期刊文献+
共找到30篇文章
< 1 2 >
每页显示 20 50 100
Correction to:Molecular characterization and functional analysis of daf-8 in the pinewood nematode,Bursaphelenchus xylophilus
1
作者 Jinghan Wang Huan Hong +7 位作者 Rong Xie Jingjing Ji Kai Guo Liqun Bai jia tang Hongshi Yu jianren Ye jiafu Hu 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第5期1651-1651,共1页
Correction to:J.For.Res.(2022)33:689–698 https://doi.org/10.1007/s11676-021-01335-7 In the Original Publication,the text“Acknowledgements sdfkjds”has been inadvertently appeared in the paper.The Original article ha... Correction to:J.For.Res.(2022)33:689–698 https://doi.org/10.1007/s11676-021-01335-7 In the Original Publication,the text“Acknowledgements sdfkjds”has been inadvertently appeared in the paper.The Original article has been corrected. 展开更多
关键词 KNOWLEDGE characterization FUNCTIONAL
下载PDF
Pt_(x)Cu_(y)/C电催化剂甲醇氧化反应性能及机理研究 被引量:2
2
作者 唐佳 张晓明 +2 位作者 于陕升 王素力 孙公权 《电化学》 CAS CSCD 北大核心 2021年第5期508-517,共10页
直接甲醇燃料电池(DMFC)是一种将甲醇燃料的化学能直接转化为电能的能量转换装置,具有能量转化效率高、环境友好、燃料来源丰富等优势,在移动电源等领域具有广泛应用前景,但阳极铂基电催化剂的性能及成本制约着DMFC的发展。本论文通过... 直接甲醇燃料电池(DMFC)是一种将甲醇燃料的化学能直接转化为电能的能量转换装置,具有能量转化效率高、环境友好、燃料来源丰富等优势,在移动电源等领域具有广泛应用前景,但阳极铂基电催化剂的性能及成本制约着DMFC的发展。本论文通过简单的液相浸渍还原法,制备了系列PtCu/C纳米电催化剂,电化学性能测试结果表明,电催化剂对甲醇氧化反应(MOR)活性顺序为商品Pt/C<Pt_(3)Cu/C<PtCu_(4)/C<PtCu/C<PtCu_(3)/C,且活性最高的PtCu_(3)/C电催化剂表现出较为优异的电化学稳定性。结合物相表征、电化学测试及DFT计算,阐释了PtCu_(3)/C催化剂中存在的少量CuO相能够促进水分子解离产生*OH,通过双功能机制促进类CO反应中间物种氧化为CO_(2)。因此,相比于商品Pt/C,虽然PtCu_(3)/C电催化剂的ECSA不足其一半,但质量比活性和面积比活性分别提高1.88倍和3.74倍。 展开更多
关键词 Pt_(x)Cu_(y)/C电催化剂 甲醇氧化反应 CuO相
下载PDF
基于磁共振成像乳腺癌远处转移预测模型的研究 被引量:6
3
作者 汤加 马文娟 +2 位作者 刘君君 邵真真 刘佩芳 《中国肿瘤临床》 CAS CSCD 北大核心 2019年第7期337-341,共5页
目的:建立基于平扫磁共振成像(magnetic resonance imaging,MRI)和动态对比增强(dynamic contrast enhanced,DCE)-MRI影像特征参数的乳腺癌远处转移预测模型。方法:回顾性分析2011年1月至2016年12月3 032例于天津医科大学肿瘤医院行乳腺... 目的:建立基于平扫磁共振成像(magnetic resonance imaging,MRI)和动态对比增强(dynamic contrast enhanced,DCE)-MRI影像特征参数的乳腺癌远处转移预测模型。方法:回顾性分析2011年1月至2016年12月3 032例于天津医科大学肿瘤医院行乳腺MRI检查并经病理证实为乳腺浸润性癌患者的临床资料,根据纳入标准筛选出转移组93例和非转移组186例。分析转移组远处转移部位与分子分型的关系,同时对两组MRI影像特征进行单因素分析及多因素Logistics回归分析,获得独立预测因子并建立预测模型。结果:转移组中Luminal型、HER-2过表达型、三阴性乳腺癌最常见远处转移部位分别为骨、肝脏、肺脏。单因素分析结果显示,两组间的病变类型、是否多发、T1WI和T2WI信号均匀度及病灶最大径进行比较差异具有统计学意义(P<0.05)。多因素Logistics回归分析结果显示,病变类型、是否多发、T2WI信号均匀度及病灶最大径为独立预测因子。根据独立预测因子建立的预测模型准确率、敏感度、特异度和受试者工作特征曲线(receiver operating characteristic,ROC)下面积(area under receiver operating characteristic curve,AUC)分别为82.8%、85.7%、75.0%和0.801。结论:基于MRI影像特征的模型对预测乳腺癌远处转移具有潜在价值。 展开更多
关键词 乳腺癌 肿瘤转移 磁共振成像 预测 分子分型
下载PDF
A Risk Score System for Myopia Symptom Warning 被引量:4
4
作者 Dan-dan DU Wen-long XU +7 位作者 Li-hua YANG He-xin WANG Chang-mei GU jia tang Fang LI Ting XU Shi-qing WU Mei-xia LU 《Current Medical Science》 SCIE CAS 2019年第3期455-462,共8页
Myopia is the leading cause of visual impairments worldwide. Some studies revealed that visual experience in early life affected the final myopia, indicating that environmental factors play an impellent role in the de... Myopia is the leading cause of visual impairments worldwide. Some studies revealed that visual experience in early life affected the final myopia, indicating that environmental factors play an impellent role in the development of myopia. However, risk factors of myopia are still not identified among adolescents in China. A total of 4104 cases of myopia symptom and 3306 emmetropia controls were selected from students in primary and middle schools in Wuhan in 2008. We identified the risk factors associated with myopia symptom by multivariate logistic regression in this cross-sectional study and constructed a risk score system for myopia symptom. The value of the area under the receiver operating characteristic curve (ROC) was 