期刊文献+
共找到200篇文章
< 1 2 10 >
每页显示 20 50 100
“族化”语境下大学生的心理健康教育对策探究
1
作者 李春梅 《河南牧业经济学院学报》 2019年第2期78-80,共3页
为逃避现实生活压力,或是对同辈群体的盲目认同,或是在人格方面存在一定缺陷,当代大学生出现了“低头族”“透支族”“校漂族”等群体性现象。由于“族化”群体人数众多、种类繁多且差异性较大,“族化”呈现出的心理问题基本都是群体性... 为逃避现实生活压力,或是对同辈群体的盲目认同,或是在人格方面存在一定缺陷,当代大学生出现了“低头族”“透支族”“校漂族”等群体性现象。由于“族化”群体人数众多、种类繁多且差异性较大,“族化”呈现出的心理问题基本都是群体性的,这对新时代的大学生心理健康教育提出了挑战。高校心理健康教育应该分年级或群体开设心理健康教育课程,努力营造良好校园文化环境,倡导健康文明的生活方式,构建全方位支持保障体系,有效帮助大学生缓解压力,积极应对“族化”给大学生成长成才带来的不良影响。 展开更多
关键词 “族化” 同辈群体 群体性心理问题
下载PDF
高校毕业生“族化”生存现象及破解之道
2
作者 贾阳 周小乐 《高等农业教育》 北大核心 2014年第11期85-87,共3页
大学生就业问题是关乎社会稳定和经济发展的重大问题.在就业压力的影响下,高校毕业生群体不断催生出“蚁族”“啃老族”“候鸟族”“校漂族”等生存现象,影响到大学生的职业发展和社会的和谐稳定.政府需要深化综合改革和健全政策体系,... 大学生就业问题是关乎社会稳定和经济发展的重大问题.在就业压力的影响下,高校毕业生群体不断催生出“蚁族”“啃老族”“候鸟族”“校漂族”等生存现象,影响到大学生的职业发展和社会的和谐稳定.政府需要深化综合改革和健全政策体系,高校需要深化教育改革和完善服务体系,大学生需要科学合理定位和主动适应环境,共同寻找破解之道. 展开更多
关键词 高校毕业生 “族化”群体 政策体系 服务体系
原文传递
文化共享情境下白依人族群文化复兴实践的现代困境 被引量:5
3
作者 和少英 解语 《青海民族研究》 CSSCI 北大核心 2020年第1期52-57,共6页
在现代社会,族群文化复兴一方面是为了加强族群认同,另一方面也成为了一种族群文化资源推动民族地区经济社会发展。本文基于云南省鹤庆县彝族支系白依人的田野调查材料,讨论了以"密息会"为中心进行的族群文化复兴实践,解析了&... 在现代社会,族群文化复兴一方面是为了加强族群认同,另一方面也成为了一种族群文化资源推动民族地区经济社会发展。本文基于云南省鹤庆县彝族支系白依人的田野调查材料,讨论了以"密息会"为中心进行的族群文化复兴实践,解析了"密息会"这种文化要素怎样被生活于当地的白族、汉族和白依人所共享的情境。当前某些地方的族群文化复兴实践较易导致文化"族别化",而现代社会中族际之间的文化交流与文化共享已成为一种明显的社会事实。因此,需要反思族群文化复兴实践导致的文化"族别化"困境,这对于促进社会整合和中华民族文化的整体发展具有重要意义。 展开更多
关键词 白依人 密息会 共享 “族化”
下载PDF
Chalcogenide-based S-scheme heterojunction photocatalysts
4
作者 Chunguang Chen Jinfeng Zhang +3 位作者 Hailiang Chu Lixian Sun Graham Dawson Kai Dai 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第8期81-108,共28页
The unique photocatalytic mechanism of S-scheme heterojunction can be used to study new and efficient photocatalysts.By carefully selecting semiconductors for S-scheme heterojunction photocatalysts,it is possible to r... The unique photocatalytic mechanism of S-scheme heterojunction can be used to study new and efficient photocatalysts.By carefully selecting semiconductors for S-scheme heterojunction photocatalysts,it is possible to reduce the rate of photogenerated carrier recombination and increase the conversion efficiency of light into energy.Chalcogenides are a group of compounds that include sulfides and selenides(e.g.,CdS,ZnS,Bi_(2)S_(3),MoS_(2),ZnSe,CdSe,and CuSe).Chalcogenides have attracted considerable attention as heterojunction photocatalysts owing to their narrow bandgap,wide light absorption range,and excellent photoreduction properties.This paper presents a thorough analysis of S-scheme heterojunction photocatalysts based on chalcogenides.Following an introduction to the fundamental characteristics and benefits of S-scheme heterojunction photocatalysts,various chalcogenide-based S-scheme heterojunction photocatalyst synthesis techniques are summarized.These photocatalysts are used in numerous significant photocatalytic reactions,in-cluding the reduction of carbon dioxide,synthesis of hydrogen peroxide,conversion of organic matter,generation of hydrogen from water,nitrogen fixation,degradation of organic pollutants,and sterilization.In addition,cutting-edge characterization techniques,including in situ characterization techniques,are discussed to validate the steady and transient states of photocatalysts with an S-scheme heterojunction.Finally,the design and challenges of chalcogenide-based S-scheme heterojunction photocatalysts are explored and recommended in light of state-of-the-art research. 展开更多
关键词 PHOTOCATALYSIS CHALCOGENIDE S-scheme heterojunction Charge separation Application
下载PDF
Chalcogen heteroatoms doped nickel-nitrogen-carbon single-atom catalysts with asymmetric coordination for efficient electrochemical CO_(2) reduction
5
作者 Jialin Wang Kaini Zhang +5 位作者 Ta Thi Thuy Ng Yiqing Wang Yuchuan Shi Daixing Wei Chung-Li Dong Shaohua Shen 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第9期54-65,共12页
