Understanding water dynamics under the effect of climatic conditions is important to improve water sustainability over the medium-and long-term.Clay content can affect soil hydrothermal properties,and hence modify wat...Understanding water dynamics under the effect of climatic conditions is important to improve water sustainability over the medium-and long-term.Clay content can affect soil hydrothermal properties,and hence modify water and heat exchange between soil and atmosphere,e.g.evapotranspiration and infiltration.This work aims to develop a numerical approach to explore the influence of clay content on soil hydrothermal response to the timely climatic conditions in the Lake Chad region,Sahel Region of west-central Africa.The meteorological information at the studied points,i.e.points A and B with a clay content of 8.3%and 25%,during the year 2008 is collected from ERA5-Land hourly data.The numerical results allow for understanding the effect of clay content on the hydrothermal response of the surface soil layer.Specifically,the soil surface temperature under point A is lower than that under point B during the dry season due to the dominant effect of heat conduction.However,the converse tendency is observed during the wet season because of the combined effect of heat conduction and latent heat.The variations of soil volumetric water content are closely related to the timely interaction between the soil and atmosphere,in addition to the hydrothermal properties of soil.Moreover,the outcomes of this work improve the understanding of the heat and water dynamics under the effect of climatic conditions and clay content,and provide further insights into the potential water protection in arid and semi-arid regions in the future.展开更多
Against the current background of global climate change, the study of variations in the soil carbon pool and its controlling factors may aid in the evaluation of soil＇s role in the mitigation or enhancement of greenh...Against the current background of global climate change, the study of variations in the soil carbon pool and its controlling factors may aid in the evaluation of soil＇s role in the mitigation or enhancement of greenhouse gas. This paper studies spatial and temporal variation in the soil carbon pool and their controlling factors in the southern Song-nen Plain in Heilongjiang Province, using soil data collected over two distinct periods by the Multi-purpose Regional Geochemical Survey in 2005-2007, and another soil survey conducted in 1982-1990. The study area is a carbon source of 1479 t/km2 and in the past 20 years, from the 1980s until 2005, the practical carbon emission from the soil was 0.12 Gt. Temperature, which has been found to be linearly correlated to soil organic carbon, is the domi- nant climatologic factor controlling soil organic carbon contents. Our study shows that in the relevant area and time period the potential loss of soil organic carbon caused by rising temperatures was 0.10 Gt, the potential soil carbon emission resulting from land-use change was 0.09 Gt, and the combined potential loss of soil carbon （0.19 Gt） caused by warming and land-use change is comparable to that of fossil fuel combustion （0.21 Gt）. Due to the time delay in soil carbon pool variation, there is still 0.07 Gt in the potential emission caused by warming and land-use change that will be gradually released in the future.展开更多
Employing the Unit Soil Carbon Amount （USCA） approach, soil carbon storage was calcu- lated across the Northeast Plain of China based on the Multi-purpose Regional Geochemical Survey conducted in 2004-2006 （MRGS）....Employing the Unit Soil Carbon Amount （USCA） approach, soil carbon storage was calcu- lated across the Northeast Plain of China based on the Multi-purpose Regional Geochemical Survey conducted in 2004-2006 （MRGS）. The results indicated that the soil organic carbon （SOC） storage in topsoil （0-0.2 m）, subsoil （0-1 m） and deep soil （0-1.8 m） was 768.1 Mt, 2978.4 Mt and 3729.2 Mt with densities of 3327.8 t/km^2, 12,904.7 t/km^2 and 16,157.5 t/km^2, respectively. These values were consistent with national averages, whereas the soil carbon densities showed a clear increasing trend from the southern area of the Northeast Plain （Liaoning）, to the middle （Jilin） and the northern Plain （Heilongjiang） -- particularly in terms of topsoil carbon density, which increased from 2284.2, to 3436.7 and 3861.5 t/kin2, respectively. In comparison to carbon data obtained from the Second National Soil Survey in 1984--1986 （SNSS）, the topsoil SOC storage values from the MRGS were found to have decreased by 320.59 Mt （29.4%）, with an average annual decline of 16.0 Mt （1.73%） over the 20 years. In the southern, middle and northern areas of the plain, soil carbon densities decreased by 1060.6 t/km^2, 1646.4 t/kin2 and 1300.2 t/km^2, respectively, with an average value of 1389.0 t/km^2 for the whole plain. These findings indicate that the decrease in soil carbon density varied according to the different ecosystems and land-use types. Therefore, ratios of soil carbon density were calculated in order to study the carbon dynamic balance between ecosystems, and to further explore distribution characteristics, as well as the sequestration potential of SOC.展开更多
Bacterial pathogens have evolved various mechanisms to modulate host immune responses for successful infection. In this study, RNA- sequencing technology was used to analyze the responses of human monocytes THP1 to Ye...Bacterial pathogens have evolved various mechanisms to modulate host immune responses for successful infection. In this study, RNA- sequencing technology was used to analyze the responses of human monocytes THP1 to Yersinia pestis infection. Over 6000 genes were differentially expressed over the 12 h infection. Kinetic responses of pathogen recognition receptor signaling pathways, apoptosis, antigen processing, and presentation pathway and coagulation system were analyzed in detail. Among them, RIG-I-like receptor （RLR） signaling pathway, which was established for antiviral defense, was significantly affected. Mice lacking MAVS, the adaptor of the RLR signaling pathway, were less sensitive to infection and exhibited lower IFN-13 production, higher Thl-type cytokines IFN-γ and IL-12 production, and lower Th2-type cytokines IL-4 and IL-13 production in the serum compared with wild-type mice. Moreover, infection of pathogenic bacteria other than E pestis also altered the expression of the RLR pathway, suggesting that the response of RLR pathway to bacterial infection is a universal mechanism.展开更多
