The Earth’s Free Core Nutation(FCN) causes Earth tides and forced nutation with frequencies close to the FCN that exhibit resonance effects.High-precision superconducting gravimeter(SG) and very long baseline interfe...The Earth’s Free Core Nutation(FCN) causes Earth tides and forced nutation with frequencies close to the FCN that exhibit resonance effects.High-precision superconducting gravimeter(SG) and very long baseline interferometry(VLBI) provide good observation techniques for detecting the FCN parameters.However,some choices in data processing and solution procedures increase the uncertainty of the FCN parameters.In this study,we analyzed the differences and the effectiveness of weight function and ocean tide corrections in the FCN parameter detection using synthetic data,SG data from thirty-one stations,and the 10 celestial pole offset(CPO) series.The results show that significant discrepancies are caused by different computing options for a single SG station.The stacking method,which results in a variation of0.24-5 sidereal days(SDs) in the FCN period(T) and 10^(3)-10^(4) in the quality factor(Q) due to the selection of the weighting function and the ocean tide model(OTM),can effectively suppress this influence.The statistical analysis results of synthetic data shows that although different weight choices,while adjusting the proportion of diurnal tidal waves involved,do not significantly improve the accuracy of fitted FCN parameters from gravity observations.The study evaluated a series of OTMs using the loading correction efficiency.The fitting of FCN parameters can be improved by selecting the mean of appropriate OTMs based on the evaluation results.Through the estimation of the FCN parameters based on the forced nutation,it was found that the weight function P_(1) is more suitable than others,and different CPO series(after 2009) resulted in a difference of 0.4 SDs in the T and of 103 in the Q.We estimated the FCN parameters for SG(T=430.4±1.5 SDs and Q=1.52×10^(4)±2.5×10^(3)) and for VLBI(T=429.8±0.7 SDs,Q=1.88×10^(4)±2.1×10^(3)).展开更多
Modern geodetic technologies such as high-precision ground gravity measurements,satellite gravity measurements,the global navigation satellite system,remote sensing methods,etc.provide rich observation data for monito...Modern geodetic technologies such as high-precision ground gravity measurements,satellite gravity measurements,the global navigation satellite system,remote sensing methods,etc.provide rich observation data for monitoring various geodynamic processes of the global Earth and its surface.The 19th International Symposium on Geodynamics and Earth Tides brought together scientific researchers from 26 countries around the world,shared the application of various measurements in different geoscience issues,covering Earth tidal deformation,oceanic and atmospheric loading effects,earthquake cycle,hydrology,Earth rotation changes,etc.,and provided a precious exchange platform for global peers.展开更多
The acoustic properties of seafloor sediment are essential parameters in the exploration of marine resources,ocean scientific research and ocean engineering.Seafloor sediment samples were collected at the southern U-b...The acoustic properties of seafloor sediment are essential parameters in the exploration of marine resources,ocean scientific research and ocean engineering.Seafloor sediment samples were collected at the southern U-boundary of the South China Sea(SCS),and the acoustic and physical properties were measured in the laboratory.The correlation between physical and sound speed ratio(SSR)was discussed,and SSR-physical property empirical regressions in the Sunda Shelf were established for the first time.Compared with the northern continental shelf of SCS,the Sunda Shelf are mainly silty and sand sediment,and the SSR ranges from 0.9949 to 1.0944,which has higher SSR than the northern continental shelf,implies that the Sunda Shelf is a high SSR area.Since the same kind of sediment has different physical properties,the single physical parameter of sediment cannot fully represent the acoustic properties of sediment,therefore,the multiple parameter prediction model should develop in the future to improve the prediction precision.展开更多
Gravity field is the most basic physical field generated by the material properties of the Earth system.It reflects the spatial distribution,movement and change of materials determined by the interaction and dynamic p...Gravity field is the most basic physical field generated by the material properties of the Earth system.It reflects the spatial distribution,movement and change of materials determined by the interaction and dynamic process inside the Earth.Over the years,a variety of technical means have been used to detect the Earth’s gravity field and supported numerous studies on the global change,resource detection,geological structure movement,water resources change and other related fields of research.Here is part of the progress in surface and marine gravimetry obtained by Chinese geodesy scientists from 2019 to 2023 from the following aspects,including:①Continuous gravity network in Chinese mainland;②Application of superconducting gravity measurement;③Network adjustment for continental-scale gravity survey campaign and data quality control;④Regional time-variable gravity field and its application;⑤Research progress on novel technologies for gravity inversion;⑥Research progress on marine gravity field determination;⑦Application research on marine gravity field.展开更多
