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Identification and virulence test of a new pathogen that causes verticillium striping on rapeseed in northwestern China 被引量:1
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作者 We Si Ruisheng Wang +3 位作者 Mingde Wu Long Yang guoqing li Jing Zhang 《Oil Crop Science》 CSCD 2024年第1期8-19,共12页
Five stems of rapeseed with abundant black microsclerotia were collected from Huangyuan County of Qinghai Province,China,and fungal isolates were obtained from the stems.They were identified based on morphology,molecu... Five stems of rapeseed with abundant black microsclerotia were collected from Huangyuan County of Qinghai Province,China,and fungal isolates were obtained from the stems.They were identified based on morphology,molecular features and specific PCR detection.The results showed that the 10 fungal isolates belonged to Verticillium longisporum lineage A1/D3.One of the 10 isolates(HW7-1)was tested for virulence on three species of rapeseed,including B.napus Zhongshuang 9,B.rapa Qingyou 9 and B.juncea Tayou 2 by conidia inoculation of HW7-1 on roots of young seedlings.Control seedlings were inoculated with V.dahliae conidia or water alone.The seedlings of these treatments were transplanted in culture mix and incubated in a growth chamber(20℃).Results suggested that the control seedlings of three cultivars appeared quite healthy,while the seedlings inoculated with HW7-1 turned yellowing leaves,seedling stunting or even death after 22 days post-inoculation.V.longisporum was re-isolated from he yellow leaves,thus fulfilling Koch's postulates.Moreover,compared to the control treatments,inoculation with HW7-1 caused flowering delay and seed yield reduction on Tayou 2 with production of microsclerotia on the stems.To our knowledge,this is the first report of V.longisporum lineage A1/D3 on rapeseed in northwestern China. 展开更多
关键词 Verticillium longisporum lineage A1/D3 VIRULENCE RAPESEED China
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Antibodies Targeting a Conserved Surface Polysaccharide Are Protective Against a Wide Range of Microbial Pathogens Producing β-1-6-Linked Poly-N-Acetylglucosamine(PNAG)
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作者 Xi Lu guoqing li +4 位作者 Jing Pang Xinyi Yang Colette Cywes-Bentley Xuefu You Gerald B.Pier 《Engineering》 SCIE EI CAS CSCD 2024年第7期69-76,共8页
The b-1-6-linked poly-N-acetylglucosamine(PNAG)polymer is a conserved surface polysaccharide produced by many bacteria,fungi,and protozoan(and even filarial)parasites.This wide-ranging expression makes PNAG an attract... The b-1-6-linked poly-N-acetylglucosamine(PNAG)polymer is a conserved surface polysaccharide produced by many bacteria,fungi,and protozoan(and even filarial)parasites.This wide-ranging expression makes PNAG an attractive target for vaccine development,as it potentially encompasses a broad range of microorganisms.Significant progress has been made in discovering important properties of the biology of PNAG expression in recent years.The molecular characterization and regulation of operons for the production of PNAG biosynthetic proteins and enzymes have been studied in many bacteria.In addition,the physiological function of PNAG has been further elucidated.PNAG-based vaccines and PNAG-targeting antibodies have shown great efficacy in preclinical research.Furthermore,clinical tests for both vaccines and antibodies have been carried out in humans and economically important animals,and the results are promising.Although it is not destined to be a smooth road,we are optimistic about new vaccines and immunotherapeutics targeting PNAG becoming validated and eventually licensed for clinical use against multiple infectious agents. 展开更多
关键词 Poly-N-acetylglucosamine Conjugate vaccine Monoclonal antibody
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Local icariin application enhanced periodontal tissue regeneration and relieved local inflammation in a minipig model of periodontitis 被引量:9