The soil-atmosphere interaction was investigated through laboratory testing,field monitoring and numerical monitoring.In the laboratory,the soil water evaporation mechanisms were studied using an environmental chamber...The soil-atmosphere interaction was investigated through laboratory testing,field monitoring and numerical monitoring.In the laboratory,the soil water evaporation mechanisms were studied using an environmental chamber equipped with a large number of sensors for controlling both the air parameters and soil parameters.Both sand and clay were considered.In case of sand,a dry layer could be formed during evaporation in the near surface zone where the suction corresponded to the residual volumetric water content.The evaporative surface was situated at a depth where the soil temperature was the lowest.In case of clay,soil cracking occurred,changing the evaporative surface from one-dimensional to three-dimensional nature.The suctionbased evaporation model was adapted to take these phenomena into account by adopting a function of dry layer evolution in the case of sand and by adopting a surface crack ratio and a retative humidity ratio in the case of clay.In the field,the volumetric water content,and the suction as well as the runoff were monitored for an embankment constructed with lime/cement treated soils.It appeared that using precipitation data only did not allow a correct description of the variations of volumetric water content and suction inside the soils,the consideration of water evaporation being essential.It was possible to use a correlation between precipiration and runoff.The hydraulic conductivity was found to be a key parameter controlling the variations of volumetric water content and suction.For the numerical modelling,a fully coupled thermohydraulic model was developed,allowing analyzing the changes in temperature,volumetric water content and suction of soil,with the upper boundary conditions at the interface between soil and atmosphere determined using meteorological data.Comparison between simulations and measurements showed the performance of such numerical approach.展开更多
Dear Editor,The family Totiviridae contains non-enveloped,doublestranded RNA viruses with genomes of approximately 4.6–7 kbp in length.These totiviruses are classified into five genera:Totivirus,Victorivirus,Trichomo...Dear Editor,The family Totiviridae contains non-enveloped,doublestranded RNA viruses with genomes of approximately 4.6–7 kbp in length.These totiviruses are classified into five genera:Totivirus,Victorivirus,Trichomonasvirus,Giardiavirus,and Leishmaniavirus(Nibert 2007).They are associated with latent infections of fungal or protozoan hosts(Li et al.2020).Recently,a few totiviruses have been identified and shown to have unexpected host distributions,including insects,plants.展开更多
The coronavirus disease 2019(COVID-19)pandemic caused by frequently mutating severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has had a worldwide impact.However,detailed data on the potential aerosol transmi...The coronavirus disease 2019(COVID-19)pandemic caused by frequently mutating severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has had a worldwide impact.However,detailed data on the potential aerosol transmission of SARS-CoV-2 in real-world and controlled laboratory settings remain sparse.During the COVID-19 pandemic in Shanghai,China in 2022,samples were collected in a Fangcang shelter hospital,a large-scale temporary hospital rapidly built by converting the existing National Exhibition and Convention Center(Shanghai)into a health care facility.Aerosol samples at different sites and intervals around patients and in public areas,surface samples,and pharyngeal swab samples from corresponding patients were included.Samples were tested for SARS-CoV-2 using real-time quantitative polymerase chain reaction(RT-qPCR)assays,followed by sequencing if the cycle threshold(Ct)value was<30.The positivity rate for SARS-CoV-2 in aerosol samples was high in contaminated zones(37.5%,104/277),especially around the bed(41.2%,68/165)and near ventilation inlets(45.2%,14/31).The prevalence of SARS-CoV-2 around the bed,public areas,and air inlets of exhaust vents fluctuated and was closely related to the positivity rate among patients at corresponding sampling sites.Some surface samples of different personal protective equipment from medical staff had high positivity rates.Sixty sequences of joined ORF1ab and spike genes obtained from sixty samples represented two main clusters of Omicron SARS-CoV-2.There was consistency in virus sequences from the same patient and their environment,and the detected virus sequences matched those of virus strains in circulation during the collection periods,which indicated a high likelihood of cross-contamination in the Fangcang shelter hospital.In summary,the results provide a quantitative and real landscape of the aerosol transmission of SARS-CoV-2 and a patient-centered view of contamination in large and enclosed spaces and offer a useful guide for taking targeted measures to avoid nosocomial infections during the management of SARS-CoV-2 or other respiratory virus diseases in a Fangcang shelter hospital.展开更多