Earthquakes perturb both the ocean bottom topography due to displacements of sea floor and the geoid due to mass redistribution, which induces the relative sea level(RSL) change. However, the relative global mean sea ...Earthquakes perturb both the ocean bottom topography due to displacements of sea floor and the geoid due to mass redistribution, which induces the relative sea level(RSL) change. However, the relative global mean sea level(GMSL) change is zero in that sea water mass is conserved. But the absolute GMSL change is not zero because earthquakes displace total ocean mass with respect to the Earth’s center of mass(CM) which remains unchanged after an earthquake. This displacement, i.e. the absolute GMSL change, may be detectable by altimetry since the satellites are orbiting around CM. In this paper, we proposed a method to estimate co-seismic absolute GMSL change caused by earthquakes based on the point dislocation theory for a spherically symmetric, non-rotating, elastic and isotropic(SNREI) Earth.This change can be directly connected to the perturbation of ocean bottom topography. We first computed co-seismic displacements as well as the change in geo-potential and solved the sea level equation to validate the insignificance of the oceans’ feedback, i.e. the loading effect due to RSL change, to co-seismic displacements. The results imply that the loading effect due to RSL change is negligible on displacements while is considerable on geoid. We then computed the absolute GMSL change caused by co-seismic vertical and horizontal displacements by making use of the integrated Green’s function method. The numerical results show that a large earthquake may raise the absolute GMSL by magnitude of sub-millimeter and the recent three large events cause GMSL to rise about one millimeter, in which the contribution from horizontal displacement is non-negligible.展开更多
Objective:This study aimed to investigate the effects of TH/CTS/β-CD microspheres by oral administration on ovalbumin allergic asthma of a rat model.Methods:Spray drying method was applied for preparing the TH/CTS/β...Objective:This study aimed to investigate the effects of TH/CTS/β-CD microspheres by oral administration on ovalbumin allergic asthma of a rat model.Methods:Spray drying method was applied for preparing the TH/CTS/β-CD microspheres,which were used in treatment of asthmatic rats.At a predetermined time,the levels of eosinophil(Eos),protein,lactate dehydrogenase(LDH),aspartate transaminase(AST),glutamic pyruvic transaminase(GPT),and creatinine(Cr)were ascertained by automatic hematology and biochemical analyzers.Lung tissue histology was performed by hematoxylin-eosin staining.Results:No significant differences were found about the contents of Eos in the blood,and the contents of Eos,protein and LDH in the bronchoalveolar lavage fluid between the microsphere-treated and dexamethasone-treated groups,but the levels were lower in both treated groups than in the model group.In the microsphere-treated group,the levels of Cr,AST,and GPT in the serum of rats showed no significant differences compared with the normal group.Based on lung histopathological findings,the microspheres attenuated inflammatory cell infiltration and mucus hypersecretion compared with the model group.Conclusion:This study demonstrated that TH/CTS/β-CD microspheres exerted an anti-inflammatory effect and could serve as a novel promising drug delivery system for asthma treatment.展开更多
Compared with the surface,the deep environment has the advantages of allowing“super-quiet and ultra-clean”-geophysical field observation with low vibration noise and little electromagnetic interference,which are con...Compared with the surface,the deep environment has the advantages of allowing“super-quiet and ultra-clean”-geophysical field observation with low vibration noise and little electromagnetic interference,which are conducive to the realization of long-term and high-precision observation of multi-physical fields,thus enabling the solution of a series of geoscience problems.In the Panyidong Coal Mine,where there are extensive underground tunnels at the depth of 848 m below sea level,we carried out the first deep-underground geophysical observations,including radioactivity,gravity,magnetic,magnetotelluric,background vibration and six-component seismic observations.We concluded from these measurements that(1)the background of deep subsurface gravity noise in the long-period frequency band less than 2 Hz is nearly two orders of magnitude weaker than that in the surface observation environment;(2)the underground electric field is obviously weaker than the surface electric field,and the relatively high frequency of the underground field,greater than 1 Hz,is more than two orders of magnitude weaker than that of the surface electric field;the east-west magnetic field underground is approximately the same as that at the surface;the relatively high-frequency north-south magnetic field underground,below 10 Hz,is at least one order of magnitude lower than that at the surface,showing that the underground has a clean electromagnetic environment;(3)in addition to the highfrequency and single-frequency noises introduced by underground human activities,the deep underground space has a significantly lower background vibration noise than the surface,which is very beneficial to the detection of weak earthquake and gravity signals;and(4)the underground roadway support system built with ferromagnetic material interferes the geomagnetic field.We also found that for deep observation in the“ultra-quiet and ultra-clean”environment,the existing geophysical equipment and observation technology have problems of poor adaptability and insufficient precision as well as data cleaning problems,such as the effective separation of the signal and noise of deep observation data.It is also urgent to interpret and comprehensively utilize these high-precision multi-physics observation data.展开更多
