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基于改进YOLOv8的轻量化小麦病害检测方法 被引量:14
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作者 马超伟 张浩 +3 位作者 马新明 王键霖 张永爽 张小艾 《农业工程学报》 EI CAS CSCD 北大核心 2024年第5期187-195,共9页
为提高小麦病害检测精度,实现将模型方便快速部署到移动端,该研究提出了一种基于改进YOLOv8的轻量化小麦病害检测方法。首先,使用PP-LCNet模型替换YOLOv8网络结构的骨干网络,并在骨干网络层引入深度可分离卷积(depthwise separable conv... 为提高小麦病害检测精度,实现将模型方便快速部署到移动端,该研究提出了一种基于改进YOLOv8的轻量化小麦病害检测方法。首先,使用PP-LCNet模型替换YOLOv8网络结构的骨干网络,并在骨干网络层引入深度可分离卷积(depthwise separable convolution, DepthSepConv)结构,减少模型参数量,提升模型检测性能;其次,在颈部网络部分添加全局注意力机制(global attention mechanism, GAM)模块,强化特征中语义信息和位置信息,提高模型特征融合能力;然后,引入轻量级通用上采样内容感知重组(content-aware reassembly of features,CARAFE)模块,提高模型对重要特征的提取能力;最后,使用Wise-IoU(weighted interpolation of sequential evidence for intersection over union)边界损失函数代替原损失函数,提升网络边界框回归性能和对小目标病害的检测效果。试验结果表明,对于大田环境下所采集的小麦病害数据集,改进后模型的参数量及模型大小相比原YOLOv8n基线模型分别降低了12.5%和11.3%,同时精确度(precision)及平均精度均值(mean average precision,m AP)相较于原模型分别提高了4.5和1.9个百分点,优于其他对比目标检测算法,可为小麦病害检测无人机等移动端检测装备的部署和应用提供参考。 展开更多
关键词 图像识别 深度学习 目标检测 轻量化 小麦病害 YOLOv8 PP-LCNet
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Human AKR1A1 involves in metabolic activation of carcinogenic aristolochic acidⅠ
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作者 GAO Zhenna YOU Xinyue +6 位作者 LIU Weiying WU Jiaying XI Jing CAO Yiyi ZHANG Xiaohong ZHANG Xinyu LUAN Yang 《中国药理学与毒理学杂志》 CAS 北大核心 2024年第9期641-651,共11页
OBJECTIVE To investigate whether aldo-keto reductases(AKRs)can act as a nitrore⁃ductase(NR)and bioactivate aristolochic acidⅠ(AA-Ⅰ)to produce AA-Ⅰ-DNA adducts.METHODS①Human-induced hepatocytes(hiHeps)and human bla... OBJECTIVE To investigate whether aldo-keto reductases(AKRs)can act as a nitrore⁃ductase(NR)and bioactivate aristolochic acidⅠ(AA-Ⅰ)to produce AA-Ⅰ-DNA adducts.METHODS①Human-induced hepatocytes(hiHeps)and human bladder RT4 cells were used as tool cells and treated with AA-Ⅰ0,0.5,1.0 and 2μmol·L^(-1)for 24 h.Cell viability was detected using the CCK-8 method,and the half maximal inhibition concentration(IC_(50))was calculated using the CCK-8 method and the level of DNA adduct production was calculated.②hiHeps and RT4 cells were treated with AKR inhibitor luteotin(0,5,10 and 25μmol·L^(-1))+AA-Ⅰ0.2 and 1.0μmol·L^(-1)for 24 h,respectively,and the levels of DNA adducts were detected by a liquid chromatography-tandem mass spectrometer(LC-MS/MS).③hiHeps cells were incubated with 80 nmol·L^(-1)small interfering RNAs(si-AKRs)for 48 h and treated with AA-Ⅰ1.0μmol·L^(-1)for 24 h.Real-time qualitative PCR(RT-qPCR)method was used to detect the mRNA expression of AKRs gene and LC-MS/MS technology was used to investigate the effect of specific AKR gene knockdown on DNA adduct levels.④500 nmol·L^(-1)human AKR recombinant proteins AKR1A1 and AA-Ⅰwere incubated in vitro under anaerobic conditions and the formation of AA-Ⅰ-DNA adducts was detected.RESULTS①The IC_(50)of AA-Ⅰto hiHeps and RT4 cells was 1.9 and 0.42μmol·L^(-1),respec⁃tively.The level of DNA adduct production of the two cell lines was significantly different(P<0.01).②Luteolin≥5μmol·L^(-1)significantly inhibited the production of AA-Ⅰ-DNA adducts in both cells(P<0.05),and there was a concentration-dependent effect in hiHeps cells(P<0.01,R=0.84).③In the AKR family,the knockdown of AKR1A1 gene up to 80%inhibited the generation of AA-Ⅰ-DNA adducts by 30%-40%.④The AA-Ⅰ-DNA adducts were detected in the incubation of recombinant protein AKR1A1 and AA-Ⅰunder anaerobic conditions in vitro,approximately 1 adduct per 107 nucleotides.CONCLU⁃SION AKR1A1 is involved in AA-Ⅰbioactivation,providing a reference for elucidation of the carcino⁃genic mechanism of AA-Ⅰ. 展开更多
关键词 metabolic activation nitro-reduction aldo-keto reductase superfamily aristolochic acidⅠ