Colorectal cancer(CRC)is the third leading cancer globally.Metagenomics has been widely used to analyze the association between the gut microbiota and CRC based on bacterial genus-or species-level comparisons,providin...Colorectal cancer(CRC)is the third leading cancer globally.Metagenomics has been widely used to analyze the association between the gut microbiota and CRC based on bacterial genus-or species-level comparisons,providing evidence of dysbiosis in CRC development.However,this kind of analysis is unable to provide strain-level information for understanding the individual role of a species in CRC.Here,we used culturomics to isolate CRC mucosal samples and selected 158 Escherichia coli strains to reveal their differences in both genomics and functions by means of phylogenetic analysis and inflammatory induction based on cell and animal experiments.Through genomic comparison,these strains were divided into five phylogroups.The representative strains of each phylogroup significantly induced different levels of cytokine secretion by human leukemic monocyte(THP-1 cell)-based Transwell and animal experiments.Further bioinformatic analysis revealed different profiles of single-nucleotide polymorphisms,genes,and metabolic pathways in the different phylogroups,which can improve the current understanding of the phenotypic differences between these strains.The strain differences revealed in both genomics and functions indicate that the microbiota’s function at the strain level should be investigated in order to understand the interacting mechanisms between hosts and gut bacteria.展开更多
The establishment of energy balance equation is necessary to study the thermo-mechanical properties of unsaturated soils.To solve this equation,the determination of two fundamental parameters as volumetric specific pa...The establishment of energy balance equation is necessary to study the thermo-mechanical properties of unsaturated soils.To solve this equation,the determination of two fundamental parameters as volumetric specific parameter and thermal conductivity coefficient is essential.In this paper,the effective thermal conductivity coefficient of dry soil grain is analyzed for soils with different compositions,and the thermo-mechanical properties of porous media with water and gas are studied by considering the soil water retention curve（SWRC）.Different methods,i.e.volumetric average method,self-consistent method,Hashin-Strikman method,are employed to calculate thermal conductivity coefficients,and a new method is proposed to determine the thermo-mechanical parameters.Comparison of the results obtained by different methods shows that the proposed method is in a good agreement with the experimental results and is suitable for describing the main properties of the thermo-mechanical behaviors of soils.The relationship between the SWRC and the seepage curve is further studied by the natural proportional rule.The characteristics of the SWRC,its differential coefficient and the seepage curve,are investigated by considering the physico-mechanical mechanism;the limit scopes of the indices of the SWRC and the seepage curve are also given.展开更多
Impact statement We have developed a manually curated online reference database,DANMEL(http://124.239.252.254/danmel/),that addresses the lack of accurate dissection and annotation of the genetic structures of mobile ...Impact statement We have developed a manually curated online reference database,DANMEL(http://124.239.252.254/danmel/),that addresses the lack of accurate dissection and annotation of the genetic structures of mobile genetic elements(MGEs)with genes for drug resistance.DANMEL contains accurately annotated and genetically dissected reference MGEs covering 5 categories and 135 subcategories/subfamilies of MGEs.Further,DANMEL provides a detailed guide on how to precisely annotate MGEs.DANMEL also provides SEARCH/BLAST functions to facilitate finding reference MGEs.Overall,DANMEL will aid researchers to conduct in-depth genetic analysis of sequenced bacterial MGEs with drug-resistance genes and further facilitate a better understanding of bacterial MGEs associated with drug resistance at a genomic level.展开更多
The gut microbiota is involved in host responses to high altitude.However,the dynamics of intestinal microecology and their association with altitude-related illness are poorly understood.Here,we used a rat model of h...The gut microbiota is involved in host responses to high altitude.However,the dynamics of intestinal microecology and their association with altitude-related illness are poorly understood.Here,we used a rat model of hypobaric hypoxia challenge to mimic plateau exposure and monitored the gut microbiome,short-chain fatty acids(SCFAs),and bile acids(BAs)over 28 d.We identified weight loss,polycythemia,and pathological cardiac hypertrophy in hypoxic rats,accompanied by a large compositional shift in the gut microbiota,which is mainly driven by the bacterial families of Prevotellaceae,Porphyromonadaceae,and Streptococcaceae.The aberrant gut microbiota was characterized by increased abundance of the Parabacteroides,Alistipes,and Lactococcus genera and a larger Bacteroides to Prevotella ratio.Trans-omics analyses showed that the gut microbiome was significantly correlated with the metabolic abnormalities of SCFAs and BAs in feces,suggesting an interaction network remodeling of the microbiome-metabolome after the hypobaric hypoxia challenge.Interestingly,the transplantation of fecal microbiota significantly increased the diversity of the gut microbiota,partially inhibited the increased abundance of the Bacteroides and Alistipes genera,restored the decrease of plasma propionate,and moderately ameliorated cardiac hypertrophy in hypoxic rats.Our results provide an insight into the longitudinal changes in intestinal microecology during the hypobaric hypoxia challenge.Abnormalities in the gut microbiota and microbial metabolites contribute to the development of high-altitude heart disease in rats.展开更多
Dear Editor,Synthetic DNA is emerging as a new data storage medium with high density and durable preservation capability potential(Ceze et al., 2019;Yazdi et al., 2015), thus enhancing the security of data stored in D...Dear Editor,Synthetic DNA is emerging as a new data storage medium with high density and durable preservation capability potential(Ceze et al., 2019;Yazdi et al., 2015), thus enhancing the security of data stored in DNA is particularly important(Cherian et al., 2013;El-Zoghabi et al., 2013;Kalsi et al.,2018).展开更多