This work investigated the dependence of deformation mechanisms and mechanical properties on cold rolling reductions of the metastable TB8 titanium alloy.Results shown that the crystal orientation of the matrix change...This work investigated the dependence of deformation mechanisms and mechanical properties on cold rolling reductions of the metastable TB8 titanium alloy.Results shown that the crystal orientation of the matrix changes with the increasing level of reduction,leading to the activation of complex deformation mechanisms in the matrix.When the rolling reduction is 10%,the deformation mechanisms are dominated by dislocations and{332}<113>deformation twins.As the reductions increase to 20%-50%,the secondary deformation twinning(SDT)is triggered in primary deformation twins besides the primary kink band is activated.Meanwhile,the secondary kink bands and{332}<113>twins have be observed in the primary kink bands.When the reduction reaches to 60%,the deformation mechanisms are dominated by dislocations and deformation twins.Furthermore,the matrix refined by crisscrossing among the twins,kink bands and other deformation mechanisms during cold rolling,which shortens the dislocation mean free path and then affects the strength and shape of the alloy.The dynamic Hall-Petch effect and the interaction between multi-scale deformed structures control the work hardening behavior of the alloy.展开更多
Dear Editor,Coronavirus Disease 2019(COVID-19)is associated with a variety of neurological complications,including encephalopathy,encephalitis,dementia,and others.1 The pathogenic mechanism of these neurological manif...Dear Editor,Coronavirus Disease 2019(COVID-19)is associated with a variety of neurological complications,including encephalopathy,encephalitis,dementia,and others.1 The pathogenic mechanism of these neurological manifestations remains incompletely understood but may be due to factors such as coagulation problem,immune-mediated response,or direct viral invasion into the central nervous system(CNS).2 We and others previously reported that ancestral SARS-CoV-2 could infect and replicate in human brain organoids.3,4 More recently,SARS-CoV-2 Omicron BA.1 emerged in late 2021 and demonstrated altered virological features including increased immunoevasion and attenuated pathogenicity comparing to SARS-CoV-2 wildtype(WT)and previous variants.5 However,the neuroinvasiveness of Omicron sublineages remain unexplored.Here,we investigated the neuroinvasion and neurotoxicity of Omicron BA.1 and BA.2,and compared the findings with those of SARS-CoV-2 WT and Delta in human forebrain and midbrain organoids.Our results demonstrated that BA.2 replicated more efficiently while triggered lower levels of type I interferon response than that of SARS-CoV-2 WT,Delta,and BA.1 in both human forebrain and midbrain organoids.In addition,BA.2 triggered substantially higher levels of apoptosis in the infected human forebrain and midbrain organoids.Together,these findings suggest that BA.2 may be different from SARS-CoV-2 WT and previous variants in its capacity in targeting and causing diseases in the human brain.展开更多
基金supported by the Open Fund of Hubei Luojia Laboratory (No. 220100033)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB41000000)+1 种基金National Natural Science Foundation of China (Grant Nos. 42174108, 41874094, 42192535 and 42242015)the Young Top-notch Talent Cultivation Program of Hubei Province。
文摘The Earth’s Free Core Nutation(FCN) causes Earth tides and forced nutation with frequencies close to the FCN that exhibit resonance effects.High-precision superconducting gravimeter(SG) and very long baseline interferometry(VLBI) provide good observation techniques for detecting the FCN parameters.However,some choices in data processing and solution procedures increase the uncertainty of the FCN parameters.In this study,we analyzed the differences and the effectiveness of weight function and ocean tide corrections in the FCN parameter detection using synthetic data,SG data from thirty-one stations,and the 10 celestial pole offset(CPO) series.The results show that significant discrepancies are caused by different computing options for a single SG station.The stacking method,which results in a variation of0.24-5 sidereal days(SDs) in the FCN period(T) and 10^(3)-10^(4) in the quality factor(Q) due to the selection of the weighting function and the ocean tide model(OTM),can effectively suppress this influence.The statistical analysis results of synthetic data shows that although different weight choices,while adjusting the proportion of diurnal tidal waves involved,do not significantly improve the accuracy of fitted FCN parameters from gravity observations.The study evaluated a series of OTMs using the loading correction efficiency.The fitting of FCN parameters can be improved by selecting the mean of appropriate OTMs based on the evaluation results.Through the estimation of the FCN parameters based on the forced nutation,it was found that the weight function P_(1) is more suitable than others,and different CPO series(after 2009) resulted in a difference of 0.4 SDs in the T and of 103 in the Q.We estimated the FCN parameters for SG(T=430.4±1.5 SDs and Q=1.52×10^(4)±2.5×10^(3)) and for VLBI(T=429.8±0.7 SDs,Q=1.88×10^(4)±2.1×10^(3)).
