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| 1 | Soil pH impact on microbial tetraether lipids and terrestrial input index (BIT) in China显示文摘The distributions of microbial tetraether lipids i.e. glycerol dialkyl glycerol tetraethers (GDGTs) were investigated in a variety of Chinese soils featured by a wide range of pH values in different climate zones. The bacterial branched GDGTs and archaeal isoprenoid GDGTs were found to be widely distributed in Chinese soils and their relative abundance was controlled primarily by soil pH. The bacterial bGDGTs usually dominate over archaeal iGDGTs in abundance when the soil pH is below 8.0. However archaeal iGDGTs become dominant and the abundance of halophilic archaea characterized by GDGT V without cyclopentyl ring increases dramatically in the alkaline soil with pH greater than 8.0. The relative abundance of archaeal iGDGTs to bacterial bGDGTs was defined here as RAI index. The RAI index decreases with elevated soil pH and a linear correlation is found between them indicating that the relative abundance of archaeal iGDGTs to bacterial bGDGTs increases with increased pH. The RAI index thus could be a novel proxy of the pH values of paleosol. The terrestrial input index BIT (Branched and Isoprenoid Tetraethers Index) decreases with increased soil pH suggesting that soil pH should be taken into consideration when the terrestrial contribution to marine sediments is estimated by BIT index. Moreover the TEX86 index cannot be used to reconstruct sea surface temperature in the sediments featured by a large terrestrial input. | YANG Huan DING WeiHua WANG JinXiang JIN ChengSheng HE GangQiang QIN YangMin XIE ShuCheng | 2012 | Science China Earth Sciences2012，55，2： | 19 |
| 2 | Peat molecular fossils recording paleoclimatic change and organism replacement显示文摘The occurrence of the dominant C23 n-alkane derived from bryophyte was demonstrated to be related to the cold climate, based on the GC and GC/MS analyses on a 40-cm long peat core, in which this compound exponentially varies in abundance with the depth corresponding to the well-known second Little Ice Age. Both the variation of the chemical components of modern bryophyte resulted from climatic change and the ecological data about the biological growth influenced by climate shed light on the point that the variation of this compound in the peat was related to the cold climate. This was also evidenced by the previously-reported lacustrine data. In addition, the variations of the ratios of ketones/esters and C24 n-alkene/n-alkane (C24:1/024:0) display the trend identical with that of organisms, implicating the replacement between bryophyte and monocotyledon occurring in the peat core. | XIE Shucheng & R. P. Evershed1. Faculty of Earth Science, China University of Geosciences, Wuhan 430074, China 2. School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK Correspondence should be addressed to Xie Shucheng (e-mail: scxie@ public.wh.hb.cn) | 2001 | Chinese Science Bulletin2001，46，20： | 16 |
| 3 | Nitric Oxide Reduces Hydrogen Peroxide Accumulation Involved in Water Stress-induced Subcellular Anti-oxidant Defense in Maize Plants显示文摘Nitric oxide (NO) is a bioactive molecule involved in many biological events, and has been reported as pro-oxidant as well as anti-oxidant in plants. In the present study, the sources of NO production under water stress, the role of NO in water stress-induced hydrogen peroxide (H2O2) accumulation and subcellular activities of anti-oxidant enzymes in leaves of maize (Zea mays L.) plants were investigated. Water stress induced defense increases in the generation of NO in maize mesphyll cells and the activity of nitric oxide synthase (NOS) in the cytosolic and microsomal fractions of maize leaves. Water stress-induced defense increases in the production of NO were blocked by pretreatments with inhibitors of NOS and nitrate reductase (NR), suggesting that NO is produced from NOS and NR in leaves of maize plants exposed to water stress. Water stress also induced increases in the activities of the chloroplastic and cytosolic anti-oxidant enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR), and the increases in the activities of anti-oxidant enzymes were reduced by pretreatments with inhibitors of NOS and NR. Exogenous NO increases the activities of water stress-induced subcellular anti-oxidant enzymes, which decreases accumulation of H2O2. Our results suggest that NOS and NR are involved in water stress-induced NO production and NOS is the major source of NO. The potential ability of NO to scavenge H2O2 is, at least in part, due to the induction of a subcellular anti-oxidant defense. | Jianrong Sang Mingyi Jiang Fan Lin Shucheng Xu Aying Zhang Mingpu Tan | 2008 | Journal of Integrative Plant Biology2008，50，2： | 15 |
