Nondestructive and noninvasive neutron assays are essential applications of neutron techniques.Neutron resonance transmission analysis(NRTA)is a powerful nondestructive method for investigating the elemental compositi...Nondestructive and noninvasive neutron assays are essential applications of neutron techniques.Neutron resonance transmission analysis(NRTA)is a powerful nondestructive method for investigating the elemental composition of an object.The back-streaming neutron line(Back-n)is a newly built time-of-flight facility at the China Spallation Neutron Source(CSNS)that provides neutrons in the eV to 300 MeV range.A feasibility study of the NRTA method for nuclide identification was conducted at the CSNS Back-n via two test experiments.The results demonstrate that it is feasible to identify different elements and isotopes in samples using the NRTA method at Back-n.This study reveals its potential future applications.展开更多
In recent years, with the constant change in the global climate, the effect of climate factors on net primary productivity(NPP) has become a hot research topic. However, two opposing views have been presented in this ...In recent years, with the constant change in the global climate, the effect of climate factors on net primary productivity(NPP) has become a hot research topic. However, two opposing views have been presented in this research area: global NPP increases with global warming, and global NPP decreases with global warming. The main reasons for these two opposite results are the tremendous differences among seasonal and annual climate variables, and the growth of plants in accordance with these climate variables. Therefore, it will fail to fully clarify the relation between vegetation growth and climate changes by research that relies solely on annual data. With seasonal climate variables, we may clarify the relation between vegetation growth and climate changes more accurately. Our research examined the arid and semiarid areas in China(ASAC), which account for one quarter of the total area of China. The ecological environment of these areas is fragile and easily affected by human activities. We analyzed the influence of climate changes, especially the changes in seasonal climate variables, on NPP, with Climatic Research Unit(CRU) climatic data and Moderate Resolution Imaging Spectroradiometer(MODIS) satellite remote data, for the years 2000–2010. The results indicate that: for annual climatic data, the percentage of the ASAC in which NPP is positively correlated with temperature is 66.11%, and 91.47% of the ASAC demonstrates a positive correlation between NPP and precipitation. Precipitation is more positively correlated with NPP than temperature in the ASAC. For seasonal climatic data, the correlation between NPP and spring temperature shows significant regional differences. Positive correlation areas are concentrated in the eastern portion of the ASAC, while the western section of the ASAC generally shows a negative correlation. However, in summer, most areas in the ASAC show a negative correlation between NPP and temperature. In autumn, precipitation is less important in the west, as opposed to the east, in which it is critically important. Temperatures in winter are a limiting factor for NPP throughout the region. The findings of this research not only underline the importance of seasonal climate variables for vegetation growth, but also suggest that the effects of seasonal climate variables on NPP should be explored further in related research in the future.展开更多
Although 18 S r DNA sequence is extremely conservative, the polymorphism still has been found in few species.In the present study, three types(Type A, B and C) of 18 S r DNA sequence coexisted in Cynoglossus lineolatu...Although 18 S r DNA sequence is extremely conservative, the polymorphism still has been found in few species.In the present study, three types(Type A, B and C) of 18 S r DNA sequence coexisted in Cynoglossus lineolatus genome, suggesting a non-concerted evolution process, rather than a strictly concerted evolution fashion.Based on the differences of sequence variation, GC content, secondary structure and minimum free energy,Types A and B were speculated as the potential pseudogenes. Additionally, a fascinating finding was a 189-bp duplication of 18 S r DNA in Type A sequence. To our knowledge, this is the first report on such a long duplication in teleostean ribosomal DNA. Compared with several theories accounting for the formation of tandem repeats, the unequal crossing over model was thought to be the most likely mechanism to generate the189-bp duplication of 18 S r DNA. These results not only provide a novel molecular evidence for the unequal crossing over model, but also benefit for the further study on 18 S r DNA in fishes.展开更多
