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Sample records for china ii insights

  1. China's Propaganda in the United States during World War II.

    ERIC Educational Resources Information Center

    Tsang, Kuo-jen

    Drawing data from a variety of sources, a study was undertaken to place China's propaganda activities in the United States during World War II into a historical perspective. Results showed that China's propaganda efforts consisted of official and unofficial activities and activities directed toward overseas Chinese. The official activities were…

  2. U.S.-China Strategic Dialogue, Phase II

    DTIC Science & Technology

    2007-04-12

    Chinese Presentation 12:00-1:30p Lunch – Hibiscus Suite (Kalia Tower-2nd floor) 1:30p Panel II: Crisis Escalation in Theory and History Paper...Lunch Hibiscus Suite (Kalia Tower-2nd floor) 1:30p Panel IV: Nuclear Weapons Safety and Security: Comparing national approaches and discussing... Hibiscus Suite (Kalia Tower-2nd floor) 25 APPENDIX II: CONFERENCE PARTICIPANTS 26 China Rear Admiral Yang Yi Director Institute of

  3. Regional characterization of Western China-II

    SciTech Connect

    Randall, G.E.; Hartse, H.E.; Phillips, W.S.; Taylor, S.R.

    1996-10-01

    As part of the CTBT Research and Development regional characterization effort, geological, geophysical, and seismic data are being assembled and organized for inclusion in a knowledge base for China. The authors have continued their analysis using data form the station WMQ of the Chinese Digital Seismic Network (CDSN) and the IRIS station AAK. They are also acquiring and analyzing data from stations that are designated as (or near a designated) primary or secondary CTBT monitoring station. Regional seismograms are being analyzed to construct travel time curves, velocity models, attenuation characteristics, and to quantify regional propagation effects such as phase blockages. Using locations from the USGS Preliminary Determination of Epicenters (PDE) they have identified Pn, Pg, Sn, and Lg phases, constructed travel time curves, and estimated apparent velocities using linear regression. Amplitudes for the seismic phases have been measured using bandpassed waveforms and a series of magnitude relations have been determined for Western China. Studies of path specific propagation efficiency of the seismic phases have mapped blockages and also identified a possible set of observations that can be used to identify intermediate depth (> 100 im) seismic events in the Pamir-Hindu Kush seismic zone. Chinese seismicity catalogs from the USGS and Chinese State Seismological Bureau (SSB) are being used to identify and obtain seismic data (including mine seismicity) and information for lower magnitude events. Clustering analysis has been used to identify seismicity clusters in space with origin times that are distributed during daylight hours which suggest mining operations. These clusters are being investigated with imagery to attempt to identify precise mine locations.

  4. Insight into asthenospheric seismic anisotropy and deformation in Mainland China

    NASA Astrophysics Data System (ADS)

    Zhu, Tao

    2017-04-01

    Seismic anisotropy can provide direct constrains on asthenospheric deformation which also can be induced by the inherent mantle flow within our planet. Mantle flow calculations thus have been an effective tool to probe asthenospheric anisotropy. The seismic anisotropy probed by shear wave splitting (SWS) dominantly displays single-layer anisotropy, which allows us to infer the asthenospheric source of SWS and qualitatively evaluate asthenospheric deformation using mantle flow calculations in Mainland China. To date, simple asthenospheric flow (SAF) model has commonly been used to probe asthenospheric anisotropy in Mainland China. This model yields the anisotropy aligning along the direction of absolute plate motion and actually does not consider the effects of mantle flow which is inherent within our planet. To our knowledge, mantle flow is of importance to seismic anisotropy since it may lead to observation-comparable geophysical fields and seismic anisotropy. Therefore, in order to evaluate the effects of mantle flow and probe the more proper interpretation on seismic anisotropy in Mainland China, mantle flow models driven by plate motion (plate-driven) and by a combination of plate motion and mantle density heterogeneity (plate-density-driven) are used to predict the fast polarization direction (FPD) of SWS. Our results indicate that: plate-driven or plate-density driven mantle flow has dramatic effects on the development of seismic anisotropy when compared with SAF; plate-driven flow controls the FPD and large-strain-induced anisotropy strength while thermal mantle flow dominates the anisotropy strength due to low strain; asthenospheric flow is an assignable contributor to seismic anisotropy, and the asthenosphere is undergoing low, large or moderate shear deformation controlled by the strain model, the flow plane/flow direction model or the both in most regions of central and eastern China; and the asthenosphere is under more rapid extension deformation in

  5. Insight and attitudes towards medication among inpatients with chronic schizophrenia in the US and China.

    PubMed

    Mohamed, Somaia; Rosenheck, Robert; He, Hongbo; Yuping, Ning

    2014-07-01

    The impact of culture on insight on illness and attitudes towards medication among patients with schizophrenia has not been well studied. We compared inpatients in the US and in China (a culture that numerous studies have shown heavily stigmatizes mental illness and psychosis), on measures of insight and acceptance of medication, controlling for overall severity of schizophrenia symptoms. Clinical antipsychotic treatment for intervention effectiveness (CATIE) was a large study of pharmacotherapy of people with schizophrenia across the US. Insight was measured using the insight and treatment attitudes questionnaire (ITAQ) and attitudes towards medication by the drug attitude inventory (DAI) and symptoms of schizophrenia by the Positive and Negative Syndrome Scale (PANSS). These measures were applied to a sample of hospitalized patients diagnosed with schizophrenia at the Guangzhou Psychiatric hospital, the largest psychiatric hospital in Southern China. Mean ITAQ and DAI scores, net of total schizophrenia symptoms and other differences were compared at the time of admission using analysis of covariance. Both insight and favourable attitudes towards medication were significantly and substantially lower in the sample from Guangzhou on bivariate analysis even after adjusting for severity of overall schizophrenia symptoms on the PANSS. Inpatients in China had far lower scores on measures of insight and acceptance of their need for and benefits of medication, controlling for overall severity of schizophrenia symptoms, suggesting a significant impact of Chinese culture which is presumed to more heavily stigmatize mental illness and especially psychosis, although other explanations can not be ruled out.

  6. Frequency tuning with RFQ temperature in China ADS Injector II

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Huang, Jian-Long; Zhang, Xiao-Qi; Zhang, Bin; He, Yuan; Zhang, Zhou-Li; Shi, Ai-Min

    2016-03-01

    A 162.5 MHz four-vane radio frequency quadruple (RFQ) accelerator has been developed at the Institute of Modern Physics (IMP) for Injector II of the China ADS linac. The RFQ will operate in continuous wave mode at 100 kW. For the designed 10 mA beam, the additional RF power dissipation will induce a very large reflection of power. A water-temperature controlling system will be used to reduce the power reflection by tuning the frequency of the RFQ. The tuning capability of the water temperature is studied under different configurations of cooling water. Simulations and experiment are compared in this paper. The experimental results agree well with simulation using ANSYS. This can be used as a reference to tune the RFQ in beam commissioning. Supported by National Natural Science Foundation of China (91026001)

  7. New insights into bacterial type II polyketide biosynthesis

    PubMed Central

    Zhang, Zhuan; Pan, Hai-Xue; Tang, Gong-Li

    2017-01-01

    Bacterial aromatic polyketides, exemplified by anthracyclines, angucyclines, tetracyclines, and pentangular polyphenols, are a large family of natural products with diverse structures and biological activities and are usually biosynthesized by type II polyketide synthases (PKSs). Since the starting point of biosynthesis and combinatorial biosynthesis in 1984–1985, there has been a continuous effort to investigate the biosynthetic logic of aromatic polyketides owing to the urgent need of developing promising therapeutic candidates from these compounds. Recently, significant advances in the structural and mechanistic identification of enzymes involved in aromatic polyketide biosynthesis have been made on the basis of novel genetic, biochemical, and chemical technologies. This review highlights the progress in bacterial type II PKSs in the past three years (2013–2016). Moreover, novel compounds discovered or created by genome mining and biosynthetic engineering are also included. PMID:28299197

  8. New Insight into GO, Cadmium(II), Phosphate Interaction and Its Role in GO Colloidal Behavior.

    PubMed

    Ren, Xuemei; Wu, Qunyan; Xu, Huan; Shao, Dadong; Tan, Xiaoli; Shi, Weiqun; Chen, Changlun; Li, Jiaxing; Chai, Zhifang; Hayat, Tasawar; Wang, Xiangke

    2016-09-06

    This study establishes the relationship between the graphene oxide (GO) colloidal behavior and the co-adsorption of Cd(II) and phosphate (P(V)) on GO. Results reveal that the interactions among GO, Cd(II), and P(V) exhibit a significant dependence on solution chemistry and addition sequences and that these interactions subsequently affect the GO colloidal behavior. The GO aggregation is pH-dependent at pH < 4.0 and depends apparently on the binding ability of Cd(II) to GO at pH > 4.0. When the components were added simultaneously, the presence of P(V) enhances the GO binding capacity toward Cd(II), confirmed by theoretical calculation, resulting in the greater destabilizing influence of Cd(II) + P(V) on GO than Cd(II) at pH 3.0-9.5, while the formation of Cd3(PO4)2 precipitate leads to a lower destabilizing influence of Cd(II) + P(V) on GO than Cd(II) at pH > 9.5. Both pH and addition sequence affect the destabilizing ability of Cd(II) + P(V). These new insights are expected to provide valuable information not only for the application of GO as a potential adsorbent in multicomponent systems for heavy metal ion and oxyanion co-removal but also for the fate and risk assessment of GO after serving as heavy metal ion and oxyanion carrier.

  9. Taxonomic and functional diversity provides insight into microbial pathways and stress responses in the saline Qinghai Lake, China.

    PubMed

    Huang, Qiuyuan; Briggs, Brandon R; Dong, Hailiang; Jiang, Hongchen; Wu, Geng; Edwardson, Christian; De Vlaminck, Iwijn; Quake, Stephen

    2014-01-01

    Microbe-mediated biogeochemical cycles contribute to the global climate system and have sensitive responses and feedbacks to environmental stress caused by climate change. Yet, little is known about the effects of microbial biodiversity (i.e., taxonmic and functional diversity) on biogeochemical cycles in ecosytems that are highly sensitive to climate change. One such sensitive ecosystem is Qinghai Lake, a high-elevation (3196 m) saline (1.4%) lake located on the Tibetan Plateau, China. This study provides baseline information on the microbial taxonomic and functional diversity as well as the associated stress response genes. Illumina metagenomic and metatranscriptomic datasets were generated from lake water samples collected at two sites (B and E). Autotrophic Cyanobacteria dominated the DNA samples, while heterotrophic Proteobacteria dominated the RNA samples at both sites. Photoheterotrophic Loktanella was also present at both sites. Photosystem II was the most active pathway at site B; while, oxidative phosphorylation was most active at site E. Organisms that expressed photosystem II or oxidative phosphorylation also expressed genes involved in photoprotection and oxidative stress, respectively. Assimilatory pathways associated with the nitrogen cycle were dominant at both sites. Results also indicate a positive relationship between functional diversity and the number of stress response genes. This study provides insight into the stress resilience of microbial metabolic pathways supported by greater taxonomic diversity, which may affect the microbial community response to climate change.

  10. Taxonomic and Functional Diversity Provides Insight into Microbial Pathways and Stress Responses in the Saline Qinghai Lake, China

    PubMed Central

    Dong, Hailiang; Jiang, Hongchen; Wu, Geng; Edwardson, Christian; De Vlaminck, Iwijn; Quake, Stephen

    2014-01-01

    Microbe-mediated biogeochemical cycles contribute to the global climate system and have sensitive responses and feedbacks to environmental stress caused by climate change. Yet, little is known about the effects of microbial biodiversity (i.e., taxonmic and functional diversity) on biogeochemical cycles in ecosytems that are highly sensitive to climate change. One such sensitive ecosystem is Qinghai Lake, a high-elevation (3196 m) saline (1.4%) lake located on the Tibetan Plateau, China. This study provides baseline information on the microbial taxonomic and functional diversity as well as the associated stress response genes. Illumina metagenomic and metatranscriptomic datasets were generated from lake water samples collected at two sites (B and E). Autotrophic Cyanobacteria dominated the DNA samples, while heterotrophic Proteobacteria dominated the RNA samples at both sites. Photoheterotrophic Loktanella was also present at both sites. Photosystem II was the most active pathway at site B; while, oxidative phosphorylation was most active at site E. Organisms that expressed photosystem II or oxidative phosphorylation also expressed genes involved in photoprotection and oxidative stress, respectively. Assimilatory pathways associated with the nitrogen cycle were dominant at both sites. Results also indicate a positive relationship between functional diversity and the number of stress response genes. This study provides insight into the stress resilience of microbial metabolic pathways supported by greater taxonomic diversity, which may affect the microbial community response to climate change. PMID:25365331

  11. First report of peste des petits ruminants virus lineage II in Hydropotes inermis, China.

    PubMed

    Zhou, X Y; Wang, Y; Zhu, J; Miao, Q-H; Zhu, L Q; Zhan, S H; Wang, G J; Liu, G Q

    2017-07-23

    In this study, we investigated an outbreak of peste des petits ruminants (PPR) at a Hydropotes inermis (water deer) farm in Anhui Province, China. These results demonstrated that PPR viruses (PPRVs) can infect H. inermis and also revealed that virulent lineage II PPRVs exist in China, where they have been responsible for the deaths of wild animals. The government should pay close attention to the threat of PPRV epidemiology in China. © 2017 Blackwell Verlag GmbH.

  12. Structural Insights into Substrate Binding of Brown Spider Venom Class II Phospholipases D.

    PubMed

    Coronado, M A; Ullah, A; da Silva, L S; Chaves-Moreira, D; Vuitika, L; Chaim, O M; Veiga, S S; Chahine, J; Murakami, M T; Arni, R K

    2015-01-01

    Phospholipases D (PLDs), the major dermonecrotic factors from brown spider venoms, trigger a range of biological reactions both in vitro and in vivo. Despite their clinical relevance in loxoscelism, structural data is restricted to the apo-form of these enzymes, which has been instrumental in understanding the functional differences between the class I and II spider PLDs. The crystal structures of the native class II PLD from Loxosceles intermedia complexed with myo-inositol 1-phosphate and the inactive mutant H12A complexed with fatty acids indicate the existence of a strong ligand-dependent conformation change of the highly conserved aromatic residues, Tyr 223 and Trp225 indicating their roles in substrate binding. These results provided insights into the structural determinants for substrate recognition and binding by class II PLDs.

  13. Spatiotemporal dynamics of condensins I and II: evolutionary insights from the primitive red alga Cyanidioschyzon merolae

    PubMed Central

    Fujiwara, Takayuki; Tanaka, Kan; Kuroiwa, Tsuneyoshi; Hirano, Tatsuya

    2013-01-01

    Condensins are multisubunit complexes that play central roles in chromosome organization and segregation in eukaryotes. Many eukaryotic species have two different condensin complexes (condensins I and II), although some species, such as fungi, have condensin I only. Here we use the red alga Cyanidioschyzon merolae as a model organism because it represents the smallest and simplest organism that is predicted to possess both condensins I and II. We demonstrate that, despite the great evolutionary distance, spatiotemporal dynamics of condensins in C. merolae is strikingly similar to that observed in mammalian cells: condensin II is nuclear throughout the cell cycle, whereas condensin I appears on chromosomes only after the nuclear envelope partially dissolves at prometaphase. Unlike in mammalian cells, however, condensin II is confined to centromeres in metaphase, whereas condensin I distributes more broadly along arms. We firmly establish a targeted gene disruption technique in this organism and find, to our surprise, that condensin II is not essential for mitosis under laboratory growth conditions, although it plays a crucial role in facilitating sister centromere resolution in the presence of a microtubule drug. The results provide fundamental insights into the evolution of condensin-based chromosome architecture and dynamics. PMID:23783031

  14. Mechanistic insights into electrocatalytic CO2 reduction within [Ru(II)(tpy)(NN)X]n+ architectures.

    PubMed

    White, Travis A; Maji, Somnath; Ott, Sascha

    2014-10-28

    A series of Ru(II)-polypyridyl complexes of the design [Ru(II)(tpy)(NN)X](n+) (tpy = 2,2':6',2''-terpyridine; NN = bidentate polypyridine; X = Cl(-) or CH3CN; n = 1 or 2) have been synthesized and analyzed for their ability to function as electrocatalysts in the reduction of CO2 to CO. Varying the electron-donating/withdrawing character of the NN polypyridyl ligand has allowed for modification of electron density at the formally Ru(II) metal center. Complexes where X = Cl(-) display ligand substitution for CH3CN with differing rates of Cl(-) dissociation (k-Cl), therefore providing a degree of insight into the electron density and thus the chemical activity at the Ru(II) center. Detailed analysis of the cyclic voltammograms under argon vs. CO2 atmospheres using multiple switching potentials and scan rates ranging from ν = 25-2000 mV s(-1) has painted a picture of how monodentate ligand lability due to NN polypyridyl electron-donating character is related to electrocatalytic CO2 reduction activity of Ru(II)-polypyridyl complexes. From these studies, multiple mechanistic pathways towards generating the catalytically active [Ru(tpy(-))(NN(-))CO2](0) species are proposed and differ via the order of electrochemical and chemical processes.

  15. DSM-IV Axis II personality disorders and suicide and attempted suicide in China.

    PubMed

    Tong, Yongsheng; Phillips, Michael R; Conner, Kenneth R

    2016-10-01

    There are meagre data on Axis II personality disorders and suicidal behaviour in China. To describe the prevalence of Axis II personality disorders in suicides and suicide attempts in China and to estimate risk for these outcomes associated with personality disorders. People who died by suicide (n = 151), people who attempted suicide (n = 118) and living community controls (n = 140) were randomly sampled from four Chinese counties and studied using the Structured Clinical Interviews for DSM-IV-TR Axis I Disorders (SCID-I) and Axis II Personality Disorders (SCID-II). We also determined the prevalence of subthreshold versions of ten DSM-IV personality disorders. Axis II personality disorders were present in 7% of the suicide group, 6% of the suicide attempt group and 1% of the control group. Threshold and subthreshold personality disorders had adjusted odds ratios (point estimates) in the range of 2.7-8.0 for suicide and for suicide attempts. Axis II personality disorders may confer increased risk for suicidal behaviour in China, but their low prevalence in the community and among people with suicidal behaviour suggests that other personality constructs such as select dimensional traits may be a more fruitful avenue for understanding and preventing suicide in China. © The Royal College of Psychiatrists 2016.

  16. Removal of lead(II) and copper(II) from aqueous solution using foitite from Linshou mine in Hebei, China.

    PubMed

    He, Dengliang; Yin, Guangfu; Dong, Faqin; Liu, Laibao; Tan, Xiaoli; He, Wangyang

    2011-01-01

    Foitite from Linshou mine in China's Hebei province was investigated as an adsorbent to remove Pb(II) and Cu(II) from aqueous solution. The results showed that foitite can readily remove heavy metal ions from aqueous solution. The data shows that the metal uptake for Pb(II) increases rapidly, accounting for 74.47% when contact time was 2 min. In contrast to Pb(ll), there was a worse capability for adsorption of Cu(II). In the first 4 min, the metal uptake accounted for 34.7%. According to the analytical results obtained from X-ray diffraction, laser Raman spectrum, X-ray energy dispersive spectrometer, and Zeta potential, the removal mechanism of Pb(II) and Cu(II) by using foitite can be explained as following: firstly, the existence of an electrostatic field around foitite particles can attract heavy metal ions and consequently combine heavy metal ions with OH; secondly, heavy metal ions in the solution are exchanged with the Fe3+ and Al3+ in the foitite.

  17. Adsorption behavior and mechanism of Cd(II) on loess soil from China.

    PubMed

    Wang, Yan; Tang, Xiaowu; Chen, Yunmin; Zhan, Liangtong; Li, Zhenze; Tang, Qiang

    2009-12-15

    Cadmium is a toxic heavy metal that has caused serious public health problems. It is necessary to find a cost effective method to deal with wastewater containing Cd(II). Loess soils in China have proven to be a potential adsorbent for Cd(II) removal from wastewater. The adsorption capacity of loess towards Cd(II) has been determined to be about 9.37 mg g(-1). Slurry concentration, initial solution pH, reaction time and temperature have also been found to significantly influence the efficiency of Cd(II) removal. The adsorption isotherms and kinetics of loess soil from China can be best-fit with the Langmuir model and pseudo-second order kinetics model, respectively. The thermodynamic analysis revealed that the adsorption process was spontaneous, endothermic and the system disorder increased with duration. The natural organic matter in loess soil is mainly responsible for Cd(II) removal at pH < 4.2, while clay minerals contribute to a further gradual adsorption process. Chemical precipitation dominates the adsorption stage at pH > 8.97. Further studies using X-ray diffraction, Fourier transform infrared spectra of Cd(II) laden loess soil and Cd(II) species distribution have confirmed the adsorption mechanism.

  18. Seismic imaging of North China: insight into intraplate volcanism and seismotectonics

    NASA Astrophysics Data System (ADS)

    Zhao, D.

    2004-12-01

    and middle crust and thus contribute to the initiation of the large crustal earthquakes. Similar features are also found in the source areas of the 1995 Kobe earthquake (M 7.2) in Japan (Zhao et al., 1996) and the 2001 Bhuj earthquake (M 7.8) in India (Mishra and Zhao, 2003). Zhao, D. (2004) Global tomographic images of mantle plumes and subducting slabs: insight into deep Earth dynamics. Phys. Earth Planet. Inter. 146, 3-34. Zhao, D., J. Lei, R. Tang (2004) Origin of the intraplate Changbai volcano in Northeast China: Evidence from seismic tomography. Chinese Science Bulletin 49(13), 1401-1408. Huang, J., D. Zhao (2004) Crustal heterogeneity and seismotectonics of the region around Beijing, China. Tectonophysics 385, 159-180.

  19. Structural and spectroscopic characterization of iron(II), cobalt(II), and nickel(II) ortho-dihalophenolate complexes: insights into metal-halogen secondary bonding.

    PubMed

    Machonkin, Timothy E; Boshart, Monica D; Schofield, Jeremy A; Rodriguez, Meghan M; Grubel, Katarzyna; Rokhsana, Dalia; Brennessel, William W; Holland, Patrick L

    2014-09-15

    Metal complexes incorporating the tris(3,5-diphenylpyrazolyl)borate ligand (Tp(Ph2)) and ortho-dihalophenolates were synthesized and characterized in order to explore metal-halogen secondary bonding in biorelevant model complexes. The complexes Tp(Ph2)ML were synthesized and structurally characterized, where M was Fe(II), Co(II), or Ni(II) and L was either 2,6-dichloro- or 2,6-dibromophenolate. All six complexes exhibited metal-halogen secondary bonds in the solid state, with distances ranging from 2.56 Å for the Tp(Ph2)Ni(2,6-dichlorophenolate) complex to 2.88 Å for the Tp(Ph2)Fe(2,6-dibromophenolate) complex. Variable temperature NMR spectra of the Tp(Ph2)Co(2,6-dichlorophenolate) and Tp(Ph2)Ni(2,6-dichlorophenolate) complexes showed that rotation of the phenolate, which requires loss of the secondary bond, has an activation barrier of ~30 and ~37 kJ/mol, respectively. Density functional theory calculations support the presence of a barrier for disruption of the metal-halogen interaction during rotation of the phenolate. On the other hand, calculations using the spectroscopically calibrated angular overlap method suggest essentially no contribution of the halogen to the ligand-field splitting. Overall, these results provide the first quantitative measure of the strength of a metal-halogen secondary bond and demonstrate that it is a weak noncovalent interaction comparable in strength to a hydrogen bond. These results provide insight into the origin of the specificity of the enzyme 2,6-dichlorohydroquinone 1,2-dioxygenase (PcpA), which is specific for ortho-dihalohydroquinone substrates and phenol inhibitors.

  20. The China Mental Health Survey: II. Design and field procedures.

    PubMed

    Liu, Zhaorui; Huang, Yueqin; Lv, Ping; Zhang, Tingting; Wang, Hong; Li, Qiang; Yan, Jie; Yu, Yaqin; Kou, Changgui; Xu, Xiufeng; Lu, Jin; Wang, Zhizhong; Qiu, Hongyan; Xu, Yifeng; He, Yanling; Li, Tao; Guo, Wanjun; Tian, Hongjun; Xu, Guangming; Xu, Xiangdong; Ma, Yanjuan; Wang, Linhong; Wang, Limin; Yan, Yongping; Wang, Bo; Xiao, Shuiyuan; Zhou, Liang; Li, Lingjiang; Tan, Liwen; Chen, Hongguang; Ma, Chao

    2016-11-01

    China Mental Health Survey (CMHS), which was carried out from July 2013 to March 2015, was the first national representative community survey of mental disorders and mental health services in China using computer-assisted personal interview (CAPI). Face-to-face interviews were finished in the homes of respondents who were selected from a nationally representative multi-stage disproportionate stratified sampling procedure. Sample selection was integrated with the National Chronic Disease and Risk Factor Surveillance Survey administered by the National Centre for Chronic and Non-communicable Disease Control and Prevention in 2013, which made it possible to obtain both physical and mental health information of Chinese community population. One-stage design of data collection was used in the CMHS to obtain the information of mental disorders, including mood disorders, anxiety disorders, and substance use disorders, while two-stage design was applied for schizophrenia and other psychotic disorders, and dementia. A total of 28,140 respondents finished the survey with 72.9% of the overall response rate. This paper describes the survey mode, fieldwork organization, procedures, and the sample design and weighting of the CMHS. Detailed information is presented on the establishment of a new payment scheme for interviewers, results of the quality control in both stages, and evaluations to the weighting.

  1. Nursing Practice Guidelines in China do Need Reform: A Critical Appraisal Using the AGREE II Instrument.

    PubMed

    Jin, Yinghui; Wang, Yunyun; Zhang, Yao; Ma, Yue; Li, Yan; Lu, Cui; Wang, Wei; Li, Ge; Shang, Hongcai

    2016-04-01

    An increasing number of nursing practice guidelines (NPGs) of varying methodological and reporting quality have been issued and published in international journals. Currently, the quality of NPGs in mainland China has not been explored. To assess the quality of NPGs in China mainland using the AGREE II (Advancing Guideline Development, Reporting and Evaluation in Health Care) instrument. The authors searched the electronic databases of Chinese Biomedical Literature Database, China National Knowledge Infrastructure, The VIP Database, Wan Fang Database, Chinese Master's Theses Full-Text Database, China Doctor Dissertation Full-Text Database, and China Proceedings of Conference Full-Text Database and the web of China Guideline Clearinghouse for NPGs in China published from the inception of databases to December, 2013. Four independent assessors rated the quality of each guideline using AGREE II. The authors classified NPGs into two types: evidence-based NPG (EB-NPG) and consensus-based NPG (CB-NPG), and compared their quality. The authors also considered whether the quality of NPGs changed over time. Forty-two NPGs were appraised. Methodological rigor and reporting of NPGs were poor. Across all guidelines, the appraisers assigned the highest scores to the domain "scope and purpose," and the lowest scored to the domain of "editorial independence." EB-NPGs were significantly superior to the CB-NPGs in the domains of "stakeholder involvement," "rigor of development," and "editorial independence." There was no improvement over time for all domains. This research found an absence of a systematic guideline development methodology and a tendency to rely on expert opinion in the process of developing NPGs. The readers should consider these flaws and limitations when using recommendations in those NPGs. © 2016 Sigma Theta Tau International.

  2. Genomic insights into Mn(II) oxidation by the marine alphaproteobacterium Aurantimonas sp. strain SI85-9A1.

    PubMed

    Dick, Gregory J; Podell, Sheila; Johnson, Hope A; Rivera-Espinoza, Yadira; Bernier-Latmani, Rizlan; McCarthy, James K; Torpey, Justin W; Clement, Brian G; Gaasterland, Terry; Tebo, Bradley M

    2008-05-01

    Microbial Mn(II) oxidation has important biogeochemical consequences in marine, freshwater, and terrestrial environments, but many aspects of the physiology and biochemistry of this process remain obscure. Here, we report genomic insights into Mn(II) oxidation by the marine alphaproteobacterium Aurantimonas sp. strain SI85-9A1, isolated from the oxic/anoxic interface of a stratified fjord. The SI85-9A1 genome harbors the genetic potential for metabolic versatility, with genes for organoheterotrophy, methylotrophy, oxidation of sulfur and carbon monoxide, the ability to grow over a wide range of O(2) concentrations (including microaerobic conditions), and the complete Calvin cycle for carbon fixation. Although no growth could be detected under autotrophic conditions with Mn(II) as the sole electron donor, cultures of SI85-9A1 grown on glycerol are dramatically stimulated by addition of Mn(II), suggesting an energetic benefit from Mn(II) oxidation. A putative Mn(II) oxidase is encoded by duplicated multicopper oxidase genes that have a complex evolutionary history including multiple gene duplication, loss, and ancient horizontal transfer events. The Mn(II) oxidase was most abundant in the extracellular fraction, where it cooccurs with a putative hemolysin-type Ca(2+)-binding peroxidase. Regulatory elements governing the cellular response to Fe and Mn concentration were identified, and 39 targets of these regulators were detected. The putative Mn(II) oxidase genes were not among the predicted targets, indicating that regulation of Mn(II) oxidation is controlled by other factors yet to be identified. Overall, our results provide novel insights into the physiology and biochemistry of Mn(II) oxidation and reveal a genome specialized for life at the oxic/anoxic interface.

  3. Insight into selectivity of peptidomimetic inhibitors with modified statine core for plasmepsin II of Plasmodium falciparum over human cathepsin D.

    PubMed

    Dali, Brice; Keita, Melalie; Megnassan, Eugene; Frecer, Vladimir; Miertus, Stanislav

    2012-04-01

    Plasmepsin II (PlmII), an aspartic protease expressed in the food vacuole of Plasmodium falciparum (pf), cleaves the hemoglobin of the host during the erythrocytic stage of the parasite life cycle. Various peptidomimetic inhibitors of PlmII reported so far discriminate poorly between the drug target and aspartic proteases of the host organism, e.g., human cathepsinD (hCatD). hCatD is a protein digestion enzyme and signaling molecule involved in a variety of physiological processes; therefore, inhibition of hCatD by PlmII inhibitors may lead to pathophysiological conditions. In this study, binding of PlmII inhibitors has been modeled using the crystal structures of pfPlmII and hCatD complexes to gain insight into structural requirements underlying the target selectivity. A series of 26 inhibitors were modeled in the binding clefts of the pfPlmII and hCatD to establish QSAR models of the protease inhibition. In addition, 3D-QSAR pharmacophore models were generated for each enzyme. It was concluded that the contributions of the P(2) and P(3') residues to the inhibitor's binding affinity are responsible for the target selectivity. Based on these findings, new inhibitor candidates were designed with predicted inhibition constants K (pre)(i PlmII) reaching 0.2nm and selectivity index (S.I.)=K(pre)(i PlmII) >1200.

  4. New insights on the ocean circulation and its coupling with biogeochemistry in the South China Sea

    NASA Astrophysics Data System (ADS)

    Gan, J.; Dai, M.

    2016-12-01

    The South China Sea (SCS) is a regional ocean basin. It features unique circulation patterns governed by a suit of inter-linked physical processes spanning from the western ocean boundary current, monsoonal wind/tidal forcing, and flow-topography interaction in both the SCS and the adjacent oceans. Based on a decade-long interdisciplinary study, this presentation highlights our new insights on the three-dimensional ocean circulation and dynamics as well as their coupling with biogeochemistry in the SCS. The SCS circulation responds extrinsically to the flow exchange with adjacent oceans through the straits around the periphery of the SCS, and intrinsically to basin physical processes. We reveal that the SCS has a cyclonic-anticyclonic-cyclonic (CAC) circulation pattern in the upper-middle-lower layers, which is related to a lateral planetary vorticity flux of the inflow-outflow-inflow transport in the respective layer in the Luzon Strait. The Joint Effects of Baroclinicity and Relief (JEBAR), as a result of CAC circulation-topography interaction, acts as an intrinsic response to the CAC circulation. The revealing of the CAC circulation and its controlling physics fills our knowledge gap of time-dependent, three-dimensional circulation in the SCS. Such a circulation largely shapes the transport fluxes of chemicals between the SCS and adjacent oceans, on top of which is the intrinsic chemical and biological processes within the SCS. We examine the dynamic pathway in the SCS that facilitates the vertical transport of nutrients and carbon from the depth into the euphotic zone where active biological metabolism takes place. The biogeochemical variability within the SCS is largely linked with controls of the three-dimensional biogeochemical fluxes associated extrinsically with the lateral transport and intrinsically with localized vertical motion in the basin. Based on validated hindcasting results at the present time, we project and reason the long-term trends of

  5. Structural basis for the inhibition of truncated islet amyloid polypeptide aggregation by Cu(II): insights into the bioinorganic chemistry of type II diabetes.

    PubMed

    Rivillas-Acevedo, Lina; Sánchez-López, Carolina; Amero, Carlos; Quintanar, Liliana

    2015-04-20

    Type 2 diabetes (T2D) is one of the most common chronic diseases, affecting over 300 million people worldwide. One of the hallmarks of T2D is the presence of amyloid deposits of human islet amyloid polypeptide (IAPP) in the islets of Langerhans of pancreatic β-cells. Recent reports indicate that Cu(II) can inhibit the aggregation of human IAPP, although the mechanism for this inhibitory effect is not clear. In this study, different spectroscopic techniques and model fragments of IAPP were employed to shed light on the structural basis for the interaction of Cu(II) with human IAPP. Our results show that Cu(II) anchors to His18 and the subsequent amide groups toward the C-terminal, forming a complex with an equatorial coordination mode 3N1O at physiological pH. Cu(II) binding to truncated IAPP at the His18 region is the key event for its inhibitory effect in amyloid aggregation. Electron paramagnetic resonance studies indicate that the monomeric Cu(II)-IAPP(15-22) complex differs significantly from Cu(II) bound to mature IAPP(15-22) fibers, suggesting that copper binding to monomeric IAPP(15-22) competes with the conformation changes needed to form β-sheet structures, thus delaying fibril formation. A general mechanism is proposed for the inhibitory effect of copper and other imidazole-binding metal ions in IAPP amyloid formation, providing further insights into the bioinorganic chemistry of T2D.

  6. Insight to the Epidemiology and Risk Factors of Extrapulmonary Tuberculosis in Tianjin, China during 2006-2011

    PubMed Central

    Wang, Xiaoqing; Yang, Zhenhua; Fu, Yanyong; Zhang, Guoqin; Wang, Xu; Zhang, Yuhua; Wang, Xiexiu

    2014-01-01

    Background The proportion of extrapulmonary tuberculosis (EPTB) among all the reported tuberculosis (TB) cases has increased in different populations. Despite the large burden of TB in China, the epidemiology of EPTB in China remains largely understudied and the risk factors for having EPTB diagnosis in China have not been identified. Methods To gain insight to EPTB epidemiology in China, we analyzed TB surveillance data collected in Tianjin, China, during 2006 to 2011. The frequency of EPTB among all TB cases and within different socio-demographic groups of the study patients aged 15 years and older was determined for EPTB in general and by specific types. The distribution of socio-demographic characteristics was compared between pulmonary TB (PTB) group and EPTB group by chi-square test. Crude and multiple logistic regression-derived adjusted odds ratios (aOR) and 95% confidence intervals (CI) were determined to assess the associations between having EPTB diagnosis and each individual explanatory variable in question. Results About one-tenth (1,512/14,561) of the patients investigated in this study had EPTB. Of these 1,512 EPTB cases, about two thirds were pleural TB. Significant difference in age, occupation, and urbanity of residence were found between PTB and EPTB groups (p<0.05). Patients with EPTB diagnosis were more likely to be 65 years or older (aOR = 1.22, 95% CI: 1.02, 1.46), to be retired (aOR = 1.37, 95% CI: 1.08, 1.75), and to live in urban areas (aOR = 1 38, 95% CI: 1.22, 1.55). Conclusions The findings of this study extends the knowledgebase of EPTB epidemiology in developing countries and highlight the need for improved EPTB detection in China, especially in subpopulations with high risk for EPTB or having limited access to medical facilities with adequate capacity for EPTB diagnosis. PMID:25494360

  7. Molecular, ethno-spatial epidemiology of leprosy in China: Novel insights for tracing leprosy in endemic and non endemic provinces

    PubMed Central

    Weng, Xiaoman; Xing, Yan; Liu, Jian; Wang, Yonghong; Ning, Yong; Li, Ming; Wu, Wenbin; Zhang, Lianhua; Li, Wei; Heiden, Jason Vander; Vissa, Varalakshmi

    2013-01-01

    Leprosy continues to be detected at near stable rates in China even with established control programs, necessitating new knowledge and alternative methods to interrupt transmission. A molecular epidemiology investigation of 190 patients was undertaken to define M. leprae strain types and discern genetic relationships and clusters in endemic and non-endemic regions spanning seventeen provinces and two autonomous regions. The findings support multiple locus variable number of tandem repeat (VNTR) analysis as a useful tool in uncovering characteristic patterns across the multiethnic and divergent geographic landscape of China. Several scenarios of clustering of leprosy from township to provincial to regional levels were recognized, while recent occupational or remote migration showed geographical separation of certain strains. First, prior studies indicated that of the four major M. leprae subtypes defined by single nucleotide polymorphisms (SNPs), only type 3 was present in China, purportedly entering from Europe/West/Central Asia via the Silk Road. However, this study revealed VNTR linked strains that are of type 1 in Guangdong, Fujian and Guangxi in southern China. Second, a subset of VNTR distinguishable strains of type 3, co-exist in these provinces. Third, type 3 strains with rpoT VNTR allele of 4, detected in Japan and Korea were discovered in Jiangsu and Anhui in the east and in western Sichuan bordering Tibet. Fourth, considering the overall genetic diversity, strains of endemic counties of Qiubei, Yunnan; Xing Yi, Guizhou; and across Sichuan in southwest were related. However, closer inspection showed distinct local strains and clusters. Altogether, these insights, primarily derived from VNTR typing, reveal multiple and overlooked paths for spread of leprosy into, within and out of China and invoke attention to historic maritime routes in the South and East China Sea. More importantly, new concepts and approaches for prospective case finding and tracking of

  8. China and India: Different Educational Paths toward Prosperity. Policy Insight, Volume 2, Issue 1

    ERIC Educational Resources Information Center

    Liu, Ying; Kumar, Krishna B.

    2008-01-01

    Different educational approaches in China and India have been successful in stimulating economic growth. The two countries started building their national education systems under comparable conditions in the late 1940s; however, different policies, strategies, and historical circumstances have led them through different routes. China has…

  9. China and India: Different Educational Paths toward Prosperity. Policy Insight, Volume 2, Issue 1

    ERIC Educational Resources Information Center

    Liu, Ying; Kumar, Krishna B.

    2008-01-01

    Different educational approaches in China and India have been successful in stimulating economic growth. The two countries started building their national education systems under comparable conditions in the late 1940s; however, different policies, strategies, and historical circumstances have led them through different routes. China has…

  10. Mineralogy and geochemistry of boehmite-rich coals: New insights from the Haerwusu Surface Mine, Jungar Coalfield, Inner Mongolia, China

    USGS Publications Warehouse

    Dai, S.; Li, D.; Chou, C.-L.; Zhao, L.; Zhang, Y.; Ren, D.; Ma, Y.; Sun, Y.

    2008-01-01

    Boehmite-rich coal of Pennsylvanian age was discovered earlier at the Heidaigou Surface Mine, Jungar Coalfield, Inner Mongolia, China. This paper reports new results on 29 bench samples of the no. 6 coal from a drill core from the adjacent Haerwusu Surface Mine, and provides new insights into the origin of the minerals and elements present. The results show that the proportion of inertinite in the no. 6 coal is higher than in other Late Paleozoic coals in northern China. Based on mineral proportions (boehmite to kaolinite ratio) and major element concentrations in the coal benches of the drill core, the no. 6 coal may be divided into five sections (I to V). Major minerals in Sections I and V are kaolinite. Sections II and IV are mainly kaolinite with a trace of boehmite, and Section III is high in boehmite. The boehmite is derived from bauxite in the weathered surface (Benxi Formation) in the sediment-source region. The no. 6 coal is rich in Al2O3 (8.89%), TiO2 (0.47%), Li (116????g/g), F (286????g/g), Ga (18????g/g), Se (6.1????g/g), Sr (350????g/g), Zr (268????g/g), REEs (172????g/g), Pb (30????g/g), and Th (17????g/g). The elements are classified into five associations by cluster analysis, i.e. Groups A, B, C, D, and E. Group A (ash-SiO2-Al2O3-Na2O-Li) and Group B (REE-Sc-In-Y-K2O-Rb-Zr-Hf-Cs-U-P2O5-Sr-Ba-Ge) are strongly correlated with ash yield and mainly have an inorganic affinity. The elements that are negatively or less strongly correlated with ash yield (with exceptions of Fe2O3, Be, V, and Ni) are grouped in the remaining three associations: Group C, Se-Pb-Hg-Th-TiO2-Bi-Nb-Ta-Cd-Sn; Group D, Co-Mo-Tl-Be-Ni-Sb-MgO-Re-Ga-W-Zn-V-Cr-F-Cu; and Group E, S-As-CaO-MnO-Fe2O3. Aluminum is mainly distributed in boehmite, followed by kaolinite. The high correlation coefficients of the Li-ash, Li-Al2O3, and Li-SiO2 pairs indicate that Li is related to the aluminosilicates in the coal. The boehmite-rich coal is high in gallium and F, which occur in boehmite and the

  11. Emission sources and atmospheric processing of carbonaceous aerosols in India and China: Insights from dual carbon isotope techniques

    NASA Astrophysics Data System (ADS)

    Andersson, A.; Kirillova, E. N.; Bosch, C.; Suresh, T.; Lee, M.; Du, K.; Sheesley, R. J.; Budhavant, K.; Gustafsson, O. M.

    2013-12-01

    The large emissions of carbonaceous aerosols, e.g., black carbon (BC), in India and China have detrimental effects on both human health and the regional climate. However, mitigation efforts as well as accurate modeling of these effects are currently hampered by large uncertainties regarding the contributions from different emission sources, including both primary and secondary processes. Here, we present dual carbon isotope constraints on emissions sources and atmospheric processing from multiple sites capturing the outflow from India and China. Radiocarbon (14C) studies of elemental carbon (EC) - a tracer for BC - show larger relative fossil contributions than expected from bottom-up emission inventories, for both India (49+-5) and China (80 +-6%). Similarly to EC, radiocarbon constraints of water soluble organic carbon (WSOC) shows substantially larger relative fossil contributions in Chinese outflow (30-50%) as compared with India, but also compared to Europe and USA (10-20%). In contrast to the radiocarbon data, stable carbon (d13C) analysis of WSOC shows substantial variability for different sites capturing the Indian outflow. Strong enrichment of heavy isotopes in WSOC is coupled to expected transport time from sources, indicating the influence of photochemical aging during transport. Such trends in the d13C signature are not observed for the EC fraction. Taken together this work show that carbon isotope techniques provide firm constraints on emission sources of different fractions of carbonaceous aerosols, and may also offer insights into atmospheric processing of these constituents during air mass transport.

  12. Direct Activation of ENaC by Angiotensin II: Recent Advances and New Insights

    PubMed Central

    Zaika, Oleg; Mamenko, Mykola; Staruschenko, Alexander

    2012-01-01

    Angiotensin II (Ang II) is the principal effector of the renin-angiotensin-aldosterone system (RAAS). It initiates myriad processes in multiple organs integrated to increase circulating volume and elevate systemic blood pressure. In the kidney, Ang II stimulates renal tubular water and salt reabsorption causing antinatriuresis and antidiuresis. Activation of RAAS is known to enhance activity of the epithelial Na+ channel (ENaC) in the aldosterone-sensitive distal nephron. In addition to its well described stimulatory actions on aldosterone secretion, Ang II is also capable to directly increase ENaC activity. In this brief review, we discuss recent findings about non-classical Ang II actions on ENaC and speculate about its relevance for renal sodium handling. PMID:23180052

  13. Insight into the Structure of Light Harvesting Complex II and its Stabilization in Detergent Solution

    SciTech Connect

    Cardoso, Mateus B; Smolensky, Dmitriy; Heller, William T; O'Neill, Hugh Michael

    2009-01-01

    The structure of spinach light-harvesting complex II (LHC II), stabilized in a solution of the detergent n-octyl-{beta}-d-glucoside (BOG), was investigated by small-angle neutron scattering (SANS). Physicochemical characterization of the isolated complex indicated that it was pure (>95%) and also in its native trimeric state. SANS with contrast variation was used to investigate the properties of the protein-detergent complex at three different H{sub 2}O/D{sub 2}O contrast match points, enabling the scattering properties of the protein and detergent to be investigated independently. The topological shape of LHC II, determined using ab initio shape restoration methods from the SANS data at the contrast match point of BOG, was consistent with the X-ray crystallographic structure of LHC II (Liu et al. Nature 2004 428, 287-292). The interactions of the protein and detergent were investigated at the contrast match point for the protein and also in 100% D{sub 2}O. The data suggested that BOG micelle structure was altered by its interaction with LHC II, but large aggregate structures were not formed. Indirect Fourier transform analysis of the LHC II/BOG scattering curves showed that the increase in the maximum dimension of the protein-detergent complex was consistent with the presence of a monolayer of detergent surrounding the protein. A model of the LHC II/BOG complex was generated to interpret the measurements made in 100% D{sub 2}O. This model adequately reproduced the overall size of the LHC II/BOG complex, but demonstrated that the detergent does not have a highly regular shape that surrounds the hydrophobic periphery of LHC II. In addition to demonstrating that natively structured LHC II can be produced for functional characterization and for use in artificial solar energy applications, the analysis and modeling approaches described here can be used for characterizing detergent-associated {alpha}-helical transmembrane proteins.

  14. Single molecule microscopy reveals mechanistic insight into RNA polymerase II preinitiation complex assembly and transcriptional activity.

    PubMed

    Horn, Abigail E; Kugel, Jennifer F; Goodrich, James A

    2016-09-06

    Transcription by RNA polymerase II (Pol II) is a complex process that requires general transcription factors and Pol II to assemble on DNA into preinitiation complexes that can begin RNA synthesis upon binding of NTPs (nucleoside triphosphate). The pathways by which preinitiation complexes form, and how this impacts transcriptional activity are not completely clear. To address these issues, we developed a single molecule system using TIRF (total internal reflection fluorescence) microscopy and purified human transcription factors, which allows us to visualize transcriptional activity at individual template molecules. We see that stable interactions between polymerase II (Pol II) and a heteroduplex DNA template do not depend on general transcription factors; however, transcriptional activity is highly dependent upon TATA-binding protein, TFIIB and TFIIF. We also found that subsets of general transcription factors and Pol II can form stable complexes that are precursors for functional transcription complexes upon addition of the remaining factors and DNA. Ultimately we found that Pol II, TATA-binding protein, TFIIB and TFIIF can form a quaternary complex in the absence of promoter DNA, indicating that a stable network of interactions exists between these proteins independent of promoter DNA. Single molecule studies can be used to learn how different modes of preinitiation complex assembly impact transcriptional activity. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. Insights into the strategies used by related group II introns to adapt successfully for the colonisation of a bacterial genome.

    PubMed

    Martínez-Rodríguez, Laura; García-Rodríguez, Fernando M; Molina-Sánchez, María Dolores; Toro, Nicolás; Martínez-Abarca, Francisco

    2014-01-01

    Group II introns are self-splicing RNAs and site-specific mobile retroelements found in bacterial and organellar genomes. The group II intron RmInt1 is present at high copy number in Sinorhizobium meliloti species, and has a multifunctional intron-encoded protein (IEP) with reverse transcriptase/maturase activities, but lacking the DNA-binding and endonuclease domains. We characterized two RmInt1-related group II introns RmInt2 from S. meliloti strain GR4 and Sr.md.I1 from S. medicae strain WSM419 in terms of splicing and mobility activities. We used both wild-type and engineered intron-donor constructs based on ribozyme ΔORF-coding sequence derivatives, and we determined the DNA target requirements for RmInt2, the element most distantly related to RmInt1. The excision and mobility patterns of intron-donor constructs expressing different combinations of IEP and intron RNA provided experimental evidence for the co-operation of IEPs and intron RNAs from related elements in intron splicing and, in some cases, in intron homing. We were also able to identify the DNA target regions recognized by these IEPs lacking the DNA endonuclease domain. Our results provide new insight into the versatility of related group II introns and the possible co-operation between these elements to facilitate the colonization of bacterial genomes.

  16. Insights into the strategies used by related group II introns to adapt successfully for the colonisation of a bacterial genome

    PubMed Central

    Martínez-Rodríguez, Laura; García-Rodríguez, Fernando M; Molina-Sánchez, María Dolores; Toro, Nicolás; Martínez-Abarca, Francisco

    2014-01-01

    Group II introns are self-splicing RNAs and site-specific mobile retroelements found in bacterial and organellar genomes. The group II intron RmInt1 is present at high copy number in Sinorhizobium meliloti species, and has a multifunctional intron-encoded protein (IEP) with reverse transcriptase/maturase activities, but lacking the DNA-binding and endonuclease domains. We characterized two RmInt1-related group II introns RmInt2 from S. meliloti strain GR4 and Sr.md.I1 from S. medicae strain WSM419 in terms of splicing and mobility activities. We used both wild-type and engineered intron-donor constructs based on ribozyme ΔORF-coding sequence derivatives, and we determined the DNA target requirements for RmInt2, the element most distantly related to RmInt1. The excision and mobility patterns of intron-donor constructs expressing different combinations of IEP and intron RNA provided experimental evidence for the co-operation of IEPs and intron RNAs from related elements in intron splicing and, in some cases, in intron homing. We were also able to identify the DNA target regions recognized by these IEPs lacking the DNA endonuclease domain. Our results provide new insight into the versatility of related group II introns and the possible co-operation between these elements to facilitate the colonization of bacterial genomes. PMID:25482895

  17. Insights into the electronic structure of Cu(II) bound to an imidazole analogue of westiellamide.

    PubMed

    Comba, Peter; Dovalil, Nina; Hanson, Graeme R; Harmer, Jeffrey R; Noble, Christopher J; Riley, Mark J; Seibold, Bjoern

    2014-12-01

    Three synthetic analogues of westiallamide, H3L(wa), have previously been synthesized (H3L(1-3)) that have a common backbone (derived from l-valine) with H3L(wa) but differ in their heterocyclic rings (imidazole, oxazole, thiazole, and oxazoline). Herein we explore in detail through high-resolution pulsed electron paramagnetic resonance (EPR) and magnetic circular dichroism (MCD) spectroscopy in conjunction with density functional theory (DFT) the geometric and electronic structures of the mono- and dinuclear Cu(II) complexes of these cyclic pseudo hexapeptides. Orientation-selective hyperfine sublevel correlation, electron nuclear double resonance, and three-pulse electron spin echo envelope modulation spectroscopy of [Cu(II)(H2L(1))(MeOH)2](+) reveal delocalization of the unpaired electron spin onto the ligating and distal nitrogens of the coordinated heterocyclic rings and that they are magnetically inequivalent. DFT calculations confirm this and show similar spin densities on the distal heteroatoms in the heterocyclic rings coordinated to the Cu(II) ion in the other cyclic pseudo hexapeptide [Cu(II)(H2L(2,3,wa))(MeOH)2](+) complexes. The magnetic inequivalencies in [Cu(II)(H2L(1))(MeOH)2](+) arise from different orientations of the heterocyclic rings coordinated to the Cu(II) ion, and the delocalization of the unpaired electron onto the distal heteroatoms within these N-methylimidazole rings depends upon their location with respect to the Cu(II) d(x(2)-y(2)) orbital. A systematic study of DFT functionals and basis sets was undertaken to examine the ability to reproduce the experimentally determined spin Hamiltonian parameters. Inclusion of spin-orbit coupling (SOC) using MAG-ReSpect or ORCA with a BHLYP/IGLO-II Wachters setup with SOC corrections and ∼38% Hartree-Fock exchange gave the best predictions of the g and A((63)Cu) matrices. DFT calculations of the (14)N hyperfine and quadrupole parameters for the distal nitrogens of the coordinated heterocyclic

  18. Atomic-level insights into metabolite recognition and specificity of the SAM-II riboswitch.

    PubMed

    Doshi, Urmi; Kelley, Jennifer M; Hamelberg, Donald

    2012-02-01

    Although S-adenosylhomocysteine (SAH), a metabolic by-product of S-adenosylmethionine (SAM), differs from SAM only by a single methyl group and an overall positive charge, SAH binds the SAM-II riboswitch with more than 1000-fold less affinity than SAM. Using atomistic molecular dynamics simulations, we investigated the molecular basis of such high selectivity in ligand recognition by SAM-II riboswitch. The biosynthesis of SAM exclusively generates the (S,S) stereoisomer, and (S,S)-SAM can spontaneously convert to the (R,S) form. We, therefore, also examined the effects of (R,S)-SAM binding to SAM-II and its potential biological function. We find that the unfavorable loss in entropy in SAM-II binding is greater for (S,S)- and (R,S)-SAM than SAH, which is compensated by stabilizing electrostatic interactions with the riboswitch. The positively charged sulfonium moiety on SAM acts as the crucial anchor point responsible for the formation of key ionic interactions as it fits favorably in the negatively charged binding pocket. In contrast, SAH, with its lone pair of electrons on the sulfur, experiences repulsion in the binding pocket of SAM-II and is enthalpically destabilized. In the presence of SAH, similar to the unbound riboswitch, the pseudoknot structure of SAM-II is not completely formed, thus exposing the Shine-Dalgarno sequence. Unlike SAM, this may further facilitate ribosomal assembly and translation initiation. Our analysis of the conformational ensemble sampled by SAM-II in the absence of ligands and when bound to SAM or SAH reveals that ligand binding follows a combination of conformational selection and induced-fit mechanisms.

  19. Atomic-level insights into metabolite recognition and specificity of the SAM-II riboswitch

    PubMed Central

    Doshi, Urmi; Kelley, Jennifer M.; Hamelberg, Donald

    2012-01-01

    Although S-adenosylhomocysteine (SAH), a metabolic by-product of S-adenosylmethionine (SAM), differs from SAM only by a single methyl group and an overall positive charge, SAH binds the SAM-II riboswitch with more than 1000-fold less affinity than SAM. Using atomistic molecular dynamics simulations, we investigated the molecular basis of such high selectivity in ligand recognition by SAM-II riboswitch. The biosynthesis of SAM exclusively generates the (S,S) stereoisomer, and (S,S)-SAM can spontaneously convert to the (R,S) form. We, therefore, also examined the effects of (R,S)-SAM binding to SAM-II and its potential biological function. We find that the unfavorable loss in entropy in SAM-II binding is greater for (S,S)- and (R,S)-SAM than SAH, which is compensated by stabilizing electrostatic interactions with the riboswitch. The positively charged sulfonium moiety on SAM acts as the crucial anchor point responsible for the formation of key ionic interactions as it fits favorably in the negatively charged binding pocket. In contrast, SAH, with its lone pair of electrons on the sulfur, experiences repulsion in the binding pocket of SAM-II and is enthalpically destabilized. In the presence of SAH, similar to the unbound riboswitch, the pseudoknot structure of SAM-II is not completely formed, thus exposing the Shine-Dalgarno sequence. Unlike SAM, this may further facilitate ribosomal assembly and translation initiation. Our analysis of the conformational ensemble sampled by SAM-II in the absence of ligands and when bound to SAM or SAH reveals that ligand binding follows a combination of conformational selection and induced-fit mechanisms. PMID:22194311

  20. First Insight into the Genotypic Diversity of Clinical Mycobacterium tuberculosis Isolates from Gansu Province, China

    PubMed Central

    Liu, Jiao; Jiang, Yuan; Zhao, Xiuqin; Zhang, Yuanyuan; Liu, Haican; Lu, Bing; Wan, Kanglin

    2014-01-01

    Background Investigations of Mycobacterium tuberculosis genetic diversity in China have indicated a significant regional distribution. The aim of this study was to characterize the genotypes of clinical M. tuberculosis isolates obtained from Gansu, which has a special geographic location in China. Methodology/Principal Findings A total of 467 clinical M. tuberculosis strains isolated in Gansu Province were genotyped by 15-locus mycobacterial interspersed repetitive units–variable number tandem repeats (MIRU-VNTR) and spoligotyping. The results showed that 445 isolates belonged to six known spoligotype lineages, whereas 22 isolates were unknown. The Beijing genotype was the most prevalent (87.58%, n = 409), while the shared type 1 was the dominant genotype (80.94%, n = 378). The second most common lineage was the T lineage, with 25 isolates (5.35%), followed by the H lineage with 5 isolates (1.07%), the MANU family (0.64%, 3 isolates), the U family (0.43%, 2 isolates) and the CAS lineage with 1 isolate (0.21%). By using the VNTR15China method, we observed 15 groups and 228 genotypes among the 467 isolates. We found no association between the five larger groups (including the Beijing genotype) and sex, age, or treatment status, and there was no noticeable difference in the group analysis in different areas. In the present study, seven of the 15 MIRU-VNTR loci were highly or moderately discriminative according to their Hunter-Gaston discriminatory index. Conclusions/Significance The Beijing genotype is the predominant genotype in Gansu province. We confirm that VNTR15China is suitable for typing Beijing strains in China and that it has a better discriminatory power than spoligotyping. Therefore, the use of both methods is the most suitable for genotyping analysis of M. tuberculosis. PMID:24911588

  1. [Amyloidosis of familial Mediterranean fever (FMF)--insights to FMF phenotype II].

    PubMed

    Livneh, Avi

    2006-10-01

    Amyloidosis is the most grievous manifestation of Familial Mediterranean Fever (FMF), occurring in a high proportion of untreated patients. Continuously elevated serum amyloid A (SAA) levels during remissions, rather than a pulsatile rise during FMF attacks, underlies the development of amyloidosis. FMF phenotype II is one extreme of AA amyloidosis, evolving despite a complete absence of FMF attacks. FMF phenotype II is diagnosed in patients with AA amyloidosis in the context of a family history of FMF. In these patients and in patients with AA amyloidosis without family history of FMF and with unknown precipitating disease, MEFV gene analysis is mandatory. Moreover, since FMF phenotype II is an actual hazard, a cost-benefit analysis suggests that MEFV mutation determination in all first-degree family members of FMF patients is warranted, as it will significantly reduce future patient treatment costs.

  2. Low Mitochondrial DNA Diversity in an Ancient Population from China: Insight into Social Organization at the Fujia Site.

    PubMed

    Dong, Yu; Li, Chunxiang; Luan, Fengshi; Li, Zhenguang; Li, Hongjie; Cui, Yinqiu; Zhou, Hui; Malhi, Ripan S

    2015-01-01

    To gain insight into the social organization of a population associated with the Dawenkou period, we performed ancient DNA analysis of 18 individuals from human remains from the Fujia site in Shandong Province, China. Directly radiocarbon dated to 4800-4500 cal BP, the Fujia site is assumed to be associated with a transitional phase from matrilineal clans to patrilineal monogamous families. Our results reveal a low mitochondrial DNA diversity from the site and population. Combined with Y chromosome data, the pattern observed at the Fujia site is most consistent with a matrilineal community. The patterns also suggest that the bond of marriage was de-emphasized compared with the bonds of descent at Fujia.

  3. Application of ICHD-II Criteria in a Headache Clinic of China

    PubMed Central

    Dong, Zhao; Di, Hai; Dai, Wei; Liang, Jingyao; Pan, Meiyan; Zhang, Mingjie; Zhou, Zhibin; Li, Zheng; Liu, Ruozhuo; Yu, Shengyuan

    2012-01-01

    Background China has the huge map and the largest population in the world. Previous studies on the prevalence and classification of headaches were conducted based on the general population, however, similar studies among the Chinese outpatient population are scarce. This study aimed to analyze the characteristics of 1843 headache patients enrolled in a North China headache clinic of the General Hospital for Chinese People's Liberation Army from October 2011 to May 2012, with the International Classification of Headache Disorders, 2nd Edition (ICHD-II). Methods and Results Personal interviews were carried out and a detailed questionnaire was used to collect medical records including age, sex and headache characteristics. Patients came from 28 regions of China with the median age of 40.9 (9–80) years and the female/male ratio of 1.67/1. The primary headaches (78.4%) were classified as the following: migraine (39.1%), tension-type headache (32.5%), trigeminal autonomic cephalalgias (5.3%) and other primary headache (1.5%). Among the rest patients, 12.9% were secondary headaches, 5.9% were cranial neuralgias and 2.5% were unspecified or not elsewhere classified. Fourteen point nine percent (275/1843) were given an additional diagnosis of chronic daily headache, including medication-overuse headache (MOH, 49.5%), chronic tension-type headache (CTTH, 32.7%) and chronic migraine (CM, 13.5%). The visual analogue scale (VAS) score of TTH with MOH was significantly higher than that of CTTH (6.8±2.0 vs 5.6±2.0, P<0.001). The similar result was also observed in VAS score between migraine with MOH and CM (8.0±1.5 vs 7.0±1.5, P = 0.004). The peak age at onset of TTH for male and female were both in the 3rd decade of life. However, the age distribution at onset of migraine shows an obvious sex difference, i.e. the 2nd decade for females and the 1st decade for males. Conclusions/Significance This study revealed the characteristics of the headache clinic outpatients in a

  4. New Insights on Signal Propagation by Sensory Rhodopsin II/Transducer Complex

    PubMed Central

    Ishchenko, A.; Round, E.; Borshchevskiy, V.; Grudinin, S.; Gushchin, I.; Klare, J. P.; Remeeva, A.; Polovinkin, V.; Utrobin, P.; Balandin, T.; Engelhard, M.; Büldt, G.; Gordeliy, V.

    2017-01-01

    The complex of two membrane proteins, sensory rhodopsin II (NpSRII) with its cognate transducer (NpHtrII), mediates negative phototaxis in halobacteria N. pharaonis. Upon light activation NpSRII triggers a signal transduction chain homologous to the two-component system in eubacterial chemotaxis. Here we report on crystal structures of the ground and active M-state of the complex in the space group I212121. We demonstrate that the relative orientation of symmetrical parts of the dimer is parallel (“U”-shaped) contrary to the gusset-like (“V”-shaped) form of the previously reported structures of the NpSRII/NpHtrII complex in the space group P21212, although the structures of the monomers taken individually are nearly the same. Computer modeling of the HAMP domain in the obtained “V”- and “U”-shaped structures revealed that only the “U”-shaped conformation allows for tight interactions of the receptor with the HAMP domain. This is in line with existing data and supports biological relevance of the “U” shape in the ground state. We suggest that the “V”-shaped structure may correspond to the active state of the complex and transition from the “U” to the “V”-shape of the receptor-transducer complex can be involved in signal transduction from the receptor to the signaling domain of NpHtrII. PMID:28165484

  5. Interaction of copper (II) complexes by bovine serum albumin: spectroscopic and calorimetric insights.

    PubMed

    Singh, Namrata; Pagariya, Darshana; Jain, Surbhi; Naik, Sunil; Kishore, Nand

    2017-07-28

    Serum albumins being the most abundant proteins in the blood and cerebrospinal fluid are significant carriers of essential transition metal ions in the human body. Studies of copper (II) complexes have gained attention because of their potential applications in synthetic, biological, and industrial processes. Study of binding interactions of such bioinorganic complexes with serum albumins improves our understanding of biomolecular recognition process essential for rational drug design. In the present investigation, we have applied quantitative approach to explore interactions of novel synthesized copper (II) complexes viz. [Cu(L(1))(L(2))ClO4] (complex I), [Cu(L(2))(L(3))]ClO4] (complex II) and [Cu(L(4))2(H2O)2] (complex III) with bovine serum albumin (BSA) to evaluate their binding characteristics, site and mode of interaction. The fluorescence quenching of BSA initiated by complexation has been observed to be static in nature. The binding interactions are endothermic driven by entropic factors as confirmed by high sensitivity isothermal titration calorimetry. Changes in secondary and tertiary structure of protein have been studied by circular dichroism and significant reduction in α-helical content of BSA was observed upon binding. Site marking experiments with warfarin and ibuprofen indicated that copper complexes bind at site II of the protein.

  6. The new chemical insight for understanding the mechanism of Henry reaction over Cu(II) catalyst

    NASA Astrophysics Data System (ADS)

    Chen, Zhe-Ning; Wang, Kangli; Cui, Deng; Wu, Anan

    2017-04-01

    In this work, we present an alternative mechanism without the initial coordination of reactant and catalyst for the asymmetric Henry reaction over Cu(II) catalyst. Our calculations show that the re-coordination of acetate and Cu center is essential for the enantioselectivity. Thus, any effect of the re-coordination process would affect the enantioselectivity for this reaction.

  7. Crystal structure of human cytosolic 5'-nucleotidase II: insights into allosteric regulation and substrate recognition.

    PubMed

    Walldén, Karin; Stenmark, Pål; Nyman, Tomas; Flodin, Susanne; Gräslund, Susanne; Loppnau, Peter; Bianchi, Vera; Nordlund, Pär

    2007-06-15

    Cytosolic 5'-nucleotidase II catalyzes the dephosphorylation of 6-hydroxypurine nucleoside 5'-monophosphates and regulates the IMP and GMP pools within the cell. It possesses phosphotransferase activity and thereby also catalyzes the reverse reaction. Both reactions are allosterically activated by adenine-based nucleotides and 2,3-bisphosphoglycerate. We have solved structures of cytosolic 5'-nucleotidase II as native protein (2.2 Angstrom) and in complex with adenosine (1.5 Angstrom) and beryllium trifluoride (2.15 Angstrom) The tetrameric enzyme is structurally similar to enzymes of the haloacid dehalogenase (HAD) superfamily, including mitochondrial 5'(3')-deoxyribonucleotidase and cytosolic 5'-nucleotidase III but possesses additional regulatory regions that contain two allosteric effector sites. At effector site 1 located near a subunit interface we modeled diadenosine tetraphosphate with one adenosine moiety in each subunit. This efficiently glues the tetramer subunits together in pairs. The model shows why diadenosine tetraphosphate but not diadenosine triphosphate activates the enzyme and supports a role for cN-II during apoptosis when the level of diadenosine tetraphosphate increases. We have also modeled 2,3-bisphosphoglycerate in effector site 1 using one phosphate site from each subunit. By comparing the structure of cytosolic 5'-nucleotidase II with that of mitochondrial 5'(3')-deoxyribonucleotidase in complex with dGMP, we identified residues involved in substrate recognition.

  8. Biochemical and structural characterization of Salmonella typhimurium glyoxalase II: new insights into metal ion selectivity.

    PubMed

    Campos-Bermudez, Valeria A; Leite, Ney Ribeiro; Krog, Renata; Costa-Filho, Antonio J; Soncini, Fernando C; Oliva, Glaucius; Vila, Alejandro J

    2007-10-02

    Glyoxalase II is a hydrolytic enzyme part of the glyoxalase system, responsible for detoxifying several cytotoxic compounds employing glutathione. Glyoxalase II belongs to the superfamily of metallo-beta-lactamases, with a conserved motif able to bind up to two metal ions in their active sites, generally zinc. Instead, several eukaryotic glyoxalases II have been characterized with different ratios of iron, zinc, and manganese ions. We have expressed a gene coding for a putative member of this enzyme superfamily from Salmonella typhimurium that we demonstrate, on the basis of its activity, to be a glyoxalase II, named GloB. Recombinant GloB expressed in Escherichia coli was purified with variable amounts of iron, zinc, and manganese. All forms display similar activities, as can be shown from protein expression in minimal medium supplemented with specific metal ions. The crystal structure of GloB solved at 1.4 A shows a protein fold and active site similar to those of its eukaryotic homologues. NMR and EPR experiments also reveal a conserved electronic structure at the metal site. GloB is therefore able to accommodate these different metal ions and to carry out the hydrolytic reaction with similar efficiencies in all cases. The metal promiscuity of this enzyme (in contrast to other members of the same superfamily) can be accounted for by the presence of a conserved Asp residue acting as a second-shell ligand that is expected to increase the hardness of the metal binding site, therefore favoring iron uptake in glyoxalases II.

  9. Emergence of Cryptosporidium hominis Monkey Genotype II and Novel Subtype Family Ik in the Squirrel Monkey (Saimiri sciureus) in China.

    PubMed

    Liu, Xuehan; Xie, Na; Li, Wei; Zhou, Ziyao; Zhong, Zhijun; Shen, Liuhong; Cao, Suizhong; Yu, Xingming; Hu, Yanchuan; Chen, Weigang; Peng, Gangneng

    2015-01-01

    A single Cryptosporidium isolate from a squirrel monkey with no clinical symptoms was obtained from a zoo in Ya'an city, China, and was genotyped by PCR amplification and DNA sequencing of the small-subunit ribosomal RNA (SSU rRNA), 70-kDa heat shock protein (HSP70), Cryptosporidium oocyst wall protein, and actin genes. This multilocus genetic characterization determined that the isolate was Cryptosporidium hominis, but carried 2, 10, and 6 nucleotide differences in the SSU rRNA, HSP70, and actin loci, respectively, which is comparable to the variations at these loci between C. hominis and the previously reported monkey genotype (2, 3, and 3 nucleotide differences). Phylogenetic studies, based on neighbor-joining and maximum likelihood methods, showed that the isolate identified in the current study had a distinctly discordant taxonomic status, distinct from known C. hominis and also from the monkey genotype, with respect to the three loci. Restriction fragment length polymorphisms of the SSU rRNA gene obtained from this study were similar to those of known C. hominis but clearly differentiated from the monkey genotype. Further subtyping was performed by sequence analysis of the gene encoding the 60-kDa glycoprotein (gp60). Maximum homology of only 88.3% to C. hominis subtype IdA10G4 was observed for the current isolate, and phylogenetic analysis demonstrated that this particular isolate belonged to a novel C. hominis subtype family, IkA7G4. This study is the first to report C. hominis infection in the squirrel monkey and, based on the observed genetic characteristics, confirms a new C. hominis genotype, monkey genotype II. Thus, these results provide novel insights into genotypic variation in C. hominis.

  10. Emergence of Cryptosporidium hominis Monkey Genotype II and Novel Subtype Family Ik in the Squirrel Monkey (Saimiri sciureus) in China

    PubMed Central

    Zhou, Ziyao; Zhong, Zhijun; Shen, Liuhong; Cao, Suizhong; Yu, Xingming; Hu, Yanchuan; Chen, Weigang; Peng, Gangneng

    2015-01-01

    A single Cryptosporidium isolate from a squirrel monkey with no clinical symptoms was obtained from a zoo in Ya’an city, China, and was genotyped by PCR amplification and DNA sequencing of the small-subunit ribosomal RNA (SSU rRNA), 70-kDa heat shock protein (HSP70), Cryptosporidium oocyst wall protein, and actin genes. This multilocus genetic characterization determined that the isolate was Cryptosporidium hominis, but carried 2, 10, and 6 nucleotide differences in the SSU rRNA, HSP70, and actin loci, respectively, which is comparable to the variations at these loci between C. hominis and the previously reported monkey genotype (2, 3, and 3 nucleotide differences). Phylogenetic studies, based on neighbor-joining and maximum likelihood methods, showed that the isolate identified in the current study had a distinctly discordant taxonomic status, distinct from known C. hominis and also from the monkey genotype, with respect to the three loci. Restriction fragment length polymorphisms of the SSU rRNA gene obtained from this study were similar to those of known C. hominis but clearly differentiated from the monkey genotype. Further subtyping was performed by sequence analysis of the gene encoding the 60-kDa glycoprotein (gp60). Maximum homology of only 88.3% to C. hominis subtype IdA10G4 was observed for the current isolate, and phylogenetic analysis demonstrated that this particular isolate belonged to a novel C. hominis subtype family, IkA7G4. This study is the first to report C. hominis infection in the squirrel monkey and, based on the observed genetic characteristics, confirms a new C. hominis genotype, monkey genotype II. Thus, these results provide novel insights into genotypic variation in C. hominis. PMID:26509708

  11. Principles of ion recognition in RNA: insights from the group II intron structures.

    PubMed

    Marcia, Marco; Pyle, Anna Marie

    2014-04-01

    Metal ions promote both RNA folding and catalysis, thus being essential in stabilizing the structure and determining the function of large RNA molecules, including group II introns. The latter are self-splicing metalloribozymes, containing a heteronuclear four-metal-ion center within the active site. In addition to these catalytic ions, group II introns bind many other structural ions, including delocalized ions that bind the RNA diffusively and well-ordered ions that bind the RNA tightly with high occupancy. The latter ions, which can be studied by biophysical methods, have not yet been analyzed systematically. Here, we compare crystal structures of the group IIC intron from Oceanobacillus iheyensis and classify numerous site-bound ions, which are primarily localized in the intron core and near long-range tertiary contacts. Certain ion-binding sites resemble motifs observed in known RNA structures, while others are idiosyncratic to the group II intron. Particularly interesting are (1) ions proximal to the active site, which may participate in splicing together with the catalytic four-metal-ion center, (2) organic ions that bind regions predicted to interact with intron-encoded proteins, and (3) unusual monovalent ions bound to GU wobble pairs, GA mismatches, the S-turn, the tetraloop-receptor, and the T-loop. Our analysis extends the general principles by which ions participate in RNA structural organization and it will aid in the determination and interpretation of future RNA structures.

