研究潜艇在斜航工况下的水动力特性对潜艇操纵性的影响至关重要。本文使用雷诺平均RANS(Reynolds Average Navier-Stockes)与分离涡DES(Detached-Eddy Simulation)2种数值方法,对Joubert BB2潜艇在斜航工况下水动力性能及周围流场进行...研究潜艇在斜航工况下的水动力特性对潜艇操纵性的影响至关重要。本文使用雷诺平均RANS(Reynolds Average Navier-Stockes)与分离涡DES(Detached-Eddy Simulation)2种数值方法,对Joubert BB2潜艇在斜航工况下水动力性能及周围流场进行数值模拟。分析不同漂角工况下潜艇所受力、力矩及周围流场,重点关注围壳及尾舵附近流场,探寻漂角变化对潜艇受力及流场的影响。结果显示,采用DES方法计算大漂角工况时误差更小同时流场信息捕捉更加精确。研究结果表明,潜艇大漂角工况下采用DES方法能够更加准确地模拟潜艇受力及流场,同时对研究潜艇斜航状态下的流动分离现象具有一定的参考价值。展开更多
Long-time fermentation has always been one of the reasons restricting the development of straw biological pulping.This study aimed to develop a novel straw pulp film with shortened solid-state fermentation time with l...Long-time fermentation has always been one of the reasons restricting the development of straw biological pulping.This study aimed to develop a novel straw pulp film with shortened solid-state fermentation time with less than 20%mass loss rate by bio-pulping synergistic treatment of straw fibers with deep eutectic solvent(DES)and Streptomyces rochei(S.rochei).Results illustrated that at 3%S.rochei concentration with 7-day fermentation,both cellulose and hemicellulose enzyme activities of the treated rice straw fiber reached peak values with a fiber mass loss rate of 17.01%.Microstructural morphology revealed that S.rochei colonization initiated on straw surfaces and progressively penetrated internal structures,resulting in surface loosening and distinct disruption of cell wall tissues within vascular bundles in transverse sections.The treated rice straw strip indicated a maximum tensile strength of 46.22 MPa for(Bacteria)BA 3%at day 7,attributed to optimized synergistic effects of microfibril angle(MFA)and cellulose/hemicellulose relative content ratio.The modified straw pulp film exhibited significant enhancement in the tensile index(44.9%increase),burst index(10.3%increase),and tear index(60%increase)compared to untreated groups.This work demonstrated the important role ofDES and S.rochei bio-pulping synergistic treatment in improving rice straw pulp performance,suggesting an eco-friendly,novel,and efficient biomass pretreatment technology for potential application prospects in sustainable agricultural mulching materials.展开更多
Peste des Petits ruminants (PPR) is considered as one of the major constraints to the productivity of small ruminants in Sudan. Presently, control measures for PPR are primarily reliant on vaccination using an attenua...Peste des Petits ruminants (PPR) is considered as one of the major constraints to the productivity of small ruminants in Sudan. Presently, control measures for PPR are primarily reliant on vaccination using an attenuated PPR strain Nigeria 75/1 that has been produced in monolayers of Vero cells grown in static flasks. This study investigates the potential for scaling up PPR vaccine production using roller bottle technology, a more advanced method. A live, homologous vaccine against PPR in sheep and goats was successfully produced on a large scale in roller culture bottles, with DMEM supplemented with ten percent fetal bovine serum serving as the growth medium. The cells were infected with a multiplicity of infection of 0.01, and the vaccine was harvested when the cytopathic effect reached 80%. The vaccine was then freeze-dried to preserve its stability. A series of tests were conducted to ensure the safety and quality of the vaccine. Using PCR, the identity of vaccine was confirmed. It was found to be safe in both single and 100-times dose inoculations in sheep, with the produced batches showing a high titre of 6.4 ± 0.11 log10 TCID50/ml. All batches met the criteria of sterility, passing tests for bacteria, fungi, and mycoplasma. Furthermore, the vaccine proved effective in small ruminants, with antibodies persisting for over a year post-vaccination. The residual moisture content remained below 2.5%, and the vaccine successfully passed vacuum testing. Stability tests indicated that the vaccine has a shelf-life of at least one year when stored at temperatures of 2˚C - 8˚C and −20˚C. These results demonstrate the potential for applying roller bottle culture technology to PPR vaccine production, significantly streamlining the existing process and enhancing its efficiency. Further research is warranted to address the economic analyses of adopting roller bottle technology with existing PPR control program.展开更多