基金Major Program of the National Natural Science Foundation of China(42192535).
文摘Modern geodetic technologies such as high-precision ground gravity measurements,satellite gravity measurements,the global navigation satellite system,remote sensing methods,etc.provide rich observation data for monitoring various geodynamic processes of the global Earth and its surface.The 19th International Symposium on Geodynamics and Earth Tides brought together scientific researchers from 26 countries around the world,shared the application of various measurements in different geoscience issues,covering Earth tidal deformation,oceanic and atmospheric loading effects,earthquake cycle,hydrology,Earth rotation changes,etc.,and provided a precious exchange platform for global peers.
基金Supported by the Guangdong Special Support Key Team Program(No.2019BT02H594)the National Key R&D Program of China(No.2021YFF0501202)+5 种基金the Youth Innovation Promotion Association CASthe National Natural Science Foundation of China(Nos.41706045,42176191,41773039,U22A2012)the Rising Star Foundation of the Integrated Research Center for Islands and Reefs Sciences,CAS(No.ZDRW-XH-2021-2-03)the CAS Key Laboratory of Science and Technology on Operational Oceanography Open Project Funding(No.OOST2021-01)the Guangdong Natural Science Foundation(No.2017A030313237)the State Key Laboratory of Acoustics,Chinese Academy of Sciences(Nos.SKLA202007,SKLA202106)。
文摘The acoustic properties of seafloor sediment are essential parameters in the exploration of marine resources,ocean scientific research and ocean engineering.Seafloor sediment samples were collected at the southern U-boundary of the South China Sea(SCS),and the acoustic and physical properties were measured in the laboratory.The correlation between physical and sound speed ratio(SSR)was discussed,and SSR-physical property empirical regressions in the Sunda Shelf were established for the first time.Compared with the northern continental shelf of SCS,the Sunda Shelf are mainly silty and sand sediment,and the SSR ranges from 0.9949 to 1.0944,which has higher SSR than the northern continental shelf,implies that the Sunda Shelf is a high SSR area.Since the same kind of sediment has different physical properties,the single physical parameter of sediment cannot fully represent the acoustic properties of sediment,therefore,the multiple parameter prediction model should develop in the future to improve the prediction precision.
基金Open Fund of Hubei Luojia Laboratory(No.220100033)National Natural Science Foundation of China(Nos.42174108,42192535,42242015)。
文摘Gravity field is the most basic physical field generated by the material properties of the Earth system.It reflects the spatial distribution,movement and change of materials determined by the interaction and dynamic process inside the Earth.Over the years,a variety of technical means have been used to detect the Earth’s gravity field and supported numerous studies on the global change,resource detection,geological structure movement,water resources change and other related fields of research.Here is part of the progress in surface and marine gravimetry obtained by Chinese geodesy scientists from 2019 to 2023 from the following aspects,including:①Continuous gravity network in Chinese mainland;②Application of superconducting gravity measurement;③Network adjustment for continental-scale gravity survey campaign and data quality control;④Regional time-variable gravity field and its application;⑤Research progress on novel technologies for gravity inversion;⑥Research progress on marine gravity field determination;⑦Application research on marine gravity field.