  12. Principles of ion recognition in RNA: insights from the group II intron structures

    PubMed Central

    Marcia, Marco; Pyle, Anna Marie

    2014-01-01

    Metal ions promote both RNA folding and catalysis, thus being essential in stabilizing the structure and determining the function of large RNA molecules, including group II introns. The latter are self-splicing metalloribozymes, containing a heteronuclear four-metal-ion center within the active site. In addition to these catalytic ions, group II introns bind many other structural ions, including delocalized ions that bind the RNA diffusively and well-ordered ions that bind the RNA tightly with high occupancy. The latter ions, which can be studied by biophysical methods, have not yet been analyzed systematically. Here, we compare crystal structures of the group IIC intron from Oceanobacillus iheyensis and classify numerous site-bound ions, which are primarily localized in the intron core and near long-range tertiary contacts. Certain ion-binding sites resemble motifs observed in known RNA structures, while others are idiosyncratic to the group II intron. Particularly interesting are (1) ions proximal to the active site, which may participate in splicing together with the catalytic four-metal-ion center, (2) organic ions that bind regions predicted to interact with intron-encoded proteins, and (3) unusual monovalent ions bound to GU wobble pairs, GA mismatches, the S-turn, the tetraloop-receptor, and the T-loop. Our analysis extends the general principles by which ions participate in RNA structural organization and it will aid in the determination and interpretation of future RNA structures. PMID:24570483

  13. Novel insights into enhanced dewaterability of waste activated sludge by Fe(II)-activated persulfate oxidation.

    PubMed

    Zhen, Guangyin; Lu, Xueqin; Li, Yuyou; Zhao, Youcai; Wang, Baoying; Song, Yu; Chai, Xiaoli; Niu, Dongjie; Cao, Xianyan

    2012-09-01

    The potential of Fe(II)-activated persulfate (S(2)O(8)(2-)) oxidation on enhancing the dewaterability of sludge flocs from 3-full scale wastewater treatment plants (WWTPs) were investigated. Normalized capillary suction time (CST) was applied to evaluate sludge dewaterability. Both extracellular polymeric substances (EPS) and metabolic activity of microorganisms were determined to explore the responsible mechanism. Fe(II)-S(2)O(8)(2-) oxidation effectively improved sludge dewaterability. The most important mechanisms were proposed to be the degradation of EPS incorporated in sludge flocs and rupture of microbial cells. Three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy confirmed that the powerful SO(4)(-) from Fe(II)-S(2)O(8)(2-) system destroyed the particular functional groups of fluorescing substances (i.e., aromatic protein-, tryptophan protein-, humic- and fulvic-like substances) in EPS and caused cleavage of linkages in the polymeric backbone and simultaneous destruction of microbial cells, resulting in the release of EPS-bound water, intracellular materials and water of hydration inside cells, and subsequent enhancement of dewaterability.

  14. Will China's Cooperative Medical System fail again? Insight from farmer satisfaction survey.

    PubMed

    Chen, Dong; Tang, Kam Ki; Zhao, Lifeng; Zhang, Yuhong

    2015-06-01

    This paper studied the sustainability of China's New Rural Cooperative Medical System (NCMS) by evaluating the satisfaction rate of its participants-the farmers. The study related the overall satisfaction of the farmers to their satisfaction with the four different aspects of the program. It also identified which personal and program attributes affect the farmers' satisfaction rate. Survey data of 1278 households from 66 counties in Shandong Province of China were collected in 2011 using a multi-stage stratified cluster-sampling method. To overcome the nepotistic barriers in rural China, field surveys in each township were conducted by university students from the same place. Data were analyzed using multiple regressions and structural equation modeling method. The results showed that 86% of the farmers were either satisfied or very satisfied with the NCMS and 82% indicated their intention to continue participating in the program. Aside from its financial benefits, both the publicity and reimbursement procedure of the program were found to be significant factors in influencing the satisfaction of the farmers. Majority of the participants held positive opinions toward the NCMS, contradicting the negative assessments made by many previous studies. Given the high proportion of farmers willing to continue with the program, it is likely to be sustainable in the near future. Greater publicity and education efforts should be made to make the farmers better informed about the program, and measures should be taken to improve its reimbursement procedure and the setting of the premium level. © The Author (2013). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Mesozoic lacewings from China provide phylogenetic insight into evolution of the Kalligrammatidae (Neuroptera)

    PubMed Central

    2014-01-01

    Background The Kalligrammatidae are distinctive, large, conspicuous, lacewings found in Eurasia from the Middle Jurassic to mid Early Cretaceous. Because of incomplete and often inadequate fossil preservation, an absence of detailed morphology, unclear relationships, and unknown evolutionary trends, the Kalligrammatidae are poorly understood. Results We describe three new subfamilies, four new genera, twelve new species and four unassigned species from the late Middle Jurassic Jiulongshan and mid Early Cretaceous Yixian Formations of China. These kalligrammatid taxa exhibit diverse morphological characters, such as mandibulate mouthparts in one major clade and siphonate mouthparts in the remaining four major clades, the presence or absence of a variety of distinctive wing markings such as stripes, wing spots and eyespots, as well as multiple major wing shapes. Based on phylogenetic analyses, the Kalligrammatidae are divided into five principal clades: Kalligrammatinae Handlirsch, 1906, Kallihemerobiinae Ren & Engel, 2008, Meioneurinae subfam. nov., Oregrammatinae subfam. nov. and Sophogrammatinae subfam. nov., each of which is accorded subfamily-level status. Our results show significant morphological and evolutionary differentiation of the Kalligrammatidae family during a 40 million-year-interval of the mid Mesozoic. Conclusion A new phylogeny and classification of five subfamilies and their constituent genera is proposed for the Kalligrammatidae. These diverse, yet highly specialized taxa from northeastern China suggest that eastern Eurasia likely was an important diversification center for the Kalligrammatidae. Kalligrammatids possess an extraordinary morphological breadth and panoply of adaptations during the mid-Mesozoic that highlight our conclusion that their evolutionary biology is much more complex than heretofore realized. PMID:24912379

  16. Propagated rifting in the Southwest Sub-basin, South China Sea: Insights from analogue modelling

    NASA Astrophysics Data System (ADS)

    Ding, Weiwei; Li, Jiabiao

    2016-10-01

    How the South China Sea rifted has long been a puzzling question that is still debated, particularly with reference to the Southwest Sub-basin (SWSB). Analogue modelling remains one of the most useful tools for testing rift models and processes. Here, we present and discuss a series of analogue modelling experiments designed to investigate the rifting process of the SWSB. Convincing geophysical results were compiled to provide realistic constraints to test the experimental results and interpretations. A heterogeneous lithosphere model with a varied lithospheric structure showed tectono-morphological features similar to the natural case of the SWSB, indicating that the initial thermal condition and rheological stratification of the lithosphere should have a dominant effect on the rifting process of the SWSB. Rigid tectonic blocks existed in the continental margin, such as the Macclesfield Bank and the Reed Bank, and they played important roles in both the shaping of the continent-ocean boundary and the coupling between the crust and mantle. The initial thermal condition and rheological stratification of the lithosphere under the South China Sea controlled the propagated rifting process of the SWSB. Extension was centred on the deep troughs between the rigid blocks, and the break-up occurred in these areas between them. The westward rifting propagation is best explained with a heterogeneous lithosphere model characterized by varied lithospheric structure, and it was responsible for producing the V-shaped configuration of the SWSB.

  17. Reactivation and mantle dynamics of North China Craton: insight from P-wave anisotropy tomography

    NASA Astrophysics Data System (ADS)

    Tian, You; Zhao, Dapeng

    2013-12-01

    We determined the first 3-D P-wave anisotropic tomography beneath the North China Craton (NCC) using a large number of high-quality arrival-time data from local earthquakes and teleseismic events, which reveals depth-dependent azimuthal anisotropy in the crust and upper mantle down to 600 km depth. In the NCC western block, the fast velocity direction (FVD) varies from east-west in the southern part to northeast-southwest in the northern part, which may reflect either the interaction between the Yangtze block and NCC or fossil lithospheric fabrics in the craton. Under the NCC eastern block, a uniform northwest-southeast FVD is revealed in the lower part of the upper mantle (300-410 km depths) and the mantle transition zone (410-660 km depths), which may reflect horizontal and upwelling flows in the big mantle wedge (BMW) above the stagnant Pacific slab in the mantle transition zone. The NCC central block exhibits a northeast-southwest FVD, consistent with the surface tectonic orientation there, suggesting that the cold and thick (>300 km) cratonic root of the NCC western block may obstruct the northwest-southeast trending mantle flow induced by the Pacific Plate subduction, resulting in a northeast-southwest trending mantle flow under the central block. Our present results indicate that the corner flow in the BMW associated with the deep subduction of the Pacific Plate is the main cause of NCC reactivation and mantle dynamics under East China.

  18. Recent insights into the epidemiology and genetics of Ascaris in China using molecular tools.

    PubMed

    Peng, W; Yuan, K; Hu, M; Gasser, R B

    2007-03-01

    Ascaris is a large parasitic roundworm (nematode) of the small intestine of humans and pigs, which causes the socio-economically important disease, ascariasis. To better understand the relationship of Ascaris between the 2 host species, recent studies in China have focused on investigating the genetics and epidemiology of Ascaris from humans and pigs using a mutation scanning-based approach. Findings provided support for a low level of gene flow between the human and porcine Ascaris populations. Extending the studies of genotypic variability within Ascaris from humans and pigs, experimental infections of mice and pigs with selected genotypes of Ascaris were carried out. Initial results indicate that there is a significant difference in the ability of Ascaris eggs of genotype G1 (derived from human) and G3 (derived from pig) to infect and establish as adults in pigs, supporting the difference in the frequencies of these genotypes in natural Ascaris populations between pigs and humans in China. Taken together, current information supports that there is limited cross-infection of Ascaris between humans and pigs in endemic regions and that pigs are not a significant reservoir of human infection with the adult nematode in such areas.

  19. Mesozoic lacewings from China provide phylogenetic insight into evolution of the Kalligrammatidae (Neuroptera).

    PubMed

    Yang, Qiang; Wang, Yongjie; Labandeira, Conrad C; Shih, Chungkun; Ren, Dong

    2014-06-09

    The Kalligrammatidae are distinctive, large, conspicuous, lacewings found in Eurasia from the Middle Jurassic to mid Early Cretaceous. Because of incomplete and often inadequate fossil preservation, an absence of detailed morphology, unclear relationships, and unknown evolutionary trends, the Kalligrammatidae are poorly understood. We describe three new subfamilies, four new genera, twelve new species and four unassigned species from the late Middle Jurassic Jiulongshan and mid Early Cretaceous Yixian Formations of China. These kalligrammatid taxa exhibit diverse morphological characters, such as mandibulate mouthparts in one major clade and siphonate mouthparts in the remaining four major clades, the presence or absence of a variety of distinctive wing markings such as stripes, wing spots and eyespots, as well as multiple major wing shapes. Based on phylogenetic analyses, the Kalligrammatidae are divided into five principal clades: Kalligrammatinae Handlirsch, 1906, Kallihemerobiinae Ren & Engel, 2008, Meioneurinae subfam. nov., Oregrammatinae subfam. nov. and Sophogrammatinae subfam. nov., each of which is accorded subfamily-level status. Our results show significant morphological and evolutionary differentiation of the Kalligrammatidae family during a 40 million-year-interval of the mid Mesozoic. A new phylogeny and classification of five subfamilies and their constituent genera is proposed for the Kalligrammatidae. These diverse, yet highly specialized taxa from northeastern China suggest that eastern Eurasia likely was an important diversification center for the Kalligrammatidae. Kalligrammatids possess an extraordinary morphological breadth and panoply of adaptations during the mid-Mesozoic that highlight our conclusion that their evolutionary biology is much more complex than heretofore realized.

  20. Genetic insights into the disease mechanisms of type II mixed cryoglobulinemia induced by hepatitis C virus.

    PubMed

    De Re, V; Caggiari, L; De Vita, S; Mazzaro, C; Lenzi, M; Galli, M; Monti, G; Ferri, C; Zignego, A L; Gabrielli, A; Sansonno, D; Dammacco, F; Libra, M; Sacchi, N; Talamini, R; Spina, M; Cannizzaro, R; Guidoboni, M; Dolcetti, R

    2007-09-01

    The ability of the immune system to distinguish between self and non-self is critical to the functioning of the immune response. A breakdown in these mechanisms can lead to the onset of autoimmune disease. Clinical and molecular data suggest that shared immunogenetic mechanisms lead to the autoimmune process. The most studied part of the autoimmune process is the human leukocyte antigen (HLA) region. Recently, progress has been made in narrowing down HLA cluster classifications based on structural and functional features of HLA alleles. Using this approach we have investigated 175 patients with hepatitis C virus (HCV)-induced type II cryoglobulinemia (MC), and compared them to a control group of 14,923 bone marrow donors. Additionally, we investigated the frequency of HLA homozygosity in the same groups of subjects. Our results provide evidence of a role for DR5 and DQ3 HLA class II clusters and a higher frequency of HLA homozygous leading to the clinical outcome of type II mixed cryoglobulinemic autoimmune disease. The DR5 cluster is characterized by a Glu in beta 9 and its polymorphism is connected with preferred anchors at beta 9 of the binding peptide, while the DQ3 cluster is characterized by Glu B86 and Leu B87, which allows the binding of large hydrophobic amino acids at p1 of the binding peptide. The mechanisms by which variations in HLA lead to autoimmunity remain unknown, although they are likely to be mediated by continuous presentation of HCV epitopes to T cells and a genetic background that limits the effective clearance of HCV. The results presented in this paper have increased our knowledge of the mechanism of autoimmune disease and B-cell lymphoproliferation during HCV infection. The work was performed in accordance with the principles of the 1983 Declaration of Helsinki. There is no conflict of interest.

  1. Preoperative radiotherapy for inoperable stage II endometrial cancer: insights into improving treatment and outcomes.

    PubMed

    Lee, Marette H; Aquino-Parsons, Christina; Hoskins, Paul J; Lim, Peter; Kwon, Janice S

    2013-07-01

    To review recurrence patterns and survival outcomes of women receiving preoperative radiotherapy for clinical stage II endometrial cancer in British Columbia. We performed a retrospective population-based cohort study of all patients with clinical stage II endometrial cancer who were referred to the British Columbia Cancer Agency from 2000 to 2008, deemed ineligible for primary surgery, and therefore offered preoperative radiotherapy followed by surgery. Patient demographics, uterine risk factors, timing and details of treatments, and timing and sites of recurrence were obtained from patient records. Primary outcome measures were the sites and rates of recurrence and recurrence-free survival. We identified 29 patients with a mean age of 61 years (range 41 to 83) and median follow-up of 3.1 years (range 0.3 to 5.3). Three-year overall survival was 79%, and median recurrence-free survival was 2.5 years. Eight patients had recurrence of disease (27.6%), with a median time to recurrence of 1.3 years, (range 0.4 to 2.7). Six of these eight women had two or more high-risk uterine factors (deep myometrial invasion, grade 3 tumour), ovarian involvement, or adverse histological type (carcinosarcoma), compared with only one of 21 patients without recurrence. Seven of eight women had recurrence outside the radiated volume of tissue. Median survival after recurrence was 1.0 years (range 0.4 to 2.2). Women with clinical stage II endometrial cancer had a significant risk of recurrence when treated with preoperative radiotherapy followed by surgery. They were more likely to have distant recurrences, implying the need for an alternate treatment paradigm.

  2. Metagenomic insights into Fe(II)-oxidizing Zetaproteobacteria from a biomat at Loi'hi, Hawai'i

    NASA Astrophysics Data System (ADS)

    Singer, E.; Dhillon, A.; Barco, R. A.; Edwards, K. J.

    2011-12-01

    transport, CO2 fixation, and pili assembly, signal transduction and response regulation, oxygen sensation and detoxification, and heavy metal resistance. All of these genes have homologs in PV-1 and are assumed to be partially responsible for the dominance of the Zetaproteobacteria at the Loihi Seamount and other deep-sea hydrothermal vents, where biological Fe(II)-oxidation is possible (Singer et al., submitted). This study provides novel insights into the genomic backbone of a dominant and ubiquitous Zetaproteobacteria organism, which may globally influence the iron and carbon cycles in deep-sea environments.

  3. Microseismic Monitoring of Strainburst Activities in Deep Tunnels at the Jinping II Hydropower Station, China

    NASA Astrophysics Data System (ADS)

    Xu, N. W.; Li, T. B.; Dai, F.; Zhang, R.; Tang, C. A.; Tang, L. X.

    2016-03-01

    Rockbursts were frequently encountered during the construction of deep tunnels at the Jinping II hydropower station, Southwest China. Investigations of the possibility of rockbursts during tunnel boring machine (TBM) and drilling and blasting (D&B) advancement are necessary to guide the construction of tunnels and to protect personnel and TBM equipment from strainburst-related accidents. A real-time, movable microseismic monitoring system was installed to forecast strainburst locations ahead of the tunnel faces. The spatiotemporal distribution evolution of microseismic events prior to and during strainbursts was recorded and analysed. The concentration of microseismic events prior to the occurrence of strainbursts was found to be a significant precursor to strainbursts in deep rock tunnelling. During a 2-year microseismic investigation of strainbursts in the deep tunnels at the Jinping II hydropower station, a total of 2240 strainburst location forecasts were issued, with 63 % correctly forecasting the locations of strainbursts. The successful forecasting of strainburst locations proved that microseismic monitoring is essential for the assessment and mitigation of strainburst hazards, and can be used to minimise damage to equipment and personnel. The results of the current study may be valuable for the construction management and safety assessment of similar underground rock structures under high in situ stress.

  4. Substrate promiscuity in DNA methyltransferase M.PvuII. A mechanistic insight.

    PubMed

    Aranda, Juan; Roca, Maite; Tuñón, Iñaki

    2012-07-28

    M.PvuII is a DNA methyltransferase from the bacterium Proteus vulgaris that catalyzes methylation of cytosine at the N4 position. This enzyme also displays promiscuous activity catalyzing methylation of adenine at the N6 position. In this work we use QM/MM methods to investigate the reaction mechanism of this promiscuous activity. We found that N6 methylation in M.PvuII takes place by means of a stepwise mechanism in which deprotonation of the exocyclic amino group is followed by the methyl transfer. Deprotonation involves two residues of the active site, Ser53 and Asp96, while methylation takes place directly from the AdoMet cofactor to the target nitrogen atom. The same reaction mechanism was described for cytosine methylation in the same enzyme, while the reversal timing, that is methylation followed by deprotonation, has been described in M.TaqI, an enzyme that catalyzes the N6-adenine DNA methylation from Thermus aquaticus. These mechanistic findings can be useful to understand the evolutionary paths followed by N-methyltransferases.

  5. Structural and functional insight into TAF1-TAF7, a subcomplex of transcription factor II D

    SciTech Connect

    Bhattacharya, Suparna; Lou, Xiaohua; Hwang, Peter; Rajashankar, Kanagalaghatta R.; Wang, Xiaoping; Gustafsson, Jan-Åke; Fletterick, Robert J.; Jacobson, Raymond H.; Webb, Paul

    2014-07-01

    Transcription factor II D (TFIID) is a multiprotein complex that nucleates formation of the basal transcription machinery. TATA binding protein-associated factors 1 and 7 (TAF1 and TAF7), two subunits of TFIID, are integral to the regulation of eukaryotic transcription initiation and play key roles in preinitiation complex (PIC) assembly. Current models suggest that TAF7 acts as a dissociable inhibitor of TAF1 histone acetyltransferase activity and that this event ensures appropriate assembly of the RNA polymerase II-mediated PIC before transcriptional initiation. Here, we report the 3D structure of a complex of yeast TAF1 with TAF7 at 2.9 Å resolution. The structure displays novel architecture and is characterized by a large predominantly hydrophobic heterodimer interface and extensive cofolding of TAF subunits. There are no obvious similarities between TAF1 and known histone acetyltransferases. Instead, the surface of the TAF1–TAF7 complex contains two prominent conserved surface pockets, one of which binds selectively to an inhibitory trimethylated histone H3 mark on Lys27 in a manner that is also regulated by phosphorylation at the neighboring H3 serine. Our findings could point toward novel roles for the TAF1–TAF7 complex in regulation of PIC assembly via reading epigenetic histone marks.

  6. Late Cenozoic evolution of the East China continental margin: Insights from seismic, gravity, and magnetic analyses

    NASA Astrophysics Data System (ADS)

    Shang, Lu-Ning; Zhang, Xun-Hua; Jia, Yong-Gang; Han, Bo; Yang, Chuan-Sheng; Geng, Wei; Pang, Yu-Mao

    2017-02-01

    Seismic reflection profiles reveal the structural characteristics beneath the East China Sea shelf margin and the Okinawa Trough, and provide new constraints on the Late Cenozoic evolution of the East China continental margin. The Frontal Shelf Basin between the Taiwan-Sinzi Uplift and the trough axis occupies the western half of the Northern-Middle Okinawa Trough. In this basin, the Middle-Late Miocene sediments are confined to grabens or half-grabens dominated by listric faults, whereas the overlying Pliocene-Quaternary sequence is characterized by a uniform thickness and dense planar-type faults, suggesting that rifting of the Northern-Middle Okinawa Trough initiated during the Middle Miocene but slowed down during the earliest Pliocene. Since that time, the opening of the Okinawa Trough has been dominated by diffuse rifting. The Southern Okinawa Trough is predominately filled by Quaternary sediments, indicating that its back-arc rifting began during the earliest Pleistocene. Contractional structures identified in the pre-Quaternary sequence beneath the continental slope, along with an erosional Pleistocene-pre-Pleistocene unconformity in the Southern Okinawa Trough, demonstrate the existence of pre-rifting compression and uplifting in this region. We use this evidence and previously published results, to propose an evolutionary model of the East China continental margin during the Late Cenozoic. The Northern-Middle Okinawa Trough began rifting during the Middle Miocene on a paleo-uplift. The Luzon Arc initially impinged upon the Eurasian continental margin during the Late Miocene near the southeastern end of the Miyako Fault Belt and activated the proto-Taiwan Orogeny in today's Southern Okinawa Trough and adjacent regions. During the Late Miocene-Pliocene, the orogeny quickly propagated southwestward along with the west-northwest-moving Philippine Sea Plate. Subsequently, the rifting of the Southern Okinawa Trough was initiated during the earliest Pleistocene

  7. Neoarchean tectonics: Insight from the Baijiafen ductile shear zone, eastern Anshan, Liaoning Province, NE China

    NASA Astrophysics Data System (ADS)

    Li, Jing; Liu, Yong-Jiang; Jin, Wei; Li, Xian-Hua; Neubauer, Franz; Li, Wei-Min; Liang, Chen-Yue; Wen, Quan-Bo; Zhang, Yuan-Yuan

    2017-05-01

    The North China Craton is one of the major Archean to Paleoproterozoic cratons in the world and oldest craton in China, which preserves a large amount of ancient basement and abundant structures showing the early earth tectonics. The controversy over the Archean tectonic regimes has lasted several decades centering around horizontal and vertical tectonics, the two classical tectonic models for Archean times. Thus, more studies of the early crustal growth and tectonic evolution are requisite for better understanding geodynamic regimes in the early Precambrian. This study provides an example for revealing of Archean tectonics. The NWN-trending, ENE-dipping Baijiafen ductile shear zone is located in the eastern Anshan of the northeastern North China Craton and mainly comprises two types of gneisses, including the Chentaigou porphyritic granitic gneiss and the Baijiafen trondhjemitic gneiss. In this study, we have carried out a detailed study on the macrostructure, microstructure and fabric characteristics of the two main types of deformed gneisses within the shear zone. The ribbon structures formed by intensely elongated quartz grains are widespread in these gneisses. Well-developed mineral stretching lineations and asymmetric fabrics indicate an ESE-directed downward shearing. The quartz c-axis fabric patterns obtained by electron backscatter diffraction technique imply low to middle temperature non-coaxial deformation with active rhomb slip and basal slip. Deformation behaviors of minerals and quartz crystallographic preferred orientations demonstrate that the rocks underwent mylonitization at a temperature of 400-500 °C under greenschist facies metamorphic conditions. Dislocation creep is the main rock deformation mechanism within the shear zone. Finite strain measurement results suggest that the strain types of the shear zone are generally related to elongate-plane deformation, and the tectonites change from L-S- to LS-type across the shear zone. The

  8. Ecosystem Services Insights into Water Resources Management in China: A Case of Xi’an City

    PubMed Central

    Liu, Jingya; Li, Jing; Gao, Ziyi; Yang, Min; Qin, Keyu; Yang, Xiaonan

    2016-01-01

    Global climate and environmental changes are endangering global water resources; and several approaches have been tested to manage and reduce the pressure on these decreasing resources. This study uses the case study of Xi’an City in China to test reasonable and effective methods to address water resource shortages. The study generated a framework combining ecosystem services and water resource management. Seven ecosystem indicators were classified as supply services, regulating services, or cultural services. Index values for each indicator were calculated, and based on questionnaire results, each index’s weight was calculated. Using the Likert method, we calculated ecosystem service supplies in every region of the city. We found that the ecosystem’s service capability is closely related to water resources, providing a method for managing water resources. Using Xi’an City as an example, we apply the ecosystem services concept to water resources management, providing a method for decision makers. PMID:27886137

  9. Ecosystem Services Insights into Water Resources Management in China: A Case of Xi'an City.

    PubMed

    Liu, Jingya; Li, Jing; Gao, Ziyi; Yang, Min; Qin, Keyu; Yang, Xiaonan

    2016-11-24

    Global climate and environmental changes are endangering global water resources; and several approaches have been tested to manage and reduce the pressure on these decreasing resources. This study uses the case study of Xi'an City in China to test reasonable and effective methods to address water resource shortages. The study generated a framework combining ecosystem services and water resource management. Seven ecosystem indicators were classified as supply services, regulating services, or cultural services. Index values for each indicator were calculated, and based on questionnaire results, each index's weight was calculated. Using the Likert method, we calculated ecosystem service supplies in every region of the city. We found that the ecosystem's service capability is closely related to water resources, providing a method for managing water resources. Using Xi'an City as an example, we apply the ecosystem services concept to water resources management, providing a method for decision makers.

  10. Molecular insights of genetic variation in Erianthus arundinaceus populations native to China.

    PubMed

    Zhang, Jianbo; Yan, Jiajun; Zhang, Yunwei; Ma, Xiao; Bai, Shiqie; Wu, Yanqi; Dao, Zhixue; Li, Daxu; Zhang, Changbing; Zhang, Yu; You, Minghong; Yang, Fuyu; Zhang, Jin

    2013-01-01

    E. arundinaceus (Retz.) Jeswiet is a warm-season, tall-growing perennial species native to much southern portion in China. The grass has been extensively used in sugarcane breeding and is recently targeted as a bioenergy feedstock crop. However, information on the genetic structure of the Chinese wild germplasm is limited. Knowledge of genetic variation within and among populations is essential for breeding new cultivars in the species. The major objective of this study was to quantify the magnitude of genetic variation among and within natural populations in China. In this experiment, we analyzed genetic variation of 164 individuals of 18 populations collected from natural habitats in six Chinese provinces using 20 sequence-related amplified polymorphism (SRAP) primer pairs generating 277 polymorphic bands. Among and within the populations, the percentage of polymorphic bands (PPB) was 80.00% and 27.07%, genetic diversity (HE ) was 0.245 and 0.099, effective number of alleles (NE ) was 1.350 and 1.170, and Shannon's information index (I) was 0.340 and 0.147, respectively. The populations were clustered into six groups exhibiting a high level of genetic differentiation, which was highly associated with geographic origins of respective germplasm populations, but was not significantly associated with geographic distances between the populations. This is the first report indicating that large genetic variation exists in the Chinese E. arundinaceus germplasm based on the SRAP molecular marker analysis of native populations. The genetic structure of populations in the species has been substantially affected by geographic landforms and environments. The diverse collection will be highly valuable in genetic improvement in the species per se and likely in sugarcane.

  11. Molecular Insights of Genetic Variation in Erianthus arundinaceus Populations Native to China

    PubMed Central

    Bai, Shiqie; Wu, Yanqi; Dao, Zhixue; Li, Daxu; Zhang, Changbing; Zhang, Yu; You, Minghong; Yang, Fuyu; Zhang, Jin

    2013-01-01

    Background E. arundinaceus (Retz.) Jeswiet is a warm-season, tall-growing perennial species native to much southern portion in China. The grass has been extensively used in sugarcane breeding and is recently targeted as a bioenergy feedstock crop. However, information on the genetic structure of the Chinese wild germplasm is limited. Knowledge of genetic variation within and among populations is essential for breeding new cultivars in the species. The major objective of this study was to quantify the magnitude of genetic variation among and within natural populations in China. Methodology/Principal Findings In this experiment, we analyzed genetic variation of 164 individuals of 18 populations collected from natural habitats in six Chinese provinces using 20 sequence-related amplified polymorphism (SRAP) primer pairs generating 277 polymorphic bands. Among and within the populations, the percentage of polymorphic bands (PPB) was 80.00% and 27.07%, genetic diversity (HE) was 0.245 and 0.099, effective number of alleles (NE) was 1.350 and 1.170, and Shannon's information index (I) was 0.340 and 0.147, respectively. The populations were clustered into six groups exhibiting a high level of genetic differentiation, which was highly associated with geographic origins of respective germplasm populations, but was not significantly associated with geographic distances between the populations. Conclusions/Significance This is the first report indicating that large genetic variation exists in the Chinese E. arundinaceus germplasm based on the SRAP molecular marker analysis of native populations. The genetic structure of populations in the species has been substantially affected by geographic landforms and environments. The diverse collection will be highly valuable in genetic improvement in the species per se and likely in sugarcane. PMID:24282538

  12. Early and Middle Permian paleoclimates of the Baoshan Block, western Yunnan, China: insight from carbonates

    NASA Astrophysics Data System (ADS)

    Yan, Jiaxin; Liang, Dingyi

    2005-03-01

    In Permian times the Baoshan Block of western Yunnan, southwest China formed the eastern part of the Cimmerian Continent. Most biogeographical and sedimentological data indicate that the Early Permian Dingjiazhai Formation formed on the block under conditions strongly influenced by the Permo-Carboniferous glaciation. After Early Permian rifting, with post-glaciation climatic amelioration, and as the Baoshan Block drifted northwards to approach South China and Indochina, faunal elements characteristic of Gondwana affinity decreased, while those of Cathaysian affinity increased. Finally, Late Permian faunas are characterized by exclusively Cathaysian elements. This shift of marine provinciality becomes an important indicator in understanding the Permian paleoclimatic evolution of the region. This research investigated the composition of carbonate grain associations and the early diagenetic features of limestones from the upper part of the Dingjiazhai Formation, and from the overlying Yongde and Shazipo formations. A sharp distinction in petrological and diagenetic features is recognized between the Dingjiazhai Formation and the two overlying formations. The Dingjiazhai carbonates are characterized by the bryonoderm (bryozoan-echinoderm)-extended facies of the heterozoan association, with no non-skeletal grains. Because early diagenetic cement was rarely formed, the Dingjiazhai carbonates experienced strong diagenetic compaction. In contrast, the Yongde and Shazipo carbonates show a chloroforam facies of photozoan association, with the common occurrence of non-skeletal grains. These carbonates were well cemented during early diagenetic processes. From comparison with Permian cool-water carbonates from northern Pangea and Tasmania, Australia, the Dingjiazhai carbonates are interpreted as deposits of warm-temperate conditions, while the overlying carbonates are considered to be deposits of subtropical or tropical conditions. This climatic interpretation, based on the

  13. Insight into the Earthquake Risk Information Seeking Behavior of the Victims: Evidence from Songyuan, China.

    PubMed

    Li, Shasha; Zhai, Guofang; Zhou, Shutian; Fan, Chenjing; Wu, Yunqing; Ren, Chongqiang

    2017-03-07

    Efficient risk communication is a vital way to reduce the vulnerability of individuals when facing emergency risks, especially regarding earthquakes. Efficient risk communication aims at improving the supply of risk information and fulfilling the need for risk information by individuals. Therefore, an investigation into individual-level information seeking behavior within earthquake risk contexts is very important for improved earthquake risk communication. However, at present there are very few studies that have explored the behavior of individuals seeking earthquake risk information. Under the guidance of the Risk Information Seeking and Processing model as well as relevant practical findings using the structural equation model, this study attempts to explore the main determinants of an individual's earthquake risk information seeking behavior, and to validate the mediator effect of information need during the seeking process. A questionnaire-based survey of 918 valid respondents in Songyuan, China, who had been hit by a small earthquake swarm, was used to provide practical evidence for this study. Results indicated that information need played a noteworthy role in the earthquake risk information seeking process, and was detected both as an immediate predictor and as a mediator. Informational subjective norms drive the seeking behavior on earthquake risk information through both direct and indirect approaches. Perceived information gathering capacity, negative affective responses and risk perception have an indirect effect on earthquake risk information seeking behavior via information need. The implications for theory and practice regarding risk communication are discussed and concluded.

  14. New insight on the opening of the South China Sea basin

    NASA Astrophysics Data System (ADS)

    Hsu, Shu-Kun; Armada, Leo; Doo, Wen-Bin; Yeh, Yi-Ching

    2016-04-01

    The tectonic evolution of the South China Sea (SCS) plays an important role on the geodynamics of Southeast Asia. Recent results from the International Ocean Discovery Program (IODP) Expedition 349 confirmed that the SCS seafloor spreading stopped in the middle Miocene. However, the definite mechanism for the SCS opening is still enigmatic. Using multi-beam bathymetric data, seismic reflection profiles and geomagnetic modeling, we have analyzed the seafloor-spreading pattern and geomagnetic stripes of the SCS. Our results show that an excessive magma supply affecting the SCS occurred at the Early Miocene Climatic Optimum (EMCO). Consequently, four major tectonic events ensued. Firstly, the East Subbasin of the SCS dramatically changed its seafloor spreading direction from north-south to northwest-southeast. Secondly, a northeastward propagating rift occurred in the East Subbasin but stopped in the middle Miocene, just before the cessation of the SCS seafloor spreading. Thirdly, the opening of the SCS extended southwestward and created the Southwest Subbasin. Fourthly, the initiation of the southeastward subduction of the SCS lithosphere occurred and the Manila Trench was formed.

  15. Insight into the Earthquake Risk Information Seeking Behavior of the Victims: Evidence from Songyuan, China

    PubMed Central

    Li, Shasha; Zhai, Guofang; Zhou, Shutian; Fan, Chenjing; Wu, Yunqing; Ren, Chongqiang

    2017-01-01

    Efficient risk communication is a vital way to reduce the vulnerability of individuals when facing emergency risks, especially regarding earthquakes. Efficient risk communication aims at improving the supply of risk information and fulfilling the need for risk information by individuals. Therefore, an investigation into individual-level information seeking behavior within earthquake risk contexts is very important for improved earthquake risk communication. However, at present there are very few studies that have explored the behavior of individuals seeking earthquake risk information. Under the guidance of the Risk Information Seeking and Processing model as well as relevant practical findings using the structural equation model, this study attempts to explore the main determinants of an individual’s earthquake risk information seeking behavior, and to validate the mediator effect of information need during the seeking process. A questionnaire-based survey of 918 valid respondents in Songyuan, China, who had been hit by a small earthquake swarm, was used to provide practical evidence for this study. Results indicated that information need played a noteworthy role in the earthquake risk information seeking process, and was detected both as an immediate predictor and as a mediator. Informational subjective norms drive the seeking behavior on earthquake risk information through both direct and indirect approaches. Perceived information gathering capacity, negative affective responses and risk perception have an indirect effect on earthquake risk information seeking behavior via information need. The implications for theory and practice regarding risk communication are discussed and concluded. PMID:28272359

  16. Short-term effects of social encouragement on exercise behavior: insights from China's Wanbu network.

    PubMed

    Wang, Liuan; Guo, Xitong; Wu, Tianshi; Lv, Lucheng; Zhang, Zhiwei

    2017-07-01

    The objective is to explore the short-term effects of social encouragement on exercise behavior in China. A longitudinal observational study. We collected longitudinal data on exercise and social interactions through public access to the Wanbu network, a large Chinese social network designed to encourage people to walk more. Our data set consisted of 5010 subjects who participated in the network between March 14, 2014, and September 4, 2015, and had at least one social interaction recorded. The data were analyzed using linear regression models relating the number of steps (NS) walked per day to the number of comments (NC), number of thumbs-up (NT), and number of posts (NP) received on the previous day, while adjusting for day of week, quarter of year, and a fixed or random subject effect, with or without a lag term (NS on the previous day) to account for serial correlation. We found that all three social interactions have positive effects on the next day's exercise level. The estimated effect sizes can be ordered as NT > NC > NP for each of the four models considered. The results also indicate that the participants walked less in the first quarter than in the other three quarters and more on weekdays than on weekends, with Monday being the most active day of a week. Social encouragement has positive short-term effects on exercise behavior. Copyright © 2017 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  17. New insights into pulsar wind nebula evolution with H.E.S.S. I and II

    NASA Astrophysics Data System (ADS)

    Klepser, S.; Aharonian, F.; Angüner, E. O.; Casanova, S.; Hahn, J.; Mariaud, C.; Mayer, M.; Mitchell, A.; Oya, I.; Valerius, K.; Zefi, F.

    2017-01-01

    The most numerous TeV sources in the Milky Way are pulsar wind nebulae (PWNe); giant plasma clouds built up from the outflow of pulsars after stellar death. All PWNe observed with the H.E.S.S. I array have been reanalysed in the context of the H.E.S.S. Galactic Plane Survey data release. This allowed for a comprehensive population study to shed light on the evolutionary sequence of PWNe during the first 105 years after the birth of the pulsar. A prototypical example of a middle-aged PWN is the very extended HESS J1825-137. It has been observed with the H.E.S.S. II array, leading to a lower energy threshold and, in combination with previous observations, substantially increased datasets. We can therefore present new spectral studies and unprecedentedly rich images that map out the out flow process of the shocked particle wind. The data also gave rise to a new study of its neighboring source HESS J1826-130, which is one of the hardest spectrum sources in the Galaxy.

  18. The plastoquinol-plastoquinone exchange mechanism in photosystem II: insight from molecular dynamics simulations.

    PubMed

    Zobnina, Veranika; Lambreva, Maya D; Rea, Giuseppina; Campi, Gaetano; Antonacci, Amina; Scognamiglio, Viviana; Giardi, Maria Teresa; Polticelli, Fabio

    2017-01-01

    In the photosystem II (PSII) of oxygenic photosynthetic organisms, the reaction center (RC) core mediates the light-induced electron transfer leading to water splitting and production of reduced plastoquinone molecules. The reduction of plastoquinone to plastoquinol lowers PSII affinity for the latter and leads to its release. However, little is known about the role of protein dynamics in this process. Here, molecular dynamics simulations of the complete PSII complex embedded in a lipid bilayer have been used to investigate the plastoquinol release mechanism. A distinct dynamic behavior of PSII in the presence of plastoquinol is observed which, coupled to changes in charge distribution and electrostatic interactions, causes disruption of the interactions seen in the PSII-plastoquinone complex and leads to the "squeezing out" of plastoquinol from the binding pocket. Displacement of plastoquinol closes the second water channel, recently described in a 2.9 Å resolution PSII structure (Guskov et al. in Nat Struct Mol Biol 16:334-342, 2009), allowing to rule out the proposed "alternating" mechanism of plastoquinol-plastoquinone exchange, while giving support to the "single-channel" one. The performed simulations indicated a pivotal role of D1-Ser264 in modulating the dynamics of the plastoquinone binding pocket and plastoquinol-plastoquinone exchange via its interaction with D1-His252 residue. The effects of the disruption of this hydrogen bond network on the PSII redox reactions were experimentally assessed in the D1 site-directed mutant Ser264Lys.

  19. Insight into glucosidase II from the red marine microalga Porphyridium sp. (Rhodophyta).

    PubMed

    Levy-Ontman, Oshrat; Fisher, Merav; Shotland, Yoram; Tekoah, Yoram; Malis Arad, Shoshana

    2015-12-01

    N-glycosylation of proteins is one of the most important post-translational modifications that occur in various organisms, and is of utmost importance for protein function, stability, secretion, and loca-lization. Although the N-linked glycosylation pathway of proteins has been extensively characterized in mammals and plants, not much information is available regarding the N-glycosylation pathway in algae. We studied the α 1,3-glucosidase glucosidase II (GANAB) glycoenzyme in a red marine microalga Porphyridium sp. (Rhodophyta) using bioinformatic and biochemical approaches. The GANAB-gene was found to be highly conserved evolutionarily (compo-sed of all the common features of α and β subunits) and to exhibit similar motifs consistent with that of homolog eukaryotes GANAB genes. Phylogenetic analysis revealed its wide distribution across an evolutionarily vast range of organisms; while the α subunit is highly conserved and its phylogenic tree is similar to the taxon evolutionary tree, the β subunit is less conserved and its pattern somewhat differs from the taxon tree. In addition, the activity of the red microalgal GANAB enzyme was studied, including functional and biochemical characterization using a bioassay, indicating that the enzyme is similar to other eukaryotes ortholog GANAB enzymes. A correlation between polysaccharide production and GANAB activity, indicating its involvement in polysaccharide biosynthesis, is also demonstrated. This study represents a valuable contribution toward understanding the N-glycosylation and polysaccharide biosynthesis pathways in red microalgae.

  20. New Insights To Simulate the Luminescence Properties of Pt(II) Complexes Using Quantum Calculations.

    PubMed

    Massuyeau, Florian; Faulques, Eric; Latouche, Camille

    2017-03-24

    The present manuscript reports a thorough quantum investigation on the luminescence properties of three monoplatinum(II) complexes. First, the simulated bond lengths at the ground state are compared to the observed ones, and the simulated electronic transitions are compared to the reported ones in the literature in order to assess our methodology. In a second time we show that geometries from the first triplet excited state are similar to the ground state ones. Simulations of the phosphorescence spectra from the first triplet excited states have been performed taking into account the vibronic coupling effects together with mode-mixing (Dushinsky) and solvent effects. Our simulations are compared with the observed ones already reported in the literature and are in good agreement. The calculations demonstrate that the normal modes of low energy are of great importance on the phosphorescence signature. When temperature effects are taken into account, the simulated phosphorescence spectra are drastically improved. An analysis of the computational time shows that the vibronic coupling simulation is cost-effective and thus can be extended to treat large transition metal complexes. In addition to the intrinsic importance of the investigated targets, this work provides a robust method to simulate phosphorescence spectra and to increase the duality experiment-theory.

  1. Atmospheric mercury in the Canadian Arctic. Part II: insight from modeling.

    PubMed

    Dastoor, Ashu; Ryzhkov, Andrew; Durnford, Dorothy; Lehnherr, Igor; Steffen, Alexandra; Morrison, Heather

    2015-03-15

    A review of mercury in the Canadian Arctic with a focus on field measurements is presented in part I (see Steffen et al., this issue). Here we provide insights into the dynamics of mercury in the Canadian Arctic from new and published mercury modeling studies using Environment Canada's mercury model. The model simulations presented in this study use global anthropogenic emissions of mercury for the period 1995-2005. The most recent modeling estimate of the net gain of mercury from the atmosphere to the Arctic Ocean is 75 Mg year(-1) and the net gain to the terrestrial ecosystems north of 66.5° is 42 Mg year(-1). Model based annual export of riverine mercury from North American, Russian and all Arctic watersheds to the Arctic Ocean are in the range of 2.8-5.6, 12.7-25.4 and 15.5-31.0 Mg year(-1), respectively. Analysis of long-range transport events of Hg at Alert and Little Fox Lake monitoring sites indicates that Asia contributes the most ambient Hg to the Canadian Arctic followed by contributions from North America, Russia, and Europe. The largest anthropogenic Hg deposition to the Canadian Arctic is from East Asia followed by Europe (and Russia), North America, and South Asia. An examination of temporal trends of Hg using the model suggests that changes in meteorology and changes in anthropogenic emissions equally contribute to the decrease in surface air elemental mercury concentrations in the Canadian Arctic with an overall decline of ~12% from 1990 to 2005. A slow increase in net deposition of Hg is found in the Canadian Arctic in response to changes in meteorology. Changes in snowpack and sea-ice characteristics and increase in precipitation in the Arctic related with climate change are found to be primary causes for the meteorology-related changes in air concentrations and deposition of Hg in the region. The model estimates that under the emissions reduction scenario of worldwide implementation of the best emission control technologies by 2020, mercury

  2. The characteristics of dissolved organic matter (DOM) in storm sewer sediments and the binding interaction with Cu(II) in four typical regions in Beijing, China.

    PubMed

    Zhang, Ziyang; Li, Kun; Zhang, Xiaoran; Li, Haiyan

    2017-07-01

    In this work, dissolved organic matter (DOM) was extracted from storm sewer sediments collected in four typical regions (residential, campus, traffic and business regions) in Beijing, China. The basic characteristics of DOM were analyzed by UV-visible spectroscopy (UV-Vis), excitation-emission matrix Fluorescence Spectroscopy and Fourier Transform Infrared Spectroscopy. Furthermore, the complexation between DOM and Cu(II) were investigated. The results showed that there were large amount of aromatic structure in the DOM extracted from storm sewer sediments. The microbial activities had also made a contribution to the DOM in storm sewer sediments. The composition of DOM influenced the complexing capacity of Cu(II) greatly, which may be attributed to the protein-like and humic-like substances in storm sewer sediments. This study demonstrated valuable information on the structure present in the DOM of storm sewer sediments and provided new insight for exploring the relationship between DOM and co-existing heavy metals in storm sewer sediments.

  3. Mechanistic insight into the reaction catalysed by bacterial type II dehydroquinases.

    PubMed

    Coderch, Claire; Lence, Emilio; Peón, Antonio; Lamb, Heather; Hawkins, Alastair R; Gago, Federico; González-Bello, Concepción

    2014-03-15

    DHQ2 (type II dehydroquinase), which is an essential enzyme in Helicobacter pylori and Mycobacterium tuberculosis and does not have any counterpart in humans, is recognized to be an attractive target for the development of new antibacterial agents. Computational and biochemical studies that help understand in atomic detail the catalytic mechanism of these bacterial enzymes are reported in the present paper. A previously unknown key role of certain conserved residues of these enzymes, as well as the structural changes responsible for triggering the release of the product from the active site, were identified. Asp89*/Asp88* from a neighbouring enzyme subunit proved to be the residue responsible for the deprotonation of the essential tyrosine to afford the catalytic tyrosinate, which triggers the enzymatic process. The essentiality of this residue is supported by results from site-directed mutagenesis. For H. pylori DHQ2, this reaction takes place through the assistance of a water molecule, whereas for M. tuberculosis DHQ2, the tyrosine is directly deprotonated by the aspartate residue. The participation of a water molecule in this deprotonation reaction is supported by solvent isotope effects and proton inventory studies. MD simulation studies provide details of the required motions for the catalytic turnover, which provides a complete overview of the catalytic cycle. The product is expelled from the active site by the essential arginine residue and after a large conformational change of a loop containing two conserved arginine residues (Arg109/Arg108 and Arg113/Arg112), which reveals a previously unknown key role for these residues. The present study highlights the key role of the aspartate residue whose blockage could be useful in the rational design of inhibitors and the mechanistic differences between both enzymes.

  4. Structural insight into the evolutionary and pharmacologic homology of glutamate carboxypeptidases II and III

    SciTech Connect

    Hlouchova, Klara; Barinka, Cyril; Konvalinka, Jan; Lubkowski, Jacek

    2009-10-23

    Glutamate carboxypeptidase III (GCPIII) is a metalloenzyme that belongs to the transferrin receptor/glutamate carboxypeptidase II (GCPII; EC 3.4.17.21) superfamily. GCPIII has been studied mainly because of its evolutionary relationship to GCPII, an enzyme involved in a variety of neuropathologies and malignancies, such as glutamatergic neurotoxicity and prostate cancer. Given the potential functional and pharmacological overlap between GCPIII and GCPII, studies addressing the structural and physiological properties of GCPIII are crucial for obtaining a deeper understanding of the GCPII/GCPIII system. In the present study, we report high-resolution crystal structures of the human GCPIII ectodomain in a 'pseudo-unliganded' state and in a complex with: (a) L-glutamate (a product of hydrolysis); (b) a phosphapeptide transition state mimetic, namely (2S,3'S)-{l_brace}[(3'-amino-3'-carboxy-propyl)-hydroxyphosphinoyl]methyl{r_brace}-pentanedioic acid; and (c) quisqualic acid, a glutamate biostere. Our data reveal the overall fold and quaternary arrangement of the GCPIII molecule, define the architecture of the GCPIII substrate-binding cavity, and offer an experimental evidence for the presence of Zn{sup 2+} ions in the bimetallic active site. Furthermore, the structures allow us to detail interactions between the enzyme and its ligands and to characterize the functional flexibility of GCPIII, which is essential for substrate recognition. A comparison of these GCPIII structures with the equivalent GCPII complexes reveals differences in the organization of specificity pockets, in surface charge distribution, and in the occupancy of the co-catalytic zinc sites. The data presented here provide information that should prove to be essential for the structurally-aided design of GCPIII-specific inhibitors and might comprise guidelines for future comparative GCPII/GCPIII studies.

  5. New insights into the mineralogy of the Atlantis II Deep metalliferous sediments, Red Sea

    NASA Astrophysics Data System (ADS)

    Laurila, Tea E.; Hannington, Mark D.; Leybourne, Matthew; Petersen, Sven; Devey, Colin W.; Garbe-Schönberg, Dieter

    2015-12-01

    The Atlantis II Deep of the Red Sea hosts the largest known hydrothermal ore deposit on the ocean floor and the only modern analog of brine pool-type metal deposition. The deposit consists mainly of chemical-clastic sediments with input from basin-scale hydrothermal and detrital sources. A characteristic feature is the millimeter-scale layering of the sediments, which bears a strong resemblance to banded iron formation (BIF). Quantitative assessment of the mineralogy based on relogging of archived cores, detailed petrography, and sequential leaching experiments shows that Fe-(oxy)hydroxides, hydrothermal carbonates, sulfides, and authigenic clays are the main "ore" minerals. Mn-oxides were mainly deposited when the brine pool was more oxidized than it is today, but detailed logging shows that Fe-deposition and Mn-deposition also alternated at the scale of individual laminae, reflecting short-term fluctuations in the Lower Brine. Previous studies underestimated the importance of nonsulfide metal-bearing components, which formed by metal adsorption onto poorly crystalline Si-Fe-OOH particles. During diagenesis, the crystallinity of all phases increased, and the fine layering of the sediment was enhanced. Within a few meters of burial (corresponding to a few thousand years of deposition), biogenic (Ca)-carbonate was dissolved, manganosiderite formed, and metals originally in poorly crystalline phases or in pore water were incorporated into diagenetic sulfides, clays, and Fe-oxides. Permeable layers with abundant radiolarian tests were the focus for late-stage hydrothermal alteration and replacement, including deposition of amorphous silica and enrichment in elements such as Ba and Au.

  6. Precambrian tectonic evolution of the Tarim Block, NW China: New geochronological insights from the Quruqtagh domain

    NASA Astrophysics Data System (ADS)

    Shu, L. S.; Deng, X. L.; Zhu, W. B.; Ma, D. S.; Xiao, W. J.

    2011-10-01

    break-up of Rodinia supercontinent. The geological indicators of break-up such as Neoproterozoic granite, bimodal igneous rocks, composite magmatic flow, basic dyke swarm and continental rift type basins are well developed, followed by a large-scale of late Neoproterozoic glacier event. Four stages of magmatism mentioned above constitute major events in the Precambrian evolution of Tarim and Central Asian. These data, combining with previous U-Pb ages from igneous rocks, provide a significant line of evidence for understanding the Rodinia evolution of Tarim and the relationships with South China, east India and east Antarctica, Lesser and Great Himalaya blocks in Proterozoic. A primary reconstruction of the Tarim Block, connecting it with South China, east India and east Antarctica, Lesser and Great Himalaya blocks, is finally proposed.

  7. Initial insights into the age and origin of the Kubuqi sand sea of northern China

    NASA Astrophysics Data System (ADS)

    Yang, Xiaoping; Forman, Steven; Hu, Fangen; Zhang, Deguo; Liu, Ziting; Li, Hongwei

    2016-04-01

    The Kubuqi Desert is the only active sand sea in the semiarid regions of northern China and occurs along the southern margin of the Yellow River. Little is known about the age and origin of this large (17,000 km2) sand sea with a present annual precipitation of 200-480 mm. Sand drift potentials indicated net capable winds for aeolian transport are from the northwest, though winds are stronger to north beyond the dune field than within the sand sea. Geomorphic and stratigraphic observations indicate that Holocene aeolian sand often drapes over bedrock and river terraces as a palimpsest landscape. Field investigations identified four stratigraphic sections with multiple aeolian sand units and palaeosols, with age control by optically stimulated luminescence (OSL) dating of quartz grains. Palaeosols are weakly developed, mostly accumulative A horizon with organic carbon content < 1% and reflect sand sheet deposition possibly in a steppe environment. Although sediments near river channels or former lakes might give old ages, the initial formation and age of the Kubuqi sand sea should be judged from the occurrence of the sandy palimpsest of the landscape that is OSL dated to the Holocene in general. The latest period of aeolian reactivation may be related to human activity associated with grazing and farming from lost cities in the Kubuqi Desert during the Han (206 B.C. - A.D. 220) and the Tang (A.D. 608 - 907) Dynasties. Also, variable discharge of the Yellow River with local diversions for irrigation and throughout the catchment resulted in possibly an increased supply of aeolian particles for dune field expansion in the past 2 ka.

  8. Origin of water in the Badain Jaran Desert, China: new insight from isotopes

    NASA Astrophysics Data System (ADS)

    Wu, Xiujie; Wang, Xu-Sheng; Wang, Yang; Hu, Bill X.

    2017-09-01

    To better understand the origin of water in the Badain Jaran Desert, China, water samples were collected from lakes, a spring and local unconfined aquifer for analyses of radiocarbon (14C), tritium (3H), stable hydrogen and oxygen isotope ratios (δ2H - δ18O), and d-excess values ( = δ2H - 8δ18O). A series of evaporation experiments were also conducted in the desert to examine how the isotopic signature of water may change during evaporation and infiltration under local environmental conditions. The results show that the lakes in the southeastern sand dune area are fed by groundwater discharging into the lakes and that local groundwater, on the other hand, is derived primarily from modern meteoric precipitation in the region. Although dissolved inorganic carbon (DIC) in groundwater yielded very old radiocarbon ages, the presence of detectable amounts of tritium in groundwater samples, together with their δ2H, δ18O and d-excess characteristics, strongly suggests that the old radiocarbon ages of DIC do not represent the residence time of water in the aquifer but are the result of addition of old DIC derived from dissolution of ancient carbonates in the aquifer. The data do not support the hypothesis that the water in the Badain Jaran Desert was sourced in remote mountains on the northern Tibetan Plateau. This study also finds no support for the hypothesis that present-day water resources in the desert were recharged by the precipitation that fell in the past during the early Holocene when the climate was much wetter than today. Instead, this study shows that both groundwater and lake water originated from meteoric precipitation in the region including mountainous areas adjacent to the desert under the modern climatic condition.

  9. Polybrominated diphenyl ethers in birds from Chongming Island, Yangtze estuary, China: insight into migratory behavior.

    PubMed

    Huang, Kai; Lin, Kuangfei; Guo, Jie; Zhou, Xiaoyu; Wang, Junxia; Zhao, Jianhua; Zhou, Peng; Xu, Feng; Liu, Lili; Zhang, Wei

    2013-06-01

    Sum-PBDEs concentrations in shorebirds and Anatidae ducks muscles from Chongming Dongtan National Nature Reserve ranged from 21-324 to 14-159ngg(-1) lw, respectively. PBDEs were detected in muscles of all the studied species. Compared with flyways around the world, migratory waterbirds on the East Asian-Australasian flyway exhibited lower PBDEs burdens than those reported on Black Sea-Mediterranean flyway in Europe and Pacific, Atlantic, Mississippi flyway in North America. Residential Eurasian tree sparrow samples indicated few PBDE products were used in Chongming Island developed in the idea of world famous eco-island. There was no significant difference in PBDEs concentrations between shorebirds and ducks. However, PBDEs composition varied between them. BDE 209 (29-44%) contributed to sum-PBDEs more than BDE 47 (17-19%) in muscles of ducks, while BDE 47 was the predominant congener in shorebirds contributing 32-48%. Stable nitrogen and carbon isotopes and stomach content analysis indicated shorebirds and ducks had the same dietary composition, but showed different preference to bivalves, gastropods and crustaceans for shorebirds and aquatic plant material for ducks. Migratory species had inherent migratory routes and thus had exposure to PBDEs during their stay in breeding grounds, stopover sites and wintering grounds with high use of different commercial PBDE mixtures. Higher percentage of BDE 209 in ducks than shorebirds suggested that breeding ranges and wintering grounds of ducks comprise wetlands in inland and coastal China and Korea where decaBDEs pollution was serious in Asian-Pacific region. Our findings reveal the influence of migratory behavior on PBDEs distribution in migratory waterbirds.

  10. Factors affecting farmers' behaviour in pesticide use: Insights from a field study in northern China.

    PubMed

    Fan, Liangxin; Niu, Haipeng; Yang, Xiaomei; Qin, Wei; Bento, Célia P M; Ritsema, Coen J; Geissen, Violette

    2015-12-15

    Quantitative understanding of farmers' behaviour in pesticide use is critical to enhance sustainability of chemical pest control and protect farmers' health and the environment. However, reports on the levels of knowledge and awareness of farmers and the practices of pesticide use are often insufficient. Here, we conducted a comprehensive analysis on the effects of knowledge and awareness of farmers as well as the influence of the associated stakeholders (i.e. pesticide retailers and the government) on farmers' behaviour in pesticide use by using a detailed survey of 307 agricultural households (79 grain farms, 65 fruit farms, 53 vegetable farms and 110 mixed-crop farms) in the Wei River basin in northern China. Eight protective behaviours (PBs) were exhibited by farmers. Careful and safe storage of pesticides, changing clothes or showering after applying pesticides, and reading instructions of the container labels before application were the most frequent PBs. Vegetable and fruit farmers had higher levels of education and knowledge than grain farmers, but the former were less willing to reduce pesticide use because of fear of low profits and lack of trust in the government and pesticide retailers. The PBs of farmers were strongly affected by the perception of the consequences of their behaviour (standardised path coefficient, SPC=0.42) and the level of farmers' knowledge (SPC=0.33). Pesticide retailers and the government had a moderate and weak influence, respectively, on farmers' PBs, suggesting a large gap of trust among farmers, pesticide retailers, and the government. Training and supervising retailers, educating farmers, and improving information transparency across farmers, pesticide retailers and the staff of the Agricultural Extension and Technology Service are recommended for bridging the gap of trust between farmers and the associated stakeholders as well as for promoting the use of PBs among farmers. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Source apportionment of carbonaceous aerosols in a megacity of northwest China: insights from radiocarbon measurement

    NASA Astrophysics Data System (ADS)

    Ni, Haiyan; Huang, Rujin; Dusek, Ulrike

    2017-04-01

    Fine particulate matter (PM2.5) samples were collected from 5 July 2008 to 27 June 2009 at Xi'an, a very polluted megacity in Northwest China. The 24 h averaged PM2.5concentrations (ranged from 32 μg m-3 to 339 μg m-3) were 1-14 times higher than the WHO guideline for 24 h PM2.5(25 μg m-3). In this work, we unambiguously quantify fossil (e.g., vehicle emissions, coal burning etc.) and non-fossil (e.g., biomass burning, cooking, biogenic emissions etc.) contributions to organic carbon (OC) and elemental carbon (EC) of PM2.5using radiocarbon (14C) measurement. In addition, we measured PM2.5 major components and source markers, including OC and EC, ions, trace elements, polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs (o-PAHs), anhydrous sugars and hopanes. The preliminary results of radiocarbon measurements in OC and EC show that the annual mean contributions from fossil-fuel combustion to EC was 76 ± 8% (6 ± 2 μg m-3). The remaining 24 ± 8% (2 ± 1 μg m-3) was attributed to biomass burning, with higher contribution in the cold period (˜33%) compared to the warm period (˜21%), due to enhanced emissions from local biomass burning activities in winter. In contrast with EC, OC was dominated by non-fossil sources, with an annual average of 54 ± 8 % (13 ± 10 μg m-3). Clear seasonal variations were seen in OC concentrations both from fossil fuel (OCff), and from non-fossil sources (OCnf), with maxima in the cold period and minima in the warm period, because of enhanced fossil and non-fossil activities in winter, mainly biomass burning and domestic coal burning. Further source apportionment of OC, including primary/secondary fossil OC, primary/secondary non-fossil OC, will be conducted by combining 14C results with positive matrix factorization (PMF) analysis of organic matter (OM).

  12. Insights from computational analysis of full-length β-ketoacyl-[ACP] synthase-II cDNA isolated from American and African oil palms.

    PubMed

    Bhore, Subhash J; Cha, Thye S; Amelia, Kassim; Shah, Farida H

    2014-01-01

    Palm oil derived from fruits (mesocarp) of African oil palm (Elaeis guineensis Jacq. Tenera) and American oil palm (E. oleifera) is important for food industry. Due to high yield, Elaeis guineensis (Tenera) is cultivated on commercial scale, though its oil contains high (~54%) level of saturated fatty acids. The rate-limiting activity of beta-ketoacyl-[ACP] synthase-II (KAS-II) is considered mainly responsible for the high (44%) level of palmitic acid (C16:0) in the oil obtained from E. guineensis. The objective of this study was to annotate KAS-II cDNA isolated from American and African oil palms. The full-length E. oleifera KAS-II (EoKAS-II) cDNA clone was isolated using random method of gene isolation. Whereas, the E. guineensis KAS-II (EgTKAS-II) cDNA was isolated using reverse transcriptase polymerase chain reaction (RT-PCR) technique; and missing ends were obtained by employing 5'and 3' RACE technique. The results show that EoKAS-II and EgTKAS-II open reading frames (ORFs) are of 1689 and 1721 bp in length, respectively. Further analysis of the both EoKAS-II and EgTKAS-II predicted protein illustrates that they contains conserved domains for 'KAS-I and II', 'elongating' condensing enzymes, 'condensing enzymes super-family', and '3-oxoacyl-[ACP] synthase II'. The predicted protein sequences shows 95% similarity with each other. Consecutively, the three active sites (Cys, His, and His) were identified in both proteins. However, difference in positions of two active Histidine (His) residues was noticed. These insights may serve as the foundation in understanding the variable activity of KAS-II in American and African oil palms; and cDNA clones could be useful in the genetic engineering of oil palms.

  13. Study on transient beam loading compensation for China ADS proton linac injector II

    NASA Astrophysics Data System (ADS)

    Gao, Zheng; He, Yuan; Wang, Xian-Wu; Chang, Wei; Zhang, Rui-Feng; Zhu, Zheng-Long; Zhang, Sheng-Hu; Chen, Qi; Powers, Tom

    2016-05-01

    Significant transient beam loading effects were observed during beam commissioning tests of prototype II of the injector for the accelerator driven sub-critical (ADS) system, which took place at the Institute of Modern Physics, Chinese Academy of Sciences, between October and December 2014. During these tests experiments were performed with continuous wave (CW) operation of the cavities with pulsed beam current, and the system was configured to make use of a prototype digital low level radio frequency (LLRF) controller. The system was originally operated in pulsed mode with a simple proportional plus integral and deviation (PID) feedback control algorithm, which was not able to maintain the desired gradient regulation during pulsed 10 mA beam operations. A unique simple transient beam loading compensation method which made use of a combination of proportional and integral (PI) feedback and feedforward control algorithm was implemented in order to significantly reduce the beam induced transient effect in the cavity gradients. The superconducting cavity field variation was reduced to less than 1.7% after turning on this control algorithm. The design and experimental results of this system are presented in this paper. Supported by National Natural Science Foundation of China (91426303, 11525523)

  14. Structure of tagatose-1,6-bisphosphate aldolase. Insight into chiral discrimination, mechanism, and specificity of class II aldolases.

    PubMed

    Hall, David R; Bond, Charles S; Leonard, Gordon A; Watt, C Ian; Berry, Alan; Hunter, William N

    2002-06-14

    Tagatose-1,6-bisphosphate aldolase (TBPA) is a tetrameric class II aldolase that catalyzes the reversible condensation of dihydroxyacetone phosphate with glyceraldehyde 3-phosphate to produce tagatose 1,6-bisphosphate. The high resolution (1.45 A) crystal structure of the Escherichia coli enzyme, encoded by the agaY gene, complexed with phosphoglycolohydroxamate (PGH) has been determined. Two subunits comprise the asymmetric unit, and a crystallographic 2-fold axis generates the functional tetramer. A complex network of hydrogen bonds position side chains in the active site that is occupied by two cations. An unusual Na+ binding site is created using a pi interaction with Tyr183 in addition to five oxygen ligands. The catalytic Zn2+ is five-coordinate using three histidine nitrogens and two PGH oxygens. Comparisons of TBPA with the related fructose-1,6-bisphosphate aldolase (FBPA) identifies common features with implications for the mechanism. Because the major product of the condensation catalyzed by the enzymes differs in the chirality at a single position, models of FBPA and TBPA with their cognate bisphosphate products provide insight into chiral discrimination by these aldolases. The TBPA active site is more open on one side than FBPA, and this contributes to a less specific enzyme. The availability of more space and a wider range of aldehyde partners used by TBPA together with the highly specific nature of FBPA suggest that TBPA might be a preferred enzyme to modify for use in biotransformation chemistry.

  15. Osteoarthritis, labour division, and occupational specialization of the Late Shang China - insights from Yinxu (ca. 1250 - 1046 B.C.).

    PubMed

    Zhang, Hua; Merrett, Deborah C; Jing, Zhichun; Tang, Jigen; He, Yuling; Yue, Hongbin; Yue, Zhanwei; Yang, Dongya Y

    2017-01-01

    This research investigates the prevalence of human osteoarthritis at Yinxu, the last capital of the Late Shang dynasty (ca. 1250-1046 B.C.), to gain insights about lifeways of early urban populations in ancient China. A total of 167 skeletal remains from two sites (Xiaomintun and Xin'anzhuang) were analyzed to examine osteoarthritis at eight appendicular joints and through three spinal osseous indicators. High osteoarthritis frequencies were found in the remains with males showing significantly higher osteoarthritis on the upper body (compared to that of the females). This distinctive pattern becomes more obvious for males from Xiaomintun. Furthermore, Xiaomintun people showed significantly higher osteoarthritis in both sexes than those from Xin'anzhuang. Higher upper body osteoarthritis is speculated to be caused by repetitive lifting and carrying heavy-weight objects, disproportionately adding more stress and thus more osseous changes to the upper than the lower body. Such lifting-carrying could be derived from intensified physical activities in general and specialized occupations in particular. Higher osteoarthritis in males may reveal a gendered division of labour, with higher osteoarthritis in Xiaomintun strongly indicating an occupational difference between the two sites. The latter speculation can be supported by the recovery of substantially more bronze-casting artifacts in Xiaomintun. It is also intriguing that relatively higher osteoarthritis was noticed in Xiaomintun females, which seems to suggest that those women might have also participated in bronze-casting activities as a "family business." Such a family-involved occupation, if it existed, may have contributed to establishment of occupation-oriented neighborhoods as proposed by many Shang archaeologists.

  16. Osteoarthritis, labour division, and occupational specialization of the Late Shang China - insights from Yinxu (ca. 1250 - 1046 B.C.)

    PubMed Central

    Merrett, Deborah C.; Jing, Zhichun; Tang, Jigen; He, Yuling; Yue, Hongbin; Yue, Zhanwei; Yang, Dongya Y.

    2017-01-01

    This research investigates the prevalence of human osteoarthritis at Yinxu, the last capital of the Late Shang dynasty (ca. 1250–1046 B.C.), to gain insights about lifeways of early urban populations in ancient China. A total of 167 skeletal remains from two sites (Xiaomintun and Xin’anzhuang) were analyzed to examine osteoarthritis at eight appendicular joints and through three spinal osseous indicators. High osteoarthritis frequencies were found in the remains with males showing significantly higher osteoarthritis on the upper body (compared to that of the females). This distinctive pattern becomes more obvious for males from Xiaomintun. Furthermore, Xiaomintun people showed significantly higher osteoarthritis in both sexes than those from Xin’anzhuang. Higher upper body osteoarthritis is speculated to be caused by repetitive lifting and carrying heavy-weight objects, disproportionately adding more stress and thus more osseous changes to the upper than the lower body. Such lifting-carrying could be derived from intensified physical activities in general and specialized occupations in particular. Higher osteoarthritis in males may reveal a gendered division of labour, with higher osteoarthritis in Xiaomintun strongly indicating an occupational difference between the two sites. The latter speculation can be supported by the recovery of substantially more bronze-casting artifacts in Xiaomintun. It is also intriguing that relatively higher osteoarthritis was noticed in Xiaomintun females, which seems to suggest that those women might have also participated in bronze-casting activities as a “family business.” Such a family-involved occupation, if it existed, may have contributed to establishment of occupation-oriented neighborhoods as proposed by many Shang archaeologists. PMID:28464007

  17. Insights from computational analysis of full-length β-ketoacyl-[ACP] synthase-II cDNA isolated from American and African oil palms

    PubMed Central

    Bhore, Subhash J.; Cha, Thye S.; Amelia, Kassim; Shah, Farida H.

    2014-01-01

    Background: Palm oil derived from fruits (mesocarp) of African oil palm (Elaeis guineensis Jacq. Tenera) and American oil palm (E. oleifera) is important for food industry. Due to high yield, Elaeis guineensis (Tenera) is cultivated on commercial scale, though its oil contains high (~54%) level of saturated fatty acids. The rate-limiting activity of beta-ketoacyl-[ACP] synthase-II (KAS-II) is considered mainly responsible for the high (44%) level of palmitic acid (C16:0) in the oil obtained from E. guineensis. Objective: The objective of this study was to annotate KAS-II cDNA isolated from American and African oil palms. Materials and Methods: The full-length E. oleifera KAS-II (EoKAS-II) cDNA clone was isolated using random method of gene isolation. Whereas, the E. guineensis KAS-II (EgTKAS-II) cDNA was isolated using reverse transcriptase polymerase chain reaction (RT-PCR) technique; and missing ends were obtained by employing 5’and 3’ RACE technique. Results: The results show that EoKAS-II and EgTKAS-II open reading frames (ORFs) are of 1689 and 1721 bp in length, respectively. Further analysis of the both EoKAS-II and EgTKAS-II predicted protein illustrates that they contains conserved domains for ‘KAS-I and II’, ‘elongating’ condensing enzymes, ‘condensing enzymes super-family’, and ‘3-oxoacyl-[ACP] synthase II’. The predicted protein sequences shows 95% similarity with each other. Consecutively, the three active sites (Cys, His, and His) were identified in both proteins. However, difference in positions of two active Histidine (His) residues was noticed. Conclusion: These insights may serve as the foundation in understanding the variable activity of KAS-II in American and African oil palms; and cDNA clones could be useful in the genetic engineering of oil palms. PMID:24678202

  18. An insight into the magnetoelectric coupling effect in the MOF of [NH2(CH3)2]n[FeIIIFeII(HCOO)6]n

    NASA Astrophysics Data System (ADS)

    Guo, Jiangbin; Chen, Lihong; Li, Dong; Zhao, Haixia; Dong, Xinwei; Long, Lasheng; Huang, Rongbin; Zheng, Lansun

    2017-05-01

    Understanding the microscopic mechanism of magnetoelectric coupling is of fundamental importance for the rational design of multiferroics. Herein, the magnetoelectric coupling effect in the metal-organic frameworks of [NH2(CH3)2]n[FeIIIFeII(HCOO)6]n (1) was investigated, respectively, through measuring the dielectric properties and ferroelectric polarization of single-crystal 1 along different crystal axes under external magnetic fields. Analysis on the magnetic structure of 1 reveals that the defect in the FeII-FeIII sublattices plays a key contribution to the magnetoelectric coupling of 1, providing a unique insight into the magnetoelectric coupling effect of MOFs-based multiferroics.

  19. Emergence of dengue virus 4 genotype II in Guangzhou, China, 2010: survey and molecular epidemiology of one community outbreak.

    PubMed

    Jing, Qin-Long; Yang, Zhi-Cong; Luo, Lei; Xiao, Xin-Cai; Di, Biao; He, Peng; Fu, Chuan-Xi; Wang, Ming; Lu, Jia-Hai

    2012-04-12

    The re-emergence of dengue virus 4 (DENV-4) has become a public health concern in South America, Southeast Asia and South Asia. However, it has not been known to have caused a local outbreak in China for the past 20 years. The purpose of this study was to elucidate the epidemiology of one local community outbreak caused by DENV-4 in Guangzhou city, China, in 2010; and to determine the molecular characteristics of the genotype II virus involved. During September and October of 2010, one imported case, a Guangzhou resident who travelled back from Thailand, resulted in 18 secondary autochthonous cases in Guangzhou City, with an incidence rate of 5.53 per 10,000 residents. In indigenous cases, 14 serum samples tested positive for IgM against DENV and 7 for IgG from a total of 15 submitted serum samples, accompanied by 5 DENV-4 isolates. With identical envelope gene nucleotide sequences, the two isolates (D10168-GZ from the imported index case and Guangzhou 10660 from the first isolate in the autochthonous cases) were grouped into DENV-4 genotype II after comparison to 32 previous DENV-4 isolates from GenBank that originated from different areas. Based on epidemiological and phylogenetic analyses, the outbreak, which was absent for 20 years after the DENV-4 genotype I outbreak in 1990, was confirmed as DENV-4 genotype II and initially traced to the imported index case, a Guangzhou resident who travelled back from Thailand.

  20. Adsorption kinetics, thermodynamics and isotherm of Hg(II) from aqueous solutions using buckwheat hulls from Jiaodong of China.