The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2) reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into... The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2) reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into the symmetric nickel-nitrogen-carbon(Ni-N_(4)-C)configuration to obtain Ni-X-N_(3)-C(X:S,Se,and Te)SACs with asymmetric coordination presented for central Ni atoms.Among these obtained Ni-X-N_(3)-C(X:S,Se,and Te)SACs,Ni-Se-N_(3)-C exhibited superior eCO_(2)RR activity,with CO selectivity reaching~98% at-0.70 V versus reversible hydrogen electrode(RHE).The Zn-CO_(2) battery integrated with Ni-Se-N_(3)-C as cathode and Zn foil as anode achieved a peak power density of 1.82 mW cm^(-2) and maintained remarkable rechargeable stability over 20 h.In-situ spectral investigations and theoretical calculations demonstrated that the chalcogen heteroatoms doped into the Ni-N_(4)-C configuration would break coordination symmetry and trigger charge redistribution,and then regulate the intermediate behaviors and thermodynamic reaction pathways for eCO_(2)RR.Especially,for Ni-Se-N_(3)-C,the introduced Se atoms could significantly raise the d-band center of central Ni atoms and thus remarkably lower the energy barrier for the rate-determining step of ^(*)COOH formation,contributing to the promising eCO_(2)RR performance for high selectivity CO production by competing with hydrogen evolution reaction. 展开更多
关键词 Electrochemical CO_(2) reduction reaction Chalcogen heteroatoms Single-atom catalysts Asymmetric coordination CO production
下载PDF
Leaf Volatiles Induced by Mechanical Damage from Diverse Taxonomic Tree Species 被引量:2
6
作者 平立岩 沈应柏 +1 位作者 金幼菊 郝建华 《Acta Botanica Sinica》 CSCD 2001年第3期261-266,共6页
Plant volatiles induced by wounding play key roles in plant-insect and plant-plant interactions. To deeply understand the mechanism of their induction by wounding and their functions in interplant communications, four... Plant volatiles induced by wounding play key roles in plant-insect and plant-plant interactions. To deeply understand the mechanism of their induction by wounding and their functions in interplant communications, four diverse tree species: ashleaf maples ( Acer negundo L.), hankow willow (Salix matsudana Koidz.), Chinese white poplar ( Populus tomentosa Carr.) and poplar opera 8277 (P. simonii x P. pyramibalis cv.), were used as materials. The blends of volatiles collected after damage were detected with GCMS. Most of the induced compounds reach high concentrations in 5 h. They are acyclic monoterpenes, fatty acid derivatives, and aromatic compounds. To authors' knowledge, dimethyl adipate, diisobutyl succinate and benthothiazole have never been reported in previous herbivore insect-plant systems, After being damaged 2 h, green leaf volatiles were released in large amount. The repellents were detected in higher concentration after 24 h. The time of releasing is different within different species, but many kinds of volatiles widely existed in different trees. There were some difference among species. Health ashleaf maple released more terpenoids, but poplars and willow produced more aromatic compounds. 展开更多
关键词 VOLATILES damage GC-MS TERPENOID fatty acid derivative aromatic compound
下载PDF
Recent progress in CO oxidation over Pt-group-metal catalysts at low temperatures 被引量:10
7
作者 林坚 王晓东 张涛 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第11期1805-1813,共9页