0.735. Furthermore, we followed up 93 students aged 7-9 years for one year and calculated the total points using the score system. We found no significant difference between the final myopia symptom and the results predicted by the total points by pair chi-square test (P>0.05). The score system had a modest ability to estimate the risk factors of myopia symptom. Using this score system, we could identify the students who are at risk of myopia symptom in the future according to their behaviors and environmental factors, and take measures to slow the progress of myopia symptom. 展开更多
关键词 MYOPIA SYMPTOM adolescents RISK SCORE SYSTEM
下载PDF
Selective recovery of Cu(Ⅱ) through polymer inclusion membranes mediated with 2-aminomethylpyridine derivatives 被引量:2
5
作者 Xue-jing QIU jia tang +3 位作者 Jun TAN Hui-ping HU Xiao-bo JI Jiu-gang HU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第11期3591-3601,共11页
The Cu(Ⅱ) separation behaviors with polymer inclusion membranes(PIMs) are explored by modifying 2-aminomethylpyridine derivatives with hydrophobic alkyl chains, including 2-[N-(tert-butyloxycarbonylmethyl)-2-picolyam... The Cu(Ⅱ) separation behaviors with polymer inclusion membranes(PIMs) are explored by modifying 2-aminomethylpyridine derivatives with hydrophobic alkyl chains, including 2-[N-(tert-butyloxycarbonylmethyl)-2-picolyamino]acetate(AMB), N,N-dioctyl-2-aminomethylpyridine(AMD), tert-butyl 2-(N-octyl-2-picolyamino) acetate(AMC), and N,N-didecyl-2-aminomethylpyridine(AME). The transport flux and selectivity of Cu(Ⅱ) are determined by optimizing composition and structure of carriers and plasticizers. The results show that the hydrophobic modification of 2-aminomethylpyridine derivatives can boost the selective transport of copper ions in PIMs and membrane stability. In the optimum composition of 30 wt.% PVC, 30 wt.% AME, and 40 wt.% NPOE, the initial flux of Cu(Ⅱ) is 5.8×10^(−6) mol·m^(−2)·s^(−1). The FT-IR and XPS spectra identify that the alkyl amine functional groups of AME involve in the transport of copper chloride species. The SAXS analysis demonstrates that the generated micro-channels in PIMs induced by the hydrophobic modification of 2-aminomethylpyridine derivatives can contribute to the enhanced Cu(Ⅱ) flux. 展开更多
关键词 hydrophobic modification 2-aminomethylpyridine derivative polymer inclusion membrane Cu(Ⅱ) separation
下载PDF
二甲双胍对偏头痛大鼠模型NALP3表达的影响
6
作者 贾塘 欧阳颖 +1 位作者 母发光 何海兰 《实用医院临床杂志》 2020年第3期4-7,共4页
目的探讨在二甲双胍的干预下硝酸甘油偏头痛大鼠模型中NALP3炎性小体及其上游分子嘌呤离子型受体P2X的第7亚型(P2X7受体)的表达情况。方法将48只SD雄性大鼠随机分为空白组(A)、模型组(B)、二甲双胍干预组(C)及经典氟桂利嗪组(D)。采用Ta... 目的探讨在二甲双胍的干预下硝酸甘油偏头痛大鼠模型中NALP3炎性小体及其上游分子嘌呤离子型受体P2X的第7亚型(P2X7受体)的表达情况。方法将48只SD雄性大鼠随机分为空白组(A)、模型组(B)、二甲双胍干预组(C)及经典氟桂利嗪组(D)。采用Tassorelli法制作慢性偏头痛大鼠模型,观察注射硝酸甘油后大鼠行为学表现,进行行为学评分判断造模是否成功,并观察大鼠在药物干预后的行为学变化,留取造模成功的三叉神经节组织,运用免疫组化检测P2X7受体、Western blot检测NALP3炎性小体表达情况。结果行为学结果显示,经二甲双胍干预后大鼠行为学评分较模型组评分降低,差异有统计学意义(P<0.05)。免疫组化及Western blot测定结果显示P2X7受体及NALP3蛋白表达较模型组减少,差异有统计学意义(P<0.05)。结论在偏头痛发病机制中P2X7受体及NALP3的表达可能存在正相关;二甲双胍减少P2X7受体及NALP3的表达可能是治疗偏头痛的机制之一。 展开更多
关键词 偏头痛 二甲双胍 P2X7受体 NALP3
下载PDF
Molecular characterization and functional analysis of daf-8 in the pinewood nematode,Bursaphelenchus xylophilus 被引量:1
7
作者 Jinghan Wang Huan Hong +7 位作者 Rong Xie Jingjing Ji Kai Guo Liqun Bai jia tang Hongshi Yu jianren Ye jiafu Hu 《Journal of Forestry Research》 SCIE CAS CSCD 2022年第2期689-698,共10页