Knowledge of complete mitochondrial genomes(mitogenomes)can help understand the molecular evolution and phylogenetic relationships of various species.To date,the phylogenetic status of Leucosiidae within Brachyura rem...Knowledge of complete mitochondrial genomes(mitogenomes)can help understand the molecular evolution and phylogenetic relationships of various species.To date,the phylogenetic status of Leucosiidae within Brachyura remains unresolved because of the limited number of mitogenomes available.In the present study,the complete mitogenome of Myra affinis was sequenced using next-generation sequencing to supplement the limited mitogenome information of Leucosiidae.The 15349 bp-long mitogenome includes 13 protein-coding genes(PCGs),22 transfer RNAs(tRNAs),2 ribosomal RNAs(rRNAs),and a putative control region.The overall base composition is 34.5%A,36.1%T,11.5%G,and 17.9%C,with a high AT bias(70.6%).All 13 PCGs start with the standard ATN codon and stop with the TAN codon or incomplete T.Except for tRNA-Ser,all other tRNAs have a typical cloverleaf-like secondary structure.Phylogenetic analyses based on the maximum likelihood and Bayesian inference methods are employed to generate identical phylogenetic topologies,thereby supporting the sister relationship between Leucosiidae and Matutidae for the first time.The monophyly of Eubrachyura is well established,and its sister relationship with Raninoida is strongly supported.The results of this work will not only help achieve a better understanding of the characteristics of the M.affinis mitogenome and the phylogenetic position of Leucosiidae,but also provide relevant information for further studies on the phylogeny of Brachyura.展开更多
Daphniopsis tibetana is widely distributed in Xinjiang,Qinghai,Tibet of China,as well as in Russia and India,which is the dominant zooplankton in many high-altitude(4000 m)salt lakes.D.tibetana can adapt to saline wat...Daphniopsis tibetana is widely distributed in Xinjiang,Qinghai,Tibet of China,as well as in Russia and India,which is the dominant zooplankton in many high-altitude(4000 m)salt lakes.D.tibetana can adapt to saline waters,whereas the other species of the superorder Cladocera can only inhabit in freshwater.However,the phylogenetic status of D.tibetana in Branchiopoda remains unclear primarily because of limited mitogenome.In this study,complete mitochondrial genome sequences of D.tibetana were sequenced and annotated for the first time to obtain a comprehensive understanding of its phylogenetic status.The complete mitogenome of D.tibetana is 16196 bp in length.It contains 37 genes,including two ribosomal RNAs(12S and 16S rRNAs)genes,22 transfer RNA(tRNA)genes,13 protein-coding genes,and one non-coding region.The overall base composition is 29.6%A,33.2%T,19.0%G,and 18.2%C with a high AT bias(62.8%).Except for trnS1(GCT),most tRNAs have a typical cloverleaf secondary structure.Phylogenetic analysis based on maximum likelihood and Bayesian inference generates identical phylogenetic topology and shows the phylogenetic status of D.tibetana,which reconfirm the distinction between the genera Daphniopsis and Daphnia.Meanwhile,the class Branchiopoda is clustered into three clades(Anostraca,Notostraca,and Diplostraca)with high support values.These results provide not only a comprehensive understanding of the characteristics of D.tibetana mitogenome and its phylogenetic position in Diplostraca,but also information for future research on the phylogeny of Branchiopoda.展开更多
Mesoporous aluminosilicate with cubic ordered structure was synthesized by two-step crystallization, which showed stronger acid sites and more effective activity for catalytic alkylation of 2, 4-ditert-butylphenol wit...Mesoporous aluminosilicate with cubic ordered structure was synthesized by two-step crystallization, which showed stronger acid sites and more effective activity for catalytic alkylation of 2, 4-ditert-butylphenol with tert-butanol than conventional H-AlMCM-48 materials.展开更多
A new structural parameter of amorphous alloys called atomic bond proportion was proposed, and a topological algorithm for the structural parameter was proven feasible in the previous work. In the present study, a cor...A new structural parameter of amorphous alloys called atomic bond proportion was proposed, and a topological algorithm for the structural parameter was proven feasible in the previous work. In the present study, a correction factor, λ,is introduced to optimize the algorithm and dramatically improve the calculation accuracy of the atomic bond proportion.The correction factor represents the ability of heterogeneous atoms to combine with one another to form the metallic bonds and it is associated with the uniformity of the master alloy, mixing enthalpy, cooling rate during preparation, and annealing time. The correction factor provides a novel pathway for researching the structures of the amorphous alloys.展开更多