CO oxidation is probably the most studied reaction in heterogeneous catalysis.This reaction has become a hot topic with the discovery of nanogold catalysts,which are active at low temperatures(at or below room temper... CO oxidation is probably the most studied reaction in heterogeneous catalysis.This reaction has become a hot topic with the discovery of nanogold catalysts,which are active at low temperatures(at or below room temperature).Au catalysts are the benchmark for judging the activities of other metals in CO oxidation.Pt-group metals(PGMs) that give comparable performances are of particular interest.In this mini-review,we summarize the advances in various PGM(Pt,Pd,Ir,Rh,Ru)catalysts that have high catalytic activities in low-temperature CO oxidation arising from reducible supports or the presence of OH species.The effects of the size of the metal species and the importance of the interface between the metal and the reducible support are covered and discussed in terms of their promotional role in CO oxidation at low temperatures. 展开更多
关键词 Carbon monoxide oxidation GOLD Platinum group metal Low temperature Size effect INTERFACE
下载PDF
Pheasants in sacred and other forests in western Sichuan: their cultural conservation 被引量:2
8
作者 王楠 郑光美 Philip J.K.McGowan 《Chinese Birds》 2012年第1期33-46,共14页
Buddhism and local cultural traditions have long protected wildlife species and their habitats in Tibetan-dominated areas of western Sichuan. In Daocheng County, the White Eared-pheasant (Crossoptilon crossoptilon) ha... Buddhism and local cultural traditions have long protected wildlife species and their habitats in Tibetan-dominated areas of western Sichuan. In Daocheng County, the White Eared-pheasant (Crossoptilon crossoptilon) has been afforded special protection by local people because it is conspicuous and white, a color with special symbolism for Buddhists. This and other cultural reasons have led to pheasants and forests benefiting in some areas. Pheasants were found during surveys between January 2003 and June 2004 in forests with varying degrees of local (non-formal) protection. However, there were significant signs that these traditional attitudes were changing in the face of three particular pressures brought to bear by better roads, improving access to and from the rest of China. The first was the development of a significant local demand for the Chinese caterpillar fungus (Cordyceps sinesis), which is much sought after throughout East Asia and mushrooms. Second, and more recent, is a dramatic increase in tourism from major Chinese cities, bringing non-Tibetan values into Daocheng County and changing the local attitudes to all animals. And then, there is a rise in income of the local population, resulting in a higher timber demand for building big houses, which impact all wildlife in the forest, but local attitudes to sacred forests have been retained so far in spite of this increased timber demand. Lessons should be learnt from the impact that unregulated tourism at Chonggu monastery, the most visited area in the county, has on the surrounding forests so that other sacred and non-sacred forests can best be protected for the long term. The alternative is that several Tibetan Plateau Galliformes, currently considered non-threatened because of their extensive distribution in a remote area, cannot be guaranteed such a healthy future. 展开更多
关键词 cultural conservation Tibetan BUDDHISM wildlife White Eared-pheasant Crossoptilon crossoptilon
下载PDF
Molecular Composition and Evolution of the Chalcone Synthase (CHS) Gene Family in Five Species of Camellia (Theaceae) 被引量:5
9
作者 杨俊波 田欣 +1 位作者 李德铢 郭振华 《Acta Botanica Sinica》 CSCD 2003年第6期659-666,共8页