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作者 Xiuli Zhang Nannan Han +4 位作者 guoqing li Haoqing Yang Yangyang Cao Zhipeng Fan Fengqiu Zhang 《International Journal of Oral Science》 SCIE CAS CSCD 2018年第3期168-173,共6页
Periodontitis is an inflammatory autoimmune disease. Treatment should alleviate inflammation, regulate the immune reaction and promote periodontal tissue regeneration. Icariin is the main active ingredient of Epimedii... Periodontitis is an inflammatory autoimmune disease. Treatment should alleviate inflammation, regulate the immune reaction and promote periodontal tissue regeneration. Icariin is the main active ingredient of Epimedii Folium, and it is a promising compound for the enhancement of mesenchymal stem cell function, promotion of bone formation, inhibition of bone resorption, alleviation of inflammation and regulation of immunity. The study investigated the effect of icariin on periodontal tissue regeneration in a minipig model of periodontitis. The minipig model of periodontitis was established. Icariin was injected locally. The periodontal clinical assessment index, a computed tomography(CT) scan, histopathology and enzyme-linked immune sorbent assay(ELISA)were used to evaluate the effects of icariin. Quantitative analysis results 12 weeks post-injection demonstrated that probing depth,gingival recession, attachment loss and alveolar bone regeneration values were(3.72 ± 1.18) mm vs.(6.56 ± 1.47) mm,(1.67 ± 0.59)mm vs.(2.38 ± 0.61) mm,(5.56 ± 1.29) mm vs.(8.61 ± 1.72) mm, and(25.65 ± 5.13) mm3 vs.(9.48 ± 1.78) mm3 in the icariin group and0.9% NaCl group, respectively. The clinical assessment, CT scan, and histopathology results demonstrated significant enhancement of periodontal tissue regeneration in the icariin group compared to the 0.9% NaCl group. The ELISA results suggested that the concentration of interleukin-1 beta(IL-1β) in the icariin group was downregulated compared to the 0.9% NaCl group, which indicates that local injection of icariin relieved local inflammation in a minipig model of periodontitis. Local injection of icariin promoted periodontal tissue regeneration and exerted anti-inflammatory and immunomodulatory function. These results support the application of icariin for the clinical treatment of periodontitis. 展开更多
关键词 Local icariin application enhanced periodontal tissue regeneration and relieved local inflammation in a minipig model of periodontitis ELISA
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Reducing dielectric confinement effect in ionic covalent organic nanosheets to promote the visible-light-driven hydrogen evolution
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作者 guoqing li Xiaolong Zhao +4 位作者 Qihong Yue Ping Fu Fangpei Ma Jun Wang Yu Zhou 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第7期40-46,I0002,共8页
Ultra-thin two-dimensional(2D)organic semiconductors are promising candidates for photocatalysts because of the short charge diffusion pathway and favorable exposure of active sites plus the versatile architecture.Non... Ultra-thin two-dimensional(2D)organic semiconductors are promising candidates for photocatalysts because of the short charge diffusion pathway and favorable exposure of active sites plus the versatile architecture.Nonetheless,the inherent dielectric confinement of 2D materials will induce a strong exciton effect hampering the charge separation.Herein,we demonstrated an effective way to reduce the dielectric confinement effect of 2D ionic covalent organic nanosheets(iCONs)by tailoring the functional group via molecular engineering.Three ultra-thin CONs with different functional groups and the same ionic moieties were synthesized through Schiff base condensation between ionic amino monomer triaminoguanidinium chloride(TG)and aldehyde linkers.The integration of the hydroxyl group was found to significantly increase the dielectric constant by enhancing the polarizability of ionic moieties,and thus reduced the dielectric confinement and the corresponding exciton binding energy(E_(b)).The champion hydroxyl-functional iCON exhibited promoted exciton dissociation and in turn a high photocatalytic hydrogen production rate under visible-light irradiation.This work provided insights into the rationalization of the dielectric confinement effect of low-dimensional photocatalysts. 展开更多
