Objective： To explore whether single and fused monochromatic images can improve liver tumor detection and delineation by single source dual energy CT （ssDECT） in patients with hepatocellular carcinoma （HCC） durin...Objective： To explore whether single and fused monochromatic images can improve liver tumor detection and delineation by single source dual energy CT （ssDECT） in patients with hepatocellular carcinoma （HCC） during arterial phase. Methods： Fifty-seven patients with HCC who underwent ssDECT scanning at Beijing Cancer Hospital were enrolled retrospectively. Twenty-one sets of monochromatic images from 40 to 140 keV were reconstructed at 5 keV intervals in arterial phase. The optimal contrast-noise ratio （CNR） monochromatic images of the liver tumor and the lowest-noise monochromatic images were selected for image fusion. We evaluated the image quality of the optimal-CNR monochromatic images, the lowest-noise monochromatic images and the fused monochromatic images, respectively. The evaluation indicators included the spatial resolution of the anatomical structure, the noise level, the contrast and CNR of the tumor. Results： In arterial phase, the anatomical structure of the liver can be displayed most clearly in the 65-keV monochromatic images, with the lowest image noise. The optimal-CNR monochromatic images of HCC tumor were 50-keV monochromatic images in which the internal structural features of the liver tumors were displayed most clearly and meticulously. For tumor detection, the fused monochromatic images and the 50-keV monochromatic images had similar performances, and were more sensitive than 65-keV monochromatic images. Conclusions： We achieved good arterial phase images by fusing the optimal-CNR monochromatic images of the HCC tumor and the lowest-noise monochromatic images. The fused images displayed liver tumors and anatomical structures more clearly, which is potentially helpful for identifying more and smaller HCC tumors.展开更多
Partial substitution of synthetic nitrogen(N)with organic fertilizers(PSOF)is of great significance in improving soil ecosystem functions in systems that have deteriorated due to the excessive application of chemical ...Partial substitution of synthetic nitrogen(N)with organic fertilizers(PSOF)is of great significance in improving soil ecosystem functions in systems that have deteriorated due to the excessive application of chemical N fertilizer.However,existing studies typically focus on individual soil functions,neglecting the fact that multiple functions occur simultaneously.It remains unclear how PSOF influences multiple soil functions and whether these impacts are related to soil microbial communities.Here,we examined the impacts of partial substitutions(25%–50%)of chemical N fertilizer with organic form(pig manure or municipal sludge)in a vegetable field on soil multifunctionality,by measuring a range of soil functions involving primary production(vegetable yield and quality),nutrient cycling(soil enzyme activities,ammonia volatilization,N leaching,and N runoff),and climate regulation(soil organic carbon sequestration and nitrous oxide emission).We observed that PSOF improved soil multifunctionality,with a 50%substitution of chemical N fertilizer with pig manure being the best management practice;the result was strongly related to the diversities and network complexities of bacteria and fungi.Random forest analysis further revealed that soil multifunctionality was best explained by the bacterial-fungal network complexity,followed by available phosphorus level and bacterial diversity.The PSOF also shifted the composition of bacterial and fungal communities,with increased relative abundances of dominant bacteria phyla,such as Bacteroidetes,Gemmatimonadetes,and Myxococcota,and fungal phyla,such as Basidiomycota and Olpidiomycota.The observed increases in soil multifunctionality were consistent with significant increases in the relative abundances of keystone taxa such as Blastocladiomycota,Chaetomiaceae,and Nocardiopsaceae.Together,these findings indicate that PSOF can enhance interactions within and among microbial communities and that such practices have the potential to improve soil ecosystem multifunctionality and contribute to the development of sustainable agriculture.展开更多