The molecular composition and evolution of the chalcone synthase (CHS) gene family from five species in Camellia (Theaceae) are explored in this study. Sixteen CHS exon 2 from four Camellia species were amplified from... The molecular composition and evolution of the chalcone synthase (CHS) gene family from five species in Camellia (Theaceae) are explored in this study. Sixteen CHS exon 2 from four Camellia species were amplified from total DNA by PCR method. Three sequences of the fifth species in Camellia and two sequences of Glycine max as the designated outgroups were obtained from GenBank. Our results indicated that CHS gene family in Camellia was differentiated to three subfamilies (A, B, C) during the evolutionary history with six groups (A1, A2, A3, BI, B2, C). Among them, only group A2 was possessed by all five species in this study. However, the other five groups were detected only in some species of the plants studied. All members of CHS gene family in this study had high sequence similarity, more than 90% among the members in the same subfamily and more than 78% among different subfamilies at nucleotide level., According to the estimated components of amino acids, the function of CHS genes in Camellia had been diverged. The nucleotide substitutions of the different groups were not identical. Based on phylogenetic analyse inferred from sequences of CHS genes and their deduced amino acid sequences, we concluded that the CHS genes with new function in this genus were evolved either by mutations on several important sites or by accumulation of the mutations after the gene duplication. A further analysis showed that the diversification of CHS genes in Camellia still occurred recently, and the evolutionary models were different to some extant among different species. So we assumed that the different evolutionary models resulted from the impacts of variable environmental elements after the events of speciation. 展开更多
关键词 CAMELLIA chalcone synthase (CHS) gene family molecular evolution
下载PDF
Thermodynamic analysis of growth of ternary Ⅲ-Ⅴ semiconductor materials by molecular-beam epitaxy
10
作者 叶志成 舒永春 +5 位作者 曹雪 龚亮 皮彪 姚江宏 邢晓东 许京军 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第1期146-151,共6页
Thermodynamic models for molecular-beam epitaxy(MBE) growth of ternary Ⅲ-Ⅴ semiconductor materials are proposed.These models are in agreement with our experimental materials InGaP/GaAs and InGaAs/InP,and reported ... Thermodynamic models for molecular-beam epitaxy(MBE) growth of ternary Ⅲ-Ⅴ semiconductor materials are proposed.These models are in agreement with our experimental materials InGaP/GaAs and InGaAs/InP,and reported GaAsP/GaAs and InAsP/InP in thermodynamic growth.The lattice strain energy △G and thermal decomposition sensitive to growth temperature are demonstrated in the models simultaneously.△G is the function of the alloy composition,which is affected by flux ratio and growth temperature directly.The calculation results reveal that flux ratio and growth temperature mainly influence the growth process.Thermodynamic model of quaternary InGaAsP/GaAs semiconductor material is discussed also. 展开更多
关键词 semiconductor materials Ⅲ-Ⅴ compounds GROWTH THERMODYNAMICS
下载PDF
New Xanthones from Swertia decora 被引量:1
11
作者 肖怀 陆阳 +2 位作者 陈泽乃 刘光明 钱金栿 《Journal of Chinese Pharmaceutical Sciences》 CAS 2001年第4期172-174,共3页
From the CHCl3 part of Swertia decora Franch., a traditional medicinal herb of China, two new xanthones, swertiadecoraxanthone-I and swertiadecoraxanthone-II along with four known compounds have been isolated and iden... From the CHCl3 part of Swertia decora Franch., a traditional medicinal herb of China, two new xanthones, swertiadecoraxanthone-I and swertiadecoraxanthone-II along with four known compounds have been isolated and identified on the basis of spectral analysis and chemical evidence. 展开更多
关键词 Swertia decora GENTIANACEAE XANTHONE Swertiadecoraxanthone-II
下载PDF
Hydroxylation Polymorphisms of S─mephenytoin aDebrisoquin in Native Normal Chinese Zhuang MinorityVolunteers
12
作者 匡唐永 罗其葵 +2 位作者 张家美 邹安庆 楼雅卿 《Journal of Chinese Pharmaceutical Sciences》 CAS 1995年第2期99-106,共8页