关键词 PHOTOCATALYSIS H_(2)evolution Ionic covalent organic framework NANOSHEETS 2D material Polarization
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Discrimination capacity analysis of FTIR-PCA and EEM-PARAFAC on dandelion tissues extracts
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作者 guoqing li Hui Zou Yilun Chen 《Food Innovation and Advances》 2023年第4期247-254,共8页
Dandelion root contains triterpenoids,polyphenols and flavonoids,dandelion leaf is rich in polyphenols,flavonoids,flavonoids glycosides,and dandelion flower mainly contains flavonoids,among other substances.These diff... Dandelion root contains triterpenoids,polyphenols and flavonoids,dandelion leaf is rich in polyphenols,flavonoids,flavonoids glycosides,and dandelion flower mainly contains flavonoids,among other substances.These different substance content leads to specific benefits and function effects of each part.Fourier transform infrared spectroscopy,three-dimensional fluorescence spectroscopy and related multivariate statistical methods are widely used to determine sample characteristics,but limited research focuses on the substance difference and characteristics in dandelion tissues.In this paper,Fourier transform infrared spectra-principal component analysis and three-dimensional fluorescence spectroscopy-parallel factor analysis were conveyed to analyze dandelion stem,leaf,root and flower tissue extracts,for determining the substance species and content difference among dandelion tissues and evaluating the discrimination capacity of these analysis methods.The Fourier transform infrared spectroscopy of root was distinct from others,and the two principal component models could distinguish dandelion stem and flower,but failed to differentiate leaf and root;while the excitation and emission matrix showed that stem and flower,leaf and root had similar intensity band distribution but different fluorescence intensity,and the parallel factor analysis results proved that one-and threecomponent models cannot differentiate the tissues of stem and flower,leaf and root,since the fluorescent compounds(polyphenol,flavonoid etc.)structure and content were similar in different tissues.These results indicated that Fourier transform infrared-principal component analysis might be a useful method when various fluorescent compounds exist. 展开更多
关键词 analysis FLOWER excitation
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《加拿大多伦多大学东亚图书馆藏中文古籍善本提要》钤印订考 被引量:1
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作者 李国庆 《天禄论丛》 2017年第1期1-57,共57页
加拿大多伦多大学郑裕彤东亚图书馆的“慕氏藏书”是北美中文古籍收藏的重要部分.原收藏者为清末民初的慕学勋.慕氏为山东蓬莱人,网罗帙藏各类图书长达二十二年之久.所收集古籍的范围遍及经、史、子、集各部,编有«蓬莱慕氏藏书目&#... 加拿大多伦多大学郑裕彤东亚图书馆的“慕氏藏书”是北美中文古籍收藏的重要部分.原收藏者为清末民初的慕学勋.慕氏为山东蓬莱人,网罗帙藏各类图书长达二十二年之久.所收集古籍的范围遍及经、史、子、集各部,编有«蓬莱慕氏藏书目».慕氏去世后,藏书的主体被收归多伦多大学.然近百年来该专藏都没有完整书目和书志,鲜为人知,亦甚少为学界所利用.该馆编撰的«加拿大多伦多大学东亚图书馆藏中文古籍善本提要»的出版填补了这一空白,有功学界良多.然受条件所限,其钤印部分的著录当时并没做完.藏书印的正确著录有助于了解古籍版本的流传过程,一些印文提供的信息亦有利于纠正过去对某些人物字号的错误记载.受出版社和该书主编委托,本人对其作了订补考释,披露于此,供学界研究参考. 展开更多
关键词 多伦多大学东亚图书馆 慕氏藏书 慕学勋 古籍善本 藏书印
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雕虫小记 被引量:1
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作者 李国庆 《天禄论丛》 2016年第1期16-33,共18页
本文是个人辨释中文古籍上的藏书印文字,以及追索印主的或成功或失败的经验记录.按中国学术传统,相对于“明明德”和“止于至善”的“大学”而言,文字学只是基础,故称之为“小学”.不过我们这一批人,现代化的大学都读过了,传统的“小学... 本文是个人辨释中文古籍上的藏书印文字,以及追索印主的或成功或失败的经验记录.按中国学术传统,相对于“明明德”和“止于至善”的“大学”而言,文字学只是基础,故称之为“小学”.不过我们这一批人,现代化的大学都读过了,传统的“小学”往往并不通.笔者就是如此,在实践当中深感有补课的必要.把这数条“雕虫小记”借学刊发表,供正在或将要编辑古籍书目的东亚同人指正. 展开更多
关键词 藏书印 古文字 篆籀 藏书家 印鉴数据库
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北美五馆中文古籍钤印经眼录 被引量:1
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作者 李国庆 《天禄论丛》 2018年第1期116-152,共37页
本文汇集北美五家图书馆藏中文古籍所钤藏书印章,略加考订,按各馆所编目录编号罗列于下,供学界研究参考.