Peste des petits ruminants virus (PPRV) antibodies were studied in Sudanese sheep and goats (n = 855) before and after vaccination with a locally produced Nigeria 75/1 vaccine using a commercial competitive ELISA (cEL...Peste des petits ruminants virus (PPRV) antibodies were studied in Sudanese sheep and goats (n = 855) before and after vaccination with a locally produced Nigeria 75/1 vaccine using a commercial competitive ELISA (cELISA) kit. Animals were kept healthy under field conditions, in four states: Blue Nile (n = 250), North Kordofan (n = 189), South Darfur (n = 225) and the Northern State (n = 191). Before vaccination, the overall sero-prevalence of PPRV antibodies was 54.6% (53.2% - 56%, 95% CI);high (64.8% - 76.4%, 95% CI) in Blue Nile State, medium (50.5% - 61.9%, 95% CI) in North Kordofan State and South Darfur State and low (28.6% - 35.2% 95%, CI) in Northern State. In high-risk areas (high sero-prevalence), Blue Nile (70.4%) and North Kordofan (57.7%), middle age groups (7 - 12 and 13 - 18 months) were identified as high-risk age. Middle age groups showed lower sero-prevalence than preceding (3 - 6 months) and subsequent (>18 months) age groups while the risk of exposure increased with age. Current and previous findings suggested a transmission pathway of PPRV involving the South Eastern border (Blue Nile) and neighbouring Central Sudan to North Kordofan. One month after vaccination 88.4% (343/388) of sero-negative animals were sero-converted suggesting the efficacy of the locally produced Nigeria 75/1 vaccine. Even if only individuals in the high-risk age group (7 - 18 months) were vaccinated, the overall population immunity (OPI) in high-risk areas (the Blue Nile and North Kordofan) would have surpassed the threshold of 70%, which is indicated for blocking PPRV transmission. However, lower vaccination coverage is expected in wider vaccination programmes. These findings primarily justified the targeting of PPR control in Sudan through the vaccination of high-risk age groups in high-risk areas.展开更多
China Pavilion Opens at Expo 2025 Osaka On April 13,2025,the China Pavilion at the Expo 2025 Osaka in Japan was officially opened.The opening ceremony was attended by Chinese and foreign vips,including Ren Hongbin,C...China Pavilion Opens at Expo 2025 Osaka On April 13,2025,the China Pavilion at the Expo 2025 Osaka in Japan was officially opened.The opening ceremony was attended by Chinese and foreign vips,including Ren Hongbin,Chairman of the China Council for the Promotion of International Trade (CCPIT);Alain Berger,President of the Bureau International des Expositions (BIE);Dimitri Kerkentzes,Secretary General of the BIE.展开更多
In 2013,peste des petits ruminants(PPR)re-emerged in China and spread to the majority of provinces across the country.The disease was effectively controlled through a vaccination campaign employing live attenuated vac...In 2013,peste des petits ruminants(PPR)re-emerged in China and spread to the majority of provinces across the country.The disease was effectively controlled through a vaccination campaign employing live attenuated vaccines,although sporadic cases still occurred.However,limited information is currently available regarding the peste des petits ruminants virus(PPRV)endemic in China.Here,a PPRV strain(HLJ/13)was isolated from a field sample in China using Vero cells expressing goat signalling lymphocyte activation molecule.Phylogenetic analysis indicated that HLJ/13 belonged to lineage IV.Subsequent intranasal and subcutaneous inoculation of goats with a dose of 2×10~6 TCID50of HLJ/13 resulted in the development of typical clinical symptoms of PPR,including pyrexia,ocular and nasal discharges,stomatitis,and diarrhea.All infected goats succumbed to the disease by day 8.To gain further insight,viral loading,pathological examination and immunohistochemical analyses were conducted,elucidating the main targets of HLJ/13 as the respiratory system,digestive tract and lymphoid organs.Employing the goat infection model established above,the goat poxvirus-vectored PPR vaccine,which was previously developed and could be used as DIVA(differentiating infected from vaccinated animals)vaccine,provided complete protection against the challenge of HLJ/13.It is important to note that this study represents the first comprehensive report delineating the biology and pathogenicity characterization,and infection model of PPRV isolated in China.展开更多
