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Experimental study on the influences of cutter geometry and material on scraper wear during shield TBM tunnelling in abrasive sandy ground

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 410-425页

作者： Shaohui tang xiaoping Zhang Quansheng Liu Qi Zhang Xinfang Li Haojie Wang Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China

When shield TBM tunnelling in abrasive sandy ground,the rational design of cutter parameters is critical to reduce tool wear and improve tunnelling efficiency.However,the influence mechanism of cutter parameters on scraper wear remains unclear due to the lack of a reliable test method.Geometry and material optimisation are often based on subjective experience,which is unfavourable for improving scraper geological adaptability.In the present study,the newly developed WHU-SAT soil abrasion test was used to evaluate the variation in scraper wear with cutter geometry,material and hardness.The influence mechanism of cutter parameters on scraper wear has been revealed according to the scratch characteristics of the scraper surface.Cutter geometry and material parameters have been optimised to reduce scraper wear.The results indicate that the variation in scraper wear with cutter geometry is related to the cutting resistance,frictional resistance and stress distribution.An appropriate increase in the front angle(or back angle)reduces the cutting resistance(or frictional resistance),while an excessive increase in the front angle(or back angle)reduces the edge angle and causes stress concentration.The optimal front angle,back angle and edge angle for quartz sand samples areα=25°,β=10°andγ=55°,respectively.The wear resistance of the modelled scrapers made of different metal materials is related to the chemical elements and microstructure.The wear resistances of the modelled scrapers made of 45#,06Cr19Ni10,42CrMo4 and 40CrNiMoA are 0.569,0.661,0.691 and 0.728 times those made of WC-Co,respectively.When the alloy hardness is less than 47 HRC(or greater than 58 HRC),scraper wear decreases slowly with increasing alloy hardness as the scratch depth of the particle asperity on the metal surface stabilizes at a high(or low)level.However,when the alloy hardness is between 47 HRC and 58 HRC,scraper wear decreases rapidly with increasing alloy hardness as the scratch depth transitions from high to low levels.The sensitive hardness i

关键词： Shield TBM Scraper wear Cutter shape Metal material Alloy hardness

Advances in diagnosis andtreatment of talaromycosis in patients WithAIDS

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Chinese Medical Journal 2022年第22期135卷 2687-2689页

作者： Pengle Guo Linghua Li xiaoping tang Guangzhou Eighth People's Hospital Guangzhou Medical UniversityGuangzhouGuangdong 510060China

Talaromycosis(formerly named penicilliosis)is an important invasive mycosis caused by Talaromyces marneffei(formerly Penicillium marneffei,T.marneffei).[1]The World Health Organization and Food and Drug Administration have recently paid increasing attention to the disease as a neglected tropical disease due to the growing burden of T.marneffei infection globally.[1,2]Talaromycosis is a common opportunistic disease and a leading cause of death in patients with acquired immune deficiency syndrome(AIDS)in endemic regions;moreover,it is increasingly being reported in human immunodeficiency virus(HIV)-negative individuals and outside of epidemic areas.[3,4]The mortality of talaromycosis is up to 30%in both HIV-positive and HIV-negative individuals,which is associated with late diagnosis and untimely or ineffective antifungal therapy.[5]Therefore,early diagnosis and effective antifungal treatment are critical to reduce the mortality.

关键词： diagnosis treatment AIDS

The compartmentalized upper respiratory mucosa needs time to rally a sufficient immune force for SARS-CoV-2 clearance

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Cellular & Molecular Immunology 2022年第12期19卷 1425-1428页

作者： Xiaowen Zheng xiaoping tang Feng Li Guangzhou Eighth People’s Hospital Guangzhou Medical UniversityGuangzhou510440China Guangzhou Laboratory Bio-IslandGuangzhou510320China

SARS-CoV-2 viral reoccurrence,which is defined as reliable detection of mature virus or viral products in discharged or recovered individuals with at least two consecutive negative detections of viral genomic ribonucleic acid(RNA)by standard reverse transcription polymerase chain reaction(RT‒PCR),raises public concerns about transmission risk and warrants exploration of the underlying mechanism.