| 4 | Spurious Thermoluminescence Characteristics of the Ediacaran Doushantuo Formation(ca. 635–551 Ma) and Its Implications for Marine Dissolved Organic Carbon Reservoir显示文摘The Ediacaran Doushantuo Formation(ca. 635–551 Ma) deposited immediately after the last Neoproterozoic glaciations and recorded the most prominent negative excursions of carbonate carbon isotopic composition(δ^(13)C_(carb)). These excursions have been interpreted as a result of widespread remineralization of a large dissolved organic carbon(DOC) reservoir in the Ediacaran deep oceans. However, there is no direct evidence so far found in rocks for the proposed DOC reservoir, which devalues such an interpretation. Here, we conducted a detailed study on the glow-curves characteristics and signal origins of spurious thermoluminescence(TL) of the Doushantuo Formation at Jiulongwan in Yangtze Gorges area, South China, through sequential tests under CO_2, N_2 and air. Spurious TL intensities for test samples before and after removing soluble organic matter via accelerated solvent extraction(ASE) are nearly identical. Further, significant positive correlation between the spurious TL intensity and total inorganic carbon(TIC) content(R^2=0.7) indicate that the Doushantuo spurious TL with the characteristic peak at 393.5 °C from the sequential test is chemiluminescence(CL) which is derived from the oxidation of a type of non-volatile organic matter strongly associated with carbonate mineral lattice(termed as 'X-OM'). A most likely explanation is that the X-OM is a type of dissolved organic matter which co-precipitated with carbonate minerals into sediments in the Ediacaran Doushantuo Ocean. Furthermore, a significant exponential negative correlation(R^2=0.55) is observed between the CL data and the isotopic difference between carbonate and coexisting bulk organic matter(i.e., Δ^(13)C_(carb-org), a proxy for remineralization degree of DOC reservoir in proposed DOC hypothesis), suggesting that the X-OM was derived from the oxidation of the DOC reservoir in the Ediacaran Ocean. We thus propose that the X-OM and its CL detected in our study may have recorded the evolution of the possible DOC reservoir in the Ediacaran Doushantuo Ocean. If this is correct, the stratigraphic variations of the CL intensity in the Doushantuo Formation at Jiulongwan support the pulsed oxidation of the DOC reservoir in the Ediacaran Ocean. Our findings indicate that the CL derived from the oxidation of non-volatile organic matter which is strongly associated with carbonate mineral lattices in rocks may provide a feasible approach for probing the evolution of DOC reservoir in the ancient oceans, thus likely provide direct geological evidence for the development of oceanic DOC reservoir in geological times. | Haiyang Wang Chao Li Chaoyong Hu Shucheng Xie | 2015 | Journal of Earth Science2015，26，6： | 12 |
| 5 | A theoretical prediction of chemical zonation in early oceans(>520 Ma)显示文摘Early oceans(>520 Ma) were characterized by widespread water-column anoxia, stratification, and limited oxidant availability, which are comparable to the chemical characteristics of modern marine sedimentary pore-waters in productive continental margins. Based on this similarity and our current understanding of the formation mechanism of early Earth ocean chemistry, we propose an idealized chemical zonation model for early oceans that includes the following redox zones(from shallow nearshore to deep offshore regions): oxic, nitrogenous(NO3?-NO2?-enriched), manganous-ferruginous(Mn2+ or Fe2+-enriched), sulfidic(H2S-enriched), methanic(CH4-enriched), and ferruginous(Fe2+-enriched). These zones were dynamically maintained by a combination of processes including surface-water oxygenation by atmospheric free oxygen, nitrate reduction beneath the chemocline, nearshore manganese-iron reduction, sulfate reduction, methanogenesis, and hydrothermal Fe2+ inputs from the deep ocean. Our modified 'euxinic wedge' model expands on previous versions of this model, providing a more complete theoretical framework for the chemical zonation of early Earth oceans that helps to explain observations of unusual Mo-S-C isotope patterns. This model may provide a useful foundation for future studies of ocean chemistry evolution and elemental biogeochemical cycles in early Earth history. | LI Chao CHENG Meng Thomas J.ALGEO XIE ShuCheng | 2015 | Science China Earth Sciences2015，58，11： | 11 |