    PubMed

    Wang, Zengdi; Yin, Ping; Qu, Rongjun; Chen, Hou; Wang, Chunhua; Ren, Shuhua

    2013-02-15

    The adsorption kinetics and adsorption isotherms of buckwheat hulls in the region of Jiaodong, China (BHJC) for Hg(II) were investigated. Results revealed that the adsorption kinetics of BHJC for Hg(II) were well described by a pseudo second-order reaction model, and the adsorption thermodynamic parameters ΔG, ΔH and ΔS were -5.83 kJ mol(-1)(35°C), 73.1, and 256 JK(-1) mol(-1), respectively. Moreover, Langmuir, Freundlich and Redlich-Peterson isotherm models were applied to analyse the experimental data and to predict the relevant isotherm parameters. The best interpretation for the experimental data was given by the Langmuir isotherm equation, and the maximum adsorption capacity for Hg(II) is 243.90 mg/g at 35°C. Furthermore, investigation of the adsorption selectivity showed that BHJC displayed strong affinity for mercury in the aqueous solutions and exhibited 100% selectivity for mercury in the presence of Zn(II) and Cd(II).

  1. Biogeographical variation and population genetic structure of sporisorium scitamineum in mainland China: Insights from ISSR and SP-SRAP markers

    USDA-ARS?s Scientific Manuscript database

    Sugarcane smut caused by Sporisorium scitamineum is the most important fungal disease in sugarcane growing in Mainland China. A total of 100 pathogen isolates collected from 20 sugarcane growing districts of 7 provinces of China and from 38 sugarcane cultivars, were investigated by inter simple sequ...

  2. China.

    ERIC Educational Resources Information Center

    Semaan, Leslie

    China has the longest continuous civilization in the world--about 4000 years. Another reason to study China is its sheer size in both area and population. This text gives students the opportunity to explore those aspects of Chinese life which have changed in recent years. The extensive history and religion sections allow these changes to be seen…

  3. Structure and spectroscopic investigations of a bi-dentate N‧-[(4-ethylphenyl)methylidene]-4-hydroxybenzohydrazide and its Co(II), Ni(II), Cu(II) and Cd(II) complexes: Insights relevant to biological properties

    NASA Astrophysics Data System (ADS)

    Gopal Reddy, N. B.; Krishna, P. Murali; Shantha Kumar, S. S.; Patil, Yogesh P.; Nethaji, Munirathinam

    2017-06-01

    The present paper describes the synthesis of novel ligand, N‧-[(4-ethylphenyl)methylidene]-4-hydroxy benzohydrazide (HL) and its Co(II), Ni(II), Cu(II) and Cd(II) complexes. The ligand (HL) crystallizes in orthorhombic lattice in P212121 space group with a = 7.9941 (7) Å, b = 11.6154 (10) Å, c = 15.2278 (13) Å, α = β = γ = 90°. Spectroscopic data gives the strong evidence that ligand is coordinated through azomethine nitrogen and enolic oxygen with metal ion. The DNA binding studies revealed that the complexes bind to CT-DNA via intercalation/electrostatic interaction. All the targeted compounds showed more pronounced DNA cleavage activity in the presence of H2O2 and also inhibit the growth of in vitro antibacterial activity against Gram-positive and Gram-negative bacteria.

  4. Insight into the electronic structure of the CP47 antenna protein complex of photosystem II: hole burning and fluorescence study.

    PubMed

    Neupane, Bhanu; Dang, Nhan C; Acharya, Khem; Reppert, Mike; Zazubovich, Valter; Picorel, Rafael; Seibert, Michael; Jankowiak, Ryszard

    2010-03-31

    We report low temperature (T) optical spectra of the isolated CP47 antenna complex from Photosystem II (PSII) with a low-T fluorescence emission maximum near 695 nm and not, as previously reported, at 690-693 nm. The latter emission is suggested to result from three distinct bands: a lowest-state emission band near 695 nm (labeled F1) originating from the lowest-energy excitonic state A1 of intact complexes (located near 693 nm and characterized by very weak oscillator strength) as well as emission peaks near 691 nm (FT1) and 685 nm (FT2) originating from subpopulations of partly destabilized complexes. The observation of the F1 emission is in excellent agreement with the 695 nm emission observed in intact PSII cores and thylakoid membranes. We argue that the band near 684 nm previously observed in singlet-minus-triplet spectra originates from a subpopulation of partially destabilized complexes with lowest-energy traps located near 684 nm in absorption (referred to as AT2) giving rise to FT2 emission. It is demonstrated that varying contributions from the F1, FT1, and FT2 emission bands led to different maxima of fluorescence spectra reported in the literature. The fluorescence spectra are consistent with the zero-phonon hole action spectra obtained in absorption mode, the profiles of the nonresonantly burned holes as a function of fluence, as well as the fluorescence line-narrowed spectra obtained for the Q(y) band. The lowest Q(y) state in absorption band (A1) is characterized by an electron-phonon coupling with the Huang-Rhys factor S of approximately 1 and an inhomogeneous width of approximately 180 cm(-1). The mean phonon frequency of the A1 band is 20 cm(-1). In contrast to previous observations, intact isolated CP47 reveals negligible contribution from the triplet-bottleneck hole, i.e., the AT2 trap. It has been shown that Chls in intact CP47 are connected via efficient excitation energy transfer to the A1 trap near 693 nm and that the position of the

  5. A 20 Years’ Survey of Laser Science and Technology in China. II,

    DTIC Science & Technology

    1980-10-22

    width (nanoseconds) 17 14. Flow rate of cooling water (liters/min.) 15. Life (number of pulses) J% 41 I ~ .’ VA 041 *N*tX** aJ* an. 06. Ut (Xt $ 00) (440M...Working current (Amp) 10. Working voltage (volts) 10. Power (Watts) 12. Flow rate of cooling water 13. Accumulated service life (hours) China’s laser...electrooptic and nonlinear materials. China started the research on these materials relatively early. Xiamen University first investigated amonium dihydrogen

  6. China.

    PubMed

    1983-12-01

    This discussion of China focuses on the following: the people; geography; history (early history, 20th century China, the People's Republic of China; the "Great Leap Forward" and the Sino Soviet Split, the Cultural Revolution, and Mao's death and present directions); government (state structure, Chinese Communist Party, and legal system); education; economy; foreign relations; defense; and relations between China and the US. As of 1982, China's population totaled just over 1.008 billion with an annual growth rate of 1.5%. Life expectancy is 68 years. Government authorities endorsed birth control in the 1950s, played it down in 1958, and began to promote it again in 1962. The present family planning program began in the early 1970s and has become more fully mobilized since 1979. The largest ethnic group is the Han Chinese, who constitute 93.3% of the total population. The People's Republic of China, located in eastern Asia, is almost as large as the European continent. 2/3 of China's area is mountainous or semidesert; only about 1/10 is cultivated. China is the oldest continuous major world civilization with records dating back about 3500 years. Mao's death in September 1976 removed a towering figure from Chinese politics and set off a scramble for succession. The post 11th Party Congress leadership has emphasized economic development and renounced the mass political movements of prior years. Important educational reforms were made in early 1978. Since 1979, the Chinese leadership has moved toward more pragmatic positions in almost all fields. The Chinese government has always been subordinate to the Chinese Communist Party (CCP), its role being to implement party policies. The primary instruments of state power are the State Council, an executive body corresponding to a cabinet, and the NPC, a legislative body. China has made impressive progress in primary education since 1949. About 93% of eligible children are enrolled in 1st grade, though only 65% finish primary

  7. Assessment and provision of rehabilitation among patients hospitalized with acute ischemic stroke in China: Findings from the China National Stroke Registry II.

    PubMed

    Bettger, Janet Prvu; Li, Zixiao; Xian, Ying; Liu, Liping; Zhao, Xingquan; Li, Hao; Wang, Chunxue; Wang, Chunjuan; Meng, Xia; Wang, Anxin; Pan, Yuesong; Peterson, Eric D; Wang, Yilong; Wang, Yongjun

    2017-04-01

    Background Stroke rehabilitation improves functional recovery among stroke patients. However, little is known about clinical practice in China regarding the assessment and provision of rehabilitation among patients with acute ischemic stroke. Aims We examined the frequency and determinants of an assessment for rehabilitation among acute ischemic stroke patients from the China National Stroke Registry II. Methods Data for 19,294 acute ischemic stroke patients admitted to 219 hospitals from June 2012 to January 2013 were analyzed. The multivariable logistic regression model with the generalized estimating equation method accounting for in-hospital clustering was used to identify patient and hospital factors associated with having a rehabilitation assessment during the acute hospitalization. Results Among 19,294 acute ischemic stroke patients, 11,451 (59.4%) were assessed for rehabilitation. Rates of rehabilitation assessment varied among 219 hospitals (IQR 41.4% vs 81.5%). In the multivariable analysis, factors associated with increased likelihood of a rehabilitation assessment ( p < 0.05) included disability prior to stroke, higher NIHSS on admission, receipt of a dysphagia screen, deep venous thrombosis prophylaxis, carotid vessel imaging, longer length of stay, and treatment at a hospital with a higher number of hospital beds (per 100 units). In contrast, patients with a history of atrial fibrillation and hospitals with higher number of annual stroke discharges (per 100 patients) were less likely to receive rehabilitation assessment during the acute stroke hospitalization. Conclusions Rehabilitation assessment among acute ischemic stroke patients was suboptimal in China. Rates varied considerably among hospitals and support the need to improve adherence to recommended care for stroke survivors.

  8. Insight into the Migration Routes of Plutella xylostella in China Using mtCOI and ISSR Markers

    PubMed Central

    Tian, Lixia; Xu, Baoyun; Xie, Wen; Wang, Shaoli; Zhang, Youjun; Wang, Xiangjing; Wu, Qingjun

    2015-01-01

    The larvae of the diamondback moth, Plutella xylostella, cause major economic losses to cruciferous crops, including cabbage, which is an important vegetable crop in China. In this study, we used the mitochondrial COI gene and 11 ISSR markers to characterize the genetic structure and seasonal migration routes of 23 P. xylostella populations in China. Both the mitochondrial and nuclear markers revealed high haplotype diversity and gene flow among the populations, although some degree of genetic isolation was evident between the populations of Hainan Island and other sampling sites. The dominant haplotypes, LX1 and LX2, differed significantly from all other haplotypes both in terms of the number of individuals with those haplotypes and their distributions. Haplotypes that were shared among populations revealed that P. xylostella migrates from the lower reaches of the Yangtze River to northern China and then to northeastern China. Our results also revealed another potential migration route for P. xylostella, i.e., from southwestern China to both northwestern and southern China. PMID:26098353

  9. Insight into the Migration Routes of Plutella xylostella in China Using mtCOI and ISSR Markers.

    PubMed

    Yang, Jiaqiang; Tian, Lixia; Xu, Baoyun; Xie, Wen; Wang, Shaoli; Zhang, Youjun; Wang, Xiangjing; Wu, Qingjun

    2015-01-01

    The larvae of the diamondback moth, Plutella xylostella, cause major economic losses to cruciferous crops, including cabbage, which is an important vegetable crop in China. In this study, we used the mitochondrial COI gene and 11 ISSR markers to characterize the genetic structure and seasonal migration routes of 23 P. xylostella populations in China. Both the mitochondrial and nuclear markers revealed high haplotype diversity and gene flow among the populations, although some degree of genetic isolation was evident between the populations of Hainan Island and other sampling sites. The dominant haplotypes, LX1 and LX2, differed significantly from all other haplotypes both in terms of the number of individuals with those haplotypes and their distributions. Haplotypes that were shared among populations revealed that P. xylostella migrates from the lower reaches of the Yangtze River to northern China and then to northeastern China. Our results also revealed another potential migration route for P. xylostella, i.e., from southwestern China to both northwestern and southern China.

  10. Structural Insights into the Inhibition of Cytosolic 5′-Nucleotidase II (cN-II) by Ribonucleoside 5′-Monophosphate Analogues

    PubMed Central

    Meurillon, Maïa; Jordheim, Lars P.; Dumontet, Charles; Périgaud, Christian; Lionne, Corinne; Peyrottes, Suzanne; Chaloin, Laurent

    2011-01-01

    Cytosolic 5′-nucleotidase II (cN-II) regulates the intracellular nucleotide pools within the cell by catalyzing the dephosphorylation of 6-hydroxypurine nucleoside 5′-monophosphates. Beside this physiological function, high level of cN-II expression is correlated with abnormal patient outcome when treated with cytotoxic nucleoside analogues. To identify its specific role in the resistance phenomenon observed during cancer therapy, we screened a particular class of chemical compounds, namely ribonucleoside phosphonates to predict them as potential cN-II inhibitors. These compounds incorporate a chemically and enzymatically stable phosphorus-carbon linkage instead of a regular phosphoester bond. Amongst them, six compounds were predicted as better ligands than the natural substrate of cN-II, inosine 5′-monophosphate (IMP). The study of purine and pyrimidine containing analogues and the introduction of chemical modifications within the phosphonate chain has allowed us to define general rules governing the theoretical affinity of such ligands. The binding strength of these compounds was scrutinized in silico and explained by an impressive number of van der Waals contacts, highlighting the decisive role of three cN-II residues that are Phe 157, His 209 and Tyr 210. Docking predictions were confirmed by experimental measurements of the nucleotidase activity in the presence of the three best available phosphonate analogues. These compounds were shown to induce a total inhibition of the cN-II activity at 2 mM. Altogether, this study emphasizes the importance of the non-hydrolysable phosphonate bond in the design of new competitive cN-II inhibitors and the crucial hydrophobic stacking promoted by three protein residues. PMID:22174667

  11. Sorption of Nickel(II) on a Calcareous Aridisol Soil, China: Batch, XPS, and EXAFS Spectroscopic Investigations

    PubMed Central

    Qiang, Shirong; Han, Bin; Zhao, Xiaolan; Yang, Yunbo; Shao, Dadong; Li, Ping; Liang, Jianjun; Fan, Qiaohui

    2017-01-01

    The sorption of Ni(II) on a calcareous aridisol (CA) soil, one of the major soil types in northwestern China, was investigated using batch and extended X-ray absorption fine structure (EXAFS) approaches in a 0.01 mol/L NaClO4 solution at different pH values (6.0–10.0), temperatures (25–60 °C) and contact times (2–15 days). Under alkaline conditions, EXAFS analysis showed that the interatomic distances between Ni and O atoms (RNi-O) were approximately 2.04 Å with a typical coordination number (CN) of ~6.0 O atoms in the contact time range from 2 to 15 days. The RNi-Ni (~3.07 Å) suggested that the structure of the Ni(II) adsorbed on the CA soil was basically the same as that of Ni(OH)2(s), while the Ni-Al shell (RNi-Al ~3.16 Å) gradually formed and grew with the increasing contact time. Under weakly acidic conditions, the sorption mechanism of Ni(II) on the CA soil possibly included at least two processes: (i) a fast accumulation dominated by ion exchange and surface complexation and (ii) the formation of a Ni-Al LDH phase over the long term. A high temperature is beneficial to the fixation of Ni(II) on the CA soil and the formation of a Ni-Al LDH. PMID:28440287

  12. Sorption of Nickel(II) on a Calcareous Aridisol Soil, China: Batch, XPS, and EXAFS Spectroscopic Investigations

    NASA Astrophysics Data System (ADS)

    Qiang, Shirong; Han, Bin; Zhao, Xiaolan; Yang, Yunbo; Shao, Dadong; Li, Ping; Liang, Jianjun; Fan, Qiaohui

    2017-04-01

    The sorption of Ni(II) on a calcareous aridisol (CA) soil, one of the major soil types in northwestern China, was investigated using batch and extended X-ray absorption fine structure (EXAFS) approaches in a 0.01 mol/L NaClO4 solution at different pH values (6.0-10.0), temperatures (25-60 °C) and contact times (2-15 days). Under alkaline conditions, EXAFS analysis showed that the interatomic distances between Ni and O atoms (RNi-O) were approximately 2.04 Å with a typical coordination number (CN) of ~6.0 O atoms in the contact time range from 2 to 15 days. The RNi-Ni (~3.07 Å) suggested that the structure of the Ni(II) adsorbed on the CA soil was basically the same as that of Ni(OH)2(s), while the Ni-Al shell (RNi-Al ~3.16 Å) gradually formed and grew with the increasing contact time. Under weakly acidic conditions, the sorption mechanism of Ni(II) on the CA soil possibly included at least two processes: (i) a fast accumulation dominated by ion exchange and surface complexation and (ii) the formation of a Ni-Al LDH phase over the long term. A high temperature is beneficial to the fixation of Ni(II) on the CA soil and the formation of a Ni-Al LDH.

  13. Copper(II) adsorption on the kaolinite(001) surface: Insights from first-principles calculations and molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Kong, Xiang-Ping; Wang, Juan

    2016-12-01

    The adsorption behavior of Cu(II) on the basal hydroxylated kaolinite(001) surface in aqueous environment was investigated by first-principles calculations and molecular dynamics simulations. Structures of possible monodentate and bidentate inner-sphere adsorption complexes of Cu(II) were examined, and the charge transfer and bonding mechanism were analyzed. Combining the binding energy of complex, the radial distribution function of Cu(II) with oxygen and the extended X-ray absorption fine structure data, monodentate complex on site of surface oxygen with "upright" hydrogen and bidentate complex on site of two oxygens (one with "upright" hydrogen and one with "lying" hydrogen) of single Al center have been found to be the major adsorption species of Cu(II). Both adsorption species are four-coordinated with a square planar geometry. The distribution of surface hydroxyls with "lying" hydrogen around Cu(II) plays a key role in the structure and stability of adsorption complex. Upon the Mulliken population analysis and partial density of states, charge transfer occurs with Cu(II) accepting some electrons from both surface oxygens and aqua oxygens, and the bonding Cu 3d-O 2p state filling is primarily responsible for the strong covalent interaction of Cu(II) with surface oxygen.

  14. Titanite-scale insights into multi-stage magma mixing in Early Cretaceous of NW Jiaodong terrane, North China Craton

    NASA Astrophysics Data System (ADS)

    Jiang, Peng; Yang, Kui-Feng; Fan, Hong-Rui; Liu, Xuan; Cai, Ya-Chun; Yang, Yue-Heng

    2016-08-01

    The Early Cretaceous Guojialing-type granodiorites in northwestern Jiaodong terrane carry significant records for strong mantle-crust interaction during the destruction of North China Craton (NCC); however, the definite petrogenetic mechanism and detailed magmatic process remain an enigma. Titanite in igneous rocks can serve as an effective petrogenetic indicator. Here, we present integrated geochronological and geochemical studies on titanites from Guojialing-type granodiorites and their dioritic enclaves to constrain their petrogenesis. Titanites from granodiorites (G-type) and plagioclase-rich dioritic enclaves (E-type-I) present an identical U-Pb age (~ 130 Ma) and an indistinguishable wide range of Zr and total REEs contents, and Th/U ratios. However, these two types of titanites exhibit distinct micro-scale textures and geochemical compositions. G-type titanites are characterized by oscillatory zonings with two Light BSE zones (LBZ) and two or three dark BSE zones, whereas E-type-I titanites are marked by core-mantle-rim zonings. Drastic increase of LREEs, Zr, Hf, and Fe and decrease of Nb, Ta, Al, and F contents are observed in LBZ of G-type titanites, whereas remarkable reduction of LREEs, Zr, and Hf and elevation of F contents are observed from the cores to the mantles of E-type-I titanites. Based on Zr-in-titanite thermometry, G-type titanites are interpreted to have experienced twice notable temperature increase, while E-type-I titanites are inferred to have undergone a rapid cooling process. Furthermore, we suggest that the drastic chemical changes in G-type and E-type-I titanites are ascribed to early-stage magma mixing between a colder felsic magma and a Fe-, REE-rich hotter dioritic magma. Compared to G-type and E-type-I titanites, titanites from plagioclase-poor dioritic enclaves (E-type-II) are characterized by their occurrence in interstitial space and present a relatively younger U-Pb age (~ 128 Ma) and much narrower and lower range of Zr, total

  15. Geometrical and optical benchmarking of copper(II) guanidine-quinoline complexes: insights from TD-DFT and many-body perturbation theory (part II).

    PubMed

    Hoffmann, Alexander; Rohrmüller, Martin; Jesser, Anton; dos Santos Vieira, Ines; Schmidt, Wolf Gero; Herres-Pawlis, Sonja

    2014-11-05

    Ground- and excited-state properties of copper(II) charge-transfer systems have been investigated starting from density-functional calculations with particular emphasis on the role of (i) the exchange and correlation functional, (ii) the basis set, (iii) solvent effects, and (iv) the treatment of dispersive interactions. Furthermore (v), the applicability of TD-DFT to excitations of copper(II) bis(chelate) charge-transfer systems is explored by performing many-body perturbation theory (GW + BSE), independent-particle approximation and ΔSCF calculations for a small model system that contains simple guanidine and imine groups. These results show that DFT and TD-DFT in particular in combination with hybrid functionals are well suited for the description of the structural and optical properties, respectively, of copper(II) bis(chelate) complexes. Furthermore, it is found an accurate theoretical geometrical description requires the use of dispersion correction with Becke-Johnson damping and triple-zeta basis sets while solvent effects are small. The hybrid functionals B3LYP and TPSSh yielded best performance. The optical description is best with B3LYP, whereby heavily mixed molecular transitions of MLCT and LLCT character are obtained which can be more easily understood using natural transition orbitals. An natural bond orbital analysis sheds light on the donor properties of the different donor functions and the intraguanidine stabilization during coordination to copper(I) and (II). Copyright © 2014 Wiley Periodicals, Inc.

  16. New in silico insights into the inhibition of RNAP II by α-amanitin and the protective effect mediated by effective antidotes.

    PubMed

    Garcia, Juliana; Carvalho, Alexandra T P; Dourado, Daniel F A R; Baptista, Paula; de Lourdes Bastos, Maria; Carvalho, Félix

    2014-06-01

    Poisonous α-amanitin-containing mushrooms are responsible for the major cases of fatalities after mushroom ingestion. α-Amanitin is known to inhibit the RNA polymerase II (RNAP II), although the underlying mechanisms are not fully understood. Benzylpenicillin, ceftazidime and silybin have been the most frequently used drugs in the management of α-amanitin poisoning, mostly based on empirical rationale. The present study provides an in silico insight into the inhibition of RNAP II by α-amanitin and also on the interaction of the antidotes on the active site of this enzyme. Docking and molecular dynamics (MD) simulations combined with molecular mechanics-generalized Born surface area method (MM-GBSA) were carried out to investigate the binding of α-amanitin and three antidotes benzylpenicillin, ceftazidime and silybin to RNAP II. Our results reveal that α-amanitin should affects RNAP II transcription by compromising trigger loop (TL) function. The observed direct interactions between α-amanitin and TL residues Leu1081, Asn1082, Thr1083, His1085 and Gly1088 alters the elongation process and thus contribute to the inhibition of RNAP II. We also present evidences that α-amanitin can interact directly with the bridge helix residues Gly819, Gly820 and Glu822, and indirectly with His816 and Phe815. This destabilizes the bridge helix, possibly causing RNAP II activity loss. We demonstrate that benzylpenicillin, ceftazidime and silybin are able to bind to the same site as α-amanitin, although not replicating the unique α-amanitin binding mode. They establish considerably less intermolecular interactions and the ones existing are essential confine to the bridge helix and adjacent residues. Therefore, the therapeutic effect of these antidotes does not seem to be directly related with binding to RNAP II. RNAP II α-amanitin binding site can be divided into specific zones with different properties providing a reliable platform for the structure-based drug design of

  17. Structural characterization of copper(II) binding to alpha-synuclein: Insights into the bioinorganic chemistry of Parkinson's disease.

    PubMed

    Rasia, Rodolfo M; Bertoncini, Carlos W; Marsh, Derek; Hoyer, Wolfgang; Cherny, Dmitry; Zweckstetter, Markus; Griesinger, Christian; Jovin, Thomas M; Fernández, Claudio O

    2005-03-22

    The aggregation of alpha-synuclein (AS) is characteristic of Parkinson's disease and other neurodegenerative synucleinopathies. We demonstrate here that Cu(II) ions are effective in accelerating AS aggregation at physiologically relevant concentrations without altering the resultant fibrillar structures. By using numerous spectroscopic techniques (absorption, CD, EPR, and NMR), we have located the primary binding for Cu(II) to a specific site in the N terminus, involving His-50 as the anchoring residue and other nitrogen/oxygen donor atoms in a square planar or distorted tetragonal geometry. The carboxylate-rich C terminus, originally thought to drive copper binding, is able to coordinate a second Cu(II) equivalent, albeit with a 300-fold reduced affinity. The NMR analysis of AS-Cu(II) complexes reveals the existence of conformational restrictions in the native state of the protein. The metallobiology of Cu(II) in Parkinson's disease is discussed by a comparative analysis with other Cu(II)-binding proteins involved in neurodegenerative disorders.

  18. Surface complexation of heavy metal cations on clay edges: insights from first principles molecular dynamics simulation of Ni(II)

    NASA Astrophysics Data System (ADS)

    Zhang, Chi; Liu, Xiandong; Lu, Xiancai; He, Mengjia; Jan Meijer, Evert; Wang, Rucheng

    2017-04-01

    Aiming at an atomistic mechanism of heavy metal cation complexing on clay surfaces, we carried out systematic first principles molecular dynamics (FPMD) simulations to investigate the structures, free energies and acidity constants of Ni(II) complexes formed on edge surfaces of 2:1 phyllosilicates. Three representative complexes were studied, including monodentate complex on the tbnd SiO site, bidentate complex on the tbnd Al(OH)2 site, and tetradentate complex on the octahedral vacancy where Ni(II) fits well into the lattice. The complexes structures were characterized in detail. Computed free energy values indicate that the tetradentate complex is significantly more stable than the other two. The calculated acidity constants indicate that the tetradentate complex can get deprotonated (pKa = 8.4) at the ambient conditions whereas the other two hardly deprotonate due to extremely high pKa values. By comparing with the 2 Site Protolysis Non Electrostatic Surface Complexation and Cation Exchange (2SPNE SC/CE) model, the vacant site has been assigned to the strong site and the other two to the weak site, respectively. Thus a link has been built between atomistic simulations and macroscopic experiments and it is deduced that this should also apply to other heavy metal cations based on additional simulations of Co(II) and Cu(II) and previous simulations of Fe(II) and Cd(II)). This study forms a physical basis for understanding the transport and fixation of heavy metal elements in many geologic environments.

  19. The Ll.LtrB intron from Lactococcus lactis excises as circles in vivo: insights into the group II intron circularization pathway.

    PubMed

    Monat, Caroline; Quiroga, Cecilia; Laroche-Johnston, Felix; Cousineau, Benoit

    2015-07-01

    Group II introns are large ribozymes that require the assistance of intron-encoded or free-standing maturases to splice from their pre-mRNAs in vivo. They mainly splice through the classical branching pathway, being released as RNA lariats. However, group II introns can also splice through secondary pathways like hydrolysis and circularization leading to the release of linear and circular introns, respectively. Here, we assessed in vivo splicing of various constructs of the Ll.LtrB group II intron from the Gram-positive bacterium Lactococcus lactis. The study of excised intron junctions revealed, in addition to branched intron lariats, the presence of perfect end-to-end intron circles and alternatively circularized introns. Removal of the branch point A residue prevented Ll.LtrB excision through the branching pathway but did not hinder intron circle formation. Complete intron RNA circles were found associated with the intron-encoded protein LtrA forming nevertheless inactive RNPs. Traces of double-stranded head-to-tail intron DNA junctions were also detected in L. lactis RNA and nucleic acid extracts. Some intron circles and alternatively circularized introns harbored variable number of non-encoded nucleotides at their splice junction. The presence of mRNA fragments at the splice junction of some intron RNA circles provides insights into the group II intron circularization pathway in bacteria.

  20. Insights into the Mechanism of Fe(II) Adsorption and Oxidation at Fe-Clay Mineral Surfaces from First-Principles Calculations

    SciTech Connect

    Alexandrov, Vitali Y.; Rosso, Kevin M.

    2013-10-02

    Interfacial reactivity of redox-active iron-bearing mineral surfaces plays a crucial role in many environmental processes including biogeochemical cycling of various elements and contaminants. Herein, we apply density-functional-theory (DFT) calculations to provide atomistic insights into the heterogeneous reaction between aqueous Fe(II) and the Fe-bearing clay mineral nontronite Fe2Si4O10(OH)2 by studying its adsorption mechanism and interfacial Fe(II)-Fe(III) electron transfer (ET) at edge and basal surfaces. We find that edge-bound Fe(II) adsorption complexes at different surface sites (ferrinol, silanol and mixed) may coexist on both (010) and (110) edge facets, with complexes at ferrinol FeO(H) sites being the most energetically favorable and coupled to proton transfer. Calculation of the ET activation energy suggests that interfacial ET into dioctahedral Fe(III) sheets is probable at the clay edges and occurs predominantly but not exclusively through the complexes adsorbed at ferrinol sites and might also involve mixed sites. No clear evidence is found for complexes on basal surface that are compatible with ET through the basal sheet despite this experimentally hypothesized ET interface. This study suggests a strong pH-dependence of Fe(II) surface complexation at basal versus edge facets and highlights the importance of the protonation state of bridging ligands and proton coupled electron transfer to facilitate ET into Fe-rich clay minerals.

  1. Noninvasive genetics provides insights into the population size and genetic diversity of an Amur tiger population in China.

    PubMed

    Wang, Dan; Hu, Yibo; Ma, Tianxiao; Nie, Yonggang; Xie, Yan; Wei, Fuwen

    2016-01-01

    Understanding population size and genetic diversity is critical for effective conservation of endangered species. The Amur tiger (Panthera tigris altaica) is the largest felid and a flagship species for wildlife conservation. Due to habitat loss and human activities, available habitat and population size are continuously shrinking. However, little is known about the true population size and genetic diversity of wild tiger populations in China. In this study, we collected 55 fecal samples and 1 hair sample to investigate the population size and genetic diversity of wild Amur tigers in Hunchun National Nature Reserve, Jilin Province, China. From the samples, we determined that 23 fecal samples and 1 hair sample were from 7 Amur tigers: 2 males, 4 females and 1 individual of unknown sex. Interestingly, 2 fecal samples that were presumed to be from tigers were from Amur leopards, highlighting the significant advantages of noninvasive genetics over traditional methods in studying rare and elusive animals. Analyses from this sample suggested that the genetic diversity of wild Amur tigers is much lower than that of Bengal tigers, consistent with previous findings. Furthermore, the genetic diversity of this Hunchun population in China was lower than that of the adjoining subpopulation in southwest Primorye Russia, likely due to sampling bias. Considering the small population size and relatively low genetic diversity, it is urgent to protect this endangered local subpopulation in China. © 2015 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

  2. Mid-Late Miocene vegetation and environments in Southeast China: Insights from a marine palynological record in northwestern Taiwan

    NASA Astrophysics Data System (ADS)

    Hao, Xiu-dong; Weng, Chengyu; Huang, Chi-Yue; Ouyang, Xu-hong

    2017-05-01

    Taiwan Island represents the exposed accretionary prism developed by eastward subduction of South China Sea (SCS) oceanic lithosphere beneath the Philippine Sea Plate since the middle Miocene. There are many well-documented data about the biostratigraphic correlation, except for palynological studies. Here, we present a new palynological record of mid-Late Miocene deposits from the Chuhuangkeng section, Miaoli, northwestern Taiwan, which reveals a vegetation and paleoelevation reconstruction in Southeast China, during the Middle to Late Miocene, corresponding to the time interval of about 14.5-5.5 Ma. Most samples yielded well-preserved palynomorphs, and the palynological results suggest that the dominant vegetation was the mixed coniferous-broadleaved forests in the Coastal Mountains of Southeast China (CMSC) during the Mid-Late Miocene. Moreover, based on large amounts of Tsuga and Picea pollen, we hypothesized that a subalpine conifer forest then flourished in the CMSC, and the estimated maximum paleoelevation might be up to ∼3000 m above sea level (a.s.l.) during the Mid-Late Miocene, being 1000-1500 m higher than today. These findings offer a new perspective to comprehend the paleotopographic evolution of China and the source area of Taiwan's spruce forests. Additionally, the high abundance of Pinus, Tsuga, Picea pollen and fern spores also suggests an enhancement of the EASM during the Mid-Late Miocene.

  3. Readability and Content Assessment of Informed Consent Forms for Phase II-IV Clinical Trials in China.

    PubMed

    Wen, Gaiyan; Liu, Xinchun; Huang, Lihua; Shu, Jingxian; Xu, Nana; Chen, Ruifang; Huang, Zhijun; Yang, Guoping; Wang, Xiaomin; Xiang, Yuxia; Lu, Yao; Yuan, Hong

    2016-01-01

    To explore the readability and content integrity of informed consent forms (ICFs) used in China and to compare the quality of Chinese local ICFs with that of international ICFs. The length, readability and content of 155 consent documents from phase II-IV drug clinical trials from the Third Xiangya Hospital Ethics Committee from November 2009 to January 2015 were evaluated. Reading difficulty was tested using a readability formula adapted for the Chinese language. An ICF checklist containing 27 required elements was successfully constructed to evaluate content integrity. The description of alternatives to participation was assessed. The quality of ICFs from different sponsorships were also compared. Among the 155 evaluable trials, the ICFs had a median length of 5286 words, corresponding to 7 pages. The median readability score was 4.31 (4.02-4.41), with 63.9% at the 2nd level and 36.1% at the 3rd level. Five of the 27 elements were frequently neglected. The average score for the description of alternatives to participation was 1.06, and 27.7% of the ICFs did not mention any alternatives. Compared with Chinese local ICFs, international ICFs were longer, more readable and contained more of the required elements (P < 0.05). The ICFs used in China were difficult to read for most participants. These forms had poor description of alternatives to participation, and failed to provide a high degree of information disclosure, including an explanation of informed consent, follow-up processing of the data/sample, inclusion/exclusion criteria, double blinding, and unpredictable risks. International ICFs had better readability and content integrity than Chinese local ICFs. More efforts should thus be made to improve the quality of consent documents in China.

  4. Readability and Content Assessment of Informed Consent Forms for Phase II-IV Clinical Trials in China

    PubMed Central

    Wen, Gaiyan; Liu, Xinchun; Huang, Lihua; Shu, Jingxian; Xu, Nana; Chen, Ruifang; Huang, Zhijun; Yang, Guoping; Wang, Xiaomin; Xiang, Yuxia; Lu, Yao; Yuan, Hong

    2016-01-01

    Purpose To explore the readability and content integrity of informed consent forms (ICFs) used in China and to compare the quality of Chinese local ICFs with that of international ICFs. Methods The length, readability and content of 155 consent documents from phase II-IV drug clinical trials from the Third Xiangya Hospital Ethics Committee from November 2009 to January 2015 were evaluated. Reading difficulty was tested using a readability formula adapted for the Chinese language. An ICF checklist containing 27 required elements was successfully constructed to evaluate content integrity. The description of alternatives to participation was assessed. The quality of ICFs from different sponsorships were also compared. Results Among the 155 evaluable trials, the ICFs had a median length of 5286 words, corresponding to 7 pages. The median readability score was 4.31 (4.02–4.41), with 63.9% at the 2nd level and 36.1% at the 3rd level. Five of the 27 elements were frequently neglected. The average score for the description of alternatives to participation was 1.06, and 27.7% of the ICFs did not mention any alternatives. Compared with Chinese local ICFs, international ICFs were longer, more readable and contained more of the required elements (P < 0.05). Conclusion The ICFs used in China were difficult to read for most participants. These forms had poor description of alternatives to participation, and failed to provide a high degree of information disclosure, including an explanation of informed consent, follow-up processing of the data/sample, inclusion/exclusion criteria, double blinding, and unpredictable risks. International ICFs had better readability and content integrity than Chinese local ICFs. More efforts should thus be made to improve the quality of consent documents in China. PMID:27701471

  5. High-resolution structure of human carbonic anhydrase II complexed with acetazolamide reveals insights into inhibitor drug design.

    PubMed

    Sippel, Katherine H; Robbins, Arthur H; Domsic, John; Genis, Caroli; Agbandje-McKenna, Mavis; McKenna, Robert

    2009-10-01

    The crystal structure of human carbonic anhydrase II (CA II) complexed with the inhibitor acetazolamide (AZM) has been determined at 1.1 A resolution and refined to an R(cryst) of 11.2% and an R(free) of 14.7%. As observed in previous CA II-inhibitor complexes, AZM binds directly to the zinc and makes several key interactions with active-site residues. The high-resolution data also showed a glycerol molecule adjacent to the AZM in the active site and two additional AZMs that are adventitiously bound on the surface of the enzyme. The co-binding of AZM and glycerol in the active site demonstrate that given an appropriate ring orientation and substituents, an isozyme-specific CA inhibitor may be developed.

  6. Zn(II) coordination to polyamine macrocycles containing dipyridine units. New insights into the activity of dinuclear Zn(II) complexes in phosphate ester hydrolysis.

    PubMed

    Bazzicalupi, Carla; Bencini, Andrea; Berni, Emanuela; Bianchi, Antonio; Fornasari, Patrizia; Giorgi, Claudia; Valtancoli, Barbara

    2004-10-04

    Zn(II) binding by the dipyridine-containing macrocycles L1-L3 has been analyzed by means of potentiometric measurements in aqueous solutions. These ligands contain one (L1, L2) or two (L3) 2,2'-dipyridine units as an integral part of a polyamine macrocyclic framework having different dimensions and numbers of nitrogen donors. Depending on the number of donors, L1-L3 can form stable mono- and/or dinuclear Zn(II) complexes in a wide pH range. Facile deprotonation of Zn(II)-coordinated water molecules gives mono- and dihydroxo-complexes from neutral to alkaline pH values. The ability of these complexes as nucleophilic agents in hydrolytic processes has been tested by using bis(p-nitrophenyl) phosphate (BNPP) as a substrate. In the dinuclear complexes the two metals play a cooperative role in BNPP cleavage. In the case of the L2 dinuclear complex [Zn(2)L2(OH)(2)](2+), the two metals act cooperatively through a hydrolytic process involving a bridging interaction of the substrate with the two Zn(II) ions and a simultaneous nucleophilic attack of a Zn-OH function at phosphorus; in the case of the dizinc complex with the largest macrocycle L3, only the monohydroxo complex [Zn(2)L3(OH)](3+) promotes BNPP hydrolysis. BNPP interacts with a single metal, while the hydroxide anion may operate a nucleophilic attack. Both complexes display high rate enhancements in BNPP cleavage with respect to previously reported dizinc complexes, due to hydrophobic and pi-stacking interactions between the nitrophenyl groups of BNPP and the dipyridine units of the complexes.

  7. Mechanistic insight into chromium(VI) reduction by oxalic acid in the presence of manganese(II).

    PubMed

    Wrobel, Katarzyna; Corrales Escobosa, Alma Rosa; Gonzalez Ibarra, Alan Alexander; Mendez Garcia, Manuel; Yanez Barrientos, Eunice; Wrobel, Kazimierz

    2015-12-30

    Over the past few decades, reduction of hexavalent chromium (Cr(VI)) has been studied in many physicochemical contexts. In this research, we reveal the mechanism underlying the favorable effect of Mn(II) observed during Cr(VI) reduction by oxalic acid using liquid chromatography with spectrophotometric diode array detector (HPLC-DAD), nitrogen microwave plasma atomic emission spectrometry (HPLC-MP-AES), and high resolution mass spectrometry (ESI-QTOFMS). Both reaction mixtures contained potassium dichromate (0.67 mM Cr(VI)) and oxalic acid (13.3mM), pH 3, one reaction mixture contained manganese sulfate (0.33 mM Mn(II)). In the absence of Mn(II) only trace amounts of reaction intermediates were generated, most likely in the following pathways: (1) Cr(VI)→ Cr(IV) and (2) Cr(VI)+Cr(IV)→ 2Cr(V). In the presence of Mn(II), the active reducing species appeared to be Mn(II) bis-oxalato complex (J); the proposed reaction mechanism involves a one-electron transfer from J to any chromium compound containing CrO bond, which is reduced to CrOH, and the generation of Mn(III) bis-oxalato complex (K). Conversion of K to J was observed, confirming the catalytic role of Mn(II). Since no additional acidification was required, the results obtained in this study may be helpful in designing a new, environmentally friendly strategy for the remediation of environments contaminated with Cr(VI). Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Along-Strike Tectonic Segmentation of the Mesozoic Central Orogenic Belt, China: Insights from the Eastern Qinling Magmatic Syntaxis

    NASA Astrophysics Data System (ADS)

    Ma, C.; Sun, Y.; Li, J.; Xu, W.; magmatism; mineralization

    2011-12-01

    Along-strike tectonic segmentation is an important feature of the active continental margin. However, the tectonic segmentation of collisional orogenic belts is yet not to be well constrained. The Triassic Central Orogenic belt in China extends nearly 5,000 km, and is a collisional belt between the North China and Yangtze cratons. Influenced by the subduction of the paleo-Pacific plate, and the lithospheric thinning of the North China craton, this Orogenic belt is superimposed on multi-stage magmatism and mineralization, showing a typical along-strike segmentation. This paper takes the Eastern Qinling magmatic syntaxis as an example, and attempts to understand the manifestation of the structural segmentation and its formation mechanism. The Eastern Qinling magmatic syntaxis can be divided into two parts bounded by a line extending from the Xiaoqinling - Xiong'ershan region in the southern North China craton to Ankang region in the southern Qinling zone(hereafter referred to Xiao-an line). Both sides of the line have distinct geological and geophysical characteristics. (1) Middle-Late Triassic intrusive rocks are widespread in the west of the Xiao-an line, and their rock types include adakitic and shoshonite-series granitoids, rapakivi granites and a small volume of lamprophyre dykes. Triassic igneous rocks are lack in the east of the Xiao-an line, but the late Jurassic (~153Ma) monzogranites and granodiorite, and early Cretaceous (130-108 Ma) alkali-feldspar granites and syenites are widely distributed in the east, probably in response to the subduction of the paleo-Pacific plate and the lithosphere thinning of the North China craton. (2) In the east of the Xiao-an line, the gold mineralization of quartz-veins and altered-rock took place in the late Mesozoic, while in the west, the carlin-like gold deposits formed in the early Mesozoic.In the east of the line there is late Mesozoic molybdenum ore belt, the largest molybdenum ore belt in China. However, in the west

  9. China’s R&D for Energy Efficient Buildings: Insights for U.S. Cooperation with China

    SciTech Connect

    Yu, Sha; Evans, Meredydd

    2010-04-01

    This report includes an evaluation of China’s current activities and future direction in building energy efficiency R&D and its relevance to DOE’s R&D activities under the Building Technologies Program in the Office of Energy Efficiency and Renewable Energy. The researchers reviewed the major R&D programs in China including the so-called 973 Program, the 863 Program, and the Key Technology R&D Program1 as well as the research activities of major research institutes. The report also reviewed several relevant documents of the Chinese government, websites (including the International Energy Agency and national and local governments in China), newsletters, and financial information listed in the program documents and websites.

  10. Propagated rifting in the Southwest Sub-basin, South China Sea: Insights from 3D analogue modeling

    NASA Astrophysics Data System (ADS)

    Ding, Weiwei; Li, Jiabiao

    2015-04-01

    Most of earth scientists agree that the South China Sea is a rifted marginal sea in the western Pacific. How and when the South China Sea rifted has long been a puzzling question and still debated, especially in the Southwest Sub-basin (SWSB). Analog modeling remains one of the useful tools for testing rift model and process. Here we present and discuss a series of analog modeling experiments designed to investigate the rifting process of the SWSB. Convincing geophysical data were compiled to provide truthful constraints to test the experimental results and interpretations. The results show that rigid tectonic blocks existed in the continental margin, such as the Zhongsha Islands and the Reed Bank, and played an important role in shaping up the continent-ocean boundary (COB) and the coupling between the crust and mantle. Our data suggest that the initial thermal condition and rheologial stratification of the lithosphere under the South China Sea controlled the rifting process of the SWSB. The first-stage seafloor spreading has weakened the lithosphere surrounding the East Sub-basin, and the extension was centered on the deep troughs between the rigid blocks. Rifting bagan in these deep troughs in the east part of the SWSB, and the break-up occurred in localized areas between the rigid blocks. The V-shaped configuration of the SWSB also argues for a propagated rifting model.

  11. Insight into the evolution of avian flight from a new clade of Early Cretaceous ornithurines from China and the morphology of Yixianornis grabaui

    PubMed Central

    Clarke, Julia A; Zhou, Zhonghe; Zhang, Fucheng

    2006-01-01

    In studies of the evolution of avian flight there has been a singular preoccupation with unravelling its origin. By contrast, the complex changes in morphology that occurred between the earliest form of avian flapping flight and the emergence of the flight capabilities of extant birds remain comparatively little explored. Any such work has been limited by a comparative paucity of fossils illuminating bird evolution near the origin of the clade of extant (i.e. ‘modern’) birds (Aves). Here we recognize three species from the Early Cretaceous of China as comprising a new lineage of basal ornithurine birds. Ornithurae is a clade that includes, approximately, comparatively close relatives of crown clade Aves (extant birds) and that crown clade. The morphology of the best-preserved specimen from this newly recognized Asian diversity, the holotype specimen of Yixianornis grabaui Zhou and Zhang 2001, complete with finely preserved wing and tail feather impressions, is used to illustrate the new insights offered by recognition of this lineage. Hypotheses of avian morphological evolution and specifically proposed patterns of change in different avian locomotor modules after the origin of flight are impacted by recognition of the new lineage. The complete articulated holotype specimen of Yixianornis grabaui, from the Early Cretaceous Jiufotang Formation of Liaoning Province, in north-eastern China, arguably the best-preserved basal ornithurine specimen yet discovered, provides the earliest evidence consistent with the presence of extant avian tail feather fanning. PMID:16533313

  12. A cyclic peptide inhibitor of apoC-II peptide fibril formation: mechanistic insight from NMR and molecular dynamics analysis.

    PubMed

    Griffin, Michael D W; Yeung, Levi; Hung, Andrew; Todorova, Nevena; Mok, Yee-Foong; Karas, John A; Gooley, Paul R; Yarovsky, Irene; Howlett, Geoffrey J

    2012-03-09

    The misfolding and aggregation of proteins to form amyloid fibrils is a characteristic feature of several common age-related diseases. Agents that directly inhibit formation of amyloid fibrils represent one approach to combating these diseases. We have investigated the potential of a cyclic peptide to inhibit fibril formation by fibrillogenic peptides from human apolipoprotein C-II (apoC-II). Cyc[60-70] was formed by disulfide cross-linking of cysteine residues added to the termini of the fibrillogenic peptide comprising apoC-II residues 60-70. This cyclic peptide did not self-associate into fibrils. However, substoichiometric concentrations of cyc[60-70] significantly delayed fibril formation by the fibrillogenic, linear peptides apoC-II[60-70] and apoC-II[56-76]. Reduction of the disulfide bond or scrambling the amino acid sequence within cyc[60-70] significantly impaired its inhibitory activity. The solution structure of cyc[60-70] was solved using NMR spectroscopy, revealing a well-defined structure comprising a hydrophilic face and a more hydrophobic face containing the Met60, Tyr63, Ile66 and Phe67 side chains. Molecular dynamics (MD) studies identified a flexible central region within cyc[60-70], while MD simulations of "scrambled" cyc[60-70] indicated an increased formation of intramolecular hydrogen bonds and a reduction in the overall flexibility of the peptide. Our structural studies suggest that the inhibitory activity of cyc[60-70] is mediated by an elongated structure with inherent flexibility and distinct hydrophobic and hydrophilic faces, enabling cyc[60-70] to interact transiently with fibrillogenic peptides and inhibit fibril assembly. These results suggest that cyclic peptides based on amyloidogenic core peptides could be useful as specific inhibitors of amyloid fibril formation.

  13. Insight into the gas-phase structure of a copper(II) L-histidine complex, the agent used to treat Menkes disease.

    PubMed

    Ziegler, Blake E; Marta, Richard A; Burt, Michael B; McMahon, Terry B

    2014-03-03

    Copper(II) L-histidine is used in the treatment of a rare neurological disease called Menkes disease. An infrared multiple photon dissociation (IRMPD) vibrational spectrum of the gas-phase copper(II) L-histidine complex has been obtained. This spectrum was compared to lowest-energy computational spectra obtained at the B3LYP/6-311+G** level of theory. Two species, CuHis1 and CuHis2, are very close in Gibbs free energy, and both have computed vibrational spectra in good agreement with the experimentally observed IRMPD spectrum. The first structure exhibits four histidine-copper interactions in the same plane and a fifth out-of-plane interaction. The second structure exhibits four histidine-copper interactions in the same plane. The fact that the experimental and computational spectra are found to be in good agreement adds considerable insight into the gas-phase structure of the copper(II) L-histidine complex.

  14. History and update of HTLV infection in China.

    PubMed

    Du, Jialiang; Chen, Changrong; Gao, Jiamei; Xie, Jinzhen; Rong, Xia; Xu, Xiaoxun; Wang, Yongjun; Wang, Fang; Li, Jianbin; Lu, Zhiming; Guo, Weipeng; Li, Guoliang; Wang, Zhongying; Xu, Dongfeng; Weng, Jianfeng; Zhao, Zhijian; Weng, Wei; Li, Haoru; Du, Yong; Li, Song; Zhen, Chaohui; Liu, Baolin; Guo, Tai

    2014-10-13

    Human T-lymphotropic virus (HTLV) infection is a high risk factor for lymphoproliferative, inflammatory, and infectious disorders. The epidemiology of HTLV-I, II in industrialized countries has been intensively investigated, and mandatory screening of blood supplies for HTLV-I/II was implemented in mid-1980s in most developed and several developing countries, yet no expanding investigation has been executed in China so far and also been considered as a non-endemic region. However, Gessain et al. reported that the current number of HTLV carriers in the highly populated China is very probably much higher. Therefore, gaining insight into the epidemiology of HTLV infections is essential for avoiding HTLV-induced risk. To introduce the history and renew the HTLV infection in China, we reviewed literatures and conducted an investigation among blood donors in 9 provinces in China. Concluded from the historical and renewed data, the HTLV screen in China can be divided into three stages.

  15. New assemly model of Jiangnan Orogen: insight from detrital zircon geochronology of pre-Cretaceous strata, South China

    NASA Astrophysics Data System (ADS)

    Su, J.; Dong, S.

    2013-12-01

    The Jiangnan Orogen separates the Yangtze and Cathaysian Blocks in South China and provokes a longstanding debate on the amalgamation history between the two Blocks. The assembly of the two Blocks is termed Sibao orogeny marked by undeformed Late Neoproterozoic strata (Banxi Group) overlying on the deformed Early Neoproterozoic strata (Lengjiaxi Group) in China. Detrital zircons can provide critical links in recognizing the source history of a deposit, sedimentary dispersal systems and tectonic reconstructions. Therefore, fifteen sandstone samples taken from pre-Cretaceous strata of Yangtze Block are analyzed to constrain the evolution of the South China Block (SCB), especially the assembly between Yangtze and Cathaysia Blocks. The results show that the detrital zircons from the Neoproterozoic Lengjiaxi Group (ca. 830 Ma) near the boundary of large detachment fault of Hengshan have similar age populations with that in the other sites of the Jiangnan Orogen, different from that of the Kunyang and Dahongshan Groups (>960 Ma) in the southwestern margin of the Yangtze Block. The detrital zircons from Paleozoic samples have similar age populations with that in the Cathaysia Block. We infer that they originate from the Cathaysia Block, together with paleogeography, paleocurrent and former research. The detrital zircons of middle-late Jurassic sandstones in southwestern and central Yangtze yield dominant populations at 2.0-1.7 Ga and subordinate Groups of 2.6-2.4Ga, 0.7-0.8Ga and 0.6-0.4Ga. The provenance of late Triassic strata may be derived from southern Yangtze and North China Block due to the collisions among the Indosina, South China and North China Blocks, whereas the Jurassic sediments may be partly derived from uplift erosion of Jiangnan Orogen due to intra-continental orogeny induced by pacific subduction towards Eurasia Plate. The tectothermal event occurred at ca. 1.1-0.8 Ga has long been attributed to the assembly or breakup of Yangtze and Cathaysia Blocks

  16. Structural insights into the coordination and extraction of Pb(II) by disulfonamide ligands derived from o-phenylenediamine.

    PubMed

    Alvarado, Robert J; Rosenberg, Jay M; Andreu, Aileen; Bryan, Jeffrey C; Chen, Wei-Zhong; Ren, Tong; Kavallieratos, Konstantinos

    2005-10-31

    The o-phenylenediamine-derived disulfonamide ligands 1 and 2 complex and efficiently extract Pb(II) from water into 1,2-dichloroethane via ion-exchange, in combination with 2,2'-bipyridine (97.5% and 95.0%, respectively, for 1:1 ligand-to-Pb ratios). The corresponding Pb(II)-sulfonamido binary complexes of ligands 1 and 2 (3 and 4, respectively), and ternary complexes with 2,2'-bipyridine (5 and 6, respectively), were isolated and characterized. (1)H NMR spectra of the organic phases after extraction show the formation of ternary Pb-sulfonamido-bipy complexes. X-ray characterization of 3, 4, and the ternary complex 5 consistently demonstrates four primary coordination sites and a stereochemically active lone pair on Pb. The X-ray structure of 3 shows a pseudo trigonal bipyramidal configuration on Pb, with the lone pair occupying one of the equatorial sites, and the formation of an unusual "hemidirected" coordination polymer via axial S=O-Pb coordination. The same axial S=O-Pb coordination pattern with two DMSO molecules is observed in the structure of 4.[2(CH(3))(2)SO)], thus rationalizing the high solubility of the binary complexes in strongly coordinating solvents. In contrast, the X-ray structure of the ternary complex 5 reveals a distorted four-coordinate configuration with only weak S=O-Pb coordination leading to dimer formation, thus explaining its higher solubility in weakly coordinating solvents. FT-IR spectroscopy confirms the X-ray data, since the ligand nu(S)(=)(O) stretching frequencies shift to lower values in the binary Pb(II)-sulfonamido complexes and are again altered upon formation of the ternary Pb(II)-sulfonamido-bipy complexes, as would be expected for 2,2'-bipy complexation and hindered S=O-Pb coordination.

  17. New insights on Late Quaternary Asian palaeomonsoon variability and the timing of the Last Glacial Maximum in southwestern China

    NASA Astrophysics Data System (ADS)

    Cook, Charlotte G.; Jones, Richard T.; Langdon, Peter G.; Leng, Melanie J.; Zhang, Enlou

    2011-04-01

    A ˜6.35 m core (06SD) was retrieved from Lake Shudu, Yunnan Province, China. The sediments spanning the period ˜22.6-10.5 kcal. yr BP (6.35-1.44 m) were analysed using a combination of variables including pollen, charcoal, particle size, magnetic susceptibility and loss-on-ignition. The resulting palaeorecord provides a high-resolution reconstruction of Late Pleistocene to Early Holocene climatic and environmental changes in southwestern China. Our findings indicate that from c. 22.6 to 17.7 kcal. yr BP, vegetation assemblages were primarily aligned to sparse xerophytic grassland/tundra or cold-tolerant boreal Pinus forest, indicating that climatic conditions in southwestern China were cold and dry. However, from c. 17.7 to 17.4 kcal. yr BP, the Lake Shudu record is punctuated by marked environmental changes. These include the establishment of denser vegetation cover, a marked expansion of boreal Pinus forest and enhanced hydrological activity in the catchment over centennial timescales, perhaps suggesting that stepwise variations in the Asian Monsoon were triggering fundamental environmental changes over sub-millennial timescales. Thereafter, the pollen record captures a period of environmental instability reflected in fluctuations across all of the variables, which persists until c. 17.1 kcal. yr BP. After c. 17.1 kcal. yr BP, the expansion of steppe vegetation cover and cold-cool mixed forest consisting of mesophilous vegetation such as Tsuga and Picea, thermophilous trees including Ulmus and deciduous Quercus inferred from the Lake Shudu pollen record point to the establishment of warmer, wetter and perhaps more seasonal conditions associated with a strengthening Asian Summer Monsoon during the shift from Pleistocene to Holocene climatic conditions.

  18. Insight into invertebrate defensin mechanism of action: oyster defensins inhibit peptidoglycan biosynthesis by binding to lipid II.

    PubMed

    Schmitt, Paulina; Wilmes, Miriam; Pugnière, Martine; Aumelas, André; Bachère, Evelyne; Sahl, Hans-Georg; Schneider, Tanja; Destoumieux-Garzón, Delphine

    2010-09-17

    Three oyster defensin variants (Cg-Defh1, Cg-Defh2, and Cg-Defm) were produced as recombinant peptides and characterized in terms of activities and mechanism of action. In agreement with their spectrum of activity almost specifically directed against Gram-positive bacteria, oyster defensins were shown here to be specific inhibitors of a bacterial biosynthesis pathway rather than mere membrane-active agents. Indeed, at lethal concentrations, the three defensins did not compromise Staphylococcus aureus membrane integrity but inhibited the cell wall biosynthesis as indicated by the accumulation of the UDP-N-acetylmuramyl-pentapeptide cell wall precursor. In addition, a combination of antagonization assays, thin layer chromatography, and surface plasmon resonance measurements showed that oyster defensins bind almost irreversibly to the lipid II peptidoglycan precursor, thereby inhibiting the cell wall biosynthesis. To our knowledge, this is the first detailed analysis of the mechanism of action of antibacterial defensins produced by invertebrates. Interestingly, the three defensins, which were chosen as representative of the oyster defensin molecular diversity, bound differentially to lipid II. This correlated with their differential antibacterial activities. From our experimental data and the analysis of oyster defensin sequence diversity, we propose that oyster defensin activity results from selective forces that have conserved residues involved in lipid II binding and diversified residues at the surface of oyster defensins that could improve electrostatic interactions with the bacterial membranes.

  19. Raman study of in vivo synthesized Zn(II)-metallothionein complexes: structural insight into metal clusters and protein folding.

    PubMed

    Torreggiani, Armida; Domènech, Jordi; Atrian, Sílvia; Capdevila, Mercè; Tinti, Anna

    2008-12-01

    Metallothioneins (MTs) are metal-chelating peptides that play an active role in zinc homeostasis. The participation of metal ligands other than cysteines and the presence of secondary structure elements in metal-MT complexes are fairly unknown, especially in nonvertebrate MTs. Here, four Zn(II) complexes of invertebrate MTs (mollusc, insect, nematode, and echinoderm) and the Zn(II)-MT complex of the mammalian MT1 isoform, heterologously synthesized in E. coli, were studied by analytic and spectroscopic techniques. By Raman and circular dichroism spectroscopy, new structural informations were obtained. The five analyzed MT isoforms consist largely of beta-turns with the near exclusion of alpha-helical segments. Raman spectroscopy was revealed as an useful tool, providing information about the state of the cysteine sulfur atoms (metal coordinated and oxidized), the participation of histidine in metal coordination, and the molecular environment of tyrosine residues. In all the five Zn(II)-MT studied samples, acid-labile sulfide anions were found as nonproteic ligands, since sulfide-containing and sulfide-devoid species coexisted in the corresponding preparations. Significantly, Raman bands useful as markers of sulfide bridging ligands were identified. Overall, this work illustrates how the combination of analytical and spectroscopic techniques can be a very informative approach for the analysis of in vivo-synthesized metal-MT complexes, providing new data on the metal binding behavior of MTs from the most diverse organisms.

  20. The solar chromosphere at high resolution with IBIS. I. New insights from the Ca II 854.2 nm line

    NASA Astrophysics Data System (ADS)

    Cauzzi, G.; Reardon, K. P.; Uitenbroek, H.; Cavallini, F.; Falchi, A.; Falciani, R.; Janssen, K.; Rimmele, T.; Vecchio, A.; Wöger, F.

    2008-03-01

    Context: The chromosphere remains a poorly understood part of the solar atmosphere, as current modeling and observing capabilities are still ill-suited to investigating its fully 3-dimensional nature in depth. In particular, chromospheric observations that can preserve high spatial and temporal resolution while providing spectral information over extended fields of view are still very scarce. Aims: In this paper, we seek to establish the suitability of imaging spectroscopy performed in the Ca II 854.2 nm line as a means of investigating the solar chromosphere at high resolution. Methods: We utilize monochromatic images obtained with the Interferometric BIdimensional Spectrometer (IBIS) at multiple wavelengths within the Ca II 854.2 nm line and over several quiet areas. We analyze both the morphological properties derived from narrow-band monochromatic images and the average spectral properties of distinct solar features such as network points, internetwork areas, and fibrils. Results: The spectral properties derived over quiet-Sun targets are in full agreement with earlier results obtained with fixed-slit spectrographic observations, highlighting the reliability of the spectral information obtained with IBIS. Furthermore, the very narrowband IBIS imaging reveals very clearly the dual nature of the Ca II 854.2 nm line. Its outer wings gradually sample the solar photosphere, while the core is a purely chromospheric indicator. The latter displays a wealth of fine structures including bright points akin to the Ca II H{2V} and K{2V} grains, and as fibrils originating from even the smallest magnetic elements. The fibrils occupy a large fraction of the observed field of view, even in the quiet regions, and clearly outline atmospheric volumes with different dynamical properties, strongly dependent on the local magnetic topology. This highlights how 1D models stratified along the vertical direction can provide only a very limited representation of the actual chromospheric

  1. Iron isotope fractionation between aqueous Fe(II) and goethite revisited: New insights based on a multi-direction approach to equilibrium and isotopic exchange rate modification

    NASA Astrophysics Data System (ADS)

    Frierdich, Andrew J.; Beard, Brian L.; Reddy, Thiruchelvi R.; Scherer, Michelle M.; Johnson, Clark M.

    2014-08-01

    The Fe isotope compositions of naturally occurring Fe oxide minerals provide insights into biogeochemical processes that occur in modern and ancient environments. Key to understanding isotopic variations in such minerals is knowledge of the equilibrium Fe isotope fractionation factors between common minerals and aqueous Fe species. Because experimental measurements of isotopic fractionation may reflect a combination of kinetic and equilibrium fractionations during rapid dissolution and precipitation, even in experiments that employ the three-isotope method, assessment of the attainment of equilibrium is often difficult. Here, we re-examine Fe isotope exchange, via a 57Fe tracer, and natural mass-dependent fractionation, through changes in initial 56Fe/54Fe ratios, between aqueous Fe(II) (Fe(II)aq) and goethite. This approach uses the three-isotope method, but is distinct in its evaluation of kinetic isotope fractionation and the attainment of equilibrium by: (i) employing a multi-direction approach to equilibrium at 22 °C via reaction of three Fe(II)aq solutions that had different initial 56Fe/54Fe ratios, (ii) conducting isotopic exchange experiments at elevated temperature (50 °C), and (iii) modifying the rate of isotopic exchange through a combination of trace-element substitutions and particle coarsening to evaluate corresponding temporal changes in fractionation trajectories that may reflect changing instantaneous fractionation factors. We find that rapid isotopic exchange produces kinetic isotope effects between Fe(II)aq and goethite, which shifts the 56Fe/54Fe ratios of Fe(II)aq early in reactions toward that of goethite, indicating that the instantaneous Fe(II)aq-goethite fractionation factor under kinetic conditions is small. Importantly, however, this kinetic fractionation is “erased” with continued reaction, and this is evident by the congruence for multiple-exchange trajectories of distinct initial Fe(II)aq solutions toward the same final value

  2. Should Exotic Eucalyptus be Planted in Subtropical China: Insights from Understory Plant Diversity in Two Contrasting Eucalyptus Chronosequences

    NASA Astrophysics Data System (ADS)

    Wu, Jianping; Fan, Houbao; Liu, Wenfei; Huang, Guomin; Tang, Jianfu; Zeng, Ruijin; Huang, Jing; Liu, Zhanfeng

    2015-11-01

    Although Eucalyptus is widely planted in South China, whose effects on native biodiversity are unclear. The objective of this study was to quantify the richness and composition of understory plants in two contrasting Eucalyptus chronosequences in South China. One was in Zhangzhou City with plantation age of 2, 4, and 6 years after clear-cutting Chinese fir forests, while the other was in Heshan City with plantation age of 2, 3, and 24 years that reforested on barren lands. Results showed that the richness of understory plants and functional groups was not significantly altered in the Zhangzhou chronosequence, while increased in the 24-year-old plantations, with a significantly larger proportion of woody plants than the younger plantations for the Heshan chronosequence. Moreover, a higher richness of woody plants accompanied by a lower richness of herbaceous species was detected in the Zhangzhou chronosequence compared with the Heshan one. To balance the need for pulp production and plant diversity conservation, we suggest that intercropping approaches between exotic Eucalyptus plantations and native forests should be considered in the fast rotation Eucalyptus plantations. However, Eucalyptus plantations may be used as pioneer species to sustain ecosystem functioning for the degraded lands.

  3. Should Exotic Eucalyptus be Planted in Subtropical China: Insights from Understory Plant Diversity in Two Contrasting Eucalyptus Chronosequences.

    PubMed

    Wu, Jianping; Fan, Houbao; Liu, Wenfei; Huang, Guomin; Tang, Jianfu; Zeng, Ruijin; Huang, Jing; Liu, Zhanfeng

    2015-11-01

    Although Eucalyptus is widely planted in South China, whose effects on native biodiversity are unclear. The objective of this study was to quantify the richness and composition of understory plants in two contrasting Eucalyptus chronosequences in South China. One was in Zhangzhou City with plantation age of 2, 4, and 6 years after clear-cutting Chinese fir forests, while the other was in Heshan City with plantation age of 2, 3, and 24 years that reforested on barren lands. Results showed that the richness of understory plants and functional groups was not significantly altered in the Zhangzhou chronosequence, while increased in the 24-year-old plantations, with a significantly larger proportion of woody plants than the younger plantations for the Heshan chronosequence. Moreover, a higher richness of woody plants accompanied by a lower richness of herbaceous species was detected in the Zhangzhou chronosequence compared with the Heshan one. To balance the need for pulp production and plant diversity conservation, we suggest that intercropping approaches between exotic Eucalyptus plantations and native forests should be considered in the fast rotation Eucalyptus plantations. However, Eucalyptus plantations may be used as pioneer species to sustain ecosystem functioning for the degraded lands.

  4. The Cyanobacteria-Dominated Sponge Dactylospongia elegans in the South China Sea: Prokaryotic Community and Metagenomic Insights.

    PubMed

    Gao, Zhao-Ming; Zhou, Guo-Wei; Huang, Hui; Wang, Yong

    2017-01-01

    The South China Sea is a special reservoir of sponges of which prokaryotic communities are less studied. Here, a new record of the sponge Dactylospongia elegans is reported near the coast of Jinqing Island in the South China Sea, and its prokaryotic community is comprehensively investigated. Sponge specimens displayed lower microbial diversity compared with surrounding seawater. At the phylum level, prokaryotic communities were consistently dominated by Proteobacteria, followed by Cyanobacteria, Chloroflexi, Acidobacteria, Actinobacteria, Gemmatimonadetes, Thaumarchaeota, and Poribacteria. Operational taxonomic unit (OTU) analysis alternatively showed that the most abundant symbiont was the sponge-specific cyanobacterial species "Candidatus Synechococcus spongiarum," followed by OTUs belonging to the unidentified Chloroflexi and Acidobacteria. Phylogenetic tree based on 16S-23S internal transcribed spacer regions indicated that the dominated cyanobacterial OTU represented a new clade of "Ca. Synechococcus spongiarum." More reliable metagenomic data further revealed that poribacterial symbionts were highly abundant and only secondary to the cyanobacterial symbiont. One draft genome for each of the Cyanobacteria, Chloroflexi and Acidobacteria and three poribacterial genomes were extracted from the metagenomes. Among them, genomes affiliated with the Chloroflexi and Acidobacteria were reported for the first time in sponge symbionts. Eukaryotic-like domains were found in all the binned genomes, indicating their potential symbiotic roles with the sponge host. The high quality of the six recovered genomes of sponge symbionts from the sponge D. elegans makes it possible to understand their symbiotic roles and interactions with the sponge host as well as among one another.

  5. Insights into water coordination associated with the Cu(II)/Cu(I) electron transfer at a biomimetic Cu centre.

    PubMed

    Porras Gutiérrez, Ana Gabriela; Zeitouny, Joceline; Gomila, Antoine; Douziech, Bénédicte; Cosquer, Nathalie; Conan, Françoise; Reinaud, Olivia; Hapiot, Philippe; Le Mest, Yves; Lagrost, Corinne; Le Poul, Nicolas

    2014-05-07

    The coordination properties of the biomimetic complex [Cu(TMPA)(H2O)](CF3SO3)2 (TMPA = tris(2-pyridylmethyl)amine) have been investigated by electrochemistry combined with UV-Vis and EPR spectroscopy in different non-coordinating media including imidazolium-based room-temperature ionic liquids, for different water contents. The solid-state X-ray diffraction analysis of the complex shows that the cupric centre lies in a N4O coordination environment with a nearly perfect trigonal bipyramidal geometry (TBP), the water ligand being axially coordinated to Cu(II). In solution, the coordination geometry of the complex remains TBP in all media. Neither the triflate ion nor the anions of the ionic liquids were found to coordinate the copper centre. Cyclic voltammetry in all media shows that the decoordination of the water molecule occurs upon monoelectronic reduction of the Cu(II) complex. Back-coordination of the water ligand at the cuprous state can be detected by increasing the water content and/or decreasing the timescale of the experiment. Numerical simulations of the voltammograms allow the determination of kinetics and thermodynamics for the water association-dissociation mechanism. The resulting data suggest that (i) the binding/unbinding of water at the Cu(I) redox state is relatively slow and equilibrated in all media, and (ii) the binding of water at Cu(I) is somewhat faster in the ionic liquids than in the non-coordinating solvents, while the decoordination process is weakly sensitive to the nature of the solvents. These results suggest that ionic liquids favour water exchange without interfering with the coordination sphere of the metal centre. This makes them promising media for studying host-guest reactions with biomimetic complexes.

  6. Insights into characteristics, sources, and evolution of submicron aerosols during harvest seasons in the Yangtze River delta region, China

    NASA Astrophysics Data System (ADS)

    Zhang, Y. J.; Tang, L. L.; Wang, Z.; Yu, H. X.; Sun, Y. L.; Liu, D.; Qin, W.; Canonaco, F.; Prévôt, A. S. H.; Zhang, H. L.; Zhou, H. C.

    2015-02-01

    Atmospheric submicron particulate matter (PM1) is one of the most significant pollution components in China. Despite its current popularity in the studies of aerosol chemistry, the characteristics, sources and evolution of atmospheric PM1 species are still poorly understood in China, particularly for the two harvest seasons, namely, the summer wheat harvest and autumn rice harvest. An Aerodyne Aerosol Chemical Speciation Monitor (ACSM) was deployed for online monitoring of PM1 components during summer and autumn harvest seasons in urban Nanjing, in the Yangtze River delta (YRD) region of China. PM1 components were shown to be dominated by organic aerosol (OA, 39 and 41%) and nitrate (23 and 20%) during the harvest seasons (the summer and autumn harvest). Positive matrix factorization (PMF) analysis of the ACSM OA mass spectra resolved four OA factors: hydrocarbon-like mixed with cooking-related OA (HOA + COA), fresh biomass-burning OA (BBOA), oxidized biomass-burning-influenced OA (OOA-BB), and highly oxidized OA (OOA); in particular the oxidized BBOA contributes ~80% of the total BBOA loadings. Both fresh and oxidized BBOA exhibited apparent diurnal cycles with peak concentration at night, when the high ambient relative humidity and low temperature facilitated the partitioning of semi-volatile organic species into the particle phase. The fresh BBOA concentrations for the harvests are estimated as BBOA = 15.1 × (m/z 60-0.26% × OA), where m/z (mass-to-charge ratio) 60 is a marker for levoglucosan-like species. The (BBOA + OOA-BB)/ΔCO, (ΔCO is the CO minus background CO), decreases as a function of f44 (fraction of m/z 44 in OA signal), which might indicate that BBOA was oxidized to less volatile OOA, e.g., more aged and low volatility OOA (LV-OOA) during the aging process. Analysis of air mass back trajectories indicates that the high BB pollutant concentrations are linked to the air masses from the western (summer harvest) and southern (autumn harvest) areas.

  7. Direct observations of organic aerosols in common wintertime hazes in North China: insights into direct emissions from Chinese residential stoves

    NASA Astrophysics Data System (ADS)

    Chen, Shurui; Xu, Liang; Zhang, Yinxiao; Chen, Bing; Wang, Xinfeng; Zhang, Xiaoye; Zheng, Mei; Chen, Jianmin; Wang, Wenxing; Sun, Yele; Fu, Pingqing; Wang, Zifa; Li, Weijun

    2017-01-01

    Many studies have focused on the physicochemical properties of aerosol particles in unusually severe haze episodes in North China instead of the more frequent and less severe hazes. Consistent with this lack of attention, the morphology and mixing state of organic matter (OM) particles in the frequent light and moderate (L & M) hazes in winter in the North China Plain (NCP) have not been examined, even though OM dominates these fine particles. In the present work, morphology, mixing state, and size of organic aerosols in the L & M hazes were systematically characterized using transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy, atomic force microscopy, and nanoscale secondary ion mass spectrometer, with the comparisons among an urban site (Jinan, S1), a mountain site (Mt. Tai, S2), and a background island site (Changdao, S3) in the same hazes. Based on their morphologies, the OM particles were divided into six different types: spherical (type 1), near-spherical (type 2), irregular (type 3), domelike (type 4), dispersed-OM (type 5), and OM-coating (type 6). In the three sampling sites, types 1-3 of OM particles were most abundant in the L & M hazes and most of them were internally mixed with non-OM particles. The abundant near-spherical OM particles with higher sphericity and lower aspect ratio indicate that these primary OM particles formed in the cooling process after polluted plumes were emitted from coal combustion and biomass burning. Based on the Si-O-C ratio in OM particles, we estimated that 71 % of type 1-3 OM particles were associated with coal combustion. Our result suggests that coal combustion in residential stoves was a widespread source from urban to rural areas in NCP. Average OM thickness which correlates with the age of the air masses in type 6 particles only slightly increased from S1 to S2 to S3, suggesting that the L & M hazes were usually dry (relative humidity < 60 %) with weak photochemistry and

  8. Prevalence, incidence, and lifetime risk of atrial fibrillation in China: new insights into the global burden of atrial fibrillation.