The gut microbiota plays a key role in obesity and related metabolic disorders, and multiple factors including diet, host genotype, and age regulate it. Many studies have examined the contribution of extrinsic factors...The gut microbiota plays a key role in obesity and related metabolic disorders, and multiple factors including diet, host genotype, and age regulate it. Many studies have examined the contribution of extrinsic factors to the regulation of the gut microbiota, but the importance of the host genetic constitution cannot be ignored, lnterleukin 17A （lL-17A）, a pro-inflammatory cytokine, is important in the defense against infection and diseases. Here, we investigated the association among IL-17, a high-fat diet （HFD）, and the gut microbiota. Mice deficient in 1L-17A were resistant to diet-induced obesity and related diseases. Compared with the I1-17a^-/1 mice, wild-type （WT） mice challenged with HFD showed obvious weight fluctuations, such as those seen in type 2 diabetes, and hematological changes similar to those associated with metabolic syndrome. However, housing WT mice and Il-17a^-/- mice together signifi- cantly alleviated these symptoms in the WT mice. A metagenomic analysis of the mouse feces indicated that the microbial community compositions of these two groups differed before HFD feeding. The HFD mediated shifts in the gut microbial compositions, which were associated with the mouse phenotypes. We also identified potentially beneficial and harmful species present during this period, and drew net- works of the most abundant species. A functional analysis indicated pathway changes in the WT and I1-17a^- /- mice when fed the HFD. Collectively, these data underscore the importance of the host factor IL-17A in shaping and regulating the gut microbiota, which conversely, influences the host health.展开更多
The highly pathogenic and readily transmissible SARS-CoV-2 has caused a global coronavirus pandemic,urgently requiring effective countermeasures against its rapid expansion.All available vaccine platforms are being us...The highly pathogenic and readily transmissible SARS-CoV-2 has caused a global coronavirus pandemic,urgently requiring effective countermeasures against its rapid expansion.All available vaccine platforms are being used to generate safe and effective COVID-19 vaccines.Here,we generated a live-attenuated candidate vaccine strain by serial passaging of a SARSCoV-2 clinical isolate in Vero cells.展开更多
The hydro-mechanical behaviour of compacted expansive Romainville clay was investigated.The soil was air-dried,crushed,and passed through a 2 mm sieve before being statically compacted to a dry density of 1.35 Mg/m3.T...The hydro-mechanical behaviour of compacted expansive Romainville clay was investigated.The soil was air-dried,crushed,and passed through a 2 mm sieve before being statically compacted to a dry density of 1.35 Mg/m3.The mechanical behaviour was investigated by tests in oedometer with controlled suction using the vapor equilibrium technique(suction s=0,9,39,and 110 MPa).The vertical stress was applied in the range of 0-800 kPa.The experimental results are shown as follows:1)wetting-induced swelling was higher at lower vertical stresses;2)the vertical stress under which no swelling occurred during water flooding was estimated at 60 kPa,which can be considered as the swelling pressure of the soil tested;3)the soil compressibility(changes of volume upon stress increases)was strongly influenced by the soil suction:the lower the suction,the higher the compressibility.The hydraulic behaviour was investigated using a large-scale infiltration chamber(800mm×1000 mm in section and 1000mm high).The large size of the soil column allowed bttrying the volumetric water content sensors(ThetaProbe)without significantly affecting the water transfer and the soil swelling during infiltration.The soil suction was monitored along the soil height(every 100 mm)using various relative humidity sensors and psychrometers.In the infiltration test,water was kept on the soil surface and changes in suction and volumetric water content were monitored for 338 d.The wetting front has reached the bottom of the soil column at the end of the test.The data from the simultaneous monitoring of suction and water content were used to determine the water retention curve and the unsaturated hydraulic conductivity using the instantaneous profile method.It has been observed that the soil water retention curve depends on the soil depth;that is to be related to the soil depthdependent swelling.The unsaturated hydraulic conductiv-ity was found to be quite low,comprised between 3×10-11m/s(at saturated state)and 10-14m/s(at about 100 MPa suction).展开更多
Zero-mode waveguides have become important tools for the detection of single molecules.There are still,however,serious challenges because large molecules need to be packed into nano-holes.To circumvent this problem,we...Zero-mode waveguides have become important tools for the detection of single molecules.There are still,however,serious challenges because large molecules need to be packed into nano-holes.To circumvent this problem,we investigate and numerically simulate a novel planar sub-wavelength 3-dimension(3D)structure,which is named as near-field spot.It enables the detection of a single molecule in highly concentrated solutions.The near-field spot can produce evanescent waves at the dielectric/water interface,which exponentially decay as they travel away from the dielectric/water interface.These evanescent waves are keys for the detection of fluorescently tagged single molecules.A numerical simulation of the proposed device shows that the performance is comparable with a zero-mode waveguide.Additional degrees-of-freedom,however,can potentially supersede its performance.展开更多
We study the existence of positive solutions to boundary value problems for one- dimensional p-Laplacian under some conditions about the first eigenvalues correspon- ding to the relevant operators by the fixed point t...We study the existence of positive solutions to boundary value problems for one- dimensional p-Laplacian under some conditions about the first eigenvalues correspon- ding to the relevant operators by the fixed point theory. The main difficulties are the computation of fixed point index and the subadditivity for positively 1-homogeneous operator.展开更多
基金the National Natural Science Foundation of China(Grant No.42207171).