Objective：The radioprotective effects of amifostine remain uncertain in patients with nasopharyngeal carcinoma（NPC）,and adverse effects and cost limit generalization of its classical everyday regimen.This phase II ...Objective：The radioprotective effects of amifostine remain uncertain in patients with nasopharyngeal carcinoma（NPC）,and adverse effects and cost limit generalization of its classical everyday regimen.This phase II multicenter randomized controlled trial aimed to explore whether amifostine could ameliorate the toxicities of NPC patients in the era of intensity-modulated radiotherapy（IMRT）,and to compare different regimens of amifostine on effectiveness and safety.Methods：Patients with stage I–IVB NPC were involved prospectively from January 1st,2013.All patients received radical treatment based on IMRT.After a randomization stratified by their stage,these patients were allocated into 3 groups：the group treated without amifostine,the group treated with the everyday regimen of amifostine,and the group treated with the every-other-day regimen.The 3 groups of patients were compared on radiotherapy-related acute toxicities,treatment effects of NPC,and amifostine-related complications.This trial was registered on the clinicaltrials.gov（ID：NCT01762514）.Results：Until August 31st,2017,totally 187 patients completed experimental intervention.Only amifostine of everyday regimen appeared to reduce the patient proportion of mucositis（79.1%vs.96.8%,P=0.002）.Hypocalcemia was less common in patients treated without amifostine than in those treated with amifostine（22.6%vs.53.4%vs.41.8%,P=0.002）.Neither complete remission rates nor the survivals were affected by amifostine.Conclusions：Amifostine of everyday regimen could reduce mucositis in NPC patients who received IMRT,though it also had the possibility to cause more hypocalcemia.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.12035017)Youth Innovation Promotion Association CAS(No.2023014)Guangdong Basic and Applied Basic Research Foundation(Nos.2020A1515010360 and 2022B1515120032).
文摘Nondestructive and noninvasive neutron assays are essential applications of neutron techniques.Neutron resonance transmission analysis(NRTA)is a powerful nondestructive method for investigating the elemental composition of an object.The back-streaming neutron line(Back-n)is a newly built time-of-flight facility at the China Spallation Neutron Source(CSNS)that provides neutrons in the eV to 300 MeV range.A feasibility study of the NRTA method for nuclide identification was conducted at the CSNS Back-n via two test experiments.The results demonstrate that it is feasible to identify different elements and isotopes in samples using the NRTA method at Back-n.This study reveals its potential future applications.
基金the Strategic Priority Research Program-Climate Change:Carbon Budget and Relevant Issues of Chinese Academy of Sciences(No.XDA05060104)
文摘In recent years, with the constant change in the global climate, the effect of climate factors on net primary productivity(NPP) has become a hot research topic. However, two opposing views have been presented in this research area: global NPP increases with global warming, and global NPP decreases with global warming. The main reasons for these two opposite results are the tremendous differences among seasonal and annual climate variables, and the growth of plants in accordance with these climate variables. Therefore, it will fail to fully clarify the relation between vegetation growth and climate changes by research that relies solely on annual data. With seasonal climate variables, we may clarify the relation between vegetation growth and climate changes more accurately. Our research examined the arid and semiarid areas in China(ASAC), which account for one quarter of the total area of China. The ecological environment of these areas is fragile and easily affected by human activities. We analyzed the influence of climate changes, especially the changes in seasonal climate variables, on NPP, with Climatic Research Unit(CRU) climatic data and Moderate Resolution Imaging Spectroradiometer(MODIS) satellite remote data, for the years 2000–2010. The results indicate that: for annual climatic data, the percentage of the ASAC in which NPP is positively correlated with temperature is 66.11%, and 91.47% of the ASAC demonstrates a positive correlation between NPP and precipitation. Precipitation is more positively correlated with NPP than temperature in the ASAC. For seasonal climatic data, the correlation between NPP and spring temperature shows significant regional differences. Positive correlation areas are concentrated in the eastern portion of the ASAC, while the western section of the ASAC generally shows a negative correlation. However, in summer, most areas in the ASAC show a negative correlation between NPP and temperature. In autumn, precipitation is less important in the west, as opposed to the east, in which it is critically important. Temperatures in winter are a limiting factor for NPP throughout the region. The findings of this research not only underline the importance of seasonal climate variables for vegetation growth, but also suggest that the effects of seasonal climate variables on NPP should be explored further in related research in the future.