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Two Novel Hydroperoxylated Lycopodium Alkaloids from Huperzia serrata 被引量:3
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作者 谭昌恒 马晓强 +2 位作者 周慧 蒋山好 朱大元 《Acta Botanica Sinica》 CSCD 2003年第1期118-121,共4页
Two novel hydroperoxylated Lycopodium alkaloids, 11alpha-hydroperoxyphlegmariurine B (1) and 7-hydroperoxyphlegmariurine B (2), along with a known compound, phlegmanurine B (3), were isolated from the total alkaloid f... Two novel hydroperoxylated Lycopodium alkaloids, 11alpha-hydroperoxyphlegmariurine B (1) and 7-hydroperoxyphlegmariurine B (2), along with a known compound, phlegmanurine B (3), were isolated from the total alkaloid fraction of the Chinese medicinal herb Huperzia serrata (Thunb.) Trev. Their structures and relative configurations were elucidated on the basis of spectroscopic analyses. 展开更多
关键词 Huperzia serrata Lycopodium alkaloids 11 alpha-hydroperoxyphlegmariurine B 7-hydroperoxyphlegmaniurine B
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Cloning of Potato POTHR-1 Gene and Its Expression in Response to Infection by Phytophthora infestans and Other Abiotic Stimuli 被引量:8
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作者 田振东 柳俊 +1 位作者 谢从华 宋波涛 《Acta Botanica Sinica》 CSCD 2003年第8期959-965,共7页
A complete cDNA of potato Phytophthora infestans-induced hypersensitive response-related protein gene (POTHR-1) was cloned using rapid amplification of cDNA ends (RACE) strategy according to a fragment sequence which ... A complete cDNA of potato Phytophthora infestans-induced hypersensitive response-related protein gene (POTHR-1) was cloned using rapid amplification of cDNA ends (RACE) strategy according to a fragment sequence which we had cloned using suppression subtractive hybridization (SSH) technique. The potato POTHR-1 gene encodes a protein of 225 amino acids, which shares 81% identity with tobacco hin1 gene-enoded protein (harpin-induced protein). Southern blot revealed that there are two to three copies of POTHR-1 in potato genome. The POTHR-1 gene expression in potato leaves showed that its transcripts accumulated remarkably in leaves after 36 h inoculation with P. infestans. Mechanical wounding and jasmonic acid (JA) could induce the POTHR-1 gene expression and osmotic stress just induce a slight accumulation of POTHR-1 gene mRNA, while salicylic acid (SA) had no detectable function on the induction accumulation of POTHR-1 gene transcripts. The potato POTHR-1 gene may preferentially associate with hypersensitive response (HR) or biotic cell death during interaction between host and pathogen. 展开更多
关键词 cDNA cloning POTHR-1 gene POTATO Phytophthora infestans
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The in vitro Anti Hptocarcinoma Effects of Human Interleukin-12 from Transgenic Potato 被引量:4
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作者 陈佳瑜 许洁 葛正龙 《Agricultural Science & Technology》 CAS 2010年第4期47-49,共3页
[Objective]The aim was to examine the anti heptocarcinoma effects of human interleukin-12(hIL-12) from transgenic potatoes.[Method]Human heptocarcinoma cell line HepG22.2.15 was cocultured with human peripherial blo... [Objective]The aim was to examine the anti heptocarcinoma effects of human interleukin-12(hIL-12) from transgenic potatoes.[Method]Human heptocarcinoma cell line HepG22.2.15 was cocultured with human peripherial blood monocyte(PBMC).Human IL-12 extracted from its transgenic patatoes was introduced to this coculture system.MTT method and laser confocal microscope were then employed to evaluate its survival rates and morphological changes of HepG22.2.15 cell line.[Result]The HepG22.2.15 survival rate of the plant produced hIL-12 treated group was significantly lower than that of the wild type control,while similar to that of commercial purified recombinant hIL-12 group.As indicated by AnnexinV/PI double staining laser confocal microscope,cocultured heptocarcinoma cells showed the typical early and final phase apoptotic morphological characteristics 48 hours after 2 × 10-4 mg/L potato secreted hIL-12 treatment.[Conclusion] These results demonstrated that Heptocarcinoma HepG22.2.15 cell growth could be actively inhibited by the transgenic potato expressed hIL-12 in vitro. 展开更多