S─mephenytoin and debrisoquin hydroxylation abilities were investigated in 118 normal Chinese Zhuang minority volunteers after co─administration po 100 mg racemic mephenytoin(MP)and 10 mg debrisoquin (DB). The rat... S─mephenytoin and debrisoquin hydroxylation abilities were investigated in 118 normal Chinese Zhuang minority volunteers after co─administration po 100 mg racemic mephenytoin(MP)and 10 mg debrisoquin (DB). The ratio between S─and R─enantiomers of mephenytoin in urinewas determined by implication of GC─NPD and used as the measure of the drug hydroxylation. 2 ofthe 118 subjects had S/R ratios greater than 1.0 and were poor hydroxylators of S─mephenytoin. The frequency of S─mephenytoin poor metabolizers (PM) was 10.2%. No PM of debrisoquin was found in the volunteers. It indicated that there was no relationship between S─mephenytoin P(4′)─ hydroxylation and debrisoquin 4─hydroxylation polymorphisms in Chinese Zhuang Minority population. In addition, 16 of the 118 volunteers(4 PMs and 12 EMs of S-mephenytoin) were se─lected to conduct the elimination kinetic studies of racemic mephenytoin and debrisoquin in urine. The pharmacokinetic parameters of S─, R─mephenytoin, DB and 4─OH─DB were calculated. 展开更多
关键词 MEPHENYTOIN Debrisoquin HYDROXYLATION Inheritic polymorphism Pharma─cokinetics Gas chromatography
下载PDF
Identification of Odor Volatile Compounds and Deodorization ofPaphia undulata Enzymatic Hydrolysate 被引量:12
13
作者 CHEN Deke CHEN Xin +6 位作者 CHEN Hua CAI Bingna WAN Peng ZHU Xiaolian SUN Han SUN Huili PAN Jianyu 《Journal of Ocean University of China》 SCIE CAS 2016年第6期1101-1110,共10页
Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase mi- croextraction gas chromatography mass spectrometry (HS-SPME-GC-MS) analysis of volatiles from unt... Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase mi- croextraction gas chromatography mass spectrometry (HS-SPME-GC-MS) analysis of volatiles from untreated samples and three deodorized samples (under the optimal conditions) ofPaphia undulata enzymatic hydrolysate revealed that the compounds contrib- uting to the distinctive odor were 1-octen-3-ol, n-hexanal, n-heptanal, 2,4-heptadienal, and 2,4-decadienal, whereas n-pentanal, n-octanal, n-octanol, benzaldehyde, 2-ethylfuran and 2-pentylfuran were the main contributors to the aromatic flavor. The deodoriz- ing effects of activated carbon (AC) adsorption, yeast extract (YE) masking and tea polyphenol (TP) treatment on a P. undulata en- zymatic hydrolysate were investigated using orthogonal experiments with sensory evaluation as the index. The following optimized deodorization conditions were obtained: AC adsorption (35 mg mL-1, 80℃, 40 rain), YE masking (7 mgmL l, 45 ℃, 30 min) and TP treatment (0.4mgmL-l, 40℃, 50min). AC adsorption effectively removed off-flavor volatile aldehydes and ketones. YE masking modified the odor profile by increasing the relative contents of aromatic compounds and decreasing the relative contents of aldehydes and ketones. The TP treatment was not effective in reducing the odor score, but it significantly reduced the relative content of alde- hydes while increasing that of alkanes. It is also notable that TP effectively suppressed trimethylamine (TMA) formation in a P. un- dulate hydrolysate solution for a period of 72 h. 展开更多
关键词 DEODORIZATION OFF-FLAVOR TRIMETHYLAMINE enzymatic hydrolysate Paphia undulate
下载PDF
Expansion of the Actin Gene Family in Amphioxus
14
作者 魏云虎 张煜珺 +1 位作者 陈源 毛炳宇 《Zoological Research》 CAS CSCD 北大核心 2009年第5期473-479,共7页