基金financially supported by the "973" project of China (Grant No. 2014CB845902)the NSFC projects(Grant Nos. 41874026, 41374025 and 41621091)
文摘Earthquakes perturb both the ocean bottom topography due to displacements of sea floor and the geoid due to mass redistribution, which induces the relative sea level(RSL) change. However, the relative global mean sea level(GMSL) change is zero in that sea water mass is conserved. But the absolute GMSL change is not zero because earthquakes displace total ocean mass with respect to the Earth’s center of mass(CM) which remains unchanged after an earthquake. This displacement, i.e. the absolute GMSL change, may be detectable by altimetry since the satellites are orbiting around CM. In this paper, we proposed a method to estimate co-seismic absolute GMSL change caused by earthquakes based on the point dislocation theory for a spherically symmetric, non-rotating, elastic and isotropic(SNREI) Earth.This change can be directly connected to the perturbation of ocean bottom topography. We first computed co-seismic displacements as well as the change in geo-potential and solved the sea level equation to validate the insignificance of the oceans’ feedback, i.e. the loading effect due to RSL change, to co-seismic displacements. The results imply that the loading effect due to RSL change is negligible on displacements while is considerable on geoid. We then computed the absolute GMSL change caused by co-seismic vertical and horizontal displacements by making use of the integrated Green’s function method. The numerical results show that a large earthquake may raise the absolute GMSL by magnitude of sub-millimeter and the recent three large events cause GMSL to rise about one millimeter, in which the contribution from horizontal displacement is non-negligible.
基金the foundation for visiting scholar abroad in Weifang Medical University,National Natural Science Foundation of China(No.81973671,81774125)Weifang Science and Technology Development Plan Project(2018YX060).
文摘Objective:This study aimed to investigate the effects of TH/CTS/β-CD microspheres by oral administration on ovalbumin allergic asthma of a rat model.Methods:Spray drying method was applied for preparing the TH/CTS/β-CD microspheres,which were used in treatment of asthmatic rats.At a predetermined time,the levels of eosinophil(Eos),protein,lactate dehydrogenase(LDH),aspartate transaminase(AST),glutamic pyruvic transaminase(GPT),and creatinine(Cr)were ascertained by automatic hematology and biochemical analyzers.Lung tissue histology was performed by hematoxylin-eosin staining.Results:No significant differences were found about the contents of Eos in the blood,and the contents of Eos,protein and LDH in the bronchoalveolar lavage fluid between the microsphere-treated and dexamethasone-treated groups,but the levels were lower in both treated groups than in the model group.In the microsphere-treated group,the levels of Cr,AST,and GPT in the serum of rats showed no significant differences compared with the normal group.Based on lung histopathological findings,the microspheres attenuated inflammatory cell infiltration and mucus hypersecretion compared with the model group.Conclusion:This study demonstrated that TH/CTS/β-CD microspheres exerted an anti-inflammatory effect and could serve as a novel promising drug delivery system for asthma treatment.
基金supported by the National Natural Science Foundation of China (Grant Nos.62127815,42150201,U1839208)
文摘Compared with the surface,the deep environment has the advantages of allowing“super-quiet and ultra-clean”-geophysical field observation with low vibration noise and little electromagnetic interference,which are conducive to the realization of long-term and high-precision observation of multi-physical fields,thus enabling the solution of a series of geoscience problems.In the Panyidong Coal Mine,where there are extensive underground tunnels at the depth of 848 m below sea level,we carried out the first deep-underground geophysical observations,including radioactivity,gravity,magnetic,magnetotelluric,background vibration and six-component seismic observations.We concluded from these measurements that(1)the background of deep subsurface gravity noise in the long-period frequency band less than 2 Hz is nearly two orders of magnitude weaker than that in the surface observation environment;(2)the underground electric field is obviously weaker than the surface electric field,and the relatively high frequency of the underground field,greater than 1 Hz,is more than two orders of magnitude weaker than that of the surface electric field;the east-west magnetic field underground is approximately the same as that at the surface;the relatively high-frequency north-south magnetic field underground,below 10 Hz,is at least one order of magnitude lower than that at the surface,showing that the underground has a clean electromagnetic environment;(3)in addition to the highfrequency and single-frequency noises introduced by underground human activities,the deep underground space has a significantly lower background vibration noise than the surface,which is very beneficial to the detection of weak earthquake and gravity signals;and(4)the underground roadway support system built with ferromagnetic material interferes the geomagnetic field.We also found that for deep observation in the“ultra-quiet and ultra-clean”environment,the existing geophysical equipment and observation technology have problems of poor adaptability and insufficient precision as well as data cleaning problems,such as the effective separation of the signal and noise of deep observation data.It is also urgent to interpret and comprehensively utilize these high-precision multi-physics observation data.