文摘研究潜艇在斜航工况下的水动力特性对潜艇操纵性的影响至关重要。本文使用雷诺平均RANS(Reynolds Average Navier-Stockes)与分离涡DES(Detached-Eddy Simulation)2种数值方法,对Joubert BB2潜艇在斜航工况下水动力性能及周围流场进行数值模拟。分析不同漂角工况下潜艇所受力、力矩及周围流场,重点关注围壳及尾舵附近流场,探寻漂角变化对潜艇受力及流场的影响。结果显示,采用DES方法计算大漂角工况时误差更小同时流场信息捕捉更加精确。研究结果表明,潜艇大漂角工况下采用DES方法能够更加准确地模拟潜艇受力及流场,同时对研究潜艇斜航状态下的流动分离现象具有一定的参考价值。
基金funded by the Agricultural Science and Technology Innovation Fund of Jiangsu Province[Grant/Award Number:CX(24)1008]Key Research and Development Program Project of Henan Province(251111110100)National State Science Foundation of China[Grant/Award Number:21808093].
文摘Long-time fermentation has always been one of the reasons restricting the development of straw biological pulping.This study aimed to develop a novel straw pulp film with shortened solid-state fermentation time with less than 20%mass loss rate by bio-pulping synergistic treatment of straw fibers with deep eutectic solvent(DES)and Streptomyces rochei(S.rochei).Results illustrated that at 3%S.rochei concentration with 7-day fermentation,both cellulose and hemicellulose enzyme activities of the treated rice straw fiber reached peak values with a fiber mass loss rate of 17.01%.Microstructural morphology revealed that S.rochei colonization initiated on straw surfaces and progressively penetrated internal structures,resulting in surface loosening and distinct disruption of cell wall tissues within vascular bundles in transverse sections.The treated rice straw strip indicated a maximum tensile strength of 46.22 MPa for(Bacteria)BA 3%at day 7,attributed to optimized synergistic effects of microfibril angle(MFA)and cellulose/hemicellulose relative content ratio.The modified straw pulp film exhibited significant enhancement in the tensile index(44.9%increase),burst index(10.3%increase),and tear index(60%increase)compared to untreated groups.This work demonstrated the important role ofDES and S.rochei bio-pulping synergistic treatment in improving rice straw pulp performance,suggesting an eco-friendly,novel,and efficient biomass pretreatment technology for potential application prospects in sustainable agricultural mulching materials.
文摘Peste des Petits ruminants (PPR) is considered as one of the major constraints to the productivity of small ruminants in Sudan. Presently, control measures for PPR are primarily reliant on vaccination using an attenuated PPR strain Nigeria 75/1 that has been produced in monolayers of Vero cells grown in static flasks. This study investigates the potential for scaling up PPR vaccine production using roller bottle technology, a more advanced method. A live, homologous vaccine against PPR in sheep and goats was successfully produced on a large scale in roller culture bottles, with DMEM supplemented with ten percent fetal bovine serum serving as the growth medium. The cells were infected with a multiplicity of infection of 0.01, and the vaccine was harvested when the cytopathic effect reached 80%. The vaccine was then freeze-dried to preserve its stability. A series of tests were conducted to ensure the safety and quality of the vaccine. Using PCR, the identity of vaccine was confirmed. It was found to be safe in both single and 100-times dose inoculations in sheep, with the produced batches showing a high titre of 6.4 ± 0.11 log10 TCID50/ml. All batches met the criteria of sterility, passing tests for bacteria, fungi, and mycoplasma. Furthermore, the vaccine proved effective in small ruminants, with antibodies persisting for over a year post-vaccination. The residual moisture content remained below 2.5%, and the vaccine successfully passed vacuum testing. Stability tests indicated that the vaccine has a shelf-life of at least one year when stored at temperatures of 2˚C - 8˚C and −20˚C. These results demonstrate the potential for applying roller bottle culture technology to PPR vaccine production, significantly streamlining the existing process and enhancing its efficiency. Further research is warranted to address the economic analyses of adopting roller bottle technology with existing PPR control program.