Bursaphelenchus xylophilus,causal agent of pine wilt disease,causes extensive damage worldwide.Strate-gies are needed to inhibit population growth or block the spread of the invasive nematode to control pine wilt dis-... Bursaphelenchus xylophilus,causal agent of pine wilt disease,causes extensive damage worldwide.Strate-gies are needed to inhibit population growth or block the spread of the invasive nematode to control pine wilt dis-ease.The gene daf-8 plays crucial roles in larval develop-ment and dauer formation in Caenorhabditis elegans,but little is known about its orthologue in B.xylophilus.In the present molecular characterization and functional analysis of daf-8 in B.xylophilus(Bx-daf-8),RT-qPCR showed that the expression of Bx-daf-8 gradually increased during the embryonic stage,peaked in the second-stage juvenile(J2),then dramatically dropped in the J3,and remained at that low level for the rest of its life.Bx-daf-8-transgenic C.elegans was employed to mimic the spatiotemporal expression of Bx-daf-8,which was expressed close to the pharynx during early embryogenesis and weakly throughout the whole body during late embryogenesis.It was observed in head neurons and tail ganglions throughout all postembryonic stages.B.xylophilus embryos were severely abnormal,and hatching rate decreased sharply after Bx-daf-8 knockdown.daf-16-1 and da-f16-2,downstream genes in the IIS pathway,also dropped sharply after Bx-daf-8 knockdown.We propose that TGFβmay crosstalk with the IIS pathway upstream of Bx-daf-16 and that daf-8 may act as a master regulator of daf-16 in B.xylophilus.However,knockdown of Bx-daf-8 did not lead to constitutive developmental arrest at the dauer larval stage,indicating that dauer entry in B.xylophilus might be controlled by several genes and is more complicated than in C.elegans.Bx-daf-8 alone did not control the dauer entry in B.xylophilus,but it was indispensable for embryogen-esis,providing a potential target for suppressing population growth of B.xylophilus. 展开更多
关键词 Daf-8 Expression pattern RNAI EMBRYOGENESIS Bursaphelenchus xylophilus
下载PDF
Application of Ecological Footprint 被引量:1
8
作者 jia tang Zhilan CHEN jiangping FANG 《Asian Agricultural Research》 2017年第3期57-60,63,共5页
Ecological footprint is a method of measuring how much we use the natural resources and how much the nature provides services for human beings. This paper summarized the application of ecological footprint at differen... Ecological footprint is a method of measuring how much we use the natural resources and how much the nature provides services for human beings. This paper summarized the application of ecological footprint at different scales and in different fields and different ecological types at home and abroad,analyzed the advantages and disadvantages of ecological footprint method,and made a prediction of the application of ecological footprint. 展开更多
关键词 Ecological footprint Natural resources Ecological deficit Sustainable development
下载PDF
Involvement of the ammonium assimilation mediated by glutamate dehydrogenase in response to heat stress in the scleractinian coral Pocillopora damicornis
9
作者 jia tang Wenqi CAI +3 位作者 Zhicong YAN Zhongjie WU Qianxi YANG Zhi ZHOU 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2022年第5期2001-2011,共11页
Glutamate dehydrogenase(GDH)plays an important role in the ammonium assimilation and nitrogen metabolism by catalyzing the reversible oxidative deamination of L-glutamate toα-ketoglutarate.In the present study,the po... Glutamate dehydrogenase(GDH)plays an important role in the ammonium assimilation and nitrogen metabolism by catalyzing the reversible oxidative deamination of L-glutamate toα-ketoglutarate.In the present study,the potential functions of GDH in response to heat stre ss were explored in the scleractinian coral Pocillopora damicornis(designated as PdGDH).The cDNA of PdGDH contained an open reading frame of 1611 bp encoding a polypeptide of 536 amino acids,which exhibited the