| 6 | Geomicrobial functional groups:A window on the interaction between life and environments显示文摘Microbes are well-known for their great diversity and abundance in modern natural environments.They also are believed to pro-vide critical links among higher organisms and their associated environments.However,the low diversity of morphological fea-tures and structures of ancient microbes preserved in sediments and rocks make them difficult to identify and classify.This diffi-culty greatly hinders the investigation of geomicrobes throughout Earth history.Thus,most previous paleontological studies have focused on faunal and floral fossils.Here,geomicrobial functional groups(GFGs),or a collection of microbes featured in specific ecological,physiological or biogeochemical functions,are suggested to provide a way to overcome the difficulties of ancient mi-crobe investigations.GFGs are known for their great diversity in ecological,physiological and biogeochemical functions.In addi-tion,GFGs may be preserved as the biogeochemical,mineralogical and sedimentological records in sediments and rocks.We reviewed the functions,origins and identification diagnostics of some important GFGs involved in the elemental cycles of carbon,sulfur,nitrogen and iron.GFGs were further discussed with respect to their significant impacts on paleoclimate,sulfur chemistry of ancient seawater,nutritional status of geological environments,and the deposition of Precambrian banded iron formations. | XIE ShuCheng YANG Huan LUO GenMing HUANG XianYu LIU Deng WANG YongBiao GONG YiMing XU Rana | 2012 | Chinese Science Bulletin2012，57，1： | 11 |
| 7 | Discussion on geobiology, biogeology and geobiofacies显示文摘Here we first discuss the definition of and the difference between geobiology and biogeology following a brief introduction of recent geobiology research in China. Geobiology is defined as an interdisciplinary study of life sciences and earth sciences, and biogeology as an interdisciplinary study of biology and geology. Scope of the term geobiology covers that of the term biogeology. Branch interdisciplines of both are listed. We then propose the term geobiofacies, defined as the facies of a geologic body embodying the whole process of interaction between organisms and environments. Differences among geobiofacies, biofacies, and organic facies are discussed. Main parameters defining a geobiofacies include habitat type, biotic composition and productivity, paleo-oxygenation regimes, and early diagenesis phases. Each of them is discussed in detail, and a semi-quantitative assessment of the biogeofacies of source rocks is proposed based on these parameters. A two-fold terminology for geobiofacies is recommended, namely, the biological and environmental aspects of biota and the redox conditions during life-burial-diagenesis | YIN HongFu XIE ShuCheng QING JianZhong YAN JiaXin LUO GenMing | 2008 | Science China Earth Sciences2008，51，11： | 11 |
| 8 | Progress and perspective on frontiers of geobiology显示文摘Geobiology is a new discipline on the crossing interface between earth science and life science,and aims to understand the interaction and co-evolution between organisms and environments.On the basis of the latest international achievements,the new data presented in the Beijing geobiology forum sponsored by Chinese Academy of Sciences in 2013,and the papers in this special issue,here we present an overview of the progress and perspectives on three important frontiers,including geobiology of the critical periods in Earth history,geomicrobes and their responses and feedbacks to global environmental changes,and geobiology in extreme environments.Knowledge is greatly improved about the close relationship of some significant biotic events such as origin,radiation,extinction,and recovery of organisms with the deep Earth processes and the resultant environmental processes among oceans,land,and atmosphere in the critical periods,although the specific dynamics of the co-evolution between ancient life and paleoenvironments is still largely unknown.A variety of geomicrobial functional groups were found to respond sensitively to paleoenvironmental