    PubMed

    Guo, Yutao; Tian, Yingchun; Wang, Hao; Si, Quanjin; Wang, Yutang; Lip, Gregory Y H

    2015-01-01

    Much of the epidemiology of atrial fibrillation (AF) is based on data from Western populations. Despite the huge population of Asia, data on the clinical epidemiology of AF in Asian countries are limited. The current study aimed to investigate the prevalence and incidence of newly diagnosed (ie, incident) AF, as well as lifetime risk, in China and to determine the clinical risk factors contributing to its development. Using a medical insurance database involving > 10 million individuals for the years 2001 to 2012 in the southwest of China, trends in incident AF were calculated using Kaplan-Meier analysis and Cox regression. The usefulness of the CHADS2 (congestive heart failure, hypertension, age, diabetes, stroke [doubled]) and CHA2DS2-VASc (congestive heart failure, hypertension, age ≥ 75 [doubled], diabetes, stroke [doubled], vascular disease, age 65-74, and sex category [female]) scores was tested in predicting the occurrence of incident AF. A total of 471,446 individuals (aged ≥ 20 years) were studied, with 1,924,975 person-years of experience. We identified 921 patients with incident AF (62% male; mean age, 62 years). The prevalence of incident AF in subjects aged ≥ 20 years was 0.2 per 100 people, with an incidence of AF of 0.05 per 100 person-years overall. Over an 11-year period, the prevalence of AF increased 20-fold, whereas AF-related stroke increased 13-fold. The lifetime risk of AF was approximately one in five among Chinese adults, and it increased with advancing age. The CHA2DS2-VASc score was superior to the CHADS2 score in predicting the risk of incident AF in our Chinese population (DeLong test, Z = 6.621, P < .001). The AF burden, as well as the risk of AF-related stroke, has increased significantly over the past 11 years in the southwest of China. The public health burden of AF and its complications are greatest in the very elderly, with major implications for health-care systems given the global burden of this common arrhythmia.

  9. Non-Porous Iron(II)-Based Sensor: Crystallographic Insights into a Cycle of Colorful Guest-Induced Topotactic Transformations.

    PubMed

    Rodríguez-Jiménez, Santiago; Feltham, Humphrey L C; Brooker, Sally

    2016-11-21

    Materials capable of sensing volatile guests at room temperature by an easily monitored set of outputs are of great appeal for development as chemical sensors of small volatile organics and toxic gases. Herein the dinuclear iron(II) complex, [Fe(II)2 (L)2 (CH3 CN)4 ](BF4 )4 ⋅2 CH3 CN (1) [L=4-(4-methylphenyl)-3-(3-pyridazinyl)-5-pyridyl-4H-1,2,4-triazole], is shown to undergo reversible single-crystal-to-single-crystal (SCSC) transformations upon exposure to vapors of different guests: 1 (MeCN)⇌2 (EtOH)→3 (H2 O)⇌1 (MeCN). Whilst 1 and 2 remain dimetallic, SCSC to 3 involves conversion to a 1D polymeric chain (due to a change in L bridging mode), which, remarkably, can undergo SCSC de-polymerization, reforming dimetallic 1. Additionally, SC-XRD studies of two ordered transient forms, 1TF3 and 2TF3, confirm that guest exchange occurs by diffusion of the new guests into the non-porous lattices as the old guests leave. These reversible SCSC events also induce color and magnetic responses. Indeed dark red 1 is spin crossover active (T1/2 ↓ 356 K; T1/2 ↑ 369 K), whilst orange 2 and yellow 3 remain high spin. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. The Cyanobacteria-Dominated Sponge Dactylospongia elegans in the South China Sea: Prokaryotic Community and Metagenomic Insights

    PubMed Central

    Gao, Zhao-Ming; Zhou, Guo-Wei; Huang, Hui; Wang, Yong

    2017-01-01

    The South China Sea is a special reservoir of sponges of which prokaryotic communities are less studied. Here, a new record of the sponge Dactylospongia elegans is reported near the coast of Jinqing Island in the South China Sea, and its prokaryotic community is comprehensively investigated. Sponge specimens displayed lower microbial diversity compared with surrounding seawater. At the phylum level, prokaryotic communities were consistently dominated by Proteobacteria, followed by Cyanobacteria, Chloroflexi, Acidobacteria, Actinobacteria, Gemmatimonadetes, Thaumarchaeota, and Poribacteria. Operational taxonomic unit (OTU) analysis alternatively showed that the most abundant symbiont was the sponge-specific cyanobacterial species “Candidatus Synechococcus spongiarum,” followed by OTUs belonging to the unidentified Chloroflexi and Acidobacteria. Phylogenetic tree based on 16S-23S internal transcribed spacer regions indicated that the dominated cyanobacterial OTU represented a new clade of “Ca. Synechococcus spongiarum.” More reliable metagenomic data further revealed that poribacterial symbionts were highly abundant and only secondary to the cyanobacterial symbiont. One draft genome for each of the Cyanobacteria, Chloroflexi and Acidobacteria and three poribacterial genomes were extracted from the metagenomes. Among them, genomes affiliated with the Chloroflexi and Acidobacteria were reported for the first time in sponge symbionts. Eukaryotic-like domains were found in all the binned genomes, indicating their potential symbiotic roles with the sponge host. The high quality of the six recovered genomes of sponge symbionts from the sponge D. elegans makes it possible to understand their symbiotic roles and interactions with the sponge host as well as among one another. PMID:28790992

  11. Dyke swarms and their role in the genesis of world-class gold deposits: Insights from the Jiaodong peninsula, China

    NASA Astrophysics Data System (ADS)

    Li, Lin; Li, Sheng-Rong; Santosh, M.; Li, Qing; Gu, Yue; Lü, Wen-Jie; Zhang, Hua-Feng; Shen, Jun-Feng; Zhao, Guo-Chun

    2016-11-01

    Jiaodong peninsula, located at the southeastern margin of the North China Craton, is well known for its rich endowment of super-large gold deposits. This region is also characterized by hundreds of intermediate - mafic dykes that cluster into several dyke swarms. In this study, we present zircon U-Pb ages which show that the timing of dyke emplacement as ca. 120 Ma, which followed the crystallization of the (quartz-) diorite porphyry at ca. 130 Ma. These ages coincide with the peak ages reported for magmatism and metallogeny in the central North China Craton. The various ages (2450-2570 and 154 Ma) from the inherited zircon crystals in these rocks suggest that substantial lower to middle crustal basement rocks and Jurassic granitoids were involved during dyke emplacement. The dyke swarms, varying between alkaline and subalkaline, are compositionally low-Si low-Ti lamprophyre and low-Si high-Ti dolerite porphyry in the western of the Jiaodong peninsula, whereas those in the eastern part are composed of both high-Si low-Ti and low-Si high-Ti lamprophyres. These features imply multiple sources for the dykes from convective asthenospheric mantle to ancient enriched lithospheric mantle with magma generation at different depths involving mixture of slab-derived hydrous fluids. The source magmas of the dykes were hydrous and enriched in volatiles as well as ore components, and their evolution occurred under high oxygen fugacity conditions. The relatively rapid emplacement and cooling of the dyke systems enabled the migration of fluids into ore-controlling faults or fractures. We envisage that the dyke swarms played an important role in generating the world-class gold mineralization of Jiaodong.

  12. Seventeenth century organic agriculture in China: II. Energy flows through an agroecosystem in Jiaxing Region

    SciTech Connect

    Dazhong, W.; Pimentel, D.

    1986-03-01

    The energy flows in a seventeenth century agroecosystem in Jiaxing Region of eastern China were analyzed on the basis of historical data. The agroecosystem included cropping, mulberry-silkworm livestock, and fishing systems. In terms of energy, the agroecosystem was sustainable. Human labor provided all the power with inputs of about 3700 hr per hectare of farmland. Most or 70% of the labor was expended in the cropping system. Human and animal manure provided most of the nutrients for crop and mulberry production. About two-thirds of the total manure was used in crop production and one-third in the mulberry plantations. The only fossil energy input was a few hand tools. Approximately 55% of the grain was consumed directly by local residents, about one-third of the grain was used to make an alcohol drink and produce distillers' grains, which was fed to pigs, and only 2% of the grains were exported outside the agroecosystem. About two-thirds of the harvested crop residues were used as household fuel, while the remainder was returned to the field as an organic fertilizer. Pork accounted for 85% and silk cocoons 14% of the total animal products produced. Even though the agroecosystem was generally sustainable in terms of energy, the major environmental problem was that two-thirds of the harvested crop residues were used for household fuel. This reduced nutrient cycling in the system. Insufficient land was available to produce fuelwood; thus, crop residues were the primary source of fuel for the people.

  13. New Insights into the Respiratory Chain of Plant Mitochondria. Supercomplexes and a Unique Composition of Complex II1

    PubMed Central

    Eubel, Holger; Jänsch, Lothar; Braun, Hans-Peter

    2003-01-01

    A project to systematically investigate respiratory supercomplexes in plant mitochondria was initiated. Mitochondrial fractions from Arabidopsis, potato (Solanum tuberosum), bean (Phaseolus vulgaris), and barley (Hordeum vulgare) were carefully treated with various concentrations of the nonionic detergents dodecylmaltoside, Triton X-100, or digitonin, and proteins were subsequently separated by (a) Blue-native polyacrylamide gel electrophoresis (PAGE), (b) two-dimensional Blue-native/sodium dodecyl sulfate-PAGE, and (c) two-dimensional Blue-native/Blue-native PAGE. Three high molecular mass complexes of 1,100, 1,500, and 3,000 kD are visible on one-dimensional Blue native gels, which were identified by separations on second gel dimensions and protein analyses by mass spectrometry. The 1,100-kD complex represents dimeric ATP synthase and is only stable under very low concentrations of detergents. In contrast, the 1,500-kD complex is stable at medium and even high concentrations of detergents and includes the complexes I and III2. Depending on the investigated organism, 50% to 90% of complex I forms part of this supercomplex if solubilized with digitonin. The 3,000-kD complex, which also includes the complexes I and III, is of low abundance and most likely has a III4I2 structure. The complexes IV, II, and the alternative oxidase were not part of supercomplexes under all conditions applied. Digitonin proved to be the ideal detergent for supercomplex stabilization and also allows optimal visualization of the complexes II and IV on Blue-native gels. Complex II unexpectedly was found to be composed of seven subunits, and complex IV is present in two different forms on the Blue-native gels, the larger of which comprises additional subunits including a 32-kD protein resembling COX VIb from other organisms. We speculate that supercomplex formation between the complexes I and III limits access of alternative oxidase to its substrate ubiquinol and possibly regulates

  14. China.

    PubMed

    1980-05-01

    China's census, scheduled for July 1, 1981, will be preceded by a pilot census at the end of the next month. According to Mr. Y.C. Yu, Statistician in the Demographic and Social Statistics Branch of the UN, the pretest will be held in Wu Xi, a resort area of about 1.6 million persons about a 2-hour train ride west of Shanghai. Mr. Yu and Mr. Varon Kannisto will be UN observers of the pilot census. The method of enumeration will be similar to that used in the 1953 and 1964 censuses, said Mr. Yu. Each head of household will report to an enumeration station to provide information on the characteristics of household members. The questionnaire will contain about 13 items, which will be asked of 100% of the population. The 5 million enumerators will be teachers, accountants, and others, generally residents of the local area in which they will act as enumerators. Census data will be processed by computers in each of the 29 provinces and autonomous regions. The UNFPA is providing computers, data entry and ancillary equipment, software and supplies, advisory services, and training in census methods and data processing. The computers supplied by IBM will be the 4300 series; a model 4341 will be installed at the State Statistical Bureau in Beijing and 15 model 4331s will go to individual provinces. Results of earlier censuses were processed manually and with the abacus. UNFPA also plans to provide support for the analysis of census data and for their dissemination to appropriate organizations and departments in China.

  15. New insight into the structural, electrochemical and biological aspects of macroacyclic Cu(II) complexes derived from S-substituted dithiocarbazate schiff bases.

    PubMed

    Low, May Lee; Maigre, Laure; Tahir, Mohamed Ibrahim M; Tiekink, Edward R T; Dorlet, Pierre; Guillot, Régis; Ravoof, Thahira Begum; Rosli, Rozita; Pagès, Jean-Marie; Policar, Clotilde; Delsuc, Nicolas; Crouse, Karen A

    2016-09-14

    Copper (II) complexes synthesized from the products of condensation of S-methyl- and S-benzyldithiocarbazate with 2,5-hexanedione (SMHDH2 and SBHDH2 respectively) have been characterized using various physicochemical (elemental analysis, molar conductivity, magnetic susceptibility) and spectroscopic (infrared, electronic) methods. The structures of SMHDH2, its copper (II) complex, CuSMHD, and the related CuSBHD complex as well as a pyrrole byproduct, SBPY, have been determined by single crystal X-ray diffraction. In order to provide more insight into the behaviour of the complexes in solution, electron paramagnetic resonance (EPR) and electrochemical experiments were performed. Antibacterial activity and cytotoxicity were evaluated. The compounds, dissolved in 0.5% and 5% DMSO, showed a wide range of antibacterial activity against 10 strains of Gram-positive and Gram-negative bacteria. Investigations of the effects of efflux pumps and membrane penetration on antibacterial activity are reported herein. Antiproliferation activity was observed to be enhanced by complexation with copper. Preliminary screening showed Cu complexes are strongly active against human breast adenocarcinoma cancer cell lines MDA-MB-231 and MCF-7.

  16. Insight into solvent nature on coordination polymerization: Crystal structures of cadmium(II) chloride containing diallylbis(pyridin-4-yl)silane

    NASA Astrophysics Data System (ADS)

    Ryu, Minjoo; Lee, Young-A.; Jung, Ok-Sang

    2017-09-01

    A close insight into a systematic solvent-template effect on self-assembly of cadmium(II) chloride with new diallylbis(pyridin-4-yl)silane ligand (L) has been achieved. Each reaction gives rise to the 1: 2 composition of Cd(II): L, but shows significant solvent template effects on the formation of topology. The reaction in MeOH and in MeCN yields 1D loop chain, [CdCl2L2]·4MeOH and [CdCl2L2]·2MeCN, respectively, containing the solvate molecules whereas the same treatment in the relatively bulky solvents such as EtOH, n-PrOH, and i-PrOH yields interpenetrated 2D sheet, [CdCl2L2]. Their packing structures are also strongly depending on the nature of each solvent. Thus, construction and packing of each structure are determined by solvent templates rather than synthetic methodology. Solvate MeOH molecules of [CdCl2L2]·4MeOH crystals in MeCN media are perfectly exchanged to MeCN molecules and the solvate MeCN molecules of [CdCl2L2]·2MeCN crystals in MeOH media are exchanged into MeOH molecules as solvate, indicating that the solvate molecules do not interact significantly with the skeletal structures.

  17. Interaction of Iron II Complexes with B-DNA. Insights from Molecular Modeling, Spectroscopy and Cellular Biology.

    NASA Astrophysics Data System (ADS)

    Gattuso, Hugo; Duchanois, Thibaut; Besancenot, Vanessa; Barbieux, Claire; Assfeld, Xavier; Becuwe, Philippe; Gros, Philippe; Grandemange, Stephanie; Monari, Antonio

    2015-12-01

    We report the characterization of the interaction between B-DNA and three terpyridin iron II complexes. Relatively long time-scale molecular dynamics is used in order to characterize the stable interaction modes. By means of molecular modeling and UV-vis spectroscopy, we prove that they may lead to stable interactions with the DNA duplex. Furthermore, the presence of larger π-conjugated moieties also leads to the appearance of intercalation binding mode. Non-covalent stabilizing interactions between the iron complexes and the DNA are also characterized and evidenced by the analysis of the gradient of the electronic density. Finally, the structural deformations induced on the DNA in the different binding modes are also evidenced. The synthesis and chemical characterization of the three complexes is reported, as well as their absorption spectra in presence of DNA duplexes to prove the interaction with DNA. Finally, their effects on human cell cultures have also been evidenced to further enlighten their biological effects.

  18. Introduction of a fluorescent probe to amyloid-β to reveal kinetic insights into its interactions with copper(II).

    PubMed

    Branch, Thomas; Girvan, Paul; Barahona, Mauricio; Ying, Liming

    2015-01-19

    The kinetics of the interactions between amyloid-β (Aβ) and metal ions are crucial to understanding the physiological and pathological roles of Aβ in the normal brain and in Alzheimer's disease. Using the quenching of a fluorescent probe by Cu(2+), the mechanism of Aβ/Cu(2+) interactions in physiologically relevant conditions has been elucidated. Cu(2+) binds to Aβ at a near diffusion-limited rate, initially forming component I. The switching between component I and II occurs on the second timescale, with a significant energy barrier. Component I is much more reactive towards Cu(2+) ligands and likely responsible for initial Aβ dimer formation. Clioquinol (CQ) is shown to sequester Cu(2+) more effectively than other tested ligands. These findings have implications for the potential roles of Aβ in regulating neurotransmission, and for the screening of small molecules targeting Aβ-metal interactions.

  19. Experimental Study of Porosity Changes in Shale Caprocks Exposed to Carbon Dioxide-Saturated Brine II: Insights from Aqueous Geochemistry

    DOE PAGES

    Miller, Quin R. S.; Wang, Xiuyu; Kaszuba, John P.; ...

    2016-07-18

    Laboratory experiments evaluated two shale caprock formations, the Gothic Shale and Marine Tuscaloosa Formation, at conditions relevant to carbon dioxide (CO2) sequestration. Both rocks were exposed to CO2-saturated brines at 160°C and 15 MPa for ~45 days. Baseline experiments for both rocks were pressurized with argon to 15 MPa for ~35 days. Varying concentrations of iron, aqueous silica, sulfate, and initial pH decreases coincide with enhanced carbonate and silicate dissolution due to reaction between CO2-saturated brine and shale. Saturation indices were calculated and activity diagrams were constructed to gain insights into sulfate, silicate, and carbonate mineral stabilities. We found thatmore » upon exposure to CO2-saturated brines, the Marine Tuscaloosa Formation appeared to be more reactive than the Gothic Shale. Evolution of aqueous geochemistry in the experiments is consistent with mineral precipitation and dissolution reactions that affect porosity. Finally, this study highlights the importance of tracking fluid chemistry to clarify downhole physicochemical responses to CO2 injection and subsequent changes in sealing capacity in CO2 storage and utilization projects.« less

  20. Insights into large-scale cell-culture reactors: II. Gas-phase mixing and CO₂ stripping.

    PubMed

    Sieblist, Christian; Hägeholz, Oliver; Aehle, Mathias; Jenzsch, Marco; Pohlscheidt, Michael; Lübbert, Andreas

    2011-12-01

    Most discussions about stirred tank bioreactors for cell cultures focus on liquid-phase motions and neglect the importance of the gas phase for mixing, power input and especially CO(2) stripping. Particularly in large production reactors, CO(2) removal from the culture is known to be a major problem. Here, we show that stripping is mainly affected by the change of the gas composition during the movement of the gas phase through the bioreactor from the sparger system towards the headspace. A mathematical model for CO(2)-stripping and O(2)-mass transfer is presented taking gas-residence times into account. The gas phase is not moving through the reactor in form of a plug flow as often assumed. The model is validated by measurement data. Further measurement results are presented that show how the gas is partly recirculated by the impellers, thus increasing the gas-residence time. The gas-residence times can be measured easily with stimulus-response techniques. The results offer further insights on the gas-residence time distributions in stirred tank reactors. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Experimental Study of Porosity Changes in Shale Caprocks Exposed to Carbon Dioxide-Saturated Brine II: Insights from Aqueous Geochemistry

    SciTech Connect

    Miller, Quin R. S.; Wang, Xiuyu; Kaszuba, John P.; Mouzakis, Katherine M.; Navarre-Sitchler, Alexis K.; Alvarado, Vladimir; McCray, John E.; Rother, Gernot; Bañuelos, José Leobardo; Heath, Jason E.

    2016-07-18

    Laboratory experiments evaluated two shale caprock formations, the Gothic Shale and Marine Tuscaloosa Formation, at conditions relevant to carbon dioxide (CO2) sequestration. Both rocks were exposed to CO2-saturated brines at 160°C and 15 MPa for ~45 days. Baseline experiments for both rocks were pressurized with argon to 15 MPa for ~35 days. Varying concentrations of iron, aqueous silica, sulfate, and initial pH decreases coincide with enhanced carbonate and silicate dissolution due to reaction between CO2-saturated brine and shale. Saturation indices were calculated and activity diagrams were constructed to gain insights into sulfate, silicate, and carbonate mineral stabilities. We found that upon exposure to CO2-saturated brines, the Marine Tuscaloosa Formation appeared to be more reactive than the Gothic Shale. Evolution of aqueous geochemistry in the experiments is consistent with mineral precipitation and dissolution reactions that affect porosity. Finally, this study highlights the importance of tracking fluid chemistry to clarify downhole physicochemical responses to CO2 injection and subsequent changes in sealing capacity in CO2 storage and utilization projects.

  2. Experimental Study of Porosity Changes in Shale Caprocks Exposed to Carbon Dioxide-Saturated Brine II: Insights from Aqueous Geochemistry

    SciTech Connect

    Miller, Quin R. S.; Wang, Xiuyu; Kaszuba, John P.; Mouzakis, Katherine M.; Navarre-Sitchler, Alexis K.; Alvarado, Vladimir; McCray, John E.; Rother, Gernot; Bañuelos, José Leobardo; Heath, Jason E.

    2016-07-18

    Laboratory experiments evaluated two shale caprock formations, the Gothic Shale and Marine Tuscaloosa Formation, at conditions relevant to carbon dioxide (CO2) sequestration. Both rocks were exposed to CO2-saturated brines at 160°C and 15 MPa for ~45 days. Baseline experiments for both rocks were pressurized with argon to 15 MPa for ~35 days. Varying concentrations of iron, aqueous silica, sulfate, and initial pH decreases coincide with enhanced carbonate and silicate dissolution due to reaction between CO2-saturated brine and shale. Saturation indices were calculated and activity diagrams were constructed to gain insights into sulfate, silicate, and carbonate mineral stabilities. We found that upon exposure to CO2-saturated brines, the Marine Tuscaloosa Formation appeared to be more reactive than the Gothic Shale. Evolution of aqueous geochemistry in the experiments is consistent with mineral precipitation and dissolution reactions that affect porosity. Finally, this study highlights the importance of tracking fluid chemistry to clarify downhole physicochemical responses to CO2 injection and subsequent changes in sealing capacity in CO2 storage and utilization projects.

  3. Rock Burst Intensity Classification Based on the Radiated Energy with Damage Intensity at Jinping II Hydropower Station, China

    NASA Astrophysics Data System (ADS)

    Chen, Bing-Rui; Feng, Xia-Ting; Li, Qing-Peng; Luo, Ru-Zhou; Li, Shaojun

    2015-01-01

    Based on the radiated energy of 133 rock bursts monitored by a microseismic technique at the Jinping II hydropower station, in Sichuan province, China, we analyzed the advantages and disadvantages of qualitative classification methods for the rock burst intensity. Then, we investigated the characteristics, magnitude, and laws of the radiated energy, as well as the relationship between the rock burst radiated energy and intensity. Then, we selected the energy as an evaluation index for the rock burst intensity classification, and proposed a new rock burst intensity quantitative classification method, which utilized the hierarchical clustering analysis technique with the complete-linkage method. Next, we created a new set of criteria for the quantitative classification of the rock burst intensity based on radiated energy and surrounding rock damage severity. The new criteria classified the rock burst intensity into five levels: extremely intense, intense, moderate, weak, and none, and the common logarithms of the radiated energy of each level were >7 lg( E/J), >4 lg( E/J) and <7 lg( E/J), >2 lg( E/J) and <4 lg( E/J), >1 lg( E/J) and <2 lg( E/J), and <1 lg( E/J), respectively. Finally, we investigated the factors influencing the classification, and verified its feasibility and applicability via several practical rock burst examples.

  4. Water and heat transport in hilly red soil of southern China: II. Modeling and simulation.

    PubMed

    Lu, Jun; Huang, Zhi-Zhen; Han, Xiao-Fei

    2005-05-01

    Simulation models of heat and water transport have not been rigorously tested for the red soils of southern China. Based on the theory of nonisothermal water-heat coupled transfer, a simulation model, programmed in Visual Basic 6.0, was developed to predict the coupled transfer of water and heat in hilly red soil. A series of soil column experiments for soil water and heat transfer, including soil columns with closed and evaporating top end, were used to test the simulation model. Results showed that in the closed columns, the temporal and spatial distribution of moisture and heat could be very well predicted by the model, while in the evaporating columns, the simulated soil water contents were somewhat different from the observed ones. In the heat flow equation from Taylor and Lary (1964), the effects of soil water evaporation on the heat flow is not involved, which may be the main reason for the differences between simulated and observed results. The predicted temperatures were not in agreement with the observed one with thermal conductivities calculated by de Vries and Wierenga equations, so that it is suggested that K(h), soil heat conductivity, be multiplied by 8.0 for the first 6.5 h and by 1.2 later on. Sensitivity analysis of soil water and heat coefficients showed that the saturated hydraulic conductivity, K(S), and the water diffusivity, D(theta), had great effects on soil water transport; the variation of soil porosity led to the difference of soil thermal properties, and accordingly changed temperature redistribution, which would affect water redistribution.

  5. A last glacial and deglacial pollen record from the northern South China Sea: New insight into coastal-shelf paleoenvironment

    NASA Astrophysics Data System (ADS)

    Yu, Shaohua; Zheng, Zhuo; Chen, Fang; Jing, Xia; Kershaw, Peter; Moss, Patrick; Peng, Xuechao; Zhang, Xin; Chen, Chixin; Zhou, Yang; Huang, Kangyou; Gan, Huayang

    2017-02-01

    This study presents a marine palynological record of the Asian summer monsoon and sea level change in the Last Glacial Maximum (LGM) and the deglacial period in the northern South China Sea (SCS). A fossil core STD 235 (855 cm in length) and 273 surface sediment samples from the northern SCS were pollen analysed to reconstruct the paleoenvironment of the continental shelf during the last glacial period. Results from fossil pollen show that the main pollen source region fundamentally changed from the LGM to the deglacial period as sea level rapidly rose. The modern marine surface samples show that pollen concentrations in the estuary of the Pearl River are extremely high, and modern pollen assemblages are in good agreement with the regional vegetation. However, wind transport becomes more important in the deeper ocean as the percentages of Pinus, a taxon with very high pollen production and dispersal capacity, is highest in these sediments, which otherwise have very low pollen concentrations. The concentration of total pollen between surface and fossil pollen samples is compared in order to determine the possible vegetation sources areas for the marine core. Pollen concentration as high as >100 grains/g at the LGM suggested that the paleo-shoreline was located within 80 km of the core. Consequently, pollen would mostly have derived from the exposed continental shelf in the northern SCS. By contrast, pollen concentrations were very low due to a much greater transport distance (318 km at present, core STD 235) under higher sea levels, and windblown pollen played a more important role because of the limitation of riverine input into the deep ocean during this highstand period. Such alternation of pollen flux and source distance should be repeated during all glacial-interglacial cycles, reflecting closely sea level and climate dynamics. According to fossil pollen assemblages from Core STD 235, we conclude that wetland and/or grassland communities with sparse subtropical

  6. Bismuth mineral inclusions in gold-bearing magnetite from the giant Beiya gold deposit, SW China: insights into mineralization process

    NASA Astrophysics Data System (ADS)

    Zhou, Haoyang; Sun, Xiaoming

    2017-04-01

    Bismuth minerals are commonly found in a wide range of gold deposits and could offer valuable information on the process of gold mineralization. This is because Bi minerals always show immediate association with gold and are sensitive to chemical-physical variations (Afifi et al., 1988). Specifically, native bismuth has a melting point of 271°C and could melt at lower temperatures when gold is added (Okamoto et al,, 1983). It has been verified that Bi melt could efficiently scavenge gold from hydrothermal fluids (Tooth et al., 2008, 2011). The Beiya deposit, situated in the Sanjiang Tethyan tectonic domain in the southwestern China, is one of the largest gold deposits in China 10.4 Moz Au @ 2.47g/t). Located along the contacts between a 36 Ma quartz syenite porphyry and the Triassic limestones, the deposit contains abundant massive Au-bearing magnetite ores, which are considered as a product of skarn mineralization. However, the pivotal processes accounting for the huge accumulation of gold resource at Beiya area are poorly constrained. In the massive magnetite ores, abundant native gold was observed to be present as submicron-scale inclusions hosted by magnetite (Zhou et al., 2017). We also noted that abundant Bi minerals occur within these ores (Zhou et al., 2016), which provide critical clues to reveal the processes of gold mineralization. An assemblage of Bi minerals, composed of native bismuth, maldonite and bismuthinite, is present as tiny inclusions in these Au-bearing magnetite grains. Mineralogical study illustrates the encapsulation of native bismuth and maldonite as melts during magnetite growth, which is also supported by the ore-forming temperatures over 300°C derived from previous fluid inclusions study (He et al., 2016). Our thermodynamic modeling demonstrates that Bi melts scavenged gold from hydrothermal fluids. Subsequently, sulfidation of Bi melts resulted in precipitation of gold, which was captured by growing magnetite. We thus propose that

  7. Insights on organic aerosol aging and the influence of coal combustion at a regional receptor site of central eastern China

    NASA Astrophysics Data System (ADS)

    Hu, W. W.; Hu, M.; Yuan, B.; Jimenez, J. L.; Tang, Q.; Peng, J. F.; Hu, W.; Shao, M.; Wang, M.; Zeng, L. M.; Wu, Y. S.; Gong, Z. H.; Huang, X. F.; He, L. Y.

    2013-10-01

    In order to understand the aging and processing of organic aerosols (OA), an intensive field campaign (Campaign of Air Pollution at Typical Coastal Areas IN Eastern China, CAPTAIN) was conducted March-April at a receptor site (a Changdao island) in central eastern China. Multiple fast aerosol and gas measurement instruments were used during the campaign, including a high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) that was applied to measure mass concentrations and non-refractory chemical components of submicron particles (PM1nr). The average mass concentration of PM1(PM1nr+black carbon) was 47 ± 36 μg m-3 during the campaign and showed distinct variation, depending on back trajectories and their overlap with source regions. Organic aerosol (OA) is the largest component of PM1 (30%), followed by nitrate (28%), sulfate (19%), ammonium (15%), black carbon (6%), and chloride (3%). Four OA components were resolved by positive matrix factorization (PMF) of the high-resolution spectra, including low-volatility oxygenated organic aerosol (LV-OOA), semi-volatile oxygenated OA (SV-OOA), hydrocarbon-like OA (HOA) and a coal combustion OA (CCOA). The mass spectrum of CCOA had high abundance of fragments from polycyclic aromatic hydrocarbons (PAHs) (m/z 128, 152, 178, etc.). The average atomic ratio of oxygen to carbon in OA (O / C) at Changdao was 0.59, which is comparable to other field studies reported at locations downwind of large pollution sources, indicating the oxidized nature of most OA during the campaign. The evolution of OA elemental composition in the van Krevelen diagram (H / C vs. O / C) showed a slope of -0.63; however, the OA influenced by coal combustion exhibits a completely different evolution that appears dominated by physical mixing. The aging of organic aerosols vs. photochemical age was investigated. It was shown that OA / ΔCO, as well as LV-OOA / ΔCO and SV-OOA / ΔCO, positively correlated with photochemical age. LV

  8. Insights on organic aerosol aging and the influence of coal combustion at a regional receptor site of Central Eastern China

    NASA Astrophysics Data System (ADS)

    Hu, W. W.; Hu, M.; Yuan, B.; Jimenez, J. L.; Tang, Q.; Peng, J. F.; Hu, W.; Shao, M.; Wang, M.; Zeng, L. M.; Wu, Y. S.; Gong, Z. H.; Huang, X. F.; He, L. Y.

    2013-04-01

    In order to understand the aging and processing of organic aerosols (OA), an intensive field campaign (Campaign of Air Pollution at Typical Coastal Areas In Eastern China, CAPTAIN) was conducted in March-April at a receptor site (Changdao Island) in Central Eastern China. Multiple fast aerosol and gas measurement instruments were used during the campaign, including a high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was applied to measure mass concentrations and non-refractory chemical components of submicron particles (PM1nr). The average mass concentration of PM1 (PM1nr + black carbon) was 47 ± 36 μg m-3 during the campaign and showed distinct variation depending on back trajectories and their overlap with source regions. Organic aerosol (OA) is the largest component of PM1 (30%), followed by nitrate (28%), sulfate (19%), ammonium (15%), black carbon (6%), and chloride (3%). Four OA components were resolved by Positive Matrix Factorization (PMF) of the high-resolution spectra, including low-volatility oxygenated organic aerosol (LV-OOA), semi-volatile oxygenated OA (SV-OOA), hydrocarbon-like OA (HOA) and a coal combustion OA (CCOA), reported here for the first time. The mass spectrum of CCOA has high abundance of fragments from polycyclic aromatic hydrocarbons (PAHs) (m/z 128, 152, 178 etc.). The average atomic ratio of oxygen to carbon in OA (O/C) at Changdao is 0.59, which is comparable to other field studies reported at locations downwind of large pollution sources, indicating the oxidized nature of most OA during the campaign. The evolution of OA elemental composition in the Van Krevelen diagram (H/C vs. O/C) shows a slope of -0.63, however, the OA influenced by coal combution exhibits a completely different evolution that appears dominated by physical mixing. The aging of organic aerosols vs. with photochemical age was investigated. It is shown that OA/ΔCO, as well as LV-OOA/ΔCO and SV-OOA/ΔCO, positively correlated with

  9. Contribution of Marine Group II Euryarchaeota to cyclopentyl tetraethers in the Pearl River estuary and coastal South China Sea: impact on the TEX86 paleothermometer

    NASA Astrophysics Data System (ADS)

    Wang, J. X.; Zhang, C. L.; Xie, W.; Zhang, Y. G.; Wang, P.

    2015-08-01

    TEX86 (TetraEther indeX of glycerol dialkyl glycerol tetraethers (GDGTs) with 86 carbon atoms) has been widely applied to reconstruct (paleo-) sea surface temperature (SST). While Marine Group I (MG I) Thaumarchaeota have been commonly believed to be the source for GDGTs, Marine Group II (MG II Euryarchaeota) have recently been suggested to contribute significantly to the GDGT pool in the ocean. However, little is known how the MG II Euryarchaeota-derived GDGTs may influence TEX86 in marine sediment record. In this study, we characterize MG II Euryarchaeota-produced GDGTs and assess the likely effect of these tetraether lipids on TEX86. Analyses of core lipid (CL-) and intact polar lipid (IPL-) based GDGTs, 454 sequencing and quantitative polymerase chain reaction (qPCR) targeting MG II Euryarchaeota were performed on suspended particulate matter (SPM) and surface sediments collected along a salinity gradient from the lower Pearl River (river water) and its estuary (mixing water) to the coastal South China Sea (seawater). The results showed that the community composition varied along the salinity gradient with MG II Euryarchaeota as the second dominant group in the mixing water and seawater. qPCR data indicated that the abundance of MG II Euryarchaeota in the mixing water was three to four orders of magnitude higher than the river water and seawater. Significant linear correlations were observed between the gene abundance ratio of MG II Euryarchaeota vs. total archaea and the relative abundance of GDGTs-1, -2, -3, or -4 as well as the ring index based on these compounds, which collectively suggest that MG II Euryarchaeota may actively produce GDGTs in the water column. These results also show strong evidence that MG II Euryarchaeota synthesizing GDGTs with 1-4 cyclopentane moieties may bias TEX86 in the water column and sediments. This study highlights that valid interpretation of TEX86 in sediment record, particularly in coastal oceans, needs to consider the

  10. An exo-β-(1→3)-D-galactanase from Streptomyces sp. provides insights into type II arabinogalactan structure

    PubMed Central

    Ling, Naomi X.-Y.; Lee, Joanne; Ellis, Miriam; Liao, Ming-Long; Mau, Shaio-Lim; Guest, David; Janssen, Peter H.; Kováč, Pavol; Bacic, Antony; Pettolino, Filomena A.

    2012-01-01

    An exo-β-(1→3)-D-galactanase (SGalase1) that specifically cleaves the β-(1→3)-D-galactan backbone of arabinogalactan-proteins (AGPs) was isolated from culture filtrates of a soil Streptomyces sp. Internal peptide sequence information was used to clone and recombinantly express the gene in E. coli. The molecular mass of the isolated enzyme was ~45 kDa, similar to the 48.2 kDa mass predicted from the amino acid sequence. The pI, pH and temperature optima for the enzyme were ~7.45, 3.8 and 48 °C, respectively. The native and recombinant enzymes specifically hydrolysed β-(1→3)-D-galacto-oligo- or poly-saccharides from the upstream (non-reducing) end, typical of an exo-acting enzyme. A second homologous Streptomyces gene (SGalase2) was also cloned and expressed. SGalase2 was similar in size (47.9 kDa) and enzyme activity to SGalase1 but differed in its pH optimum (pH 5). Both SGalase1 and SGalase2 are predicted to belong to the CAZy glycosyl hydrolase family GH 43 based on activity, sequence homology and phylogenetic analysis. The Km and Vmax of the native exo-β-(1→3)-D-galactanase for de-arabinosylated gum arabic (dGA) were 19 mg/ml and 9.7 μmol D-Gal/min/mg protein, respectively. The activity of these enzymes is well suited for the study of type II galactan structures and provides an important tool for the investigation of the biological role of AGPs in plants. De-arabinosylated gum arabic (dGA) was used as a model to investigate the use of these enzymes in defining type II galactan structure. Exhaustive hydrolysis of dGA resulted in a limited number of oligosaccharide products with a trisaccharide of Gal2GlcA1 predominating. PMID:22464224

  11. Analysis of ancient human mitochondrial DNA from the Xiaohe cemetery: insights into prehistoric population movements in the Tarim Basin, China.

    PubMed

    Li, Chunxiang; Ning, Chao; Hagelberg, Erika; Li, Hongjie; Zhao, Yongbin; Li, Wenying; Abuduresule, Idelisi; Zhu, Hong; Zhou, Hui

    2015-07-08

    The Tarim Basin in western China, known for its amazingly well-preserved mummies, has been for thousands of years an important crossroad between the eastern and western parts of Eurasia. Despite its key position in communications and migration, and highly diverse peoples, languages and cultures, its prehistory is poorly understood. To shed light on the origin of the populations of the Tarim Basin, we analysed mitochondrial DNA polymorphisms in human skeletal remains excavated from the Xiaohe cemetery, used by the local community between 4000 and 3500 years before present, and possibly representing some of the earliest settlers. Xiaohe people carried a wide variety of maternal lineages, including West Eurasian lineages H, K, U5, U7, U2e, T, R*, East Eurasian lineages B, C4, C5, D, G2a and Indian lineage M5. Our results indicate that the people of the Tarim Basin had a diverse maternal ancestry, with origins in Europe, central/eastern Siberia and southern/western Asia. These findings, together with information on the cultural context of the Xiaohe cemetery, can be used to test contrasting hypotheses of route of settlement into the Tarim Basin.

  12. The Vicissicaudata revisited - insights from a new aglaspidid arthropod with caudal appendages from the Furongian of China.

    PubMed

    Lerosey-Aubril, Rudy; Zhu, Xuejian; Ortega-Hernández, Javier

    2017-09-11

    Cambrian marine ecosystems were dominated by arthropods, and more specifically artiopods. Aglaspidids represent an atypical group amongst them, not the least because they evolved and rapidly diversified during the late Cambrian, a time interval between the two diversification events of the Early Palaeozoic. Recent phylogenetic analyses have retrieved aglaspidids within the Vicissicaudata, a potentially important, but difficult to define clade of artiopods. Here we describe a new aglaspidid from the Furongian Guole Konservat-Lagerstätte of South China. This taxon displays a pretelsonic segment bearing non-walking appendages, features as-yet known in all vicissicaudatans, but aglaspidids. A new comprehensive phylogenetic analysis provides strong support for the legitimacy of a monophyletic clade Vicissicaudata, and demonstrates the pertinence of new characters to define Aglaspidida. It also motivates important changes to the systematics of the phylum, including the elevation of Artiopoda to the rank of subphylum, and the establishment of a new superclass Vicissicaudata and a new aglaspidid family Tremaglaspididae. Two diversification pulses can be recognized in the early history of artiopods - one in the early Cambrian (trilobitomorphs) and the other in the late Cambrian (vicissicaudatans). The discrepancy between this pattern and that traditionally depicted for marine invertebrates in the Early Palaeozoic is discussed.

  13. Precipitation and Air Pollution at Mountain and Plain Stations in Northern China: Insights Gained from Observations and Modeling

    SciTech Connect

    Guo, Jianping; Deng, Minjun; Fan, Jiwen; Li, Zhanqing; Chen, Qian; Zhai, Panmao; Dai, Zhijian; Li, Xiaowen

    2014-04-27

    We analyzed 40 year data sets of daily average visibility (a proxy for surface aerosol concentration) and hourly precipitation at seven weather stations, including three stations located on the Taihang Mountains, during the summertime in northern China. There was no significant trend in summertime total precipitation at almost all stations. However, light rain decreased, whereas heavy rain increased as visibility decreased over the period studied. The decrease in light rain was seen in both orographic-forced shallow clouds and mesoscale stratiform clouds. The consistent trends in observed changes in visibility, precipitation, and orographic factor appear to be a testimony to the effects of aerosols. The potential impact of large-scale environmental factors, such as precipitable water, convective available potential energy, and vertical wind shear, on precipitation was investigated. No direct links were found. To validate our observational hypothesis about aerosol effects, Weather Research and Forecasting model simulations with spectral-bin microphysics at the cloud-resolving scale were conducted. Model results confirmed the role of aerosol indirect effects in reducing the light rain amount and frequency in the mountainous area for both orographic-forced shallow clouds and mesoscale stratiform clouds and in eliciting a different response in the neighboring plains. The opposite response of light rain to the increase in pollution when there is no terrain included in the model suggests that orography is likely a significant factor contributing to the opposite trends in light rain seen in mountainous and plain areas.

  14. Insights into substrate binding to the oxygen-evolving complex of photosystem II from ammonia inhibition studies.

    PubMed

    Vinyard, David J; Brudvig, Gary W

    2015-01-20

    Water oxidation in Photosystem II occurs at the oxygen-evolving complex (OEC), which cycles through distinct intermediates, S0-S4. The inhibitor ammonia selectively binds to the S2 state at an unresolved site that is not competitive with substrate water. By monitoring the yields of flash-induced oxygen production, we show that ammonia decreases the net efficiency of OEC turnover and slows the decay kinetics of S2 to S1. The temperature dependence of biphasic S2 decay kinetics provides activation energies that do not vary in control and ammonia conditions. We interpret our data in the broader context of previous studies by introducing a kinetic model for both the formation and decay of ammonia-bound S2. The model predicts ammonia binds to S2 rapidly (t1/2 = 1 ms) with a large equilibrium constant. This finding implies that ammonia decreases the reduction potential of S2 by at least 2.7 kcal mol(-1) (>120 mV), which is not consistent with ammonia substitution of a terminal water ligand of Mn(IV). Instead, these data support the proposal that ammonia binds as a bridging ligand between two Mn atoms. Implications for the mechanism of O-O bond formation are discussed.

  15. Structural and Functional insights into the catalytic mechanism of the Type II NADH:quinone oxidoreductase family

    PubMed Central

    Marreiros, Bruno C.; Sena, Filipa V.; Sousa, Filipe M.; Oliveira, A. Sofia F.; Soares, Cláudio M.; Batista, Ana P.; Pereira, Manuela M.

    2017-01-01

    Type II NADH:quinone oxidoreductases (NDH-2s) are membrane proteins involved in respiratory chains. These proteins contribute indirectly to the establishment of the transmembrane difference of electrochemical potential by catalyzing the reduction of quinone by oxidation of NAD(P)H. NDH-2s are widespread enzymes being present in the three domains of life. In this work, we explored the catalytic mechanism of NDH-2 by investigating the common elements of all NDH-2s, based on the rationale that conservation of such elements reflects their structural/functional importance. We observed conserved sequence motifs and structural elements among 1762 NDH-2s. We identified two proton pathways possibly involved in the protonation of the quinone. Our results led us to propose the first catalytic mechanism for NDH-2 family, in which a conserved glutamate residue, E172 (in NDH-2 from Staphylococcus aureus) plays a key role in proton transfer to the quinone pocket. This catalytic mechanism may also be extended to the other members of the two-Dinucleotide Binding Domains Flavoprotein (tDBDF) superfamily, such as sulfide:quinone oxidoreductases. PMID:28181562

  16. Interaction of Iron II Complexes with B-DNA. Insights from Molecular Modeling, Spectroscopy, and Cellular Biology

    PubMed Central

    Gattuso, Hugo; Duchanois, Thibaut; Besancenot, Vanessa; Barbieux, Claire; Assfeld, Xavier; Becuwe, Philippe; Gros, Philippe C.; Grandemange, Stephanie; Monari, Antonio

    2015-01-01

    We report the characterization of the interaction between B-DNA and three terpyridin iron II complexes. Relatively long time-scale molecular dynamics (MD) is used in order to characterize the stable interaction modes. By means of molecular modeling and UV-vis spectroscopy, we prove that they may lead to stable interactions with the DNA duplex. Furthermore, the presence of larger π-conjugated moieties also leads to the appearance of intercalation binding mode. Non-covalent stabilizing interactions between the iron complexes and the DNA are also characterized and evidenced by the analysis of the gradient of the electronic density. Finally, the structural deformations induced on the DNA in the different binding modes are also evidenced. The synthesis and chemical characterization of the three complexes is reported, as well as their absorption spectra in presence of DNA duplexes to prove the interaction with DNA. Finally, their effects on human cell cultures have also been evidenced to further enlighten their biological effects. PMID:26734600

  17. Electron-Transfer-Mediated Uranium Detection Using Quasi-Type II Core-Shell Quantum Dots: Insight into Mechanistic Pathways.

    PubMed

    Singhal, Pallavi; Jha, Sanjay K; Vats, Bal Govind; Ghosh, Hirendra N

    2017-08-22

    Uranium is one of the most toxic and important elements present in the environment, and because of its high toxicity, ultra-trace-level detection is of utmost importance. Many methods were reported earlier for this purpose, but each has its own limitations such as high cost, sophisticated instrumentation, sample processing, and so forth. Herein we have demonstrated an alternate method that is much simpler and can be used for the ultra-trace-level detection of uranium. We have synthesized 3-mercaptopropionic acid (MPA)-capped CdSe/CdS core-shell quantum dots (CSQDs) and used its photoluminescence properties to detect uranium in solution. Steady-state emission studies suggest the luminescence quenching of CSQDs in the presence of uranium. Redox levels of CSQDs and uranium suggests that the electron-transfer process from photoexcited CSQDs to uranium is a thermodynamically viable process, which has subsequently been confirmed by time-resolved studies. A Stern-Volmer plot of CSQDs with uranium suggests that the detection limit of this method is 74.5 ppb. The method has an advantage over other reported methods for being simple and low cost and requiring a small amout of sample processing. To the best of our knowledge, we are reporting for the first time uranium detection using quasi-type II CSQDs and proposing the mechanistic path through luminescence spectroscopy, which in turn helps us to design an efficient detection method.

  18. Structural and Functional insights into the catalytic mechanism of the Type II NADH:quinone oxidoreductase family.

    PubMed

    Marreiros, Bruno C; Sena, Filipa V; Sousa, Filipe M; Oliveira, A Sofia F; Soares, Cláudio M; Batista, Ana P; Pereira, Manuela M

    2017-02-09

    Type II NADH:quinone oxidoreductases (NDH-2s) are membrane proteins involved in respiratory chains. These proteins contribute indirectly to the establishment of the transmembrane difference of electrochemical potential by catalyzing the reduction of quinone by oxidation of NAD(P)H. NDH-2s are widespread enzymes being present in the three domains of life. In this work, we explored the catalytic mechanism of NDH-2 by investigating the common elements of all NDH-2s, based on the rationale that conservation of such elements reflects their structural/functional importance. We observed conserved sequence motifs and structural elements among 1762 NDH-2s. We identified two proton pathways possibly involved in the protonation of the quinone. Our results led us to propose the first catalytic mechanism for NDH-2 family, in which a conserved glutamate residue, E172 (in NDH-2 from Staphylococcus aureus) plays a key role in proton transfer to the quinone pocket. This catalytic mechanism may also be extended to the other members of the two-Dinucleotide Binding Domains Flavoprotein (tDBDF) superfamily, such as sulfide:quinone oxidoreductases.

  19. Thermodynamical and structural insights of orange II adsorption by Mg RAlNO 3 layered double hydroxides

    NASA Astrophysics Data System (ADS)

    Mustapha Bouhent, Mohamed; Derriche, Zoubir; Denoyel, Renaud; Prevot, Vanessa; Forano, Claude

    2011-05-01

    [Mg 1- x Al x(OH) 2][(NO 3) x, nH 2O] Layered Double Hydroxide (LDH) sorbents with variable Mg/Al molar ( R=(1- x)/ x) ratios were investigated for adsorption of azo dye, orange II (OII) at various pH and temperature conditions. Mg 2AlNO 3 displays the highest adsorption capacity with 3.611 mmol of OII per gram of Mg 2AlNO 3 at 40 °C. Adsorption isotherms have been fitted using the Langmuir model and free energy of adsorption (Δ G°), enthalpy (Δ H°) and entropy (Δ S°) were calculated. The experimental values for Δ G° in temperature range between 10 and 40 °C were found to be negative indicating that a spontaneous process occurred. Positive calculated enthalpy values, characteristic of an endothermic process were found. Characterization of solids (PXRD, FTIR, UV-vis, TGA/DTA, adsorption isotherm BET analysis, SEM and Zetametry) before and after adsorption showed that adsorption proceeds in two steps. First, adsorption occurs at the LDH surface, followed by intercalation via anion exchange.

  20. Patterns of taxonomic, phylogenetic diversity during a long-term succession of forest on the Loess Plateau, China: insights into assembly process.

    PubMed

    Chai, Yongfu; Yue, Ming; Liu, Xiao; Guo, Yaoxin; Wang, Mao; Xu, Jinshi; Zhang, Chenguang; Chen, Yu; Zhang, Lixia; Zhang, Ruichang

    2016-06-08

    Quantifying the drivers underlying the distribution of biodiversity during succession is a critical issue in ecology and conservation, and also can provide insights into the mechanisms of community assembly. Ninety plots were established in the Loess Plateau region of northern Shaanxi in China. The taxonomic and phylogenetic (alpha and beta) diversity were quantified within six succession stages. Null models were used to test whether phylogenetic distance observed differed from random expectations. Taxonomic beta diversity did not show a regular pattern, while phylogenetic beta diversity decreased throughout succession. The shrub stage occurred as a transition from phylogenetic overdispersion to clustering either for NRI (Net Relatedness Index) or betaNRI. The betaNTI (Nearest Taxon Index) values for early stages were on average phylogenetically random, but for the betaNRI analyses, these stages were phylogenetically overdispersed. Assembly of woody plants differed from that of herbaceous plants during late community succession. We suggest that deterministic and stochastic processes respectively play a role in different aspects of community phylogenetic structure for early succession stage, and that community composition of late succession stage is governed by a deterministic process. In conclusion, the long-lasting evolutionary imprints on the present-day composition of communities arrayed along the succession gradient.

  1. Patterns of taxonomic, phylogenetic diversity during a long-term succession of forest on the Loess Plateau, China: insights into assembly process

    PubMed Central

    Chai, Yongfu; Yue, Ming; Liu, Xiao; Guo, Yaoxin; Wang, Mao; Xu, Jinshi; Zhang, Chenguang; Chen, Yu; Zhang, Lixia; Zhang, Ruichang

    2016-01-01

    Quantifying the drivers underlying the distribution of biodiversity during succession is a critical issue in ecology and conservation, and also can provide insights into the mechanisms of community assembly. Ninety plots were established in the Loess Plateau region of northern Shaanxi in China. The taxonomic and phylogenetic (alpha and beta) diversity were quantified within six succession stages. Null models were used to test whether phylogenetic distance observed differed from random expectations. Taxonomic beta diversity did not show a regular pattern, while phylogenetic beta diversity decreased throughout succession. The shrub stage occurred as a transition from phylogenetic overdispersion to clustering either for NRI (Net Relatedness Index) or betaNRI. The betaNTI (Nearest Taxon Index) values for early stages were on average phylogenetically random, but for the betaNRI analyses, these stages were phylogenetically overdispersed. Assembly of woody plants differed from that of herbaceous plants during late community succession. We suggest that deterministic and stochastic processes respectively play a role in different aspects of community phylogenetic structure for early succession stage, and that community composition of late succession stage is governed by a deterministic process. In conclusion, the long-lasting evolutionary imprints on the present-day composition of communities arrayed along the succession gradient. PMID:27272407

  2. New insights into how increases in fertility improve the growth of rice at the seedling stage in red soil regions of subtropical China.

    PubMed

    Li, Yilin; Shi, Weiming; Wang, Xingxiang

    2014-01-01

    The differences in rhizosphere nitrification activities between high- and low- fertility soils appear to be related to differences in dissolved oxygen concentrations in the soil, implying a relationship to differences in the radial oxygen loss (ROL) of rice roots in these soils. A miniaturised Clark-type oxygen microelectrode system was used to determine rice root ROL and the rhizosphere oxygen profile, and rhizosphere nitrification activity was studied using a short-term nitrification activity assay. Rice planting significantly altered the oxygen cycling in the water-soil system due to rice root ROL. Although the oxygen content in control high-fertility soil (without rice plants) was lower than that in control low-fertility soil, high rice root ROL significantly improved the rhizosphere oxygen concentration in the high-fertility soil. High soil fertility improved the rice root growth and root porosity as well as rice root ROL, resulting in enhanced rhizosphere nitrification. High fertility also increased the content of nitrification-induced nitrate in the rhizosphere, resulting in enhanced ammonium uptake and assimilation in the rice. Although high ammonium pools in the high-fertility soil increased rhizosphere nitrification, rice root ROL might also contribute to rhizosphere nitrification improvement. This study provides new insights into the reasons that an increase in soil fertility may enhance the growth of rice. Our results suggest that an amendment of the fertiliser used in nutrient- and nitrification-poor paddy soils in the red soil regions of China may significantly promote rice growth and rice N nutrition.

  3. Groundwater recharge mechanism in an integrated tableland of the Loess Plateau, northern China: insights from environmental tracers

    NASA Astrophysics Data System (ADS)

    Huang, Tianming; Pang, Zhonghe; Liu, Jilai; Ma, Jinzhu; Gates, John

    2017-05-01

    Assessing groundwater recharge characteristics (recharge rate, history, mechanisms (piston and preferential flow)) and groundwater age in arid and semi-arid environments remains a difficult but important research frontier. Such assessments are particularly important when the unsaturated zone (UZ) is thick and the recharge rate is limited. This study combined evaluations of the thick UZ with those of the saturated zone and used multiple tracers, such as Cl, NO3, Br, 2H, 18O, 13C, 3H and 14C, to study groundwater recharge characteristics in an integrated loess tableland in the Loess Plateau, China, where precipitation infiltration is the only recharge source for shallow groundwater. The results indicate that diffuse recharge beneath crops, as the main land use of the study area, is 55-71 mm yr-1 based on the chloride mass balance of soil profiles. The length of time required for annual precipitation to reach the water table is 160-400 yrs. The groundwater is all pre-modern water and paleowater, with corrected 14C age ranging from 136 to 23,412 yrs. Most of the water that eventually becomes recharge originally infiltrated in July-September. The Cl and NO3 contents in the upper UZ are considerably higher than those in the deep UZ and shallow groundwater because of recent human activities. The shallow groundwater has not been in hydraulic equilibrium with present near-surface boundary conditions. The homogeneous material of the UZ and relatively old groundwater age imply that piston flow is the dominant recharge mechanism for the shallow groundwater in the tableland.

  4. Early Paleozoic intracontinental orogeny and post-orogenic extension in the South China Block: Insights from volcanic rocks

    NASA Astrophysics Data System (ADS)

    Zhang, Xi-Song; Xu, Xi-Sheng; Xia, Yan; Liu, Lei

    2017-06-01

    The early Paleozoic orogeny represents the first extensive Phanerozoic tectono-thermal event in the South China Block (SCB). Two distinct orogeny models, subduction-collision orogeny and intracontinental orogeny, have been proposed, and one of the key controversies is the nature and the tectonic implications of the associated early Paleozoic volcanic rocks in the SCB, which have not yet been systematically investigated. Zircon U-Pb dating results show that these volcanic rocks formed at 445-435 Ma, coeval with large-scale intrusive magmatism (446-420 Ma). The felsic volcanic rocks, which include the Mashan and Hekou dacites and rhyolites, show high SiO2, low MgO and low Fe2O3 contents. Whole-rock trace-element and isotopic compositions of the felsic volcanic rocks suggest that they were generated by partial melting of a Paleoproterozoic crustal component. The mafic volcanic rocks are represented by the Chayuanshan basalts, which are characterized by low SiO2, high MgO, Cr and Ni contents, enrichment in LILEs and depletion in HFSEs. The low Nb/La ratios, high Th/Yb ratios and negative whole-rock ɛNd(t) values suggest that the basalts were derived from partial melting of a metasomatized subcontinental lithospheric mantle (SCLM). The ;subduction signature; (calc-alkaline affinity, enriched LILEs and depleted HFSEs) of the Chayuanshan basalts was supposed to be inherited from the source and it didn't reflect their generation in a subduction-related arc setting. Asthenospheric mantle upwelling and basaltic magma underplating may have been responsible for the partial melting of the crust and the metasomatized SCLM, which produced the Hekou and Mashan dacites and rhyolites and Chayuanshan basalts, respectively. Activation of the pre-existing suture zones, asthenospheric mantle upwelling and extensive partial melting of the crust caused the intensive magmatism of the SCB in early Paleozoic.

  5. Kinetic effects of sulfur oxidation on catalytic nitrile hydration: nitrile hydratase insights from bioinspired ruthenium(II) complexes.

    PubMed

    Kumar, Davinder; Nguyen, Tho N; Grapperhaus, Craig A

    2014-12-01

    Kinetic investigations inspired by the metalloenzyme nitrile hydratase were performed on a series of ruthenium(II) complexes to determine the effect of sulfur oxidation on catalytic nitrile hydration. The rate of benzonitrile hydration was quantified as a function of catalyst, nitrile, and water concentrations. Precatalysts L(n)RuPPh3 (n = 1-3; L(1) = 4,7-bis(2'-methyl-2'-mercapto-propyl)-1-thia-4,7-diazacyclononane; L(2) = 4-(2'-methyl-2'-sulfinatopropyl)-7-(2'-methyl-2'-mercapto-propyl)-1-thia-4,7-diazacyclononane; L(3) = 4-(2'-methyl-2'-sulfinatopropyl)-7-(2'-methyl-2'-sulfenato-propyl)-1-thia-4,7-diazacyclononane) were activated by substitution of triphenylphosphine with substrate in hot dimethylformamide solution. Rate measurements are consistent with a dynamic equilibrium between inactive aqua (L(n)Ru-OH2) and active nitrile (L(n)Ru-NCR) derivatives with K = 21 ± 1, 9 ± 0.9, and 23 ± 3 for L(1) to L(3), respectively. Subsequent hydration of the L(n)Ru-NCR intermediate yields the amide product with measured hydration rate constants (k's) of 0.37 ± 0.01, 0.82 ± 0.07, and 1.59 ± 0.12 M(-1) h(-1) for L(1) to L(3), respectively. Temperature dependent studies reveal that sulfur oxidation lowers the enthalpic barrier by 27 kJ/mol, but increases the entropic barrier by 65 J/(mol K). Density functional theory (DFT) calculations (B3LYP/LanL2DZ (Ru); 6-31G(d) (all other atoms)) support a nitrile bound catalytic cycle with lowering of the reaction barrier as a consequence of sulfur oxidation through enhanced nitrile binding and attack of the water nucleophile through a highly organized transition state.

  6. Comparative Raman study of four plant metallothionein isoforms: Insights into their Zn(II) clusters and protein conformations.

    PubMed

    Tomas, Mireia; Tinti, Anna; Bofill, Roger; Capdevila, Mercè; Atrian, Silvia; Torreggiani, Armida

    2016-03-01

    Four Metallothioneins (MTs) from soybean (Glycine max) were heterologously synthesized and comparatively analysed by Raman spectroscopy. The participation of protein donor groups (S-thiol and N-imidazol) in Zn(II) chelation, as well as the presence of secondary structure elements was comparatively analysed. Metal clusters with different geometry can be hypothesised for the four GmMTs: a cubane-like or an adamantane-like metal cluster in Zn-GmMT1, and dinuclear Zn-S clusters in Zn-GmMT2, Zn-GmMT3 and Zn-GmMT4. The latter have also a similar average Cys/Zn content, whereas a lower ratio is present in Zn-GmMT1. This is possible thanks to the involvement in metal coordination of a greater number of bridging Cys, as well as of some carboxylate groups. As regards secondary structure elements, a large content of β-turn segments is present in all four Zn-GmMTs, especially for isoforms 1 and 4. β-strands give a contribution to the folding of three GmMTs isoforms, and the highest percentage was found in Zn-GmMT2 (~45%). Conversely, the α-helix content is negligible in all the GmMTs except in Zn-GmMT3, where this peculiar feature coincides with the possible involvement of the two His residues in metal coordination. Conversely, His is predominantly free and present as tautomer I in Zn-GmMT4. In conclusion, this work illustrates the attractive potential of Raman spectroscopy, combined with other techniques, to be a very informative tool for evidencing structural differences among in vivo synthesized metal-MT complexes.

  7. Major histocompatibility complex class II genetic variation in forest musk deer (Moschus berezovskii) in China.

    PubMed

    Yao, Gang; Zhu, Ying; Wan, Qiu-Hong; Fang, Sheng-Guo

    2015-10-01

    The major histocompatibility complex (MHC) plays an important role in the immune system of vertebrates. We used the second exon of four MHC class II genes (DRA, DQA1, DQA2 and DRB3) to assess the overall MHC variation in forest musk deer (Moschus berezovskii). We also compared the MHC variation in captive and wild populations. We observed 22 alleles at four loci (four at DRA, four at DQA1, four at DQA2 and 10 at DRB3), 15 of which were newly identified alleles. Results suggest that forest musk deer maintain relatively high MHC variation, which may result from balancing selection. Moreover, considerable diversity was observed at the DRA locus. We found a high frequency of Mobe-DRA*02, Mobe-DQA1*01 and Mobe-DQA2*05 alleles, which may be important for pathogen resistance. A Ewens-Watterson test showed that the DRB3 locus in the wild population had experienced recent balancing selection. We detected a small divergence at the DRA locus, suggesting the effect of weak positive selection on the DRA gene. Alternatively, this locus may be young and not yet adapted a wide spectrum of alleles for pathogen resistance. The significant heterozygosity deficit observed at the DQA1 and DRB3 loci in the captive population and at all four loci in the wild population may be the result of a population bottleneck. Additionally, MHC genetic diversity was higher in the wild population than in the captive, suggesting that the wild population may have the ability to respond to a wider range of pathogens.

  8. Structure of an Essential Type IV Pilus Biogenesis Protein Provides Insights into Pilus and Type II Secretion Systems

    PubMed Central

    Yamagata, Atsushi; Milgotina, Ekaterina; Scanlon, Karen; Craig, Lisa; Tainer, John A.; Donnenberg, Michael S.

    2012-01-01

    Type IV pili (T4Ps) are long cell surface filaments, essential for microcolony formation, tissue adherence, motility, transformation, and virulence by human pathogens. The enteropathogenic E. colibundle-forming pilus (BFP) is a prototypic T4P assembled and powered by BfpD, a conserved GspE secretion superfamily ATPase held by inner membrane proteins BfpC andBfpE, a GspF-family membrane protein. Although the T4P assembly machinery shares similarity with type II secretion (T2S) systems, the structural biochemistry of the T4P machine has been obscure. Here, we report the crystal structure of the two-domain BfpC cytoplasmic region (N-BfpC), responsible for binding to ATPase BfpD and membrane protein BfpE. The N-BfpC structure reveals a prominent central cleft between two α/β domains. Despite negligible sequence similarity, N-BfpC resembles PilM, a cytoplasmic T4P biogenesis protein.Yet surprisingly, N-BfpC has far greaterstructural similarity to T2S component EpsL, with which it also shares virtually no sequence identity. The C-terminus of the cytoplasmic domain, which leads to the transmembrane segment not present in the crystal structure, exits N-BfpC at a positively-charged surface that most likely interacts with the inner membrane, positioning its central cleft for interactions with other Bfp components.Point mutations in surface-exposed N-BfpC residues predicted to be critical for interactions among BfpC, BfpE and BfpD disrupt pilus biogenesis without precluding interactions with BfpE and BfpD and without affecting BfpD ATPase activity. These results illuminate the relationships between T4P biogenesis and T2S systems,imply that subtle changes in component residue interactions can have profound effects on function and pathogenesis, and suggest that T4P systems may be disrupted by inhibitors that donot preclude component assembly. PMID:22387466

  9. Geochronological, geochemical, and Sr-Nd-Hf isotopic characteristics of Cretaceous monzonitic plutons in western Zhejiang Province, Southeast China: New insights into the petrogenesis of intermediate rocks

    NASA Astrophysics Data System (ADS)

    Liu, Liang; Qiu, Jian-Sheng; Zhao, Jiao-Long; Yang, Ze-Li

    2014-05-01

    We present comprehensive petrological, geochemical, and Sr-Nd-Hf isotopic data for the Matou and Dalai plutons in western Zhejiang Province, Southeast China, with the aim of constraining the petrogenesis of monzonites and to offer new insights into the deep processes of interaction between crustal- and mantle-derived magmas beneath SE China. The Matou pluton comprises quartz monzonite, whereas the Dalai pluton consists of quartz monzodiorite. Zircon U-Pb ages obtained by laser ablation-inductively coupled plasma-mass spectrometry show that both plutons were emplaced at 99-101 Ma. Rocks of both plutons are intermediate to silicic, metaluminous to weakly peraluminous, subalkaline, and K-rich in composition. Samples of the plutons are enriched in large ion lithophile (e.g., Rb, K, and Pb) and light rare earth elements, depleted in high-field strength elements (e.g., Nb, Ta, and Ti), and have small negative or no Eu anomalies. In addition, the rocks have high Mg# values (up to 53.9), high zircon ɛHf(t) values (up to - 1.4), and low Nb/U and Ta/U ratios. Geochemical evidence suggests that both depleted asthenospheric and metasomatically enriched mantle components were involved in the formation of these monzonitic rocks. The presence of inherited zircons with Palaeoproterozoic ages and zircons with unusually low ɛHf(t) values (- 12.9) in the Matou quartz monzonites indicates that ancient crustal materials were also involved in their petrogenesis. In combination with the presence of abundant mafic microgranular enclaves (MMEs) with spheroidal to ellipsoidal-ovoidal shapes and xenocrysts within the more diffused enclaves, and the results of trace element modelling, we suggest that the Matou quartz monzonites were generated by mixing between mantle-derived mafic magmas and crustally derived silicic magmas. The Dalai pluton is relatively homogeneous and contains fewer MMEs than the Matou pluton. Zircons from the Dalai pluton show no inherited components, indicating that

  10. Geologic and geochemical insights into the formation of the Taiyangshan porphyry copper–molybdenum deposit, Western Qinling Orogenic Belt, China

    USGS Publications Warehouse

    Kun-Feng Qiu,; Taylor, Ryan D.; Yao-Hui Song,; Hao-Cheng Yu,; Kai-Rui Song,; Nan Li,

    2016-01-01

    Taiyangshan is a poorly studied copper–molybdenum deposit located in the Triassic Western Qinling collisional belt of northwest China. The intrusions exposed in the vicinity of the Taiyangshan deposit record episodic magmatism over 20–30 million years. Pre-mineralization quartz diorite porphyries, which host some of the deposit, were emplaced at 226.6 ± 6.2 Ma. Syn-collisional monzonite and quartz monzonite porphyries, which also host mineralization, were emplaced at 218.0 ± 6.1 Ma and 215.0 ± 5.8 Ma, respectively. Mineralization occurred during the transition from a syn-collisional to a post-collisional setting at ca. 208 Ma. A barren post-mineralization granite porphyry marked the end of post-collisional magmatism at 200.7 ± 5.1 Ma. The ore-bearing monzonite and quartz monzonite porphyries have a εHf(t) range from − 2.0 to + 12.5, which is much more variable than that of the slightly older quartz diorite porphyries, with TDM2 of 1.15–1.23 Ga corresponding to the positive εHf(t) values and TDM1 of 0.62–0.90 Ga corresponding to the negative εHf(t) values. Molybdenite in the Taiyangshan deposit with 27.70 to 38.43 ppm Re suggests metal sourced from a mantle–crust mixture or from mafic and ultramafic rocks in the lower crust. The δ34S values obtained for pyrite, chalcopyrite, and molybdenite from the deposit range from + 1.3‰ to + 4.0‰, + 0.2‰ to + 1.1‰, and + 5.3‰ to + 5.9‰, respectively, suggesting a magmatic source for the sulfur. Calculated δ18Ofluid values for magmatic K-feldspar from porphyries (+ 13.3‰), hydrothermal K-feldspar from stockwork veins related to potassic alteration (+ 11.6‰), and hydrothermal sericite from quartz–pyrite veins (+ 8.6 to + 10.6‰) indicate the Taiyangshan deposit formed dominantly from magmatic water. Hydrogen isotope values for hydrothermal sericite ranging from − 85 to − 50‰ may indicate that magma degassing progressively depleted residual liquid in

  11. Taurus II Stage Test Simulations: Using Large-Scale CFD Simulations to Provide Critical Insight into Plume Induced Environments During Design

    NASA Technical Reports Server (NTRS)

    Struzenberg, L. L.; West, J. S.

    2011-01-01

    This paper describes the use of targeted Loci/CHEM CFD simulations to evaluate the effects of a dual-engine first-stage hot-fire test on an evolving integrated launch pad/test article design. This effort was undertaken as a part of the NESC Independent Assessment of the Taurus II Stage Test Series. The underlying conceptual model included development of a series of computational models and simulations to analyze the plume induced environments on the pad, facility structures and test article. A pathfinder simulation was first developed, capable of providing quick-turn around evaluation of plume impingement pressures on the flame deflector. Results from this simulation were available in time to provide data for an ongoing structural assessment of the deflector. The resulting recommendation was available in a timely manner and was incorporated into construction schedule for the new launch stand under construction at Wallops Flight Facility. A series of Reynolds-Averaged Navier-Stokes (RANS) quasi-steady simulations representative of various key elements of the test profile was performed to identify potential concerns with the test configuration and test profile. As required, unsteady Hybrid-RANS/LES simulations were performed, to provide additional insight into critical aspects of the test sequence. Modifications to the test-specific hardware and facility structures thermal protection as well as modifications to the planned hot-fire test profile were implemented based on these simulation results.

  12. Insight into the function of Group I and Group II metabotropic glutamate (mGlu) receptors: behavioural characterization and implications for the treatment of CNS disorders.

    PubMed

    Spooren, W; Ballard, T; Gasparini, F; Amalric, M; Mutel, V; Schreiber, R

    2003-07-01

    Following the molecular cloning in the early 1990s of the metabotropic glutamate receptors (mGlu1-8), research that focused on the physiology, pharmacology and function of these receptors revealed their potential role in CNS disorders. Numerous psychiatric and neurological dis-orders are indeed linked to changes in excitatory processes, in which glutamate plays a key role. In contrast to ligand-gated ion channels [N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoazolepropionic acid (AMPA) and kainate], which are responsible for fast excitatory transmission, mGlu receptors have a more modulatory role, by contributing to fine-tuning of synaptic efficacy, and control of the accuracy and sharpness of the transmission. Given the fact that the mGlu receptors are G-protein coupled, they obviously constitute new 'drugable' targets for the treatment of various CNS disorders. Due to the recent emergence of subtype-specific ligands for Group I and II mGlu receptors, this review will concentrate on the molecular characteristics, brain localization, pharmacology and physiological role of these receptors, in order to provide further insights into their therapeutic potential.

  13. Microbial Diversity, Distribution and Insight into Their Role in S, Fe and N Biogeochemical Cycling in the Hot Springs at Tengchong Geothermal Fields, Southwest China

    NASA Astrophysics Data System (ADS)

    Li, J.; Peng, X.; Zhang, L.