Antimony(Sb) is a toxic metalloid, and its pollution has become a global environmental problem as a result of its extensive use and corresponding Sb-mining activities. The toxicity and mobility of Sb strongly depend o...Antimony(Sb) is a toxic metalloid, and its pollution has become a global environmental problem as a result of its extensive use and corresponding Sb-mining activities. The toxicity and mobility of Sb strongly depend on its chemical speciation. In this review, we summarize the current knowledge on the biogeochemical processes(including emission, distribution,speciation, redox, metabolism and toxicity) that trigger the mobilization and transformation of Sb from pollution sources to the surrounding environment. Natural phenomena such as weathering, biological activity and volcanic activity, together with anthropogenic inputs, are responsible for the emission of Sb into the environment. Sb emitted in the environment can adsorb and undergo redox reactions on organic or inorganic environmental media, thus changing its existing form and exerting toxic effects on the ecosystem. This review is based on a careful and systematic collection of the latest papers during 2010–2017 and our research results, and it illustrates the fate and ecological effects of Sb in the environment.展开更多
Humic substances(HS),which are defined as a series of highly acidic,relatively high-molecular-weight,and yellow to black colored substances formed during the decay and transformation of plant and microbial remains,ubi...Humic substances(HS),which are defined as a series of highly acidic,relatively high-molecular-weight,and yellow to black colored substances formed during the decay and transformation of plant and microbial remains,ubiquitously occur in nature.Humic substances represent the largest stable organic carbon pool in terrestrial environments and are the central characteristic of the soil.However,the validity of the HS concept and the justification of their extraction procedure have been recently debated.Here,we argue that the traditional humic paradigm is still relevant.Humic substances are distinctive and complex because the extracted HS formed during the humification are chemically distinct from their precursors and are heterogeneous among soils.By reviewing the concept,formation pathways,and stabilization of HS,we propose that the key question facing soil scientists is whether HS are soil microbial residues or unique synthesized compounds.Without revealing the distinctiveness of HS,it is impossible to address this question,as the structure,composition,and reactivity of HS are still poorly known owing to the heterogeneity and geographical variability of HS and the limits of the currently available analytical techniques.In our view,the distinctiveness of HS is fundamental to the soil,and thus further studies should be focused on revealing the distinctiveness of HS and explaining why HS hold this distinctiveness.展开更多
The impacts of biochar addition with nitrogen fertilizer(Urea-N)on greenhouse gas(GHG)fluxes and grain yields are not comprehensively understood.Therefore,we designed a field experiment in an intensive rice-wheat crop...The impacts of biochar addition with nitrogen fertilizer(Urea-N)on greenhouse gas(GHG)fluxes and grain yields are not comprehensively understood.Therefore,we designed a field experiment in an intensive rice-wheat cropping system located in the Taihu Lake region of China and measured CH4 and N_(2)O emissions for 2 consecutive years to examine the impacts of biochar combined with N-fertilizer on rice production and GHG flux.Three field experimental treatments were designed:(1)no N-fertilizer application(N0);(2)270 kg N ha^(−1) application(N270);and(3)270 kg N-fertilizer ha^(−1) plus 25 t ha^(−1) biochar application(N270+C).We found that,compared with urea application alone,biochar applied with Urea-N fertilizer increased N use efficiency(NUE)and resulted in more stable growth of rice yield.In addition,biochar addition increased CH4 emissions by 0.5-37.5%on average during the two consecutive rice-growing seasons,and decreased N_(2)O-N loss by~16.7%.During the first growing season,biochar addition did not significantly affect the global warming potential(GWPt)or the greenhouse gas intensity(GHGI)of rice production(p>0.05).By contrast,during the second rice-growing season,biochar application significantly increased GWPt and GHGI by 28.9%and 18.8%,respectively,mainly because of increased CH_(4) emissions.Our results suggest that biochar amendment could improve grain yields and NUE,and increased soil GWPt,resulting in a higher potential environmental cost,but that biochar additions enhance exogenous carbon sequestration by the soil,which could offset the increases in GHG emissions.展开更多