changes,which enable the establishment of proxies for paleoenvironmental reconstruction,and to play active roles on the Earth environmental changes via elemental biogeochemical cycles and mineral bio-transformations,but to be deciphered are the mechanisms of these functional groups that change paleoenvironmental conditions.Microbes of potential geobiology significance were found and isolated from some extreme environments with their biological properties partly understood,but little is known about their geobiological functions to change Earth environments.The biotic processes to alter or modify the environments are thus proposed to be the very issue geobiology aims to decipher in the future.Geobiology will greatly extend the temporal and spatial scope of biotic research on Earth and beyond.It has great potential of application in the domains of resource exploration and global change.To achieve these aims needs coordinative multidisciplinary studies concerning geomicrobiology and related themes,database and modeling of biogeochemical cycles,typical geological environments,and coupling of biological,physical,and chemical processes. | XIE ShuCheng YIN HongFu | 2014 | Science China Earth Sciences2014，57，5： | 10 |
| 9 | Holocene vegetation cover in Qin’an area of western Chinese Loess Plateau revealed by n-alkane显示文摘Previous studies have found that wetlands prevailed in western Chinese Loess Plateau and pine pollen could reach up to 80% in Qin’an area of the plateau during middle Holocene. It was then deduced that forest vegetation covered Qin’an area in a warm and wet climate during middle Holocene. The proxies of molecule biomarkers from two Holocene sections, a swamp-alluvial loess section and a typical loess-paleosol section are used to reconstruct regional vegetation history. It is found that the heavy-molecular-weight (HMW) homologues of the n-alkanes in all samples exhibit a pronounced odd-over-even predominance, maximizing at C31 and the abundance of the nC27-alkanes is the lowest in nC27, nC29, nC31, i.e. C27 | ZHONG YanXia CHEN FaHu AN ChengBang XIE ShuCheng HUANG XianYu | 2007 | Chinese Science Bulletin2007，52，12： | 10 |
| 10 | Characterstics of seasonal variations of leaf n-alkanesand n-alkenes in modern higher plants in Qingjiang, Hubei Province, China显示文摘On the basis of GC and GC-MS analyses, the seasonal variation of leaf lipids is observed in five plant species in Qingjiang in Hubei Province. The CPI values (carbon preference index) of n-alkanes decrease gradually from May to November, though the carbon number distributions and the predominant carbon number in an individual species keep unchanged. The declined CPI values might be caused by the leaf fading, which is further supported by a comparison of the defoliated leaves with the fresh leaves. This observation infers the CPI values of n-alkanes in Quaternary sediments can be used as a tool to index the humification, and thus the climatic and the environmental conditions. The plants analyzed here show a remarkable difference in n-alkanes abundance, suggesting their differential contribution to the n-alkanes identified in sediments. The abundance and the compound species of the n-alkenes detected in the plant leaves change greatly with the seasons due to the influence of temperature, with the least compounds being identified in August. | CUI JingWei HUANG JunHua XIE ShuCheng | 2008 | Chinese Science Bulletin2008，53，17： | 10 |
| 11 | The fluctuating environment associated with the episodic biotic crisis during the Permo/Triassic transition:Evidence from microbial biomarkers in Changxing,Zhejiang Province显示文摘The environmental conditions and the biotic crisis during the Permo-Triassic (Tr/P) transition received increasing attention in the past decades. Presented herein are the molecular fossil records of cyano-bacteria and green sulfur bacteria,the base of the marine ecosystem,to highlight the episodic nature of both the environment and the biotic crisis during this critical period. At least two episodes of cyano-bacterial expansion are documented by 2-methylhopanes ranging from C28 to C32 in carbon number,indicative of the instable marine ecosystem and the fluctuant aquatic nutrients. Meanwhile,the index of 2-alkyl-1,3,4-trimethylbenzenes (biomarkers of green sulfur bacteria) and the ratio of pristane to phy-tane (Pr/Ph) witness the fluctuation of sedimentary environmental redox conditions. The above mo-lecular evidence suggests the occurrence of highly fluctuating environmental conditions during the Tr/P transition,which is consistent with,and probably the cause of,the multi-phased biotic crisis and the prolonged faunal recovery. | HUANG XianYu JIAO Dan LU LiQiang XIE ShuCheng HUANG JunHua WANG YongBiao YIN HongFu WANG HongMei ZHANG KeXin LAI XuLong | 2007 | Science China Earth Sciences2007，50，7： | 10 |