    2014-12-01

    Ten sediment samples collected from one acidic and three alkaline high temperature hot springs at Tengchong terrestrial geothermal field, Southwest China, were examined by the mineralogical, geochemical, and molecular biological techniques. The mineralogical and geochemical analyses suggested that these hot springs contain relative high concentrations of S, Fe and N chemical species. Specifically, the acidic hot spring was rich in Fe2+, SO42- and NH4+, while the alkaline hot springs were high in NO3-, H2S and S2O3-. Analyses of 16S rRNA sequences showed their bacterial communities were dominated by Aquificae, Cyanobacteria, Deinococci-Thermus, Firmicutes, Proteobacteria, and Thermodesulfobacteria, while the archeal clone libraries were dominated by Desulfurococcales, Sulfolobales, and Thermoproteales. Among them, the potential S-, N- and Fe-related oxidizing and reducing prokaryote were presenting as a relative high proportion but with a great difference in diversity and metabolic approaches of each sample. These findings provide some significant implications for the microbial function in element biogeochemical cycles within the Tengchong geothermal environments: i). the distinct differences in abundance and diversity of microbial communities of geothermal sediments were related to in situ different physicochemical conditions; ii). the S-, N- and Fe-related prokaryote would take advantage of the strong chemical disequilibria in the hot springs; iii). in return, their metabolic activities can promote the transformation of S, Fe and N chemical species, thus founded the bases of biogeochemical cycles in the terrestrial geothermal environments.

  14. Leaf evolution in early-diverging ferns: insights from a new fern-like plant from the Late Devonian of China.

    PubMed

    Wang, De-Ming; Xu, Hong-He; Xue, Jin-Zhuang; Wang, Qi; Liu, Le

    2015-06-01

    With the exception of angiosperms, the main euphyllophyte lineages (i.e. ferns sensu lato, progymnosperms and gymnosperms) had evolved laminate leaves by the Late Devonian. The evolution of laminate leaves, however, remains unclear for early-diverging ferns, largely represented by fern-like plants. This study presents a novel fern-like taxon with pinnules, which provides new insights into the early evolution of laminate leaves in early-diverging ferns. Macrofossil specimens were collected from the Upper Devonian (Famennian) Wutong Formation of Anhui and Jiangsu Provinces, South China. A standard degagement technique was employed to uncover compressed plant portions within the rock matrix. A new fern-like taxon, SHOUGANGIA BELLA GEN ET SP NOV: , is described and represents an early-diverging fern with highly derived features. It has a partially creeping stem with adventitious roots only on one side, upright primary and secondary branches arranged in helices, tertiary branches borne alternately or (sub)oppositely, laminate and usually lobed leaves with divergent veins, and complex fertile organs terminating tertiary branches and possessing multiple divisions and numerous terminal sporangia. Shougangia bella provides unequivocal fossil evidence for laminate leaves in early-diverging ferns. It suggests that fern-like plants, along with other euphyllophyte lineages, had independently evolved megaphylls by the Late Devonian, possibly in response to a significant decline in atmospheric CO2 concentration. Among fern-like plants, planate ultimate appendages are homologous with laminate pinnules, and in the evolution of megaphylls, fertile organs tend to become complex. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. New Insights into How Increases in Fertility Improve the Growth of Rice at the Seedling Stage in Red Soil Regions of Subtropical China

    PubMed Central

    Li, Yilin; Shi, Weiming; Wang, Xingxiang

    2014-01-01

    The differences in rhizosphere nitrification activities between high- and low- fertility soils appear to be related to differences in dissolved oxygen concentrations in the soil, implying a relationship to differences in the radial oxygen loss (ROL) of rice roots in these soils. A miniaturised Clark-type oxygen microelectrode system was used to determine rice root ROL and the rhizosphere oxygen profile, and rhizosphere nitrification activity was studied using a short-term nitrification activity assay. Rice planting significantly altered the oxygen cycling in the water-soil system due to rice root ROL. Although the oxygen content in control high-fertility soil (without rice plants) was lower than that in control low-fertility soil, high rice root ROL significantly improved the rhizosphere oxygen concentration in the high-fertility soil. High soil fertility improved the rice root growth and root porosity as well as rice root ROL, resulting in enhanced rhizosphere nitrification. High fertility also increased the content of nitrification-induced nitrate in the rhizosphere, resulting in enhanced ammonium uptake and assimilation in the rice. Although high ammonium pools in the high-fertility soil increased rhizosphere nitrification, rice root ROL might also contribute to rhizosphere nitrification improvement. This study provides new insights into the reasons that an increase in soil fertility may enhance the growth of rice. Our results suggest that an amendment of the fertiliser used in nutrient- and nitrification-poor paddy soils in the red soil regions of China may significantly promote rice growth and rice N nutrition. PMID:25291182

  16. Leaf evolution in early-diverging ferns: insights from a new fern-like plant from the Late Devonian of China

    PubMed Central

    Wang, De-Ming; Xu, Hong-He; Xue, Jin-Zhuang; Wang, Qi; Liu, Le

    2015-01-01

    Background and Aims With the exception of angiosperms, the main euphyllophyte lineages (i.e. ferns sensu lato, progymnosperms and gymnosperms) had evolved laminate leaves by the Late Devonian. The evolution of laminate leaves, however, remains unclear for early-diverging ferns, largely represented by fern-like plants. This study presents a novel fern-like taxon with pinnules, which provides new insights into the early evolution of laminate leaves in early-diverging ferns. Methods Macrofossil specimens were collected from the Upper Devonian (Famennian) Wutong Formation of Anhui and Jiangsu Provinces, South China. A standard degagement technique was employed to uncover compressed plant portions within the rock matrix. Key Results A new fern-like taxon, Shougangia bella gen. et sp. nov., is described and represents an early-diverging fern with highly derived features. It has a partially creeping stem with adventitious roots only on one side, upright primary and secondary branches arranged in helices, tertiary branches borne alternately or (sub)oppositely, laminate and usually lobed leaves with divergent veins, and complex fertile organs terminating tertiary branches and possessing multiple divisions and numerous terminal sporangia. Conclusions Shougangia bella provides unequivocal fossil evidence for laminate leaves in early-diverging ferns. It suggests that fern-like plants, along with other euphyllophyte lineages, had independently evolved megaphylls by the Late Devonian, possibly in response to a significant decline in atmospheric CO2 concentration. Among fern-like plants, planate ultimate appendages are homologous with laminate pinnules, and in the evolution of megaphylls, fertile organs tend to become complex. PMID:25979918

  17. Changes in monsoon-driven upwelling in the South China Sea over glacial Terminations I and II: a multi-proxy record

    NASA Astrophysics Data System (ADS)

    Sadatzki, Henrik; Sarnthein, Michael; Andersen, Nils

    2016-06-01

    Upwelling intensity in the South China Sea has changed over glacial-interglacial cycles in response to orbital-scale changes in the East Asian Monsoon. Here, we evaluate new multi-proxy records of two sediment cores from the north-eastern South China Sea to uncover millennial-scale changes in winter monsoon-driven upwelling over glacial Terminations I and II. On the basis of U/Th-based speleothem chronology, we compare these changes with sediment records of summer monsoon-driven upwelling east of South Vietnam. Ocean upwelling is traced by reduced (UK'37-based) temperature and increased nutrient and productivity estimates of sea surface waters (δ13C on planktic foraminifera, accumulation rates of alkenones, chlorins, and total organic carbon). Accordingly, strong winter upwelling occurred north-west of Luzon (Philippines) during late Marine Isotope Stage 6.2, Heinrich (HS) and Greenland stadials (GS) HS-11, GS-26, GS-25, HS-1, and the Younger Dryas. During these stadials, summer upwelling decreased off South Vietnam and sea surface salinity reached a maximum suggesting a drop in monsoon rains, concurrent with speleothem records of aridity in China. In harmony with a stadial-to-interstadial see-saw pattern, winter upwelling off Luzon in turn was weak during interstadials, in particular those of glacial Terminations I and II, when summer upwelling culminated east of South Vietnam. Most likely, this upwelling terminated widespread deep-water stratification, coeval with the deglacial rise in atmospheric CO2. Yet, a synchronous maximum in precipitation fostered estuarine overturning circulation in the South China Sea, in particular as long as the Borneo Strait was closed when sea level dropped below -40 m.

  18. Insights on spin delocalization and spin polarization mechanisms in crystals of azido copper(II) dinuclear complexes through the electron spin density Source Function.

    PubMed

    Gatti, Carlo; Macetti, Giovanni; Lo Presti, Leonardo

    2017-08-01

    The Source Function (SF) tool was applied to the analysis of the theoretical spin density in azido Cu(II) dinuclear complexes, where the azido group, acting as a coupler between the Cu(II) cations, is linked to the metal centres either in an end-on or in an end-end fashion. Results for only the former structural arrangement are reported in the present paper. The SF highlights to which extent the magnetic centres contribute to determine the local spin delocalization and polarization at any point in the dimetallic complex and whether an atom or group of atoms of the ligands act in favour or against a given local spin delocalization/polarization. Ball-and-stick atomic SF percentage representations allow for a visualization of the magnetic pathways and of the specific role played by each atom along these paths, at given reference points. Decomposition of SF contributions in terms of a magnetic and of a relaxation component provides further insight. Reconstruction of partial spin densities by means of the Source Function has for the first time been introduced. At variance with the standard SF percentage representations, such reconstructions offer a simultaneous view of the sources originating from specific subsets of contributing atoms, in a selected molecular plane or in the whole space, and are therefore particularly informative. The SF tool is also used to evaluate the accuracy of the analysed spin densities. It is found that those obtained at the unrestricted B3LYP DFT level, relative to those computed at the CASSCF(6,6) level, greatly overestimate spin delocalization to the ligands, but comparatively underestimate magnetic connection (spin transmission) among atoms, along the magnetic pathways. As a consequence of its excessive spin delocalization, the UB3LYP method also overestimates spin polarization mechanisms between the paramagnetic centres and the ligands. Spin delocalization measures derived from the refinement of Polarized Neutron Diffraction data seem in

  19. Synthesis and supramolecular studies of chiral boronated platinum(II) complexes: insights into the molecular recognition of carboranes by β-cyclodextrin.

    PubMed

    Ching, H Y Vincent; Clifford, Sarah; Bhadbhade, Mohan; Clarke, Ronald J; Rendina, Louis M

    2012-11-05

    The synthesis and characterisation of a novel isomeric family of closo-carborane-containing Pt(II) complexes ((R/S)-(1-4)⋅2 NO(3)) are reported. Related complexes (5⋅NO(3) and 6⋅NO(3)) that contain the 7,8-nido-carborane cluster were obtained from the selective deboronation of the 1,2-closo-carborane analogues. The corresponding water-soluble supramolecular 1:1 host-guest β-cyclodextrin (β-CD) adducts ((R/S)-(1-4)⋅β-CD⋅2 NO(3)) were also prepared and fully characterised. HR-ESI-MS experiments confirmed the presence of the host-guest adducts, and 2D-(1) H{(11)B} ROESY NMR studies showed that the boron clusters enter the β-CD from the side of the wider annulus. Isothermal titration calorimetry (ITC) experiments revealed enthalpically driven 1:1 and higher-order supramolecular interactions between β-CD and (R/S)-(1-4)⋅2 NO(3) in aqueous solution. A comparison of the predominate 1:1 binding mode established that the affinity of β-CD for the guest molecule is mainly influenced by the pyridyl ring substitution pattern and chirality of the host, whilst the nature of the closo-carborane isomer also plays some role, with the most favourable structural features for β-CD binding being the presence of the 4-pyridyl ring, 1,12-closo-carborane, and an S configuration. The results reported here represent the first comprehensive calorimetric study of the supramolecular interactions between closo-carborane compounds and β-CD, and it provides fascinating insights into the structural features influencing the thermodynamics of this phenomenon.

  20. Understanding of regional air pollution over China using CMAQ, part II. Process analysis and sensitivity of ozone and particulate matter to precursor emissions

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Huan; Zhang, Yang; Xing, Jia; Zhang, Qiang; Wang, Kai; Streets, David G.; Jang, Carey; Wang, Wen-Xing; Hao, Ji-Ming

    2010-09-01

    Following model evaluation in part I, this part II paper focuses on the process analysis and chemical regime analysis for the formation of ozone (O 3) and particulate matter with aerodynamic diameter less than or equal to 10 μm (PM 10) in China. The process analysis results show that horizontal transport is the main contributor to the accumulation of O 3 in Jan., Apr., and Oct., and gas-phase chemistry and vertical transport contribute to the production and accumulation of O 3 in Jul. Removal pathways of O 3 include vertical and horizontal transport, gas-phase chemistry, and cloud processes, depending on locations and seasons. PM 10 is mainly produced by primary emissions and aerosol processes and removed by horizontal transport. Cloud processes could either decrease or increase PM 10 concentrations, depending on locations and seasons. Among all indicators examined, the ratio of P/PO provides the most robust indicator for O 3 chemistry, indicating a VOC-limited O 3 chemistry over most of the eastern China in Jan., NO x-limited in Jul., and either VOC- or NO x-limited in Apr. and Oct. O 3 chemistry is NO x-limited in most central and western China and VOC-limited in major cities throughout the year. The adjusted gas ratio, AdjGR, indicates that PM formation in the eastern China is most sensitive to the emissions of SO 2 and may be more sensitive to emission reductions in NO x than in NH 3. These results are fairly consistent with the responses of O 3 and PM 2.5 to the reductions of their precursor emissions predicted from sensitivity simulations. A 50% reduction of NO x or AVOC emissions leads to a reduction of O 3 over the eastern China. Unlike the reduction of emissions of SO 2, NO x, and NH 3 that leads to a decrease in PM 10, a 50% reduction of AVOC emissions increases PM 10 levels. Such results indicate the complexity of O 3 and PM chemistry and a need for an integrated, region-specific emission control strategy with seasonal variations to effectively control

  1. Thermodynamical and structural insights of orange II adsorption by Mg{sub R}AlNO{sub 3} layered double hydroxides

    SciTech Connect

    Mustapha Bouhent, Mohamed; Derriche, Zoubir; Denoyel, Renaud; Prevot, Vanessa; Forano, Claude

    2011-05-15

    [Mg{sub 1-x} Al{sub x}(OH){sub 2}][(NO{sub 3}){sub x}, nH{sub 2}O] Layered Double Hydroxide (LDH) sorbents with variable Mg/Al molar (R=(1-x)/x) ratios were investigated for adsorption of azo dye, orange II (OII) at various pH and temperature conditions. Mg{sub 2}AlNO{sub 3} displays the highest adsorption capacity with 3.611 mmol of OII per gram of Mg{sub 2}AlNO{sub 3} at 40 {sup o}C. Adsorption isotherms have been fitted using the Langmuir model and free energy of adsorption ({Delta}G{sup o}), enthalpy ({Delta}H{sup o}) and entropy ({Delta}S{sup o}) were calculated. The experimental values for {Delta}G{sup o} in temperature range between 10 and 40 {sup o}C were found to be negative indicating that a spontaneous process occurred. Positive calculated enthalpy values, characteristic of an endothermic process were found. Characterization of solids (PXRD, FTIR, UV-vis, TGA/DTA, adsorption isotherm BET analysis, SEM and Zetametry) before and after adsorption showed that adsorption proceeds in two steps. First, adsorption occurs at the LDH surface, followed by intercalation via anion exchange. -- Graphical Abstract: Structural and thermodynamical insight of adsorption/Intercalation of OII in Mg{sub R}Al LDH Display Omitted Highlights: {yields} The nitrate containing hydrotalcite-like compounds (Mg{sub R}AlNO{sub 3} LDH) were prepared by the coprecipitation method. {yields} Adsorption of anionic orange dye(OII) is studied on LDHs at different temperatures. {yields} The adsorption process is well described by the Langmuir isotherm model. {yields} Mg{sub 2}AlNO{sub 3} displays the highest adsorption capacity with 3.611 mmol of OII per gram of Mg{sub 2}AlNO{sub 3} at 40 {sup o}C. {yields} Adsorption process does not occur on the surface of the LDH only but an intercalation process is also occurring concomitantly according to the thermodynamical values.

  2. The NMR structure of the II-III-VI three-way junction from the Neurospora VS ribozyme reveals a critical tertiary interaction and provides new insights into the global ribozyme structure.

    PubMed

    Bonneau, Eric; Girard, Nicolas; Lemieux, Sébastien; Legault, Pascale

    2015-09-01

    As part of an effort to structurally characterize the complete Neurospora VS ribozyme, NMR solution structures of several subdomains have been previously determined, including the internal loops of domains I and VI, the I/V kissing-loop interaction and the III-IV-V junction. Here, we expand this work by determining the NMR structure of a 62-nucleotide RNA (J236) that encompasses the VS ribozyme II-III-VI three-way junction and its adjoining stems. In addition, we localize Mg(2+)-binding sites within this structure using Mn(2+)-induced paramagnetic relaxation enhancement. The NMR structure of the J236 RNA displays a family C topology with a compact core stabilized by continuous stacking of stems II and III, a cis WC/WC G•A base pair, two base triples and two Mg(2+) ions. Moreover, it reveals a remote tertiary interaction between the adenine bulges of stems II and VI. Additional NMR studies demonstrate that both this bulge-bulge interaction and Mg(2+) ions are critical for the stable folding of the II-III-VI junction. The NMR structure of the J236 RNA is consistent with biochemical studies on the complete VS ribozyme, but not with biophysical studies performed with a minimal II-III-VI junction that does not contain the II-VI bulge-bulge interaction. Together with previous NMR studies, our findings provide important new insights into the three-dimensional architecture of this unique ribozyme.

  3. Effect of pectin on adsorption of Cu(II) by two variable-charge soils from southern China.

    PubMed

    Wang, Ru-hai; Zhu, Xiao-fang; Qian, Wei; Yu, Yuan-chun; Xu, Ren-kou

    2015-12-01

    The influence of pectin on Cu(II) adsorption by two variable-charge soils (an Oxisol and an Ultisol) was investigated. Pectin increased the adsorption, and the extent of adsorption increased linearly with the dose of pectin, being greater in the Oxisol than that in the Ultisol because the adsorption of pectin by the Oxisol was greater. Both Langmuir and Freundlich equations fitted the adsorption isotherms of Cu(II) for both soils well. The fitting parameters of both equations indicated that pectin increased not only the adsorption capacity of the soils for Cu(II) but also the adsorption strength of Cu(II). The effect of pectin decreased with rising pH in the pH range 3.5-6.0, although the extent of electrostatic adsorption of Cu(II) by both soils was markedly greater over the pH range. Fourier-transformed infrared spectroscopy analysis and zeta potential measurement of soil colloids indicated that adsorption of pectin by the soils made the negative charge on both soils more negative, which was responsible for the increase in the electrostatic adsorption of Cu(II) induced by the addition of pectin. In conclusion, pectin-enhanced adsorption of Cu(II) especially at low pH would be beneficial to the soils as it would decrease the activity and mobility of Cu(II) in acidic variable-charge soils.

  4. A Primary Investigation on Serum CTX-II Changes in Patients Infected with Brucellosis in Qinghai Plateau, China.

    PubMed

    Zhao, Zhi Jun; Li, Qiang; Zhou, Xin; Ma, Li; Xu, Li Qing; Yang, Pei Zhen; Meng, Xian Ya; Yu, Hui Zhen; Xu, Xiao Qing; Cao, Jian Ying

    2016-03-01

    Brucellosis is one of the most widespread zoonotic diseases, with the most frequent complication being osteoarticular changes. The aim of this study was to assess the changes of C-terminal telopeptide of type II collagen (CTX-II) in patients infected with brucellosis. A total of 84 brucellosis patients and 43 volunteers were selected and divided into brucellosis vs. control groups. Serum samples were subjected to serological tests for brucellosis, and CTX-II levels in all samples were measured simultaneously with ELISA. The results showed that serum CTX-II levels in human brucellosis were higher than those of healthy controls, without a statistically significant difference, but serum CTX-II levels in male patients were significantly higher than those of female patients (P<0.05). This finding could indicate the biological changes in the cartilage and bone in human brucellosis.

  5. Comparison of family functioning in families of depressed patients and nonclinical control families in China using the Family Assessment Device and the Family Adaptability and Cohesion Evaluation Scales II.

    PubMed

    Du, Na; Ran, Mao-Sheng; Liang, Su-gai; SiTu, Ming-jing; Huang, Yi; Mansfield, Abigail K; Keitner, Gabor

    2014-02-01

    Family functioning influences the course and long-term outcome for patients with depression. It is important to understand the family functioning of depressed patients from the viewpoint both of patients and their family members. The objective of this study was to explore the association between family functioning and depression in a sample of Chinese families, using the Family Assessment Device (FAD) and the Family Adaptability and Cohesion Evaluation Scales II (FACES II). This study was conducted in a sample of 61 depressed patients and their family members and 61 nonclinical controls in mainland China. It compared the perception of depressed patients and their family members and evaluated agreement between family members. Results indicate that in mainland China, functioning among families with a depressed family member is poorer than that of control families. Depressed patients reported less satisfaction than did their family members. There were significant differences on 4 of the 7 FAD scales among depressed patients and their family members, whereas no discrepancies were found on the FACES II. For the FAD, low agreement between patients and family members was found on all scales except behavioral control. Moderate agreement appeared on all dimensions of FACES II except for ideal cohesion and dissatisfaction with cohesion for the families of depressed patients. Depression is associated with impaired family functioning in families in mainland China. When applying the FAD and FACES II to samples of Chinese families, clinicians should be aware that the FAD may be more sensitive to detecting problems in some areas than the FACES II.

  6. Insight to ternary complexes of co-adsorption of norfloxacin and Cu(II) onto montmorillonite at different pH using EXAFS.

    PubMed

    Pei, Zhi-Guo; Shan, Xiao-Quan; Zhang, Shu-Zhen; Kong, Jing-Jing; Wen, Bei; Zhang, Jing; Zheng, Li-Rong; Xie, Ya-Ning; Janssens, Koen

    2011-02-15

    Co-adsorption of norfloxacin (Nor) and Cu(II) on montmorillonite at pH 4.5, 7.0 and 9.0 was studied by integrated batch adsorption experiments and extended X-ray absorption fine structure (EXAFS) spectroscopy. Under such pH conditions the dominant species of Nor are cation (Nor(+)), zwitterion (Nor(±)), and anion (Nor(-)), respectively. Results indicated that Nor sorption decreased with an increase of solution pH. The presence of Cu(II) slightly suppressed the Nor(+) sorption at pH 4.5, while increased Nor(±) and Nor(-)sorption on montmorillonite at pH 7.0 and 9.0, respectively. In contrast, Nor increased Cu(II) adsorption at pH 4.5, but had little effect on the adsorption of Cu(II) on montmorillonite at pH 7.0 and 9.0. Spectroscopic results showed that, at pH 4.5, Nor(+) was sorbed on montmorillonite by the formation of outer-sphere montmorillonite-Nor-Cu(II) ternary surface complex. At pH 7.0, montmorillonite-Nor-Cu(II) and montmorillonite-Cu(II)-Nor ternary surface complexes co-exist. At pH 9.0, montmorillonite-Cu(II)-Nor ternary surface complex was likely formed, which was different to Cu(II)(Nor)(2) precipitate of the solution. Copyright © 2010 Elsevier B.V. All rights reserved.

  7. [Study on the co-adsorption mechanism of Pb (II) and chlorpyrifos on arid loess in northwestern China].

    PubMed

    Fan, Chun-Hui; Zhang, Ying-Chao; Wang, Jia-Hong

    2013-08-01

    The co-adsorption characteristics of Pb(II) and chlorpyrifos on arid loess were investigated with batch adsorption procedures, and the co-adsorption mechanism was studied with approaches of SEM, FT-IR, XRD and theoretical analysis. The experimental results indicated that the adsorption process of Pb(II) and chlorpyrifos on loess fit better the Langmuir isotherm, the maximum adsorption capacity of q(m) is 12.5 and 0.64 mg x g(-1) for Pb(II) and chlorpyrifos on loess, respectively, and the reaction could be illustrated with pseudo-second order kinetic equation. The SEM micrograph of loess surface varies little after the adsorption process of Pb(II) and chlorpyrifos, and certain wave peaks of FTIR spectra red-shift, disappears or intensity-decrease, with the XRD pattern and theoretical analysis, the adsorption mechanism is described as follows: the adsorption of Pb (II) on arid loess is the chemical-effect of coordination-complexation and Van der Waals force; the physical-adsorption on chlorpyrifos involves the interception function, hydrogen bonds and Van der Waals force, and chemical adsorption effect to some extent. The organic matter in arid loess plays an important role in Pb(II) and chlorpyrifos adsorption.

  8. Insights into Nitrate-Reducing Fe(II) Oxidation Mechanisms through Analysis of Cell-Mineral Associations, Cell Encrustation, and Mineralogy in the Chemolithoautotrophic Enrichment Culture KS.

    PubMed

    Nordhoff, M; Tominski, C; Halama, M; Byrne, J M; Obst, M; Kleindienst, S; Behrens, S; Kappler, A

    2017-07-01

    Most described nitrate-reducing Fe(II)-oxidizing bacteria (NRFeOB) are mixotrophic and depend on organic cosubstrates for growth. Encrustation of cells in Fe(III) minerals has been observed for mixotrophic NRFeOB but not for autotrophic phototrophic and microaerophilic Fe(II) oxidizers. So far, little is known about cell-mineral associations in the few existing autotrophic NRFeOB. Here, we investigate whether the designated autotrophic Fe(II)-oxidizing strain (closely related to Gallionella and Sideroxydans) or the heterotrophic nitrate reducers that are present in the autotrophic nitrate-reducing Fe(II)-oxidizing enrichment culture KS form mineral crusts during Fe(II) oxidation under autotrophic and mixotrophic conditions. In the mixed culture, we found no significant encrustation of any of the cells both during autotrophic oxidation of 8 to 10 mM Fe(II) coupled to nitrate reduction and during cultivation under mixotrophic conditions with 8 to 10 mM Fe(II), 5 mM acetate, and 4 mM nitrate, where higher numbers of heterotrophic nitrate reducers were present. Two pure cultures of heterotrophic nitrate reducers (Nocardioides and Rhodanobacter) isolated from culture KS were analyzed under mixotrophic growth conditions. We found green rust formation, no cell encrustation, and only a few mineral particles on some cell surfaces with 5 mM Fe(II) and some encrustation with 10 mM Fe(II). Our findings suggest that enzymatic, autotrophic Fe(II) oxidation coupled to nitrate reduction forms poorly crystalline Fe(III) oxyhydroxides and proceeds without cellular encrustation while indirect Fe(II) oxidation via heterotrophic nitrate-reduction-derived nitrite can lead to green rust as an intermediate mineral and significant cell encrustation. The extent of encrustation caused by indirect Fe(II) oxidation by reactive nitrogen species depends on Fe(II) concentrations and is probably negligible under environmental conditions in most habitats.IMPORTANCE Most described nitrate

  9. Zinc(II) Binding Site to the Amyloid-β Peptide: Insights from Spectroscopic Studies with a Wide Series of Modified Peptides

    PubMed Central

    2016-01-01

    The Zn(II) ion has been linked to Alzheimer’s disease (AD) due to its ability to modulate the aggregating properties of the amyloid-β (Aβ) peptide, where Aβ aggregation is a central event in the etiology of the disease. Delineating Zn(II) binding properties to Aβ is thus a prerequisite to better grasp its potential role in AD. Because of (i) the flexibility of the Aβ peptide, (ii) the multiplicity of anchoring sites, and (iii) the silent nature of the Zn(II) ion in most classical spectroscopies, this is a difficult task. To overcome these difficulties, we have investigated the impact of peptide alterations (mutations, N-terminal acetylation) on the Zn(Aβ) X-ray absorption spectroscopy fingerprint and on the Zn(II)-induced modifications of the Aβ peptides’ NMR signatures. We propose a tetrahedrally bound Zn(II) ion, in which the coordination sphere is made by two His residues and two carboxylate side chains. Equilibria between equivalent ligands for one Zn(II) binding position have also been observed, the predominant site being made by the side chains of His6, His13 or His14, Glu11, and Asp1 or Glu3 or Asp7, with a slight preference for Asp1. PMID:27665863

  10. Modelling study of boundary-layer ozone over northern China - Part II: Responses to emission reductions during the Beijing Olympics

    NASA Astrophysics Data System (ADS)

    Tang, Guiqian; Zhu, Xiaowan; Xin, Jinyuan; Hu, Bo; Song, Tao; Sun, Yang; Wang, Lili; Wu, Fangkun; Sun, Jie; Cheng, Mengtian; Chao, Na; Li, Xin; Wang, Yuesi

    2017-09-01

    The implementation of emission reduction measures during the Olympics provided a valuable opportunity to study regional photochemical pollution over northern China. In this study, the fifth-generation Pennsylvania State University/National Centre for Atmospheric Research Mesoscale Model and Community Multiscale Air Quality model system was applied to conduct two sets of modelling analyses of the period from July 20 to September 20, 2008, to illustrate the influences of emission reduction measures on regional photochemical pollution over northern China during the Beijing Olympics. The results indicated that the implementation of emission control measures decreased the concentrations of ozone (O3) precursors, namely nitrogen oxide (NOx) and volatile organic compounds (VOCs), throughout the boundary layer. The concentrations of these compounds were reduced by 45% in the central urban area of Beijing at the ground level. Although the average O3 concentration in the central urban area increased by more than 8 ppbv, the total oxidant concentration decreased significantly by more than 5 ppbv. Greater O3 concentrations mainly occurred during periods with weak photochemical reactions. During periods of strong photochemical production, the O3 concentration decreased significantly due to a weakening vertical circulation between the lower and upper boundary layer. Consequently, the number of days when the O3 concentration exceeded 100 ppbv decreased by 25% in Beijing. The emission control measures altered the sensitivity of the regional O3 production. The coordinated control region of NOx and VOCs expanded, and the control region of VOCs decreased in size. The reduction of non-point-source emissions, such as fugitive VOCs and vehicles, was more useful for controlling regional photochemical pollution over northern China.

  11. Testing promoter activity in the trypanosome genome: isolation of a metacyclic-type VSG promoter, and unexpected insights into RNA polymerase II transcription.

    PubMed

    McAndrew, M; Graham, S; Hartmann, C; Clayton, C

    1998-09-01

    In trypanosomes, most genes are arranged in polycistronic transcription units. Individual mRNAs are generated by 5'-trans splicing and 3' polyadenylation. Remarkably, no regulation of RNA polymerase II transcription has been detected although many RNAs are differentially expressed during kinetoplastid life cycles. Demonstration of specific class II promoters is complicated by the difficulty in distinguishing between genuine promoter activity and stimulation of trans splicing. Using vectors that were designed to allow the detection of low promoter activities in a transcriptionally silent chromosomal context, we isolated a novel trypanosome RNA polymerase I promoter. We were however unable to detect class II promoter activity in any tested DNA fragment. We also integrated genes which were preceded by a T3 promoter into the genome of cells expressing bacteriophage T3 polymerase: surprisingly, transcription was alpha-amanitin sensitive. One possible interpretation of these results is that in trypanosomes, RNA polymerase II initiation is favored by genomic accessibility and double-strand melting.

  12. An outbreak of acute respiratory disease caused by a virus associated RNA II gene mutation strain of human adenovirus 7 in China, 2015

    PubMed Central

    Liang, Beibei; Wu, Fuli; Li, Hao; Liu, Hongbo; Sheng, Chunyu; Ma, Qiuxia; Yang, Chaojie; Xie, Jing; Li, Peng; Jia, Leili; Wang, Ligui; Du, Xinying; Qiu, Shaofu; Song, Hongbin

    2017-01-01

    Human adenovirus 7 (HAdV-7) strains are a major cause of acute respiratory disease (ARD) among adults and children, associated with fatal pneumonia. An ARD outbreak caused by HAdV-7 that involved 739 college students was reported in this article. To better understand the underlying cause of this large-scale epidemic, virus strains were isolated from infected patients and sequence variations of the whole genome sequence were detected. Evolutionary trees and alignment results indicated that the major capsid protein genes hexon and fibre were strongly conserved among serotype 7 strains in China at that time. Instead, the HAdV-7 strains presented three thymine deletions in the virus associated RNA (VA RNA) II terminal region. We also found that the mutation might lead to increased mRNA expression of an adjacent gene, L1 52/55K, and thus promoted faster growth. These findings suggest that sequence variation of VA RNA II gene was a potential cause of such a severe HAdV-7 infection and this gene should be a new-emerging factor to be monitored for better understanding of HAdV-7 infection. PMID:28225804

  13. An outbreak of acute respiratory disease caused by a virus associated RNA II gene mutation strain of human adenovirus 7 in China, 2015.

    PubMed

    Yang, Xiaoxia; Wang, Qiongshu; Liang, Beibei; Wu, Fuli; Li, Hao; Liu, Hongbo; Sheng, Chunyu; Ma, Qiuxia; Yang, Chaojie; Xie, Jing; Li, Peng; Jia, Leili; Wang, Ligui; Du, Xinying; Qiu, Shaofu; Song, Hongbin

    2017-01-01

    Human adenovirus 7 (HAdV-7) strains are a major cause of acute respiratory disease (ARD) among adults and children, associated with fatal pneumonia. An ARD outbreak caused by HAdV-7 that involved 739 college students was reported in this article. To better understand the underlying cause of this large-scale epidemic, virus strains were isolated from infected patients and sequence variations of the whole genome sequence were detected. Evolutionary trees and alignment results indicated that the major capsid protein genes hexon and fibre were strongly conserved among serotype 7 strains in China at that time. Instead, the HAdV-7 strains presented three thymine deletions in the virus associated RNA (VA RNA) II terminal region. We also found that the mutation might lead to increased mRNA expression of an adjacent gene, L1 52/55K, and thus promoted faster growth. These findings suggest that sequence variation of VA RNA II gene was a potential cause of such a severe HAdV-7 infection and this gene should be a new-emerging factor to be monitored for better understanding of HAdV-7 infection.

  14. Reaction zone between pre-UHP titanite and host rock: insights into fluid-rock interaction and deformation mechanisms during exhumation of deeply subducted continental crust (Dabie Shan UHP unit, China)

    NASA Astrophysics Data System (ADS)

    Wawrzenitz, N.; Romer, R. L.; Grasemann, B.; Morales, L. F. G.

    2012-04-01

    Exhumed crustal UHP rocks may occur as relict blocks in strongly metasomatized matrix rocks. Due to variations in competence between the mm to km sized blocks and their ductile matrix, the largely undeformed blocks may preserve the pre-subduction and the prograde history, whereas the matrix rocks have been ductilely deformed to high magnitudes and record successive stages of deformation. The reaction zones between blocks and matrix, however, provide insights into the fluid-rock interaction, deformation and the deformation mechanisms active during the exhumation of deeply subducted continental crust in the subduction channel. We investigate a titanite megacryst (3 cm in diameter) in a calc-silicate marble from the UHP unit in the Dabie Shan, China. The core of the titanite megacryst grew prograde during subduction. Its U-Pb system remained closed and yields a maximum age for UHP metamorphism. Sr and Nd isotope compositions in the core demonstrate that the titanite megacryst precipitated from a homogeneous fluid source. During metamorphism in the subduction zone, infiltration of external fluids resulted first in Sr-loss from the marbles and then introduction of Sr with unusually low 87Sr/86S values (Romer et al., 2003), leading to the contrasting 87Sr/86Sr values in the titanite megacryst and the hosting UHP marbles (Wawrzenitz et al., 2006). Related to deformation in the calc-silicate marble matrix, the rim of the titanite megacryst has been replaced during the following dissolution-precipitation reactions: (i) Pseudomorphic replacement of the old titanite megacryst by coupled dissolution-reprecipitation. Fluid migrated into the old grain producing a sharp boundary of the replacement front. (ii) New small titanite grains grew with their long axes parallel to the foliation of the marble matrix, reflecting the activation of dissolution precipitation creep. In the matrix, the foliation is defined by the orientation of the basal planes of phengitic white mica. The new

  15. Role of salt bridge dynamics in inter domain recognition of human IMPDH isoforms: an insight to inhibitor topology for isoform-II.

    PubMed

    Bairagya, Hridoy R; Mukhopadhyay, Bishnu P; Bera, Asim K

    2011-12-01

    Inosine monophosphate dehydrogenase (IMPDH) enzyme involves in the biosynthesis pathway of guanosine nucleotide. Type II isoform of the enzyme is selectively upregulated in neoplastic fast replicating lymphocytes and CML cancer cells. The hIMPDH-II is an excellent target for antileukemic agent. The detailed investigation during MD-Simulation (15 ns) of three different unliganded structures (1B3O, 1JCN and 1JR1) have clearly explored the salt bridge mediated stabilization of inter or intra domain (catalytic domains I(N), I(C) with res. Id. 28-111 and 233-504, whereas two CBS domains C₁, C₂ are 112-171 and 172-232) in IMPDH enzyme which are mostly inaccessible in their X-rays structures. The salt bridge interaction in I(N)---C₁ inter-domain of hIMPDH-I, I(N)---C₂ of IMPDH-II and C₁---I(C) of nhIMPDH-II are discriminative features among the isoforms. The I(N)---C₂ recognition in hIMPDH-II (1B3O) is missing in type-I isoform (1JCN). The salt bridge interaction D232---K238 at the surface of protein and the involvement of three conserved water molecules or the hydrophilic centers (WA²³²(OD1), WB ²³²(OD2) and W²³⁸(NZ)) to those acidic and basic residues seem to be unique in hIMPDH-II. The hydrophilic susceptibility, geometrical and electronic consequences of this salt bridge interaction could be useful to design the topology of specific inhibitor for hIMPDH-II which may not be effective for hIMPDH-I. Possibly, the aliphatic ligand containing carboxyl, amide or hydrophilic groups with flexible structure may be implicated for hIMPDH-II inhibitor design using the conserved water mimic drug design protocol.

  16. A new insight on the core-shell structure of zerovalent iron nanoparticles and its application for Pb(II) sequestration.

    PubMed

    Zhang, Yalei; Su, Yiming; Zhou, Xuefei; Dai, Chaomeng; Keller, Arturo A

    2013-12-15

    Nanoscale zerovalent iron (nZVI) has shown a high efficacy for removing heavy metals from liquid solution. However, its removal capacity has not been fully explored due to its common shell composition (FeOOH). In this study, a much higher removal capacity of Pb(II) is observed (1667 mg Pb(II)/gFe), which is over 100% higher than the highest removal capacity of nZVI reported before. High-resolution X-ray photoelectron spectroscopy (HR-XPS) reveals that through restricting the dehydration process of Fe(OH)3, nZVI can acquire a unique shell, which is composed of 45.5% Fe(OH)3 and 54.5% FeOOH. The presence of Fe(OH)3 suppresses the reduction of Pb(II), but greatly promotes the co-precipitation and adsorption of Pb(II). Combining the ratio of Fe-released to Pb-immobilized and the result of HR-XPS, a reaction between Fe(0) core, Fe(OH)3, and Pb(II) is proposed. The Fe released from the Fe(0) core leads to the core depletion, observed by transmission electron microscopy (TEM) under high Pb(II) loading. While temperature has little influence on the removal capacity, pH affects the removal capacity greatly. pH<4.5 favors Fe dissolution, while pH>4.5 promotes Pb(II) adsorption. Given the high Pb removal capacity via the Fe(OH)3 shell, nZVI can be used to remedy Pb(II) contamination.

  17. New insights into the coordination of Cu(II) by the amyloid-B 16 peptide from Fourier transform IR spectroscopy and isotopic labeling.

    PubMed

    El Khoury, Youssef; Dorlet, Pierre; Faller, Peter; Hellwig, Petra

    2011-12-15

    Alzheimer's disease is a neurodegenerative disorder in which the formation of amyloid-β (Aβ) aggregates plays a causative role. There is ample evidence that Cu(II) can bind to Aβ and modulate its aggregation. Moreover, Cu(II) bound to Aβ might be involved in the production of reactive oxygen species, a process supposed to be involved in the Alzheimer's disease. The native Aβ40 contains a high affinity binding site for Cu(II), which is comprised in the N-terminal portion. Thus, Aβ16 (amino acid 1-16 of Aβ) has often been used as a model for Cu(II)-binding to monomeric Aβ. The Cu(II)-binding to Aβ is pH dependent and at pH 7.4, two different type of Cu(II) coordinations exist in equilibrium. These two forms are predominant at pH 6.5 and pH 9.0. In either form, a variety of studies show that the N-terminal Asp and the three His play a key role in the coordination, although the exact binding of these amino acids has not been addressed. Therefore, we studied the coordination modes of Cu(II) at pH 6.5 and 9.0 with the help of Fourier transform infrared (FTIR) spectroscopy. Combined with isotopic labeling of the amino acids involved in the coordination sphere, the data points toward the coordination of Cu(II) via the carboxylate of Asp1 at both pH values in a pseudobridging monovalent fashion. At low pH, His6 binds copper via Nτ, while His13 and His14 are bound via Nπ. At high pH, direct evidence is given on the coordination of Cu(II) via the Nτ atom of His6. Additionally, this study clearly shows the effect of Cu(II) binding on the protonation state of the His residues where a proton displacement takes places on the nitrogen atoms of the imidazole ring.

  18. Aliphatic C-C Bond Cleavage of α-Hydroxy Ketones by Non-Heme Iron(II) Complexes: Mechanistic Insight into the Reaction Catalyzed by 2,4'-Dihydroxyacetophenone Dioxygenase.

    PubMed

    Rahaman, Rubina; Paria, Sayantan; Paine, Tapan Kanti

    2015-11-16

    2,4'-Dihydroxyacetophenone dioxygenase (DAD) is a bacterial non-heme enzyme that carries out oxygenative aliphatic C-C bond cleavage of 2,4'-dihydroxyacetophenone (an α-hydroxy ketone) with the incorporation of both the oxygen atoms of dioxygen into the cleavage products. The crystal structure of the iron enzyme DAD has recently been determined, but very little is known about the mechanism of the C-C bond cleavage reaction. With the objective of gaining insights into the mechanism of the reaction catalyzed by DAD, six new biomimetic iron(II)-α-hydroxy ketone complexes, [(Tp(Ph2))Fe(II)(PHAP)] (1), [(Tp(Ph2))Fe(II)(HCH)] (2), [(Tp(Ph2))Fe(II)(HBME)] (3), [(Tp(Ph2))Fe(II)(CHPE)] (4), [(6-Me3-TPA)Fe(II)(PHAP)](+) (5), and [(6-Me3-TPA)Fe(II)(HCH)](+) (6) (Tp(Ph2) = hydrotris(3,5-diphenylpyrazol-1-yl)borate, 6-Me3-TPA = tris(6-methyl-2-pyridylmethyl)amine, PHAP-H = 2-phenyl-2-hydroxyacetophenone, HCH-H = 2-hydroxycyclohexanone, HBME-H = 2-hydroxy-1,2-bis(4-methoxyphenyl)ethanone, and CHPE-H = 1-(4-chlorophenyl)-2-hydroxy-2-phenylethanone), have been isolated and characterized. The single-crystal X-ray structure of 2 shows a five-coordinate iron(II) complex with one tridentate facial ligand and a monoanionic bidentate α-hydroxy ketone, resulting in a distorted-square-pyramidal coordination geometry at the iron center. The iron(II) complexes react with dioxygen to oxidatively cleave the aliphatic C-C bonds of the coordinated α-hydroxy ketones to afford 2 equiv of carboxylic acids. Mechanistic studies reveal that the C-C bond cleavage reaction proceeds through an intradiol pathway. Additionally, the coordinated α-hydroxy ketones in all of the complexes, except in complex 4, undergo two-electron oxidation to form the corresponding 1,2-diketones. However, the yields of 1,2-diketones are higher with the iron complexes of the tripodal N4 ligand (6-Me3-TPA) in comparison to the facial N3 ligand (Tp(Ph2)). These results strongly support the natural selection of a facial N3

  19. Solution Conditions Affect the Ability of the K30D Mutation To Prevent Amyloid Fibril Formation by Apolipoprotein C-II: Insights from Experiments and Theoretical Simulations.

    PubMed

    Mao, Yu; Todorova, Nevena; Zlatic, Courtney O; Gooley, Paul R; Griffin, Michael D W; Howlett, Geoffrey J; Yarovsky, Irene

    2016-07-12

    Apolipoproteins form amphipathic helical structures that bind lipid surfaces. Paradoxically, lipid-free apolipoproteins display a strong propensity to form cross-β structure and self-associate into disease-related amyloid fibrils. Studies of apolipoprotein C-II (apoC-II) amyloid fibrils suggest that a K30-D69 ion pair accounts for the dual abilities to form helix and cross-β structure. Consistent with this is the observation that a K30D mutation prevents fibril formation under standard fibril forming conditions. However, we found that fibril formation by K30D apoC-II proceeded readily at low pH and a higher salt or protein concentration. Structural analysis demonstrated that K30D apoC-II fibrils at pH 7 have a structure similar to that of the wild-type fibrils but are less stable. Molecular dynamics simulations of the wild-type apoC-II fibril model at pH 7 and 3 showed that the loss of charge on D69 at pH 3 leads to greater separation between residues K30 and D69 within the fibril with a corresponding reduction in β-strand content around residue 30. In contrast, in simulations of the K30D mutant model at pH 7 and 3, residues D30 and D69 moved closer at pH 3, accompanied by an increase in β-strand content around residue 30. The simulations also demonstrated a strong dominance of inter- over intramolecular contacts between ionic residues of apoC-II and suggested a cooperative mechanism for forming favorable interactions between the individual strands under different conditions. These observations demonstrate the important role of the buried K30-D69 ion pair in the stability and solution properties of apoC-II amyloid fibrils.

  20. Insights into the history of a bacterial group II intron remnant from the genomes of the nitrogen-fixing symbionts Sinorhizobium meliloti and Sinorhizobium medicae.

    PubMed

    Toro, N; Martínez-Rodríguez, L; Martínez-Abarca, F

    2014-10-01

    Group II introns are self-splicing catalytic RNAs that act as mobile retroelements. In bacteria, they are thought to be tolerated to some extent because they self-splice and home preferentially to sites outside of functional genes, generally within intergenic regions or in other mobile genetic elements, by mechanisms including the divergence of DNA target specificity to prevent target site saturation. RmInt1 is a mobile group II intron that is widespread in natural populations of Sinorhizobium meliloti and was first described in the GR4 strain. Like other bacterial group II introns, RmInt1 tends to evolve toward an inactive form by fragmentation, with loss of the 3' terminus. We identified genomic evidence of a fragmented intron closely related to RmInt1 buried in the genome of the extant S. meliloti/S. medicae species. By studying this intron, we obtained evidence for the occurrence of intron insertion before the divergence of ancient rhizobial species. This fragmented group II intron has thus existed for a long time and has provided sequence variation, on which selection can act, contributing to diverse genetic rearrangements, and to generate pan-genome divergence after strain differentiation. The data presented here suggest that fragmented group II introns within intergenic regions closed to functionally important neighboring genes may have been microevolutionary forces driving adaptive evolution of these rhizobial species.

  1. Affinity, speciation, and molecular features of copper(II) complexes with a prion tetraoctarepeat domain in aqueous solution: insights into old and new results.

    PubMed

    Di Natale, Giuseppe; Ősz, Katalin; Kállay, Csilla; Pappalardo, Giuseppe; Sanna, Daniele; Impellizzeri, Giuseppe; Sóvágó, Imre; Rizzarelli, Enrico

    2013-03-11

    Characterization of the copper(II) complexes formed with the tetraoctarepeat peptide at low and high metal-to-ligand ratios and in a large pH range, would provide a breakthrough in the interpretation of biological relevance of the different metal complexes of copper(II)-tetraoctarepeat system. In the present work, the potentiometric, UV/Vis, circular dichroism (CD), and electron paramagnetic resonance (EPR) studies were carried out on copper(II) complexes with a PEG-ylated derivative of the tetraoctarepeats peptide sequence (Ac-PEG27 -(PHGGGWGQ)4 -NH2 ) and the peptide Ac-(PHGGGWGQ)2 -NH2 . Conjugation of tetraoctarepeat peptide sequence with polyethyleneglycol improved the solubility of the copper(II) complexes. The results enable a straightforward explanation of the conflicting results originated from the underestimation of all metal-ligand equilibria and the ensuing speciation. A complete and reliable speciation is therefore obtained with the released affinity and binding details of the main complexes species formed in aqueous solution. The results contribute to clarify the discrepancies of several studies in which the authors ascribe the redox activity of copper(II)-tetraoctarepeat system considering only the average effects of several coexisting species with very different stoichiometries and binding modes.

  2. Insights into the binding mode of sulphamates and sulphamides to hCA II: crystallographic studies and binding free energy calculations.

    PubMed

    De Simone, Giuseppina; Langella, Emma; Esposito, Davide; Supuran, Claudiu T; Monti, Simona Maria; Winum, Jean-Yves; Alterio, Vincenzo

    2017-12-01

    Sulphamate and sulphamide derivatives have been largely investigated as carbonic anhydrase inhibitors (CAIs) by means of different experimental techniques. However, the structural determinants responsible for their different binding mode to the enzyme active site were not clearly defined so far. In this paper, we report the X-ray crystal structure of hCA II in complex with a sulphamate inhibitor incorporating a nitroimidazole moiety. The comparison with the structure of hCA II in complex with its sulphamide analogue revealed that the two inhibitors adopt a completely different binding mode within the hCA II active site. Starting from these results, we performed a theoretical study on sulphamate and sulphamide derivatives, demonstrating that electrostatic interactions with residues within the enzyme active site play a key role in determining their binding conformation. These findings open new perspectives in the design of effective CAIs using the sulphamate and sulphamide zinc binding groups as lead compounds.

  3. CoaTx-II, a new dimeric Lys49 phospholipase A2 from Crotalus oreganus abyssus snake venom with bactericidal potential: Insights into its structure and biological roles.

    PubMed

    Almeida, J R; Lancellotti, M; Soares, A M; Calderon, L A; Ramírez, D; González, W; Marangoni, S; Da Silva, S L

    2016-09-15

    Snake venoms are rich and intriguing sources of biologically-active molecules that act on target cells, modulating a diversity of physiological functions and presenting promising pharmacological applications. Lys49 phospholipase A2 is one of the multifunctional proteins present in these complex secretions and, although catalytically inactive, has a variety of biological activities, including cytotoxic, antibacterial, inflammatory, antifungal activities. Herein, a Lys49 phospholipase A2, denominated CoaTx-II from Crotalus oreganus abyssus, was purified and structurally and pharmacologically characterized. CoaTx-II was isolated with a high degree of purity by a combination of two chromatographic steps; molecular exclusion and reversed-phase high performance liquid chromatography. This toxin is dimeric with a mass of 13868.2 Da (monomeric form), as determined by mass spectrometry. CoaTx-II is rich in Arg and Lys residues and displays high identity with other Lys49 PLA2 homologues, which have high isoelectric points. The structural model of dimeric CoaTx-II shows that the toxin is non-covalently stabilized. Despite its enzymatic inactivity, in vivo CoaTx-II caused local muscular damage, characterized by increased plasma creatine kinase and confirmed by histological alterations, in addition to an inflammatory activity, as demonstrated by mice paw edema induction and pro-inflammatory cytokine IL-6 elevation. CoaTx-II also presents antibacterial activity against gram negative (Pseudomonas aeruginosa 31NM, Escherichia coli ATCC 25922) and positive (Staphyloccocus aureus BEC9393 and Rib1) bacteria. Therefore, data show that this newly purified toxin plays a central role in mediating the degenerative events associated with envenomation, in addition to demonstrating antibacterial properties, with potential for use in the development of strategies for antivenom therapy and combating antibiotic-resistant bacteria.

  4. Combined EXAFS and DFT Structure Calculations Provide Structural Insights into the 1:1 Multi-Histidine Complexes of CuII, CuI and ZnII with the Tandem Octarepeats of the Mammalian Prion Protein

    PubMed Central

    Pushie, M. Jake; Nienaber, Kurt H.; McDonald, Alex; Millhauser, Glenn L.; George, Graham N.

    2014-01-01

    The metal coordinating properties of the prion protein (PrP) have been the subject of intense focus and debate since the first reports of copper interaction with PrP just before the turn of the century. The picture of metal coordination to PrP has been improved and refined over the past decade, and yet the structural details of the various metal coordination modes have not been fully elucidated in some cases. Herein we employ X-ray absorption near edge spectroscopy as well as extended X-ray absorption fine structure (EXAFS) spectroscopy to structurally characterize the dominant 1:1 coordination modes for CuII, CuI and ZnII with an N-terminal fragment of PrP. The PrP fragment constitutes four tandem repeats representative of the mammalian octarepeat domain, designated OR4, which is also the most studied PrP fragment for metal interactions, making our findings applicable to a large body of previous work. Density functional theory (DFT) calculations provide additional structural and thermodynamic data, and candidate structures are used to inform EXAFS data analysis. The optimized geometries from DFT calculations are used to identify potential coordination complexes for multi-histidine coordination of CuII, CuI and ZnII in an aqueous medium, modeled using 4-methylimidazole to represent the histidine side chain. Through a combination of in silico coordination chemistry as well as rigorous EXAFS curve fitting, using full multiple scattering on candidate structures from DFT calculations, we have characterized the predominant coordination modes for the 1:1 complexes of CuII, CuI and ZnII with the OR4 peptide at pH 7.4 at atomic resolution, which are best represented as a square planar [CuII(His)4]2+, digonal [CuI(His)2]+ and tetrahedral [ZnII(His)3(OH2)]2+, respectively. PMID:25042361

  5. Establishment of trophic continuum in the food web of the Yellow Sea and East China Sea ecosystem: insight from carbon and nitrogen stable isotopes.

    PubMed

    Cai, Deling; Li, Hongyan; Tang, Qisheng; Sun, Yao

    2005-12-01

    Stable carbon and nitrogen isotope ratios (delta (13)C and delta (15)N) are used to study the trophic structure of food web in the Yellow Sea and East China Sea ecosystem. The trophic continuum of pelagic food web from phytoplankton to top preyer was elementarily established, and a trophic structure diagram in the Yellow Sea and East China Sea was outlined in combination with carbon isotopic data of benthic organisms, which is basically consistent with and makes some improvements on the simplified Yellow Sea food web and the trophic structure diagram drawn based on the biomass of main resource population during 1985-1986. This result indicates that the stable isotope method is a potential useful means for further studying the complete marine food web trophic continuum from viruses to top predators and food web stability.

  6. The role of rifting in the development of the continental margins of the southwest subbasin, South China Sea: Insights from an OBS experiment

    NASA Astrophysics Data System (ADS)

    Lü, Chuanchuan; Hao, Tianyao; Lin, Jian; Qiu, Xuelin

    2016-11-01

    The continental margins of the southwest subbasin in the South China Sea mark a unique transition from multi-stages magma-poor continental rifting to seafloor spreading. We used reflection and refraction profiles across the margins to investigate the rifting process of the crust. Combining with the other seismic profiles acquired earlier, we focused on the comparative geological interpretation from the result of multichannel seismic analysis and wide-angle seismic tomography. Our result provides the evidence of upper crustal layer with abundant fractures below the acoustic basement with a P-wave velocity from 4.0 to 5.5 km s-1. It indicates extensive deformation of the brittle crust during the continental rifting and can make a good explanation for the observed extension discrepancy in the rift margins of the South China Sea. The seismic chronostratigraphic result shows the possibility of the intra-continental extension center stayed focused for quite a long time in Eocene. Additionally, our evidence suggested that continental margin of the southwest subbasin had experienced at least three rifting stages and the existence of the rigid blocks is an appropriate explanation to the asymmetric rifting of the South China Sea.

  7. The role of rifting in the development of the continental margins of the southwest subbasin, South China Sea: Insights from an OBS experiment

    NASA Astrophysics Data System (ADS)

    Lü, Chuanchuan; Hao, Tianyao; Lin, Jian; Qiu, Xuelin

    2017-06-01

    The continental margins of the southwest subbasin in the South China Sea mark a unique transition from multi-stages magma-poor continental rifting to seafloor spreading. We used reflection and refraction profiles across the margins to investigate the rifting process of the crust. Combining with the other seismic profiles acquired earlier, we focused on the comparative geological interpretation from the result of multichannel seismic analysis and wide-angle seismic tomography. Our result provides the evidence of upper crustal layer with abundant fractures below the acoustic basement with a P-wave velocity from 4.0 to 5.5 km s-1. It indicates extensive deformation of the brittle crust during the continental rifting and can make a good explanation for the observed extension discrepancy in the rift margins of the South China Sea. The seismic chronostratigraphic result shows the possibility of the intra-continental extension center stayed focused for quite a long time in Eocene. Additionally, our evidence suggested that continental margin of the southwest subbasin had experienced at least three rifting stages and the existence of the rigid blocks is an appropriate explanation to the asymmetric rifting of the South China Sea.

  8. Giant Panda Genomic Data Provide Insight into the Birth-and-Death Process of Mammalian Major Histocompatibility Complex Class II Genes

    PubMed Central

    Wan, Qiu-Hong; Zeng, Chang-Jun; Ni, Xiao-Wei; Pan, Hui-Juan; Fang, Sheng-Guo

    2009-01-01

    To gain an understanding of the genomic structure and evolutionary history of the giant panda major histocompatibility complex (MHC) genes, we determined a 636,503-bp nucleotide sequence spanning the MHC class II region. Analysis revealed that the MHC class II region from this rare species contained 26 loci (17 predicted to be expressed), of which 10 are classical class II genes (1 DRA, 2 DRB, 2 DQA, 3 DQB, 1 DYB, 1 DPA, and 2 DPB) and 4 are non-classical class II genes (1 DOA, 1 DOB, 1 DMA, and 1 DMB). The presence of DYB, a gene specific to ruminants, prompted a comparison of the giant panda class II sequence with those of humans, cats, dogs, cattle, pigs, and mice. The results indicated that birth and death events within the DQ and DRB-DY regions led to major lineage differences, with absence of these regions in the cat and in humans and mice respectively. The phylogenetic trees constructed using all expressed alpha and beta genes from marsupials and placental mammals showed that: (1) because marsupials carry loci corresponding to DR, DP, DO and DM genes, those subregions most likely developed before the divergence of marsupials and placental mammals, approximately 150 million years ago (MYA); (2) conversely, the DQ and DY regions must have evolved later, but before the radiation of placental mammals (100 MYA). As a result, the typical genomic structure of MHC class II genes for the giant panda is similar to that of the other placental mammals and corresponds to BTNL2∼DR1∼DQ∼DR2∼DY∼DO_box∼DP∼COL11A2. Over the past 100 million years, there has been birth and death of mammalian DR, DQ, DY, and DP genes, an evolutionary process that has brought about the current species-specific genomic structure of the MHC class II region. Furthermore, facing certain similar pathogens, mammals have adopted intra-subregion (DR and DQ) and inter-subregion (between DQ and DP) convergent evolutionary strategies for their alpha and beta genes, respectively. PMID:19127303

  9. Investigation and control of a Plasmodium falciparum malaria outbreak in Shan Special Region II of Myanmar along the China-Myanmar Border from June to December 2014.

    PubMed

    Liu, Hui; Xu, Jian-Wei; Yang, Heng-Lin; Li, Mei; Sun, Cheng-De; Yin, Yi-Jie; Zheng, Zhi-Liang; Zhang, Guang-Yun; Yu, Ai-Shui; Yang, Yong-Hui; Li, Chun-Hui; Ai, Shui

    2016-04-25

    From 2007 to 2013, intensive control measures reduced malaria burden by 90 % along the China-Myanmar border. However, despite these measures a P. falciparum malaria outbreak was reported in the Shan Special Region II of Myanmar in June of 2014. Epidemiological, parasitological and entomological investigations were performed. Dihydroartemisinin piperaquine (DAPQ) was immediately administered to treat parasite positive individuals. Long lasting insecticidal nets (LLIN), indoor residual spraying (IRS) with insecticides and behavior change communication (BCC) were also provided for outbreak control. An embedded efficacy study was conducted evaluating DP. Molecular genotyping via polymerase chain reaction (PCR) was performed on the Kelch gene on chromosome 13. All infections were identified as Plasmodium falciparum by RDT and microscopy. Two fatalities resulted from the outbreak. The attack rate was 72.8 % (67/92) and the incidence density rate was 14.2 per 100 person-weeks. The positive rate of rapid diagnostic test (RDT) was 72.2 % (65/90) and microscopically-determine parasite rate 42.2 % (38/90). Adjusted odds ratio (OR) of multivariate logistic regression analysis for aged <15 years, 15-45 years, inappropriate treatment from a private healer and lack of bed nets were 13.51 (95 % confidence interval, 2.21-105.89), 7.75 (1.48-44.97), 3.78 (1.30-46.18) and 3.21(1.21-15.19) respectively. In the six surrounding communities of the outbreak site, positive RDT rate was 1.2 % (4/328) and microscopically-determine parasite rate 0.6 % (2/328). Two light traps collected a total of 110 anopheline mosquitoes including local vectors, An. minimus, An. sinensis and An. maculates. After intensive control, the detection of malaria attacks, parasites and antigen were reduced to zero between July 1 and December 1, 2014. The cure rate of P. falciparum patients at day 42 was 94.3 % (95 % CI, 80.8-99.3 %). The PCR did not detect K13-propeller mutations. Imported P. falciparum caused the

  10. Properties of impurity-bearing ferrihydrite II: Insights into the surface structure and composition of pure, Al- and Si-bearing ferrihydrite from Zn(II) sorption experiments and Zn K-edge X-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Cismasu, A. Cristina; Levard, Clément; Michel, F. Marc; Brown, Gordon E.

    2013-10-01

    Naturally occurring ferrihydrite often contains impurities such as Al and Si, which can impact its chemical reactivity with respect to metal(loid) adsorption and (in)organic or microbially induced reductive dissolution. However, the surface composition of impure ferrihydrites is not well constrained, and this hinders our understanding of the factors controlling the surface reactivity of these nanophases. In this study, we conducted Zn(II) adsorption experiments combined with Zn K-edge X-ray absorption spectroscopy measurements on pure ferrihydrite (Fh) and Al- or Si-bearing ferrihydrites containing 10 and 20 mol% Al or Si (referred to as 10AlFh, 20AlFh and 10SiFh, 20SiFh) to evaluate Zn(II) uptake in relation to Zn(II) speciation at their surfaces. Overall, Zn(II) uptake at the surface of AlFh is similar to that of pure Fh, and based on Zn K-edge EXAFS data, Zn(II) speciation at the surface of Fh and AlFh also appears similar. Binuclear bidentate IVZn-VIFe complexes (at ∼3.46 Å (2C[1]) and ∼3.25 Å (2C[2])) were identified at low Zn(II) surface coverages from Zn K-edge EXAFS fits. With increasing Zn(II) surface coverage, the number of second-neighbor Fe ions decreased, which was interpreted as indicating the formation of IVZn polymers at the ferrihydrite surface, and a deviation from Langmuir uptake behavior. Zn(II) uptake at the surface of SiFh samples was more significant than at Fh and AlFh surfaces, and was attributed to the formation of outer-sphere complexes (on average 24% of sorbed Zn). Although similar Zn-Fe/Zn distances were obtained for the Zn-sorbed SiFh samples, the number of Fe second neighbors was lower in comparison with Fh. The decrease in second-neighbor Fe is most pronounced for sample 20SiFh, suggesting that the amount of reactive surface Fe sites diminishes with increasing Si content. Although our EXAFS results shown here do not provide evidence for the existence of Zn-Al or Zn-Si complexes, their presence is not excluded for Zn-sorbed Al

  11. Preparing for JWST Observations. Insights from First Light and Assembly of Galaxies GTO Programs II: Studying galaxy properties with MIRI Spectroscopy

    NASA Astrophysics Data System (ADS)

    Garcia Marin, Macarena; Wright, Gillian; Rieke, George; MIRI GTO Team

    2017-06-01

    The MIRI instrument, a result of the collaborative work of a consortium of European and US institutes, is the only Mid-IR science instrument on board of the James Webb Space Telescope. It will achieve unprecedented sensitivity and spatial resolution in the 5-28 microns wavelength range. A significant part of the MIRI GTO time will be dedicated to extragalactic observations, with the aim of covering a broad range of redshifts and giving new insights to galaxy history through time. While some of the programme will use deep MIRI images complemented with NIR observations, in this talk I will focus on the spectroscopic studies of galaxies planned by the MIRI team. At redshifts of about 7-8 we will study the reionization epoch, by observing spectroscopically confirmed targets. The strong emission lines predicted for these galaxies will be measured with the MIRI MRS (an integral field spectrometer).Moving closer in redshift, MIRI will be able to provide spatially resolved spectroscopy of massive dusty star forming galaxies at redshifts of about 3 or higher. This will give us the opportunity to study obscured AGNs, internal extinction and star formation activity, and gas-kpc scales kinematics. Finally, in the local Universe, we will observe the nuclei of well-known nearby galaxies with the MIRI MRS and the NIRSpec IFU. The spectra will yield new insights into the distribution, physical conditions, and kinematics of the various gas components (ionized, atomic, or molecular) in the immediate vicinity of the nucleus.In this contribution I will present this overall spectroscopic GTO program, giving insight into the observing strategies we plan to use for optimally implementing our observations.

  12. Vegetation and climate history in arid western China during MIS2: New insights from pollen and grain-size data of the Balikun Lake, eastern Tien Shan

    NASA Astrophysics Data System (ADS)

    Zhao, Yongtao; An, Cheng-Bang; Mao, Limi; Zhao, Jiaju; Tang, Lingyu; Zhou, Aifeng; Li, Hu; Dong, Weimiao; Duan, Futao; Chen, Fahu

    2015-10-01

    Marine Isotope Stage (MIS) 2 is mostly a cold period encompassing the Last Glacial Maximum (LGM), but the regional expression of MIS2 in arid areas of China is not well known. In this paper, we use high-resolution lacustrine pollen and grain-size records from Balikun Lake to infer vegetation, lake evolution, and climate in arid western China during MIS2. Our results suggest that: 1) the regional vegetation around Balikun was mainly dominated by desert and/or desert-steppe, and Balikun Lake was relatively shallow and experienced high aeolian input during MIS2; 2) distinctive runoff from mountain glacial meltwater in the eastern parts of the Balikun basin caused a high relative abundance of Artemisia pollen during the LGM (26.5-19.2 cal kyr BP), while simultaneously the desert areas expanded as indicated by the high abundance of desert shrubs (e.g., Elaeagnaceae, Rhamnaceae, Hippophae). This cold and dry LGM climate triggered a substantial lowering of lake level; 3) an extremely cold and dry climate prevailing from 17.0 to 15.2 cal kyr BP, correlated with Heinrich event 1 (H1), would explain the low vegetation cover found then; and 4) the warm and humid Bølling/Allerød interstadial (BA: ca. 15-ca. 13 cal kyr BP) is clearly recorded in the Balikun region by the development of wetland herb communities (e.g., Poaceae, Cyperaceae, Typha), and the lake level rose due to increased runoff. Our results challenge the traditional view of cold and wet climatic conditions and high lake levels in arid western China during the LGM, and we propose that changes in local temperature modulated by July insolation was an indispensable factor in triggering vegetation evolution in the Balikun region during MIS2.

  13. Early Paleozoic intracontinental orogeny in the Yunkai domain, South China Block: New insights from field observations, zircon U-Pb geochronological and geochemical investigations

    NASA Astrophysics Data System (ADS)

    Yan, Chaolei; Shu, Liangshu; Michel, Faure; Chen, Yan; Li, Cheng

    2017-01-01

    Debate on whether the Early Paleozoic tectono-magmatic event in South China is related to a subduction-collision or an intracontinental orogen has been lasted for decades within the geoscience community. This study deals with LA-ICP-MS zircon U-Pb ages, whole-rock chemistry, rare earth elements, trace elements and Hf isotopes from granitoid samples collected in the Yunkai domain in order to better constrain the Early Paleozoic tectonic evolution of the South China Block. The weighted mean 206Pb/238U ages for eight samples range from 426 Ma to 443 Ma, representing the crystallization ages of the magma. Fourteen samples were analyzed for geochemistry, all of which are characterized by a peraluminous signature with A/CNK values greater than 1.0. The REE geochemistry reveals enrichment in light rare earth element. LREE/HREE values range from 2.81 to 30.36 and (La/Yb)N vary from 1.23 to 55.14 (mean of 14 analyses is 14.69). All the samples exhibit distinct negative Ba, Sr and Nb anomalies and enrichment in Rb, Th, U and Pb. Hf isotopic analyses indicate negative εHf (t) values mainly ranging from - 3 to - 12, corresponding to two model age distributing from 1637 Ma to 2208 Ma. The geochemical analyses indicate that the Silurian granitic magmas in the Yunkai domain were derived from partial melting of crustal materials with little or no input of mantle source. These new data support the intracontinental subduction model already proposed to account for the Early Paleozoic tectonic, metamorphic and magmatic event of South China.

  14. Health and social impacts of biomass gasification for household energy in rural China: Assessment from three perspectives and emergent insights from their synthesis

    NASA Astrophysics Data System (ADS)

    Fischer, Susan Lynn

    Solid fuels such as coal, wood, and crop straw supply some fraction of household cooking and heating fuel for more than one billion people in China. As these fuels do not generally combust cleanly in household stoves, their use levies large health and environmental burdens, particularly in rural regions. Production of clean-burning fuels from agricultural residue offers one prospect for mitigating health and social burdens imposed by household use of solid fuels. This dissertation explores the question: how might production of clean-burning household fuels from agricultural residues affect human health and social conditions in rural China? I approach this question from three perspectives. First, a technically plausible but currently unproven village-scale energy technology is explored in a scenario bounded by natural resources and substantiated by engineering specifications, estimates of indoor exposures to air pollution, and epidemiological analyses. This analysis asks at the national (China) level: how might rural health burdens be mitigated and greenhouse gas emissions reduced by such a technology? Secondly, I perform wintertime indoor air quality monitoring in a Chinese village where coal and wood are used for heating and a variety of solid and "improved" fuels, including gas and electricity, are used for cooking. This fieldwork characterizes rural indoor air quality in terms of 24-hour and peak-period (1-hour) carbon monoxide (CO) and particulate matter (PM) concentrations and 24-hour airborne nicotine (a proxy for environmental tobacco smoke), as well as daily exposures of primary cooks to CO. I also explore relationships between observed measures of indoor air quality and investigate household structural and behavioral factors as determinants of air quality. The third perspective is an ethnographic case study of a demonstration project for production of household fuel from agricultural residue in Hechengli Village, Jilin Province, China. With an emphasis on

  15. Insight into hydrolytic reaction of N-acetylated L-histidylglycine dipeptide with novel mechlorethamine platinum(II) complex. NMR and DFT study of the hydrolytic reaction.

    PubMed

    Petrović, Zorica D; Petrović, Vladimir P; Simijonović, Dušica; Marković, Svetlana

    2011-09-28

    The reaction of K(2)PtCl(4) with the alkylating agent mechlorethamine hydrochloride, at a molar ratio of 1:2, results in the formation of 2-chloro-N-(2-chloroethyl)-N-methylethylammonium-tetrachloridoplatinate(II) complex. The hydrolytic activity of the novel Pt(II) complex was tested in the reaction with N-acetylated L-histidylglycine dipeptide at a molar ratio 1:1. It was shown that the hydrolytic reaction, performed at 60 °C in acidic medium, leads to the regioselective cleavage of the amide bond involving the carboxylic group of histidine. Density functional theory was used to explore the structures of the proposed participants in the hydrolytic reaction.

  16. Binding of Sudan II and IV to lecithin liposomes and E. coli membranes: insights into the toxicity of hydrophobic azo dyes

    PubMed Central

    Li, Lu; Gao, Hong-Wen; Ren, Jiao-Rong; Chen, Ling; Li, Yu-Cheng; Zhao, Jian-Fu; Zhao, He-Ping; Yuan, Yuan

    2007-01-01

    Background Sudan red compounds are hydrophobic azo dyes, still used as food additives in some countries. However, they have been shown to be unsafe, causing tumors in the liver and urinary bladder in rats. They have been classified as category 3 human carcinogens by the International Agency for Research on Cancer. A number of hypotheses that could explain the mechanism of carcinogenesis have been proposed for dyes similar to the Sudan red compounds. Traditionally, investigations of the membrane toxicity of organic substances have focused on hydrocarbons, e.g. polycyclic aromatic hydrocarbons (PAHs), and DDT. In contrast to hydrocarbons, Sudan red compounds contain azo and hydroxy groups, which can form hydrogen bonds with the polar head groups of membrane phospholipids. Thus, entry may be impeded. They could have different toxicities from other lipophilic hydrocarbons. The available data show that because these compounds are lipophilic, interactions with hydrophobic parts of the cell are important for their toxicity. Lipophilic compounds accumulate in the membrane, causing expansion of the membrane surface area, inhibition of primary ion pumps and increased proton permeability. Results This work investigated the interactions of the amphiphilic compounds Sudan II and IV with lecithin liposomes and live Escherichia coli (E. coli). Sudan II and IV binding to lecithin liposomes and live E. coli corresponds to the Langmuir adsorption isotherm. In the Sudan red compounds – lecithin liposome solutions, the binding ratio of Sudan II to lecithin is 1/31 and that of Sudan IV to 1/314. The binding constant of the Sudan II-lecithin complex is 1.75 × 104 and that of the Sudan IV-lecithin complex 2.92 × 105. Besides, the influences of pH, electrolyte and temperature were investigated and analyzed quantitatively. In the Sudan red compounds – E.coli mixture, the binding ratios of Sudan II and Sudan IV to E.coli membrane phospholipid are 1/29 and 1/114. The binding constants

  17. Multiple parasites mediate balancing selection at two MHC class II genes in the fossorial water vole: insights from multivariate analyses and population genetics.