基金financially supported by the National Natural Science Foundation of China(Nos.52071185 and 51861029)the Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(No.NJYT19-B25)+2 种基金the Inner Mongolia Natural Science Foundation(No.2020MS05034)the Key Research and Development Program of Shaanxi(No.2019GY-151)the National Natural Science Foundation of China(No.51901193)。
文摘This work investigated the dependence of deformation mechanisms and mechanical properties on cold rolling reductions of the metastable TB8 titanium alloy.Results shown that the crystal orientation of the matrix changes with the increasing level of reduction,leading to the activation of complex deformation mechanisms in the matrix.When the rolling reduction is 10%,the deformation mechanisms are dominated by dislocations and{332}<113>deformation twins.As the reductions increase to 20%-50%,the secondary deformation twinning(SDT)is triggered in primary deformation twins besides the primary kink band is activated.Meanwhile,the secondary kink bands and{332}<113>twins have be observed in the primary kink bands.When the reduction reaches to 60%,the deformation mechanisms are dominated by dislocations and deformation twins.Furthermore,the matrix refined by crisscrossing among the twins,kink bands and other deformation mechanisms during cold rolling,which shortens the dislocation mean free path and then affects the strength and shape of the alloy.The dynamic Hall-Petch effect and the interaction between multi-scale deformed structures control the work hardening behavior of the alloy.
基金Health and Medical Research Fund(CID-HKU1–5,COVID1903010–7 and-14,and 20190652)Food and Health Bureau,the Government of the Hong Kong Special Administrative Region,General Research Fund(14104321,14109920,14121618,14169717,17118621,and 17123920)+10 种基金Collaborative Research Fund(C7060-21GF)Theme-Based Research Scheme(T11-709/21-N),Research Grants Council,the Government of the Hong Kong Special Administrative RegionHealth@InnoHK,Innovation and Technology Commission,the Government of the Hong Kong Special Administrative RegionNational Natural Science Foundation of China Excellent Young Scientists Fund(Hong Kong and Macao)(32122001)the Consultancy Service for Enhancing Laboratory Surveillance of Emerging Infectious Diseases and Research Capability on Antimicrobial Resistance for Department of Health of the Hong Kong Special Administrative Region GovernmentEmergency Collaborative Project(EKPG22-01)of Guangzhou LaboratoryEmergency COVID-19 Project(2021YFC0866100),Major Projects on Public Security,National Key Research and Development ProgramSanming Project of Medicine in Shenzhen,China(SZSM201911014)the High Level-Hospital Program,Health Commission of Guangdong Province,Chinathe University of Hong Kong Outstanding Young Researcher Awardthe University of Hong Kong Research Output Prize(Li Ka Shing Faculty of Medicine).
文摘Dear Editor,Coronavirus Disease 2019(COVID-19)is associated with a variety of neurological complications,including encephalopathy,encephalitis,dementia,and others.1 The pathogenic mechanism of these neurological manifestations remains incompletely understood but may be due to factors such as coagulation problem,immune-mediated response,or direct viral invasion into the central nervous system(CNS).2 We and others previously reported that ancestral SARS-CoV-2 could infect and replicate in human brain organoids.3,4 More recently,SARS-CoV-2 Omicron BA.1 emerged in late 2021 and demonstrated altered virological features including increased immunoevasion and attenuated pathogenicity comparing to SARS-CoV-2 wildtype(WT)and previous variants.5 However,the neuroinvasiveness of Omicron sublineages remain unexplored.Here,we investigated the neuroinvasion and neurotoxicity of Omicron BA.1 and BA.2,and compared the findings with those of SARS-CoV-2 WT and Delta in human forebrain and midbrain organoids.Our results demonstrated that BA.2 replicated more efficiently while triggered lower levels of type I interferon response than that of SARS-CoV-2 WT,Delta,and BA.1 in both human forebrain and midbrain organoids.In addition,BA.2 triggered substantially higher levels of apoptosis in the infected human forebrain and midbrain organoids.Together,these findings suggest that BA.2 may be different from SARS-CoV-2 WT and previous variants in its capacity in targeting and causing diseases in the human brain.