| 12 | Environmental impacts on the distribution of microbial tetraether lipids in Chinese lakes with contrasting pH: Implications for lacustrine paleoenvironmental reconstructions显示文摘Glycerol dialkyl glycerol tetraethers(GDGTs) in lake sediments are useful biomarkers for the continental paleoclimatic reconstruction. However, the environmental controls on the distribution of these compounds, in particular the 6-methyl isomers of bacterial branched GDGTs(bGDGTs), in the lakes with contrasting pH, are still unknown, hindering their application for paleo-reconstructions. Here, we investigated the environmental impacts on the distribution of GDGTs in 17 alkaline lakes and 1 acid lake in China. It was found that the dissolved oxygen content in water column may have an impact on the distribution of archaeal isoprenoid GDGTs(iGDGTs) by causing the change in archaeal communities. The ratio of GDGT-0/crenarchaeol increases with decreasing oxygen content, indicating that the relative abundance of anaerobic methanogenic archaea or Miscellaneous Crenarchaeotic Group(MCG) vs. aerobic Thaumarchaeota is controlled by the oxygen content dissolved in water of these lakes. Thaumarchaeota are likely to contribute only a small proportion of iGDGTs in the relatively oxygen-depleted lakes, and thus TEX_(86) is not suitable for the reconstruction of the surface temperature of these lakes. The abundance ratio of iGDGTs to bGDGTs(R_(i/b)) appears to show no relationship with water pH in all the lakes, but exhibits a significant positive correlation with the water depth of the acid Lake Qinghai in Tengchong. As expected, the methylation degree of bGDGTs(MBT′) was found to correlate with both mean annual air temperature(MAT) and water pH, and the cyclization degree of bGDGTs(CBT) correlates only with water pH in these lakes. However, the MBT′_(5ME), an index to measure the methylation degree of 5-methyl bGDGTs, exhibits no relationship with MAT, whereas MBT′_(6ME), the methylation degree of 6-methyl bGDGTs, was found to correlate significantly with MAT. This is opposite to the situation observed in the global soils, pointing to a different adaptation of b GDGT-producing bacteria to environmental variables or different microbial sources of bGDGTs in these lakes. The relative abundance of 6- vs. 5-methyl bGDGTs is controlled by pH in these lakes, similar to that observed in worldwide soils. Hence, the isomer ratio(IR) of 6-methyl bGDGTs or CBT′ can be used as a proxy for water pH, although they might be influenced by other environmental factors including temperature in the lakes with a narrow range of pH. | DANG XinYue XUE JianTao YANG Huan XIE ShuCheng | 2016 | Science China Earth Sciences2016，59，5： | 9 |
| 13 | Role of brain-derived neurotrophic factor and neuronal nitric oxide synthase in stress-induced depression显示文摘BACKGROUND: Accumulated evidence indicates an important role for hippocampal dendrite atrophy in development of depression, while brain-derived neurotrophic factor (BDNF) participates in hippocampal dendrite growth. OBJECTIVE: To discuss the role of BDNF and neuronal nitric oxide synthase (nNOS) in chronic and unpredictable stress-induced depression and the pathogenesis of depression. DESIGN, TIME AND SETTING: Randomized, controlled animal experiment. The experiment was carried out from October 2006 to May 2007 at the Department of Animal Physiology, College of Life Science, Shaanxi Normal University. MATERIALS: Thirty-seven male Sprague-Dawley rats weighing 250-300 g at the beginning of the experiment were obtained from Shaanxi Provincial Institute of Traditional Chinese Medicine (Xi'an, China). BDNF antibody and nNOS antibody were provided by Santa Cruz (USA). K252a (BDNF inhibitor) and 7-NI (nNOS inhibitor) were provided by Sigma (USA). METHODS: Animals were randomly divided into five groups: Control group, chronic unpredicted mild stress (CUMS) group, K252a group, K252a+7-NI group and 7-NI+CUMS group. While the Control, K252a and K252a+7-NI groups of rats not subjected to stress had free access to food and water, other groups