Background:The new emerging avian influenza A H7N9 virus,causing severe human infection with a mortality rate of around 41%.This study aims to provide a novel treatment option for the prevention and control of H7N9.Me...Background:The new emerging avian influenza A H7N9 virus,causing severe human infection with a mortality rate of around 41%.This study aims to provide a novel treatment option for the prevention and control of H7N9.Methods:H7 hemagglutinin(HA)-specific B cells were isolated from peripheral blood plasma cells of the patients previously infected by H7N9 in Jiangsu Province,China.The human monoclonal antibodies(mAbs)were generated by amplification and cloning of these HA-specific B cells.First,all human mAbs were screened for binding activity by enzyme-linked immunosorbent assay.Then,those mAbs,exhibiting potent affinity to recognize H7 HAs were further evaluated by hemagglutination-inhibiting(HAI)and microneutralizationin vitro assays.Finally,the lead mAb candidate was selected and tested against the lethal challenge of the H7N9 virus using murine models.Results:The mAb 6-137 was able to recognize a panel of H7 HAs with high affinity but not HA of other subtypes,including H1N1 and H3N2.The mAb 6-137 can efficiently inhibit the HA activity in the inactivated H7N9 virus and neutralize 100 tissue culture infectious dose 50(TCID_(50))of H7N9 virus(influenza A/Nanjing/1/2013)invitro,with neutralizing activity as low as 78 ng/mL.In addition,the mAb 6-137 protected the mice against the lethal challenge of H7N9 prophylactically and therapeutically.Conclusion:The mAb 6-137 could be an effective antibody as a prophylactic or therapeutic biological treatment for the H7N9 exposure or infection.展开更多
Many ocean transportation hub systems consist of two container ports that share the container handling business in the area. The container flow passing through a port is the main measurement of the port＇s competitive...Many ocean transportation hub systems consist of two container ports that share the container handling business in the area. The container flow passing through a port is the main measurement of the port＇s competitiveness. In this paper we adopt a Hotelling model to study the container port competition in a so-called ＂dual gateway-port system＂. The system contains two ports and two terminals, one belonging to each port. The two governments in which the two ports are located compete on cargo fees and the two terminals determine service price and service quality. We study two models with different levels of competition between the terminals. In the ftrst model, the two terminals are owned by two different operators and in the second model, the two terminals are centralized under one operator. The second model exists in practice but is not well studied in the literature. We derive the cargo fee, terminal service price, and service quality equilibria for these two models. We investigate the competition outcome sensitivity with a numerical study. The numerical results reveal that governments prefer terminals to compete with each other. If the terminals do not have competitive advantages in their service quality, then terminal centralization brings more profits to the terminal operator than the competition case.展开更多
Using 15N tracer technique,we investigated the potential rates of denitrification,anaerobic ammonium oxidation,dis-similatory nitrate reduction to ammonium(DNRA),and their partitioning among nitrate reduction,as well ...Using 15N tracer technique,we investigated the potential rates of denitrification,anaerobic ammonium oxidation,dis-similatory nitrate reduction to ammonium(DNRA),and their partitioning among nitrate reduction,as well as the N_(2)O emission rates in a paddy soil receiving various biochar(0%,0.03%,0.1%,0.5%,and 1.0%;w/w)and straw(0.1%)over six consecutive years.Results showed that except for the 1.0%amendment treatment,biochar significantly(P<0.05)increased denitrification rates by 10.19‒75.96%compared with non-biochar amended treatment,and that biochar significantly(P<0.05)increased DNRA rates by 1.63‒6.84 folds relative to non-biochar amended treatment.Conse-quently,biochar shifted more NO3-partitioning toward DNRA process,as suggested by the increased DNRA/(denitri-fication+DNRA)ratios from 1.60 to 13.18%.On the other hand,biochar significantly(P<0.05)reduced N_(2)O emission rates by 61.86-97.65%accompanied by a significant decrease in N_(2)O/(N_(2)O+N_(2))ratios(65.29-98.39%),indicating bio-char amendment facilitated the reduction of N_(2)O to N_(2).The promoting effects of biochar on DNRA rates and DNRA/(denitrification+DNRA)ratios were attributed to the increased carbon availability and the altered nitrate reducer communities.Collectively,our study suggests that biochar amendment in the paddy soil is helpful for N conservation by favoring nitrate partitioning toward DNRA process,which deepens our understanding of how biochar mediates N cycling in the paddy field.展开更多
基金supported by the National Basic Research Program of China (973 Program) (Grant No. 2011CB707705)National Natural Science Foundation of China (Grant No. 81371715+1 种基金 81201215)the Capital Characteristic Clinical Application Research (Grant No. Z121107001012115)