文摘Understanding water dynamics under the effect of climatic conditions is important to improve water sustainability over the medium-and long-term.Clay content can affect soil hydrothermal properties,and hence modify water and heat exchange between soil and atmosphere,e.g.evapotranspiration and infiltration.This work aims to develop a numerical approach to explore the influence of clay content on soil hydrothermal response to the timely climatic conditions in the Lake Chad region,Sahel Region of west-central Africa.The meteorological information at the studied points,i.e.points A and B with a clay content of 8.3%and 25%,during the year 2008 is collected from ERA5-Land hourly data.The numerical results allow for understanding the effect of clay content on the hydrothermal response of the surface soil layer.Specifically,the soil surface temperature under point A is lower than that under point B during the dry season due to the dominant effect of heat conduction.However,the converse tendency is observed during the wet season because of the combined effect of heat conduction and latent heat.The variations of soil volumetric water content are closely related to the timely interaction between the soil and atmosphere,in addition to the hydrothermal properties of soil.Moreover,the outcomes of this work improve the understanding of the heat and water dynamics under the effect of climatic conditions and clay content,and provide further insights into the potential water protection in arid and semi-arid regions in the future.
基金funded by Commonweal Trade Scientific Research from the Ministry of Land and Resources of the People's Republic of China
文摘Against the current background of global climate change, the study of variations in the soil carbon pool and its controlling factors may aid in the evaluation of soil＇s role in the mitigation or enhancement of greenhouse gas. This paper studies spatial and temporal variation in the soil carbon pool and their controlling factors in the southern Song-nen Plain in Heilongjiang Province, using soil data collected over two distinct periods by the Multi-purpose Regional Geochemical Survey in 2005-2007, and another soil survey conducted in 1982-1990. The study area is a carbon source of 1479 t/km2 and in the past 20 years, from the 1980s until 2005, the practical carbon emission from the soil was 0.12 Gt. Temperature, which has been found to be linearly correlated to soil organic carbon, is the domi- nant climatologic factor controlling soil organic carbon contents. Our study shows that in the relevant area and time period the potential loss of soil organic carbon caused by rising temperatures was 0.10 Gt, the potential soil carbon emission resulting from land-use change was 0.09 Gt, and the combined potential loss of soil carbon （0.19 Gt） caused by warming and land-use change is comparable to that of fossil fuel combustion （0.21 Gt）. Due to the time delay in soil carbon pool variation, there is still 0.07 Gt in the potential emission caused by warming and land-use change that will be gradually released in the future.
基金funded by the program"National Soil Current Situation Survey and Pollution Prevention"from the China Ministry of Finance
文摘Employing the Unit Soil Carbon Amount （USCA） approach, soil carbon storage was calcu- lated across the Northeast Plain of China based on the Multi-purpose Regional Geochemical Survey conducted in 2004-2006 （MRGS）. The results indicated that the soil organic carbon （SOC） storage in topsoil （0-0.2 m）, subsoil （0-1 m） and deep soil （0-1.8 m） was 768.1 Mt, 2978.4 Mt and 3729.2 Mt with densities of 3327.8 t/km^2, 12,904.7 t/km^2 and 16,157.5 t/km^2, respectively. These values were consistent with national averages, whereas the soil carbon densities showed a clear increasing trend from the southern area of the Northeast Plain （Liaoning）, to the middle （Jilin） and the northern Plain （Heilongjiang） -- particularly in terms of topsoil carbon density, which increased from 2284.2, to 3436.7 and 3861.5 t/kin2, respectively. In comparison to carbon data obtained from the Second National Soil Survey in 1984--1986 （SNSS）, the topsoil SOC storage values from the MRGS were found to have decreased by 320.59 Mt （29.4%）, with an average annual decline of 16.0 Mt （1.73%） over the 20 years. In the southern, middle and northern areas of the plain, soil carbon densities decreased by 1060.6 t/km^2, 1646.4 t/kin2 and 1300.2 t/km^2, respectively, with an average value of 1389.0 t/km^2 for the whole plain. These findings indicate that the decrease in soil carbon density varied according to the different ecosystems and land-use types. Therefore, ratios of soil carbon density were calculated in order to study the carbon dynamic balance between ecosystems, and to further explore distribution characteristics, as well as the sequestration potential of SOC.
基金supported by the National Basic Research Program of China(Nos.2012CB518704 and 2013CB910804)the National Natural Science Foundation of China(No.31170122)the Basic Research Programs of Science and Technology Department Foundation of QingHai Province(No.2013-Z-748)
文摘Bacterial pathogens have evolved various mechanisms to modulate host immune responses for successful infection. In this study, RNA- sequencing technology was used to analyze the responses of human monocytes THP1 to Yersinia pestis infection. Over 6000 genes were differentially expressed over the 12 h infection. Kinetic responses of pathogen recognition receptor signaling pathways, apoptosis, antigen processing, and presentation pathway and coagulation system were analyzed in detail. Among them, RIG-I-like receptor （RLR） signaling pathway, which was established for antiviral defense, was significantly affected. Mice lacking MAVS, the adaptor of the RLR signaling pathway, were less sensitive to infection and exhibited lower IFN-13 production, higher Thl-type cytokines IFN-γ and IL-12 production, and lower Th2-type cytokines IL-4 and IL-13 production in the serum compared with wild-type mice. Moreover, infection of pathogenic bacteria other than E pestis also altered the expression of the RLR pathway, suggesting that the response of RLR pathway to bacterial infection is a universal mechanism.