highest sequence identity to GDH of Stylophora pistillata(96%identity),and the deduced PdGDH protein was predicted to contain one GdhA domain(from Val95 to Tyr525).The recombinant protein of PdGDH(rPdGDH)was expressed in Escherichia coli BL21(DE3)-Transetta,and its catalytic activity was measured under different temperatures,pH conditions and epigallocatechin-3-gallate(EGCG,a GDH inhibitor)concentrations.The purified rPdGDH only used reduced coenzyme nicotinamide adenine dinucleotide(NADH)as coenzyme,and its highe st activity was observed at 35℃and pH 7.5,re spectively.The rPdGDH activity was negatively correlated with the concentration of EGCG,and was inhibited by more than half(65%,P<0.05)at 10mol/L EGCG.No significant alteration of PdGDH mRNA expression was detected at 12 h after exposure to heat and ammonium(P>0.05).Furthermore,the activities of NADH-GDH in the scleractinian coral P.damicornis increased significantly at 12 h after the heat and ammonium stress,and the NADH-GDH activity in the heat stress group(32.66 U/mg,P<0.05)was significantly higher than that in the heat and ammonium stress group(11.26 U/mg).These results collectively suggested that PdGDH,as a homologue of glutamate dehydrogenase in the scleractinian coral P.damicornis,could respond to heat stress at the protein level,which would have ability to further promote ammonium assimilation to increase the heat acclimatization of the coral-Symbiodiniaceae symbiotic association. 展开更多
关键词 scleractinian coral glutamate dehydrogenase ammonium assimilation global warming heat response
下载PDF
The QseB/QseC two-component system contributes to virulence of Actinobacillus pleuropneumoniae by downregulating apf gene cluster transcription
10
作者 Benzhen Duan Wei Peng +6 位作者 Kang Yan Feng Liu jia tang Feng ming Yang Huanchun Chen Fangyan Yuan Weicheng Bei 《Animal Diseases》 2022年第1期33-44,共12页
Actinobacillus pleuropneumoniae(APP)is the major pathogen of porcine contagious pleuropneumoniae(PCP).The QseB/QseC two-component system(TCS)consists of the regulator QseB and the kinase QseC,which relates to quorum s... Actinobacillus pleuropneumoniae(APP)is the major pathogen of porcine contagious pleuropneumoniae(PCP).The QseB/QseC two-component system(TCS)consists of the regulator QseB and the kinase QseC,which relates to quorum sensing(QS)and virulence in some bacteria.Here,we investigated the role of QseB/QseC in apf gene cluster(apfABCD)expression of APP.Our results have showed that QseB/QseC TCS can potentially regulate the expression of apf gene cluster.The△qseBC,△apfA,△apfB,△apfC and△apfD strains are more sensitive to acidic and osmotic stressful conditions,and exhibite lower biofilm formation ability than wild-type(WT)strain,whereas the complemented strains show similar phenotype to the wr strain.In additon,the mutants have defective antiphagocytosis,adhesion and invasion when they come into contact with the host cells.In experimental animal models of infection,mice infected with△qseBC,△apfA,△apfB,△apfC and △apfD strains showed lower mortality and bacterial loads in the lung and the blood than those infected with wr strain.In conclusion,our results suggest that QseB/QseC TCS contributes to stress resistance,biofilm formation,phagocytosis,adhesion,invasion and virulence by downregulating expression of apf gene cluster in A.pleuropneumoniae. 展开更多
关键词 A.pleuropneumoniae QseB/QseC Transcriptional regulation apf gene cluster VIRULENCE
下载PDF
Estimation of Biodiversity Conservation Value of Forest Ecosystem in Nyingchi Prefecture of Tibet
11
作者 jia tang Zhilan CHEN jiangping FANG 《Asian Agricultural Research》 2017年第2期62-65,共4页