of rats were subjected to nine stressors randomly applied for 21 days, with each stressor applied 2-3 times. On days 1, 7, 14 and 21 during CUMS, rats received microinjection of 1 μL of physiological saline in the Control and CUMS groups, 1 μL of K252a in the K252a group, 1 μL of K252a and 7-NI in the K252a+7-NI group, and 1 μL of 7-NI in the 7-NI+CUMS group. We observed a variety of alterations in sucrose preference, body weight change, open field test and forced swimming test, and observed the expression of BDNF and nNOS in rat hippocampus by immunohistochemistry; MAIN OUTCOME MEASURES: ① A variety of behavioral alterations of rats; ② The expression of BDNF and nNOS in rat hippocampus. RESULTS: Compared with the Control group, the behavior of the CUMS rats was significantly depressed, the expression of BDNF decreased (P < 0.01) but the expression of nNOS increased (P < 0.01). The behavior of rats given intra-hippocampal injection of BDNF inhibitor was significantly depressed and the expression of nNOS was significantly increased (P < 0.01). Intra-hippocampal injections of an nNOS inhibitor reversed the depression-like behavioral changes induced by CUMS or intra-hippocampal injection of BDNF inhibitor. CONCLUSION: CUMS induced a decrease in expression of BDNF and an increase in expression of NO in the hippocampus, which may lead to depression. | Dan Wang Shucheng An | 2008 | Neural Regeneration Research2008，3，4： | 8 |
| 14 | Distribution of microbial fatty acids and fatty alcohols in soils from an altitude transect of Mt. Jianfengling in Hainan, China: Implication for paleoaltimetry and paleotemperature reconstruction显示文摘The temperature gradient along the altitude transect of Mt.Jianfengling provides a good opportunity to establish and evaluate the microbial lipid-based environmental proxies.The soils collected from 14 different altitudes of Mt.Jianfengling contain abundant microbial fatty acids and fatty alcohols,including iso/anteiso fatty acids(i/aC12:0–i/aC19:0),10-Me-C16:0 fatty acid,iso/anteiso fatty alcohols(i/aC13–iC26),10-Me-C16:0 fatty alcohol and unsaturated fatty alcohols,which can indicate a strong microbial activity in the Jianfengling soils.The branched and unsaturated fatty alcohols can be only detected when saponification is performed,implying that these lipids are present as the constituents of bacterial wax esters in the soils.The ratio of aC15/iC15 fatty acids is positively correlated with altitude,suggesting that the decrease in temperature can induce the increase in the relative abundance of anteiso C15 fatty acid.In contrast,the ratio of aC15/iC15 fatty alcohols and of aC15/nC15 fatty alcohols both decrease with increased altitude or decreased temperature.Similarly,the ratio of nC18:1/nC18:0 fatty alcohols also decreases with decreased temperature,which is opposite to the previous observation that unsaturation of fatty acids in microorganism increases in response to decreased temperature.Besides,the average chain length(ACL)of long chain fatty alcohols(C22–C30)from leaf waxes and carbon preference index(CPI)of all n-fatty alcohols are also significantly correlated with altitude or mean annual temperature,demonstrating their potential for paleoclimate reconstruction.The correlation of microbial fatty acids and alcohols as well as ACL and CPI of plant wax-derived fatty alcohols with altitude may provide novel ways to reconstruct paleotemperature and paleoaltimetry. | YANG Huan DING WeiHua XIE ShuCheng | 2014 | Science China Earth Sciences2014，57，5： | 8 |
| 15 | Geobiological approach to evaluating marine carbonate source rocks of hydrocarbon显示文摘Evaluating the pre-Jurassic marine source rocks in China has been difficult because these rocks are generally too highor over-maturated for most traditional methods to work.As to the remaining parameter TOC (%),its lower limit for recognizing the carbonate source rocks in China has been in dispute.Nineteen Phanerozoic sections in the Middle-Upper Yangtze Platform and the Guizhou-Hunan-Guangxi Basin have been studied in search for a different approach to complementing the traditional evaluation method for these source rocks.We have applied a geobiological approach to tracing the organic carbon (OC) output and accumulation from the living stage (primary productivity) to the post-mortem deposited remains,and finally to the preserved burial organics.Four biological and geological parameters are employed to represent the OC of the three