    PubMed

    Tollenaere, C; Bryja, J; Galan, M; Cadet, P; Deter, J; Chaval, Y; Berthier, K; Ribas Salvador, A; Voutilainen, L; Laakkonen, J; Henttonen, H; Cosson, J-F; Charbonnel, N

    2008-09-01

    We investigated the factors mediating selection acting on two MHC class II genes (DQA and DRB) in water vole (Arvicola scherman) natural populations in the French Jura Mountains. Population genetics showed significant homogeneity in allelic frequencies at the DQA1 locus as opposed to neutral markers (nine microsatellites), indicating balancing selection acting on this gene. Moreover, almost exhaustive screening for parasites, including gastrointestinal helminths, brain coccidia and antibodies against viruses responsible for zoonoses, was carried out. We applied a co-inertia approach to the genetic and parasitological data sets to avoid statistical problems related to multiple testing. Two alleles, Arte-DRB-11 and Arte-DRB-15, displayed antagonistic associations with the nematode Trichuris arvicolae, revealing the potential parasite-mediated selection acting on DRB locus. Selection mechanisms acting on the two MHC class II genes thus appeared different. Moreover, overdominance as balancing selection mechanism was showed highly unlikely in this system.

  18. Biophysical Insights into How Spike Threshold Depends on the Rate of Membrane Potential Depolarization in Type I and Type II Neurons

    PubMed Central

    Yi, Guo-Sheng; Wang, Jiang; Tsang, Kai-Ming; Wei, Xi-Le; Deng, Bin

    2015-01-01

    Dynamic spike threshold plays a critical role in neuronal input-output relations. In many neurons, the threshold potential depends on the rate of membrane potential depolarization (dV/dt) preceding a spike. There are two basic classes of neural excitability, i.e., Type I and Type II, according to input-output properties. Although the dynamical and biophysical basis of their spike initiation has been established, the spike threshold dynamic for each cell type has not been well described. Here, we use a biophysical model to investigate how spike threshold depends on dV/dt in two types of neuron. It is observed that Type II spike threshold is more depolarized and more sensitive to dV/dt than Type I. With phase plane analysis, we show that each threshold dynamic arises from the different separatrix and K+ current kinetics. By analyzing subthreshold properties of membrane currents, we find the activation of hyperpolarizing current prior to spike initiation is a major factor that regulates the threshold dynamics. The outward K+ current in Type I neuron does not activate at the perithresholds, which makes its spike threshold insensitive to dV/dt. The Type II K+ current activates prior to spike initiation and there is a large net hyperpolarizing current at the perithresholds, which results in a depolarized threshold as well as a pronounced threshold dynamic. These predictions are further attested in several other functionally equivalent cases of neural excitability. Our study provides a fundamental description about how intrinsic biophysical properties contribute to the threshold dynamics in Type I and Type II neurons, which could decipher their significant functions in neural coding. PMID:26083350

  19. Survey of group I and group II introns in 29 sequenced genomes of the Bacillus cereus group: insights into their spread and evolution

    PubMed Central

    Tourasse, Nicolas J.; Kolstø, Anne-Brit

    2008-01-01

    Group I and group II introns are different catalytic self-splicing and mobile RNA elements that contribute to genome dynamics. In this study, we have analyzed their distribution and evolution in 29 sequenced genomes from the Bacillus cereus group of bacteria. Introns were of different structural classes and evolutionary origins, and a large number of nearly identical elements are shared between multiple strains of different sources, suggesting recent lateral transfers and/or that introns are under a strong selection pressure. Altogether, 73 group I introns were identified, inserted in essential genes from the chromosome or newly described prophages, including the first elements found within phages in bacterial plasmids. Notably, bacteriophages are an important source for spreading group I introns between strains. Furthermore, 77 group II introns were found within a diverse set of chromosomal and plasmidic genes. Unusual findings include elements located within conserved DNA metabolism and repair genes and one intron inserted within a novel retroelement. Group II introns are mainly disseminated via plasmids and can subsequently invade the host genome, in particular by coupling mobility with host cell replication. This study reveals a very high diversity and variability of mobile introns in B. cereus group strains. PMID:18587153

  20. Hydrogen-bond vibrational and energetic dynamical properties in sI and sII clathrate hydrates and in ice Ih: Molecular dynamics insights.

    PubMed

    Chakraborty, Somendra Nath; English, Niall J

    2015-10-21

    Equilibrium molecular dynamics (MD) simulations have been performed on cubic (sI and sII) polymorphs of methane hydrate, and hexagonal ice (ice Ih), to study the dynamical properties of hydrogen-bond vibrations and hydrogen-bond self-energy. It was found that hydrogen-bond energies are greatest in magnitude in sI hydrates, followed by sII, and their energies are least in magnitude in ice Ih. This is consistent with recent MD-based findings on thermal conductivities for these various materials [N. J. English and J. S. Tse, Phys. Rev. Lett. 103, 015901 (2009)], in which the lower thermal conductivity of sI methane hydrate was rationalised in terms of more strained hydrogen-bond arrangements. Further, modes for vibration and energy-transfer via hydrogen bonds in sI hydrate were found to occur at higher frequencies vis-à-vis ice Ih and sII hydrate in both the water-librational and OH⋯H regions because of the more strained nature of hydrogen bonds therein.

  1. Hydrogen-bond vibrational and energetic dynamical properties in sI and sII clathrate hydrates and in ice Ih: Molecular dynamics insights

    NASA Astrophysics Data System (ADS)

    Chakraborty, Somendra Nath; English, Niall J.

    2015-10-01

    Equilibrium molecular dynamics (MD) simulations have been performed on cubic (sI and sII) polymorphs of methane hydrate, and hexagonal ice (ice Ih), to study the dynamical properties of hydrogen-bond vibrations and hydrogen-bond self-energy. It was found that hydrogen-bond energies are greatest in magnitude in sI hydrates, followed by sII, and their energies are least in magnitude in ice Ih. This is consistent with recent MD-based findings on thermal conductivities for these various materials [N. J. English and J. S. Tse, Phys. Rev. Lett. 103, 015901 (2009)], in which the lower thermal conductivity of sI methane hydrate was rationalised in terms of more strained hydrogen-bond arrangements. Further, modes for vibration and energy-transfer via hydrogen bonds in sI hydrate were found to occur at higher frequencies vis-à-vis ice Ih and sII hydrate in both the water-librational and OH⋯H regions because of the more strained nature of hydrogen bonds therein.

  2. A phenoxo-bridged dicopper(ii) complex as a model for phosphatase activity: mechanistic insights from a combined experimental and computational study.

    PubMed

    Barman, Suman K; Mondal, Totan; Koley, Debasis; Lloret, Francesc; Mukherjee, Rabindranath

    2017-03-21

    A μ-phenoxo-bis(μ2-1,3-acetato)-bridged dicopper(ii) complex [Cu(L(1))(μ-O2CMe)2][NO3] (1) has been synthesized from the perspective of modeling phosphodiesterase activity. Structural characterization was done initially with 1·3Et2O (vapour diffusion of Et2O into MeOH solution of 1; poor crystal quality) and finally with its perchlorate salt [Cu(L(1))(μ-O2CMe)2][ClO4]·1.375MeCN·0.25H2O, crystallized from vapour diffusion of n-pentane into a MeCN-MeOH mixture (comparatively better crystal quality). An asymmetric unit of such a crystal contains two independent molecules of compositions [Cu(L(1))(μ-O2CMe)2][ClO4] and [Cu(L(1))(μ-O2CMe)2(MeCN)][ClO4] (coordinated MeCN with 0.75 occupancy), and two molecules of MeCN and H2O (each H2O molecule with 0.25 occupancy) as the solvent of crystallization. These two cations, each having five-coordinate (μ-phenoxo)bis(μ-acetato)-bridged Cu(II) ions, differ by only the coordination environment of only one Cu(II) ion, which has a weakly coordinated acetonitrile molecule in its sixth position. Temperature-dependent magnetic studies on 1 reveal that the copper(ii) centres are antiferromagnetically coupled with the exchange-coupling constant J = -124(1) cm(-1). Theoretically calculated J = -126.51 cm(-1), employing a broken-symmetry DFT approach, is in excellent agreement with the experimental value. The dicopper(ii) complex has been found to be catalytically efficient in the hydrolysis of 2-hydroxypropyl-p-nitrophenylphosphate (HPNP). Detailed kinetic experiments and solution studies (potentiometry, species distribution and ESI-MS) were performed to elucidate the reaction mechanism. DFT calculations were performed to discriminate between different possible mechanistic pathways. The free-energy barrier for HPNP hydrolysis catalyzed by 1 is comparable to that obtained from the experimentally-determined value. The involvement of non-covalent (hydrogen-bonding) interaction has also been probed by DFT calculations. The activity

  3. New Insights into the Au(I)···Pb(II) Closed-Shell Interaction: Tuning of the Emissive Properties with the Intermetallic Distance.

    PubMed

    Echeverría, Raquel; López-de-Luzuriaga, José M; Monge, Miguel; Moreno, Sonia; Olmos, M Elena

    2016-10-05

    Reaction of [Au2Ag2R4(Et2O)2] (R = C6Cl2F3(-) or C6F5(-)) with [Pb{HB(pz)3}]Cl in a 1:2 molar ratio led to complexes [AuPb{HB(pz)3}R2] (R = C6Cl2F3(-) (2) or C6F5(-) (3)) through transmetalation reactions. The crystal structures of these complexes display unsupported Au(I)···Pb(II) interactions of 3.0954(4) (2) and 3.2778(4) (3) Å, together with one (2) or two (3) F···Pb weak contacts. These intermetallic distances are compared to the shortest one found for the previously reported complex [Pb{HB(pz)3}Au(C6Cl5)2] (1) of 3.0494(4) (1) Å, showing a clear dependence with the donating properties of the different aurate units. The complexes are emissive in the solid state due to charge transfer transitions associated with the presence of Au(I)···Pb(II) interactions, in which the intermetallic distance plays a crucial role. Density functional theory and time-dependent density functional theory calculations support the assignment of the luminescent properties of the complexes. Ab initio Hartree-Fock and MP2 calculations on model systems of complexes 2 and 3 show the presence of strong Au(I)···Pb(II) closed-shell interactions of an ionic plus dispersive nature together with weak F···Pb contacts of a dispersive origin in the case of complexes 2 and 3.

  4. Enantioselective Pd(II)-catalyzed aerobic oxidative amidation of alkenes and insights into the role of electronic asymmetry in pyridine-oxazoline ligands.

    PubMed

    McDonald, Richard I; White, Paul B; Weinstein, Adam B; Tam, Chun Pong; Stahl, Shannon S

    2011-06-03

    Enantioselective intramolecular oxidative amidation of alkenes has been achieved using a (pyrox)Pd(II)(TFA)(2) catalyst (pyrox = pyridine-oxazoline, TFA = trifluoroacetate) and O(2) as the sole stoichiometric oxidant. The reactions proceed at room temperature in good-to-excellent yields (58-98%) and with high enantioselectivity (ee = 92-98%). Catalyst-controlled stereoselective cyclization reactions are demonstrated for a number of chiral substrates. DFT calculations suggest that the electronic asymmetry of the pyrox ligand synergizes with steric asymmetry to control the stereochemical outcome of the key amidopalladation step.

  5. Generation, Characterization, and Reactivity of a Cu(II)-Alkylperoxide/Anilino Radical Complex: Insight into the O-O Bond Cleavage Mechanism.

    PubMed

    Paria, Sayantan; Ohta, Takehiro; Morimoto, Yuma; Ogura, Takashi; Sugimoto, Hideki; Fujieda, Nobutaka; Goto, Kei; Asano, Kaori; Suzuki, Takeyuki; Itoh, Shinobu

    2015-09-02

    The reaction of [Cu(I)(TIPT3tren) (CH3CN)]ClO4 (1) and cumene hydroperoxide (C6H5C(CH3)2OOH, ROOH) at -60 °C in CH2Cl2 gave a Cu(II)-alkylperoxide/anilino radical complex 2, the formation of which was confirmed by UV-vis, resonance Raman, EPR, and CSI-mass spectroscopy. The mechanism of formation of 2, as well as its reactivity, has been explored.

  6. Enantioselective Pd(II)-Catalyzed Aerobic Oxidative Amidation of Alkenes and Insights into the Role of Electronic Asymmetry in Pyridine-Oxazoline Ligands

    PubMed Central

    McDonald, Richard I.; White, Paul B.; Weinstein, Adam B.; Tam, Chun Pong; Stahl, Shannon S.

    2011-01-01

    Enantioselective intramolecular oxidative amidation of alkenes has been achieved using a (pyrox)Pd(II)(TFA)2 catalyst (pyrox = pyridine-oxazoline, TFA = trifluoroacetate) and O2 as the sole stoichiometric oxidant. The reactions proceed at room temperature in good-to-excellent yield (58-98%) and with high enantioselectivity (ee = 92-98%). Catalyst-controlled stereoselective cyclization reactions are demonstrated for a number of chiral substrates. DFT calculations suggest that the electronic asymmetry of the pyrox ligand synergizes with steric asymmetry to control the stereochemical outcome of the key amidopalladation step. PMID:21534607

  7. S3 State of the O2-Evolving Complex of Photosystem II: Insights from QM/MM, EXAFS, and Femtosecond X-ray Diffraction.

    PubMed

    Askerka, Mikhail; Wang, Jimin; Vinyard, David J; Brudvig, Gary W; Batista, Victor S

    2016-02-23

    The oxygen-evolving complex (OEC) of photosystem II has been studied in the S3 state by electron paramagnetic resonance, extended X-ray absorption fine structure (EXAFS), and femtosecond X-ray diffraction (XRD). However, the actual structure of the OEC in the S3 state has yet to be established. Here, we apply hybrid quantum mechanics/molecular mechanics methods and propose a structural model that is consistent with EXAFS and XRD. The model supports binding of water ligands to the cluster in the S2 → S3 transition through a carousel rearrangement around Mn4, inspired by studies of ammonia binding.

  8. Synthesis and characterization of Fe(II) β-diketonato complexes with relevance to acetylacetone dioxygenase: insights into the electronic properties of the 3-histidine facial triad.

    PubMed

    Park, Heaweon; Baus, Jacob S; Lindeman, Sergey V; Fiedler, Adam T

    2011-12-05

    A series of high-spin iron(II) β-diketonato complexes have been prepared and characterized with the intent of modeling the substrate-bound form of the enzyme acetylacetone dioxygenase (Dke1). The Dke1 active site features an Fe(II) center coordinated by three histidine residues in a facial geometry--a departure from the standard 2-histidine-1-carboxylate (2H1C) facial triad dominant among nonheme monoiron enzymes. The deprotonated β-diketone substrate binds to the Fe center in a bidentate fashion. To better understand the implications of subtle changes in coordination environment for the electronic structures of nonheme Fe active sites, synthetic models were prepared with three different supporting ligands (L(N3)): the anionic (Me2)Tp and (Ph2)Tp ligands ((R2)Tp = hydrotris(pyrazol-1-yl)borate substituted with R-groups at the 3- and 5-pyrazole positions) and the neutral (Ph)TIP ligand ((Ph)TIP = tris(2-phenylimidazol-4-yl)phosphine). The resulting [(L(N3))Fe(acac(X))](0/+) complexes (acac(X) = substituted β-diketonates) were analyzed with a combination of experimental and computational methods, namely, X-ray crystallography, cyclic voltammetry, spectroscopic techniques (UV-vis absorption and (1)H NMR), and density functional theory (DFT). X-ray diffraction results for complexes with the (Me2)Tp ligand revealed six-coordinate Fe(II) centers with a bound MeCN molecule, while structures of the (Ph2)Tp and (Ph)TIP complexes generally exhibited five-coordinate geometries. Each [(L(N3))Fe(acac(X))](0/+) complex displays two broad absorption features in the visible region that arise from Fe(II)→acac(X) charge transfer and acac(X)-based transitions, consistent with UV-vis data reported for Dke1. These absorption bands, along with the Fe redox potentials, are highly sensitive to the identity of L(N3) and substitution of the β-diketonates. By interpreting the experimental results in conjunction with DFT calculations, detailed electronic-structure descriptions of the

  9. Mesozoic intracontinental underthrust in the SE margin of the North China Block: Insights from the Xu-Huai thrust-and-fold belt

    NASA Astrophysics Data System (ADS)

    Shu, Liangshu; Yin, Hongwei; Faure, Michel; Chen, Yan

    2017-06-01

    The Xu-Huai thrust-and-fold belt, located in the southeastern margin of the North China Block, consists mainly of thrust and folded pre-Mesozoic strata. Its geodynamic evolution and tectonic setting are topics of long debate. This paper provides new evidence from geological mapping, structural analysis, and making balance cross-sections, with restoration of cross-sections. Results suggest that this belt was subjected to two-phase deformation, including an early-phase regional-scale NW-ward thrust and fold, and a late-phase extension followed by the emplacement of dioritic, monzodioritic porphyrites dated at 131-135 Ma and locally strike-slip shearing. According to the mapping, field observations and drill-hole data, three structural units were distinguished, namely, (1) the pre-Neoproterozoic crystalline basement in the eastern segment, (2) the nappe unit or the thrust-and-fold zone in the central segment, which is composed of Neoproterozoic to Ordovician carbonate rocks and Carboniferous-Permian coal-bearing rocks, about 2600 m thick, and (3) the western frontal zone. A major decollement fault has also been identified in the base of the nappe unit, on which dozen-meter to km-scale thrust-and-fold bodies were commonly developed. All pre-Mesozoic depositional sequences were involved into a widespread thrust and fold event. Six uncompetent-rock layers with biostratigraphic ages (Nanjing University, 1996) have been recognized, and each uncompetent-rock layer occurred mainly in the top of the footwall, playing an important role in the development of the Xu-Huai thrust-and-fold belt. Geometry of the major decollement fault suggests that the nappe unit of this belt was rooted in its eastern side, near the Tan-Lu Fault Zone. Two geological cross-sections were chosen for structural balancing and restoration. From the balanced cross-sections, ramp-flat and imbricated faults as well as fault-related folds were identified. A shortening of 20.6-29.6 km was obtained from

  10. Control of Lunar and Martian DustExperimental Insights from Artificial and Natural Cyanobacterial and Algal Crusts in the Desert of Inner Mongolia, China

    NASA Astrophysics Data System (ADS)

    Liu, Yongding; Cockell, Charles S.; Wang, Gaohong; Hu, Chunxiang; Chen, Lanzhou; De Philippis, Roberto

    2008-02-01

    Studies on the colonization of environmentally extreme ground surfaces were conducted in a Mars-like desert area of Inner Mongolia, People's Republic of China, with microalgae and cyanobacteria. We collected and mass-cultured cyanobacterial strains from these regions and investigated their ability to form desert crusts artificially. These crusts had the capacity to resist sand wind erosion after just 15 days of growth. Similar to the surface of some Chinese deserts, the surface of Mars is characterized by a layer of fine dust, which will challenge future human exploration activities, particularly in confined spaces that will include greenhouses and habitats. We discuss the use of such crusts for the local control of desert sands in enclosed spaces on Mars. These experiments suggest innovative new directions in the applied use of microbe-mineral interactions to advance the human exploration and settlement of space.

  11. Control of Lunar and Martian dust--experimental insights from artificial and natural cyanobacterial and algal crusts in the desert of Inner Mongolia, China.

    PubMed

    Liu, Yongding; Cockell, Charles S; Wang, Gaohong; Hu, Chunxiang; Chen, Lanzhou; De Philippis, Roberto

    2008-02-01

    Studies on the colonization of environmentally extreme ground surfaces were conducted in a Mars-like desert area of Inner Mongolia, People's Republic of China, with microalgae and cyanobacteria. We collected and mass-cultured cyanobacterial strains from these regions and investigated their ability to form desert crusts artificially. These crusts had the capacity to resist sand wind erosion after just 15 days of growth. Similar to the surface of some Chinese deserts, the surface of Mars is characterized by a layer of fine dust, which will challenge future human exploration activities, particularly in confined spaces that will include greenhouses and habitats. We discuss the use of such crusts for the local control of desert sands in enclosed spaces on Mars. These experiments suggest innovative new directions in the applied use of microbe-mineral interactions to advance the human exploration and settlement of space.

  12. An advanced, new long-legged bird from the Early Cretaceous of the Jehol Group (northeastern China): insights into the temporal divergence of modern birds.

    PubMed

    Liu, Di; Chiappe, Luis M; Zhang, Yuguang; Bell, Alyssa; Meng, Qingjin; Ji, Qiang; Wang, Xuri

    2014-11-14

    We describe a new ornithuromorph bird species, Gansus zheni from the Lower Cretaceous lacustrine deposits of the Jiufotang Formation (Jehol Group), Liaoning Province, China. A cladistic analysis resolves Gansus zheni as the sister taxon of the roughly contemporaneous Gansus yumenensis (Xiagou Formation, Gansu Province), and together as the most immediate outgroup to Ornithurae. Gansus zheni is the most advanced bird known today for the Jehol Biota. Its discovery provides the best-documented case of inter-basinal correlations (Jehol and Changma basins of Liaoning and Gansu provinces, respectively) using low-taxonomic clades of fossil birds. The existence of close relatives of Ornithurae in deposits formed at about 120 million years ago helps to mitigate the long-standing controversy between molecular and paleontological evidence for the temporal divergence of modern birds (Neornithes).

  13. Intraplate earthquakes and their link with mantle dynamics: Insights from P-wave teleseismic tomography along the northern part of the North-South Tectonic Zone in China

    NASA Astrophysics Data System (ADS)

    He, Chuansong; Santosh, M.

    2017-05-01

    The North-South Tectonic Zone (NSTZ) running across the Chinese continent is an important earthquake-prone zone. Around one third of the strong earthquakes (> 7.0) of China in the past occurred in this region. Receiver function study has imaged vertical convection in the mantle beneath the northern part of the NSTZ (NNSTZ), which might be related to stress accumulation and release as well as related earthquakes. Here we perform a P-wave teleseismic tomographic analysis of this region. Our results reveal prominent low-velocity and high-velocity perturbations in the upper mantle beneath this region, which we correlate with mantle upwelling, possibly resulting from lower crustal and (or) lithospheric delamination. Our results also reveal significant contrast in the velocity perturbation of the lithosphere along the two sides of this tectonic zone, suggesting possible material exchange between the eastern and western domains and lithosphere-scale control on the generation of earthquakes.

  14. Spatial epidemiology in zoonotic parasitic diseases: insights gained at the 1st International Symposium on Geospatial Health in Lijiang, China, 2007

    PubMed Central

    Zhou, Xiao-Nong; Lv, Shan; Yang, Guo-Jing; Kristensen, Thomas K; Bergquist, N Robert; Utzinger, Jürg; Malone, John B

    2009-01-01

    The 1st International Symposium on Geospatial Health was convened in Lijiang, Yunnan province, People's Republic of China from 8 to 9 September, 2007. The objective was to review progress made with the application of spatial techniques on zoonotic parasitic diseases, particularly in Southeast Asia. The symposium featured 71 presentations covering soil-transmitted and water-borne helminth infections, as well as arthropod-borne diseases such as leishmaniasis, malaria and lymphatic filariasis. The work made public at this occasion is briefly summarized here to highlight the advances made and to put forth research priorities in this area. Approaches such as geographical information systems (GIS), global positioning systems (GPS) and remote sensing (RS), including spatial statistics, web-based GIS and map visualization of field investigations, figured prominently in the presentation. PMID:19193214

  15. Spatiotemporal reconstruction of Late Mesozoic silicic large igneous province and related epithermal mineralization in South China: Insights from the Zhilingtou volcanic-intrusive complex

    NASA Astrophysics Data System (ADS)

    Wang, Guo-Guang; Ni, Pei; Zhao, Chao; Wang, Xiao-Lei; Li, Pengfei; Chen, Hui; Zhu, An-Dong; Li, Li

    2016-11-01

    Silicic large igneous provinces (SLIPs) generally reflect large-scale melting of lower crustal materials and represent significant metal reservoirs. The South China Block-Coastal Region (SCB-CR) SLIP hosts several large epithermal deposits. To better understand these deposits, we document the spatiotemporal framework of the host SLIP across the SCB-CR. Using zircon U-Pb dating and geochemical and isotopic analysis, we identify four stages of emplacement. Stage 1 felsophyre (circa 149 Ma) shows a chemical affinity to highly fractionated I-type granites. Stages 2 and 3 of low-Mg felsic volcanics (circa 128 to 111 Ma) and stage 4 felsite (circa 100 Ma) have higher ɛHf(t) and ɛNd(t) values than stage 1 felsophyre, suggesting a significant contribution of newly underplated juvenile crust to the magma sources. Stage 4 diabase (circa 101 Ma) was likely produced by melting of subduction˗metasomatized asthenospheric mantle. Together with reliable published data, we build a new spatiotemporal framework of volcanics and infer that the majority of the SCB-CR SLIP was related to the gradual northwestward subduction of the Izanagi plate beneath South China in a continental arc setting during circa 170 to 110 Ma, and minor contribution was from the eastward retreat of the subducting slab in a back-arc setting during circa 110 to 90 Ma. We conclude that the large-scale epithermal mineralization was generated by melting of the metal-rich, thin (30-40 km), newly underplated hydrous juvenile crust during the tectonic transition from arc to back-arc settings.

  16. Geometry and emplacement of the Late Cretaceous mafic dyke swarms on the islands in Zhejiang Province, Southeast China: Insights from high-resolution satellite images

    NASA Astrophysics Data System (ADS)

    Chen, Ning-hua; Dong, Jin-jin; Chen, Jian-yu; Dong, Chuan-wan; Shen, Zhong-yue

    2014-01-01

    The geology of Zhejiang coastal area in Southeast China is characterized by numerous Late Mesozoic intrusive rocks and widespread mafic dyke swarms, which indicate continental lithospheric extensional events during the Jurassic and Cretaceous. This work is focused on using multisource high-resolution remote sensing images (Worldview2, Geoeye1 and Quickbird2) to identify the geometry, morphology and location of previously undocumented and poorly understood dyke swarms exposed on the islands in Zhejiang Province. The geometry of each dyke is described by its strike, length and thickness. The spatial distribution of the dyke density and crustal dilation are obtained based on the statistics of 774 extracted mafic dykes. Field surveys are performed in some islands in order to analyze the detailed geometric features and assess the interpretative accuracy. The spectral measurement and analysis of mafic dykes are performed as well for remote sensing imagery processing and lithological interpretation. The results show that the frequency distributions of the length and thickness of dykes follow power law curves. The maximum and mean dyke thicknesses are 11.2 m and 1.43 m, respectively. The crustal dilation of the islands ranges from 0.09% to 7.4%. From the north to the south islands, the dilation decreases gradually. The dyke frequency and density have the same distribution as the dilation. According to 40Ar-39Ar age (Zhongshanjie archipelago) and U-Pb zircon age (Sijiao Island) of the mafic dyke, the dyke swarms on the eastern Zhejiang islands emplaced at around 87-97 Ma. The cross-cutting relationships of dykes and host rocks show that the mafic dyke swarms have close spatial correlations with granite. The dykes stretch in various directions whereas the NE-trending dykes dominate. Our research reveals four intrusive events that imply the crustal extension and intermittent variation of the regional stress field in the coastal area of southeastern China in the Late

  17. Insights into the photoprotective switch of the major light-harvesting complex II (LHCII): a preserved core of arginine-glutamate interlocked helices complemented by adjustable loops.

    PubMed

    Sunku, Kiran; de Groot, Huub J M; Pandit, Anjali

    2013-07-05

    Light-harvesting antennae of the LHC family form transmembrane three-helix bundles of which two helices are interlocked by conserved arginine-glutamate (Arg-Glu) ion pairs that form ligation sites for chlorophylls. The antenna proteins of photosystem II have an intriguing dual function. In excess light, they can switch their conformation from a light-harvesting into a photoprotective state, in which the excess and harmful excitation energies are safely dissipated as heat. Here we applied magic angle spinning NMR and selective Arg isotope enrichment as a noninvasive method to analyze the Arg structures of the major light-harvesting complex II (LHCII). The conformations of the Arg residues that interlock helix A and B appear to be preserved in the light-harvesting and photoprotective state. Several Arg residues have very downfield-shifted proton NMR responses, indicating that they stabilize the complex by strong hydrogen bonds. For the Arg Cα chemical shifts, differences are observed between LHCII in the active, light-harvesting and in the photoprotective, quenched state. These differences are attributed to a conformational change of the Arg residue in the stromal loop region. We conclude that the interlocked helices of LHCII form a rigid core. Consequently, the LHCII conformational switch does not involve changes in A/B helix tilting but likely involves rearrangements of the loops and helical segments close to the stromal and lumenal ends.

  18. Computational insights on crystal structures of the oxygen-evolving complex of photosystem II with either Ca(2+) or Ca(2+) substituted by Sr(2+).

    PubMed

    Vogt, Leslie; Ertem, Mehmed Z; Pal, Rhitankar; Brudvig, Gary W; Batista, Victor S

    2015-01-27

    The oxygen-evolving complex of photosystem II can function with either Ca(2+) or Sr(2+) as the heterocation, but the reason for different turnover rates remains unresolved despite reported X-ray crystal structures for both forms. Using quantum mechanics/molecular mechanics (QM/MM) calculations, we optimize structures with each cation in both the resting state (S1) and in a series of reduced states (S0, S-1, and S-2). Through comparison with experimental data, we determine that the X-ray crystal structures with either Ca(2+) or Sr(2+) are most consistent with the S-2 state (i.e., Mn4[III,III,III,II] with O4 and O5 protonated). As expected, the QM/MM models show that Ca(2+)/Sr(2+) substitution results in the elongation of the heterocation bonds and the displacement of terminal waters W3 and W4. The optimized structures also show that hydrogen-bonded W5 is displaced in all S states with Sr(2+) as the heterocation, suggesting that this water may play a critical role during water oxidation.

  19. Structural insights into the light-driven auto-assembly process of the water-oxidizing Mn4CaO5-cluster in photosystem II

    PubMed Central

    Zhang, Miao; Bommer, Martin; Chatterjee, Ruchira; Hussein, Rana; Yano, Junko; Dau, Holger; Kern, Jan; Dobbek, Holger; Zouni, Athina

    2017-01-01

    In plants, algae and cyanobacteria, Photosystem II (PSII) catalyzes the light-driven splitting of water at a protein-bound Mn4CaO5-cluster, the water-oxidizing complex (WOC). In the photosynthetic organisms, the light-driven formation of the WOC from dissolved metal ions is a key process because it is essential in both initial activation and continuous repair of PSII. Structural information is required for understanding of this chaperone-free metal-cluster assembly. For the first time, we obtained a structure of PSII from Thermosynechococcus elongatus without the Mn4CaO5-cluster. Surprisingly, cluster-removal leaves the positions of all coordinating amino acid residues and most nearby water molecules largely unaffected, resulting in a pre-organized ligand shell for kinetically competent and error-free photo-assembly of the Mn4CaO5-cluster. First experiments initiating (i) partial disassembly and (ii) partial re-assembly after complete depletion of the Mn4CaO5-cluster agree with a specific bi-manganese cluster, likely a di-µ-oxo bridged pair of Mn(III) ions, as an assembly intermediate. DOI: http://dx.doi.org/10.7554/eLife.26933.001 PMID:28718766

  20. Recognition of RNA Polymerase II and Transcription Bubbles by XPG,CSB and TFIIH: Insights for Transcription-Coupled Repair and CockayneSyndrome

    SciTech Connect

    Sarker, Altaf H.; Tsutakawa, Susan E.; Kostek, Seth; Ng, Cliff; Shin, David S.; Peris, Marian; Campeau, Eric; Tainer, John A.; Nogales,Eva; Cooper, Priscilla K.

    2005-10-21

    Loss of a non-enzymatic function of XPG results in defective transcription-coupled repair (TCR), Cockayne syndrome (CS) and early death, but the molecular basis for these phenotypes is unknown. Mutation of CSB, CSA, or the TFIIH helicases XPB and XPD can also cause defective TCR and CS. We show that XPG interacts with elongating RNA polymerase II(RNAPII) in the cell and binds stalled RNAPII ternary complexes in vitro both independently and cooperatively with CSB. XPG binds transcription-sized DNA bubbles through two domains not required for incision and functionally interacts with CSB on these bubbles to stimulate its ATPase activity. Bound RNAPII blocks bubble incision by XPG, but an ATP hydrolysis-dependent process involving TFIIH creates access to the junction, allowing incision. Together, these results implicate coordinated recognition of stalled transcription by XPG and CSB in TCR initiation and suggest that TFIIH-dependent remodeling of stalled RNAPII without release may be sufficient to allow repair.

  1. Insights into anticancer activity and mechanism of action of a ruthenium(II) complex in human esophageal squamous carcinoma EC109 cells.

    PubMed

    Guo, Liubin; Lv, Gaochao; Qiu, Ling; Yang, Hui; Zhang, Li; Yu, Huixin; Zou, Meifen; Lin, Jianguo

    2016-09-05

    A ruthenium(II) complex [Ru(p-cymene)(NHC)Cl2] (NHC=1,3-bis(4-(tert-butyl)benzylimidazol-2-ylidene), referred to as L-4, has been designed and synthesized recently in order to look for new anticancer drugs with high efficacy and low side effects. The anticancer activity and mechanism of action of L-4 in human esophageal squamous carcinoma EC109 cells were systematically investigated. The results revealed that L-4 exerted strong inhibitory effect on the proliferation of EC109 cells, and it arrested EC109 cells at G2/M phase, accompanied with the up-regulation of p53 and p21 and the down-regulation of cyclin D1. The results also showed that the reactive oxygen species (ROS)-dependent apoptosis of EC109 can be induced by L-4 via inhibiting the activity of glutathione reductase (GR), decreasing the ratio of glutathione to oxidized glutathione (GSH/GSSG), and leading to the generation of reactive oxygen species. The mitochondria-mediated apoptosis of EC109 induced by L-4 was also observed from the increase of Bax/Bcl-2 ratio, overload of Ca(2+), disruption of mitochondrial membrane potential (MMP), redistribution of cytochrome c, and activation of caspase-3/-9. However, the effects of L-4 on the cell viability, GR activity, GSH/GSSG ratio, reactive oxygen species level, mitochondria dysfunction and apoptosis induction were remarkably attenuated by adding the reactive oxygen species scavenger, NAC. Therefore, it was concluded that L-4 can inhibit the proliferation of EC109 cells via blocking cell cycle progression and inducing reactive oxygen species-dependent and mitochondria-mediated apoptosis. These findings suggested that the ruthenium(II) complex might be a potential effective chemotherapeutic agent for human esophageal squamous carcinoma (ESCC) and worthy of further investigation. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Insights into the dynamics of planetary interiors obtained through the study of global distribution of volcanoes II: Tectonic implications from Venus

    NASA Astrophysics Data System (ADS)

    Cañon-Tapia, Edgardo

    2014-06-01

    The distribution of volcanic features is ultimately controlled by processes taking place beneath the surface of a planet. For this reason, characterization of volcano distribution at a global scale can be used to obtain insights concerning dynamic aspects of planetary interiors. Until present, studies of this type commonly have focused on volcanic features of a specific type (e.g., large volcanoes in Venus or hot-spot volcanism on Earth), or have concentrated on relatively small regions (i.e., vent distribution within individual volcanic fields), but no comparison of extensive databases has been made by using the same tools in both planets. In this work, the description of the distribution of volcanic features observed over the entire surface of Venus is made using the same tool used for Earth, and is applied to an extensive database. The analysis is based on density contours obtained with the Fisher kernel. As a result, several groupings of volcanoes are identified refining the already documented concentration of volcanoes on the BAT zone. In particular some doughnut-like patterns are observed that might be related to the action of mantle plumes. The occurrence of such features on Earth, as well as the existence of a uniform distribution of background volcanism on both planets, suggests similarities on their geodynamic behavior that had not been identified previously.

  3. Tectonic uplift-influenced monsoonal changes promoted hominin occupation of the Luonan Basin: Insights from a loess-paleosol sequence, eastern Qinling Mountains, central China

    NASA Astrophysics Data System (ADS)

    Fang, Qian; Hong, Hanlie; Zhao, Lulu; Furnes, Harald; Lu, Huayu; Han, Wen; Liu, Yao; Jia, Zhuoyue; Wang, Chaowen; Yin, Ke; Algeo, Thomas J.

    2017-08-01

    Quaternary soil deposits from northern and southern China are distinctly different, reflecting variability of the East Asian monsoon north and south of the Qinling Mountains. Coeval sediments from the transitional climatic zone of central China, which are little studied to date, have the potential to improve our understanding of Quaternary monsoon changes and associated influences on hominin occupation of this region. Here, we investigate in detail a well-preserved and continuous Quaternary loess-paleosol sequence (Shangbaichuan) from the Luonan Basin, using a variety of weathering indices including major and trace element ratios, clay mineralogy, and Fe-oxide mineralogy. The whole-rock samples display similar rare earth element patterns characterized by upper continental crustal ratios: (La/Yb)N ≈ 9.5 and Eu/Eu* ≈ 0.65. Elemental data such as (La/Yb)N, La/Th and Eu/Eu* ratios show a high degree of homogeneity, suggesting that dust in the source region may have been thoroughly mixed and recycled, resulting in all samples having a uniform initial composition. Indices for pedogenic weathering such as Na/K, Ba/Sr, Rb/Sr, CIA, CIW, CPA, PIA, kaolinite/illite, (kaolinite + smectite)/illite, and hematite/(hematite + goethite) exhibit similar secular trends and reveal a four-stage accumulation history. The indices also indicate that the climate was warmer and wetter during the most recent interglacial stage, compared with coeval environments of the Chinese Loess Plateau. Secular changes in weathering intensity can be related to stepwise uplift of the Qinling Mountains and variation in East Asian monsoon intensity, both of which played significant roles in controlling climate evolution in the Luonan Basin. Furthermore, intensified aridity and winter monsoon strength in dust source areas, as evidenced by mineralogic and geochemical changes, may have been due to the mid-Pleistocene climate transition. Based on temporal correlation of warmer and wetter climatic conditions

  4. Characteristics of gas hydrate-bearing sediments of the northern South China Sea: insight into past hydrate episodic dissociations and intensities of seepage

    NASA Astrophysics Data System (ADS)

    Chen, F.; Su, X.; Zhou, Y.; Zhang, G.; Zhuang, C.; Lu, H.

    2016-12-01

    In 2013 the second China's major gas hydrate expedition, GMGS2, cored and recovered abundant gas hydrates at five sites, which were located in the South China Sea.Site GMGS08 (95m long) contained two gas hydrate intervals and five authigenic carbonate intervals. We analyzed carbon and oxygen isotopes of authigenic carbonates and foraminifera shells in sediments recovered at this site, in order to understanding of features of hydrate-bearing sediments and timing of gas hydrate dissociation and methane seepage at this site. An age of younger than 0.27 Ma was estimated for the 95 m sedimentary sequences at Site GMGS08. A detailed age model was further established by employing of U/Th and AMS14C dating of authigenic carbonates and seep bivalve fragments. These carbonates are featured by 13C-depleted (with a range from -38.9‰ to 56.7‰ δ13C) and positive δ18O (from 2.94‰ to 5.66‰ δ18O) values. A further analysis indicated the formation of carbonates were correlated to methane seepages derived from gas hydrate dissociation. Subsequently, these five authigenic carbonates intervals were seen as five hydrate episodic dissociation events since last 0.27Ma at this site. The most significant event during the period of 0.11 Ma to 0.13 Ma were account for the formation of thick authigenic carbonate (with the lowest -56.8‰ δ13C value) platform on paleo-seafloor at this site. The upmost authigenic carbonates interval is just overlying on the top of the upper gas hydrate occurrence zone, and it represents the latest methane seepage event with an age of 26ka to 36ka. Well correlated to these five events, it existed five intervals with strongly 13C-depleted carbon (-15.85‰ PDB) of foraminifera shells both from benthic and planktonic. The anomalous δ13C depletion records of planktonic G. ruber shells should be caused by formation of secondary authigenic carbonates on the shells, which were derived from the anaerobic oxidation of methane (AOM). The analyses on carbonate

  5. The Geochemical Evolution of the Granitoid Rocks in the South Qinling Belt: Insights from the Petrogenesis of Dongjiangkou and Zhashui intrusions, Central China

    NASA Astrophysics Data System (ADS)

    Hu, F.; Liu, S.; Ducea, M. N.; Zhang, W.; Deng, Z.

    2016-12-01

    The Late Triassic granitoids in the South Qinling Belt (SQB) are excellent subjects to study the geochemical evolution during the collision between the North China Craton and South China Block. This study shows new obtained geological and geochemical data of the Dongjiangkou and Zhashui intrusions and compiles published geochemical data of granitoids, revealing that the Dongjiangkou intrusion consists of ca. 223-214 Ma granitoids with abundant coeval mafic magmatic enclaves (MMEs), and the Zhashui intrusion consists of ca. 203-197 Ma granites which resemble with rare MMEs. The MMEs are characterized by low SiO2 and Sr/Y , but high MgO, K2O and Rb contents, with ɛHf(t) of -0.8 to +4.3, suggesting they are formed by partial melting of the phlogopite-bearing metasomatized lithospheric mantle. The Dongjiangkou granitoids are characterized by medium to high SiO2, and high K2O, MgO and Rb, with ɛHf(t) of -18.1 to -0.4. Together with geochemical modeling, we suggest that the Dongjiangkou granitoids are formed by magma mixing between 70-90% melts derived from the Neoproterozoic juvenile basements and 10-30% MME melts. The Zhashui granitoid rocks exhibit high SiO2, K2O, A/CNK values, with ɛHf(t) of -3.5 to +2.3, suggesting they are mainly formed by partial melting of the Neoproterozoic juvenile metamorphic greywackes. Based on the compiled geochemical data of granitoids in the SQB, a clear geochemical evolution is discovered between ca. 235 Ma and 190 Ma. A flare-up event is recognized during 225-205 Ma and the lower SiO2 and Sr/Y of the granitoids during this period indicate prominent involvement of mantle-derived melts during crustal melting. The granitoids with higher SiO2 and Sr/Y during 225-205 Ma, however, suggest they were formed under a greater pressure than previous period (235-225 Ma) granitoids, reflecting the crust may become thicker after syn-collisional process. Few granitoid intrusions were formed after 205 Ma, and they display high SiO2 with low Sr

  6. Insights on fault-valve behavior gained from the Ms5.1 isolated shallow earthquake in Moxi gas reservoir, Sichuan Basin, China

    NASA Astrophysics Data System (ADS)

    Lei, X.; Ma, S.; Wang, X.; Su, J.

    2015-12-01

    We investigated in detail the 2010 Ms5.1 (Mw4) Suining earthquake (a temporally and spatially isolated event) centered in Moxi gas field which is located in the tectonically stable central region of Sichuan Basin, China. The focal depth is estimated to be approximately 2.4 km and thus the earthquake is nucleated in Triassic marine sediment, coincident with the depths of the top boundary of Jialingjiang limestone formation (T1) which is an over-pressured (R~2.2) gas reservoir. The strike/dip/rake of source fault is 209/33/102, showing a rupture of a blind reverse fault in agree with the geological structures and regional stress regime of this area. Through an integrated analysis of several issues, including the focal parameters, the local petroleum geology and radon anomaly, and numerical stress analysis for gas production and injection, we propose that the associated fault slip of this earthquake was most probably initiated and driven by gas injection from the underlying over-pressured reservoir into the shallower gas reservoir of normal pressure. With consideration of the fact that the injection-induced seismicity in nearby gas fields shows very low levels of aftershock productivity, no aftershocks following the Suining earthquake indicates that the gas injection from the deeper reservoir is somewhat episodic and a fault-valve behavior.

  7. Authigenic carbonates from an active cold seep of the northern South China Sea: New insights into fluid sources and past seepage activity

    NASA Astrophysics Data System (ADS)

    Feng, Dong; Chen, Duofu

    2015-12-01

    Site F (also named Formosa ridge) represents the most vigorous cold seep on the northern South China Sea continental slope. In order to constrain the fluid sources and intensities of seepage, we investigated the petrography, mineralogy, stable carbon and oxygen isotopic compositions, element geochemistry and radiocarbon dating of authigenic carbonate rocks retrieved from the seafloor. Carbonate rocks mainly occurred as crusts, nodules, and nodular masses incorporated in carbonate breccias. The carbonates were comprised mainly of high-Mg calcite and aragonite. The δ13C of authigenic carbonate varied from -55.3‰ to -34.3‰ (mean: -48.5‰; n=47) vs. V-PDB, suggesting biogenic methane is the dominant carbon source fuelling the system. The δ18OCarbonate values were from +3.6‰ to +4.8‰ (mean: +3.9‰; n=47). The observed 18O-enrichement in relation to calculated equilibrium values in the carbonates probably reflects dissolution of gas hydrates. Combination of seafloor observations and the obtained AMS 14C ages suggest that (1) initiation of methane seepage from at least 10.6 ka ago; (2) environmental conditions may have been favorable for enhanced fluid seepage around 6 ka BP and (3) relatively low intensity of seepage from 2 ka BP till today.

  8. Kinetic processes for plastic deformation of olivine in the Poyi ultramafic intrusion, NW China: Insights from the textural analysis of a 1700 m fully cored succession

    NASA Astrophysics Data System (ADS)

    Yao, Zhuo-sen; Qin, Ke-zhang; Xue, Sheng-chao

    2017-07-01

    The ubiquitous presence of undulose extinction and subgrain boundaries in olivine crystals is commonly perceived as originating in the mantle, however these plastic deformation features are also well developed in the Poyi ultramafic intrusion, NW China. In this case, olivine was deformed through kinetic processes in a crustal magma chamber, rather than by deformation processes in the upper mantle. Moreover, accumulation and textural coarsening were critical to the characteristics of crystal size distributions (CSDs) of olivines in the Poyi intrusion. The axial deformational compaction of crystal mush was revealed by virtue of other quantitative textural analyses (e.g., spatial distribution patter, alignment factor and aspect ratio). Additionally, based on the contrast of density between crystal matrix and interstitial melt, adequate stress was generated by the km-scale crystal framework in Poyi body ( 2-11 MPa) which triggered the distortion of grain-lattice in olivine. The deformation mechanisms of olivine primarily are dislocation creep and dislocation-accommodated grain boundary sliding (DisGBS), while diffusion creep is subsidiary. This study has revealed various kinetic processes in a magmatic system by first demonstrating the genetic relationship between mineral deformation and axial compaction of crystal mush while highlighting the uncertainty of employing the deformation features of olivine in peridotite xenoliths as an indicator for a mantle origin. In contrast to the olivine populations of xenocrysts that underwent fragmentation during ascent, the deformed primitive olivines in compaction exhibit a distinct shortage of small grains, which is conducive to delimiting these two types of deformed grains.

  9. In situ, high-resolution DGT measurements of dissolved sulfide, iron and phosphorus in sediments of the East China Sea: Insights into phosphorus mobilization and microbial iron reduction.

    PubMed

    Ma, Wei-Wei; Zhu, Mao-Xu; Yang, Gui-Peng; Li, Tie

    2017-08-01

    Dissolved sulfide, iron (Fe), and phosphorus (P) concentrations in sediments of the East China Sea were simultaneously measured in situ by diffusive gradients in thin films (DGT) technique. The results, by combination with solid-phase Fe speciation, were used to characterize the interplays of Fe, S and P. Diverse distributions of dissolved sulfide among the sites are attributable to highly dynamic diagenetic regimes and varying availability of labile organic carbon (OC). The DGT technique provided high-resolution evidence for coexistence of microbial iron reduction (MIR) and sulfate reduction in localized zones, and for Fe-coupled P mobilization. Measured Fe(2+)/P ratios suggest that Fe(2+) reoxidatiion at the oxic zones can serve as an efficient scavenger of P. Empirical estimation indicates that MIR plays an important role in anaerobic OC mineralization in the sediments, which is a combined result of low availability of labile OC, high reactive Fe content, and unsteady diagenetic regimes. Copyright © 2017. Published by Elsevier Ltd.

  10. Polybrominated diphenyl ethers in air and fallouts from an e-waste polluted region in southeast China: insight into levels, compositional profiles, and seasonal variation.

    PubMed

    Xu, Feng; Zhang, Gang; Wang, Junxia; Zhang, Wei; Liu, Lili; Lin, Kuangfei

    2015-12-01

    Air and fallout samples were collected seasonally in an e-waste polluted region in southeast of China in 2013-2014. The annual polybrominated diphenyl ethers (PBDEs) concentrations in air and fallout samples were 200 ± 162 pg m(-3) and 320 ± 255 ng g(-1), respectively. The deposition flux calculated from the fallout concentration was 110 ± 77.3 ng m(-2) day(-1). The PBDE levels and deposition fluxes of the samples deployed within the e-waste central area were three to four times higher than those in the surrounding area. The congener profiles in the air samples could be commonly found in commercial penta-BDE mixtures. BDE209 was the most dominant congener in fallout samples. Debromination processes were confirmed to occur both in the air and fallouts due to the minor amounts or inexistence of some congeners in technical PBDE products. The highest gaseous PBDE concentration was found during the summer while lowest during the autumn. PBDE concentration in fallouts turned up higher in the cold months while lower in the warm months. The similarity of deposition fluxes at sites in the e-waste central area indicated a steady PBDE emission source, whereas the significant relationship between deposition fluxes and particle weights at sites in the e-waste surrounding area suggested the scavenging of PBDEs in this area was largely associated with particles.

  11. Climatic impact of the Millennium eruption of Changbaishan volcano in China: New insights from high-precision radiocarbon wiggle-match dating

    NASA Astrophysics Data System (ADS)

    Xu, Jiandong; Pan, Bo; Liu, Tanzhuo; Hajdas, Irka; Zhao, Bo; Yu, Hongmei; Liu, Ruoxin; Zhao, Ping

    2013-01-01

    Changbaishan volcano in northeast China, previously dated to have erupted around the mid-10th century A.D., is renowned for producing one of the largest eruptions in history (magnitude 6.8) and thus speculated to have substantial climatic impact. Here we report a new high-precision 14C wiggle-match age of A.D. 946 ± 3 obtained from a 264 year old tree trunk (with bark) killed during the eruption, using the OxCal's Bayesian modeling approach with 27 sequentially sampled annual rings of decadal intervals. The new chronology conforms well to the calendar date of A.D. 946 for the eruption inferred from historical documentary evidence. We find no stratospherically loaded sulfate spike that might be associated with the A.D. 946 eruption in the global volcanism record from the GISP2 ice core, suggesting the stratospheric sulfate aerosols produced during the eruption were not transported to the arctic region, due probably to its relatively low stratospheric sulfur emission and the seasonal effects of the atmospheric circulation at the time of the eruption that likely occurred in the winter of A.D. 946-947. Since the stratospheric volcanic sulfates are the main cause of large-scale climate perturbations, this finding indicates that the Millennium eruption of Changbaishan volcano might have limited regional climatic effects, rather than global or hemispheric impact as implied by its magnitude.

  12. Association of peripheral differential leukocyte counts with dyslipidemia risk in Chinese patients with hypertension: insight from the China Stroke Primary Prevention Trial[S

    PubMed Central

    Liu, Yanhong; Kong, Xiangyi; Wang, Wen; Fan, Fangfang; Zhang, Yan; Zhao, Min; Wang, Yi; Wang, Yupeng; Wang, Yu; Qin, Xianhui; Tang, Genfu; Wang, Binyan; Xu, Xiping; Hou, Fan Fan; Gao, Wei; Sun, Ningling; Li, Jianping; Venners, Scott A.; Jiang, Shanqun; Huo, Yong

    2017-01-01

    The aim of the present study was to examine the association between peripheral differential leukocyte counts and dyslipidemia in a Chinese hypertensive population. A total of 10,866 patients with hypertension were enrolled for a comprehensive assessment of cardiovascular risk factors using data from the China Stroke Primary Prevention Trial. Plasma lipid levels and total leukocyte, neutrophil, and lymphocyte counts were determined according to standard methods. Peripheral differential leukocyte counts were consistently and positively associated with serum total cholesterol (TC), LDL cholesterol (LDL-C), and TG levels (all P < 0.001 for trend), while inversely associated with HDL cholesterol levels (P < 0.05 for trend). In subsequent analyses where serum lipids were dichotomized (dyslipidemia/normolipidemia), we found that patients in the highest quartile of total leukocyte count (≥7.6 × 109 cells/l) had 1.64 times the risk of high TG [95% confidence interval (CI): 1.46, 1.85], 1.34 times the risk of high TC (95% CI: 1.20, 1.50), and 1.24 times the risk of high LDL-C (95% CI: 1.12, 1.39) compared with their counterparts in the lowest quartile of total leukocyte count. Similar patterns were also observed with neutrophils and lymphocytes. In summary, these findings indicate that elevated differential leukocyte counts are directly associated with serum lipid levels and increased odds of dyslipidemia. PMID:27879312

  13. 2D magnetotelluric imaging of the Anqing-Guichi ore district, Yangtze metallogenic belt, eastern China: An insight into the crustal structure and tectonic units

    NASA Astrophysics Data System (ADS)

    Chen, Xiangbin; Yan, Jiayong

    2016-08-01

    Two parallel NW-trending magnetotelluric (MT) profiles were placed perpendicularly to the main structures of the Anqing-Guichi ore district, one of the seven ore districts in the middle-lower Yangtze River metallogenic belt of eastern China. In October-December 2013, the MT data acquisition was carried out at 117 sites with 0.5-1 km site spacing. The MT data has a good quality in the frequency range between 320 and 0.01 Hz. The dimensionality analysis and 2D resistivity inversion results indicate that: (1) the deep of the ore district with three-dimensional structural characteristics, but two-dimensional structural characteristics for shallow; (2) there is a clear correlation between resistivity and the main geological units of the ore district, as well as correlation with mapped surface faults; (3) the Gandan deep fault (GDF) and Jiangnan deep fault (JNF) extend from the surface to 10 km deep, with dip of NW45°, and dip angles larger than 60°. A series of NE-trending acidic intrusive rocks were controlled by the GDF.

  14. New insight into the correlations between land use and water quality in a coastal watershed of China: Does point source pollution weaken it?

    PubMed

    Zhou, Pei; Huang, Jinliang; Pontius, Robert Gilmore; Hong, Huasheng

    2016-02-01

    Uncovering the associations between land use and river water quality is useful for managing land-based pollution in the catchment-coast continuum. However, it is not clear how land use affects water quality in the context of simultaneous point source (PS) pollution. In this study, we develop a self-organizing map (SOM)-based approach to explore the relationship between land use and water quality in the Minjiang River Watershed, Southeast China. Water samples from 139 headwater sub-watersheds were associated with six land use categories, namely, Woodland, Agriculture, Orchard, Built-up, Unused land and Water. Sampling sites are delineated into six clusters based on six water quality parameters: ammonium-N, nitrate-N, total nitrogen, soluble reactive phosphate, total phosphate and potassium permanganate index. Local relationships between land use and water quality among four clusters that have sufficient sample sizes are further identified. There is no significant land use-water quality correlation in one of the four clusters (including 37 sub-watersheds). And the greater the PS pollution is, the less significant the land use-water quality correlations are in clusters. The results demonstrate how PS pollution weakens the land use-water quality correlation. Our method can help to determine whether non-point source or PS pollution exerts greater influence on the quality of the water coming from watershed. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Effect of Fe(II)/Ce(III) dosage ratio on the structure and anion adsorptive removal of hydrothermally precipitated composites: Insights from EXAFS/XANES, XRD and FTIR.

    PubMed

    Chubar, Natalia; Gerda, Vasyl; Banerjee, Dipanjan; Yablokova, Ganna

    2017-02-01

    In this work, we present material chemistry in the hydrothermal synthesis of new complex structure materials based on various dosage ratios of Fe and Ce (1:0, 2:1, 1:1, 1:2, 0:1), characterize them by the relevant methods that allow characterization of both crystalline and amorphous phases and correlate their structure/surface properties with the adsorptive performance of the five toxic anions. The applied synthesis conditions resulted in the formation of different compounds of Fe and Ce components. The Fe-component was dominated by various phases of Fe hydrous oxides, whereas the Ce-component was composed of various phases of Ce carbonates. The presence of two metal salts in raw materials resulted in the formation of a mesoporous structure and averaged the surface area compared to one metal-based material. The surface of all Fe-Ce composites was abundant in Fe component phases. Two-metal systems showed stronger anion removal performance than one-metal materials. The best adsorption was demonstrated by Fe-Ce based materials that had low crystallinity, that were rich in phases and that exhibited surfaces were abundant in greater number of surface functional groups. Notably, Fe extended fine structures simulated by EXAFS in these better adsorbents were rich from oscillations from both heavy and light atoms. This work provides new insights on the structure of composite inorganic materials useful to develop their applications in adsorption and catalysis. It also presents new inorganic anion exchangers with very high removal potential to fluoride and arsenate.

  16. Molecular epidemiology of genogroup II norovirus infection among hospitalized children with acute gastroenteritis in Suzhou (Jiangsu, China) from 2010 to 2013.

    PubMed

    Fu, Jian-Guang; Ai, Jing; Zhang, Jun; Wu, Qing-Bin; Qi, Xian; Ji, Hong; Jin, Miao; Liu, Cheng; Wang, Shen-Jiao; Shan, Jun; Bao, Chang-Jun; Tang, Fen-Yang; Zhu, Ye-Fei

    2016-06-01

    Noroviruses (NoVs) are the most common cause of acute gastroenteritis in both sporadic and outbreak cases. Genotyping and recombination analyses were performed in order to help getting more knowledge of the distribution and genetic diversity of NoVs in Suzhou, located in Jiangsu province of China. All stool samples were collected from hospitalized children younger than 5 years old with acute gastroenteritis. For genotyping, the open reading frame (ORF) 1 and ORF2 were partially amplified and sequenced. 26.9% of stool samples were positive for genogroup II NoVs. The most common genotype was GII.4 and its variants included Den Haag-2006b, New Orleans-2009, and Sydney-2012. The Den Haag-2006b variants predominated during 2010-2012. In 2013, it was replaced by the Sydney-2012 variant. The second most common genotype was GII.12/GII.3. NoVs could be detected throughout the year, with GII.4 and GII.12/GII.3 coexisting during the cold months, and GII.4 was the main genotype during the warm months. The highest prevalence of NoV was detected in young children aged <24 months. Patients infected with GII.4 had a higher chance of getting moderate fever than other NoV-positive patients, while those infected with GII.12/GII.3 tended to have a mild degree of fever. NoV is an important pathogen responsible for viral gastroenteritis among children in Suzhou. Analyses of NoV circulating between 2010 and 2013 revealed a change of predominant variant of NoV GII.4 in each epidemic season and intergenotype recombinant strains represented an important part. © 2015 Wiley Periodicals, Inc.

  17. High-order Cu(II) chloro-complexes in LiCl brines: Insights from density function theory and molecular dynamics

    NASA Astrophysics Data System (ADS)

    Li, Hui-Ji; Yi, Hai-Bo; Xu, Jia-Jia

    2015-09-01

    Cu(II) complexation by chloride is relevant to the transport of copper in near-surface geologic environments, yet the existence of high-order Cu(II) chloro-complexes still remains in dispute. In this study, the structure characteristics and stabilities of [CuClx]2-xaq (x = 3, 4, 5) complexes have been investigated using density functional theory (DFT) methods and molecular dynamics (MD) simulations. [CuCl3]- and [CuCl4]2- species can both be tracked, while the [CuCl5]3-aq complex cannot be recorded during MD simulations of trace Cu2+ in chloride-rich brines. DFT calculations indicate that contact ion pair (CIP) conformers of [CuCl3]- species are less stable than its solvent separated ion pair (SSIP) conformers, in which one Cl- stays in the second coordination sphere of the centered Cu2+. MD simulations also reveal that the SSIP conformer is apt to appear in the aqueous solution than its CIP conformer. It seems that the third Cl- is more likely in the second coordination shell of center Cu2+ in [CuCl3]-. Meanwhile, the characteristic peak around 385 nm resolved in UV-Vis spectra experiments, which was attributed to the [CuCl3]- complex, could also be resulted from some SSIP structures of the [CuCl3]- complex. In MD simulations, the complex [CuCl4]2-aq is found more stable than [CuCl3]-aq. The surrounding water molecules around [CuClx]2-xaq (x = 3, 4) enhance their stabilities in Cl- brines, especially for [CuCl4]2-aq. The hydration shell of [CuCl4]2-aq species is more intact than that of [CuCl3]2-aq, and the residence time of a water molecule in the second coordination sphere of Cu ion in the [CuCl4]2-aq complex is also obviously longer than that of [CuCl3]-aq. The [CuCl4]2-aq complex can even be recorded in the less concentrated (6.33 m) Cl- solution, while the [CuCl3]-aq complex is tracked only in the 16.32 m Cl- brine. Meanwhile, the possibilities of [CuCl3]-aq and [CuCl4]2-aq complexes found in 16.32 m Cl- solutions both decrease with increasing temperature

  18. Current theories of neuronal information processing performed by Ca2+/calmodulin-dependent protein kinase II with support and insights from computer modelling and simulation.

    PubMed

    Coomber, C

    1998-01-01

    Ca2+/calmodulin-dependent protein kinase II (CaMKII) is concentrated in brain, and is particularly enriched in synaptic structures where it comprises 20-50% of all proteins. The abundant nature of CaMKII and its ability to phosphorylate a wide range of substrate proteins, including itself, earmarks it as a protein kinase that may have a vital role in neuronal information processing and memory. A computer model of CaMKII is investigated that incorporates recent findings about the geometrical arrangement of subunits, the mechanism of Ca(2+)-dependent subunit activation, and Ca(2+)-independent autophosphorylation. The model is framed as a system of nonlinear differential equations. It is demonstrated numerically that (1) CaMKII is tuned to be activated by stimulation protocols associated with the induction of long-term potentiation; (2) the observed slow dissociation of trapped Ca2+/calmodulin may require the autonomy site to be protected from dephosphorylation; and (3) Ca(2+)-independent kinase activity is expressed in a manner akin to a graded switch. The model validates current theories concerning how CaMKII may be a Ca2+ pulse frequency detector, a molecular switch, or a mediator of the threshold for long-term synaptic plasticity.

  19. Insights into dehydrogenative coupling of alcohols and amines catalyzed by a (PNN)-Ru(II) hydride complex: unusual metal-ligand cooperation.

    PubMed

    Zeng, Guixiang; Li, Shuhua

    2011-11-07

    Density functional theory calculations were performed to elucidate the mechanism of dehydrogenative coupling of primary alcohols and amines mediated by a PNN-Ru(II) hydride complex (PNN = (2-(di-tert-butylphosphinomethyl)-6-(diethylaminomethyl)pyridine)). A plausible reaction pathway was proposed which contains three stages: (1) The alcohol dehydrogenation reaction to generate the aldehyde and H(2); (2) The aldehyde-amine condensation reaction to form the hemiaminal intermediate; (3) The dehydrogenation process of the hemiaminal intermediate to yield the final amide product with the liberation of H(2). The first and third stages occur via a similar pathway: (a) Proton transfer from the substrate to the PNN ligand; (b) Intramolecular rearrangement of the deprotonated substrate to form an anagostic complex; (c) Hydride transfer from the deprotonated substrate to the Ru center to yield the trans-dihydride intermediate and the aldehyde (or amide); (d) Benzylic proton migration from the PNN ligand to the metal center forming a dihydrogen complex and subsequent H(2) liberation to regenerate the catalyst. In all these steps, the metal-ligand cooperation plays an essential role. In proton transfer steps (a) and (d), the metal-ligand cooperation is achieved through the aromatization/dearomatization processes of the PNN ligand. While in steps (b) and (c), their collaboration are demonstrated by the formation of an anagostic interaction between Ru and the C-H bond and two ionic hydrogen bonds supported by the PNN ligand.

  20. Insights into photosystem II from isomorphous difference Fourier maps of femtosecond X-ray diffraction data and quantum mechanics/molecular mechanics structural models

    DOE PAGES

    Wang, Jimin; Askerka, Mikhail; Brudvig, Gary W.; ...

    2017-01-12

    Understanding structure–function relations in photosystem II (PSII) is important for the development of biomimetic photocatalytic systems. X-ray crystallography, computational modeling, and spectroscopy have played central roles in elucidating the structure and function of PSII. Recent breakthroughs in femtosecond X-ray crystallography offer the possibility of collecting diffraction data from the X-ray free electron laser (XFEL) before radiation damage of the sample, thereby overcoming the main challenge of conventional X-ray diffraction methods. However, the interpretation of XFEL data from PSII intermediates is challenging because of the issues regarding data-processing, uncertainty on the precise positions of light oxygen atoms next to heavy metalmore » centers, and different kinetics of the S-state transition in microcrystals compared to solution. Lastly, we summarize recent advances and outstanding challenges in PSII structure–function determination with emphasis on the implementation of quantum mechanics/molecular mechanics techniques combined with isomorphous difference Fourier maps, direct methods, and high-resolution spectroscopy.« less

  1. Communication: Librational dynamics in water, sI and sII clathrate hydrates, and ice Ih: Molecular-dynamics insights

    NASA Astrophysics Data System (ADS)

    Burnham, Christian J.; English, Niall J.

    2016-02-01

    Equilibrium molecular-dynamics simulations have been performed for liquid water, and on metastable sI and sII polymorphs of empty hydrate lattices, in addition to ice Ih, in order to study the dynamical properties of librational motion (rotation oscillation) depicted by protons in water molecules. In particular, hydrate lattices were found to display prominent "bifurcated" features, or peaks, at circa 70 and 80-95 meV (or ˜560 and 640-760 cm-1, respectively), also displayed by ice, in essentially quantitative agreement with experimental neutron-scattering data. However, observed differences in dispersion between these librational modes between these two structures (both hydrate polymorphs vis-à-vis ice), owing primarily to density effects, have been decomposed into contributions arising from angular-velocity dynamics about axes in the local molecular frame of water molecules, with in-plane "wagging" and "twisting" rationalising one mode at ˜70 meV, and out-of-plane motion for the higher-frequency band. This was confirmed explicitly by a type of de facto normal-mode analysis, in which only immediate layers of water molecules about the one under consideration were allowed to move. In contrast, liquid water displayed no marked preference for such local in- or out-of-plane modes characterising librational motion, owing to the marked absence of rigid, pentamers or hexamers therein.

  2. Communication: Librational dynamics in water, sI and sII clathrate hydrates, and ice Ih: Molecular-dynamics insights.

    PubMed

    Burnham, Christian J; English, Niall J

    2016-02-07

    Equilibrium molecular-dynamics simulations have been performed for liquid water, and on metastable sI and sII polymorphs of empty hydrate lattices, in addition to ice Ih, in order to study the dynamical properties of librational motion (rotation oscillation) depicted by protons in water molecules. In particular, hydrate lattices were found to display prominent "bifurcated" features, or peaks, at circa 70 and 80-95 meV (or ∼560 and 640-760 cm(-1), respectively), also displayed by ice, in essentially quantitative agreement with experimental neutron-scattering data. However, observed differences in dispersion between these librational modes between these two structures (both hydrate polymorphs vis-à-vis ice), owing primarily to density effects, have been decomposed into contributions arising from angular-velocity dynamics about axes in the local molecular frame of water molecules, with in-plane "wagging" and "twisting" rationalising one mode at ∼70 meV, and out-of-plane motion for the higher-frequency band. This was confirmed explicitly by a type of de facto normal-mode analysis, in which only immediate layers of water molecules about the one under consideration were allowed to move. In contrast, liquid water displayed no marked preference for such local in- or out-of-plane modes characterising librational motion, owing to the marked absence of rigid, pentamers or hexamers therein.

  3. Insights into Photosystem II from Isomorphous Difference Fourier Maps of Femtosecond X-ray Diffraction Data and Quantum Mechanics/Molecular Mechanics Structural Models.

    PubMed

    Wang, Jimin; Askerka, Mikhail; Brudvig, Gary W; Batista, Victor S

    2017-02-10

    Understanding structure-function relations in photosystem II (PSII) is important for the development of biomimetic photocatalytic systems. X-ray crystallography, computational modeling, and spectroscopy have played central roles in elucidating the structure and function of PSII. Recent breakthroughs in femtosecond X-ray crystallography offer the possibility of collecting diffraction data from the X-ray free electron laser (XFEL) before radiation damage of the sample, thereby overcoming the main challenge of conventional X-ray diffraction methods. However, the interpretation of XFEL data from PSII intermediates is challenging because of the issues regarding data-processing, uncertainty on the precise positions of light oxygen atoms next to heavy metal centers, and different kinetics of the S-state transition in microcrystals compared to solution. Here, we summarize recent advances and outstanding challenges in PSII structure-function determination with emphasis on the implementation of quantum mechanics/molecular mechanics techniques combined with isomorphous difference Fourier maps, direct methods, and high-resolution spectroscopy.

  4. Insight into the Development of Dissolution Media for BCS Class II Drugs: A Review from Quality Control and Prediction of In Vivo Performance Perspectives.

    PubMed

    Wu, Chunnuan; Liu, Yan; He, Zhonggui; Sun, Jin

    2016-01-01

    To assess in vivo behavior through in vitro method, the dissolution test is mostly used, both for quality control (QC) and for development purpose. In view of the fact that a dissolution test can hardly achieve two goals at the same time, the design of dissolution testing generally varies along with the development stage of drug products and therefore the selection of dissolution media may change with the goals of the dissolution test. To serve the QC purpose, a dissolution medium is designed to provide a sink condition; for development purpose, the dissolution medium is required to simulate the physiological conditions in the gastrointestinal tract as far as possible. In this review, we intended to provide an initial introduction to the various dissolution media applied for QC and formulation development purposes for poorly water soluble drugs. We focused on these methods like addition of cosolvents, surfactants and utilization of biphasic media, applied to provide sink conditions which are difficult to be achieved by simple aqueous buffers for lipophilic drugs, and introduced the development of physiologically relevant media for human and animals like dog and rat with respect to the choice of buffers, bile salts, lipids and so on. In addition, we further discussed the influence of biorelevant dissolution media on the modification of drug Biopharmaceutical Classification System (BCS) classification, especially for BCS class II drugs with low solubility and high permeability, the solubility of which is relatively sensitive to the presence of bile salts and lipids.

  5. Insights into Photosystem II from Isomorphous Difference Fourier Maps of Femtosecond X-ray Diffraction Data and Quantum Mechanics/Molecular Mechanics Structural Models

    PubMed Central

    2017-01-01

    Understanding structure–function relations in photosystem II (PSII) is important for the development of biomimetic photocatalytic systems. X-ray crystallography, computational modeling, and spectroscopy have played central roles in elucidating the structure and function of PSII. Recent breakthroughs in femtosecond X-ray crystallography offer the possibility of collecting diffraction data from the X-ray free electron laser (XFEL) before radiation damage of the sample, thereby overcoming the main challenge of conventional X-ray diffraction methods. However, the interpretation of XFEL data from PSII intermediates is challenging because of the issues regarding data-processing, uncertainty on the precise positions of light oxygen atoms next to heavy metal centers, and different kinetics of the S-state transition in microcrystals compared to solution. Here, we summarize recent advances and outstanding challenges in PSII structure–function determination with emphasis on the implementation of quantum mechanics/molecular mechanics techniques combined with isomorphous difference Fourier maps, direct methods, and high-resolution spectroscopy. PMID:28217747

  6. Fundamental insights into conformational stability and orbital interactions of antioxidant (+)-catechin species and complexation of (+)-catechin with zinc(II) and oxovanadium(IV)

    NASA Astrophysics Data System (ADS)

    Yasarawan, Nuttawisit; Thipyapong, Khajadpai; Sirichai, Somsak; Ruangpornvisuti, Vithaya

    2013-09-01

    Conformational stability of (+)-catechin species in water has been examined with density functional theory, associated with the polarizable continuum model (PCM) of solvation. Factors such as electron delocalization, lone-pair electron donation and intramolecular hydrogen bonding substantially contribute to the conformational stabilization. Upon deprotonation, the HOMO and LUMO energies for (+)-catechin are both elevated; the energy gaps for the deprotonated species are narrower than the energy gap for the neutral species. The preferential deprotonation occurs at the C3'-, C5-, C7- and C4'-OH groups successively. The pKa value at 9.3 predicted for the most acidic OH group agrees well with previous experimental data; however the values are overestimated for the less acidic OH groups due to limitations of the PCM for charged solutes and/or complex nature of true deprotonation pathways. Formation of hydrogen radicals should be promoted at high pH values following the bond dissociation enthalpies. Complexation of (+)-catechin with either zinc(II) or oxovanadium(IV) is favored at the 1:1 metal-to-ligand (M:L) mole ratio, with the oxovanadium(IV) complex showing higher reaction preference. At M:L = 1:2, formation of two isomeric complexes are plausible for each type of metal ion. Effects of stoichiometry and isomerism on the computational spectral features of the possibly formed metal complexes have been described.