关键词： mechanism. mucosa respiratory

Nutrient enrichment driven by canopy rainfall redistribution:Mechanism,quantification,and pattern

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Science China Earth Sciences 2024年第5期67卷 1529-1544页

作者： Chuan YUAN xiaoping YUE Yafeng ZHANG Yu ZHANG Yanting HU Qiang tang Li GUO Shuai WANG Xingwu DUAN Wenhua XIANG Xiaohua WEI Xiaoyan LI College of Forestry and Biotechnology Zhejiang A&F UniversityHangzhou 311300China Chongqing Jinfo Mountain Karst Ecosystem National Observation and Research Station School of Geographical SciencesSouthwest UniversityChongqing 400715China Shapotou Desert Research and Experiment Station Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China School of Geographical Sciences Hebei Normal UniversityShijiazhuang 050024China Faculty of Life Science and Technology Central South University of Forestry and TechnologyChangsha 410004China State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu 610065China State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Yunnan Key Laboratory of Soil Erosion Prevention and Green Development Institute of International Rivers and Eco-securityYunnan UniversityKunming 650091China Department of Earth Environmental and Geographic SciencesUniversity of British Columbia(Okanagan)KelownaBritish Columbia V1V 1V7Canada

Vegetation canopies intercept and redistribute rainfall into throughfall and stemflow,which transfer substantial amounts of elements into the soil,influencing soil microbial community,plant survival,and plant community succession.Despite advancements in ecohydrological research,the implication of nutrient enrichment resulting from this redistribution of rainfall by canopies remains largely unexplored.To address this gap,we conducted a systematic review of 1020 papers published between 2000 and 2022,gathering data on nutrient concentration and enrichment for critical ions(including K^(+),Na^(+),Ca^(2+),Mg^(2+),NH_(4)^(+),Cl^(-),NO_(3)^(-)and SO_(4)^(2-))from the Web of Science and Chinese Knowledge Infrastructure databases.We aimed to synthesize the mechanisms,quantify the enrichments,and identify global patterns of nutrient enrichment in stemflow and throughfall across climate zones,and vegetation types and ecosystems.The results of this study indicate that stemflow exhibits,on average,2.1times greater ion concentration(6.13 mg L^(-1))compared to throughfall.In particular,among the investigated ions,SO_(4)^(2-)(12.45and 6.32 mg L^(-1))for stemflow and throughfall,respectively,and Cl^(-)(9.21 and 4.81 mg L^(-1))exhibit the highest concentrations in both rainfall redistribution components,while K^(+)(13.7 and 5.8)and Mg^(2+)(5.6 and 2.8)have the highest enrichment factors.Across climate zones,throughfall and stemflow show the lowest ion concentrations but the highest enrichment factors in extremely humid regions.Along the temperature gradient,ion concentrations are the highest in cold climates with no clear patterns observed for enrichment factors with increasing temperature.In addition,shrubs,conifers,mixed forests,and artificial ecosystems demonstrate enrichment factors 1.1 to 3.0 times greater than those of trees,broad-leaved plants,pure forests,and natural ecosystems.These findings emphasize the need for increased attentions to artificial ecosystems,such as urban and agricultural ecosystems,which often received

关键词： Ecohydrology Rainfall redistribution Nutrients transport Enrichment characteristics Climate zones

A three-dose inactivated SARS-CoV-2 vaccine is sufficient to elicit humoral immune responses in people living with HIV-1

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Chinese Medical Journal 2023年第18期136卷 2243-2245页

作者： Haisheng Yu Pengle Guo Yingyin Yang Jun Dai xiaoping tang Linghua Li Guangzhou Eighth People’s Hospital Guangzhou Medical UniversityGuangzhouGuangdong 510440China

To the Editor:Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is the virus that caused the 2019 coronavirus disease(COVID-19)pandemic.Over two years after the initial outbreak,several more infectious variations of the virus continue to pose a grave threat to global public health.[1]Intense,worldwide efforts for vaccine development have led to several candidate vaccines utilizing a variety of platforms.