关键词 北美图书馆 中文古籍 书目 藏书印
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新加坡国立大学图书馆中文古籍鉴藏印汇考
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作者 李国庆 《天禄论丛》 2023年第1期65-207,共143页
新加坡国立大学图书馆所藏的中文古籍上所铃印章的释读结果,供学界研究参考。
关键词 新加坡国立大学图书馆 中文古籍 藏书印
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北美四校中文古籍鉴藏印考略
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作者 李国庆 《天禄论丛》 2022年第1期35-80,共46页
在过去的一年多时间里,四家北美高校图书馆所藏的中文古籍书目编成出版了。作者将这些古籍上所钤印章的释读结果按各馆所编古籍目录的编号公布,以利学界研究参考。
关键词 北美图书馆 中文古籍书目 藏书印
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北美四家图书馆中文古籍钤印经眼录 被引量:1
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作者 李国庆 《天禄论丛》 2020年第1期196-217,共22页
本文汇集北美四家图书馆所藏中文古籍所钤藏书印章,略加考订,按该馆所编古籍目录编号罗列于下,供学界研究参考。
关键词 北美图书馆 古籍书目 藏书印
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大麻二酚的抗炎和抑菌活性研究 被引量:4
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作者 刘娟 余思宜 +3 位作者 翟文丽 李国庆 李学涛 刘继涛 《日用化学工业》 CAS 北大核心 2021年第7期655-661,共7页
采用CCK-8法考察大麻二酚(CBD)对HaCat细胞和RAW264.7细胞相对细胞活性的影响。采用LPS诱导的HaCat细胞和RAW264.7细胞炎症模型考察CBD对炎症因子分泌的抑制作用。采用抑菌环和抑菌率等实验方法对CBD抑制厌氧菌痤疮丙酸杆菌(P.acnes)的... 采用CCK-8法考察大麻二酚(CBD)对HaCat细胞和RAW264.7细胞相对细胞活性的影响。采用LPS诱导的HaCat细胞和RAW264.7细胞炎症模型考察CBD对炎症因子分泌的抑制作用。采用抑菌环和抑菌率等实验方法对CBD抑制厌氧菌痤疮丙酸杆菌(P.acnes)的效果进行测试。结果表明,CBD浓度低于20μmol/L时,其对正常/炎症HaCat细胞以及正常/炎症RAW264.7细胞均无细胞毒性,也不会促进相关细胞的增殖分化;CBD对炎症RAW264.7模型中TNF-α具有良好的抑制作用,10μmol/L浓度下与阳性对照地塞米松(DEX)效果相当,对两种炎症模型中IL-6均有显著抑制作用,20μmol/L浓度下对两种炎症模型中IL-1β均有显著抑制作用,浓度为10、20μmol/L时对两种炎症模型中IFN-γ均有显著抑制作用,表明其具有良好的抗炎活性;将CBD乳液作用于P.acnes,实验结果显示CBD浓度在20μmol/L及以上时对P.acnes有显著抑制作用。此外,抑菌率实验结果表明,CBD浓度为80μmol/L时对P.acnes的抑菌率高达99%,表明其具有良好的抑菌功效。 展开更多
关键词 大麻二酚 抗炎 痤疮丙酸杆菌 抑菌
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道德伟绩耀海外——袁同礼先生与俄亥俄州立大学东亚图书馆
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作者 李国庆 《天禄论丛》 2011年第1期17-22,共6页
俄亥俄州立大学东亚图书馆之创办人是袁同礼先生一手栽培的,此后的第一继任者也受过袁先生的教诲。本文借此一史实阐扬袁先生培植人才、提携后进对海外东亚图书馆事业的伟大贡献,表达一个后辈的景仰和怀念之情。
关键词 俄亥俄州立大学 东亚图书馆 袁同礼 创办人 继任者 袁先生 怀念之情 伟大贡献
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以同好会,为忘年交:海外老一代学人散记(二)——以本馆近日所收陈颖教授的师友题赠本为线索
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作者 李国庆 《天禄论丛》 2015年第1期178-202,共25页
本文是«以同好会,为忘年交:海外老一代学人散记»之二(之一登载在«天禄论丛»第四卷上),通过介绍俄亥俄州立大学东亚语言文学系教授陈颖先生捐赠给该校东亚图书馆的近200种师友弟子的题赠本当中的一部分,反映老一代... 本文是«以同好会,为忘年交:海外老一代学人散记»之二(之一登载在«天禄论丛»第四卷上),通过介绍俄亥俄州立大学东亚语言文学系教授陈颖先生捐赠给该校东亚图书馆的近200种师友弟子的题赠本当中的一部分,反映老一代海外学人的学问才艺,诗酒风流,以及花果飘零的人世沧桑. 展开更多
关键词 陈颖 题赠本 海外汉学界 传统学人
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Prediction of coal structure using particle size characteristics of coalbed methane well cuttings 被引量:4
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作者 Shuaifeng Lv Shengwei Wang +3 位作者 Rui li guoqing li Ming Yuan Jiacheng Wang 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2019年第2期209-216,共8页