关键词 Hman interleukin-12 Anti-tumor effects Transgenic potato
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High Altitude Adaptation and Phylogenetic Analysis of Tibetan Horse Based on the Mitochondrial Genome 被引量:9
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作者 徐树青 洛桑江白 +7 位作者 华桑 何健 阿叁次仁 王威 童晓梅 梁羽 汪建 郑晓光 《Journal of Genetics and Genomics》 SCIE CAS CSCD 北大核心 2007年第8期720-729,共10页
To investigate genetic mechanisms of high altitude adaptations of animals living in the Tibetan Plateau, three mitochondrial genomes (mt-genome) of Tibetan horses living in Naqu (4,500 m) of Tibetan, Zhongdian (3... To investigate genetic mechanisms of high altitude adaptations of animals living in the Tibetan Plateau, three mitochondrial genomes (mt-genome) of Tibetan horses living in Naqu (4,500 m) of Tibetan, Zhongdian (3,300 m) and Deqin (3,100 m) of Yunnan province were sequenced. The structures and lengths of these three mt-genomes are similar to the Cheju horse, which is related to Tibetan horses, but little shorter than the Swedish horse. The pair-wise identity of these three horses on nucleotide level is more than 99.3%. When the gene encoding the mitochondrial protein of Tibetan horses was analyzed, we found that NADH6 has higher non-synonymous mutation rate in all of three Tibetan horses. This implies that NADH6 may play a role in Tibetan horses' high altitude adaptation. NADH6 is one of the subunits of the complex I in the respiratory chain. Furthermore, 7 D-loop sequences of Tibetan horse from different areas were sequenced, and the phylogeny tree was constructed to study the origin and evolutionary history of Tibetan horses. The result showed that the genetic diverse was high among Tibetan horses. All of Tibetan horses from Naqu were clustered into one clade, and Tibetan horses from Zhongdian and Deqin were clustered into others clades. The first molecular evidence of Tibetan horses indicated in this study is that Tibetan horse population might have multiple origins. 展开更多
关键词 Tibetan horses mitochondrial genome high altitude adaptation NADH6 PHYLOGENY
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马基雅维里悖论解析 被引量:3
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作者 俞可平 《北京大学学报(哲学社会科学版)》 CSSCI 北大核心 2017年第6期11-24,共14页
马基雅维里的政治思想充满着明显的悖论,这些悖论集中体现于他关于理想国家、政治主体和伦理道德的主要观点之中。这些悖论不仅在政治思想史上有着深远的意义,而且也有其认识论的和现实政治的基础,应当着重从方法论原则、政治制度、社... 马基雅维里的政治思想充满着明显的悖论,这些悖论集中体现于他关于理想国家、政治主体和伦理道德的主要观点之中。这些悖论不仅在政治思想史上有着深远的意义,而且也有其认识论的和现实政治的基础,应当着重从方法论原则、政治制度、社会转型和个性品质等角度去分析产生这些悖论的主客观原因。马基雅维里的悖论,深刻地反映了天国与尘世、人性与兽性、传统与近代、理想与现实之间的张力和矛盾。马基雅维里既先知般地发现了人类政治发展的规律和趋势,又深刻地洞察了政治统治的策略和权谋。远离贪婪自私、不择手段、欺诈陷害、暴力专制、残酷无情等违逆人类本性和历史潮流的"马基雅维里主义"消极遗产,在新的历史条件下弘扬马基雅维里所倡导的理性、尊严、自由、民主和共和,是人类政治发展和文明进步的唯一正道。 展开更多
关键词 雅维里 君主制 共和制 统治术 政治主体 政治道德
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Removal of Endosymbiosis Agrobacterium from Transgenic Potato 被引量:1
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作者 王敬东 石磊 +2 位作者 陈晓军 张丽 宋玉霞 《Agricultural Science & Technology》 CAS 2011年第11期1576-1579,共4页