关键词： vaccine acute respiratory

Laser speckle contrast imaging to predict the effect of temporary spinal cord stimulation in postherpetic neuralgia patients: A prospective observational study

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Journal of Innovative Optical Health Sciences 2024年第1期17卷 69-75页

作者： Xiang Huang Dacheng tang Pan Chen Lumiao Chen Xiaohong Li xiaoping Wang Department of Pain Management The First A±liated Hospital Jinan University Guang ZhouGuangdong 510630P.R.China Department of Pain Management The First People's Hospital of Foshan Foshan City Guangdong 528000P.R.China

Temporary spinal cord stimulation(tSCS)can effectively reduce the pain and severity of postherpetic neuralgia(PHN).However,there are no effective and objective methods for predicting the effects of tSCS on PHN.Laser speckle contrast imaging(LSCI)is frequently used in neurology to evaluate the effectiveness of treatment.To assess the accuracy of LSCI in predicting the impact of tSCS on PHN,14 adult patients receiving tSCS treatments for spinal nerve-innervated(C6-T2)PHN participated in this observational study.Visual analog scale(VAS)assessments and LSCI bloodflow images of the-ngers were recorded after the tSCS procedure.The results showed that the VAS scores of all patients decreased signi-cantly.Moreover,the bloodflow index(BFI)values were signi-cantly higher than they were before the procedure.Increased bloodflow and pain alleviation were positively correlated.The-ndings indicated that spinal nerve PHN(C6-T2)was signi-cantly reduced by tSCS.Pain alleviation by tSCS was positively correlated with increased bloodflow in the hand.The effect of tSCS on PHN may thus be predicted using an independent and consistent indicator such as LSCI.

关键词： Laser speckle contrast imaging temporary spinal cord stimulation postherpetic neuralgia

Incidence and factors associated with hepatitis B surface antigen seroclearance in patients co-infected with HBV/HIV during antiretroviral therapy in Guangdong,China

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Chinese Medical Journal 2023年第22期136卷 2686-2693页

作者： Yaozu He Weiyin Lin Hong Li Fei Gu Huolin Zhong Yun Lan Yonghong Li Pengle Guo Fengyu Hu Weiping Cai xiaoping tang Linghua Li Infectious Disease Center Guangzhou Eighth People’s HospitalGuangzhou Medical UniversityGuangzhouGuangdong 510060China

Background:Hepatitis B surface antigen(HBsAg)clearance is vital for a functional cure of hepatitis B virus(HBV)infection.However,the incidence and predictors of HBsAg seroclearance in patients co-infected with HBV and human immunodeficiency virus(HIV)remain largely unknown in Guangdong,China.Methods:Between 2009 and 2019,patients co-infected with HBV/HIV undergoing antiretroviral therapy(ART)in Guangzhou Eighth People’s Hospital affiliated to Guangzhou Medical University were retrospectively reviewed with the endpoint on December 31,2020.The incidence and risk factors for HBsAg seroclearance were evaluated using Kaplan-Meier and multivariate Cox regression analyses.Results:A total of 1550 HBV/HIV co-infected patients were included in the study,with the median age of 42 years and 86.0%(1333/1550)males.Further,98.3%(1524/1550)received ART containing tenofovir disoproxil fumarate(TDF)plus lamivudine(3TC).HBV DNA was examined in 1283 cases at the last follow-up.Over the median 4.7 years of follow-up,8.1%(126/1550)patients achieved HBsAg seroclearance,among whom 50.8%(64/126)obtained hepatitis B surface antibody,28.1%(137/488)acquired hepatitis B e antigen seroconversion,and 95.9%(1231/1283)undetectable HBV DNA.Compared with patients who maintained HBsAg positive,cases achieving HBsAg seroclearance showed no differences in age,gender,CD4+T cell count,alanine aminotransferase(ALT)level,or fibrosis status;however,they presented lower HBV DNA levels,lower HBsAg levels,and higher rates of HBV genotype B at the baseline.Multivariate analysis showed that baseline HBsAg2×upper limit of normal during the first six months after receiving ART(aHR,2.96,95%CI:1.53-5.77),and HBV genotype B(aHR,3.73,95%CI:1.46-9.59)were independent predictors for HBsAg seroclearance(all P<0.01).Conclusions:Long-term TDF-containing ART has high anti-HBV efficacy including relatively high overall HBsAg seroclearance in HBV/HIV co-infected pa