文摘Objective： To explore whether single and fused monochromatic images can improve liver tumor detection and delineation by single source dual energy CT （ssDECT） in patients with hepatocellular carcinoma （HCC） during arterial phase. Methods： Fifty-seven patients with HCC who underwent ssDECT scanning at Beijing Cancer Hospital were enrolled retrospectively. Twenty-one sets of monochromatic images from 40 to 140 keV were reconstructed at 5 keV intervals in arterial phase. The optimal contrast-noise ratio （CNR） monochromatic images of the liver tumor and the lowest-noise monochromatic images were selected for image fusion. We evaluated the image quality of the optimal-CNR monochromatic images, the lowest-noise monochromatic images and the fused monochromatic images, respectively. The evaluation indicators included the spatial resolution of the anatomical structure, the noise level, the contrast and CNR of the tumor. Results： In arterial phase, the anatomical structure of the liver can be displayed most clearly in the 65-keV monochromatic images, with the lowest image noise. The optimal-CNR monochromatic images of HCC tumor were 50-keV monochromatic images in which the internal structural features of the liver tumors were displayed most clearly and meticulously. For tumor detection, the fused monochromatic images and the 50-keV monochromatic images had similar performances, and were more sensitive than 65-keV monochromatic images. Conclusions： We achieved good arterial phase images by fusing the optimal-CNR monochromatic images of the HCC tumor and the lowest-noise monochromatic images. The fused images displayed liver tumors and anatomical structures more clearly, which is potentially helpful for identifying more and smaller HCC tumors.
基金supported by the National Natural Science Foundation of China(Nos.41961124004,42207361,and42061124001)。
文摘Partial substitution of synthetic nitrogen(N)with organic fertilizers(PSOF)is of great significance in improving soil ecosystem functions in systems that have deteriorated due to the excessive application of chemical N fertilizer.However,existing studies typically focus on individual soil functions,neglecting the fact that multiple functions occur simultaneously.It remains unclear how PSOF influences multiple soil functions and whether these impacts are related to soil microbial communities.Here,we examined the impacts of partial substitutions(25%–50%)of chemical N fertilizer with organic form(pig manure or municipal sludge)in a vegetable field on soil multifunctionality,by measuring a range of soil functions involving primary production(vegetable yield and quality),nutrient cycling(soil enzyme activities,ammonia volatilization,N leaching,and N runoff),and climate regulation(soil organic carbon sequestration and nitrous oxide emission).We observed that PSOF improved soil multifunctionality,with a 50%substitution of chemical N fertilizer with pig manure being the best management practice;the result was strongly related to the diversities and network complexities of bacteria and fungi.Random forest analysis further revealed that soil multifunctionality was best explained by the bacterial-fungal network complexity,followed by available phosphorus level and bacterial diversity.The PSOF also shifted the composition of bacterial and fungal communities,with increased relative abundances of dominant bacteria phyla,such as Bacteroidetes,Gemmatimonadetes,and Myxococcota,and fungal phyla,such as Basidiomycota and Olpidiomycota.The observed increases in soil multifunctionality were consistent with significant increases in the relative abundances of keystone taxa such as Blastocladiomycota,Chaetomiaceae,and Nocardiopsaceae.Together,these findings indicate that PSOF can enhance interactions within and among microbial communities and that such practices have the potential to improve soil ecosystem multifunctionality and contribute to the development of sustainable agriculture.
基金supported by the National Natural Science Foundation of China (Nos.21477008,21677014,U1706217)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (No.51721093)the Interdiscipline Research Funds of Beijing Normal University (No.312231103)
文摘Antimony(Sb) is a toxic metalloid, and its pollution has become a global environmental problem as a result of its extensive use and corresponding Sb-mining activities. The toxicity and mobility of Sb strongly depend on its chemical speciation. In this review, we summarize the current knowledge on the biogeochemical processes(including emission, distribution,speciation, redox, metabolism and toxicity) that trigger the mobilization and transformation of Sb from pollution sources to the surrounding environment. Natural phenomena such as weathering, biological activity and volcanic activity, together with anthropogenic inputs, are responsible for the emission of Sb into the environment. Sb emitted in the environment can adsorb and undergo redox reactions on organic or inorganic environmental media, thus changing its existing form and exerting toxic effects on the ecosystem. This review is based on a careful and systematic collection of the latest papers during 2010–2017 and our research results, and it illustrates the fate and ecological effects of Sb in the environment.
