Pt-based relaxor ferroelectric single crystals such as Pb(Mg1/3Nb2/3)O3-PbTiO3(PMN-PT)and Pb(Zn1/3Nb2/3)O3-Pb TiO3(PZN-PT),were reported as a novel piezoelectric materials with high properties at 1990's,which
Introduction:In November 2021,the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)Omicron variant was identified as the variant of concern and has since spread globally,replacing other cocirculating variant...Introduction:In November 2021,the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)Omicron variant was identified as the variant of concern and has since spread globally,replacing other cocirculating variants.To better understand the dynamic changes in viral load over time and the natural history of the virus infection,we analyzed the expression of the open reading frames 1ab(ORF1ab)and nucleocapsid(N)genes in patients infected with Omicron.Methods:We included patients initially admitted to the hospital for SARS-CoV-2 infection between November 5 and December 25,2022.We collected daily oropharyngeal swabs for quantitative reverse transcriptase-polymerase chain reaction tests using commercial kits.We depicted the cycle threshold(Ct)values for amplification of ORF1ab and N genes from individual patients in age-specific groups in a time series.Results:A total of 480 inpatients were included in the study,with a median age of 59 years(interquartile range,42 to 78;range,16 to 106).In the<45-year-old age group,the Ct values for ORF1ab and N gene amplification remained below 35 for 9.0 and 11.5 days,respectively.In the≥80-year-old age group,the Ct values for ORF1ab and N genes stayed below 35 for 11.5 and 15.0 days,respectively,which was the longest among all age groups.The Ct values for N gene amplification took longer to rise above 35 than those for ORF1ab gene amplification.Conclusion:The time to test negative varied among different age groups,with viral nucleic acid shedding taking longer in older age groups compared to younger age groups.As a result,the time to resolution of Omicron infection increased with increasing age.展开更多
Bulk crystals of high Curie temperature(T_(C))24Pb(In_(1/2(Nb_(1/2))O_(3)-43Pb(Mg_(1/3)Nb_(2/3))O_(3)-33PbTiO_(3)(24PIN-43PMN-33PT)with 55 mm in diameter and 130mm in length were reproducibly grown by the bottom-seede...Bulk crystals of high Curie temperature(T_(C))24Pb(In_(1/2(Nb_(1/2))O_(3)-43Pb(Mg_(1/3)Nb_(2/3))O_(3)-33PbTiO_(3)(24PIN-43PMN-33PT)with 55 mm in diameter and 130mm in length were reproducibly grown by the bottom-seeded Bridgman method.The X-ray diffraction(XRD)spectrum indicated that the as-grown crystal was a single phase with rthombohedral structure at room temperature,the domain morphology and the phase transition sequence of R→T→C were observed,the full width at half maximum(FWHM)of X-ray rocking curve of(002)face was about 0.77°,and the defect density was inferred to 2.56×10^(10)cm^(-2).The measured density of the as-grown crystals was very close to the theoretical one.Variation of the transition temperature of the as-grown crystals along the growth direction revealed that T_(C) increased linearly along the growth direction and rthombohedral to tetrahedral phase transition temperature(T_(RT))gradually decreased in the middle part of the ingot.展开更多
Introduction:Repeat positive severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)following COVID-19 initial viral clearance(repositivity)poses a public health management challenge.The objective was to determine...Introduction:Repeat positive severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)following COVID-19 initial viral clearance(repositivity)poses a public health management challenge.The objective was to determine factors associated with neutralizing antibody(Nab)level and re-positivity among patients infected with a single strain SARS-CoV-2.Methods:During a single strain SARS-CoV-2 cluster in Beijing,China,longitudinal individual clinical,virological,and immunological data were collected from 368 infections from June 13 to September 22,2020.Factors associated with Nab level and re-positivity were analyzed using generalized estimating equations.Results:A total of 353(96%)SARS-CoV-2 infections had demographic,clinical,and laboratory data available.Among the 353 infections,55(15.5%)were re-positive,and blood draws were taken from 346 individuals(98.0%)during hospitalization and/or during the follow-up period.Symptoms were milder for the second-time admission for the