  7. Structural insights into the interaction of the ribosomal P stalk protein P2 with a type II ribosome-inactivating protein ricin

    PubMed Central

    Fan, Xiaojiao; Zhu, Yuwei; Wang, Chongyuan; Niu, Liwen; Teng, Maikun; Li, Xu

    2016-01-01

    Ricin is a type II ribosome-inactivating protein (RIP) that depurinates A4324 at the sarcin-ricin loop of 28 S ribosomal RNA (rRNA), thus inactivating the ribosome by preventing elongation factors from binding to the GTPase activation centre. Recent studies have disclosed that the conserved C-terminal domain (CTD) of eukaryotic ribosomal P stalk proteins is involved in the process that RIPs target ribosome. However, the details of the molecular interaction between ricin and P stalk proteins remain unknown. Here, we report the structure of ricin-A chain (RTA) in a complex with the CTD of the human ribosomal protein P2. The structure shows that the Phe111, Leu113 and Phe114 residues of P2 insert into a hydrophobic pocket formed by the Tyr183, Arg235, Phe240 and Ile251 residues of RTA, while Asp115 of P2 forms hydrogen bonds with Arg235 of RTA. The key residues in RTA and P2 for complex formation were mutated, and their importance was determined by pull-down assays. The results from cell-free translation assays further confirmed that the interaction with P stalk proteins is essential for the inhibition of protein synthesis by RTA. Taken together, our results provide a structural basis that will improve our understanding of the process by which ricin targets the ribosome, which will benefit the development of effective small-molecule inhibitors for use as therapeutic agents. PMID:27886256

  8. The geochemical evolution of the granitoid rocks in the South Qinling Belt: Insights from the Dongjiangkou and Zhashui intrusions, central China

    NASA Astrophysics Data System (ADS)

    Hu, Fangyang; Liu, Shuwen; Ducea, Mihai N.; Zhang, Wanyi; Deng, Zhengbin

    2017-05-01

    Widespread Late Triassic granitoid rocks in the South Qinling Belt (SQB) represent excellent subjects to study the geochemical and geodynamic evolution of magmatic rocks during the collision between the North China Craton and South China Block. In this study, we report new geological, geochemical, zircon U-Pb geochronology and zircon Hf isotopic data for the Dongjiangkou and Zhashui intrusions, two large igneous complexes typical of the SQB. We also summarize published geochemical data of similar granitoid rocks. Our results show that the Dongjiangkou intrusion is composed of ca. 223-214 Ma quartz diorites, tonalites and granodiorites with abundant coeval mafic magmatic enclaves (MME), and the Zhashui intrusion consists of ca. 203-197 Ma monzogranites and K-feldspar granites with rare MME. The Dongjiangkou granitoid rocks are characterized by high K2O, MgO, Rb, and Mg# values, but low TiO2, Sc, and A/CNK (molar Al2O3/(CaO + Na2O + K2O)) values, with εHf(t) values of - 18.1 to - 0.4 and TDM2(Hf) values of 1141-2117 Ma. We suggest that the Dongjiangkou granitoid rocks are formed by magma mixing between 70%-90% melts derived from partial melting of the Neoproterozoic basement rocks of the SQB and 10%-30% mantle-derived mafic melts with minor involvement of Archean to Paleoproterozoic old basement materials of the SQB. The Zhashui granitoid rocks exhibit high K2O, Rb, A/CNK, AMF(Al2O3/(MgO + FeOT)), Al2O3/TiO2 and Rb/Sr values, but low MgO, TiO2, Sc, CaO/Na2O values, with εHf(t) values of - 3.5 to + 2.3 and TDM2(Hf) values of 979-1300 Ma, suggesting they are mainly produced by partial melting of Neoproterozoic metamorphic greywackes mixed with minor amounts of mantle-derived melts. The MME are characterized by low SiO2, Sr/Y ratio, but high MgO, K2O, and Rb contents, with εHf(t) values of - 0.8 to + 4.3 and TDM(Hf) values of 732-905 Ma, suggesting they are produced by partial melting of metasomatized continental lithospheric mantle. A flare-up event is recognized

  9. New insights into PM2.5 chemical composition and sources in two major cities in China during extreme haze events using aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Elser, Miriam; Huang, Ru-Jin; Wolf, Robert; Slowik, Jay G.; Wang, Qiyuan; Canonaco, Francesco; Li, Guohui; Bozzetti, Carlo; Daellenbach, Kaspar R.; Huang, Yu; Zhang, Renjian; Li, Zhengqiang; Cao, Junji; Baltensperger, Urs; El-Haddad, Imad; Prévôt, André S. H.

    2016-03-01

    During winter 2013-2014 aerosol mass spectrometer (AMS) measurements were conducted for the first time with a novel PM2.5 (particulate matter with aerodynamic diameter ≤ 2.5 µm) lens in two major cities of China: Xi'an and Beijing. We denote the periods with visibility below 2 km as extreme haze and refer to the rest as reference periods. During the measurements in Xi'an an extreme haze covered the city for about a week and the total non-refractory (NR)-PM2.5 mass fraction reached peak concentrations of over 1000 µg m-3. During the measurements in Beijing two extreme haze events occurred, but the temporal extent and the total concentrations reached during these events were lower than in Xi'an. Average PM2.5 concentrations of 537 ± 146 and 243 ± 47 µg m-3 (including NR species and equivalent black carbon, eBC) were recorded during the extreme haze events in Xi'an and Beijing, respectively. During the reference periods the measured average concentrations were 140 ± 99 µg m-3 in Xi'an and 75 ± 61 µg m-3 in Beijing. The relative composition of the NR-PM2.5 evolved substantially during the extreme haze periods, with increased contributions of the inorganic components (mostly sulfate and nitrate). Our results suggest that the high relative humidity present during the extreme haze events had a strong effect on the increase of sulfate mass (via aqueous phase oxidation of sulfur dioxide). Another relevant characteristic of the extreme haze is the size of the measured particles. During the extreme haze events, the AMS showed much larger particles, with a volume weighted mode at about 800 to 1000 nm, in contrast to about 400 nm during reference periods. These large particle sizes made the use of the PM2.5 inlet crucial, especially during the severe haze events, where 39 ± 5 % of the mass would have been lost in the conventional PM1 (particulate matter with aerodynamic diameter ≤ 1 µm) inlet. A novel positive matrix factorization procedure was developed to

  10. Syntectonic emplacement of the Triassic biotite-syenogranite intrusions in the Taili area, western Liaoning, NE China: Insights from petrogenesis, rheology and geochronology

    NASA Astrophysics Data System (ADS)

    Li, Weimin; Liu, Yongjiang; Jin, Wei; Neubauer, Franz; Zhao, Yingli; Liang, Chenyue; Wen, Quanbo; Feng, Zhiqiang; Li, Jing; Liu, Qing

    2017-05-01

    The North China Craton (NCC) is one of the oldest cratons in the world, and it recently becomes a hot study area because of large volumes of Mesozoic intrusions associated with lithospheric thinning contributing to cratonic destruction in late Mesozoic times. However, the timing of initial thinning and destruction is still controversial. The Taili area, western Liaoning Province, in the northeastern part of the NCC well exposes the Archean basement rocks and the Mesozoic magmatic rocks with variable plastic deformation. This study focuses on the syntectonic emplacement of the Triassic biotite-syenogranite intrusions, in order to understand their petrogenesis, timing as well as the geological significance. Zircon LA-ICP-MS U-Pb ages reveal that the biotite-syenogranites formed between 246 and 191 Ma, and contain many ancient (2564-2317 Ma) zircon xenocrysts. Geochemical data suggests that the biotite-syenogranites display an adakitic affinity with high Sr/Y = 135-167 and (La/Yb)N = 48-69, as well as negligible Eu anomalies (δEu = 0.87-0.94), high negative zircon εHf(t) values (-15.5 to -21.5) and ancient TDM2 ages (2246-2598 Ma). This data suggests that the parent magmas were generated from partial melting of thickened Archean lower crustal rocks probably due to the bidirectional amalgamation of the NCC with the NE China micro-blocks and the Yangtze Craton in its north and south, respectively. In the middle part of the Taili area, magmatic fabrics are well preserved in the biotite-syenogranite intrusion characterized by the strong preferred orientation of biotite and hornblende crystals, which parallel to the intrusion margin and are slightly oblique to the gneissosity of the sheared host Neoarchean granitic gneisses. The quartz grain size piezometer suggests that the paleo-differential stresses weaken toward to the central part of the intrusion, ranging from 21.40-22.22 MPa to 16.74-19.34 MPa, during quartz crystallization in the emplacement stage. This allow

  11. New insights into the magmatism in the northern margin of the South China Sea: Spatial features and volume of intraplate seamounts

    NASA Astrophysics Data System (ADS)

    Fan, Chaoyan; Xia, Shaohong; Zhao, Fang; Sun, Jinlong; Cao, Jinghe; Xu, Huilong; Wan, Kuiyuan

    2017-06-01

    The extensive intraplate seamounts are obvious features in the northern South China Sea (SCS). However, the distribution, volume, and origin of these seamounts are not well understood, which greatly hinders our understanding of magmatism in the SCS. Based on high-resolution bathymetric data and 147 seismic profiles, and combining gravity and magnetic data, we first identify 45 seamounts in the northern margin of the SCS and simulate their shape with elliptical cones. Results show that the total volume of these 45 seamounts above seafloor is estimated at about 1885-3078 km3 and the total volume of intrusive magma above Moho is about 0.15 Mkm3, which is close to the estimates for classic large igneous provinces across the world. These seamounts are mostly located on the continental slope with thin crust (approximately 12-18 km), which reduces the overlying pressure and shortens the magmatic conduits. The dominant azimuth of elliptical major axis in seamounts is consistent with the synrift and synspreading fault strikes (NE-NEE), indicating that these preexisting faults provide magmatic conduits for the subsequent postrift intraplate seamounts. Based on three existing clues, i.e., (1) the intraplate seamounts, high velocity layer and Hainan mantle plume are contiguous in 3-D space, (2) the high-velocity layer is thicker beneath the continental shelf but thinner beneath the slope, and (3) the basalts dredged from certain seamounts show OIB-type geochemical features, we propose a magmatic upwelling pattern which contains Hainan mantle plume to explain the spatial and morphological characteristics of these intraplate seamounts.

  12. National Assessment of Statin Therapy in Patients Hospitalized with Acute Myocardial Infarction: Insight from China PEACE-Retrospective AMI Study, 2001, 2006, 2011

    PubMed Central

    Zhang, Lihua; Li, Jing; Li, Xi; Nasir, Khurram; Zhang, Haibo; Wu, Yongjian; Hu, Shuang; Wang, Qing; Downing, Nicholas S.; Desai, Nihar R.; Masoudi, Frederick A.; Spertus, John A.; Krumholz, Harlan M.; Jiang, Lixin

    2016-01-01

    Background Statin therapy is among the most effective treatments to improve short- and long-term mortality after acute myocardial infarction. The use of statin, and the intensity of their use, has not been described in acute myocardial infarction patients in China, a country with a rapidly growing burden of cardiovascular disease. Methods and Results Using a nationally representative sample of patients with acute myocardial infarction admitted to 162 Chinese hospitals in 2001, 2006 and 2011, we identified 14,958 patients eligible for statin therapy to determine rates of statin use and the intensity of statin therapy, defined as those statin regimens with expected low-density lipoprotein cholesterol lowering of at least 40%, to identify factors associated with the use of statin therapy. Statin use among hospitalized patients with acute myocardial infarction increased from 27.9% in 2001 to 72.5% in 2006, and 88.8% in 2011 (P<0.001 for trend). Regional variation in statin use correspondingly decreased over time. Among treated patients, those receiving intensive statin therapy increased from 1.0% in 2001 to 24.2% in 2006 to 57.2% in 2011(P<0.001 for trend). Patients without low-density lipoprotein cholesterol measured were less likely to be treated with statin or to receive intensive therapy. Conclusions The use of statin therapy has dramatically increased over the past decade in Chinese patients with acute myocardial infarction. However, half of patients still did not receive intensive statin therapy in 2011.Given that guidelines strongly endorse intensive statin therapy for acute myocardial infarction patients, initiatives promoting the use of statin therapy, with attention to treatment intensity, would support further improvements in practice. PMID:27058862

  13. Insights from heavy minerals and zircon U-Pb ages into the middle Miocene-Pliocene provenance evolution of the Yinggehai Basin, northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Jiang, Tao; Cao, Licheng; Xie, Xinong; Wang, Zhenfeng; Li, Xushen; Zhang, Yingzhao; Zhang, Daojun; Sun, Hui

    2015-08-01

    The well-preserved Cenozoic sedimentary record in the Yinggehai Basin, South China Sea, is suitable to explore the tectonic and climatic evolution of SE Asia. Red River, a large-scale fluvial system in this region, was previously regarded as the major sediment source for the basin. Here we combine heavy mineral analysis and detrital zircon U-Pb dating to shed new light on the middle Miocene-Pliocene provenance evolution at a basin scale. The results clearly reveal potential source areas additional to the Red River. Sediments have been delivered to the proximal areas from Hainan Island, as indicated by the high zircon content and the Yanshanian U-Pb ages in the southern segment of the Yingdong Slope. A provenance from Central Vietnam is explicitly discerned in the upper Miocene of the Central Depression, where sediments are characterized by few metamorphic heavy minerals and the U-Pb age pattern peaking at around 250 Ma and 440 Ma. Coeval large-scale relative sea-level fall and rapid exhumation along the Vietnamese margin together may have facilitated this long-distance sediment transport. Provenance of sediments from the Red River seems to change over time. Song Lo River, on the north side of the main stream, probably flowed from the NE and carried Neoproterozoic-early Paleozoic zircons to the Yinggehai Basin during the middle Miocene. Since the late Miocene, rocks along the Red River Fault Zone have become the dominant source. Subsequently, widespread metamorphic minerals in the Central Depression of the Yinggehai Basin, combined with the strong river incision and high offshore sedimentation rates, indicate an increased sediment supply from the Red River in the Pliocene.

  14. Primary uranium sources for sedimentary-hosted uranium deposits in NE China: insight from basement igneous rocks of the Erlian Basin

    NASA Astrophysics Data System (ADS)

    Bonnetti, Christophe; Cuney, Michel; Bourlange, Sylvain; Deloule, Etienne; Poujol, Marc; Liu, Xiaodong; Peng, Yunbiao; Yang, Jianxing

    2017-03-01

    Carboniferous-Permian, Triassic and Jurassic igneous basement rocks around the Erlian Basin in northeast China have been investigated through detailed mineralogical, whole-rock geochemistry, geochronological data and Sm-Nd isotope studies. Carboniferous-Permian biotite granites and volcanic rocks belong to a calc-alkaline association and were emplaced during the Late Carboniferous-Early Permian (313 ± 1-286 ± 2 Ma). These rocks are characterised by positive ɛNd( t) (3.3-5.3) and fairly young T DM model ages (485-726 Ma), suggesting a dominant derivation from partial melting of earlier emplaced juvenile source rocks. Triassic biotite granites belong to a high-K calc-alkaline association and were emplaced during the Middle Triassic (243 ± 3-233 ± 2 Ma). Their negative ɛNd( t) (-2 to -0.1) and higher T DM model ages (703-893 Ma) suggest a contribution from Precambrian crust during the magma generation processes, leading to a strong enrichment in K and incompatible elements such as Th and U. Highly fractionated magmas crystallised in U-rich biotite (up to 21 ppm U) and two-mica granites. In biotite granite, the major U-bearing minerals are uranothorite and allanite. They are strongly metamict and the major part of their uranium (90 %) has been released from the mineral structure and was available for leaching. Mass balance calculations show that the Triassic biotite granites may have, at least, liberated ˜14,000 t U/km3 and thus correspond to a major primary uranium source for the U deposits hosted in the Erlian Basin.

  15. Insights into the subsurface transport of As(V) and Se(VI) in produced water from hydraulic fracturing using soil samples from Qingshankou Formation, Songliao Basin, China.

    PubMed

    Chen, Season S; Sun, Yuqing; Tsang, Daniel C W; Graham, Nigel J D; Ok, Yong Sik; Feng, Yujie; Li, Xiang-Dong

    2017-04-01

    Produced water is a type of wastewater generated from hydraulic fracturing, which may pose a risk to the environment and humans due to its high ionic strength and the presence of elevated concentrations of metals/metalloids that exceed maximum contamination levels. The mobilization of As(V) and Se(VI) in produced water and selected soils from Qingshankou Formation in the Songliao Basin in China were investigated using column experiments and synthetic produced water whose quality was representative of waters arising at different times after well creation. Temporal effects of produced water on metal/metalloid transport and sorption/desorption were investigated by using HYDRUS-1D transport modelling. Rapid breakthrough and long tailings of As(V) and Se(VI) transport were observed in Day 1 and Day 14 solutions, but were reduced in Day 90 solution probably due to the elevated ionic strength. The influence of produced water on the hydrogeological conditions (i.e., change between equilibrium and non-equilibrium transport) was evidenced by the change of tracer breakthrough curves before and after the leaching of produced water. This possibly resulted from the sorption of polyacrylamide (PAM (-CH2CHCONH2-)n) onto soil surfaces, through its use as a friction reducer in fracturing solutions. The sorption was found to be reversible in this study. Minimal amounts of sorbed As(V) were desorbed whereas the majority of sorbed Se(VI) was readily leached out, to an extent which varied with the composition of the produced water. These results showed that the mobilization of As(V) and Se(VI) in soil largely depended on the solution pH and ionic strength. Understanding the differences in metal/metalloid transport in produced water is important for proper risk management. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Elemental and Sr-Nd-Pb isotope geochemistry of the Cenozoic basalts in Southeast China: Insights into their mantle sources and melting processes

    NASA Astrophysics Data System (ADS)

    Sun, Pu; Niu, Yaoling; Guo, Pengyuan; Ye, Lei; Liu, Jinju; Feng, Yuexing

    2017-02-01

    We analyzed whole-rock major and trace elements and Sr-Nd-Pb isotopes of the Cenozoic basalts in Southeast China to investigate their mantle source characteristics and melting process. These basalts are spatially associated with three extensional fault systems parallel to the coast line. After correction for the effect of olivine microlites on bulk-rock compositions and the effect of crystal fractionation, we obtained primitive melt compositions for these samples. These primitive melts show increasing SiO2, Al2O3 but decreasing FeO, MgO, TiO2, P2O5, CaO and CaO/Al2O3 from the interior to the coast. Such spatial variations of major element abundances and ratios are consistent with a combined effect of fertile source compositional variation and increasing extent and decreasing pressure of decompression melting from beneath the thick lithosphere in the interior to beneath the thin lithosphere in the coast. These basalts are characterized by incompatible element enrichment but varying extent of isotopic depletion. This element-isotope decoupling is most consistent with recent mantle source enrichment by means of low-degree melt metasomatism that elevated incompatible element abundances without yet having adequate time for isotopic ingrowth in the mantle source regions. Furthermore, Sr and Nd isotope ratios show significant correlations with Nb/Th, Nb/La, Sr/Sr* and Eu/Eu*, which substantiates the presence of recycled upper continental crustal material in the mantle sources of these basalts. Pb isotope ratios also exhibit spatial variation, increasing from the interior to the coastal area. The significant correlations of major element abundances with Pb isotope ratios indicate that the Pb isotope variations also result from varied extent and pressure of decompression melting. We conclude that the elevated Pb isotope ratios from the interior to coast are consistent with increasing extent of decompression melting of the incompatible element depleted mantle matrix, which

  17. Insights into the evolution of pathogenicity of Escherichia coli from genomic analysis of intestinal E. coli of Marmota himalayana in Qinghai–Tibet plateau of China

    PubMed Central

    Lu, Shan; Jin, Dong; Wu, Shusheng; Yang, Jing; Lan, Ruiting; Bai, Xiangning; Liu, Sha; Meng, Qiong; Yuan, Xuejiao; Zhou, Juan; Pu, Ji; Chen, Qiang; Dai, Hang; Hu, Yuanyuan; Xiong, Yanwen; Ye, Changyun; Xu, Jianguo

    2016-01-01

    Escherichia coli is both of a widespread harmless gut commensal and a versatile pathogen of humans. Domestic animals are a well-known reservoir for pathogenic E. coli. However, studies of E. coli populations from wild animals that have been separated from human activities had been very limited. Here we obtained 580 isolates from intestinal contents of 116 wild Marmot Marmota himalayana from Qinghai–Tibet plateau, China, with five isolates per animal. We selected 125 (hereinafter referred to as strains) from the 580 isolates for genome sequencing, based on unique pulse field gel electrophoresis patterns and at least one isolate per animal. Whole genome sequence analysis revealed that all 125 strains carried at least one and the majority (79.2%) carried multiple virulence genes based on the analysis of 22 selected virulence genes. In particular, the majority of the strains carried virulence genes from different pathovars as potential 'hybrid pathogens'. The alleles of eight virulence genes from the Marmot E. coli were found to have diverged earlier than all known alleles from human and other animal E. coli. Phylogenetic analysis of the 125 Marmot E. coli genomes and 355 genomes selected from 1622 human and other E. coli strains identified two new phylogroups, G and H, both of which diverged earlier than the other phylogroups. Eight of the 12 well-known pathogenic E. coli lineages were found to share a most recent common ancestor with one or more Marmot E. coli strains. Our results suggested that the intestinal E. coli of the Marmots contained a diverse virulence gene pool and is potentially pathogenic to humans. These findings provided a new understanding of the evolutionary origin of pathogenic E. coli. PMID:27924811

  18. Mineralogy and geochemistry of claystones from the Guadalupian-Lopingian boundary at Penglaitan, South China: Insights into the pre-Lopingian geological events

    NASA Astrophysics Data System (ADS)

    Zhong, Yu-Ting; He, Bin; Xu, Yi-Gang

    2013-01-01

    The Guadalupian-Lopingian (G/L) boundary, at a stratigraphically well-documented outcrop in Penglaitan, Guangxi Autonomous Region, South China, has been approved as the Global Stratotype Section and Point (GSSP). Several volcanic ashes or tuffs occur at this boundary, but their mineralogy and geochemistry are not available yet and no reliable age for this boundary has been obtained. A combined study of mineralogy, geochemistry and geochronology has been carried out in this study on six layers of claystones collected below (Group 1) and above (Group 2) the G/L boundary at the Penglaitan section. Both Group 1 and Group 2 claystones are likely clastic in origin, rather than volcanic ashes as previously thought. Thus the Penglaitan claystones are not suitable for age determination of the G/L boundary. They are significantly different in terms of mineralogy and geochemistry. Specifically, Group 1 claystones are likely derived from a mafic source which is genetically related to the Emeishan large igneous province, therefore providing additional evidence for the synchroneity between the G/L boundary mass extinction and the Emeishan volcanism. Group 2 samples were derived from a felsic source, of which zircons yield an age spectrum peaked at 262 ± 3 Ma, undistinguishable within the uncertainty from the currently accepted G/L boundary age (260.4 ± 0.4 Ma). Nevertheless, Group 2 samples are not related to Emeishan volcanism, because their negative zircon ɛHf(t) values differ significantly from those of Emeishan magmas and trace element compositions of zircons are indicative of an arc source, rather than a within-plate source. In consideration of paleogeographic reconstruction, we propose that the Group 2 claystones may have been derived from continental arcs during the palaeo-Tethys evolution. This is the first sedimentary evidence for Permian continental arc in the northern margin of palaeo-Tethys.

  19. Insights into the evolution of pathogenicity of Escherichia coli from genomic analysis of intestinal E. coli of Marmota himalayana in Qinghai-Tibet plateau of China.

    PubMed

    Lu, Shan; Jin, Dong; Wu, Shusheng; Yang, Jing; Lan, Ruiting; Bai, Xiangning; Liu, Sha; Meng, Qiong; Yuan, Xuejiao; Zhou, Juan; Pu, Ji; Chen, Qiang; Dai, Hang; Hu, Yuanyuan; Xiong, Yanwen; Ye, Changyun; Xu, Jianguo

    2016-12-07

    Escherichia coli is both of a widespread harmless gut commensal and a versatile pathogen of humans. Domestic animals are a well-known reservoir for pathogenic E. coli. However, studies of E. coli populations from wild animals that have been separated from human activities had been very limited. Here we obtained 580 isolates from intestinal contents of 116 wild Marmot Marmota himalayana from Qinghai-Tibet plateau, China, with five isolates per animal. We selected 125 (hereinafter referred to as strains) from the 580 isolates for genome sequencing, based on unique pulse field gel electrophoresis patterns and at least one isolate per animal. Whole genome sequence analysis revealed that all 125 strains carried at least one and the majority (79.2%) carried multiple virulence genes based on the analysis of 22 selected virulence genes. In particular, the majority of the strains carried virulence genes from different pathovars as potential 'hybrid pathogens'. The alleles of eight virulence genes from the Marmot E. coli were found to have diverged earlier than all known alleles from human and other animal E. coli. Phylogenetic analysis of the 125 Marmot E. coli genomes and 355 genomes selected from 1622 human and other E. coli strains identified two new phylogroups, G and H, both of which diverged earlier than the other phylogroups. Eight of the 12 well-known pathogenic E. coli lineages were found to share a most recent common ancestor with one or more Marmot E. coli strains. Our results suggested that the intestinal E. coli of the Marmots contained a diverse virulence gene pool and is potentially pathogenic to humans. These findings provided a new understanding of the evolutionary origin of pathogenic E. coli.

  20. Coupled pyrite concentration and sulfur isotopic insight into the paleo sulfate-methane transition zone (SMTZ) in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Lin, Qi; Wang, Jiasheng; Taladay, Katie; Lu, Hongfeng; Hu, Gaowei; Sun, Fei; Lin, Rongxiao

    2016-01-01

    The sulfate-methane transition zone (SMTZ) is an important diagenetic redox boundary within marine sediments where the anaerobic oxidation of methane (AOM), coupled with bacterial sulfate reduction, can promote sulfur isotopic enrichments in several solid phase minerals including pyrite (FeS2). Authigenic pyrite can form in concentrated abundances within the SMTZ and as such, can be used as a proxy to identify paleo-SMTZs. This study uses enrichments in 34S and anomalously high abundances of authigenic pyrites in 287 samples from the northern South China Sea (SCS) to determine the paleo-SMTZ. The pyrite samples were collected from sediment cores acquired at three sites, each of which are known to be located in natural gas hydrate-bearing regions. We assess the relative abundances of authigenic pyrites, the types of pyrite morphologies recovered in the cored sediments, and the sulfur isotopic values of recovered pyrite samples using two methods: (1) handpicked sample analysis using a binocular microscope, and (2) the chromium reduction method. Our results show that pyrite concentrations and sulfur isotopic compositions exhibit synchronous fluctuations, particularly from 6.8 m below seafloor (mbsf) to 8.4 mbsf at all three study sites. There is a significant increase in the occurrence of rod-like pyrite morphology within this key interval. We define the position of the paleo-SMTZ by the presence of anomalously high accumulations of pyrites at greater than 5.0 wt.% using the handpicking method or greater than 0.5 wt.% via the chromium reduction method, along with positive Δδ34S excursions greater than 10.0‰ VCDT. We discovered a regional paleo-SMTZ that is shallower than the modern SMTZ, suggesting a previous period of elevated methane flux from depth, possibly related to widespread gas hydrate dissociation.

  1. Intersection patterns of normal faults in the Lufeng Sag of Pearl River Mouth Basin, China: Insights from 4D physical simulations

    NASA Astrophysics Data System (ADS)

    Yu, Fusheng; Koyi, Hemin; Zhang, Xiangtao

    2016-12-01

    Interpretation of seismic data from the Lufeng Sag of the Pearl River Mouth Basin (PRMB) in the northern part of South China Sea shows that different intersection patterns developed in the cover units above basement normal faults. A series of analogue models are used to investigate the intersection patterns and deformation in the sedimentary cover sequences above a basement horst bounded by two non-parallel faults. Modelling results show that during their upward propagation, the basement faults may intersect within the cover sequences and form a graben above the basement horst. Length and width of the graben increase with cover thickness. The strike and dip intersection points are controlled directly by the thickness of the cover sequences, dip and strike of the basement faults, and width of the basement horst. The intersection point migrates along the axis of the graben toward the wide end of the basement horst, when the cover sequence thickens. In contrast, it migrates toward the narrow end of the basement horst, where both fault dip and angle of strike difference increase. The intersection point moves upward with increasing width of the basement horst crest. Model profiles also indicate that in the presence of a ductile layer between the cover and basement such intersection patterns do not form. Interpretation of seismic data and model results show that the intersection pattern developed in the Lufeng Sag is a result of propagation of basement faults into cover units during different extension stages of the basin. Results of this study can be applied to many other sedimentary basins where such fault intersection patterns are likely to form when non-parallel conjugate basement faults are active during sedimentation.

  2. Crystal Structures of Type-II Inositol Polyphosphate 5-Phosphatase INPP5B with Synthetic Inositol Polyphosphate Surrogates Reveal New Mechanistic Insights for the Inositol 5-Phosphatase Family

    PubMed Central

    2016-01-01

    The inositol polyphosphate 5-phosphatase INPP5B hydrolyzes the 5-phosphate group from water- and lipid-soluble signaling messengers. Two synthetic benzene and biphenyl polyphosphates (BzP/BiPhPs), simplified surrogates of inositol phosphates and phospholipid headgroups, were identified by thermodynamic studies as potent INPP5B ligands. The X-ray structure of the complex between INPP5B and biphenyl 3,3′,4,4′,5,5′-hexakisphosphate [BiPh(3,3′,4,4′,5,5′)P6, IC50 5.5 μM] was determined at 2.89 Å resolution. One inhibitor pole locates in the phospholipid headgroup binding site and the second solvent-exposed ring binds to the His-Tag of another INPP5B molecule, while a molecule of inorganic phosphate is also present in the active site. Benzene 1,2,3-trisphosphate [Bz(1,2,3)P3] [one ring of BiPh(3,3′,4,4′,5,5′)P6] inhibits INPP5B ca. 6-fold less potently. Co-crystallization with benzene 1,2,4,5-tetrakisphosphate [Bz(1,2,4,5)P4, IC50 = 6.3 μM] yielded a structure refined at 2.9 Å resolution. Conserved residues among the 5-phosphatase family mediate interactions with Bz(1,2,4,5)P4 and BiPh(3,3′,4,4′,5,5′)P6 similar to those with the polar groups present in positions 1, 4, 5, and 6 on the inositol ring of the substrate. 5-Phosphatase specificity most likely resides in the variable zone located close to the 2- and 3-positions of the inositol ring, offering insights to inhibitor design. We propose that the inorganic phosphate present in the INPP5B–BiPh(3,3′,4,4′,5,5′)P6 complex mimics the postcleavage substrate 5-phosphate released by INPP5B in the catalytic site, allowing elucidation of two new key features in the catalytic mechanism proposed for the family of phosphoinositide 5-phosphatases: first, the involvement of the conserved Arg-451 in the interaction with the 5-phosphate and second, identification of the water molecule that initiates 5-phosphate hydrolysis. Our model also has implications for the proposed “moving metal” mechanism

  3. Crystal Structures of Type-II Inositol Polyphosphate 5-Phosphatase INPP5B with Synthetic Inositol Polyphosphate Surrogates Reveal New Mechanistic Insights for the Inositol 5-Phosphatase Family.

    PubMed

    Mills, Stephen J; Silvander, Camilla; Cozier, Gyles; Trésaugues, Lionel; Nordlund, Pär; Potter, Barry V L

    2016-03-08

    The inositol polyphosphate 5-phosphatase INPP5B hydrolyzes the 5-phosphate group from water- and lipid-soluble signaling messengers. Two synthetic benzene and biphenyl polyphosphates (BzP/BiPhPs), simplified surrogates of inositol phosphates and phospholipid headgroups, were identified by thermodynamic studies as potent INPP5B ligands. The X-ray structure of the complex between INPP5B and biphenyl 3,3',4,4',5,5'-hexakisphosphate [BiPh(3,3',4,4',5,5')P6, IC50 5.5 μM] was determined at 2.89 Å resolution. One inhibitor pole locates in the phospholipid headgroup binding site and the second solvent-exposed ring binds to the His-Tag of another INPP5B molecule, while a molecule of inorganic phosphate is also present in the active site. Benzene 1,2,3-trisphosphate [Bz(1,2,3)P3] [one ring of BiPh(3,3',4,4',5,5')P6] inhibits INPP5B ca. 6-fold less potently. Co-crystallization with benzene 1,2,4,5-tetrakisphosphate [Bz(1,2,4,5)P4, IC50 = 6.3 μM] yielded a structure refined at 2.9 Å resolution. Conserved residues among the 5-phosphatase family mediate interactions with Bz(1,2,4,5)P4 and BiPh(3,3',4,4',5,5')P6 similar to those with the polar groups present in positions 1, 4, 5, and 6 on the inositol ring of the substrate. 5-Phosphatase specificity most likely resides in the variable zone located close to the 2- and 3-positions of the inositol ring, offering insights to inhibitor design. We propose that the inorganic phosphate present in the INPP5B-BiPh(3,3',4,4',5,5')P6 complex mimics the postcleavage substrate 5-phosphate released by INPP5B in the catalytic site, allowing elucidation of two new key features in the catalytic mechanism proposed for the family of phosphoinositide 5-phosphatases: first, the involvement of the conserved Arg-451 in the interaction with the 5-phosphate and second, identification of the water molecule that initiates 5-phosphate hydrolysis. Our model also has implications for the proposed "moving metal" mechanism.

  4. Computational insights on the geometrical arrangements of Cu(II) with a mixed-donor N3S3 macrobicyclic ligand.

    PubMed

    Algarra, Andrés G; Aullón, Gabriel; Bernhardt, Paul V; Martínez, Manuel

    2014-01-06

    The macrobicyclic mixed-donor N3S3 cage ligand AMME-N3S3sar (1-methyl-8-amino-3,13,16-trithia-6,10,19-triazabicyclo[6.6.6]eicosane) can form complexes with Cu(II) in which it acts as hexadentate (N3S3) or tetradentate (N2S2) donor. These two complexes are in equilibrium that is strongly influenced by the presence of halide ions (Br(-) and Cl(-)) and the nature of the solvent (DMSO, MeCN, and H2O). In the absence of halides the hexadentate coordination mode of the ligand is preferred and the encapsulated complex ("Cu-in(2+)") is formed. Addition of halide ions in organic solvents (DMSO or MeCN) leads to the tetradentate complex ("Cu-out(+)") in a polyphasic kinetic process, but no Cu-out(+) complex is formed when the reaction is performed in water. Here we applied density functional theory calculations to study the mechanism of this interconversion as well as to understand the changes in the reactivity associated with the presence of water. Calculations were performed at the B3LYP/(SDD,6-31G**) level, in combination with continuum (MeCN) or discrete-continuum (H2O) solvent models. Our results show that formation of Cu-out(+) in organic media is exergonic and involves sequential halide-catalyzed inversion of the configuration of a N-donor of the macrocycle, rapid halide coordination, and inversion of the configuration of a S-donor. In aqueous solution the solvent is found to have an effect on both the thermodynamics and the kinetics of the reaction. Thermodynamically, the process becomes endergonic mainly due to the preferential solvation of halide ions by water, while the kinetics is influenced by formation of a network of H-bonded water molecules that surrounds the complex.

  5. Synthesis and structure of 1,3-dimethyl-5-(p-sulfonamide-phenylazo)-6-aminouracil and its Ni(II) complex: Topological insights and investigation for noncovalent interactions

    NASA Astrophysics Data System (ADS)

    Debnath, Diptanu; Roy, Subhadip; Purkayastha, Atanu; Bauzá, Antonio; Choudhury, Rupasree; Ganguly, Rakesh; Frontera, Antonio; Misra, Tarun Kumar

    2017-08-01

    The azo-derivative, 1,3-dimethyl-5-(p-sulfonamide-phenylazo)-6-aminouracil (HL) containing 6-aminouracil (a biomolecule) and sulfonamide functionality (commonly found in sulfa-drugs), and its Ni(II) complex, NiIIL2 were synthesized. Single-crystal X-ray diffraction studies show that the ligand (HL) consists of an E conformation about the azo-linkage with a nearly planar geometry and the complex possesses distorted square planar geometry. The H-bonded underlying networks of HL and NiIIL2 were topologically classified revealing distinct topological types, namely tts and hxl, respectively. Moreover, topology of molecular packings in HL and NiIIL2 has also been discussed. Density functional theory (DFT) calculations, at the M06-2X/def2TZVP level of theory, are employed to characterize a great variety of non-covalent interactions that explicitly show the importance of antiparallel stacking interactions established by π--π+ interactions and H-bonds in the self-assembled dimmers in HL and lp-π/C-H⋯π interactions in NiIIL2. The results of NMR and UV-vis spectroscopies evidence that the ligand exists in hydrazone-imine-keto (B) tautomeric form in solution. The ligand absorption bands consist of the overlapping bands of π→π* and n→π* transitions. The complex experiences electronic transitions that consist of basically ILCT in character with some sort of participation of the atomic d-orbitals of the nickel. The pKa value of the ligand is found to be 4.09.

  6. Whirlin interacts with espin and modulates its actin-regulatory function: an insight into the mechanism of Usher syndrome type II.

    PubMed

    Wang, Le; Zou, Junhuang; Shen, Zuolian; Song, E; Yang, Jun

    2012-02-01

    Whirlin mutations cause retinal degeneration and hearing loss in Usher syndrome type II (USH2) and non-syndromic deafness, DFNB31. Its protein recruits other USH2 causative proteins to form a complex at the periciliary membrane complex in photoreceptors and the ankle link of the stereocilia in hair cells. However, the biological function of this USH2 protein complex is largely unknown. Using a yeast two-hybrid screen, we identified espin, an actin-binding/bundling protein involved in human deafness when defective, as a whirlin-interacting protein. The interaction between these two proteins was confirmed by their coimmunoprecipitation and colocalization in cultured cells. This interaction involves multiple domains of both proteins and only occurs when espin does not bind to actin. Espin was partially colocalized with whirlin in the retina and the inner ear. In whirlin knockout mice, espin expression changed significantly in these two tissues. Further studies found that whirlin increased the mobility of espin and actin at the actin bundles cross-linked by espin and, eventually, affected the dimension of these actin bundles. In whirlin knockout mice, the stereocilia were thickened in inner hair cells. We conclude that the interaction between whirlin and espin and the balance between their expressions are required to maintain the actin bundle network in photoreceptors and hair cells. Disruption of this actin bundle network contributes to the pathogenic mechanism of hearing loss and retinal degeneration caused by whirlin and espin mutations. Espin is a component of the USH2 protein complex and could be a candidate gene for Usher syndrome.

  7. Structural insights into the editing of germ-line-encoded interactions between T-cell receptor and MHC class II by Vα CDR3.

    PubMed

    Deng, Lu; Langley, Ries J; Wang, Qian; Topalian, Suzanne L; Mariuzza, Roy A

    2012-09-11

    The conserved diagonal docking mode observed in structures of T-cell receptors (TCRs) bound to peptide-MHC ligands is believed to reflect coevolution of TCR and MHC genes. This coevolution is supported by the conservation of certain interactions between the germ-line-encoded complementarity-determining region (CDR)1 and CDR2 loops of TCR and MHC. However, the rules governing these interactions are not straightforward, even when the same variable (V) region recognizes the same MHC molecule. Here, we demonstrate that the somatically generated CDR3 loops can markedly alter evolutionarily selected contacts between TCR and MHC ("CDR3 editing"). To understand CDR3 editing at the atomic level, we determined the structure of a human melanoma-specific TCR (G4) bound to the MHC class II molecule HLA-DR1 and an epitope from mutant triose phosphate isomerase (mutTPI). A comparison of the G4-mutTPI-DR1 complex with a complex involving a TCR (E8) that uses the same Vα region to recognize the same mutTPI-DR1 ligand as G4 revealed that CDR1α adopts markedly different conformations in the two TCRs, resulting in an almost entirely different set of contacts with MHC. Based on the structures of unbound G4 and E8, the distinct conformations of CDR1α in these TCRs are not induced by binding to mutTPI-DR1 but result from differences in the length and sequence of CDR3α that are transmitted to CDR1α. The editing of germ-line-encoded TCR-MHC interactions by CDR3 demonstrates that these interactions possess sufficient intrinsic flexibility to accommodate large structural variations in CDR3 and, consequently, in the TCR-binding site.

  8. Midostaurin, a Novel Protein Kinase Inhibitor for the Treatment of Acute Myelogenous Leukemia: Insights from Human Absorption, Metabolism and Excretion Studies of a BDDCS II Drug.

    PubMed

    He, Handan; Tran, Phi; Gu, Helen; Tedesco, Vivienne; Zhang, Jin; Lin, Wen; Gatlik, Ewa; Klein, Kai; Heimbach, Tycho

    2017-03-07

    The absorption, metabolism and excretion of midostaurin, a potent class III tyrosine protein kinase inhibitor for acute myelogenous leukemia, were evaluated in healthy subjects. A microemulsion formulation was chosen to optimize absorption. After a 50 mg [14C]midostaurin dose, oral absorption was high (> 90%) and relatively rapid. In plasma, the major circulating components were midostaurin (22%), CGP52421 (32.7%), and CGP62221 (27.7%). Long plasma half-lives were observed for midostaurin (20.3 h), CGP52421 (495 h), and CGP62221 (33.4 h). Through careful mass-balance study design, the recovery achieved was good (81.6%), despite the long radioactivity half-lives. Most of the radioactive dose was recovered in feces (77.6%) mainly as metabolites; as only 3.43% was unchanged, suggesting mainly hepatic metabolism. Renal elimination was minor (4%). Midostaurin metabolism pathways involved hydroxylation, O demethylation, amide hydrolysis and N demethylation. High plasma CGP52421 and CGP62221 exposures in humans, along with relatively potent cell-based IC50 for FLT3-ITD inhibition, suggested that the antileukemic activity in AML patients may also be maintained by the metabolites. Very high plasma protein binding (>99%) required equilibrium gel filtration to identify differences between humans and animals. As midostaurin, CGP52421 and CGP62221 are metabolized mainly by CYP3A4 and are inhibitors/inducers for CYP3A, potential drug-drug interactions with mainly CYP3A4 modulators/CYP3A substrates could be expected. Given its low aqueous solubility, high oral absorption and extensive metabolism (> 90%), midostaurin is a BCS/BDDCS class II drug in human, consistent with rat BDDCS in vivo data showing high absorption (>90%) and extensive metabolism (>90%).

  9. Identification of polyproline II regions derived from the proline-rich nuclear receptor coactivators PNRC and PNRC2: new insights for ERα coactivator interactions.

    PubMed

    Byrne, C; Miclet, E; Broutin, I; Gallo, D; Pelekanou, V; Kampa, M; Castanas, E; Leclercq, G; Jacquot, Y

    2013-10-01

    Protein-protein interactions are crucial for signal transductions required for cell differentiation and proliferation. Their modulation is therefore key to the development of therapeutic alternatives, particularly in the context of cancer. According to literature data, the polyproline-rich nuclear receptor coactivators PNRC and PNRC2 interact with estrogen receptor (ERα) through their PxxP SH3-binding motifs. In a search to identify the molecular features governing this interaction, we explored using electronic circular dichroism (ECD) spectroscopy and molecular dynamics (MD) calculations, the capacity of a range of putative biologically active peptides derived from these proteins and containing this PxxP motif(s) to form polyproline II (PPII) domains. An additional more exhaustive structural study on a lead PPII peptide was also performed using 2D nuclear magnetic resonance (NMR) spectroscopy. With the exception of one of all the investigated peptides (PNRC-D), binding assays failed to detect any affinity for Grb2 SH3 domains, suggesting that PPII motifs issued from Grb2 antagonists have a binding mode distinct from those derived from Grb2 agonists. Instead, the peptides revealed a competitive binding ability against a synthetic peptide (ERα17p) with a putative PPII-cognate domain located within a coregulator recruitment region of ERα (AF-2 site). Our work, which constitutes the first structure-related interaction study concerning PNRC and PNRC2, supports not only the existence of PxxP-induced PPII sequences in these coregulators, but also confirms the presence of a PPII recognition site in the AF-2 of the steroid receptor ERα, a region important for transcription regulation. © 2013 Wiley Periodicals, Inc.

  10. Magnetic inclination shallowing problem and the issue of Eurasia's rigidity: insights following a palaeomagnetic study of upper Cretaceous basalts and redbeds from SE China

    NASA Astrophysics Data System (ADS)

    Li, Yong-Xiang; Shu, Liangshu; Wen, Bin; Yang, Zhenyu; Ali, Jason R.

    2013-09-01

    Redbeds are an important source of palaeomagnetic data, but they often record inclinations shallower than that of the ancient local geomagnetic field. Discrepancy of palaeopoles from Cretaceous redbeds in South China Block (SCB) and the coeval Eurasia reference pole is commonly attributed to inclination shallowing. However, redbed-derived palaeomagnetic data from the block have rarely been critically assessed with data from coeval volcanic rocks that should be unaffected by the problem. Here, we address the issue using high-quality palaeomagnetic data from Upper Cretaceous (˜95 Ma) amygdaloidal basalts and coeval redbeds from Jiangshan, Zhejiang Province and Guangfeng, Jiangxi Province. Stepwise thermal and alternating field demagnetizations isolated stable components that in the basalts are carried by a mixture of magnetite and titanomagntite and in the sedimentary units by haematite. The stable components are regarded as primary based on positive intraformational conglomerate tests and a regional tilt test. The redbeds yield a tilt corrected mean direction of D = 20.9°, I = 35.8°, α95 = 8.7°, N = 6, which is statistically indistinguishable from the mean direction of the basalts (D = 17.6°, I = 38.1°, α95 = 8.6°, N = 11), suggesting that the former do not suffer from the problem. In addition, analysis of the other Late Cretaceous SCB palaeopoles reveals two groups with one at relatively high (`H', ˜80°N) latitudes and the other at relatively low (`L', ˜70°N) latitudes. Importantly, each comprises palaeopoles from both redbeds and volcanic rocks, and reasonable consistency exists within each group, further attesting that SCB redbeds do not suffer significant inclination shallowing. Comparison of the SCB palaeopoles with a newly defined coeval reference pole for Europe indicates an ˜11° separation. Since inclination shallowing, over 1000 km tectonic shortening, and apparent polar wander appear unlikely, the ˜11° discrepancy may provide evidence for

  11. Nutrient limitation in three lowland tropical forests in southern China receiving high nitrogen deposition: insights from fine root responses to nutrient additions.

    PubMed

    Zhu, Feifei; Yoh, Muneoki; Gilliam, Frank S; Lu, Xiankai; Mo, Jiangming

    2013-01-01

    Elevated nitrogen (N) deposition to tropical forests may accelerate ecosystem phosphorus (P) limitation. This study examined responses of fine root biomass, nutrient concentrations, and acid phosphatase activity (APA) of bulk soil to five years of N and P additions in one old-growth and two younger lowland tropical forests in southern China. The old-growth forest had higher N capital than the two younger forests from long-term N accumulation. From February 2007 to July 2012, four experimental treatments were established at the following levels: Control, N-addition (150 kg N ha(-1) yr(-1)), P-addition (150 kg P ha(-1) yr(-1)) and N+P-addition (150 kg N ha(-1) yr(-1) plus 150 kg P ha(-1) yr(-1)). We hypothesized that fine root growth in the N-rich old-growth forest would be limited by P availability, and in the two younger forests would primarily respond to N additions due to large plant N demand. Results showed that five years of N addition significantly decreased live fine root biomass only in the old-growth forest (by 31%), but significantly elevated dead fine root biomass in all the three forests (by 64% to 101%), causing decreased live fine root proportion in the old-growth and the pine forests. P addition significantly increased live fine root biomass in all three forests (by 20% to 76%). The combined N and P treatment significantly increased live fine root biomass in the two younger forests but not in the old-growth forest. These results suggest that fine root growth in all three study forests appeared to be P-limited. This was further confirmed by current status of fine root N:P ratios, APA in bulk soil, and their responses to N and P treatments. Moreover, N addition significantly increased APA only in the old-growth forest, consistent with the conclusion that the old-growth forest was more P-limited than the younger forests.

  12. The first complete mitogenome of the South China deep-sea giant isopod Bathynomus sp. (Crustacea: Isopoda: Cirolanidae) allows insights into the early mitogenomic evolution of isopods.

    PubMed

    Shen, Yanjun; Kou, Qi; Zhong, Zaixuan; Li, Xinzheng; He, Lisheng; He, Shunping; Gan, Xiaoni

    2017-03-01

    In this study, the complete mitochondrial (mt) genome sequence of the South China deep-sea giant isopod Bathynomus sp. was determined, and this study is the first to explore in detail the mt genome of a deep-sea member of the order Isopoda. This species belongs to the genus Bathynomus, the members of which are saprophagous residents of the deep-sea benthic environment; based on their large size, Bathynomus is included in the "supergiant group" of isopods. The mt genome of Bathynomus sp. is 14,965 bp in length and consists of 13 protein-coding genes, two ribosomal RNA genes, only 18 transfer RNA genes, and a noncoding control region 362 bp in length, which is the smallest control region discovered in Isopoda to date. Although the overall genome organization is typical for metazoans, the mt genome of Bathynomus sp. shows a number of derived characters, such as an inversion of 10 genes when compared to the pancrustacean ground pattern. Rearrangements in some genes (e.g., cob, trnT, nad5, and trnF) are shared by nearly all isopod mt genomes analyzed thus far, and when compared to the putative isopod ground pattern, five rearrangements were found in Bathynomus sp. Two tRNAs exhibit modified secondary structures: The TΨC arm is absent from trnQ, and trnC lacks the DHU. Within the class Malacostraca, trnC arm loss is only found in other isopods. Phylogenetic analysis revealed that Bathynomus sp. (Cymothoida) and Sphaeroma serratum (Sphaeromatidea) form a single clade, although it is unclear whether Cymothoida is monophyletic or paraphyletic. Moreover, the evolutionary rate of Bathynomus sp. (dN/dS [nonsynonymous mutational rate/synonymous mutational rate] = 0.0705) is the slowest measured to date among Cymothoida, which may be associated with its relatively constant deep-sea environment. Overall, our results may provide useful information for understanding the evolution of deep-sea Isopoda species.

  13. Hydrothermal reequilibration of igneous magnetite in altered granitic plutons and its implications for magnetite classification schemes: Insights from the Handan-Xingtai iron district, North China Craton

    NASA Astrophysics Data System (ADS)

    Wen, Guang; Li, Jian-Wei; Hofstra, Albert H.; Koenig, Alan E.; Lowers, Heather A.; Adams, David

    2017-09-01

    Magnetite is a common mineral in igneous rocks and has been used as an important petrogenetic indicator as its compositions and textures reflect changing physiochemical parameters such as temperature, oxygen fugacity and melt compositions. In upper crustal settings, igneous rocks are often altered by hydrothermal fluids such that the original textures and compositions of igneous magnetite may be partly or completely obliterated, posing interpretive problems in petrological and geochemical studies. In this paper, we present textural and compositional data of magnetite from variably albitized granitoid rocks in the Handan-Xingtai district, North China Craton to characterize the hydrothermal reequilibration of igneous magnetite. Four types of magnetite have been identified in the samples studied: pristine igneous magnetite (type 1), reequilibrated porous magnetite (type 2), reequilibrated nonporous magnetite (type 3), and hydrothermal magnetite (type 4). Pristine igneous magnetite contains abundant well-developed ilmenite exsolution lamellae that are largely replaced by titanite during subsequent hydrothermal alteration. The titanite has a larger molar volume than its precursor ilmenite and thus causes micro-fractures in the host magnetite grains, facilitating dissolution and reprecipitation of magnetite. During sodic alteration, the igneous magnetite is extensively replaced by type 2 and type 3 magnetite via fluid-induced dissolution and reprecipitation. Porous type 2 magnetite is the initial replacement product of igneous magnetite and is subsequently replaced by the nonoporous type 3 variety as its surface area is reduced and compositional equilibrium with the altering fluid is achieved. Hydrothermal type 4 magnetite is generally euhedral and lacks exsolution lamellae and porosity, and is interpreted to precipitate directly from the ore-forming fluids. Hydrothermal reequilibration of igneous magnetite has led to progressive chemical purification, during which trace

  14. Source apportionment of PM2.5 at a regional background site in North China using PMF linked with radiocarbon analysis: insight into the contribution of biomass burning

    NASA Astrophysics Data System (ADS)

    Zong, Zheng; Wang, Xiaoping; Tian, Chongguo; Chen, Yingjun; Qu, Lin; Ji, Ling; Zhi, Guorui; Li, Jun; Zhang, Gan

    2016-09-01

    Source apportionment of fine particles (PM2.5) at a background site in North China in the winter of 2014 was done using statistical analysis, radiocarbon (14C) measurement and positive matrix factorization (PMF) modeling. Results showed that the concentration of PM2.5 was 77.6 ± 59.3 µg m-3, of which sulfate (SO42-) concentration was the highest, followed by nitrate (NO3-), organic carbon (OC), elemental carbon (EC) and ammonium (NH4+). As demonstrated by backward trajectory, more than half of the air masses during the sampling period were from the Beijing-Tianjin-Hebei (BTH) region, followed by Mongolia and the Shandong Peninsula. Cluster analysis of chemical species suggested an obvious signal of biomass burning in the PM2.5 from the Shandong Peninsula, while the PM2.5 from the BTH region showed a vehicle emission pattern. This finding was further confirmed by the 14C measurement of OC and EC in two merged samples. The 14C result indicated that biogenic and biomass burning emission contributed 59 ± 4 and 52 ± 2 % to OC and EC concentrations, respectively, when air masses originated from the Shandong Peninsula, while the contributions fell to 46 ± 4 and 38 ± 1 %, respectively, when the prevailing wind changed and came from the BTH region. The minimum deviation between source apportionment results from PMF and 14C measurement was adopted as the optimal choice of the model exercises. Here, two minor overestimates with the same range (3 %) implied that the PMF result provided a reasonable source apportionment of the regional PM2.5 in this study. Based on the PMF modeling, eight sources were identified; of these, coal combustion, biomass burning and vehicle emission were the main contributors of PM2.5, accounting for 29.6, 19.3 and 15.9 %, respectively. Compared with overall source apportionment, the contributions of vehicle emission, mineral dust, coal combustion and biomass burning increased when air masses came from the BTH region, Mongolia and the Shandong

  15. Crustal contamination versus an enriched mantle source for intracontinental mafic rocks: Insights from early Paleozoic mafic rocks of the South China Block

    NASA Astrophysics Data System (ADS)

    Xu, Wenjing; Xu, Xisheng; Zeng, Gang

    2017-08-01

    Several recent studies have documented that the silicic rocks (SiO2 > 65 wt.%) comprising Silicic Large Igneous Provinces are derived from partial melting of the crust facilitated by underplating/intraplating of ;hidden; large igneous province-scale basaltic magmas. The early Paleozoic intracontinental magmatic rocks in the South China Block (SCB) are dominantly granitoids, which cover a combined area of 22,000 km2. In contrast, exposures of mafic rocks total only 45 km2. These mafic rocks have extremely heterogeneous isotopic signatures that range from depleted to enriched (whole rock initial 87Sr/86Sr = 0.7041-0.7102; εNd(t) = - 8.4 to + 1.8; weighted mean zircon εHf(t) = - 7.4 to + 5.2), show low Ce/Pb and Nb/U ratios (0.59-13.1 and 3.5-20.9, respectively), and variable Th/La ratios (0.11-0.51). The high-MgO mafic rocks (MgO > 10 wt.%) tend to have lower εNd(t) values (<- 4) and Sm/Nd ratios (< 0.255), while the majority of the low-MgO mafic rocks (MgO < 10 wt.%) have higher εNd(t) values (>- 4) and Sm/Nd ratios (> 0.255). The differences in geochemistry between the high-MgO and low-MgO mafic rocks indicate greater modification of the compositions of high-MgO mafic magmas by crustal material. In addition, generally good negative correlations between εNd(t) and initial 87Sr/86Sr ratios, MgO, and K2O, along with the presence of inherited zircons in some plutons, indicate that the geochemical and isotopic compositions of the mafic rocks reflect significant crustal contamination, rather than an enriched mantle source. The results show that high-MgO mafic rocks with fertile isotopic compositions may be indicative of crustal contamination in addition to an enriched mantle source, and it is more likely that the lithospheric mantle beneath the SCB during the early Paleozoic was moderately depleted than enriched by ancient subduction processes.

  16. Sr-Nd-Pb isotopic compositions of the lower crust beneath northern Tarim: insights from igneous rocks in the Kuluketage area, NW China

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Wei, Xun; Xu, Yi-Gang; Long, Xiao-Ping; Shi, Xue-Fa; Zhao, Jian-Xin; Feng, Yue-Xing

    2016-09-01

    The composition of lower crust of the Tarim Craton in NW China is essential to understand the petrogenesis of the ~290-275 Ma Tarim basalts and associated intermediate-felsic rocks. However, it remains poorly constrained because extremely sparse granulite terrains or granulite xenoliths have been found in the Tarim Craton. New trace element and Sr-Nd-Pb isotopic data are reported for the Neoarchean and Neoproterozoic igneous rocks widely distributed in the northern margin of the Tarim Craton. The Neoarchean granitic gneisses show fractionated REE (rare earth element) patterns [(La/Yb) N = 12-58, YbN = 10.6-36] with pronounced negative Nb-Ta and Ti anomalies. These features, together with negative ɛNdi (-0.7 to -3.2) suggest that they were derived from melting of mafic lower crust. The Neoproterozoic biotite granodiorites are strongly depleted in HREE with (La/Yb) N up to 55. They are characterized by high Sr (671-789 ppm) but very low Y (7.10-8.06 ppm) and Yb contents (0.47-0.58 ppm), showing typical features of adakitic rocks. The samples with different SiO2 contents display identical 87Sr/86Sri (0.7101-0.7103), ɛNdi (-14.1 to -15.7) and Pb isotopes (208Pb/204Pbi = 36.94-37.07). These features together with arc-like trace element patterns suggest that they were derived from melting of thickened lower crust. In comparison, the Neoproterozoic hornblende-biotite granodiorites have similar trace element compositions except for weaker depletion in HREE and have lower 87Sr/86Sri (0.7078) and initial Pb isotopes, and higher ɛNdi (-12.3 to -12.7). This suggests that they were formed by melting of old lower continental crust at a shallower depth than the biotite granodiorites. These rocks were derived from the lower crust, thus providing valuable information on the nature of the lower crust beneath northern Tarim. Combined with published data, the 87Sr/86Sri, ɛNdi, 206Pb/204Pbi and ɛHfi of the northern Tarim lower crust ranges from 0.7055 to 0.7103, from -12 to -17

  17. Nutrient Limitation in Three Lowland Tropical Forests in Southern China Receiving High Nitrogen Deposition: Insights from Fine Root Responses to Nutrient Additions

    PubMed Central

    Zhu, Feifei; Yoh, Muneoki; Gilliam, Frank S.; Lu, Xiankai; Mo, Jiangming

    2013-01-01

    Elevated nitrogen (N) deposition to tropical forests may accelerate ecosystem phosphorus (P) limitation. This study examined responses of fine root biomass, nutrient concentrations, and acid phosphatase activity (APA) of bulk soil to five years of N and P additions in one old-growth and two younger lowland tropical forests in southern China. The old-growth forest had higher N capital than the two younger forests from long-term N accumulation. From February 2007 to July 2012, four experimental treatments were established at the following levels: Control, N-addition (150 kg N ha–1 yr–1), P-addition (150 kg P ha–1 yr–1) and N+P-addition (150 kg N ha–1 yr–1 plus 150 kg P ha–1 yr–1). We hypothesized that fine root growth in the N-rich old-growth forest would be limited by P availability, and in the two younger forests would primarily respond to N additions due to large plant N demand. Results showed that five years of N addition significantly decreased live fine root biomass only in the old-growth forest (by 31%), but significantly elevated dead fine root biomass in all the three forests (by 64% to 101%), causing decreased live fine root proportion in the old-growth and the pine forests. P addition significantly increased live fine root biomass in all three forests (by 20% to 76%). The combined N and P treatment significantly increased live fine root biomass in the two younger forests but not in the old-growth forest. These results suggest that fine root growth in all three study forests appeared to be P-limited. This was further confirmed by current status of fine root N:P ratios, APA in bulk soil, and their responses to N and P treatments. Moreover, N addition significantly increased APA only in the old-growth forest, consistent with the conclusion that the old-growth forest was more P-limited than the younger forests. PMID:24376562

  18. Sr-Nd-Pb isotopic compositions of the lower crust beneath northern Tarim: insights from igneous rocks in the Kuluketage area, NW China

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Wei, Xun; Xu, Yi-Gang; Long, Xiao-Ping; Shi, Xue-Fa; Zhao, Jian-Xin; Feng, Yue-Xing

    2017-04-01

    The composition of lower crust of the Tarim Craton in NW China is essential to understand the petrogenesis of the 290-275 Ma Tarim basalts and associated intermediate-felsic rocks. However, it remains poorly constrained because extremely sparse granulite terrains or granulite xenoliths have been found in the Tarim Craton. New trace element and Sr-Nd-Pb isotopic data are reported for the Neoarchean and Neoproterozoic igneous rocks widely distributed in the northern margin of the Tarim Craton. The Neoarchean granitic gneisses show fractionated REE (rare earth element) patterns [(La/Yb) N = 12-58, YbN = 10.6-36] with pronounced negative Nb-Ta and Ti anomalies. These features, together with negative ɛNdi (-0.7 to -3.2) suggest that they were derived from melting of mafic lower crust. The Neoproterozoic biotite granodiorites are strongly depleted in HREE with (La/Yb) N up to 55. They are characterized by high Sr (671-789 ppm) but very low Y (7.10-8.06 ppm) and Yb contents (0.47-0.58 ppm), showing typical features of adakitic rocks. The samples with different SiO2 contents display identical 87Sr/86Sri (0.7101-0.7103), ɛNdi (-14.1 to -15.7) and Pb isotopes (208Pb/204Pbi = 36.94-37.07). These features together with arc-like trace element patterns suggest that they were derived from melting of thickened lower crust. In comparison, the Neoproterozoic hornblende-biotite granodiorites have similar trace element compositions except for weaker depletion in HREE and have lower 87Sr/86Sri (0.7078) and initial Pb isotopes, and higher ɛNdi (-12.3 to -12.7). This suggests that they were formed by melting of old lower continental crust at a shallower depth than the biotite granodiorites. These rocks were derived from the lower crust, thus providing valuable information on the nature of the lower crust beneath northern Tarim. Combined with published data, the 87Sr/86Sri, ɛNdi, 206Pb/204Pbi and ɛHfi of the northern Tarim lower crust ranges from 0.7055 to 0.7103, from -12 to -17

  19. The closure of Palaeo-Tethys in the Sanjiang area, southwestern China: New insights from zircon U-Pb and Hf isotope data of granitoids

    NASA Astrophysics Data System (ADS)

    Dong, G.; Mo, X.; Wang, W.; Sun, Z.

    2016-12-01

    There are several granitoids associated with two sub-parallel suture zones in the Sanjiang area, southwestern China, which were interpreted to represent the magmatic expression of the tectonic evolution of Palaeo-Tethys during Late Palaeozoic to Early Mesozoic times. The granitoids are mainly peraluminous, high-K calc-alkaline with sub-parallel REE patterns and strong negative Eu anomalies, showing S-type characteristics. Recent geochronological and geochemical data of granotoids in the belts are adding some evidences on the Palaeo-Tethys evolution. Here we present new LA-ICP-MS ziron U-Pb ages and Hf isotopic data in the S type granitic intrusions from Lincang to Yacha to constrain on the times of the tectonic evolution. Measured ages of 200Ma - 230 Ma in the Lincang granite are equitant of the Wandashan granite (219Ma) and Yacha granite (220Ma) to the northern extension and granitic intrusions in eastern Myanmar (published ages of 210-220Ma) to the southern extension. There are also some I type granitoids (282-284 Ma) to the east in Jinghong and granodiorite (239 Ma) to the north in Baomaxueshan, which suggest the existence of island arc system and subduction setting. The occurrence of bimodal volcanism (Xiaodingxi Fm.) in Jinghong and middle Triassic andesite (Manghuai Fm.) with ages of 236-248 Ma supports this proposal. Thus, it has been confirmed that the S type granitoids from Lincang to Yacha formed under collsional setting during late Triassic period and the formation process lasted for 30 Ma approximately. Further, the new zircon Hf isotope data indicated that the granitoids should be formed by underlain Palaeoproterozoic crust with ɛHf model ages of 1900-2400 Ma. Therefore, the S type granitoids from Lincang to Yacha were formed during continental collision between the Baoshan-Gengma Terrane and the Lanping-Simao Terrane after subduction of the Paleo-Tethyan Oceanic Plate, which is suggesting the closure of the Paleo-Tethyan Ocean.

  20. Highly time-resolved urban aerosol characteristics during springtime in Yangtze River Delta, China: insights from soot particle aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Wang, Junfeng; Ge, Xinlei; Chen, Yanfang; Shen, Yafei; Zhang, Qi; Sun, Yele; Xu, Jianzhong; Ge, Shun; Yu, Huan; Chen, Mindong

    2016-07-01

    In this work, the Aerodyne soot particle - aerosol mass spectrometer (SP-AMS) was deployed for the first time during the spring of 2015 in urban Nanjing, a megacity in the Yangtze River Delta (YRD) of China, for online characterization of the submicron aerosols (PM1). The SP-AMS enables real-time and fast quantification of refractory black carbon (rBC) simultaneously with other non-refractory species (ammonium, sulfate, nitrate, chloride, and organics). The average PM1 concentration was found to be 28.2 µg m-3, with organics (45 %) as the most abundant component, following by sulfate (19.3 %), nitrate (13.6 %), ammonium (11.1 %), rBC (9.7 %), and chloride (1.3 %). These PM1 species together can reconstruct ˜ 44 % of the light extinction during this campaign based on the IMPROVE method. Chemically resolved mass-based size distributions revealed that small particles especially ultrafine ones (< 100 nm vacuum aerodynamic diameter) were dominated by organics and rBC, while large particles had significant contributions from secondary inorganic species. Source apportionment of organic aerosols (OA) yielded four OA subcomponents, including hydrocarbon-like OA (HOA), cooking-related OA (COA), semi-volatile oxygenated OA (SV-OOA), and low-volatility oxygenated OA (LV-OOA). Overall, secondary organic aerosol (SOA, equal to the sum of SV-OOA and LV-OOA) dominated the total OA mass (55.5 %), but primary organic aerosol (POA, equal to the sum of HOA and COA) can outweigh SOA in the early morning and evening due to enhanced human activities. High OA concentrations were often associated with high mass fractions of POA and rBC, indicating the important role of anthropogenic emissions during heavy pollution events. The diurnal cycles of nitrate, chloride, and SV-OOA both showed good anti-correlations with air temperatures, suggesting their variations were likely driven by thermodynamic equilibria and gas-to-particle partitioning. On the other hand, in contrast to other species

  1. Insights into aerosol chemistry during the 2015 China Victory Day parade: results from simultaneous measurements at ground level and 260 m in Beijing

    NASA Astrophysics Data System (ADS)

    Zhao, Jian; Du, Wei; Zhang, Yingjie; Wang, Qingqing; Chen, Chen; Xu, Weiqi; Han, Tingting; Wang, Yuying; Fu, Pingqing; Wang, Zifa; Li, Zhanqing; Sun, Yele

    2017-03-01

    Strict emission controls were implemented in Beijing and adjacent provinces to ensure good air quality during the 2015 China Victory Day parade. Here, we conducted synchronous measurements of submicron aerosols (PM1) at ground level and 260 m on a meteorological tower by using a high-resolution aerosol mass spectrometer and an aerosol chemical speciation monitor, respectively, in Beijing from 22 August to 30 September. Our results showed that the average PM1 concentrations are 19.3 and 14.8 µg m-3 at ground level and 260 m, respectively, during the control period (20 August-3 September), which are 57 and 50 % lower than those after the control period (4-30 September). Organic aerosols (OAs) dominated PM1 during the control period at both ground level and 260 m (55 and 53 %, respectively), while their contribution showed substantial decreases (˜ 40 %) associated with an increase in secondary inorganic aerosols (SIAs) after the parade, indicating a larger impact of emission controls on SIA than OA. Positive matrix factorization of OA further illustrated that primary OA (POA) showed similar decreases as secondary OA (SOA) at both ground level (40 % vs. 42 %) and 260 m (35 % vs. 36 %). However, we also observed significant changes in SOA composition at ground level. While the more oxidized SOA showed a large decrease by 75 %, the less oxidized SOA was comparable during (5.6 µg m-3) and after the control periods (6.5 µg m-3). Our results demonstrated that the changes in meteorological conditions and PM loadings have affected SOA formation mechanisms, and the photochemical production of fresh SOA was more important during the control period. By isolating the influences of meteorological conditions and footprint regions in polluted episodes, we found that regional emission controls on average reduced PM levels by 44-45 %, and the reductions were close among SIA, SOA and POA at 260 m, whereas primary species showed relatively more reductions (55-67 %) than secondary

  2. Outcome After Myocardial Infarction Treated With Resolute Integrity and Promus Element Stents: Insights From the DUTCH PEERS (TWENTE II) Randomized Trial.

    PubMed

    van Houwelingen, K Gert; Lam, Ming Kai; Löwik, Marije M; Danse, Peter W; Tjon Joe Gin, R Melvyn; Jessurun, Gillian A; Anthonio, Rutger L; Sen, Hanim; Linssen, Gerard C M; IJzerman, Maarten J; Doggen, Carine J M; von Birgelen, Clemens

    2016-12-01

    In acute myocardial infarction (MI), novel highly deliverable drug-eluting stents (DES) may be particularly valuable as their flexible stent designs might reduce device-induced traumas to culprit lesions. The aim of the study was to assess the safety and efficacy of percutaneous coronary interventions with 2 novel durable polymer-coated DES in patients with acute MI. The prospective, randomized DUTCH PEERS (TWENTE II) multicenter trial compares Resolute Integrity and Promus Element stents in 1811 all-comer patients, of whom 817 (45.1%) were treated for ST-segment elevation MI or non-ST-segment elevation MI and the 2-year outcome is available in 99.9%. The primary clinical endpoint is target vessel failure (TVF), a composite of cardiac death, target vessel related MI, or target vessel revascularization. Of all 817 patients treated for acute MI, 421 (51.5%) were treated with Resolute Integrity and 396 (48.5%) with Promus Element stents. At the 2-year follow-up, the rates of TVF (7.4% vs 6.1%; P = .45), target lesion revascularization (3.1% vs 2.8%; P = .79), and definite stent thrombosis (1.0% vs 0.5%; P = .69) were low for both stent groups. Consistent with these findings in all patients with acute MI, outcomes for the 2 DES were favorable and similar in both, with 370 patients with ST-segment elevation MI (TVF, 5.1% vs 4.9%; P = .81) and 447 patients with non-ST-segment elevation MI (TVF, 9.0% vs 7.5%; P = .56). Resolute Integrity and Promus Element stents were both safe and efficacious in treating patients with acute MI. The present 2-year follow-up data underline the safety of using these devices in this particular clinical setting. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  3. Sequence analysis and structure prediction of type II Pseudomonas sp. USM 4–55 PHA synthase and an insight into its catalytic mechanism

    PubMed Central

    Wahab, Habibah A; Ahmad Khairudin, Nurul Bahiyah; Samian, Mohd Razip; Najimudin, Nazalan

    2006-01-01

    Background Polyhydroxyalkanoates (PHA), are biodegradable polyesters derived from many microorganisms such as the pseudomonads. These polyesters are in great demand especially in the packaging industries, the medical line as well as the paint industries. The enzyme responsible in catalyzing the formation of PHA is PHA synthase. Due to the limited structural information, its functional properties including catalysis are lacking. Therefore, this study seeks to investigate the structural properties as well as its catalytic mechanism by predicting the three-dimensional (3D) model of the Type II Pseudomonas sp. USM 4–55 PHA synthase 1 (PhaC1P.sp USM 4–55). Results Sequence analysis demonstrated that PhaC1P.sp USM 4–55 lacked similarity with all known structures in databases. PSI-BLAST and HMM Superfamily analyses demonstrated that this enzyme belongs to the alpha/beta hydrolase fold family. Threading approach revealed that the most suitable template to use was the human gastric lipase (PDB ID: 1HLG). The superimposition of the predicted PhaC1P.sp USM 4–55 model with 1HLG covering 86.2% of the backbone atoms showed an RMSD of 1.15 Å. The catalytic residues comprising of Cys296, Asp451 and His479 were found to be conserved and located adjacent to each other. In addition to this, an extension to the catalytic mechanism was also proposed whereby two tetrahedral intermediates were believed to form during the PHA biosynthesis. These transition state intermediates were further postulated to be stabilized by the formation of oxyanion holes. Based on the sequence analysis and the deduced model, Ser297 was postulated to contribute to the formation of the oxyanion hole. Conclusion The 3D model of the core region of PhaC1P.sp USM 4–55 from residue 267 to residue 484 was developed using computational techniques and the locations of the catalytic residues were identified. Results from this study for the first time highlighted Ser297 potentially playing an important role in

  4. Modification of an ancient subcontinental lithospheric mantle by continental subduction: Insight from the Maowu garnet peridotites in the Dabie UHP belt, eastern China

    NASA Astrophysics Data System (ADS)

    Chen, Yi; Su, Bin; Chu, Zhuyin

    2017-05-01

    Orogenic mantle-derived peridotites commonly originate from the subcontinental lithospheric mantle (SCLM) and thus provide a key target to investigate the modification of the SCLM by a subducting slab. The Maowu ultramafic rocks from the Dabie ultrahigh-pressure (UHP) metamorphic belt have formerly been debated as representing cumulates or mantle-derived peridotites. Detailed petrological and geochemical data presented in this study provide new constraints on the origin and formation of the peridotites involving melt depletion in the ancient SCLM and deep crustal metasomatism. The Maowu garnet dunites have refractory bulk compositions characterized by high Mg# (91.9-92.0) and Ni (2537-2892 ppm) values and low Al2O3 (0.26-0.76 wt.%), CaO (0.05-0.32 wt.%), TiO2 (< 0.03 wt.%), Pd/Ir (0.40-0.46) and 187Os/188Os (minimum 0.11461) values. The Paleoproterozoic model ages (TRD = 2.1 Ga, TMA = 2.3 Ga) of the most refractory dunites represent minimum estimates for the age of the initial melt extraction. The extremely depleted nature, high olivine Fo (92.7-93.9), high Cr# (82-87) of spinel, and Re-Os isotopic data suggest that the Maowu garnet dunites are the residues of 40% partial melting and represent a Paleoproterozoic fragment of the SCLM beneath the southeastern margin of the North China craton. Many garnet orthopyroxenite veins crosscutting the Maowu dunites preserve abundant metasomatic textures and show variable enrichment in incompatible elements. Mineral and whole-rock chemistry indicate that these veins represent metasomatic products between the wall dunites and silica-rich hydrous melts under UHP conditions. The veins show large variations in platinum-group element (PGE) signatures and Re-Os isotopes. The garnet-poor orthopyroxenite veins are characterized by low Al2O3 (< 2 wt.%) and S (< 31 ppm) contents and have PGE patterns and 187Os/188Os ratios similar to the wall dunites, whereas the garnet-rich orthopyroxenite veins have high Al2O3 (> 6 wt.%) and S (99

  5. A westward propagating slab tear model for Late Triassic Qinling Orogenic Belt geodynamic evolution: Insights from the petrogenesis of the Caoping and Shahewan intrusions, central China

    NASA Astrophysics Data System (ADS)

    Hu, Fangyang; Liu, Shuwen; Zhang, Wanyi; Deng, Zhengbin; Chen, Xu

    2016-10-01

    Late Triassic granitoid intrusions are widespread in the South Qinling Belt (SQB), providing excellent subjects to understand the geodynamic evolution of the Qinling Orogenic Belt and the collision between the North China Craton (NCC) and Yangtze Craton (YZC). This study shows newly obtained geological, geochemical and zircon U-Pb-Hf isotopic data of the Caoping and Shahewan intrusions, revealing that the Caoping intrusion consists of 215 Ma fined-grained granites, and 221-215 Ma porphyritic and coarse to medium-grained tonalites, granodiorites and monzogranites, which assemble with coeval mafic magmatic enclaves (MMEs). The Shahewan intrusion is composed of 215-210 Ma porphyritic granodiorites and monzogranites, which also assemble with coeval MMEs. The fine-grained granites from the Caoping intrusion are characterized by high SiO2, Rb and (La/Yb)N ratio, but low MgO, CaO and Sc contents, with εHf(t) values of - 8.6 to + 4.3 and TDM2(Hf) ages of 883-1596 Ma, suggesting that they are mainly derived from partial melting of the Meso- to Neoproterozoic metagreywackes. The porphyritic and coarse to medium-grained granitoid rocks from both Caoping and Shahewan intrusions are characterized by higher MgO, CaO, Sc, Mg# values, but low SiO2, Rb contents and (La/Yb)N ratio, with εHf(t) values of - 0.7 to + 2.8 and TDM2(Hf) values of 961-1158 Ma, suggesting that they are mainly formed by magma mixing between melts that were derived from Meso- to Neoproterozoic basement rocks of the SQB and metasomatized lithospheric mantle. The MMEs from Caoping and Shahewan intrusions are characterized by low SiO2, Sr/Y ratio, high MgO, K2O, Rb, Sc, total REE contents, with εHf(t) values of + 0.5 to + 6.1 and TDM(Hf) values of 661-846 Ma, suggesting that they are produced by partial melting of metasomatized lithospheric mantle. The rapakivi-like textures of the rocks from Shahewan intrusion may be caused by continued underplating and injection of mafic magma resulting in higher

  6. New insights into PM2.5 chemical composition and sources in two major cities in China during extreme haze events using aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Elser, M.; Huang, R.-J.; Wolf, R.; Slowik, J. G.; Wang, Q.-Y.; Canonaco, F.; Li, G. H.; Bozzetti, C.; Daellenbach, K. R.; Huang, Y.; Zhang, R.-J.; Li, Z.-Q.; Cao, J. J.; Baltensperger, U.; El-Haddad, I.; Prévôt, A. S. H.