基金supported by the National Natural Science Foundation of China(Nos.41571231 and 41201221)the National Key Research and Development Program of China(No.2016YFD0200304)+3 种基金the Scientific Instrument and Equipment Development Project of Chinese Academy Sciences(CAS)(No.YJKYYQ20170058)the Natural Science Foundation of Jiangsu Province,China(No.BK2012496)the Youth Innovation Promotion Association,CAS(No.2017362)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.19KJB180010)。
文摘Humic substances(HS),which are defined as a series of highly acidic,relatively high-molecular-weight,and yellow to black colored substances formed during the decay and transformation of plant and microbial remains,ubiquitously occur in nature.Humic substances represent the largest stable organic carbon pool in terrestrial environments and are the central characteristic of the soil.However,the validity of the HS concept and the justification of their extraction procedure have been recently debated.Here,we argue that the traditional humic paradigm is still relevant.Humic substances are distinctive and complex because the extracted HS formed during the humification are chemically distinct from their precursors and are heterogeneous among soils.By reviewing the concept,formation pathways,and stabilization of HS,we propose that the key question facing soil scientists is whether HS are soil microbial residues or unique synthesized compounds.Without revealing the distinctiveness of HS,it is impossible to address this question,as the structure,composition,and reactivity of HS are still poorly known owing to the heterogeneity and geographical variability of HS and the limits of the currently available analytical techniques.In our view,the distinctiveness of HS is fundamental to the soil,and thus further studies should be focused on revealing the distinctiveness of HS and explaining why HS hold this distinctiveness.
基金the National Natural Science Foundation of China(no.41807104)the Suzhou Agricultural Science and Technology Innovation Project(SNG2018099)the Scientific Instrument and Equipment Development Project of CAS(YJKYYQ20170058).
文摘The impacts of biochar addition with nitrogen fertilizer(Urea-N)on greenhouse gas(GHG)fluxes and grain yields are not comprehensively understood.Therefore,we designed a field experiment in an intensive rice-wheat cropping system located in the Taihu Lake region of China and measured CH4 and N_(2)O emissions for 2 consecutive years to examine the impacts of biochar combined with N-fertilizer on rice production and GHG flux.Three field experimental treatments were designed:(1)no N-fertilizer application(N0);(2)270 kg N ha^(−1) application(N270);and(3)270 kg N-fertilizer ha^(−1) plus 25 t ha^(−1) biochar application(N270+C).We found that,compared with urea application alone,biochar applied with Urea-N fertilizer increased N use efficiency(NUE)and resulted in more stable growth of rice yield.In addition,biochar addition increased CH4 emissions by 0.5-37.5%on average during the two consecutive rice-growing seasons,and decreased N_(2)O-N loss by~16.7%.During the first growing season,biochar addition did not significantly affect the global warming potential(GWPt)or the greenhouse gas intensity(GHGI)of rice production(p>0.05).By contrast,during the second rice-growing season,biochar application significantly increased GWPt and GHGI by 28.9%and 18.8%,respectively,mainly because of increased CH_(4) emissions.Our results suggest that biochar amendment could improve grain yields and NUE,and increased soil GWPt,resulting in a higher potential environmental cost,but that biochar additions enhance exogenous carbon sequestration by the soil,which could offset the increases in GHG emissions.
