Feldspar Pb isotopes have been widely used to trace magmatic formation and evolution processes.However,it remains unclear whether post-magmatic thermal events can affect feldspar Pb isotopic ratios.Here,the in situ Pb...Feldspar Pb isotopes have been widely used to trace magmatic formation and evolution processes.However,it remains unclear whether post-magmatic thermal events can affect feldspar Pb isotopic ratios.Here,the in situ Pb isotopic composition of feldspar hosted in granitic rocks(thirteen Archean and one Paleoproterozoic)from the northern Kongling terrane,Yangtze Craton,South China,is analyzed.The samples reveal a substantial variation in their Pb isotopic composition,spanning the gap between the 1.9 Ga and present-day geochrons,which indicates extensive resetting by later tectonothermal events.This resetting was interpreted to have likely resulted from Paleoproterozoic and Neoproterozoic tectonothermal events related to the assembly and breakup of the Columbia and Rodinia supercontinents.These results suggest that Pb isotopes should be used cautiously when tracing magma sources and petrogenesis in magmatic rocks that have experienced post-magmatic reworking.However,the in situ Pb isotopic composition of feldspar in ancient granitoids may also potentially be used to reveal later tectonothermal events.The extensive resetting of the Pb isotopic composition in feldspar by regional thermal events may also provide new insights into our understanding of the Pb isotope paradox.展开更多
Bacillus subtilis Bac01 was mutated by 15 keV N+ ions of 1.5×1016 cm-2. The mutant strain Bac11 with high yield of endoglucanase was isolated using carboxymethylcellulose sodium and congo red indicative plates. I...Bacillus subtilis Bac01 was mutated by 15 keV N+ ions of 1.5×1016 cm-2. The mutant strain Bac11 with high yield of endoglucanase was isolated using carboxymethylcellulose sodium and congo red indicative plates. It exhibited higher endoglucanase activitiy (381.89IU) than the original strain Bac01 (93.33IU). Two 1,500 bp endoglucanase gene fragments were obtained with PCR amplification from B. subtilis Bac01 and mutant strain Bac11. BLAST comparison result indicated that 10 nucleotides mutated. Bioinformatics methods were used to analyze the two predicted amino acid sequences, and it was found that 5 amino acid residues changed, being all in the cellulose-binding domain of endoglucanase.展开更多
As the key point in sex hormone analysis, sample pre-treatment technology has attracted scientists' attention all over the world, and the development trend of sample preparation forwarded to faster and more effici...As the key point in sex hormone analysis, sample pre-treatment technology has attracted scientists' attention all over the world, and the development trend of sample preparation forwarded to faster and more efficient technologies. Taking economic and environmental concerns into account, subcritical fluid extraction as a faster and more efficient method has stood out as a sample pre-treatment technology. This new extraction technology can overcome the shortcomings of supercritical fluid and achieve higher extraction efficiency at relatively low pressures and temperatures. In this experiment, a simple, sensitive and efficient method has been developed for the determination of diethylstilbestrol(DES) in fish tissue using subcritical 1,1,1,2-tetrafluoroethane(R134a) extraction in combination with gas chromatography-mass spectrometry(GC-MS). After extraction, freezing-lipid filtration was utilized to remove fatty co-extract. Further purification steps were performed with C_(18) and NH_2 solid phase extraction(SPE). Finally, the analyte was derived by heptafluorobutyric anhydride(HFBA), followed by GC-MS analysis. Response surface methodology(RSM) was employed to optimizing the extraction condition, and the optimized was as follows: extraction pressure, 4.3 MPa; extraction temperature, 26℃; amount of co-solvent volume, 4.7 m L. Under this condition, at a spiked level of 1, 5, 10 μg kg^(-1), the mean recovery of DES was more than 90% with relative standard deviations(RSDs) less than 10%. Finally, the developed method has been successfully used to analyzing the real samples.展开更多
据世界卫生组织估计,戊型肝炎病毒(hepatitis E virus,HEV)每年全球约有2000万例的新发感染,可能导致超过300万例急性肝炎。我国是戊型病毒性肝炎(戊肝)高流行区,近年来戊肝发病人数已超过甲型病毒性肝炎(甲肝)。戊肝发病率从2010年的1....据世界卫生组织估计,戊型肝炎病毒(hepatitis E virus,HEV)每年全球约有2000万例的新发感染,可能导致超过300万例急性肝炎。我国是戊型病毒性肝炎(戊肝)高流行区,近年来戊肝发病人数已超过甲型病毒性肝炎(甲肝)。戊肝发病率从2010年的1.77/10万上升至2019年的2.02/10万。我国HEV感染途径主要为食源性感染。慢性HEV感染是指患者感染HEV后,血或粪便中病毒核酸持续阳性3个月以上,其多发生于免疫低下人群,并可能导致患者出现肝纤维化和肝硬化的快速进展。我国以HEV 4型感染为主,因此我国慢性戊肝患者感染的病毒也主要为HEV 4型。HEV感染诊断主要依据特异性HEV抗体或病原学指标。HEV感染筛查应着重关注基础肝病患者、育龄期妇女和老年人及免疫缺陷患者(如器官移植患者、血液肿瘤患者、HIV感染者)等。戊肝诊治中仍然存在很多问题,包括慢性戊肝患者肝纤维化快速进展的危险因素尚未明确;老年男性和孕妇感染HEV后易出现重症的机制有待研究;抗HEV药物筛选多为体外细胞模型的结果,治疗药物仍处于临床前研究阶段。今后应聚焦戊肝的发病机制研究,推动基础研究和临床研究的交叉、融合与转化,为慢性戊肝诊治的药物治疗提供更多有效方案。展开更多