Actins are a small family of ubiquitous proteins that are essential cytoskeletal components and are highly conserved during evolution. Actins are usually divided into two classes, the cytoplasmic and muscle actins, wh... Actins are a small family of ubiquitous proteins that are essential cytoskeletal components and are highly conserved during evolution. Actins are usually divided into two classes, the cytoplasmic and muscle actins, which have different functional roles. Here we systematically analyzed the actin genes in the genome of the primitive chordate amphioxus (Branchiostoma floridae). We found that amphioxus contains more than 30 actin genes, many of which are linked. Phylogenetic analysis suggests the amphioxus actin genes have clearly undergone extensive expansion through tandem duplications. The actin genes' structure also varies a lot, containing 2 to 7 exons. We also cloned two muscle type of actin genes from the amphioxus (B. belcheri) and compared their expression patterns during early development. The slight difference in their expression suggests functional diversification of these actin genes. Our results shed light on the evolution both of actin genes themselves and their functional roles in chordate development. 展开更多
关键词 AMPHIOXUS ACTIN Gene family EVOLUTION Expression pattern
下载PDF
Systematic analysis of components and contents in Houttuynia cordata Thunb 被引量:4
15
作者 Xin-Yi Dong Yi Jin Li-Ping Yang 《Traditional Medicine Research》 2017年第4期176-188,共13页
Objective:This study aims to provide the material basis for the molecular mechanism of Yuxingcao(Houttuynia cordata Thunb,HCT)through the method of evidence-based study to summarize the natural constituents isolated f... Objective:This study aims to provide the material basis for the molecular mechanism of Yuxingcao(Houttuynia cordata Thunb,HCT)through the method of evidence-based study to summarize the natural constituents isolated from HCT.Methods:We searched CNKI,Wanfang,VIP,Pubmed and relevant conference compilations.The keywords were'Yuxingcao or Houttuynia cordata Thunb'and'components'or'ingredients'or'constituent'or'volatile oil'or'flavonoids'or'terpene'or'content',both in Chinese and English.According to the inclusion and exclusion criteria,the reported compositions and contents have been summarized,and SPSS software was used to draw the boxplot of contents.Results:A total of 603 natural compounds in 11 categories were obtained from pooled articles.In the diverse components,the number of aliphatic compounds(n=259)and terpenoids(n=158)are more than those of flavonoids(n=26),alkaloids(n=42)and aromatics(n=42).While,in the part of volatile oils of HCT,the largest components are aliphatic compounds(mainly distributed on the ground)and terpenoids(mainly distributed in the underground).Although,methyl n-nonylketone is distributed in the whole herb plant,a large proportion is present in the underground parts.As for non-volatiles,the flavonoid content(mainly distributed on the ground)was the highest,among which quercetin and its glycosyl derivatives were the prominent.Conclusion:The results of this study provide a more comprehensive material basis for the further study of HCT.It is also helpful to explain the mechanisms of anti-oxidant,anti-inflammatory,anti-bacterial,anti-viral and anti-cancer effects from the molecular target and molecular network levels. 展开更多
关键词 Houttuynia cordata Thunb INGREDIENT CONTENT Aliphatics TERPENOIDS FLAVONOIDS
下载PDF
Evolution of plant microRNA gene families 被引量:14
16
作者 Aili Li Long Mao 《Cell Research》 SCIE CAS CSCD 2007年第3期212-218,共7页