[Objective] This research aimed to solve the problems of growth and differentiation inhibition of transgenic potato plants caused by antibiotics used for bacteriostasis. [Method] Microtubers were induced using transge... [Objective] This research aimed to solve the problems of growth and differentiation inhibition of transgenic potato plants caused by antibiotics used for bacteriostasis. [Method] Microtubers were induced using transgenic potato plants, which had generated shoots and formed transgenic bacteria-free plants. [Result] Among the three transgenic potato varieties, the optimal induction medium for SⅠ and SⅡ were MS+ 0.5 mg/L of 6-BA + 0.1 mg/L of GA3+ 150 mg/L of cef, and the optimal induction medium for NT were MS+ 0.5 mg/L of ZT + 0.1 mg/L of GA3 + 150 mg/L of cef; the optimal differentiation medium for tubers were MS+ 0.5 mg/L of ZT + 0.1 mg/L of NAA, and the tubers with diameters ranging from 0.5 to 0.7 cm had generated the most shoots. The transgenic bacteria-free plants were cultivated in propagation medium without antibiotics for 30 d with a contamination rate of 0, and the stems of bacteria-free plants were stout with no branching. [Conclusion] This method is simple and could be easily applied for the removal of bacteria, which had cleared away obstacles for the selection and growth of transgenic individuals. 展开更多
关键词 POTATO Transgenic plant Antibiotic MICROTUBER Bacteria-free
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业界资讯
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《现代制造》 2003年第7期94-94,96,98,共3页
中日韩三国业界欲统一托盘标准 日本托盘租赁株式会社(JSR)国际事业部主任叶山弘最近来华访问,参观了中国物资储运总公司和中国物资储运协会,了解了中国物流市场和托盘的使用情况。 目前,美洲和欧洲的托盘都有统一的标准,但亚太地区还... 中日韩三国业界欲统一托盘标准 日本托盘租赁株式会社(JSR)国际事业部主任叶山弘最近来华访问,参观了中国物资储运总公司和中国物资储运协会,了解了中国物流市场和托盘的使用情况。 目前,美洲和欧洲的托盘都有统一的标准,但亚太地区还没有。 展开更多
关键词 中国物资储运 物流成本 企业 企业管理 业界资讯 小型航空发动机 洗涤设备 产品目录 基马 海狮 第四季度 印刷机械 拉动式生产 干洗机
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The Effect of Benzyltetrahydropalmatine (BTHP) on Action Potentials and the Two Components of Delayed Rectifying Potassium Currents in Guinea Pig Ventricular Myocytes 被引量:1
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作者 阎升 李新华 +5 位作者 姚伟星 夏国瑾 江明性 黄文龙 黄枕亚 彭司勋 《Journal of Chinese Pharmaceutical Sciences》 CAS 1998年第4期47-50,共4页
The effects of BTHP on Ca 2+ independent action potential and the two components of delayed rectifier potassium currents were studied in guinea pig single ventricular myocytes by using whole cell patch clamp tec... The effects of BTHP on Ca 2+ independent action potential and the two components of delayed rectifier potassium currents were studied in guinea pig single ventricular myocytes by using whole cell patch clamp technique. BTHP 30 μmol·L -1 significantly prolonged APD 90 from 143±16 ms to 184±21 ms ( P 【0.01, n=5) without affecting either the RP or APA, and the APD prolonging effects of BTHP were independent of extracellular Ca 2+ . BTHP inhibited both I kr (IC 50 =7 9 μmol·L -1 ) and I ks (IC 50 =22 4 μmol·L -1 ) in a concentration dependent fashion. The results demon strated that BTHP had no obvious selectivity for I kr and I ks . 展开更多
关键词 Benzyltetrahydropalmatine Patch clamp technique Delayed rectifier potassium channel Ventricular myocytes
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Identification of sika deer and red deer using partial cytochrome b and 12s ribosomal RNA genes 被引量:7
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作者 李波 白素英 +2 位作者 徐艳春 张伟 马建章 《Journal of Forestry Research》 SCIE CAS CSCD 2006年第2期160-162,共3页