基金the French Research Agency(ANR)within the Project Ter DOUEST ANR-07-PCGU-006-10。
文摘The soil-atmosphere interaction was investigated through laboratory testing,field monitoring and numerical monitoring.In the laboratory,the soil water evaporation mechanisms were studied using an environmental chamber equipped with a large number of sensors for controlling both the air parameters and soil parameters.Both sand and clay were considered.In case of sand,a dry layer could be formed during evaporation in the near surface zone where the suction corresponded to the residual volumetric water content.The evaporative surface was situated at a depth where the soil temperature was the lowest.In case of clay,soil cracking occurred,changing the evaporative surface from one-dimensional to three-dimensional nature.The suctionbased evaporation model was adapted to take these phenomena into account by adopting a function of dry layer evolution in the case of sand and by adopting a surface crack ratio and a retative humidity ratio in the case of clay.In the field,the volumetric water content,and the suction as well as the runoff were monitored for an embankment constructed with lime/cement treated soils.It appeared that using precipitation data only did not allow a correct description of the variations of volumetric water content and suction inside the soils,the consideration of water evaporation being essential.It was possible to use a correlation between precipiration and runoff.The hydraulic conductivity was found to be a key parameter controlling the variations of volumetric water content and suction.For the numerical modelling,a fully coupled thermohydraulic model was developed,allowing analyzing the changes in temperature,volumetric water content and suction of soil,with the upper boundary conditions at the interface between soil and atmosphere determined using meteorological data.Comparison between simulations and measurements showed the performance of such numerical approach.
基金supported by grants from the National Key R&D Program of China(2017YFC1200802)National Science and Technology Major Project of China(2018ZX10711001003-001)+1 种基金the State Key Laboratories Program of China(SKLPBS1817)the Yunnan Health Training Project of High Level Talents(D-201604)
文摘Dear Editor,The family Totiviridae contains non-enveloped,doublestranded RNA viruses with genomes of approximately 4.6–7 kbp in length.These totiviruses are classified into five genera:Totivirus,Victorivirus,Trichomonasvirus,Giardiavirus,and Leishmaniavirus(Nibert 2007).They are associated with latent infections of fungal or protozoan hosts(Li et al.2020).Recently,a few totiviruses have been identified and shown to have unexpected host distributions,including insects,plants.
基金supported by National Key Research and Development Program of China(2019YFC1200500)supported by Emergency Key Program of Guangzhou Laboratory(EKPG21-01)supported by National Natural Science Foundation of China(32070166)。
文摘The coronavirus disease 2019(COVID-19)pandemic caused by frequently mutating severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has had a worldwide impact.However,detailed data on the potential aerosol transmission of SARS-CoV-2 in real-world and controlled laboratory settings remain sparse.During the COVID-19 pandemic in Shanghai,China in 2022,samples were collected in a Fangcang shelter hospital,a large-scale temporary hospital rapidly built by converting the existing National Exhibition and Convention Center(Shanghai)into a health care facility.Aerosol samples at different sites and intervals around patients and in public areas,surface samples,and pharyngeal swab samples from corresponding patients were included.Samples were tested for SARS-CoV-2 using real-time quantitative polymerase chain reaction(RT-qPCR)assays,followed by sequencing if the cycle threshold(Ct)value was<30.The positivity rate for SARS-CoV-2 in aerosol samples was high in contaminated zones(37.5%,104/277),especially around the bed(41.2%,68/165)and near ventilation inlets(45.2%,14/31).The prevalence of SARS-CoV-2 around the bed,public areas,and air inlets of exhaust vents fluctuated and was closely related to the positivity rate among patients at corresponding sampling sites.Some surface samples of different personal protective equipment from medical staff had high positivity rates.Sixty sequences of joined ORF1ab and spike genes obtained from sixty samples represented two main clusters of Omicron SARS-CoV-2.There was consistency in virus sequences from the same patient and their environment,and the detected virus sequences matched those of virus strains in circulation during the collection periods,which indicated a high likelihood of cross-contamination in the Fangcang shelter hospital.In summary,the results provide a quantitative and real landscape of the aerosol transmission of SARS-CoV-2 and a patient-centered view of contamination in large and enclosed spaces and offer a useful guide for taking targeted measures to avoid nosocomial infections during the management of SARS-CoV-2 or other respiratory virus diseases in a Fangcang shelter hospital.