基金National Natural Science Foundation for Youth,China(No.81501793)。
文摘Background:The new emerging avian influenza A H7N9 virus,causing severe human infection with a mortality rate of around 41%.This study aims to provide a novel treatment option for the prevention and control of H7N9.Methods:H7 hemagglutinin(HA)-specific B cells were isolated from peripheral blood plasma cells of the patients previously infected by H7N9 in Jiangsu Province,China.The human monoclonal antibodies(mAbs)were generated by amplification and cloning of these HA-specific B cells.First,all human mAbs were screened for binding activity by enzyme-linked immunosorbent assay.Then,those mAbs,exhibiting potent affinity to recognize H7 HAs were further evaluated by hemagglutination-inhibiting(HAI)and microneutralizationin vitro assays.Finally,the lead mAb candidate was selected and tested against the lethal challenge of the H7N9 virus using murine models.Results:The mAb 6-137 was able to recognize a panel of H7 HAs with high affinity but not HA of other subtypes,including H1N1 and H3N2.The mAb 6-137 can efficiently inhibit the HA activity in the inactivated H7N9 virus and neutralize 100 tissue culture infectious dose 50(TCID_(50))of H7N9 virus(influenza A/Nanjing/1/2013)invitro,with neutralizing activity as low as 78 ng/mL.In addition,the mAb 6-137 protected the mice against the lethal challenge of H7N9 prophylactically and therapeutically.Conclusion:The mAb 6-137 could be an effective antibody as a prophylactic or therapeutic biological treatment for the H7N9 exposure or infection.
基金The authors appreciate the anonymous referees and the editor for their help to improve the quality of the paper. This paper was partially supported by the National Natural Science Foundation of China, NSFC Nos. 71001073, 71302109, 71471118, the Humanities and Social Sciences Foundation of Ministry of Education of China （No. 14YJC630096）, the Distinguished University Young Scholar Program of Guangdong Province （No. Yq2013140）, the Fundamental Research Funds for the Central Universities （No. 15JNQM028） and Natural Science Foundation of SZU （Grant Nos. 201422 and 827000074）.
文摘Many ocean transportation hub systems consist of two container ports that share the container handling business in the area. The container flow passing through a port is the main measurement of the port＇s competitiveness. In this paper we adopt a Hotelling model to study the container port competition in a so-called ＂dual gateway-port system＂. The system contains two ports and two terminals, one belonging to each port. The two governments in which the two ports are located compete on cargo fees and the two terminals determine service price and service quality. We study two models with different levels of competition between the terminals. In the ftrst model, the two terminals are owned by two different operators and in the second model, the two terminals are centralized under one operator. The second model exists in practice but is not well studied in the literature. We derive the cargo fee, terminal service price, and service quality equilibria for these two models. We investigate the competition outcome sensitivity with a numerical study. The numerical results reveal that governments prefer terminals to compete with each other. If the terminals do not have competitive advantages in their service quality, then terminal centralization brings more profits to the terminal operator than the competition case.
基金the National Natural Science Foundation of China(No.U20A20113 and 42177303)the National Key Research and Development Program of China(No.2021YFD1700802).
文摘Using 15N tracer technique,we investigated the potential rates of denitrification,anaerobic ammonium oxidation,dis-similatory nitrate reduction to ammonium(DNRA),and their partitioning among nitrate reduction,as well as the N_(2)O emission rates in a paddy soil receiving various biochar(0%,0.03%,0.1%,0.5%,and 1.0%;w/w)and straw(0.1%)over six consecutive years.Results showed that except for the 1.0%amendment treatment,biochar significantly(P<0.05)increased denitrification rates by 10.19‒75.96%compared with non-biochar amended treatment,and that biochar significantly(P<0.05)increased DNRA rates by 1.63‒6.84 folds relative to non-biochar amended treatment.Conse-quently,biochar shifted more NO3-partitioning toward DNRA process,as suggested by the increased DNRA/(denitri-fication+DNRA)ratios from 1.60 to 13.18%.On the other hand,biochar significantly(P<0.05)reduced N_(2)O emission rates by 61.86-97.65%accompanied by a significant decrease in N_(2)O/(N_(2)O+N_(2))ratios(65.29-98.39%),indicating bio-char amendment facilitated the reduction of N_(2)O to N_(2).The promoting effects of biochar on DNRA rates and DNRA/(denitrification+DNRA)ratios were attributed to the increased carbon availability and the altered nitrate reducer communities.Collectively,our study suggests that biochar amendment in the paddy soil is helpful for N conservation by favoring nitrate partitioning toward DNRA process,which deepens our understanding of how biochar mediates N cycling in the paddy field.