Severely deformed coal seams barely deliver satisfactory gas production. This research was undertaken to develop a new method to predict the positions of deformed coals for a horizontal CBM well. Firstly, the drilling... Severely deformed coal seams barely deliver satisfactory gas production. This research was undertaken to develop a new method to predict the positions of deformed coals for a horizontal CBM well. Firstly, the drilling cuttings of different structure coals were collected from a coal mine and compared. In light of the varying cuttings characteristics for different structure coals, the coal structure of the horizontally drilled coal seam was predicted. And the feasibility of this prediction method was discussed. The result shows that exogenetic fractures have an important influence on the deformation of coal seams. The hardness coefficient of coal decreases with the deformation degree in the order of primary structural, cataclastic and fragmented coal. And the expanding-ratio of gas drainage holes and the average particle size of cuttings increase with the increase of the deformation degree. The particle size distribution of coal cuttings for the three types of coals is distinctive from each other. Based on the particle size distribution of cuttings from X-2 well in a coal seam, six sections of fragmented coal which are unsuitable for perforating are predicted. This method may benefit the optimization of perforation and fracturing of a horizontal CBM well in the study area. 展开更多
关键词 COAL structure Gas drainage BOREHOLES Particle size distribution of COAL CUTTINGS Directional CBM WELL Optimization of PERFORATION
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深松与翻耕对旱地小麦花后根系干重及产量的影响 被引量:4
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作者 李国清 石岩 《农业科学》 2012年第1期1-4,共4页
通过田间试验,研究了深松和翻耕2种耕作方式对旱地小麦花后根系干重及产量的影响。结果表明,上层土壤(0 cm^20 cm)根系干重及占个时期总根重比重翻耕耕作处理大于深松处理;深层土壤(20 cm^100 cm)中小麦根系的分布深松的重量要比翻耕处... 通过田间试验,研究了深松和翻耕2种耕作方式对旱地小麦花后根系干重及产量的影响。结果表明,上层土壤(0 cm^20 cm)根系干重及占个时期总根重比重翻耕耕作处理大于深松处理;深层土壤(20 cm^100 cm)中小麦根系的分布深松的重量要比翻耕处理的大;深层土壤(20 cm^100 cm)中根系干重占各时期根重的比重比翻耕处理的高,同时深松处理的籽粒产量中来自灌浆期的增加比重要大于翻耕处理的,这样有利于提高穗粒数,从而提高旱地小麦产量。 展开更多
关键词 深松 翻耕 旱地小麦 根系干重 产量
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Mandible exosomal ssc-mir-133b regulates tooth development in miniature swine via endogenous apoptosis 被引量:5
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作者 Ye li Xinxin Wang +6 位作者 Jiali Ren Xiaoshan Wu guoqing li Zhipeng Fan Chunmei Zhang Ang li Songlin Wang 《Bone Research》 SCIE CAS CSCD 2018年第4期408-417,共10页
Signal transduction between different organs is crucial in the normal development of the human body. As an important medium for signal communication, exosomes can transfer important information, such as microRNAs(miRN... Signal transduction between different organs is crucial in the normal development of the human body. As an important medium for signal communication, exosomes can transfer important information, such as microRNAs(miRNAs), from donors to receptors.MiRNAs are known to fine-tune a variety of biological processes, including maxillofacial development; however, the underlying mechanism remains largely unknown. In the present study, transient apoptosis was found to be due to the expression of a miniature swine maxillofacial-specific miRNA, ssc-mir-133b. Upregulation of ssc-mir-133b resulted in robust apoptosis in primary dental mesenchymal cells in the maxillofacial region. Cell leukemia myeloid 1(Mcl-1) was verified as the functional target, which triggered further downstream activation of endogenous mitochondria-related apoptotic processes during tooth development.More importantly, mandible exosomes were responsible for the initial apoptosis signal. An animal study demonstrated that ectopic expression of ssc-mir-133 b resulted in failed tooth formation after 12 weeks of subcutaneous transplantation in nude mice. The tooth germ developed abnormally without the indispensable exosomal signals from the mandible. 展开更多