stages.A series of proxies of these parameters are discussed and integrated to establish a geobiological evaluation system independent of TOC and other traditional methods.Here we use the Guangyuan section in Sichuan as an example for the geobiological evaluation.Our results indicate that in the argillaceous rocks,the geobiological parameters show the qualified source rocks in accordance with high TOC values;but in the carbonates,the good source rocks delineated by the geobiological parameters have a wide range of TOC,from 0.03% to 1.59%,mostly<0.3%.We suggest that it is still premature to set TOC=0.3% or 0.5% as the lower limit for the pre-Jurassic carbonate source rocks in South China. | YIN HongFu XIE ShuCheng YAN JiaXin HU ChaoYong HUANG JunHua Tenger QIE WenKun QIU Xuan | 2011 | Science China Earth Sciences2011，54，8： | 7 |
| 16 | Comparison of paleotemperature reconstructions using microbial tetraether thermometers of the Chinese loess-paleosol sequence for the past 350000 years显示文摘The recently proposed global and local calibrations for the mean annual air temperature(MAT) reconstruction on the basis of 5-and 6-methyl brGDGTs have rarely been applied to the Chinese LPS yet, leaving the applicability of these calibrations unclear. Here, we used the improved chromatography method to analyze 198 loess-paleosol samples from the Weinan section in the southern CLP for the past 350 kyr. The 6-methyl brGDGTs comprise a major proportion of total brGDGTs, pointing to alkaline conditions for most soil samples from the Weinan LPS. The decoupled profile variation of MBT′6ME and MBT′_(5ME) suggests their response to different enviromental factors, possibly soil pH(or soil moisture) and temperature, respectively. This discrimination further corraborates that temperature and monsoonal precipitation were not in phase during the last four deglaciations on the CLP. Temperature estimates for the six calibrations tested show similar trends but remarkably differ in amplitudes. The soil moisture appears to affect the global MBT′/CBT calibration, the global MATmr calibration(a calibration based on the multiple linear regression) and the Chinese local SSM(Stepwise Selection Method) calibration, resulting in a significant underestimation of late Holocene temperature. In contrast, the dry climate has no effect on the global MBT′5ME calibration. Of the six calibrations,only the Chinese local SSM calibration and global MATmr calibration produce temperature variation amplitude over the past 350 ka that is consistent with other independent proxy data. The recently proposed local calibrations based on 5-and 6-methyl brGDGTs for North China yield the amplitude of temperature changes that is much larger than the results determined by other approaches.All the six calibrations have their own weakness in the MAT reconstruction, due partly to the inconsistency between the brGDGT distribution in the Weinan LPS and the modern soils used to establish these calibrations. | TANG ChangYan YANG Huan DANG XinYue XIE ShuCheng | 2017 | Science China Earth Sciences2017，60，6： | 7 |
| 17 | Dielectric barrier plasma dynamics for active aerodynamic flow control显示文摘The paper investigates the dynamics of a new multiple bipolar multiple Dielectric Barrier Discharges(DBD)actuator using in large-scale flow control.Particle image velocimetry experiments are performed to characteristic the effectiveness of the multiple bipolar DBD plasma actuator.The results show that the mutual interaction between the electrodes,one major disadvantage of traditional DBD characterized by reverse discharge can be entirely avoided,and a constantly accelerating electric wind velocity can be obtained by using the new multiple bipolar DBD plasma actuator. | HAO JiangNan TIAN BaLin WANG YuLin SONG YaHui PAN ShuCheng LI WenFeng | 2014 | Science China(Physics,Mechanics & Astronomy)2014，57，2： | 6 |