The estimation was made for the conservation value of forest ecosystem biodiversity in Nyingchi Prefecture of Tibet.The results showed that the annual economic benefits of biodiversity in Nyingchi Prefecture were abou... The estimation was made for the conservation value of forest ecosystem biodiversity in Nyingchi Prefecture of Tibet.The results showed that the annual economic benefits of biodiversity in Nyingchi Prefecture were about 21.4 billion yuan,and the annual economic benefits of global biodiversity were about 3 trillion USD.It indicated that the ecological value of forest ecosystem in Nyingchi Prefecture is high,forest ecosystem has extremely important ecological value.Therefore,in the decision-making process,it is necessary to strengthen the protection of forest ecosystem,with particular emphasis on the restoration of damaged ecosystem. 展开更多
关键词 BIODIVERSITY Value estimation Forest ecosystem Nyingchi Prefecture
下载PDF
Study on the Growth Adaptability of Ligustrum L. Plants in Southeast Tibet
12
作者 jia tang Zhilan CHEN jiangping FANG 《Asian Agricultural Research》 2017年第8期38-39,共2页
In this study,we choose the street green space in Bayi District,Mainling Town of Mainling County and Zhamu Town of Bomê County in Nyingchi City as investigation sites.In each investigation site,we select the unda... In this study,we choose the street green space in Bayi District,Mainling Town of Mainling County and Zhamu Town of Bomê County in Nyingchi City as investigation sites.In each investigation site,we select the undamaged plant communities of moderate density as objects of investigation and record,and establish the investigation database.Based on the habitat records and natural ecological conditions,we analyze the growth adaptability of Ligustrum L.plants in Southeast Tibet and the key influencing factors.It is found that the Ligustrum L.plants introduced in Southeast Tibet mainly include Ligustrum lucidum Ait.,Ligustrum quihoui Carr.and Ligustrum vicaryi.The growth adaptability of Ligustrum lucidum Ait.plants is divided into high level,middle level and low level.According to the investigation results,the frequency of Ligustrum lucidum Ait.plants with good growth status is greater than 65%.In general,the plants are fond of light,and have certain tolerance to cold.They can be cultivated in open field and show good growth adaptability in Southeast Tibet,so these plants can be further applied. 展开更多
关键词 Ligustrum lucidum Ait. Growth adaptability Urban greening
下载PDF
萘基全噻吩双螺旋体的合成与光物理行为研究
13
作者 徐婉 李冰冰 +3 位作者 秋帅 汤佳 徐莉 王华 《中国科学:化学》 CAS CSCD 北大核心 2024年第8期1361-1368,共8页
以“马鞍型”环八四噻吩(COTh)构筑的双螺旋体DH-1为母体化合物,通过Negishi偶联反应制备了双α-萘基与双β-萘基双螺旋体化合物DH-Np-1和DH-Np-2.DH-Np-1和DH-Np-2的晶体结构表明萘基取代位置不同导致分子平面性的显著差异,其中α-萘... 以“马鞍型”环八四噻吩(COTh)构筑的双螺旋体DH-1为母体化合物,通过Negishi偶联反应制备了双α-萘基与双β-萘基双螺旋体化合物DH-Np-1和DH-Np-2.DH-Np-1和DH-Np-2的晶体结构表明萘基取代位置不同导致分子平面性的显著差异,其中α-萘基、β-萘基与相连的噻吩环的平均二面角分别为73.6°与36.8°,展示出不同的共轭效应,并表现出其吸收和荧光光谱行为存在显著的差异.通过高效液相色谱法对DH-Np-1进行了手性拆分,其对映体(+)-DH-Np-1和(-)-DH-Np-1具有显著的圆二色性与圆偏振发光性质,发光不对称因子达4.9×10^(-3).旋光体(-)-DH-Np-1在固态下250℃加热18 h与在1,2-二氯苯溶液中200℃加热10 h的条件下均未发生外消旋化,表现出较高的旋光稳定性. 展开更多
关键词 环八四噻吩 双螺旋体 晶体结构 手性 圆偏振发光
原文传递
Ecological sustainability assessment of the carbon footprint in Fujian Province,southeast China 被引量:1
14
作者 Jingyu ZENG Rongrong ZHANG +7 位作者 jia tang Jingchen LIANG Jinghan LI Yue ZENG Yefan LI Qing ZHANG Wei SHUI Qianfeng WANG 《Frontiers of Earth Science》 SCIE CAS CSCD 2021年第1期12-22,共11页
