity by 100 A, the corresponding increases of magnetic induction intensity, tangential electromagnetic force and flow velocity at the solid/liquid interface in the strand are 0.025 T, 1933 N/m3 and 6.9 cm/s, respectively. Moreover, the industrial trial results showed that for the continuously cast billet of 60 steel, the optimum current intensity and frequency of F-EMS, which is 8.2 m from the meniscus, are respectively 380 A and 6 Hz. With the optimum F-EMS parameters, the significant improvement of center segregation of billet is achieved, and the center carbon segregation index in billet reaches 1.04.

Heat Transfer and Central Segregation of Continuously Cast High Carbon Steel Billet

A numerical model of heat transfer was developed to investigate the heat transfer of continuously cast billet with the aid of surface temperature tests by ThermaCAMTM researcher and nail shooting experiments. The effects of secondary cooling practice and casting speed on the solidification process and central segregation of carbon were investigated as well with the actual central segregation tests. The results show that the surface center and billet center temperatures exhibit a different pattern during solidification, and the solidified shell thickness is presented as an ＂S＂ type. With the increase of secondary cooling intensity and the decrease of casting speed, the end points of the solidus line and the liquidus line move forward, and the central segregation level of carbon decreases. The optimal casting condition is suggested for continuously cast high carbon billet with F-EMS （final electromagnetic stirring）.