A study was conducted on the identifications of the degraded samples of sika deer (Cervus nippon) and red deer (Cervus elaphus) by phylogenetic and nucleotide distance analysis of partial Cytb and 12s rRNA genes s... A study was conducted on the identifications of the degraded samples of sika deer (Cervus nippon) and red deer (Cervus elaphus) by phylogenetic and nucleotide distance analysis of partial Cytb and 12s rRNA genes sequences. 402 bp Cytb genes were achieved by PCR-sequencing using DNA extracted from 8 case samples, and contrasted with 27 sequences of Cytb gene downloaded from GenBank database. The values of three nucleotide distance between three suspected samples and sika deer were identical (0.026±0.006), which was smaller than the smallest nucleotide distance between eastern red deer and sika deer (0.036). Furthermore, phylogenetic analysis of sika deer and red deer indicated that the evidences located within the same cluster as sika deer. The evidences were sika deer materials. As the same way, other three suspected samples were derived from red deer. The results were further confirmed by phylogenetic and nucleotide distance analysis of 387 bp 12s rRNA gene. The method was powerful and less time-consuming and helpful to reduce the related cases with wildlife. 展开更多
关键词 Sika deer (Cervus nippon) Red deer (Cervus elaphus) Cytochrome b gene (Cytb) 12s ribosomal RNA gene (12s rRNA)
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ISCHEMIC PRECONDITIONING RELIEVES ISCHEMIA/REPERFUSION INJURY OF HIPPOCAMPUS NEURONS IN RAT BY INHIBITING p53 AND BAX EXPRESSIONS 被引量:6
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作者 Hui-min Liu Jing-xin Li Lian-bi Chen 《Chinese Medical Sciences Journal》 CAS CSCD 2007年第2期123-127,共5页
Objective To examine whether ischemic preconditioning (IPC) can protect neuron against delayed death in CA1 subfield of hippocampus following reperfusion of a lethal ischemia in rats, and explore the role of p53 and b... Objective To examine whether ischemic preconditioning (IPC) can protect neuron against delayed death in CA1 subfield of hippocampus following reperfusion of a lethal ischemia in rats, and explore the role of p53 and bax in this process. Methods We examined the effect of IPC on delayed neuron death, neuron apoptosis, expressions of p53 and bax gene in the CA1 area of hippocampus in the rats using HE staining, flow cytometry, RT-PCR, and immunohistochemistry technique. Results IPC enhanced the quantity of survival cells in the CA1 region of hippocampus (216±9 cells/0.72 mm2 vs. 30±5 cells/0.72 mm2, P<0.01), decreased the percentages of apoptotic neurons of hippocampus caused by ischemia/reperfusion (2.06%±0.21% vs. 4.27%±0.08%, P<0.01), and weakened the expressions of p53 and bax gene of hippocampus compared with ischemia/reperfusion without IPC. Conclusion IPC can protect the neurons in the CA1 region of hippocampus against apoptosis caused by ische- mia/reperfusion, and this process may be related to the reduced expressions of p53 and bax. 展开更多
关键词 RAT HIPPOCAMPUS ischemic preconditioning P53 BAX
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Effects of Different Natural Organic Additives on in Vitro Shoot Regeneration of Raphanus sativus L. Var, Beeralu 被引量:1
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作者 Indeewari Manawadu Nilanthi Dahanayake Senanayakage Gamini Nonis Senanayake 《Journal of Agricultural Science and Technology(A)》 2014年第3期219-223,共5页
Abstract: Raphunus sativus L. commonly known as "radish" is a popular vegetable crop used by people all over the world for its culinary and medicinal properties. Enhancement of in vitro regeneration system for radi... Abstract: Raphunus sativus L. commonly known as "radish" is a popular vegetable crop used by people all over the world for its culinary and medicinal properties. Enhancement of in vitro regeneration system for radish variety beeralu is needed to further tissue culture studied. Therefore, the present study was carried out to find out the effects of different organic additives on in vitro shoot regeneration of Radish (Raphanus sativus L.) Var. Beeralu. Hypocotyl explants of aseptic plantlets were cultured on MS basal medium supplemented with 