MicroRNAs (miRNAs) are important post-transcriptional regulators of their target genes in plants and animals, miRNAs are usually 20-24 nucleotides long. Despite their unusually small sizes, the evolutionary history ... MicroRNAs (miRNAs) are important post-transcriptional regulators of their target genes in plants and animals, miRNAs are usually 20-24 nucleotides long. Despite their unusually small sizes, the evolutionary history of miRNA gene families seems to be similar to their protein-codingcounterparts. In contrast to the small but abundant miRNA families in the animal genomes, plants have fewer but larger miRNA gene families. Members of plant miRNA gene families are often highly similar, suggesting recent expansion via tandem gene duplication and segmental duplication events. Although many miRNA genes are conserved across plant species, the same gene family varies significantly in size and genomic organization in different species, which may cause dosage effects and spatial and temporal differences in target gene regulations. In this review, we summarize the current progress in understanding the evolution of plant miRNA gene families. 展开更多
关键词 MICRORNAS post-transcriptional regulation tandem duplication segmental duplication
下载PDF
Characterization of Humic Fractions in a ^(15)N-labelled Soil by Solid-State ^(13)C and ^(15)N NMR 被引量:4
17
作者 CHENG LILI, WEN QIXIAO and CHEN BIYUN Institute of Soil Science, the Chinese Academy of Sciences, Nanjing 210008 (China) 《Pedosphere》 SCIE CAS CSCD 2001年第2期151-157,共7页
Five humic fractions were obtained from a uniformly 15N-labelled soil by extraction with 0.1 mol L-1 Na4P207, 0.1 mol L-1 NaOH, and HF/HCI-0.1 mol L-1 NaOH, consecutively, and analyzed by 13C and 15N CPMAS NMR (cross ... Five humic fractions were obtained from a uniformly 15N-labelled soil by extraction with 0.1 mol L-1 Na4P207, 0.1 mol L-1 NaOH, and HF/HCI-0.1 mol L-1 NaOH, consecutively, and analyzed by 13C and 15N CPMAS NMR (cross polarization and magic angle spinning nuclear magnetic resonance). Compared with those of native soils humic fractions studied as a whole contained more alkyls, methoxyls and O-alkyls, being 27%-36%, 17%-21% and 36%-40%, respectively, but fewer aromatics and carboxyls (being 14%-20% and 13%-90%, respectively). Among those humic fractions, the humic acid (HA) and fulvic acid (FA) extracted by 0.1 mol L-1 Na4P207 contained slightly more carboxyls than corresponding humic fractions extracted by 0.1 mol L-1 NaOH, and the HA extracted by 0.1 mol L-1 NaOH after treatment with HF/HCI contained the least aromatics and carboxyls. The distribution of nitrogen functional groups of soil humic fractions studied was quite similar to each other and also quite similar to that of humic fraction from native soils. More than 75% of total N in each fraction was in amide form, with 9%-13% present as aromatic and/or aliphatic amines and the remainder as hoterocyclic N. 展开更多
关键词 AROMATICITY 13C CPMAS NMR humic substances 15N CPMAS NMR nitrogen forms
下载PDF
The tyrosinase gene family and albinism in fish 被引量:3
18
作者 王家庆 侯林 +5 位作者 张瑞锋 赵欣涛 姜丽娟 孙文静 安家璐 李晓燕 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2007年第2期191-198,共8页
Tyrosinase exists universally in organisms and is a characteristic enzyme of melanocytes. Tyrosinase family genes in vertebrates consist of 3 related members; tyrosinase (TYR, Tyr), tyro sinase-related protein-1 (T... Tyrosinase exists universally in organisms and is a characteristic enzyme of melanocytes. Tyrosinase family genes in vertebrates consist of 3 related members; tyrosinase (TYR, Tyr), tyro sinase-related protein-1 (TRP-1, Tyrp 1), and tyro sinase-related protein-2 (TRP-2, Tyrp2, Dct). These proteins catalyze melanin biosynthesis in pigment cells and play important roles in determining vertebrate coloration. Transcription of the TYR and TRP genes is useful for studying neural crest and optic vesicle cell migration and differentiation during emblyogenesis and important in pigment rescue in fish. In this paper, the structure of gene and protein molecular evolution, function and roles of the TYR family in fish were reviewed. 展开更多