Biomass of seedlings at different developing stages of growth is important information for studying the response of species to site conditions.The objectives of this study was to explore the distribution characteristi...Biomass of seedlings at different developing stages of growth is important information for studying the response of species to site conditions.The objectives of this study was to explore the distribution characteristics of AGB(above-ground biomass)and BGB(below-ground biomass)of Abies georgei var.smithii seedlings of different ages,and investigate the effects of topography(slope aspect,altitude),plant community characteristics(crown density,species diversity,etc.),and soil properties(soil physical and chemical properties)on the biomass and its allocation.Seedlings in five age classes(1–2,3–4,5–6,7–8,and 9–10 years old)were collected by full excavation from 6 elevations(3800 m,3900 m,4000 m,4100 m,4200 m,4300 m)on the north and south slopes of Sejila Mountain in Tibet.15seedlings of each age class were investigated at one altitude.The individual effects of seedling age(SA)and the interaction effects of SA,slope aspect(SL),and elevation(EG),namely,SL×EG,SL×SA,EG×SA,and SL×EG×SA,had significant effects on the AGB of the seedlings(p<0.05),whereas BGB was only significantly affected by SA(p<0.001).The AGB and BGB of the seedlings showed a binomial growth trend with the increase in seedling age,and had an allometric relationship at different elevations,α(allometric exponential)varied from 0.913 to 1.046 in the northern slope,and from 1.004 to 1.268 in the southern slope.The biomass of seedlings on the northern slope was remarkably affected by stand factors,with a contribution rate of 47.8%,whereas that on the southern slope was considerably affected by soil factors with a contribution rate of 53.2%.The results showed that age was the most important factor affecting seedling biomass.The allometric pattern of seedling biomass was relatively stable,but in a highaltitude habitat,A.georgei var.smithii seedlings increased the input of BGB.Understanding seedling biomass allocation and its influencing factors is useful for evaluating plants’ability to acquire resources and survival strategies for adaptation to the environment in Tibet Plateau.展开更多
基金supported by the Key Laboratory of Gold Mineralization Processes and Resource Utilization,MNRShandong Provincial Key Laboratory of Metallogenic Geological Process and Resource Utilization(Grant No.KFKT202103)National Natural Science Foundation of China(Grant No.41876037)。
文摘Feldspar Pb isotopes have been widely used to trace magmatic formation and evolution processes.However,it remains unclear whether post-magmatic thermal events can affect feldspar Pb isotopic ratios.Here,the in situ Pb isotopic composition of feldspar hosted in granitic rocks(thirteen Archean and one Paleoproterozoic)from the northern Kongling terrane,Yangtze Craton,South China,is analyzed.The samples reveal a substantial variation in their Pb isotopic composition,spanning the gap between the 1.9 Ga and present-day geochrons,which indicates extensive resetting by later tectonothermal events.This resetting was interpreted to have likely resulted from Paleoproterozoic and Neoproterozoic tectonothermal events related to the assembly and breakup of the Columbia and Rodinia supercontinents.These results suggest that Pb isotopes should be used cautiously when tracing magma sources and petrogenesis in magmatic rocks that have experienced post-magmatic reworking.However,the in situ Pb isotopic composition of feldspar in ancient granitoids may also potentially be used to reveal later tectonothermal events.The extensive resetting of the Pb isotopic composition in feldspar by regional thermal events may also provide new insights into our understanding of the Pb isotope paradox.
基金Supported by the Natural Science Foundations of Xinjiang (No.2009211B06) Xinjiang University (No. QN070109)
文摘Bacillus subtilis Bac01 was mutated by 15 keV N+ ions of 1.5×1016 cm-2. The mutant strain Bac11 with high yield of endoglucanase was isolated using carboxymethylcellulose sodium and congo red indicative plates. It exhibited higher endoglucanase activitiy (381.89IU) than the original strain Bac01 (93.33IU). Two 1,500 bp endoglucanase gene fragments were obtained with PCR amplification from B. subtilis Bac01 and mutant strain Bac11. BLAST comparison result indicated that 10 nucleotides mutated. Bioinformatics methods were used to analyze the two predicted amino acid sequences, and it was found that 5 amino acid residues changed, being all in the cellulose-binding domain of endoglucanase.
