Hydrogen embrittlement of Type 4340 steel has been investigated by straining round-notchedspecimens in 105 Pa hydrogen atmosphere at a constent cross-head spead of 1.4x 10-4 mm/s.The circumferentially notched specimen...Hydrogen embrittlement of Type 4340 steel has been investigated by straining round-notchedspecimens in 105 Pa hydrogen atmosphere at a constent cross-head spead of 1.4x 10-4 mm/s.The circumferentially notched specimens exhibited a significant embrittlement when their me-chanical behaviour in hydrogen was compared with that in air. Although the effect of notch depthon fracture strength in air is negligible, an increase in the depth of notch increase susceptibility toembrittlement when testing in gaseous hydrogen. However, analysis of the effects is complicatedby the facts that (i) the specimens show some degree of notch severity even when strained inair and (ii) the behaviour is complicated by the localised plastic deformation that may occur forrelatively shatlow notches. Such effects are eliminated at high stress concentration factors, sothere is a systematic loss in fracture stress in hydrogen as the notch sensitivity increases fromK=2.6 to 5.7 (where a 87% reduction of fracture stress occurs) but a relatively stable value isthen reached even for very severe notching bj fatigue pre-cracking. Whether or not the effectis due to increasing concentration of hydrogen in the triaxial stress region ahead of the notch,there is no doubt that increasing the stress concentration makes hydrogen more effective as anembrittlement agent.展开更多
The coronavirus disease 2019(COVID-19)pandemic has upended healthcare systems worldwide and led to an inevitable decrease in liver transplantation(LT)activity.During the first pandemic wave,administrators and clinicia...The coronavirus disease 2019(COVID-19)pandemic has upended healthcare systems worldwide and led to an inevitable decrease in liver transplantation(LT)activity.During the first pandemic wave,administrators and clinicians were obliged to make the difficult decision of whether to suspend or continue a lifesaving procedure based on the scarce available evidence regarding the risk of transmission and mortality in immunosuppressed patients.Those centers where the activity continued or was heavily restricted were obliged to screen donors and recipients,design COVID-safe clinical pathways,and promote telehealth to prevent nosocomial transmission.Despite the ever-growing literature on COVID-19,the amount of high-quality literature on LT remains limited.This review will provide an updated view of the impact of the pandemic on LT programs worldwide.Donor and recipient screening,strategies for waitlist prioritization,and posttransplant risk of infection and mortality are discussed.Moreover,a particular focus is given to the possibility of donor-to-recipient transmission and immunosuppression management in COVID-positive recipients.展开更多
In order to evaluate the clinical manifestations and outcomes of severe ulcerative colitis(UC),we retrospectively reviewed 41 patients with severe UC from 144 consecutively hospitalized UC cases from 1988 to 2004.Data...In order to evaluate the clinical manifestations and outcomes of severe ulcerative colitis(UC),we retrospectively reviewed 41 patients with severe UC from 144 consecutively hospitalized UC cases from 1988 to 2004.Data recorded included onset,symptoms,signs,laboratory results,endoscopic,radiologic and pathologic findings,the clinical treatment process and follow-up.Of these severe cases,92.7%(38/41)had pancolitis.Clinically,36.9%(15/41)were categorized as first onset type,36.9%(15/41)were chronic persistent and 26.8%(11/41)were chronic recurrent.Steroids played a main role in the remission of severe UC(61.0%).Thirty-one cases(75.6%)were relieved by drug therapy.Seven cases(17.1%)progressed to the need for operation.An early age of onset,pancolitis,low hemoglobin and serum albumin levels,and the need for intravenous steroids tended to be associated with the need for surgery.In conclusion,most of the severe UC patients respond well to drug therapy,but for individuals who are unresponsive to drug therapy,or for those depending on steroids,after a reasonable duration of treatment,the necessity for surgery should be considered.展开更多
In this paper, recursive equations are obtained for compound distribution with the number of claims belonging to (a, b)-family and the severity distribution of the mixed type. Numerical methods to solve these equation...In this paper, recursive equations are obtained for compound distribution with the number of claims belonging to (a, b)-family and the severity distribution of the mixed type. Numerical methods to solve these equations are presented, and some numerical results are given.展开更多