基金The National Natural Science Foundation of China under contract No.31272273the Open Research Fund Program of Guangxi Key Laboratory of Mangrove Conservation and Utilization under contract No.GKLMC-201502
文摘Although 18 S r DNA sequence is extremely conservative, the polymorphism still has been found in few species.In the present study, three types(Type A, B and C) of 18 S r DNA sequence coexisted in Cynoglossus lineolatus genome, suggesting a non-concerted evolution process, rather than a strictly concerted evolution fashion.Based on the differences of sequence variation, GC content, secondary structure and minimum free energy,Types A and B were speculated as the potential pseudogenes. Additionally, a fascinating finding was a 189-bp duplication of 18 S r DNA in Type A sequence. To our knowledge, this is the first report on such a long duplication in teleostean ribosomal DNA. Compared with several theories accounting for the formation of tandem repeats, the unequal crossing over model was thought to be the most likely mechanism to generate the189-bp duplication of 18 S r DNA. These results not only provide a novel molecular evidence for the unequal crossing over model, but also benefit for the further study on 18 S r DNA in fishes.
基金supported by the Natural Science Foundation of Zhejiang Province (No. LY21C190007)the Zhoushan Science and Technology Bureau (No. 2021C21 007)
文摘Knowledge of complete mitochondrial genomes(mitogenomes)can help understand the molecular evolution and phylogenetic relationships of various species.To date,the phylogenetic status of Leucosiidae within Brachyura remains unresolved because of the limited number of mitogenomes available.In the present study,the complete mitogenome of Myra affinis was sequenced using next-generation sequencing to supplement the limited mitogenome information of Leucosiidae.The 15349 bp-long mitogenome includes 13 protein-coding genes(PCGs),22 transfer RNAs(tRNAs),2 ribosomal RNAs(rRNAs),and a putative control region.The overall base composition is 34.5%A,36.1%T,11.5%G,and 17.9%C,with a high AT bias(70.6%).All 13 PCGs start with the standard ATN codon and stop with the TAN codon or incomplete T.Except for tRNA-Ser,all other tRNAs have a typical cloverleaf-like secondary structure.Phylogenetic analyses based on the maximum likelihood and Bayesian inference methods are employed to generate identical phylogenetic topologies,thereby supporting the sister relationship between Leucosiidae and Matutidae for the first time.The monophyly of Eubrachyura is well established,and its sister relationship with Raninoida is strongly supported.The results of this work will not only help achieve a better understanding of the characteristics of the M.affinis mitogenome and the phylogenetic position of Leucosiidae,but also provide relevant information for further studies on the phylogeny of Brachyura.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(Nos.LY22D060001,LY20C190008)the National Natural Science Foundation of China(Nos.41806156,31702321)+3 种基金the Fund of Guangdong Provincial Key Laboratory of Fishery Ecology and Environment(FEEL-2021-8)the Open Foundation from Key Laboratory of Tropical Marine Bio-resources and Ecology,Chinese Academy of Sciences(No.LMB20201005)the Science and Technology Project of Zhoushan(No.2020 C21016),the Open Foundation from Marine Sciences in the First-Class Subjects of Zhejiang(Nos.20200201,20200202)the Starting Research Fund from the Zhejiang Ocean University.