基金supported by the National Natural Science Foundation of China (31071541)a program for Changjiang Scholars and Innovative Research Team in University (IRT1188)
文摘As the key point in sex hormone analysis, sample pre-treatment technology has attracted scientists' attention all over the world, and the development trend of sample preparation forwarded to faster and more efficient technologies. Taking economic and environmental concerns into account, subcritical fluid extraction as a faster and more efficient method has stood out as a sample pre-treatment technology. This new extraction technology can overcome the shortcomings of supercritical fluid and achieve higher extraction efficiency at relatively low pressures and temperatures. In this experiment, a simple, sensitive and efficient method has been developed for the determination of diethylstilbestrol(DES) in fish tissue using subcritical 1,1,1,2-tetrafluoroethane(R134a) extraction in combination with gas chromatography-mass spectrometry(GC-MS). After extraction, freezing-lipid filtration was utilized to remove fatty co-extract. Further purification steps were performed with C_(18) and NH_2 solid phase extraction(SPE). Finally, the analyte was derived by heptafluorobutyric anhydride(HFBA), followed by GC-MS analysis. Response surface methodology(RSM) was employed to optimizing the extraction condition, and the optimized was as follows: extraction pressure, 4.3 MPa; extraction temperature, 26℃; amount of co-solvent volume, 4.7 m L. Under this condition, at a spiked level of 1, 5, 10 μg kg^(-1), the mean recovery of DES was more than 90% with relative standard deviations(RSDs) less than 10%. Finally, the developed method has been successfully used to analyzing the real samples.
文摘据世界卫生组织估计,戊型肝炎病毒(hepatitis E virus,HEV)每年全球约有2000万例的新发感染,可能导致超过300万例急性肝炎。我国是戊型病毒性肝炎(戊肝)高流行区,近年来戊肝发病人数已超过甲型病毒性肝炎(甲肝)。戊肝发病率从2010年的1.77/10万上升至2019年的2.02/10万。我国HEV感染途径主要为食源性感染。慢性HEV感染是指患者感染HEV后,血或粪便中病毒核酸持续阳性3个月以上,其多发生于免疫低下人群,并可能导致患者出现肝纤维化和肝硬化的快速进展。我国以HEV 4型感染为主,因此我国慢性戊肝患者感染的病毒也主要为HEV 4型。HEV感染诊断主要依据特异性HEV抗体或病原学指标。HEV感染筛查应着重关注基础肝病患者、育龄期妇女和老年人及免疫缺陷患者(如器官移植患者、血液肿瘤患者、HIV感染者)等。戊肝诊治中仍然存在很多问题,包括慢性戊肝患者肝纤维化快速进展的危险因素尚未明确;老年男性和孕妇感染HEV后易出现重症的机制有待研究;抗HEV药物筛选多为体外细胞模型的结果,治疗药物仍处于临床前研究阶段。今后应聚焦戊肝的发病机制研究,推动基础研究和临床研究的交叉、融合与转化,为慢性戊肝诊治的药物治疗提供更多有效方案。
基金supported by the National Natural Science Foundation of China(Grant No.31960256)Graduate Innovation Program of Key Laboratory of Forest Ecology in Tibet Plateau,Ministry of Education(XZA-JYBSYS-2021-Y13)+1 种基金the Central Government Guides Local Science and Technology Development Projects,China(XZ202101YD0016C)the Independent Research Project of Science and Technology Innovation Base in Tibet Autonomous Region(XZ2022JR0007G)。
文摘Biomass of seedlings at different developing stages of growth is important information for studying the response of species to site conditions.The objectives of this study was to explore the distribution characteristics of AGB(above-ground biomass)and BGB(below-ground biomass)of Abies georgei var.smithii seedlings of different ages,and investigate the effects of topography(slope aspect,altitude),plant community characteristics(crown density,species diversity,etc.),and soil properties(soil physical and chemical properties)on the biomass and its allocation.Seedlings in five age classes(1–2,3–4,5–6,7–8,and 9–10 years old)were collected by full excavation from 6 elevations(3800 m,3900 m,4000 m,4100 m,4200 m,4300 m)on the north and south slopes of Sejila Mountain in Tibet.15seedlings of each age class were investigated at one altitude.The individual effects of seedling age(SA)and the interaction effects of SA,slope aspect(SL),and elevation(EG),namely,SL×EG,SL×SA,EG×SA,and SL×EG×SA,had significant effects on the AGB of the seedlings(p<0.05),whereas BGB was only significantly affected by SA(p<0.001).The AGB and BGB of the seedlings showed a binomial growth trend with the increase in seedling age,and had an allometric relationship at different elevations,α(allometric exponential)varied from 0.913 to 1.046 in the northern slope,and from 1.004 to 1.268 in the southern slope.The biomass of seedlings on the northern slope was remarkably affected by stand factors,with a contribution rate of 47.8%,whereas that on the southern slope was considerably affected by soil factors with a contribution rate of 53.2%.The results showed that age was the most important factor affecting seedling biomass.The allometric pattern of seedling biomass was relatively stable,but in a highaltitude habitat,A.georgei var.smithii seedlings increased the input of BGB.Understanding seedling biomass allocation and its influencing factors is useful for evaluating plants’ability to acquire resources and survival strategies for adaptation to the environment in Tibet Plateau.