2.5 mg/L BAP (benzyl adenine) and 0.1 mg/L NAA (1-nphthaleneacetic acid) with different natural additives; 20% coconut water, 20% coconut milk, 10% grind spinach leaves, 10% grind potato tubers, 10% grind carrot, 5% rice flour, 10% green gram, 10% grind pumpkin, 10% banana fruit, 10% orange and control (without any additives). Complete randomized design (CRD) with five replicates was used. After one month the numbers of regenerated shoots were counted and statistical analysis was carried out using the Student Newman-Kuells Means Separation Test of SAS program (9.1.3). The highest mean number of shoots (12 shoots/explant) from Radish (Raphanus sativus L.) Var. Beeralu observed in MS basal medium with 2.5 mg/L BAP and 0.1 mg/L NAA with 10% orange juice whereas the 2nd highest shoots were obtained with 20% coconut water. The lowest number of shoots (0 shoot/explant) was observed from medium with carrot juice and pumpkin juice, but they induced callus formation. Media with grind spinach leaves, rice flour, green gram, grind potato tubers and banana inhibit the shoot regeneration. 展开更多
关键词 Raphunus sativus L. natural additives orange juice in vitro regeneration.
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Differential mercury volatilization by tobacco organs expressing a modi-fied bacterial merA gene 被引量:14
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作者 HE YU KE, JIAN GE SUN, XIAN ZHONG FENG, MIHALY CZAKU, LASZLO MARTON Depariment of Biological Sciences, University of South Carolina, 700 Sumter Street, Columbia, SC29208, USA National Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Phy 《Cell Research》 SCIE CAS CSCD 2001年第3期231-236,共6页
Mercury pollution is a major environmental problem accompanying industrial activities. Most of the mercury released ends up and retained in the soil as complexes of the toxic ionic mercury (Hg2+), which then can be co... Mercury pollution is a major environmental problem accompanying industrial activities. Most of the mercury released ends up and retained in the soil as complexes of the toxic ionic mercury (Hg2+), which then can be converted by microbes into the even more toxic methylmercury which tends to bioaccumulate. Mercury detoxification of the soil can also occur by microbes converting the ionic mercury into the least toxic metallic mercury (Hg0) form, which then evaporates. The remediation potentia1 of transgenic plants carrying the MerA gene from E. coLi encoding mercuric ion reductase could be evaluated. A modified version of the gene, optimized for plant codon preferences (merApe9, Rugh et al. 1996), was introduced into tobacco by Agrobacterium-mediated leaf disk transformation. Transgenic seeds were resistant to HgCl2 at 50 μM and some of them (10-20% ) could germinate on media containing as much as 350 μM HgCl2, while the control plants were fully inhibited or died on 50 μM HgCl2. The rate of elemental mercury evolution from Hg2+ (added as HgCl2) was 5-8 times higher for transgenic plants than the control. Mercury volatilization by isolated organs standardized for fresh weight was higher (up to 5 times) in the roots than in shoots or the leaves. The data suggest that it is the root system of the transgenic plants that volatilizes most of the reduced mercury (Hg0). It also suggests that much of the mercury need not enter the vascular system to be transported to the leaves for volatilization. Thansgenic plants with the merApe9 gene may be used to mercury detoxification for environmental improvement in mercury-- contaminated regions more efficiently than it had been predicted based on data on volatilization of whole plants via the upper parts only (Rugh et al. 1996). 展开更多
关键词 Environment heavy metals mercury remediation tobacco.