re-positives,although 36.4%of re-positives presented with radiographic appearance of pneumonia manifestation.Compared to non-re-positive patients,NAb titers were lower among re-positives;NAb was positively associated with clinical severity.Samples from the lower respiratory tract manifested higher viral load than that from the upper respiratory tract.Multivariable analysis showed re-positivity was positively associated with being female[odd ratio(OR)=1.7,95%confidence interval(CI)1.1–2.8]and being aged<18 years(OR=5.2,95%CI 1.5–18.1);having initially asymptomatic infection(OR=13.7,95%CI 1.6–116.3);and negatively associated with a higher NAb level(OR=0.9,95%CI 0.5–1.7).Conclusions:NAb may be important for sustained viral clearance.Lower respiratory tract infection was associated with higher viral load among all infections when compared to upper respiratory tract infection.Continuous lower respiratory and intermittent upper respiratory viral shedding among COVID-19 infections may occur.展开更多
SARS-CoV-2 has caused over 100 million deaths and continues to spread rapidly around the world.Asymptomatic transmission of SARS-CoV-2 is the Achilles’heel of COVID-19 public health control measures.Phylogenomic data...SARS-CoV-2 has caused over 100 million deaths and continues to spread rapidly around the world.Asymptomatic transmission of SARS-CoV-2 is the Achilles’heel of COVID-19 public health control measures.Phylogenomic data on SARS-CoV-2 could provide more direct information about asymptomatic transmission.In this study,using a novel MINERVA sequencing technology,we traced asymptomatic transmission of COVID-19 patients in Beijing,China.One hundred and seventy-eight close contacts were quarantined,and 14 COVID-19 patients were laboratory confirmed by RT-PCR.We provide direct phylogenomic evidence of asymptomatic transmission by constructing the median joining network in the cluster.These data could help us to determine whether the current symptom-based screening should cover asymptomatic persons.展开更多
Dear Editor,The coronavirus disease 2019(COVID-19)pandemic is generating a demand for simultaneous vaccine development,which is expected to prevent future outbreaks by eliciting sufficient and protective immunity.
The ongoing coronavirus disease 2019(COVID-19)pandemic caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection has led to over 240 million confirmed infections and severe economic burdens worldw...The ongoing coronavirus disease 2019(COVID-19)pandemic caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection has led to over 240 million confirmed infections and severe economic burdens worldwide.Multiple emerging SARS-CoV-2 variants of concern(VOCs)and variants of interest(VOIs)have recently beenidentifiedand are nowspreading internationally,including B.1.1.7(Alpha),B.1.351(Beta),P.1(Gamma),B.1.617(Delta and Kappa),C.37(Lambda),and B.1.621(Mu),all of which appear to bemore easily transmitted(WHO,COVID-19Weekly EpidemiologicalUpdate).Beta andGamma VOCs can seriously impair the protective efficacy of existing vaccines,potentially precluding the possibility of attaining"herd immunity."展开更多
Few reports are available about prolonged shedding of coronavirus disease(COVID-19)virus,also known as severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),by immunocompetent patients.We report a case of an inf...Few reports are available about prolonged shedding of coronavirus disease(COVID-19)virus,also known as severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),by immunocompetent patients.We report a case of an infected,immunocompetent person with 169 days of COVID-19 virus shedding during which time he had two brief periods when he tested negative for COVID-19 followed by again testing positive.We describe relevant clinical,immunological,and genomic features.We found that continuous and prolonged viral replication and infectivity existed in an immunocompetent COVID-19 patient,despite having high neutralizing antibody titers.展开更多
文摘Pt-based relaxor ferroelectric single crystals such as Pb(Mg1/3Nb2/3)O3-PbTiO3(PMN-PT)and Pb(Zn1/3Nb2/3)O3-Pb TiO3(PZN-PT),were reported as a novel piezoelectric materials with high properties at 1990's,which
基金Funded by National Key R&D Program of China(2021ZD0114103)the Capital's Funds for Health Improvement and Research(2022-4G-30117)the Beijing Science and Technology Planning Project of Beijing Science and Technology Commission(Z211100002521015 and Z211100002521019).