文摘Daphniopsis tibetana is widely distributed in Xinjiang,Qinghai,Tibet of China,as well as in Russia and India,which is the dominant zooplankton in many high-altitude(4000 m)salt lakes.D.tibetana can adapt to saline waters,whereas the other species of the superorder Cladocera can only inhabit in freshwater.However,the phylogenetic status of D.tibetana in Branchiopoda remains unclear primarily because of limited mitogenome.In this study,complete mitochondrial genome sequences of D.tibetana were sequenced and annotated for the first time to obtain a comprehensive understanding of its phylogenetic status.The complete mitogenome of D.tibetana is 16196 bp in length.It contains 37 genes,including two ribosomal RNAs(12S and 16S rRNAs)genes,22 transfer RNA(tRNA)genes,13 protein-coding genes,and one non-coding region.The overall base composition is 29.6%A,33.2%T,19.0%G,and 18.2%C with a high AT bias(62.8%).Except for trnS1(GCT),most tRNAs have a typical cloverleaf secondary structure.Phylogenetic analysis based on maximum likelihood and Bayesian inference generates identical phylogenetic topology and shows the phylogenetic status of D.tibetana,which reconfirm the distinction between the genera Daphniopsis and Daphnia.Meanwhile,the class Branchiopoda is clustered into three clades(Anostraca,Notostraca,and Diplostraca)with high support values.These results provide not only a comprehensive understanding of the characteristics of D.tibetana mitogenome and its phylogenetic position in Diplostraca,but also information for future research on the phylogeny of Branchiopoda.
基金We thank financial support by the National Natural Science Foundation of China(grant 29973001).
文摘Mesoporous aluminosilicate with cubic ordered structure was synthesized by two-step crystallization, which showed stronger acid sites and more effective activity for catalytic alkylation of 2, 4-ditert-butylphenol with tert-butanol than conventional H-AlMCM-48 materials.
基金Project supported by Excellent Youth Foundation of Jiangsu Scientific Committee,China(Grant No.BK20180106)the National Natural Science Foundation of China(Grant No.51804091)+1 种基金Industry-University-Research Cooperation Project of Jiangsu Province,China(Grant No.BY2020383)Opening Project of State Key Laboratory of Metastable Materials Science and Technology(Grant No.201910).
文摘A new structural parameter of amorphous alloys called atomic bond proportion was proposed, and a topological algorithm for the structural parameter was proven feasible in the previous work. In the present study, a correction factor, λ,is introduced to optimize the algorithm and dramatically improve the calculation accuracy of the atomic bond proportion.The correction factor represents the ability of heterogeneous atoms to combine with one another to form the metallic bonds and it is associated with the uniformity of the master alloy, mixing enthalpy, cooling rate during preparation, and annealing time. The correction factor provides a novel pathway for researching the structures of the amorphous alloys.
基金supported by the grants of the Hi-Tech Research and Development Program of China (Grant No.2006AA02Z4B4)the National Key Projects of Research and Development of China (Grant No.2016YFC0904600)
文摘Objective：The radioprotective effects of amifostine remain uncertain in patients with nasopharyngeal carcinoma（NPC）,and adverse effects and cost limit generalization of its classical everyday regimen.This phase II multicenter randomized controlled trial aimed to explore whether amifostine could ameliorate the toxicities of NPC patients in the era of intensity-modulated radiotherapy（IMRT）,and to compare different regimens of amifostine on effectiveness and safety.Methods：Patients with stage I–IVB NPC were involved prospectively from January 1st,2013.All patients received radical treatment based on IMRT.After a randomization stratified by their stage,these patients were allocated into 3 groups：the group treated without amifostine,the group treated with the everyday regimen of amifostine,and the group treated with the every-other-day regimen.The 3 groups of patients were compared on radiotherapy-related acute toxicities,treatment effects of NPC,and amifostine-related complications.This trial was registered on the clinicaltrials.gov（ID：NCT01762514）.Results：Until August 31st,2017,totally 187 patients completed experimental intervention.Only amifostine of everyday regimen appeared to reduce the patient proportion of mucositis（79.1%vs.96.8%,P=0.002）.Hypocalcemia was less common in patients treated without amifostine than in those treated with amifostine（22.6%vs.53.4%vs.41.8%,P=0.002）.Neither complete remission rates nor the survivals were affected by amifostine.Conclusions：Amifostine of everyday regimen could reduce mucositis in NPC patients who received IMRT,though it also had the possibility to cause more hypocalcemia.