基金supported by the National Natural Science Foundation for Key Programs of China(81790632)the National Natural Science Foundation of China(31970863)the Innovation Leader Team Program of Guangzhou(201809010014)。
文摘Colorectal cancer(CRC)is the third leading cancer globally.Metagenomics has been widely used to analyze the association between the gut microbiota and CRC based on bacterial genus-or species-level comparisons,providing evidence of dysbiosis in CRC development.However,this kind of analysis is unable to provide strain-level information for understanding the individual role of a species in CRC.Here,we used culturomics to isolate CRC mucosal samples and selected 158 Escherichia coli strains to reveal their differences in both genomics and functions by means of phylogenetic analysis and inflammatory induction based on cell and animal experiments.Through genomic comparison,these strains were divided into five phylogroups.The representative strains of each phylogroup significantly induced different levels of cytokine secretion by human leukemic monocyte(THP-1 cell)-based Transwell and animal experiments.Further bioinformatic analysis revealed different profiles of single-nucleotide polymorphisms,genes,and metabolic pathways in the different phylogroups,which can improve the current understanding of the phenotypic differences between these strains.The strain differences revealed in both genomics and functions indicate that the microbiota’s function at the strain level should be investigated in order to understand the interacting mechanisms between hosts and gut bacteria.
基金Supported by the National Natural Science Foundation of China(50779030,50879044,2008BAB29B03)the National Defenses Bureau(838)
文摘The establishment of energy balance equation is necessary to study the thermo-mechanical properties of unsaturated soils.To solve this equation,the determination of two fundamental parameters as volumetric specific parameter and thermal conductivity coefficient is essential.In this paper,the effective thermal conductivity coefficient of dry soil grain is analyzed for soils with different compositions,and the thermo-mechanical properties of porous media with water and gas are studied by considering the soil water retention curve（SWRC）.Different methods,i.e.volumetric average method,self-consistent method,Hashin-Strikman method,are employed to calculate thermal conductivity coefficients,and a new method is proposed to determine the thermo-mechanical parameters.Comparison of the results obtained by different methods shows that the proposed method is in a good agreement with the experimental results and is suitable for describing the main properties of the thermo-mechanical behaviors of soils.The relationship between the SWRC and the seepage curve is further studied by the natural proportional rule.The characteristics of the SWRC,its differential coefficient and the seepage curve,are investigated by considering the physico-mechanical mechanism;the limit scopes of the indices of the SWRC and the seepage curve are also given.
文摘Impact statement We have developed a manually curated online reference database,DANMEL(http://124.239.252.254/danmel/),that addresses the lack of accurate dissection and annotation of the genetic structures of mobile genetic elements(MGEs)with genes for drug resistance.DANMEL contains accurately annotated and genetically dissected reference MGEs covering 5 categories and 135 subcategories/subfamilies of MGEs.Further,DANMEL provides a detailed guide on how to precisely annotate MGEs.DANMEL also provides SEARCH/BLAST functions to facilitate finding reference MGEs.Overall,DANMEL will aid researchers to conduct in-depth genetic analysis of sequenced bacterial MGEs with drug-resistance genes and further facilitate a better understanding of bacterial MGEs associated with drug resistance at a genomic level.
基金supported by the National Natural Science Foundation of China(81790632,31970863,and 31970088)the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2020YFA0509600)。
文摘The gut microbiota is involved in host responses to high altitude.However,the dynamics of intestinal microecology and their association with altitude-related illness are poorly understood.Here,we used a rat model of hypobaric hypoxia challenge to mimic plateau exposure and monitored the gut microbiome,short-chain fatty acids(SCFAs),and bile acids(BAs)over 28 d.We identified weight loss,polycythemia,and pathological cardiac hypertrophy in hypoxic rats,accompanied by a large compositional shift in the gut microbiota,which is mainly driven by the bacterial families of Prevotellaceae,Porphyromonadaceae,and Streptococcaceae.The aberrant gut microbiota was characterized by increased abundance of the Parabacteroides,Alistipes,and Lactococcus genera and a larger Bacteroides to Prevotella ratio.Trans-omics analyses showed that the gut microbiome was significantly correlated with the metabolic abnormalities of SCFAs and BAs in feces,suggesting an interaction network remodeling of the microbiome-metabolome after the hypobaric hypoxia challenge.Interestingly,the transplantation of fecal microbiota significantly increased the diversity of the gut microbiota,partially inhibited the increased abundance of the Bacteroides and Alistipes genera,restored the decrease of plasma propionate,and moderately ameliorated cardiac hypertrophy in hypoxic rats.Our results provide an insight into the longitudinal changes in intestinal microecology during the hypobaric hypoxia challenge.Abnormalities in the gut microbiota and microbial metabolites contribute to the development of high-altitude heart disease in rats.
文摘Dear Editor,Synthetic DNA is emerging as a new data storage medium with high density and durable preservation capability potential(Ceze et al., 2019;Yazdi et al., 2015), thus enhancing the security of data stored in DNA is particularly important(Cherian et al., 2013;El-Zoghabi et al., 2013;Kalsi et al.,2018).
基金supported by the National High Technology Research and Development Program (2015AA020702)
文摘The gut microbiota plays a key role in obesity and related metabolic disorders, and multiple factors including diet, host genotype, and age regulate it. Many studies have examined the contribution of extrinsic factors to the regulation of the gut microbiota, but the importance of the host genetic constitution cannot be ignored, lnterleukin 17A （lL-17A）, a pro-inflammatory cytokine, is important in the defense against infection and diseases. Here, we investigated the association among IL-17, a high-fat diet （HFD）, and the gut microbiota. Mice deficient in 1L-17A were resistant to diet-induced obesity and related diseases. Compared with the I1-17a^-/1 mice, wild-type （WT） mice challenged with HFD showed obvious weight fluctuations, such as those seen in type 2 diabetes, and hematological changes similar to those associated with metabolic syndrome. However, housing WT mice and Il-17a^-/- mice together signifi- cantly alleviated these symptoms in the WT mice. A metagenomic analysis of the mouse feces indicated that the microbial community compositions of these two groups differed before HFD feeding. The HFD mediated shifts in the gut microbial compositions, which were associated with the mouse phenotypes. We also identified potentially beneficial and harmful species present during this period, and drew net- works of the most abundant species. A functional analysis indicated pathway changes in the WT and I1-17a^- /- mice when fed the HFD. Collectively, these data underscore the importance of the host factor IL-17A in shaping and regulating the gut microbiota, which conversely, influences the host health.