文摘Introduction:In November 2021,the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)Omicron variant was identified as the variant of concern and has since spread globally,replacing other cocirculating variants.To better understand the dynamic changes in viral load over time and the natural history of the virus infection,we analyzed the expression of the open reading frames 1ab(ORF1ab)and nucleocapsid(N)genes in patients infected with Omicron.Methods:We included patients initially admitted to the hospital for SARS-CoV-2 infection between November 5 and December 25,2022.We collected daily oropharyngeal swabs for quantitative reverse transcriptase-polymerase chain reaction tests using commercial kits.We depicted the cycle threshold(Ct)values for amplification of ORF1ab and N genes from individual patients in age-specific groups in a time series.Results:A total of 480 inpatients were included in the study,with a median age of 59 years(interquartile range,42 to 78;range,16 to 106).In the<45-year-old age group,the Ct values for ORF1ab and N gene amplification remained below 35 for 9.0 and 11.5 days,respectively.In the≥80-year-old age group,the Ct values for ORF1ab and N genes stayed below 35 for 11.5 and 15.0 days,respectively,which was the longest among all age groups.The Ct values for N gene amplification took longer to rise above 35 than those for ORF1ab gene amplification.Conclusion:The time to test negative varied among different age groups,with viral nucleic acid shedding taking longer in older age groups compared to younger age groups.As a result,the time to resolution of Omicron infection increased with increasing age.
基金financially supported by the National Nature Science Foundation of China(Grant No.51002116)the Fundamental Research Funds for Central Universities+1 种基金the National Basic Research Program of China(973 Program)(Grant No.2009CB623306)the National Nature Science foundation of China(Grant No.10976022).
文摘Bulk crystals of high Curie temperature(T_(C))24Pb(In_(1/2(Nb_(1/2))O_(3)-43Pb(Mg_(1/3)Nb_(2/3))O_(3)-33PbTiO_(3)(24PIN-43PMN-33PT)with 55 mm in diameter and 130mm in length were reproducibly grown by the bottom-seeded Bridgman method.The X-ray diffraction(XRD)spectrum indicated that the as-grown crystal was a single phase with rthombohedral structure at room temperature,the domain morphology and the phase transition sequence of R→T→C were observed,the full width at half maximum(FWHM)of X-ray rocking curve of(002)face was about 0.77°,and the defect density was inferred to 2.56×10^(10)cm^(-2).The measured density of the as-grown crystals was very close to the theoretical one.Variation of the transition temperature of the as-grown crystals along the growth direction revealed that T_(C) increased linearly along the growth direction and rthombohedral to tetrahedral phase transition temperature(T_(RT))gradually decreased in the middle part of the ingot.
基金This work was supported by the National Key Research and Development Program of China(2020YFA0707600)the National Key Research and Development Program of China(2020YFC0840800)+1 种基金Beijing Talent Project(2020A50)National Key R&D Program of China(2021ZD0114103).