文摘Peste des petits ruminants virus (PPRV) antibodies were studied in Sudanese sheep and goats (n = 855) before and after vaccination with a locally produced Nigeria 75/1 vaccine using a commercial competitive ELISA (cELISA) kit. Animals were kept healthy under field conditions, in four states: Blue Nile (n = 250), North Kordofan (n = 189), South Darfur (n = 225) and the Northern State (n = 191). Before vaccination, the overall sero-prevalence of PPRV antibodies was 54.6% (53.2% - 56%, 95% CI);high (64.8% - 76.4%, 95% CI) in Blue Nile State, medium (50.5% - 61.9%, 95% CI) in North Kordofan State and South Darfur State and low (28.6% - 35.2% 95%, CI) in Northern State. In high-risk areas (high sero-prevalence), Blue Nile (70.4%) and North Kordofan (57.7%), middle age groups (7 - 12 and 13 - 18 months) were identified as high-risk age. Middle age groups showed lower sero-prevalence than preceding (3 - 6 months) and subsequent (>18 months) age groups while the risk of exposure increased with age. Current and previous findings suggested a transmission pathway of PPRV involving the South Eastern border (Blue Nile) and neighbouring Central Sudan to North Kordofan. One month after vaccination 88.4% (343/388) of sero-negative animals were sero-converted suggesting the efficacy of the locally produced Nigeria 75/1 vaccine. Even if only individuals in the high-risk age group (7 - 18 months) were vaccinated, the overall population immunity (OPI) in high-risk areas (the Blue Nile and North Kordofan) would have surpassed the threshold of 70%, which is indicated for blocking PPRV transmission. However, lower vaccination coverage is expected in wider vaccination programmes. These findings primarily justified the targeting of PPR control in Sudan through the vaccination of high-risk age groups in high-risk areas.
文摘China Pavilion Opens at Expo 2025 Osaka On April 13,2025,the China Pavilion at the Expo 2025 Osaka in Japan was officially opened.The opening ceremony was attended by Chinese and foreign vips,including Ren Hongbin,Chairman of the China Council for the Promotion of International Trade (CCPIT);Alain Berger,President of the Bureau International des Expositions (BIE);Dimitri Kerkentzes,Secretary General of the BIE.
基金supported by the National Key Research and Development Program of China(2016YFD0500108)the International S&T Cooperation Program of China(ISTCP)(2015DFA31300)。
文摘In 2013,peste des petits ruminants(PPR)re-emerged in China and spread to the majority of provinces across the country.The disease was effectively controlled through a vaccination campaign employing live attenuated vaccines,although sporadic cases still occurred.However,limited information is currently available regarding the peste des petits ruminants virus(PPRV)endemic in China.Here,a PPRV strain(HLJ/13)was isolated from a field sample in China using Vero cells expressing goat signalling lymphocyte activation molecule.Phylogenetic analysis indicated that HLJ/13 belonged to lineage IV.Subsequent intranasal and subcutaneous inoculation of goats with a dose of 2×10~6 TCID50of HLJ/13 resulted in the development of typical clinical symptoms of PPR,including pyrexia,ocular and nasal discharges,stomatitis,and diarrhea.All infected goats succumbed to the disease by day 8.To gain further insight,viral loading,pathological examination and immunohistochemical analyses were conducted,elucidating the main targets of HLJ/13 as the respiratory system,digestive tract and lymphoid organs.Employing the goat infection model established above,the goat poxvirus-vectored PPR vaccine,which was previously developed and could be used as DIVA(differentiating infected from vaccinated animals)vaccine,provided complete protection against the challenge of HLJ/13.It is important to note that this study represents the first comprehensive report delineating the biology and pathogenicity characterization,and infection model of PPRV isolated in China.