China’s rapid economic development has initiated the deterioration of its ecological environment,posing a threat to the sustainable development of human society.As a result,an assessment of regional sustainability is... China’s rapid economic development has initiated the deterioration of its ecological environment,posing a threat to the sustainable development of human society.As a result,an assessment of regional sustainability is critical.This paper researches China’s most forested province,Fujian Province,as the study area.We proposed a grid-based approach to assess the regional carbon footprint in accordance with the Intergovernmental Panel on Climate Change’s(IPCC)carbon emission guidelines.Our method of assessment also introduced carbon emission indicators with our improved and published Net Primary Production(NPP)based on process simulation.The carbon footprint in Fujian Province from 2005-2017 was calculated and examined from a spatiotemporal perspective.Ecological indicators were used in the sustainability assessment.The research draws the following conclusions:1)the carbon footprint in the eastern regions of Fujian Province was higher due to rapid economic development;2)that of the western regions was lower;3)an uptrend in the carbon footprint of Fujian Province was observed.All five ecological indicators based on carbon emissions and economic and social data showed an ecologically unsustainable trend over 13 years in the research area due to unsustainable economic development.Therefore,it is urgent to balance the relationship between economic development and environmental protection.Our research provides scientific references for achieving ecological civilization and sustainability in a similar region. 展开更多
关键词 Fujian Province carbon emission carbon footprint ecological index sustainable development
原文传递
Enhancement of extracellular Cr(Ⅵ) reduction for anammox recovery using hydrazine: performance, pathways, and mechanism
15
作者 Caiyan Qu Lushan Li +8 位作者 Fan Feng Kainian jiang Xing Wu Muchuan Qin jia tang Xi tang Ruiyang Xiao Di Wu Chongjian tang 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2023年第9期233-243,共11页
The hexavalent chromium(Cr(Ⅵ))would frequently impose inhibition to anaerobic ammonium oxidation(anammox)process,hindering the efficiency of nitrogen removal in wastewater treatment.Hydrazine(N2H4),which is an interm... The hexavalent chromium(Cr(Ⅵ))would frequently impose inhibition to anaerobic ammonium oxidation(anammox)process,hindering the efficiency of nitrogen removal in wastewater treatment.Hydrazine(N2H4),which is an intermediate product of anammox,participates in intracellular metabolism and extracellular Cr(Ⅵ)reduction.However,the roles of N_(2)H_(4)-induced intracellular metabolism and extracellular reduction in nitrogen removal under Cr(Ⅵ)stress remain unclear.The addition of 3.67 mg/L of N2H4 increased the anammox activity by 17%.As an intermediate,N2H4 enhanced anammox metabolism by increasing the heme c content and electron transfer system activity.As a reductant,N_(2)H_(4) accelerated the reduction of c-Cyts-mediated extracellular Cr(Ⅵ)to the less toxic Cr(Ⅲ).Extracellular Cr(Ⅲ)accounts for 74%of the total Cr in a Cr(Ⅵ)-stressed anammox consortia.These findings highlight that N_(2)H_(4)-induced extracellular Cr(Ⅵ)reduction is the dominant mechanism for the survival of anammox consortia.We also found that N_(2)H_(4) increased the production of extracellular polymeric substances to sequester excessive Cr(Ⅵ)and produced Cr(Ⅲ).Taken together,the study findings suggest a potential strategy for enhancing nitrogen removal from ammonium-rich wastewater contaminated with Cr(Ⅵ). 展开更多
关键词 Extracellular Cr(VI)reduction Electron transfer ANAMMOX HYDRAZINE Cr(VI)inhibition
原文传递
神经科学家利用蝙蝠寻求解开大脑三维空间导航的秘密 被引量:3
16
作者 付子英 唐佳 陈其才 《科学通报》 EI CAS CSCD 北大核心 2020年第8期656-664,共9页