| 18 | Effect of wastewater composition on the calcium carbonate precipitation in upflow anaerobic sludge blanket reactors显示文摘Calcium carbonate often precipitates in anaerobic reactors treating wastewater with high calcium content.The aim of this paper is to study the effect of wastewater composition on calcium carbonate precipitation in upflow anaerobic sludge blanket(UASB)reactors.Two laboratory-scale UASB reactors were operated with calcium-containing influents using acetate and carbohydrate as substrate,respectively.There was an obvious accumulation of inorganic precipitate observed in the biogranules.Observations via scanning electron microscope(SEM)and energy dispersive spectroscopy(EDS)showed that the acclimated biogranules in the two reactors differed in microstructure.Calcium carbonate was found to have precipitated on the surface of acetate-degrading biogranules,but precipitated at the core of the carbohydrate-degrading biogranules.The results indicated that substrates had significant influence on the location of calcium carbonate precipitation in anaerobic granular sludge,which was expected due to the different methanogens distribution and pH gradient within the granular sludge degrading various substrates.Moreover,the location of calcium carbonate precipitation substantially affected the specific methanogenic activity(SMA)of the granular sludge.The SMA of the acetate-degrading biogranules dropped from 1.96 gCODCH4·gVSS^(–1)·d^(–1)to 0.61 gCODCH4·gVSS^(–1)·d^(–1)after 180-d of operation in the reactor.However,the SMA of the carbohydrate-degrading biogranules was not adversely affected by calcium carbonate precipitation. | Shucheng YANG Yanling HE Yonghong LIU Charles CHOU Pengxiang ZHANG Dongqi WANG | 2010 | Frontiers of Environmental Science & Engineering2010，4，2： | 6 |
| 19 | Microbial and molecular fossils from the Permian Zoophycos in South China显示文摘The trace fossil Zoophycos was enriched in the lower part of the Guadalupian Maokou Formation of Permian in Laibin, Guangxi of South China, and characterized by observable lamellae within its spreiten. Associated with these lamellae are the prolific coccus- and spirillum-shaped microbe fossils. These microbes morphologically identified are 0.4―3.0 μm in diameter or length. Molecular fossils, including normal alkanes (dominated by C18, without an odd-over-even predominance), acyclic isoprenoids (such as pristane (Pr) and phytane (Ph)), extended tricyclic terpanes, pentacyclic triterpanes, steranes, al-kylcyclohexanes, dibenzothiophenes, benzonaphthothiophenes, benzobisbenzothiophenes, were in-strumentally identified in the wackestone characterized by the occurrence of abundant Zoophycos (composite ichnofabric indices are 4) and crowded microbial fossils. The value of the Pr/Ph ratio is less than 1, indicative of a dysoxic condition. The identification of abundant sulfur compounds (the thio-phene series) related to the contribution of reductive sulfur favors the occurrence of sulphate-reducing bacteria. The association of abundant microbial colonies with microbial molecular fossils within the spreiten suggests that trace fossils Zoophycos would be a multifunctional garden carefully constructed by the Zoophycos-producer, where different microbial colonies were orderly and carefully planted and cultured in different minor lamellae within spreiten. Hence, it is proposed that the Zoophycos-producer symbiosed with microbial colonies on the mutual basis of food supply and the redox conditions. | GONG YiMing XU Ran XIE ShuCheng HUANG XianYu HU Bin QI YongAn ZHANG GuoCheng | 2007 | Science China Earth Sciences2007，50，8： | 6 |
| 20 | Determination of PCDD/Fs and dioxin-like PCBs in food and feed using gas chromatography-triple quadrupole mass spectrometry显示文摘A method was developed on a gas chromatograph coupled to a triple quadrupole mass spectrometer(GC-MS/MS) for trace level determination of polychlorinated dibenzo-p-dioxins/dibenzofurans(PCDD/Fs) and dioxin-like polychlorinated biphenyls(DL-PCBs) in food and feed. The results demonstrated good sensitivity and repeatability for PCDD/Fs and DL-PCBs at an extremely low level(10 pg mL^(-1) for 2,3,7,8-TCDD/F), as well as wide linear response of over 3 or 4 orders of magnitude in concentration ranges; 0.5–200 ng mL^(-1) for PeCDD/F and 0.2–2000 ng mL^(-1) for DL-PCBs. The method detection limits for PCDD/Fs and DL-PCBs were in the range from 0.018–0.17 pg g^(-1) to 0.13–0.36 pg g^(-1), respectively. The performance of the GC-MS/MS for food and feed sample analysis showed high precision and accuracy compared to the high resolution gas chromatograph/high resolution mass spectrometer. The results indicated the feasibility of GC-MS/MS as a confirmatory method for the measurement of PCDD/Fs and DL-PCBs in food and feed as required by European Union legislation. | Huizhong Sun Pu Wang Honghua Li Yingming Li Shucheng Zheng Julius Matsiko Yanfen Hao Weiwei Zhang Dou Wang Qinghua Zhang | 2017 | Science China Chemistry2017，60，5： | 6 |
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