Background Gut microbiota alterations have been implicated in the pathogenesis of coronavirus disease 2019(COVID-19).This study aimed to explore gut microbiota changes in a prospective cohort of COVID-19 children and ...Background Gut microbiota alterations have been implicated in the pathogenesis of coronavirus disease 2019(COVID-19).This study aimed to explore gut microbiota changes in a prospective cohort of COVID-19 children and their asymptomatic caregivers infected with the severe acute respiratory syndrome coronavirus type 2(SARS-CoV-2)Omicron variant.Methods A total of 186 participants,including 59 COVID-19 children,50 asymptomatic adult caregivers,52 healthy children(HC),and 25 healthy adults(HA),were recruited between 15 April and 31 May 2022.The gut microbiota composition was determined by 16S rRNA gene sequencing in fecal samples collected from the participants.Gut microbiota functional profling was performed by using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States(PICRUSt)software.Results The gut microbiota analysis of beta diversity revealed that the fecal microbial community of COVID-19 children remained far distantly related to HC.The relative abundances of the phyla Actinobacteria and Firmicutes were decreased,whereas Bacteroidetes,Proteobacteria,and Verrucomicrobiota were increased in COVID-19 children.Feces from COVID-19 children exhibited notably lower abundances of the genera Blautia,Bifdobacterium,Fusicatenibacter,Streptococcus,and Romboutsia and higher abundances of the genera Prevotella,Lachnoclostridium,Escherichia-Shigella,and Bacteroides than those from HC.The enterotype distributions of COVID-19 children were characterized by a high prevalence of enterotype Bacteroides.Similar changes in gut microbiota compositions were observed in asymptomatic caregivers.Furthermore,the microbial metabolic activities of KEGG(Kyoto Encyclopedia of Genes and Genomes)and COG(cluster of orthologous groups of proteins)pathways were perturbed in feces from subjects infected with the SARS-CoV-2 Omicron variant.Conclusion Our data reveal altered gut microbiota compositions in both COVID-19 children and their asymptomatic caregivers infected with the SARS-CoV-2 Omicron variant,which further implicates the critical role of gut microbiota in COVID-19 pathogenesis.展开更多
Coronavirus disease 2019(COVID-19)is a highly contagious disease and a serious threat to human health.COVID-19 can cause multiple organ dysfunction,such as respiratory and circulatory failure,liver and kidney injury,d...Coronavirus disease 2019(COVID-19)is a highly contagious disease and a serious threat to human health.COVID-19 can cause multiple organ dysfunction,such as respiratory and circulatory failure,liver and kidney injury,disseminated intravascular coagulation,and thromboembolism,and even death.The World Health Organization reports that the mortality rate of severe-type COVID-19 is over 50%.Currently,the number of severe cases worldwide has increased rapidly,but the experience in the treatment of infected patients is still limited.Given the lack of specific antiviral drugs,multi-organ function support treatment is important for patients with COVID-19.To improve the cure rate and reduce the mortality of patients with severe-and critical-type COVID-19,this paper summarizes the experience of organ function support in patients with severe-and criticaltype COVID-19 in Optical Valley Branch of Tongji Hospital,Wuhan,China.This paper systematically summarizes the procedures of functional support therapies for multiple organs and systems,including respiratory,circulatory,renal,hepatic,and hematological systems,among patients with severe-and critical-type COVID-19.This paper provides a clinical reference and a new strategy for the optimal treatment of COVID-19 worldwide.展开更多
文摘Hydrogen embrittlement of Type 4340 steel has been investigated by straining round-notchedspecimens in 105 Pa hydrogen atmosphere at a constent cross-head spead of 1.4x 10-4 mm/s.The circumferentially notched specimens exhibited a significant embrittlement when their me-chanical behaviour in hydrogen was compared with that in air. Although the effect of notch depthon fracture strength in air is negligible, an increase in the depth of notch increase susceptibility toembrittlement when testing in gaseous hydrogen. However, analysis of the effects is complicatedby the facts that (i) the specimens show some degree of notch severity even when strained inair and (ii) the behaviour is complicated by the localised plastic deformation that may occur forrelatively shatlow notches. Such effects are eliminated at high stress concentration factors, sothere is a systematic loss in fracture stress in hydrogen as the notch sensitivity increases fromK=2.6 to 5.7 (where a 87% reduction of fracture stress occurs) but a relatively stable value isthen reached even for very severe notching bj fatigue pre-cracking. Whether or not the effectis due to increasing concentration of hydrogen in the triaxial stress region ahead of the notch,there is no doubt that increasing the stress concentration makes hydrogen more effective as anembrittlement agent.
文摘The coronavirus disease 2019(COVID-19)pandemic has upended healthcare systems worldwide and led to an inevitable decrease in liver transplantation(LT)activity.During the first pandemic wave,administrators and clinicians were obliged to make the difficult decision of whether to suspend or continue a lifesaving procedure based on the scarce available evidence regarding the risk of transmission and mortality in immunosuppressed patients.Those centers where the activity continued or was heavily restricted were obliged to screen donors and recipients,design COVID-safe clinical pathways,and promote telehealth to prevent nosocomial transmission.Despite the ever-growing literature on COVID-19,the amount of high-quality literature on LT remains limited.This review will provide an updated view of the impact of the pandemic on LT programs worldwide.Donor and recipient screening,strategies for waitlist prioritization,and posttransplant risk of infection and mortality are discussed.Moreover,a particular focus is given to the possibility of donor-to-recipient transmission and immunosuppression management in COVID-positive recipients.