文摘Introduction:Repeat positive severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)following COVID-19 initial viral clearance(repositivity)poses a public health management challenge.The objective was to determine factors associated with neutralizing antibody(Nab)level and re-positivity among patients infected with a single strain SARS-CoV-2.Methods:During a single strain SARS-CoV-2 cluster in Beijing,China,longitudinal individual clinical,virological,and immunological data were collected from 368 infections from June 13 to September 22,2020.Factors associated with Nab level and re-positivity were analyzed using generalized estimating equations.Results:A total of 353(96%)SARS-CoV-2 infections had demographic,clinical,and laboratory data available.Among the 353 infections,55(15.5%)were re-positive,and blood draws were taken from 346 individuals(98.0%)during hospitalization and/or during the follow-up period.Symptoms were milder for the second-time admission for the re-positives,although 36.4%of re-positives presented with radiographic appearance of pneumonia manifestation.Compared to non-re-positive patients,NAb titers were lower among re-positives;NAb was positively associated with clinical severity.Samples from the lower respiratory tract manifested higher viral load than that from the upper respiratory tract.Multivariable analysis showed re-positivity was positively associated with being female[odd ratio(OR)=1.7,95%confidence interval(CI)1.1–2.8]and being aged<18 years(OR=5.2,95%CI 1.5–18.1);having initially asymptomatic infection(OR=13.7,95%CI 1.6–116.3);and negatively associated with a higher NAb level(OR=0.9,95%CI 0.5–1.7).Conclusions:NAb may be important for sustained viral clearance.Lower respiratory tract infection was associated with higher viral load among all infections when compared to upper respiratory tract infection.Continuous lower respiratory and intermittent upper respiratory viral shedding among COVID-19 infections may occur.
基金This work was supported by the National Key Research and Development Project of China(2020YFC0840800)the National Natural Science Foundation of China(no.31801093).
文摘SARS-CoV-2 has caused over 100 million deaths and continues to spread rapidly around the world.Asymptomatic transmission of SARS-CoV-2 is the Achilles’heel of COVID-19 public health control measures.Phylogenomic data on SARS-CoV-2 could provide more direct information about asymptomatic transmission.In this study,using a novel MINERVA sequencing technology,we traced asymptomatic transmission of COVID-19 patients in Beijing,China.One hundred and seventy-eight close contacts were quarantined,and 14 COVID-19 patients were laboratory confirmed by RT-PCR.We provide direct phylogenomic evidence of asymptomatic transmission by constructing the median joining network in the cluster.These data could help us to determine whether the current symptom-based screening should cover asymptomatic persons.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDB29010102)the National Natural Science Foundation of China(NSFC)(32041010)+4 种基金Beijing Municipal Science&Technology Commission(Z201100007920017)Beijing Municipal Administration of Hospital Clinical Medicine Development of Special Funding Support(ZYLX201802)Beijing Hospital Authority(DFL20191801)the NSFC Outstanding Young Scholars(31822055)the Youth Innovation Promotion Association of CAS(2017122)。
文摘Dear Editor,The coronavirus disease 2019(COVID-19)pandemic is generating a demand for simultaneous vaccine development,which is expected to prevent future outbreaks by eliciting sufficient and protective immunity.
文摘The ongoing coronavirus disease 2019(COVID-19)pandemic caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection has led to over 240 million confirmed infections and severe economic burdens worldwide.Multiple emerging SARS-CoV-2 variants of concern(VOCs)and variants of interest(VOIs)have recently beenidentifiedand are nowspreading internationally,including B.1.1.7(Alpha),B.1.351(Beta),P.1(Gamma),B.1.617(Delta and Kappa),C.37(Lambda),and B.1.621(Mu),all of which appear to bemore easily transmitted(WHO,COVID-19Weekly EpidemiologicalUpdate).Beta andGamma VOCs can seriously impair the protective efficacy of existing vaccines,potentially precluding the possibility of attaining"herd immunity."
基金The National Key Research and Development Program of China(2020YFA0707600)the Scientific Research Project of Youan Hospital,CCMU,2020(BJYAYY-2020YC-01)the National Key Research and Development Program of China(2020YFC0840800).
文摘Few reports are available about prolonged shedding of coronavirus disease(COVID-19)virus,also known as severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),by immunocompetent patients.We report a case of an infected,immunocompetent person with 169 days of COVID-19 virus shedding during which time he had two brief periods when he tested negative for COVID-19 followed by again testing positive.We describe relevant clinical,immunological,and genomic features.We found that continuous and prolonged viral replication and infectivity existed in an immunocompetent COVID-19 patient,despite having high neutralizing antibody titers.