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Developmental expression of Cyclin H and Cdk7 in zebrafish: the essential role of Cyclin H during early embryo development 被引量:7
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作者 Qing Yun Liu Zhi Li Wu +2 位作者 Wen Jian Lv Yuan Chang Yan Yi Ping Li 《Cell Research》 SCIE CAS CSCD 2007年第2期163-173,共11页
Cyclin-dependent kinase 7 (Cdk7) is the catalytic subunit of the metazoan Cdk-activating kinase (CAK). Activation of Cdk7 requires its association with a regulatory subunit, Cyclin H. Although the Cdk7/Cyclin H co... Cyclin-dependent kinase 7 (Cdk7) is the catalytic subunit of the metazoan Cdk-activating kinase (CAK). Activation of Cdk7 requires its association with a regulatory subunit, Cyclin H. Although the Cdk7/Cyclin H complex has been implicated in the regulation ofRNA polymerase in several species, the precise function of their orthologs in zebrafish has not been fully elucidated. In this study, we isolated from zebrafish blastula embryos two cDNAs encoding the orthologs of human Cyclin H and Cdk7, and examined the role of Cdk7/Cyclin H in zebrafish embryogenesis. Sequence analysis showed that the zebrafish Cyclin H and Cdk7 cDNAs encode proteins with 65% and 86% identity to the respective hu- man orthologs. RT-PCR and whole-mount in situ hybridization analyses of their expression in unfertilized eggs, embryos and organs of adult fish suggested that Cyclin H and Cdk7 messages are maternally loaded. Our data also showed that their transcripts were detected throughout development. Distribution of Cyclin H transcripts was found to be ubiquitous during early stages of development and become restricted to the anterior neural tube, brain, eyes, procreate tissues, liver and heart by 5 days post-fertilization. Expression of a dominant-negative form of Cyclin H delayed the onset of zygotic transcription in the early embryo, resulting in apoptosis at 5 hours post-fertilization and leading to sever defects in tis- sues normally exhibiting high levels of Cyclin H expression. These results implicate Cyclin H in the regulation of the transcriptional machinery during midblastula transition and suggest that it is an essential gene in early zebrafish larval development. 展开更多
关键词 ZEBRAFISH Cyclin H Cdk7 whole-mount in situ hybridization embryonic development midblastula transition
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Synthesis, characterization and application of a dispersant based on rosin for coal-water slurry 被引量:11
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作者 Li Junguo Zhang Guanghua +1 位作者 Shang Ting Zhu Junfeng 《International Journal of Mining Science and Technology》 SCIE EI 2014年第5期695-699,共5页
A rosin derivative and maleopimaric acid diethanolamide(MAD), was synthesized, characterized by FTIR and1 H NMR, and applied as dispersant for the coal-water slurry(CWS) prepared from Chinese Shenfu coal. The CWS appl... A rosin derivative and maleopimaric acid diethanolamide(MAD), was synthesized, characterized by FTIR and1 H NMR, and applied as dispersant for the coal-water slurry(CWS) prepared from Chinese Shenfu coal. The CWS application performance investigation shows that the MAD dispersant has better abilities in reducing CWS viscosity and stabilizing the slurry than a commercial dispersant—sulfonated naphthalene-formaldehyde condensate(SNF). The physicochemical property investigation of the two tested dispersants shows that the adsorption amount of the MAD at coal-water interface is much larger than that of SNF, and the MAD has better wetting property than the SNF on the coal surface. It indicated that the excellent capabilities of MAD are related to the adsorption mode of standing upright on the coal surface. Based on the above, the mechanism of dispersion and stabilization of the CWS prepared from MAD dispersant is presented. 展开更多
关键词 Rosin derivative Coal-water slurry Dispersant Adsorption
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Kinetic Treatment for Copolymerization of Styrene or Methyl Methacrylate with N-phenylmaleimide
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作者 单国荣 翁志学 +1 位作者 黄志明 潘祖仁 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2000年第1期1-5,共5页
Shirota's kinetic model and our kinetic model were used to treat the kinetic data of styrene (St) and N-phenylmaleimide (PMI) copolymerization in which charge-transfer complex (CTC) was formed. The results obtaine... Shirota's kinetic model and our kinetic model were used to treat the kinetic data of styrene (St) and N-phenylmaleimide (PMI) copolymerization in which charge-transfer complex (CTC) was formed. The results obtained by Shirota's kinetic model were disagreed with the experiments and the experimental phenomena could not be explained. The kinetic data of all feed fractions can be treated with our kinetic model, and the experimental phenomena can be explained from the propagation constants and reactivity ratios. Our kinetic model is also suitable for the kinetic data of methyl methacrylate (MMA) and PMI copolymerization in which CTC can not be formed. 展开更多