揭开人和动物大脑方位感知与空间导航的秘密,一直是一个令人着迷的问题.科学家通过对大鼠和蝙蝠等动物近50年的研究,使我们对大脑二维(2 dimension, 2D)导航的神经基础有了较清楚的认识.研究发现,在海马和内嗅皮质等脑区有专门的导航细... 揭开人和动物大脑方位感知与空间导航的秘密,一直是一个令人着迷的问题.科学家通过对大鼠和蝙蝠等动物近50年的研究,使我们对大脑二维(2 dimension, 2D)导航的神经基础有了较清楚的认识.研究发现,在海马和内嗅皮质等脑区有专门的导航细胞,包括位置细胞、网格细胞、边界细胞、头朝向细胞等.这些细胞及它们的"细胞域"可为2D空间导航提供"空间认知地图"或"心灵环境地图"和"指南针".然而,人和大量动物都生活在三维(3 dimension, 3D)空间中,大脑如何完成3D空间环境下的定位和导航?近年来,通过对爬行和飞行状态蝙蝠的研究,发现参与2D导航的那些细胞在3D空间下反应特性和模式均发生明显变化;蝙蝠属于社会性和群居性动物,研究还发现在其海马内存在社交位置细胞和目标方向角调谐细胞,分别负责获取环境中其他蝙蝠位置的踪迹信息以及目标的方向信息.由此可见,脑内这些空间定位细胞构成了导航的神经基础,并经过复杂的功能整合,构成了一个位于脑内的"微型全球定位系统",且在细胞水平上阐释了这种高级认知功能的原理.本文简要介绍了Nachum Ulanovsky等人近些年对蝙蝠大脑3D导航的研究. 展开更多
关键词 三维导航 位置细胞 网格细胞 头方位细胞 边界细胞 蝙蝠
原文传递
表面等离激元增强硅基近红外光电导探测器 被引量:3
17
作者 唐恝 李家祥 +1 位作者 陈沁 文龙 《中国激光》 EI CAS CSCD 北大核心 2020年第11期309-316,共8页
近年来,表面等离激元(SP)增强的金属纳米结构中热载流子产生、传输和收集得到了广泛而深入的研究。其中,利用电子隧穿和热发射效应实现的全新光电转换机制,结合平面化制作和CMOS兼容集成等,有望成为硅基红外光电探测的备选方案。目前这... 近年来,表面等离激元(SP)增强的金属纳米结构中热载流子产生、传输和收集得到了广泛而深入的研究。其中,利用电子隧穿和热发射效应实现的全新光电转换机制,结合平面化制作和CMOS兼容集成等,有望成为硅基红外光电探测的备选方案。目前这类探测器主要为金属-半导体肖特基结的光伏型器件,其光电响应较弱。为此,报道了一种基于金属-硅复合无序纳米结构的光电导器件,得益于无序表面等离激元局域热点效应和多叉指金属-半导体-金属(MSM)结构的显著光电导增益,实验获得了硅亚带隙的宽带强光电响应。该热载流子介导的多叉指MSM器件在1310 nm波长处的光电流响应度高达2.50 A/W。 展开更多
关键词 探测器 近红外探测器 光电导探测器 等离激元 光电导增益
原文传递
Effect of soil crust on evaporation and dew deposition in Mu Us sandy land,China 被引量:3
18
作者 Yongliang SUN Xiaoyan LI +3 位作者 Heye XU Zhipeng YANG jia tang Xiaoying ZHANG 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2008年第4期480-486,共7页
The development of soil crust on sandy land may affect the surface hydrological process.This paper investigates the process of evaporation and dew deposition influenced by different soil surface types which were domin... The development of soil crust on sandy land may affect the surface hydrological process.This paper investigates the process of evaporation and dew deposition influenced by different soil surface types which were dominated by sand,primitive biotic crust,and advanced biotic crust,respectively,in the south fringe of Mu Us sandy land in Northwest China from July to September of 2006.The experimental results indicate that the advanced biotic crust could increase evaporation and dew deposition compared to the primitive biotic crust and bare sand although the differences between them were not significant.The average evaporation from advanced biotic crust,primitive biotic crust and sand was 6.8,6.6,and 6.5 mm/d,respectively,and water content is around 16.2%in the condition of initially identical soil.The average dew amount on advanced biotic crust was 0.116 mm/d with extreme 0.05 and 0.24 mm/d.The average values on primitive biotic crust and sand were 0.105 and 0.101 mm/d,respectively,with extreme 0.04 and 0.21 mm/d for both treatments.Also,the dew deposition on advanced biotic crust seemed stable and might rest for a longer time than that on primitive biotic crust and sand.The results suggest that the advanced biotic crust possibly facilitates evaporation and dew deposition.Therefore,the development of biotic crust may potentially enhance the hydrological circulation in the upper sand layer in sandy land. 展开更多
关键词 soil crust EVAPORATION dew deposition sandy land
原文传递
A modified flexible spatiotemporal data fusion model 被引量:2
19
作者 jia tang Jingyu Zeng +8 位作者 Li Zhang Rongrong Zhang Jinghan Li Xingrong Li Jie Zou Yue Zeng Zhanghua Xu Qianfeng Wang Qing Zhang 《Frontiers of Earth Science》 SCIE CAS CSCD 2020年第3期601-614,共14页