文摘In order to evaluate the clinical manifestations and outcomes of severe ulcerative colitis(UC),we retrospectively reviewed 41 patients with severe UC from 144 consecutively hospitalized UC cases from 1988 to 2004.Data recorded included onset,symptoms,signs,laboratory results,endoscopic,radiologic and pathologic findings,the clinical treatment process and follow-up.Of these severe cases,92.7%(38/41)had pancolitis.Clinically,36.9%(15/41)were categorized as first onset type,36.9%(15/41)were chronic persistent and 26.8%(11/41)were chronic recurrent.Steroids played a main role in the remission of severe UC(61.0%).Thirty-one cases(75.6%)were relieved by drug therapy.Seven cases(17.1%)progressed to the need for operation.An early age of onset,pancolitis,low hemoglobin and serum albumin levels,and the need for intravenous steroids tended to be associated with the need for surgery.In conclusion,most of the severe UC patients respond well to drug therapy,but for individuals who are unresponsive to drug therapy,or for those depending on steroids,after a reasonable duration of treatment,the necessity for surgery should be considered.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.19831020&10071003).
文摘In this paper, recursive equations are obtained for compound distribution with the number of claims belonging to (a, b)-family and the severity distribution of the mixed type. Numerical methods to solve these equations are presented, and some numerical results are given.
基金supported by the grants from the National Natural Science Foundation of China(No.81870373)the Natural Science Foundation of Shanghai(No.22ZR1451800).
文摘Background Gut microbiota alterations have been implicated in the pathogenesis of coronavirus disease 2019(COVID-19).This study aimed to explore gut microbiota changes in a prospective cohort of COVID-19 children and their asymptomatic caregivers infected with the severe acute respiratory syndrome coronavirus type 2(SARS-CoV-2)Omicron variant.Methods A total of 186 participants,including 59 COVID-19 children,50 asymptomatic adult caregivers,52 healthy children(HC),and 25 healthy adults(HA),were recruited between 15 April and 31 May 2022.The gut microbiota composition was determined by 16S rRNA gene sequencing in fecal samples collected from the participants.Gut microbiota functional profling was performed by using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States(PICRUSt)software.Results The gut microbiota analysis of beta diversity revealed that the fecal microbial community of COVID-19 children remained far distantly related to HC.The relative abundances of the phyla Actinobacteria and Firmicutes were decreased,whereas Bacteroidetes,Proteobacteria,and Verrucomicrobiota were increased in COVID-19 children.Feces from COVID-19 children exhibited notably lower abundances of the genera Blautia,Bifdobacterium,Fusicatenibacter,Streptococcus,and Romboutsia and higher abundances of the genera Prevotella,Lachnoclostridium,Escherichia-Shigella,and Bacteroides than those from HC.The enterotype distributions of COVID-19 children were characterized by a high prevalence of enterotype Bacteroides.Similar changes in gut microbiota compositions were observed in asymptomatic caregivers.Furthermore,the microbial metabolic activities of KEGG(Kyoto Encyclopedia of Genes and Genomes)and COG(cluster of orthologous groups of proteins)pathways were perturbed in feces from subjects infected with the SARS-CoV-2 Omicron variant.Conclusion Our data reveal altered gut microbiota compositions in both COVID-19 children and their asymptomatic caregivers infected with the SARS-CoV-2 Omicron variant,which further implicates the critical role of gut microbiota in COVID-19 pathogenesis.
文摘Coronavirus disease 2019(COVID-19)is a highly contagious disease and a serious threat to human health.COVID-19 can cause multiple organ dysfunction,such as respiratory and circulatory failure,liver and kidney injury,disseminated intravascular coagulation,and thromboembolism,and even death.The World Health Organization reports that the mortality rate of severe-type COVID-19 is over 50%.Currently,the number of severe cases worldwide has increased rapidly,but the experience in the treatment of infected patients is still limited.Given the lack of specific antiviral drugs,multi-organ function support treatment is important for patients with COVID-19.To improve the cure rate and reduce the mortality of patients with severe-and critical-type COVID-19,this paper summarizes the experience of organ function support in patients with severe-and criticaltype COVID-19 in Optical Valley Branch of Tongji Hospital,Wuhan,China.This paper systematically summarizes the procedures of functional support therapies for multiple organs and systems,including respiratory,circulatory,renal,hepatic,and hematological systems,among patients with severe-and critical-type COVID-19.This paper provides a clinical reference and a new strategy for the optimal treatment of COVID-19 worldwide.