关键词： HBV/HIV co-infection HBsAg seroclearance Predictor ALT elevation HBV genotype Hepatitis B surface antigens Tenofovir disoproxil fumarate

Characteristics of SARS-CoV-2 Delta variant-infected individuals with intermittently positive retest viral RNA after discharge

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National Science Review 2022年第10期9卷 63-66页

作者： Lu Li Jingyan tang Zhiwei Xie Qingxin Gan Guofang tang Zhongwei Hu Huimin Zeng Jingrong Shi Jiaojiao Li Yan Li Changwen Ke Min Kang Dan Liang Huan Lu Yuwei Tong Xilong Deng Jinxin Liu Hongzhou Lu Fuxiang Wang Fengyu Hu Feng Li Nanshan Zhong xiaoping tang Guangzhou Eighth People's Hospital Guangzhou Medical University Guangdong Provincial Center for Disease Control and Prevention The Third People's Hospital of Shenzhen Guangzhou Laboratory National Clinical Research Center for Respiratory Diseases of First Affiliated Hospital Guangzhou Medical University

SARS-CoV-2-infected patients will be discharged when viral ribonucleic acid(RNA) is consecutively negative at least twice over a 24-h interval.However,we have demonstrated that positive retest viral RNA,a particular clinical phenomenon initially observed in discharged SARS-CoV-2-infected patients in early 2020 [1,2],is the occasional reoccurrence of Polymerase Chain Reaction (PCR)-detectable viral RNA but not reinfection [3].Unfortunately,workable strategies to effectively discriminate against individuals likely to have positive retest viral RNA are still absent.Thus,for safety concerns,a mandatory minimum of 14-day quarantine in hospitals or hotels had been strictly applied for discharged patients.Given that the Delta Variant of Concern (VOC),the dominant SARS-CoV-2 strain in 2021,

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Persistently low CD4 cell counts are associated with hepatic events in HCV/HIV coinfected patients: data from the national free antiretroviral treatment program of China

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Chinese Medical Journal 2022年第22期135卷 2699-2705页

作者： Weiyin Lin Huolin Zhong Chunyan Wen Yaozu He Xiaowen Zheng Hong Li Xiejie Chen Haolan He Jinfeng Chen Lijuan Chen Cong Liu xiaoping tang Weiping Cai Linghua Li Guangzhou Eighth People's Hospital Guangzhou Medical UniversityGuangzhouGuangdong 510060China

Background: Chronic liver disease has emerged as a leading cause of non-acquired immune deficiency syndrome (AIDS)-related mortality in hepatitis C virus (HCV)/human immunodeficiency virus (HIV)-coinfected patients. The relationship between CD4 cell count and HIV-related opportunistic infections and tumors has been well characterized;however, it is unclear whether CD4 cell count is associated with HCV-related hepatic events.Methods: This observational cohort study enrolled HCV/HIV-coinfected patients from the National Free Antiretroviral Treatment Program of China from 2004 to 2019 in Guangzhou. The primary outcome was a composite of hepatic events, including cirrhosis complications, hepatocellular carcinoma (HCC), and liver-related mortality. Kaplan-Meier survival and multivariate logistic regression analyses were performed.Results: Among the 793 patients, 43 developed hepatic events during a median follow-up of 6.7 years, including 35 cirrhosis complications, 13 HCC cases, and 14 cases of liver-related mortality. The 5-year and 10-year cumulative incidences of hepatic events were 4.2% and 9.3%, respectively. Patients who developed hepatic events had a less satisfactory increase in CD4 cell count, lower peak CD4 (354.5 cells/μLvs. 560.0 cells/μL,P 500 cells/μL (30.2%vs. 60.7%,P 500 cells/μL. Peak CD4 was negatively associated with the risk of hepatic events in a dose-response manner (P-value for trend = 0.004).Conclusion: Persistently low CD4 cell counts after ART are independently associated with a high risk of hepatic events

关键词： CD4 cell count Co-infection Hepatic events Hepatitis C virus Human immunodeficiency virus