Remote sensing spatiotemporal fusion models blend multi-source images of different spatial resolutions to create synthetic images with high resolution and frequency,contributing to time series research where high qual... Remote sensing spatiotemporal fusion models blend multi-source images of different spatial resolutions to create synthetic images with high resolution and frequency,contributing to time series research where high quality observations are not available with sufficient frequency.However,existing models are vulnerable to spatial heterogeneity and land cover changes,which are frequent in human-dominated regions.To obtain quality time series of satellite images in a human-dominated region,this study developed the Modified Flexible Spatial-temporal Data Fusion(MFSDAF)approach based on the Flexible Spatial-temporal Data Fusion(FSDAF)model by using the enhanced linear regression(ELR).Multiple experiments of various land cover change scenarios were conducted based on both actual and simulated satellite images,respectively.The proposed MFSDAF model was validated by using the correlation coefficient(r),relative root mean square error(RRMSE),and structural similarity(SSIM),and was then compared with the Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model(ESTARFM)and FSDAF models.Results show that in the presence of significant land cover change,MFSDAF showed a maximum increase in r,RRMSE,and SSIM of 0.0313,0.0109 and 0.049,respectively,compared to FSDAF,while ESTARFM performed best with less temporal difference of in the input images.In conditions of stable landscape changes,the three performance statistics indicated a small advantage of MFSDAF over FSDAF,but were 0.0286,0.0102,0.0317 higher than for ESTARFM,respectively.MFSDAF showed greater accuracy of capturing subtle changes and created high-precision images from both actual and simulated satellite images. 展开更多
关键词 MFSDAF enhanced linear regression land cover change HETEROGENEOUS time-series
原文传递
Tripodalsporormielones A-C,unprecedented cage-like polyketides with complex polyvdent bridged and fused ring systems 被引量:2
20
作者 Guodong Chen Bingxin Zhao +7 位作者 Meijuan Huang jia tang Yanbing Li Liangdong Guo Rongrong He Dan Hu Xinsheng Yao Hao Gao 《Acta Pharmaceutica Sinica B》 SCIE CAS CSCD 2021年第11期3648-3654,共7页
A chemical investigation on Sporormiella sp.led to the isolation and structural elucidation of tripodalsporormielones Ae C(1-3),a new class of polyketide possessing unprecedented cage-like skeletons with polyvdent bri... A chemical investigation on Sporormiella sp.led to the isolation and structural elucidation of tripodalsporormielones Ae C(1-3),a new class of polyketide possessing unprecedented cage-like skeletons with polyvdent bridged and fused ring systems.These polyketides with cage-like skeletons were characterized as a high non-protonated carbon-containing system,which resulted in few HMBC correlations observed and made the accurate structures hard to be obtained by NMR.Especially,some signals of non-protonated sp;carbons are weak and even unobservable in compound 1.In order to establish the structure of 1,the calculated NMR with DP4 evaluation was applied to determine the structure from the plausible structure candidates obtained from the detailed NMR analysis.Based on NMR experiments and calculated NMR,the structures of isolated compounds were established and confirmed by X-ray technology.Through chiral isolation,the optically pure enantiomers of 1 and 3 were obtained,and their absolute configurations were determined based on ECD quantum chemical calculation.Based on the isolated compounds and our previous work,1-3 would be derived from 3-methylorcinaldehyde,and their plausible biosynthetic mechanism was proposed.Furthermore,1 exhibited obvious short-term memory improvement activity on an Alzheimer’s disease fly model. 展开更多
关键词 Tripodalsporormielones Cage-like polyketides 3-Methylorcinaldehyde Alzheimer’s disease
原文传递
上一页 1 2 下一页 到第
使用帮助 返回顶部