基金This work was supported by the National Key Research and Development Program of China(No.2020YFC0840900,2018YFA0900801 and 2020YFA0707500)the Strategic Priority Research Program(XDB29010000,XDB37030000),CAS(YSBR-010)+5 种基金the Emergency Key Programof Guangzhou Laboratory(No.EKPG21-09)the Beijing Municipal Science and Technology Project(No.Z201100001020004,Z201100005420017)the National Natural Science Foundation of China(No.82171820,No.12034006,and No.81921005)C.-F.Q.was supported by the National Science Fund for Distinguished Young Scholars(81925025)the Innovative Research Group(81621005)from the NSFCthe Innovation Fund forMedical Sciences(2019-I2 M-5-049)from the Chinese Academy of Medical Sciences.
文摘The highly pathogenic and readily transmissible SARS-CoV-2 has caused a global coronavirus pandemic,urgently requiring effective countermeasures against its rapid expansion.All available vaccine platforms are being used to generate safe and effective COVID-19 vaccines.Here,we generated a live-attenuated candidate vaccine strain by serial passaging of a SARSCoV-2 clinical isolate in Vero cells.
基金This work was supported by the Chutianscholar program.
文摘The hydro-mechanical behaviour of compacted expansive Romainville clay was investigated.The soil was air-dried,crushed,and passed through a 2 mm sieve before being statically compacted to a dry density of 1.35 Mg/m3.The mechanical behaviour was investigated by tests in oedometer with controlled suction using the vapor equilibrium technique(suction s=0,9,39,and 110 MPa).The vertical stress was applied in the range of 0-800 kPa.The experimental results are shown as follows:1)wetting-induced swelling was higher at lower vertical stresses;2)the vertical stress under which no swelling occurred during water flooding was estimated at 60 kPa,which can be considered as the swelling pressure of the soil tested;3)the soil compressibility(changes of volume upon stress increases)was strongly influenced by the soil suction:the lower the suction,the higher the compressibility.The hydraulic behaviour was investigated using a large-scale infiltration chamber(800mm×1000 mm in section and 1000mm high).The large size of the soil column allowed bttrying the volumetric water content sensors(ThetaProbe)without significantly affecting the water transfer and the soil swelling during infiltration.The soil suction was monitored along the soil height(every 100 mm)using various relative humidity sensors and psychrometers.In the infiltration test,water was kept on the soil surface and changes in suction and volumetric water content were monitored for 338 d.The wetting front has reached the bottom of the soil column at the end of the test.The data from the simultaneous monitoring of suction and water content were used to determine the water retention curve and the unsaturated hydraulic conductivity using the instantaneous profile method.It has been observed that the soil water retention curve depends on the soil depth;that is to be related to the soil depthdependent swelling.The unsaturated hydraulic conductiv-ity was found to be quite low,comprised between 3×10-11m/s(at saturated state)and 10-14m/s(at about 100 MPa suction).
基金support of Southeast University for carrying out this research.This work was financially supported by Southeast University Postdoctoral Science Foundation Grant program,China(Grant No.2242018R20013),the National Key Research and Development Program of China(Grant No.2017YFA0205700),the National Natural Science Foundation of China(Grant No.61850410528),the Fundamental Research Funds for the Central Universities,and the Fundamental Research Project of Shenzhen Science&Technology Innovation Committee(Grant No.JCYJ20180306174552939).
文摘Zero-mode waveguides have become important tools for the detection of single molecules.There are still,however,serious challenges because large molecules need to be packed into nano-holes.To circumvent this problem,we investigate and numerically simulate a novel planar sub-wavelength 3-dimension(3D)structure,which is named as near-field spot.It enables the detection of a single molecule in highly concentrated solutions.The near-field spot can produce evanescent waves at the dielectric/water interface,which exponentially decay as they travel away from the dielectric/water interface.These evanescent waves are keys for the detection of fluorescently tagged single molecules.A numerical simulation of the proposed device shows that the performance is comparable with a zero-mode waveguide.Additional degrees-of-freedom,however,can potentially supersede its performance.
基金supported by the National Natural Science Foundation of China(11371221,11071141)the Specialized Research Foundation for the Doctoral Program of Higher Educationof China(20123705110001)the Program for Scientific Research Innovation Team in Colleges and Universities of Shandong Province and Foundation of SDUST
文摘We study the existence of positive solutions to boundary value problems for one- dimensional p-Laplacian under some conditions about the first eigenvalues correspon- ding to the relevant operators by the fixed point theory. The main difficulties are the computation of fixed point index and the subadditivity for positively 1-homogeneous operator.