关键词 In As
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Community structure and assembly of denitrifying bacteria in epiphytic biofilms in a freshwater lake ecosystem 被引量:2
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作者 guoqing li Dingbo YAN +3 位作者 Pinhua XIA Haipeng CAO Tao liN Yin YI 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2022年第3期1039-1050,共12页
Denitrifying bacteria are a crucial component of aquatic ecosystem in nitrogen cycle.However,the denitrifying bacterial community dynamics and structure in epiphytic biofilms remain unexplored.The abundance of denitri... Denitrifying bacteria are a crucial component of aquatic ecosystem in nitrogen cycle.However,the denitrifying bacterial community dynamics and structure in epiphytic biofilms remain unexplored.The abundance of denitrification gene(nir)and structure of nirS-denitrifying bacterial community in the epiphytic biofilms collected in July and November of 2018 from a typical plateau lake(Caohai Wetland,Guizhou,China)were studied by Real-time Quantitative Polymerase Chain Reaction(qPCR)and highthroughput sequencing.Results show that the gene abundance of nirK was higher than that of nirS(P<0.05),and it was significantly different during the growth period(July)than the decline period(November).The denitrifying bacterial species was similar in the two months and shared 76.18%of OTUs.Proteobacteria(56.55%±22.15%)was the dominant phylum in all the samples.Epiphytic biofilms between growth period and decline period displayed significantly different microbial community structures due to differences in species abundance.Water temperature was the crucial factor that affected the denitrifying microbial community structure in our study.Environmental factors explain only partially the dynamic characteristics of denitrifying microbial communities,implying that the stochastic processes affected the construction of denitrifying microbial communities.As the null model analysis results show,dispersal limitation(stochastic)and undominated processes significantly influenced the assembly of denitrifying microbial communities.This study broadened our understanding of the denitrifying bacterial community structure and its function on epiphytic biofilms in freshwater ecosystems with new information provided. 展开更多
关键词 denitrifying bacteria epiphytic biofilms community assembly null model
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Response of density-related fine root production to soil and leaf traits in coniferous and broad-leaved plantations in the semiarid loess hilly region of China 被引量:1
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作者 Meimei Sun Bo-Chao Zhai +2 位作者 Qiu-Wen Chen guoqing li Sheng Du 《Journal of Forestry Research》 SCIE CAS CSCD 2022年第3期1071-1082,共12页