关键词 FISH tyrosinase gene family molecular evolution TRANSGENE ALBINISM
下载PDF
Inhibitory Effects of Aromatic Compounds on Soil Nitrification 被引量:4
19
作者 ZHANG Li-Li WU Zhi-Jie +3 位作者 SHI Yun-Feng CHEN Li-Jun SONG Yu-Chao JUAN Ying-Hua 《Pedosphere》 SCIE CAS CSCD 2010年第3期326-333,共8页
Aromatic compounds (ACs) in soil can induce competitive inhibition for soil NH3 oxidation, and nitrification inhibitors can be used to this end. A laboratory incubation experiment was performed with 12 nitroaromatic c... Aromatic compounds (ACs) in soil can induce competitive inhibition for soil NH3 oxidation, and nitrification inhibitors can be used to this end. A laboratory incubation experiment was performed with 12 nitroaromatic compounds (NACs), 15 amidoaromatic compounds (AACs) and 20 hydroxyaromatic compounds (HACs) to assess the inhibitory effects of ACs on soil nitrification. Based on these results, the critical and optimal concentrations of ACs were determined for better inhibitory effects. Most of the test ACs were able to inhibit soil nitrification; the effectiveness differed with soil type. Among the ACs, the NACs with m-nitryl, amino or hydroxyl and the AACs with a nitro group or a chlorine atom on aromatic ring or with a p-hydroxyl were more effective. 3-nitroaniline, 4-aminophenol and 3-nitrophenol showed the greatest potential as nitrification inhibitors. The critical concentration of these compounds in brown soil and cinnamon soil was found to be 0.5 mg kg-1 soil. Due to the toxicity, carcinogenicity and mutagenicity of ACs, further toxicological and ecotoxicological research is necessary before ACs are used as nitrification inhibitors in agricultural and horticultural practices. 展开更多
关键词 amidoaromatic compounds ammonia oxidation hydroxyaxomatic compounds nitrification inhibition nitroaromatic compounds
下载PDF
Characterization of Basic Nitrogen Aromatic Species Obtained during Fluid Catalytic Cracking by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry 被引量:8
20
作者 Liu Yingrong Wang Wei +3 位作者 Hu Qiuling Zhu Yuxia Deng Jinghui Tian Songbai 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2012年第2期18-24,共7页
The basic-nitrogen aromatic compounds in feedstocks and liquid products from the micro-reactor and soluble components of coke obtained during fluid catalytic cracking (FCC) process were analyzed by the micro-electro... The basic-nitrogen aromatic compounds in feedstocks and liquid products from the micro-reactor and soluble components of coke obtained during fluid catalytic cracking (FCC) process were analyzed by the micro-electrospray ioniza- tion (ESI) 9.4T Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with an average mass resolving power of 300 000 at a mass range of 100--1 200. The analytical results revealed that the coker gas oil (CGO) contained a higher abundance of basic-nitrogen aromatic compounds with the type of-SN to -9N compared with those in deasphalted oil (DAO) and mixed FCC feedstock. After catalytic cracking, the abundance of lowly condensed basic-nitrogen aromatic compounds was much less than those of highly condensed aromatics in the liquid products, with the carbon number mainly ranging from 6 to 25 and the average carbon number of the side-chains equating to 1--5. On the contrary, with respect to the soluble components of coke, the abundance of lowly condensed basic-nitrogen aromatic compounds was more than those of highly condensed aromatics, and the carbon number ranged from 12 to 30, which was much smaller than that of the mixed FCC feedstock but slightly larger than that of the cracked liquid products. These results have provided some fundamental information on FCC process. 展开更多
关键词 FCC basic-nitrogen aromatic compounds ESI FT-ICR MS
下载PDF
上一页 1 2 10 下一页 到第
使用帮助 返回顶部