关键词 COPOLYMERIZATION kinetic model charge-transfer complex
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A novel synthesis of fluvoxamine maleate
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作者 WANG Jian-lin HU Yu-lai 《Journal of Chemistry and Chemical Engineering》 2009年第8期32-37,43,共7页
Fluvoxamine maleate is an excellent antidepressive drug. In the literatures, it was synthesized by the use of 4-(trifluoromethyl) aniline or 4-(trifluoromethyl) benzonitrile as starting materials and 5-methoxy-4'... Fluvoxamine maleate is an excellent antidepressive drug. In the literatures, it was synthesized by the use of 4-(trifluoromethyl) aniline or 4-(trifluoromethyl) benzonitrile as starting materials and 5-methoxy-4'-(trifluoromethyl-phenyl) valerophenone as a key intermediate. However, the methods in literatures have some disadvantages, such as the use of expensive materials, heavy pollution of environment, long reaction time and low yield of the product (only 30-40% overall yield). We herein report an environmentally friendly synthetic method of fluvoxamine maleate, which used 4-(trifluoromethyl) benzoic acid and tetrahydrofuran as starting materials and FeCI3 as catalyst for the coupling of acid chloride with Grignard reagent. The fluvoxamine maleate was synthesized in 46% overall yield, through the oximation, etheration and salification of the intermediate successively.This method has some advantages, such as the use of commercially available materials, low cost, short production period (12-14 h), high yield and light pollution. 展开更多
关键词 4-(trifluoromethyl) benzoic acid TETRAHYDROFURAN SYNTHESIS fluvoxamine maleate
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New records of bats from the northern region of the Peruvian Amazon
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作者 M Mónica Díaz 《Zoological Research》 CAS CSCD 北大核心 2011年第2期168-178,共11页
The northern Amazon Basin in Peru is one of the most diverse areas for small mammals in the world.In this work,I present information related to the diversity of bat species in the Amazonian region of Iquitos,Peru,wher... The northern Amazon Basin in Peru is one of the most diverse areas for small mammals in the world.In this work,I present information related to the diversity of bat species in the Amazonian region of Iquitos,Peru,where nearly 60%of the 152 bat species known to Peru recorded.Unlike in previous investigations in this area,bat surveys were designed to detect species living in urban and rural areas.The results have added a new bat species(Eumops delticus)to the Peruvian fauna,eight new species for the region around Iquitos(Peropteryx macrotis,Peropteryx pallidoptera,Anoura caudifer,Lionycteris spurrelli,Vampyrum spectrum,Thyroptera lavali,Cynomops planirostris,and Molossus coibensis),and a new species for Northeast Peru(Eumops maurus). 展开更多
关键词 CHIROPTERA Iquitos AMAZON CHECKLIST
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Effects of Co and Al addition on martensitic transformation and microstructure in ZrCu-based shape memory alloys
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作者 高卫红 孟祥龙 +1 位作者 蔡伟 赵连城 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第3期850-855,共6页
The effect of ternary alloying element Al and quaternary alloying element Co on the martensitic transformation of ZrCu-based shape memory alloy was investigated. The results show that the addition of Al and Co in ZrCu... The effect of ternary alloying element Al and quaternary alloying element Co on the martensitic transformation of ZrCu-based shape memory alloy was investigated. The results show that the addition of Al and Co in ZrCu alloy decreases both the martensitic transformation temperature and the martensitic transformation temperature hysteresis. Transmission electron microscope (TEM) observations reveal that theCm martensite structure is the preferential formation phase. The intervariant structures in ZrCuAlCo alloy are (021) type I twins, while the dominant substructures inside the martensite variant are the (001) compound twins. With the increase of Co content, tensile fracture strength and strain are improved obviously. 展开更多
关键词 ZrCu-based alloy shape memory alloy martensitic transformation MICROSTRUCTURE
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