Fine roots are the most active and functional component of root systems and play a significant role in the acquisition of soil resources. Density is an important structural factor in forest plantations but information... Fine roots are the most active and functional component of root systems and play a significant role in the acquisition of soil resources. Density is an important structural factor in forest plantations but information on changes in fine roots along a density gradient is limited. In this study, plantations of black locust (Robinia pseudoacacia L.) and Chinese pine (Pinus tabuliformis Carr.) with four density classes were analyzed for the influence of soil and leaf traits on fine root growth. Fine root biomass increased with stand density. High fine root biomass was achieved through increases in the fine root production and turnover rate in the high-density black locust plantations and through an increase in fine root production in the pine plantations. In the high-density Chinese pine stand, there was a high fine root turnover which, coupled with high fine root production, contributed to a high fine root biomass. Overall, fine root production and turnover rate were closely related to soil volumetric water content in both kinds of plantations, while fine root biomass, especially the component of necromass, was related to soil nutrient status, which refers to phosphorous content in black locust plantations and nitrogen content in Chinese pine plantations. There was a close linkage between leaf area index and fine root dynamics in the black locust plantations but not in the pine plantations. 展开更多
关键词 Fine roots Black locust Chinese pine SEMIARID Soil moisture Leaf area index
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嵌入铂单原子的苯并咪唑基共价有机框架实现高效可见光析氢
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作者 马方沛 汤庆平 +8 位作者 席识博 李国庆 陈涛 凌星辰 吕忆农 刘云鹏 赵小龙 周瑜 王军 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第5期137-149,共13页
氢气(H_(2))是一种清洁的无碳燃料,具有很高的能量密度,是化石能源的潜在替代品之一.半导体光催化水分解反应可将取之不竭的太阳能转化为氢气中的化学能,从而提供一条有前途的、经济和环境友好的产氢路线.光催化析氢反应(HER)涉及光捕... 氢气(H_(2))是一种清洁的无碳燃料,具有很高的能量密度,是化石能源的潜在替代品之一.半导体光催化水分解反应可将取之不竭的太阳能转化为氢气中的化学能,从而提供一条有前途的、经济和环境友好的产氢路线.光催化析氢反应(HER)涉及光捕集、激发、电荷分离和传输,以及表面质子还原过程.光激发态通常在几皮秒内发生,通过辐射或非辐射复合弛豫返回到基态,然而,光生电子迁移到表面并触发两电子的质子还原是一个慢过程,时间通常在几毫秒或以上.整个过程中转换效率因光生电子极易复合而大大降低.因此,如何延长光生电子寿命,促进电子及时传递到表面析氢位点,提高催化位点的析氢速率,是设计水分解高效光催化剂的关键,也是该领域的难题.有机半导体催化剂可以从地球丰度高的轻元素制备,具有成本低、毒性小和结构多样等特点.其中一个典型代表是共价有机框架(COFs),其具有大的比表面积及丰富可调的骨架组成和孔道结构,在分子水平上的可设计性具有独特优势.苯并咪唑化合物具有较大极性和灵活可调的π共轭结构,被广泛用作光电器件的共轭辅助分子.以苯并咪唑基单体直接合成的COF种类罕见,且未见相关COF用于光催化反应的报道.本文通过选用不对称的苯并咪唑单体(2-(4-氨基苯基)-5-氨基苯并咪唑)与三醛基间苯三酚直接通过席夫碱化学反应缩合,制备了苯并咪唑基COF.该COF材料有效促进了光吸收和电荷分离/传递,以及高活性Pt单原子析氢位点的形成,在可见光驱动的析氢反应中表现出较好的析氢速率和转换频率.采用微波辅助的溶剂热策略快速合成了苯并咪唑基COF(PABZ-Tp),通过X射线衍射、傅立叶变换红外吸收光谱、13C固态核磁共振等研究其结构.光学和光电化学表征结果表明,PABZ-Tp在可见光范围.内展现出较好的光吸收,具有较低的激子解离能(17.8 meV),有效促进了长寿命自由光电子的形成.骨架中带负电荷的苯并咪唑基团不但是Pt单原子形成和稳定的主要因素,还有助于构建良好的电子迁移通道,从而有效促进了光生电子快速传递到表面Pt单原子位点,使得该催化剂在可见光驱动的析氢反应中表现出较高的催化效率,析氢速率高达115 mmol g^(-1)h^(-1),转换频率为4475.1 h^(-1).理论计算结合瞬态吸收光谱等实验结果表明,苯并咪唑COF框架是产生高活性的关键,对于光吸收、电荷分离传递以及高效析氢位点的构筑均起了重要作用.综上,本文构筑了一种高效的COF基有机光催化剂用于可见光析氢过程.展示了使用不对称咪唑基单体构筑功能化COF材料的广阔前景. 展开更多
关键词 共价有机框架 光催化 析氢 单原子催化 可持续能源
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