    2015-11-01

    During winter 2013-2014 aerosol mass spectrometer (AMS) measurements were conducted for the first time with a novel PM2.5 (particulate matter with aerodynamic diameter ≤ 2.5 μm) lens in two major cities of China: Xi'an and Beijing. We denote the periods with visibility below 2 km as extreme haze and refer to the rest as reference periods. During the measurements in Xi'an an extreme haze covered the city for about a week and the total non-refractory (NR)-PM2.5 mass fraction reached peak concentrations of over 1000 μg m-3. During the measurements in Beijing two extreme haze events occurred, but the temporal extent and the total concentrations reached during these events were lower than in Xi'an. Average PM2.5 concentrations of 537 ± 146 μg m-3 and 243 ± 47 μg m-3 (including NR species and equivalent black carbon, eBC) were recorded during the extreme haze events in Xi'an and Beijing, respectively. During the reference periods the measured average concentrations were 140 ± 99 μg m-3 in Xi'an and 75 ± 61 μg m-3 in Beijing. The relative composition of the NR-PM2.5 evolved substantially during the extreme haze periods, with increased contributions of the inorganic components (mostly sulfate and nitrate). Our results suggest that the high relative humidity present during the extreme haze events had a strong effect on the increase of sulfate mass (via aqueous phase oxidation of sulfur dioxide). Another relevant characteristic of the extreme haze is the size of the measured particles. During the extreme haze events, the AMS showed much larger particles, with a volume weighted mode at about 800 to 1000 nm, in contrast to about 400 nm during reference periods. These large particle sizes made the use of the PM2.5 inlet crucial, especially during the severe haze events, where 39 ± 5 % of the mass would have been lost in the conventional PM1 (particulate matter with aerodynamic diameter ≤ 1 μm) inlet. A novel positive matrix factorization procedure was developed

  7. Investigation of risk factors of psychological acceptance and burnout syndrome among nurses in China.

    PubMed

    Yao, Yongcheng; Yao, Wu; Wang, Wei; Li, Hong; Lan, Yajia

    2013-10-01

    The objectives of this study were to determine reliability of Chinese version of Acceptance and Action Questionnaire-II (AAQ-II), the relationship between psychological acceptance (PA), and burnout syndrome and their risk factors among nurses in China. The reliability of AAQ-II in Chinese was evaluated first by testing on 111 doctors and 108 nurses in China. On the number of 845 nurses selected from nine city hospitals by using stratified cluster sampling method, the Maslach Burnout Inventory-General Survey was administered to establish the presence of burnout, and the AAQ-II was used to measure their PA. Results showed that the AAQ-II in Chinese had a good test-retest reliability. PA was statistically significantly negatively correlated to the three dimensionalities of burnout among nurses in China. Male and female nurses had a significant difference in PA. Risk factors for burnout were age (25-44 years), marital status (married), gender (male), hospital department (emergency) and position (primary title) as well as PA. The findings provide insights into the risk factors of burnout in Chinese nurses and may have clinical implications in preventing burnout in Chinese nurses.

  8. Solid state and dynamic solution structures of O-carbamidine amidoximes gives further insight into the mechanism of zinc(II)-mediated generation of 1,2,4-oxadiazoles

    NASA Astrophysics Data System (ADS)

    Kulish, Kirill I.; Novikov, Alexander S.; Tolstoy, Peter M.; Bolotin, Dmitrii S.; Bokach, Nadezhda A.; Zolotarev, Andrey A.; Kukushkin, Vadim Yu.

    2016-05-01

    Three new iminium salts [H2Ndbnd C(R)ONdbnd C(R‧)NH2](p-TolSO3)·½H2O ([1-3](p-TolSO3)·½H2O; R/R‧ = NMe2/PhCH21, NMe2/p-BrC6H42, N(CH2)5/p-BrC6H43) were synthesized via ZnII-mediated amidoxime-cyanamide coupling and their solid structures were studied by X-ray diffraction. Solution structure and conformational changes of [1-3](p-TolSO3)·½H2O were studied by dynamic NMR. The obtained quantitative data were supported by DFT calculations. All the obtained results help to understand the relative stability of the salts [H2Ndbnd C(R)ONdbnd C(R‧)NH2](X) (R = NAlk2, Alk, Ar) and give a further insight into the mechanism of ZnII-mediated generation of 1,2,4-oxadiazoles. The electron delocalization and sesquialteral bonds in the [H2Ndbnd C(NR2)ONdbnd C(R‧)NH2]+ system was recognized by estimation of values of activation energy barriers (14-18 kcal/mol by DNMR and 16-17 kcal/mol by DFT calculations) for the rotation around the CN bonds for the NR2 groups and inspection of the solid-state X-ray data along with the Wiberg bond indices (intermediate single/double bond order for the CN distances). This electron delocalization is responsible for the stabilization of the positively charged iminium cation. The moderate strength hydrogen bonding between the oxime N atom and the =NH2 group, which is verified from the X-ray, DNMR experiments, and by using quantum chemical calculations, stabilizes the iminium salt, but it is still weak to prevent the heterocyclization. Theoretical calculations of the heterocyclization of [H2Ndbnd C(R)ONdbnd C(R‧)NH2]+ to 1,2,4-oxadiazoles demonstrated that it is kinetically hindered to a greater extent for R = NAlk2 and this explains their lower reactivity as compared to the iminium salts with R = Alk, Ar.

  9. Our China Policy: The Need for Change.

    ERIC Educational Resources Information Center

    Barnett, A. Doak

    This critical analysis of Sino-American relations reviews historical events since World War II, summarizes United States policy toward the Peoples Republic of China and contends that improved relations with China should be a goal. Review of Communist China's activities reveals that: 1) an aim seems to be to expand power and influence but not…

  10. Our China Policy: The Need for Change.

    ERIC Educational Resources Information Center

    Barnett, A. Doak

    This critical analysis of Sino-American relations reviews historical events since World War II, summarizes United States policy toward the Peoples Republic of China and contends that improved relations with China should be a goal. Review of Communist China's activities reveals that: 1) an aim seems to be to expand power and influence but not…

  11. Indications for Three Independent Domestication Events for the Tea Plant (Camellia sinensis (L.) O. Kuntze) and New Insights into the Origin of Tea Germplasm in China and India Revealed by Nuclear Microsatellites.

    PubMed

    Meegahakumbura, M K; Wambulwa, M C; Thapa, K K; Li, M M; Möller, M; Xu, J C; Yang, J B; Liu, B Y; Ranjitkar, S; Liu, J; Li, D Z; Gao, L M

    2016-01-01

    Tea is the world's most popular non-alcoholic beverage. China and India are known to be the largest tea producing countries and recognized as the centers for the domestication of the tea plant (Camellia sinensis (L.) O. Kuntze). However, molecular studies on the origin, domestication and relationships of the main teas, China type, Assam type and Cambod type are lacking. Twenty-three nuclear microsatellite markers were used to investigate the genetic diversity, relatedness, and domestication history of cultivated tea in both China and India. Based on a total of 392 samples, high levels of genetic diversity were observed for all tea types in both countries. The cultivars clustered into three distinct genetic groups (i.e. China tea, Chinese Assam tea and Indian Assam tea) based on STRUCTURE, PCoA and UPGMA analyses with significant pairwise genetic differentiation, corresponding well with their geographical distribution. A high proportion (30%) of the studied tea samples were shown to possess genetic admixtures of different tea types suggesting a hybrid origin for these samples, including the Cambod type. We demonstrate that Chinese Assam tea is a distinct genetic lineage from Indian Assam tea, and that China tea sampled from India was likely introduced from China directly. Our results further indicate that China type tea, Chinese Assam type tea and Indian Assam type tea are likely the result of three independent domestication events from three separate regions across China and India. Our findings have important implications for the conservation of genetic stocks, as well as future breeding programs.

  12. Genetic and geographical structure of boreal plants in their southern range: phylogeography of Hippuris vulgaris in China.

    PubMed

    Lu, Qixiang; Zhu, Jinning; Yu, Dan; Xu, Xinwei

    2016-02-09

    Our current understanding of the evolutionary history of boreal and arctic-alpine plants in their southern range in Asia remains relatively poor. Using three cpDNA non-coding regions and nine nuclear microsatellite (nSSR) loci, we examine the phylogeographic pattern in a broad geographic sampling of the boreal plant Hippuris vulgaris to infer its dispersal and diversification in China. In addition, the species distributions at the Last Glacial Maximum (LGM) and at present were predicted using ecological niche modeling (ENM). The cpDNA results revealed two distinct lineages, A and B. A is restricted to Northeast China; B is distributed in Northwest China, the Qinghai-Tibet Plateau (QTP) and North and Northeast (NNE) China; and A and B diverged ca. 1.36 Ma. The nSSR data revealed two genetic clusters corresponding to the two cpDNA lineages and nonreciprocal hybridization with lineage A as the maternal lineage in Northeast China. Cluster B further divided into three subclusters: I, mainly in NNE China and the northeastern border of the QTP; II, in Northwest China and the QTP; and III, on the QTP. ENM predicted a marked range shift on the QTP at the LGM, retreating from the platform to the northeast and southeast edges. Hippuris vulgaris probably diverged into lineages A and B in high latitudes and then immigrated into Northeast China and Northwest China, respectively. Lineage A persisted and diversified in Northeast China. Lineage B reached the QTP during the mid-Pleistocene, diversified in that region due to the influence of climatic oscillations, migrated into Northeast China and subsequently hybridized with lineage A. Our findings give empirical evidence that boreal plants display complex evolutionary history in their southern range in Asia and provide new insights into the evolution of boreal and arctic-alpine plants.

  13. Deconstructing insight: EEG correlates of insightful problem solving.

    PubMed

    Sandkühler, Simone; Bhattacharya, Joydeep

    2008-01-23

    Cognitive insight phenomenon lies at the core of numerous discoveries. Behavioral research indicates four salient features of insightful problem solving: (i) mental impasse, followed by (ii) restructuring of the problem representation, which leads to (iii) a deeper understanding of the problem, and finally culminates in (iv) an "Aha!" feeling of suddenness and obviousness of the solution. However, until now no efforts have been made to investigate the neural mechanisms of these constituent features of insight in a unified framework. In an electroencephalographic study using verbal remote associate problems, we identified neural correlates of these four features of insightful problem solving. Hints were provided for unsolved problems or after mental impasse. Subjective ratings of the restructuring process and the feeling of suddenness were obtained on trial-by-trial basis. A negative correlation was found between these two ratings indicating that sudden insightful solutions, where restructuring is a key feature, involve automatic, subconscious recombination of information. Electroencephalogram signals were analyzed in the space x time x frequency domain with a nonparametric cluster randomization test. First, we found strong gamma band responses at parieto-occipital regions which we interpreted as (i) an adjustment of selective attention (leading to a mental impasse or to a correct solution depending on the gamma band power level) and (ii) encoding and retrieval processes for the emergence of spontaneous new solutions. Secondly, we observed an increased upper alpha band response in right temporal regions (suggesting active suppression of weakly activated solution relevant information) for initially unsuccessful trials that after hint presentation led to a correct solution. Finally, for trials with high restructuring, decreased alpha power (suggesting greater cortical excitation) was observed in right prefrontal area. Our results provide a first account of cognitive

  14. Antithrombin Cambridge II(A384S) mutation frequency and antithrombin activity levels in 120 of deep venous thrombosis and 150 of cerebral infarction patients in a single center in Southern China.

    PubMed

    Zhang, Guang-sen; Tang, Yang-ming; Tang, Mei-qing; Qing, Zi-Ju; Shu, Chang; Tang, Xiang-qi; Deng, Ming-yang; Tan, Li-ming

    2010-09-01

    Antithrombin Cambridge II(A384S) mutation shows a relatively high frequency in western population. Some studies suggest that the mutation is an independent genetic risk factor both for deep vein thrombosis (DVT) and for arterial thrombosis, but whether the mutation has racial difference or has a general significance for thrombophilia remains unclear. In this study we performed an analysis of the prevalence of the mutation in Chinese southern population; Also, the antithrombin activity levels were evaluated in each investigated individual. The studies included 120 patients with DVT, 150 patients with cerebral infarction, and 110 controls. The mutation was detected using polymerase chain reaction/PvuII restrictive fragment length polymorphism procedures. Antithrombin activity assay was done using chromogenic substrate method. The results showed that no antithrombin Cambridge II mutation was detected in all three groups (DVT, cerebral infarction and controls), the incidence was 0/380. Plasma antithrombin activity was 91.37% +/- 16.15% in the DVT patients and 102.68% +/- 13.10% in the controls; the antithrombin activity was significantly reduced in the DVT group (P < 0.0001). In DVT patients, eight cases were identified as primary antithrombin deficiency, accounting for an incidence of 6.7%. No significant difference was found for antithrombin activity between cerebral infarction group and controls. These results suggest that antithrombin Cambridge II mutation has a racial difference, and may not be a valuable risk factor of thrombophilia in Asian population, and antithrombin deficiency remains a major genetic risk factor for DVT patients in China.

  15. [PS II photochemical efficiency in flag leaf of wheat varieties and its adaptation to strong sun- light intensity on farmland of Xiangride in Qinghai Province, Northwest China].

    PubMed

    Shi, Sheng-Bo; Chen, Wen-Jie; Shi, Rui; Li, Miao; Zhang, Huai-Gang; Sun, Ya-Nan

    2014-09-01

    Taking four wheat varieties developed by Northwest Institute of Plateau Biology, Chinese Academy of Sciences, as test materials, with the measurement of content of photosynthetic pigments, leaf area, fresh and dry mass of flag leaf, the PS II photochemistry efficiency of abaxial and adaxial surface of flag leaf and its adaptation to strong solar radiation during the period of heading stage in Xiangride region were investigated with the pulse-modulated in-vivo chlorophyll fluorescence technique. The results indicated that flag leaf angle mainly grew in horizontal state in Gaoyuan 314, Gaoyuan 363 and Gaoyuan 584, and mainly in vertical state in Gaoyuan 913 because of its smaller leaf area and larger width. Photosynthetic pigments were different among the 4 varieties, and positively correlated with intrinsic PS II photochemistry efficiencies (Fv/Fm). In clear days, especially at noon, the photosynthetic photoinhibition was more serious in abaxial surface of flag leaf due to directly facing the solar radiation, but it could recover after reduction of sunlight intensity in the afternoon, which meant that no inactive damage happened in PS II reaction centers. There were significant differences of PS II actual and maximum photochemical efficiencies at the actinic light intensity (ΦPS II and Fv'/Fm') between abaxial and adaxial surface, and their relative variation trends were on the contrary. The photochemical and non-photochemical quenching coefficients (qP and NPQ) had a similar tendency in both abaxial and adaxial surfaces. Although ΦPS II and qP were lower in adaxial surface of flag leaf, the Fv'/Fm' was significantly higher, which indicated that the potential PS II capture efficiency of excited energy was higher. The results demonstrated that process of photochemical and non-photochemical quenching could effectively dissipate excited energy caused by strong solar radiation, and there were higher adaptation capacities in wheat varieties natively cultivated in

  16. Indications for Three Independent Domestication Events for the Tea Plant (Camellia sinensis (L.) O. Kuntze) and New Insights into the Origin of Tea Germplasm in China and India Revealed by Nuclear Microsatellites

    PubMed Central

    Meegahakumbura, M. K.; Wambulwa, M. C.; Thapa, K. K.; Li, M. M.; Möller, M.; Xu, J. C.; Yang, J. B.; Liu, B. Y.; Ranjitkar, S.; Liu, J.; Li, D. Z.; Gao, L. M.

    2016-01-01

    Background Tea is the world’s most popular non-alcoholic beverage. China and India are known to be the largest tea producing countries and recognized as the centers for the domestication of the tea plant (Camellia sinensis (L.) O. Kuntze). However, molecular studies on the origin, domestication and relationships of the main teas, China type, Assam type and Cambod type are lacking. Methodology/Principal Findings Twenty-three nuclear microsatellite markers were used to investigate the genetic diversity, relatedness, and domestication history of cultivated tea in both China and India. Based on a total of 392 samples, high levels of genetic diversity were observed for all tea types in both countries. The cultivars clustered into three distinct genetic groups (i.e. China tea, Chinese Assam tea and Indian Assam tea) based on STRUCTURE, PCoA and UPGMA analyses with significant pairwise genetic differentiation, corresponding well with their geographical distribution. A high proportion (30%) of the studied tea samples were shown to possess genetic admixtures of different tea types suggesting a hybrid origin for these samples, including the Cambod type. Conclusions We demonstrate that Chinese Assam tea is a distinct genetic lineage from Indian Assam tea, and that China tea sampled from India was likely introduced from China directly. Our results further indicate that China type tea, Chinese Assam type tea and Indian Assam type tea are likely the result of three independent domestication events from three separate regions across China and India. Our findings have important implications for the conservation of genetic stocks, as well as future breeding programs. PMID:27218820

  17. Review of beetle forewing structures and their biomimetic applications in China: (II) On the three-dimensional structure, modeling and imitation.

    PubMed

    Chen, Jinxiang; Zu, Qiao; Wu, Gang; Xie, Juan; Tuo, Wanyong

    2015-10-01

    This paper reviews the research progress made in China regarding the microstructure of the forewing trabeculae, their anti-peeling and anti-collisional mechanical properties, the three-dimensional (3D) microstructures of the forewings, their modeling, and their mechanical properties. We focus on 1) the distribution of the trabeculae in two types of beetles with a six-fold difference in density, the structure of the trabeculae and a proposed 3D model with an integrated trabeculae-honeycomb structure; 2) finite element analyses and experimental results showing that the average anti-peeling strength in the presence of trabeculae can be as much as approximately three-fold greater than that in the absence of trabeculae; 3) the strengthening mechanisms of these structures and describe an optimized double thin-walled biomimetic structure that possesses excellent absorption and buffering properties; 4) the development of technologies to produce fully integrated honeycomb plates with short fibers as a reinforced composite material and the verification that these plates are strong and lightweight and exhibit good integrity. Finally, we note the shortcomings in China in this field of research and propose possible future research directions in the field of biomimetic functional materials.

  18. Interventional Radiology in China

    SciTech Connect

    Teng Gaojun Xu Ke; Ni Caifang; Li Linsun

    2008-03-15

    With more than 3000 members, the Chinese Society of Interventional Radiology (CSIR) is one of the world's largest societies for interventional radiology (IR). Nevertheless, compared to other societies such as CIRSE and SIR, the CSIR is a relatively young society. In this article, the status of IR in China is described, which includes IR history, structure and patient management, personnel, fellowship, training, modalities, procedures, research, turf battle, and insightful visions for IR from Chinese interventional radiologists.

  19. Health care in China.

    PubMed

    Brown, M S; Burns, C E; Hellings, P J

    1984-05-01

    Maternal-child nurses are part of a growing number of Americans who have had the opportunity to visit China. An increased understanding of the history and of the health care practices of the Chinese people lends itself to an examination of American values and health practices. The insight developed may aid us as we seek to understand our own health care practices for women and children and to plan for the future in health care.

  20. Design at the Edge of the World: The Birth of American Air Intelligence in the China, Burma, India, and the Pacific Theaters during World War II

    DTIC Science & Technology

    2017-06-01

    principles for air intelligence which remains relevant to this day. The successes of Fifth and Fourteenth Air Force, and later Tenth Air Force...Pacific developed some of the most successful , as well as the most disappointing, intelligence operations in World War II. The limited resources...each Air Force organized its intelligence operations largely determined the Air Force’s success . The intelligence experience in the CBI and Pacific

  1. Characterizing and sourcing ambient PM2.5 over key emission regions in China II: Organic molecular markers and CMB modeling

    NASA Astrophysics Data System (ADS)

    Zhou, Jiabin; Xiong, Ying; Xing, Zhenyu; Deng, Junjun; Du, Ke

    2017-08-01

    From November 2012 to July 2013, a sampling campaign was completed for comprehensive characterization of PM2.5 over four key emission regions in China: Beijing-Tianjin-Hebei (BTH), Yangzi River Delta (YRD), Pearl River Delta (PRD), and Sichuan Basin (SB). A multi-method approach, adopting different analytical and receptor modeling methods, was employed to determine the relative abundances of region-specific air pollution constituents and contributions of emission sources. This paper is focused on organic molecular marker based source apportionment using chemical mass balance (CMB) receptor modeling. Analyses of the organic molecular markers revealed that vehicle emission, coal combustion, biomass burning, meat cooking and natural gas combustion were the major contributors to organic carbon (OC) in PM2.5. The vehicle emission dominated the sources contributing to OC in spring at four sampling sites. During wintertime, the coal combustion had highest contribution to OC at BTH site, while the major source contributing to OC at YRD and PRD sites was vehicle emission. In addition, the relative contributions of different emission sources to PM2.5 mass at a specific location site and in a specific season revealed seasonal and spatial variations across all four sampling locations. The largest contributor to PM2.5 mass was secondary sulfate (14-17%) in winter at the four sites. The vehicle emission was found to be the major source (14-21%) for PM2.5 mass at PRD site. The secondary ammonium has minor variation (4-5%) across the sites, confirming the influences of regional emission sources on these sites. The distinct patterns of seasonal and spatial variations of source apportionment observed in this study were consistent with the findings in our previous paper based upon water-soluble ions and carbonaceous fractions. This makes it essential for the local government to make season- and region-specific mitigation strategies for abating PM2.5 pollution in China.

  2. Activity measurements of the radionuclide 99mTc for the NIM, China in the ongoing comparison BIPM.RI(II)-K4.Tc-99m

    NASA Astrophysics Data System (ADS)

    Michotte, C.; Nonis, M.; Liang, J. C.; Chen, J.; Liu, H. R.; Zhang, M.; Zhao, Q.; Yang, Y. D.

    2013-01-01

    In 2012, the fourth comparison of activity measurements of 99mTc using the Transfer Instrument of the International Reference System (SIRTI) took place at the Chinese National Institute of Metrology (NIM). An ampoule containing about 70 kBq of 99mTc traceable to the NIM primary standard was measured in the SIRTI for more than three half-lives. The comparison, identifier BIPM.RI(II)-K4.Tc-99m, is linked to the BIPM.RI(II)-K1.Tc-99m comparison and the degrees of equivalence with the key comparison reference value and between the present NIM result, the other K4 participant and the six participants in the K1 comparison have been evaluated. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  3. FBIS report. Science and technology: China, March 15, 1996

    SciTech Connect

    1996-03-15

    ;Partial Contents: Science And Technology (China: Feature on CAS Qingdao Marine Research Institute); Computers (China: CASC Institute Imports GTS-3000 Automatic Test Equipment From Grumman in U.S., China: YH-II Supercommuter System Applications Value Nears 10 Billion RMB); Defense Technology (China: 3-D Terrain Visualizaton Model Based on Fractal Interpolation, Delaunay Triangulation, China Develops New Technique for Processing Highly Radioactive Liquid Wastes); Microelectronics (China: Further Details on Huajing Group`s Project 908 (Submicron Development Plan) Released); Physics (Advances in China`s Seismological Observation Technology, China: Photoreport on High-Power Laser Physics Apparatus); National Energy Developments (China: Current Situation of Development of Rural Energy Industry); Oil And Gas (Foreland Basins and Their Hydrocarbon Potential in China); Nuclear Power (Taiwan: Incident Report on TaiPower`s No. 2 Nuclear Power Plant).

  4. China Report, Economic Affairs.

    DTIC Science & Technology

    1986-02-14

    the Dandong Harbor in Dandong. Completion of these two ports will greatly improve the traffic and transport services of Jinzhou and Dandong. 37 5...consumption by means of technical improve - ments, rational utilization, scientific control , and rationalization of the economic structure. Ch II...make greater efforts to fight smuggling and improve control of foreign exchange. China plans to add 5 ’million kw of power-generating capacity this

  5. Application of 'Six Sigma{sup TM}' and 'Design of Experiment' for Cementation - Recipe Development for Evaporator Concentrate for NPP Ling AO, Phase II (China) - 12555

    SciTech Connect

    Fehrmann, Henning; Perdue, Robert

    2012-07-01

    Cementation of radioactive waste is a common technology. The waste is mixed with cement and water and forms a stable, solid block. The physical properties like compression strength or low leach ability depends strongly on the cement recipe. Due to the fact that this waste cement mixture has to fulfill special requirements, a recipe development is necessary. The Six Sigma{sup TM}' DMAIC methodology, together with the Design of experiment (DoE) approach, was employed to optimize the process of a recipe development for cementation at the Ling Ao nuclear power plant (NPP) in China. The DMAIC offers a structured, systematical and traceable process to derive test parameters. The DoE test plans and statistical analysis is efficient regarding the amount of test runs and the benefit gain by getting a transfer function. A transfer function enables simulation which is useful to optimize the later process and being responsive to changes. The DoE method was successfully applied for developing a cementation recipe for both evaporator concentrate and resin waste in the plant. The key input parameters were determined, evaluated and the control of these parameters were included into the design. The applied Six Sigma{sup TM} tools can help to organize the thinking during the engineering process. Data are organized and clearly presented. Various variables can be limited to the most important ones. The Six Sigma{sup TM} tools help to make the thinking and decision process trace able. The tools can help to make data driven decisions (e.g. C and E Matrix). But the tools are not the only golden way. Results from scoring tools like the C and E Matrix need close review before using them. The DoE is an effective tool for generating test plans. DoE can be used with a small number of tests runs, but gives a valuable result from an engineering perspective in terms of a transfer function. The DoE prediction results, however, are only valid in the tested area. So a careful selection of input

  6. Cancer risks among iron and steel workers in Anshan, China, Part II: Case-control studies of lung and stomach cancer.

    PubMed

    Xu, Z; Brown, L M; Pan, G W; Liu, T F; Gao, G S; Stone, B J; Cao, R M; Guan, D X; Sheng, J H; Yan, Z S; Dosemeci, M; Fraumeni, J F; Blot, W J

    1996-07-01

    Nested case-control interview studies of lung cancer (610 incident cases), stomach cancer (292 incident cases), and 959 controls were conducted to follow up leads from a proportional mortality analysis of deaths among male workers in a large integrated iron-steel complex in Anshan, China. For lung cancer, after adjusting for the significant non-occupational risk factors (smoking, other pulmonary disease, family history of lung cancer, and low consumption of fruit or tea), risks were significantly elevated for those employed for 15 or more years in smelting and rolling (OR = 1.5, CI = 1.1-2.2), in the fire-resistant brick factory (OR = 2.9, CI = 1.4-5.9), in general loading (OR = 2.5, CI = 1.0-6.1), and as coke oven workers (OR = 3.4; CI = 1.4-8.5). For stomach cancer, after adjusting for consumption of pickled vegetables, prior gastric diseases, family history of stomach cancer, low intake of fruits and vegetables, and education, risks were significantly elevated for those employed for 15 or more years in ore sintering and transportation (OR = 2.1, CI = 1.0-4.4), in the fire-resistant brick factory (OR = 2.5, CI = 1.1-5.8), in general loading (OR = 3.2, CI = 1.2-8.9), as boilerworkers and cooks (OR = 2.6, CI = 1.2-5.6), and as coke oven workers (OR = 5.4, CI = 1.8-16.0). For both lung and stomach cancers, significant dose-response gradients were observed for exposure to total dust and benzo(a)pyrene, but not for specific chemical components of dust. Overall, long-term steel workers with exposure to workplace pollutants had a 40% increased risk of both lung and stomach cancers. These case-control studies confirm many of the occupational findings reported in the proportionate mortality analysis, and suggest avenues for further work to evaluate the carcinogenicity of individual components of dust.

  7. The Loss of China: A Selected Bibliography

    ERIC Educational Resources Information Center

    Hettig, David; Pozzetta, George E.

    1974-01-01

    This bibliographic review of books discussing the events involved in the loss of China to communism in the five years after World War II identifies basic resources on China, works mostly from the American point of view owing to the lack of availability of objective Chinese Scholarship. (JH)

  8. Synthesis and magnetic properties of a new family of macrocyclic M(II)3Ln(III) complexes: insights into the effect of subtle chemical modification on single-molecule magnet behavior.

    PubMed

    Feltham, Humphrey L C; Clérac, Rodolphe; Ungur, Liviu; Vieru, Veacheslav; Chibotaru, Liviu F; Powell, Annie K; Brooker, Sally

    2012-10-15

    Thirteen tetranuclear mixed-metal complexes of the hexaimine macrocycle (L(Pr))(6-) have been prepared in a one-pot 3:1:3:3 reaction of copper(II) acetate hydrate, the appropriate lanthanide(III) nitrate hydrate, 1,4-diformyl-2,3-dihydroxybenzene (1), and 1,3-diaminopropane. The resulting family of copper(II)-lanthanide(III) macrocyclic complexes has the general formula Cu(II)(3)Ln(III)(L(Pr))(NO(3))(3)·solvents (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Tb, Ho, Er, Tm, or Yb). X-ray crystal structure determinations carried out on [Cu(3)Ce(L(Pr))(NO(3))(3)(MeOH)(3)] and [Cu(3)Dy(L(Pr))(NO(3))(3)(MeOH)(3)] confirmed that the large Ln(III) ion is bound in the central O(6) site and the three square pyramidal Cu(II) ions in the outer N(2)O(2) sites (apical donor either nitrate anion or methanol molecule) of the Schiff base macrocycle. Only the structurally characterized Cu(3)Tb complex, reported earlier, is a single-molecule magnet (SMM): the other 12 complexes do not exhibit an out-of-phase ac susceptibility signal or hysteresis of magnetization in a dc field. Ab initio calculations allowed us to rationalize the observed magnetic properties, including the significant impact of subtle chemical modification on SMM behavior. Broken-symmetry density functional theory (BS-DFT) calculations show there is a subtle structural balance as to whether the Cu···Cu exchange coupling is ferro- or antiferromagnetic. Of the family of 13 magnetically characterized tetranuclear Cu(II)(3)Ln(III) macrocyclic complexes prepared, only the Tb(III) complex is an SMM: the theoretical reasons for this are discussed.

  9. 7 CFR 319.56-39 - Fragrant pears from China.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Fragrant pears from China. 319.56-39 Section 319.56-39.... (ii) Upon detection of peach fruit borer (Carposina sasaki), yellow peach moth (Conogethes.... (5) After harvest, the NPPO of China or officials authorized by the NPPO of China must inspect...

  10. Forecasting and prevention of water inrush during the excavation process of a diversion tunnel at the Jinping II Hydropower Station, China.

    PubMed

    Hou, Tian-Xing; Yang, Xing-Guo; Xing, Hui-Ge; Huang, Kang-Xin; Zhou, Jia-Wen

    2016-01-01

    Estimating groundwater inflow into a tunnel before and during the excavation process is an important task to ensure the safety and schedule during the underground construction process. Here we report a case of the forecasting and prevention of water inrush at the Jinping II Hydropower Station diversion tunnel groups during the excavation process. The diversion tunnel groups are located in mountains and valleys, and with high water pressure head. Three forecasting methods are used to predict the total water inflow of the #2 diversion tunnel. Furthermore, based on the accurate estimation of the water inrush around the tunnel working area, a theoretical method is presented to forecast the water inflow at the working area during the excavation process. The simulated results show that the total water flow is 1586.9, 1309.4 and 2070.2 m(3)/h using the Qshima method, Kostyakov method and Ochiai method, respectively. The Qshima method is the best one because it most closely matches the monitoring result. According to the huge water inflow into the #2 diversion tunnel, reasonable drainage measures are arranged to prevent the potential disaster of water inrush. The groundwater pressure head can be determined using the water flow velocity from the advancing holes; then, the groundwater pressure head can be used to predict the possible water inflow. The simulated results show that the groundwater pressure head and water inflow re stable and relatively small around the region of the intact rock mass, but there is a sudden change around the fault region with a large water inflow and groundwater pressure head. Different countermeasures are adopted to prevent water inrush disasters during the tunnel excavation process. Reasonable forecasting the characteristic parameters of water inrush is very useful for the formation of prevention and mitigation schemes during the tunnel excavation process.

  11. Spectroscopic characterization of active-site variants of the PduO-type ATP:corrinoid adenosyltransferase from Lactobacillus reuteri: insights into the mechanism of four-coordinate Co(II)corrinoid formation.

    PubMed

    Park, Kiyoung; Mera, Paola E; Escalante-Semerena, Jorge C; Brunold, Thomas C

    2012-04-16

    The PduO-type adenosine 5'-triphosphate (ATP):corrinoid adenosyltransferase from Lactobacillus reuteri (LrPduO) catalyzes the transfer of the adenosyl-group of ATP to Co(1+)cobalamin (Cbl) and Co(1+)cobinamide (Cbi) substrates to synthesize adenosylcobalamin (AdoCbl) and adenosylcobinamide (AdoCbi(+)), respectively. Previous studies revealed that to overcome the thermodynamically challenging Co(2+) → Co(1+) reduction, the enzyme drastically weakens the axial ligand-Co(2+) bond so as to generate effectively four-coordinate (4c) Co(2+)corrinoid species. To explore how LrPduO generates these unusual 4c species, we have used magnetic circular dichroism (MCD) and electron paramagnetic resonance (EPR) spectroscopic techniques. The effects of active-site amino acid substitutions on the relative yield of formation of 4c Co(2+)corrinoid species were examined by performing eight single-amino acid substitutions at seven residues that are involved in ATP-binding, an intersubunit salt bridge, and the hydrophobic region surrounding the bound corrin ring. A quantitative analysis of our MCD and EPR spectra indicates that the entire hydrophobic pocket below the corrin ring, and not just residue F112, is critical for the removal of the axial ligand from the cobalt center of the Co(2+)corrinoids. Our data also show that a higher level of coordination among several LrPduO amino acid residues is required to exclude the dimethylbenzimidazole moiety of Co(II)Cbl from the active site than to remove the water molecule from Co(II)Cbi(+). Thus, the hydrophilic interactions around and above the corrin ring are more critical to form 4c Co(II)Cbl than 4c Co(II)Cbi(+). Finally, when ATP analogues were used as cosubstrate, only "unactivated" five-coordinate (5c) Co(II)Cbl was observed, disclosing an unexpectedly large role of the ATP-induced active-site conformational changes with respect to the formation of 4c Co(II)Cbl. Collectively, our results indicate that the level of control exerted by

  12. Novel insights into mitotic chromosome condensation

    PubMed Central

    Piskadlo, Ewa; Oliveira, Raquel A.

    2016-01-01

    The fidelity of mitosis is essential for life, and successful completion of this process relies on drastic changes in chromosome organization at the onset of nuclear division. The mechanisms that govern chromosome compaction at every cell division cycle are still far from full comprehension, yet recent studies provide novel insights into this problem, challenging classical views on mitotic chromosome assembly. Here, we briefly introduce various models for chromosome assembly and known factors involved in the condensation process (e.g. condensin complexes and topoisomerase II). We will then focus on a few selected studies that have recently brought novel insights into the mysterious way chromosomes are condensed during nuclear division. PMID:27508072

  13. Sleep inspires insight.

    PubMed

    Wagner, Ullrich; Gais, Steffen; Haider, Hilde; Verleger, Rolf; Born, Jan

    2004-01-22

    Insight denotes a mental restructuring that leads to a sudden gain of explicit knowledge allowing qualitatively changed behaviour. Anecdotal reports on scientific discovery suggest that pivotal insights can be gained through sleep. Sleep consolidates recent memories and, concomitantly, could allow insight by changing their representational structure. Here we show a facilitating role of sleep in a process of insight. Subjects performed a cognitive task requiring the learning of stimulus-response sequences, in which they improved gradually by increasing response speed across task blocks. However, they could also improve abruptly after gaining insight into a hidden abstract rule underlying all sequences. Initial training establishing a task representation was followed by 8 h of nocturnal sleep, nocturnal wakefulness, or daytime wakefulness. At subsequent retesting, more than twice as many subjects gained insight into the hidden rule after sleep as after wakefulness, regardless of time of day. Sleep did not enhance insight in the absence of initial training. A characteristic antecedent of sleep-related insight was revealed in a slowing of reaction times across sleep. We conclude that sleep, by restructuring new memory representations, facilitates extraction of explicit knowledge and insightful behaviour.

  14. Mechanistic insights into a novel chromone-appended Cu(II) anticancer drug entity: in vitro binding profile with DNA/RNA substrates and cytotoxic activity against MCF-7 and HepG2 cancer cells.

    PubMed

    Yousuf, Imtiyaz; Arjmand, Farukh; Tabassum, Sartaj; Toupet, Loic; Khan, Rais Ahmad; Siddiqui, Maqsood Ahmad

    2015-06-14

    A new chromone-appended Cu(ii) drug entity () was designed and synthesized as a potential anticancer chemotherapeutic agent. The structural elucidation was carried out thoroughly by elemental analysis, FT-IR, EPR, ESI-MS and single crystal X-ray crystallography. Complex resulted from the in situ methoxylation reaction of the 3-formylchromone ligand and its subsequent complexation with the copper nitrate salt in a 2 : 1 ratio, respectively. crystallized in the monoclinic P21/c space group possessing the lattice parameters, a = 8.75 Å, b = 5.07 Å, c = 26.22 Å, α = γ = 90°, β = 96.3° per unit cell. Furthermore, in vitro interaction studies of with ct-DNA and tRNA were carried out which suggested more avid binding propensity towards the RNA target via intercalative mode, which was reflected from its Kb, K and Ksv values. The gel electrophoretic mobility assay was carried out on the pBR322 plasmid DNA substrate, to ascertain the cleaving ability and the mechanistic pathway in the presence of additives, and the results revealed the efficient cleaving ability of via the oxidative pathway. In vitro cell growth inhibition via the MTT assay was carried out to evaluate the cytotoxicity of complex and IC50 values were found to be in the range of 5-10 μg mL(-1) in HepG2 and MCF-7 cancer cell lines, which were found to be much lower than the IC50 values of previously reported similar Cu(ii) complexes. Additionally, in the presence of , reactive oxygen species (ROS) and thiobarbituric acid reactive substance (TBARS) levels in the tested cancer cell lines increased significantly, coupled with reduced glutathione (GSH) levels. Thus, our results suggested that ROS plays an important role in cell apoptosis induced by the Cu(ii) complex and validates its potential to act as a robust anticancer drug entity.

  15. First insight into the somatic mutation burden of neurofibromatosis type 2-associated grade I and grade II meningiomas: a case report comprehensive genomic study of two cranial meningiomas with vastly different clinical presentation.

    PubMed

    Dewan, Ramita; Pemov, Alexander; Dutra, Amalia S; Pak, Evgenia D; Edwards, Nancy A; Ray-Chaudhury, Abhik; Hansen, Nancy F; Chandrasekharappa, Settara C; Mullikin, James C; Asthagiri, Ashok R; Heiss, John D; Stewart, Douglas R; Germanwala, Anand V

    2017-02-13

    Neurofibromatosis type 2 (NF2) is a rare autosomal dominant nervous system tumor predisposition disorder caused by constitutive inactivation of one of the two copies of NF2. Meningiomas affect about one half of NF2 patients, and are associated with a higher disease burden. Currently, the somatic mutation landscape in NF2-associated meningiomas remains largely unexamined. Here, we present an in-depth genomic study of benign and atypical meningiomas, both from a single NF2 patient. While the grade I tumor was asymptomatic, the grade II tumor exhibited an unusually high growth rate: expanding to 335 times its initial volume within one year. The genomes of both tumors were examined by whole-exome sequencing (WES) complemented with spectral karyotyping (SKY) and SNP-array copy-number analyses. To better understand the clonal composition of the atypical meningioma, the tumor was divided in four sections and each section was investigated independently. Both tumors had second copy inactivation of NF2, confirming the central role of the gene in meningioma formation. The genome of the benign tumor closely resembled that of a normal diploid cell and had only one other deleterious mutation (EPHB3). In contrast, the chromosomal architecture of the grade II tumor was highly re-arranged, yet uniform among all analyzed fragments, implying that this large and fast growing tumor was composed of relatively few clones. Besides multiple gains and losses, the grade II meningioma harbored numerous chromosomal translocations. WES analysis of the atypical tumor identified deleterious mutations in two genes: ADAMTSL3 and CAPN5 in all fragments, indicating that the mutations were present in the cell undergoing fast clonal expansion CONCLUSIONS: This is the first WES study of NF2-associated meningiomas. Besides second NF2 copy inactivation, we found low somatic burden in both tumors and high level of genomic instability in the atypical meningioma. Genomic instability resulting in altered gene

  16. Late Permian high-Mg andesite and basalt association from northern Liaoning, North China: Insights into the final closure of the Paleo-Asian ocean and the orogen-craton boundary

    NASA Astrophysics Data System (ADS)

    Yuan, Lingling; Zhang, Xiaohui; Xue, Fuhong; Lu, Yinghuai; Zong, Keqing

    2016-08-01

    High-Mg andesites (HMAs) and related basalts constitute a volumetrically minor, but genetically important occurrence along most convergent plate margins of various ages on Earth. The details of their petrogenesis can contain critical information for resolving essential geodynamic and crustal evolutionary issues. This zircon U-Pb dating and geochemical study documents the late Permian metamorphosed high-Mg basaltic to andesitic suite from Kaiyuan of northern Liaoning, North China. These rocks feature SiO2 contents ranging from 48.7 to 63.2 wt.%, high Mg# values of 63-75, an enrichment in large-ion lithophile elements (LILE), and depletion in high field strength elements (HFSE). They possess whole-rock initial 87Sr/86Sr ratios of 0.70417-0.70457, εNd(t) values from - 0.4 to 5.0, and εHf(t) values from 5.1 to 11, as well as zircon εHf(t) values from - 9.4 to 0.4. These features indicate that their petrogenesis most likely involved precursory metasomatism of mantle peridotites by melts from subduction-related sediments, and subsequent partial melting. With a depleted mantle source and possible tectonic link to post-subduction slab break-off, the Kaiyuan suite could present a spatial reference not only for defining the demarcation line between the North China craton (NCC) and the Central Asian Orogenic belt (CAOB) in the region, but also for tracing the final location of the cryptic suturing zone of the Paleo-Asian Ocean. Synthesizing the suite with coeval igneous episodes as well as concomitant metamorphic events along the Solonker-Xra Moron-Changchun zone leads to the characterization of the eventual closure of the Paleo-Asian Ocean within a double-sided subduction system during late Permian-Early Triassic.

  17. National Quality Assessment of Early Clopidogrel Therapy in Chinese Patients With Acute Myocardial Infarction (AMI) in 2006 and 2011: Insights From the China Patient-Centered Evaluative Assessment of Cardiac Events (PEACE)–Retrospective AMI Study

    PubMed Central

    Zhang, Lihua; Desai, Nihar R; Li, Jing; Hu, Shuang; Wang, Qing; Li, Xi; Masoudi, Frederick A; Spertus, John A; Nuti, Sudhakar V; Wang, Sisi; Krumholz, Harlan M; Jiang, Lixin

    2015-01-01

    Background Early clopidogrel administration to patients with acute myocardial infarction (AMI) has been demonstrated to improve outcomes in a large Chinese trial. However, patterns of use of clopidogrel for patients with AMI in China are unknown. Methods and Results From a nationally representative sample of AMI patients from 2006 and 2011, we identified 11 944 eligible patients for clopidogrel therapy and measured early clopidogrel use, defined as initiation within 24 hours of hospital admission. Among the patients eligible for clopidogrel, the weighted rate of early clopidogrel therapy increased from 45.7% in 2006 to 79.8% in 2011 (P<0.001). In 2006 and 2011, there was significant variation in early clopidogrel use by region, ranging from 1.5% to 58.0% in 2006 (P<0.001) and 48.7% to 87.7% in 2011 (P<0.001). While early use of clopidogrel was uniformly high in urban hospitals in 2011 (median 89.3%; interquartile range: 80.1% to 94.5%), there was marked heterogeneity among rural hospitals (median 50.0%; interquartile range: 11.5% to 84.4%). Patients without reperfusion therapy and those admitted to rural hospitals were less likely to be treated with clopidogrel. Conclusions Although the use of early clopidogrel therapy in patients with AMI has increased substantially in China, there is notable wide variation across hospitals, with much less adoption in rural hospitals. Quality improvement initiatives are needed to increase consistency of early clopidogrel use for patients with AMI. Clinical Trial Registration URL: https://www.clinicaltrials.gov/. Unique identifier: NCT01624883. PMID:26163041

  18. Computational insights on crystal structures of the oxygen-evolving complex of photosystem II with either Ca²⁺ or Ca²⁺ substituted by Sr²⁺

    DOE PAGES

    Vogt, Leslie; Ertem, Mehmed Z.; Pal, Rhitankar; ...

    2015-01-15

    The oxygen-evolving complex of photosystem II can function with either Ca²⁺ or Sr²⁺ as the heterocation, but the reason for differing turnover rates remains unresolved despite reported X-ray crystal structures for both forms. Using quantum mechanics/molecular mechanics (QM/MM) calculations, we optimize structures with each cation in both the resting state (S₁) and in a series of reduced states (S₀, S₋₁, and S-₂). Through comparison with experimental data, we determine that X-ray crystal structures with either Ca²⁺ or Sr²⁺ are most consistent with the S-₂ state, Mn₄[III,III,III,II] with O4 and O5 protonated. As expected, the QM/MM models show that Ca²⁺/Sr²⁺ substitutionmore » results in elongation of the heterocation bonds and displaces terminal waters W3 and W4. The optimized structures also show that hydrogen-bonded W5 is displaced in all S states with Sr²⁺ as the heterocation, suggesting that this water may play a critical role during water oxidation.« less

  19. Computational insights on crystal structures of the oxygen-evolving complex of photosystem II with either Ca²⁺ or Ca²⁺ substituted by Sr²⁺

    SciTech Connect

    Vogt, Leslie; Ertem, Mehmed Z.; Pal, Rhitankar; Brudvig, Gary W.; Batista, Victor S.

    2015-01-15

    The oxygen-evolving complex of photosystem II can function with either Ca²⁺ or Sr²⁺ as the heterocation, but the reason for differing turnover rates remains unresolved despite reported X-ray crystal structures for both forms. Using quantum mechanics/molecular mechanics (QM/MM) calculations, we optimize structures with each cation in both the resting state (S₁) and in a series of reduced states (S₀, S₋₁, and S-₂). Through comparison with experimental data, we determine that X-ray crystal structures with either Ca²⁺ or Sr²⁺ are most consistent with the S-₂ state, Mn₄[III,III,III,II] with O4 and O5 protonated. As expected, the QM/MM models show that Ca²⁺/Sr²⁺ substitution results in elongation of the heterocation bonds and displaces terminal waters W3 and W4. The optimized structures also show that hydrogen-bonded W5 is displaced in all S states with Sr²⁺ as the heterocation, suggesting that this water may play a critical role during water oxidation.

  20. Enhanced Analgesic Properties and Reduced Ulcerogenic Effect of a Mononuclear Copper(II) Complex with Fenoprofen in Comparison to the Parent Drug: Promising Insights in the Treatment of Chronic Inflammatory Diseases

    PubMed Central

    Gumilar, Fernanda; Boeris, Mónica; Toso, Ricardo; Minetti, Alejandra

    2014-01-01

    Analgesic and ulcerogenic properties have been studied for the copper(II) coordination complex of the nonsteroidal anti-inflammatory drug Fenoprofen and imidazole [Cu(fen)2(im)2] (Cu: copper(II) ion; fen: fenoprofenate anion from Fenoprofen, im: imidazole). A therapeutic dose of 28 mg/kg was tested for [Cu(fen)2(im)2] and 21 mg/kg was employed for Fenoprofen calcium, administered by oral gavage in female mice to compare the therapeutic properties of the new entity. The acetic acid induced writhing test was employed to study visceral pain. The percentage of inhibition in writhing and stretching was 78.9% and 46.2% for the [Cu(fen)2(im)2] and Fenoprofen calcium, respectively. This result indicates that the complex could be more effective in diminishing visceral pain. The formalin test was evaluated to study the impact of the drugs over nociceptive and inflammatory pain. The complex is a more potent analgesic on inflammatory pain than the parent drug. Ulcerogenic effects were evaluated using a model of gastric lesions induced by hypothermic-restraint stress. Fenoprofen calcium salt caused an ulcer index of about 79 mm2 while the one caused by [Cu(fen)2(im)2] was 22 mm2. The complex diminished the development of gastric mucosal ulcers in comparison to the uncomplexed drug. Possible mechanisms of action related to both therapeutic properties have been discussed. PMID:25050353

  1. Types of Insight.

    ERIC Educational Resources Information Center

    Stadler, Holly

    1984-01-01

    Presents a conceptual model of insight that is distinct from any theory or philosophy. Six types of insight are described: associative, aggregate, discrete process, ontogenetic process, phylogenetic process, and transcendent process. The model offers counselors a method for the enhancement of empathy and the development of client insight…

  2. Localisation of keratin K78 in the basal layer and first suprabasal layers of stratified epithelia completes expression catalogue of type II keratins and provides new insights into sequential keratin expression.

    PubMed

    Langbein, Lutz; Eckhart, Leopold; Fischer, Heinz; Rogers, Michael A; Praetzel-Wunder, Silke; Parry, David A D; Kittstein, Walter; Schweizer, Juergen

    2016-03-01

    Among the 26 human type II keratins, K78 is the only one that has not yet been explored with regard to its expression characteristics. Here, we show that, at both the transcriptional and translational levels, K78 is strongly expressed in the basal and parabasal cell layers with decreasing intensity in the lower suprabasal cells of keratinising and non-keratinising squamous epithelia and keratinocyte cultures. The same pattern has been detected at the transcriptional level in the corresponding mouse epithelia. Murine K78 protein, which contains an extraordinary large extension of its tail domain, which is unique among all known keratins, is not detectable by the antibody used. Concomitant studies in human epithelia have confirmed K78 co-expression with the classical basal keratins K5 and K14. Similarly, K78 co-expression with the differentiation-related type I keratins K10 (epidermis) and K13 (non-keratinising epithelia) occurs in the parabasal cell layer, whereas that of the corresponding type II keratins K1 (epidermis) and K4 (non-keratinising epithelia) unequivocally starts subsequent to the respective type I keratins. Our data concerning K78 expression modify the classical concept of keratin pair K5/K14 representing the basal compartment and keratin pairs K1/K10 or K4/K13 defining the differentiating compartment of stratified epithelia. Moreover, the K78 expression pattern and the decoupled K1/K10 and K4/K13 expression define the existence of a hitherto unperceived early differentiation stage in the parabasal layer characterized by K78/K10 or K78/K13 expression.

  3. Source insights into the 11-h daytime and nighttime fine ambient particulate matter in China as well as the synthetic studies using the new Multilinear Engine 2-species ratios (ME2-SR) method.

    PubMed

    Shi, Guoliang; Chen, Gang; Liu, Guirong; Wang, Haiting; Tian, Yingze; Feng, Yinchang

    2016-10-01

    Modeled results are very important for environmental management. Unreasonable modeled result can lead to wrong strategy for air pollution management. In this work, an improved physically constrained source apportionment (PCSA) technology known as Multilinear Engine 2-species ratios (ME2-SR) was developed to the 11-h daytime and nighttime fine ambient particulate matter in urban area. Firstly, synthetic studies were carried out to explore the effectiveness of ME2-SR. The estimated source contributions were compared with the true values. The results suggest that, compared with the positive matrix factorization (PMF) model, the ME2-SR method could obtain more physically reliable outcomes, indicating that ME2-SR was effective, especially when apportioning the datasets with no unknown source. Additionally, 11-h daytime and nighttime PM2.5 samples were collected from Tianjin in China. The sources of the 11-h daytime and nighttime fine ambient particulate matter in China were identified using the new method and the PMF model. The calculated source contributions for ME2-SR for daytime PM2.5 samples are resuspended dust (38.91 μg m(-3), 26.60%), sulfate and nitrate (38.60 μg m(-3), 26.39%), vehicle exhaust and road dust (38.26 μg m(-3), 26.16%) and coal combustion (20.14 μg m(-3), 13.77%), and those for nighttime PM2.5 samples are resuspended dust (18.78 μg m(-3), 12.91%), sulfate and nitrate (41.57 μg m(-3), 28.58%), vehicle exhaust and road dust (38.39 μg m(-3), 26.39%), and coal combustion (36.76 μg m(-3), 25.27%). The comparisons of the constrained versus unconstrained outcomes clearly suggest that the physical meaning of the ME2-SR results is interpretable and reliable, not only for the specified species values but also for source contributions. The findings indicate that the ME2-SR method can be a useful tool in source apportionment studies, for air pollution management. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Integrated in situ U-Pb Age and Hf-O Analyses of Zircon from the Northern Yangtze Block: New Insights into the Neoproterozoic Low-δ18O Magmas in the South China Block

    NASA Astrophysics Data System (ADS)

    Yang, Y. N.; Wang, X. C.; Li, Q. L.; Li, X. H.

    2015-12-01

    The oxygen isotopic composition of Neoproterozoic magmas from the northern Yangtze Block holds a key for the origin of large-scale 18O depletion in the HP and UHP metamorphic rocks in the Dabie-Sulu orogenic belt, northern margin of the South China Block. We report here the integrated in situ U-Pb dating and O-Hf isotope analyses of zircon grains from sedimentary and volcanic rocks of the late Neoproterozoic Suixian Group (SG) from the northern Yangtze Block. Detrital zircon grains display age peaks of 0.73-0.74 Ga, 0.79 Ga, and 2.0 Ga. Zircon U-Pb ages together with Hf-O isotopic composition indicate provenance of SG dominantly from proximal Neoproterozoic igneous rock and likely hidden Paleoproterozoic basement along the northern margin of the Yangtze Block. The zircon δ18O values from SG range from 10.5‰ to 1.3‰. Zircon grains with negative δ18O value, typical result of magma-ice interaction, were not identified in this study. The major phase of low-δ18O (< 4‰) magmas initiated at ca. 780 Ma, long before the first glaciation event (< 715 Ma) in the South China Block. Thus caution should be taken when using low-δ18O zircon grains to infer cold climate. Low-δ18O zircon grains have large ranges of ɛHf(t) values, varying from -15.5 to 10.7, concentrating on negative ɛHf(t). This strongly argues against the possibility that the low-δ18O magma was produced by partial melting of high-temperature hydrothermally altered oceanic crust because this model predicted MORB-like Hf isotopes for the resultant low-δ18O magmas. This study emphasizes that high-T water-rock interaction and continental rifting tectonic setting are essential to generate abundant low-δ18O magmas. The important application of our study is to confirm that most of negative-δ18O zircons identified in HP and UHP metamorphic rocks may not have been inherited from their Neoproterozoic protoliths.

  5. Photobilirubin II.

    PubMed Central

    Bonnett, R; Buckley, D G; Hamzetash, D; Hawkes, G E; Ioannou, S; Stoll, M S

    1984-01-01

    An improved preparation of photobilirubin II in ammoniacal methanol is described. Evidence is presented which distinguishes between the two structures proposed earlier for photobilirubin II in favour of the cycloheptadienyl structure. Nuclear-Overhauser-enhancement measurements with bilirubin IX alpha and photobilirubin II in dimethyl sulphoxide are complicated by the occurrence of negative and zero effects. The partition coefficient of photobilirubin II between chloroform and phosphate buffer (pH 7.4) is 0.67. PMID:6743241

  6. SAGE II

    Atmospheric Science Data Center

    2016-02-16

    SAGE II Data and Information The goals of the Stratospheric Aerosol and Gas Experiment ( SAGE ) II are to determine the spatial distributions of stratospheric ... profiles and calculating monthly averages of each. The SAGE II sensor (a Sun Photometer) was launched into a 57-degree inclination ...

  7. Short- and long-term earthquake triggering along the strike-slip Kunlun fault, China: Insights gained from the Ms 8.1 Kunlun earthquake and other modern large earthquakes

    NASA Astrophysics Data System (ADS)

    Xie, Chaodi; Lei, Xinglin; Wu, Xiaoping; Hu, Xionglin

    2014-03-01

    Following the 2001 Ms8.1 Kunlun earthquake, earthquake records of more than 10 years, in addition to more than one century's records of large earthquakes, provide us with a chance to examine short-term (days to a few years) and long-term (years to decades) seismic triggering following a magnitude ~ 8 continental earthquake along a very long strike-slip fault, the Kunlun fault system, located in northern Tibet, China. Based on the calculations of coseismic Coulomb stress changes (ΔCFS) from the larger earthquake and post-seismic stress changes due to viscoelastic stress relaxation in the lower crust and upper mantle, we examined the temporal evolution of seismic triggering. The ETAS (epidemic type aftershocks sequence) model shows that the seismic rate in the aftershock area over ~ 10 years was higher than the background seismicity before the mainshock. Moreover, we discuss long-term (years to decades) triggering and the evolution of stress changes for the sequence of five large earthquakes of M ≥ 7.0 that ruptured the Kunlun fault system since 1937. All subsequent events of M ≥ 7.0 occurred in the regions of positive accumulated ΔCFS. These results show that short-term (up to 200 days in our case) triggering along the strike-slip Kunlun fault is governed by coseismic stress changes, while long-term triggering is somewhat due to post-seismic Coulomb stress changes resulting from viscoelastic relaxation.

  8. A novel missense mutation in the HSD3B2 gene, underlying nonsalt-wasting congenital adrenal hyperplasia. new insight into the structure-function relationships of 3β-hydroxysteroid dehidrogenase type II.

    PubMed

    Baquedano, María Sonia; Ciaccio, Marta; Marino, Roxana; Perez Garrido, Natalia; Ramirez, Pablo; Maceiras, Mercedes; Turjanski, Adrian; Defelipe, Lucas A; Rivarola, Marco A; Belgorosky, Alicia

    2015-01-01

    3βHSD2 is a bifunctional microsomal NAD+-dependent enzyme crucial for adrenal and gonad steroid biosynthesis, converting Δ5-steroids to Δ4-steroids. 3βHSD2 deficiency is a rare cause of congenital adrenal hyperplasia caused by recessive loss-of-function HSD3B2 mutations. The aim was to define the pathogenic consequences of a novel missense mutation in the HSD3B2 gene. We report a 7-month-old 46,XX girl referred because of precocious pubarche and postnatal clitoromegaly. Hormonal profile showed inadequate glucocorticoid levels, increased 17OHP and renin levels, and very high DHEAS levels, suggestive of compensated nonsalt-losing 3βHSD2 deficiency. Direct sequencing revealed a novel, homozygous, pG250V HSD3B2 mutation. In vitro analysis in intact COS-7 cells showed impaired enzymatic activity for the conversion of pregnenolone to progesterone and dehydroepiandrosterone to androstenedione (20% and 27% of WT at 6 h, respectively). G250V-3βHSD2 decreased the Vmax for progesterone synthesis without affecting the Km for pregnenolone. Western blot and immunofluorescence suggested that p.G250V mutation has no effect on the expression and intracellular localization of the mutant protein. Molecular homology modeling predicted that mutant V250 affected an L239-Q251 loop next to a β-sheet structure in the NAD+-binding domain. We identified a novel p.G250V mutation of HSD3B2 which causes an incomplete loss of enzymatic activity, explaining the compensated nonsalt loss phenotype. In vitro and in silico experiments provided insight into the structure-function relationship of the 3βHSD2 protein suggesting the importance of the L239-Q251 loop for the catalytic activity of the otherwise stable 3βHSD2 enzyme.

  9. China Dust

    Atmospheric Science Data Center

    2013-04-16

    ... SpectroRadiometer (MISR) nadir-camera images of eastern China compare a somewhat hazy summer view from July 9, 2000 (left) with a ... arid and sparsely vegetated surfaces of Mongolia and western China pick up large quantities of yellow dust. Airborne dust clouds from the ...

  10. Insights into the need for permanent pacemaker following implantation of the repositionable LOTUS valve for transcatheter aortic valve replacement in 250 patients: results from the REPRISE II trial with extended cohort.

    PubMed

    Dumonteil, Nicolas; Meredith, Ian T; Blackman, Daniel J; Tchétché, Didier; Hildick-Smith, David; Spence, Mark S; Walters, Darren L; Harnek, Jan; Worthley, Stephen G; Rioufol, Gilles; Lefèvre, Thierry; Modine, Thomas; Van Mieghem, Nicolas; Houle, Vicki M; Allocco, Dominic J; Dawkins, Keith D

    2017-09-20

    This analysis aimed to evaluate the incidence and predictors of the need for permanent pacemaker (PPM) implantation following implantation of the repositionable and fully retrievable LOTUS Aortic Valve Replacement System. The prospective, single-arm, multicentre REPRISE II study with extended cohort enrolled 250 symptomatic, high surgical risk patients with severe aortic stenosis for transfemoral transcatheter aortic valve implantation (TAVI) with a 23 mm or 27 mm LOTUS valve. Echocardiography, computed tomography, and electrocardiography data were evaluated by independent core labs. Post TAVI, 32.0% (72/225) of pacemaker-naïve patients underwent new PPM implantation at 30 days. Most (59/72, 82%) patients were implanted for third-degree atrioventricular block, and >10% overstretch of the LVOT by area was observed in 59.7% (43/72) of PPM patients. Significant independent predictors of PPM at 30 days included baseline RBBB (odds ratio [OR] 12.7, 95% CI: 4.5, 36.2; p<0.001) and LVOT overstretch >10% (OR 3.4, 95% CI: 1.7, 6.7; p<0.001). There was a trend towards a lower 30-day PPM rate in patients with a shallower (≤5 mm) implant depth (23.9% ≤5 mm vs. 36.9% >5 mm depth from LCS; p=0.06). Careful attention to valve sizing and implant depth may help to reduce the rate of PPM with the LOTUS valve.

  11. Evaluating the Timing of Volcanism at Baitoushan Volcano (North Korea/China) in the Context of Open-system Effects: Insights from Sr, Nd, and Pb Isotopes at the Single Grain Scale

    NASA Astrophysics Data System (ADS)

    Ramos, F. C.; Gill, J. B.; Rodgers, S. L.

    2007-12-01

    Baitoushan volcano, located along the North Korean-China border, is responsible for one of the largest caldera- forming rhyolitic eruptions in the northern hemisphere in the last 2000 years. In addition to an ~1000AD eruption, additional activity occurred at ~0AD and ~2000BC. These eruptions ejected large volumes of comenditic airfall and pyroclastic materials in addition to a small pantelleritic airfall deposit. We are at the initial stage of evaluating the sources of isotope variations, including whether these systems are open or closed, in order to evaluate the timing and residence of highly alkaline rhyolitic magma systems. Initial whole-rock isotope ratios suggest that young (<10ka) Baitoushan satellite basalts generally have slightly lower 87Sr/86Sr and higher 143Nd/144Nd than similarly young comendites, while the pantellerite has 143Nd/144Nd ratios similar to basalts. Sr isotopes in basalt hosted plagioclase crystals are generally higher than both whole rock hosts and accompanying clinopyroxene crystals, suggesting isotopic modification of basalts at crustal depths. These plagioclase 87Sr/86Sr ratios are similar to those in comendites and are consistent with early crustal inputs of either a limited amount of regional Archean basement or more extensive assimilation of Baitoushan "root" rocks with similar isotopic ratios. If limited, elevated Rb/Sr ratios in these rocks and resulting 87Sr/86Sr ratios in the comendites should be able to date magmatic residence while Nd and Pb isotopes remain constant. Such evaluations will be undertaken at the single grain scale where any potential of "open-ness" of the system can be constrained. Results will aid in determining the extent to which chronometric information is degraded by open-system processes leading up to large volume rhyolite eruptions.

  12. New insights into the lowest Xuanwei Formation in eastern Yunnan Province, SW China: Implications for Emeishan large igneous province felsic tuff deposition and the cause of the end-Guadalupian mass extinction

    NASA Astrophysics Data System (ADS)

    Zhao, Lixin; Dai, Shifeng; Graham, Ian T.; Li, Xiao; Zhang, Beibei

    2016-11-01

    A previous study suggested that the lowest Xuanwei Formation is derived from weathered clastic materials of silicic composition from the Emeishan large igneous province (ELIP) based on chemostratigraphic correlations (Al2O3/TiO2 ratios) between the two. In this study, we have adopted the model that the Emeishan mantle plume commenced and terminated within a short duration and have investigated the detailed mineralogy and geochemistry of carefully sampled rocks from the lower sections of the Xuanwei Formation, eastern Yunnan Province, Southwest China. These samples are intensely argillized and characterized by high proportions of clay minerals and quartz. The samples with Al2O3/TiO2 > 7 from the lowest Xuanwei Formation have an anomalous natural gamma response and high concentrations of Nb, Ta, Zr, Hf, Th, U, Ga and REY (rare earth elements and yttrium). Our results suggest that the samples with Al2O3/TiO2 > 7 from the lowest Xuanwei Formation represent felsic volcanic tuff instead of acidic clasts as originally proposed. The lowest Xuanwei Formation and the Wangpo Bed are the felsic tuffaceous layers interbedded with clastic rocks derived from the Emeishan high-Ti basalts. Such volcanic layers most likely represent ELIP felsic tuff originated from the extrusive equivalent of Nb-Zr-enriched alkaline syenitic magmatism at the waning stage of Emeishan mantle plume activity. This study has verified the existence of extensive alkaline felsic volcanism of early Late Permian age. Such alkaline volcanism may have been catastrophic and have contributed to the end-Guadalupian mass extinction.

  13. In situ major and trace element analysis of amphiboles in quartz monzodiorite porphyry from the Tonglvshan Cu-Fe (Au) deposit, Hubei Province, China: insights into magma evolution and related mineralization

    NASA Astrophysics Data System (ADS)

    Duan, Deng-Fei; Jiang, Shao-Yong

    2017-05-01

    The Tonglvshan deposit is the largest Cu-Fe (Au) skarn deposit in the Edong district, which is located in the westernmost part of the Middle and Lower Yangtze River metallogenic belt, China. In this study, we performed a detailed in situ analysis of major and trace elements in amphiboles from the ore-related Tonglvshan quartz monzodiorite porphyry using electron microprobe (EMPA) analysis and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Two distinct populations of amphiboles, which can be distinguished by their aluminum content, are found in the quartz monzodiorite porphyry. The low-aluminum (Low-Al) amphiboles are subhedral or anhedral and formed at 46.3-73.5 MPa and 713-763 °C. In contrast, the high-aluminum (High-Al) amphiboles are euhedral and formed at 88-165 MPa and 778-854 °C. Some euhedral amphiboles are partially or completely replaced by Low-Al amphibole. The compositions of parental melts in equilibrium with the High-Al amphibole ( Melt 1) and Low-Al amphibole ( Melt 2) were computed by applying solid/liquid partition coefficients. This modeling shows that magma in equilibrium with High-Al amphibole ( Melt 1) underwent 40% fractional crystallization of amphibole, plagioclase and apatite at a depth of 5 km to evolve to magma in equilibrium with Low-Al amphibole ( Melt 2). Copper enrichment occurred in the magma after undergoing fractional crystallization. The magma had a high oxygen fugacity, increasing from NNO + 1 ( Melt 1) through NNO + 2 to HM ( Melt 2), which could have prevented the loss of Cu (and possibly Au) to sulfide minerals during crystallization. Finally, the evolved magma intruded to shallower depths, where it presumably exsolved aqueous ore-forming fluids. Therefore, the large Cu-Fe-Au reserves of the Tonglvshan deposit can likely be attributed to a combination of controlling factors, including high oxygen fugacity, fractional crystallization, fluid exsolution, and a shallow emplacement depth.

  14. Structure-function relationships in the 47-kDa antenna protein and its complex with the photosystem II reaction center core: insights from picosecond fluorescence decay kinetics and resonance Raman spectroscopy.

    PubMed

    de Paula, J C; Liefshitz, A; Hinsley, S; Lin, W; Chopra, V; Long, K; Williams, S A; Belts, S; Yocum, C F

    1994-02-15

    We report the fluorescence decay kinetics and the vibrational properties of chlorophyll a bound to the 47-kDa antenna protein (CP47) of spinach photosystem II. The chlorophyll fluorescence of CP47 samples decays with four lifetimes (tau = 75.8 ps, 1.05 ns, 3.22 ns, and 5.41 ns). The 75.8-ps and 3.22-ns components are associated with chlorophyll a bound to relatively intact centers, the 1.05-ns component corresponds to chlorophyll bound to centers that are slightly perturbed, and the the 5.41-ns phase probably originates from centers that are severely denatured. The resonance Raman spectrum of CP47 at 441.6 nm (this work) and at 406.7 nm [de Paula, J. C., Ghanotakis, D. F., Bowlby, N. R., Dekker, J. P., Yocum, C. F., & Babcock, G. T. (1990) in Current Research in Photosynthesis (Baltscheffsky, M., Ed.), Vol. I, pp 643-646, Kluwer Academic Publishers, Dordrecht, The Netherlands] shows heterogeneity in the C = O stretching region. This part of the spectrum monitors the environment of the keto group at position 9 of the chlorophyll a molecule. We show that several structurally distinct pools of chlorophyll a are bound to CP47. Four of these may be distinguished by their C9 = O stretching frequencies (nu C = O = 1670, 1688, 1693, and 1701 cm-1). By analyzing the resonance enhancement pattern of these modes, we ascribe the 1693-cm-1 vibration to denatured centers. Of the remaining populations, we propose that the 1670-cm-1 vibration is consistent with a hydrogen bond between the C9 = O group of chlorophyll a and the protein. We elaborate on the role of this chromophore-protein interaction in the mechanism of energy transfer within the 47-kDa antenna protein.

  15. Palladium(II) chloride complexation: Spectrophotometric investigation in aqueous solutions from 5 to 125°C and theoretical insight into Pd-Cl and Pd-OH2 interactions

    SciTech Connect

    Boily, Jean F.; Seward, Terry M.

    2005-08-01

    The thermodynamic stabilities of these complexes were studied in aqueous solutions from 5 to 125°C with UV-vis spectrophotometry using a quartz flow-through cell. Tentative measurements up to 200°C were also carried out in pressurised titanium and gold-lined optical cells but revealed important losses in soluble palladium. The strong ligand-to-metal charge transfer bands of the palladium complexes below 350 nm were used to constrain the stepwise thermodynamic formation constants at each temperature, using results of singular value decompositions of the spectra over a broad range of palladium:chloride ratios and wavelengths. The temperature-dependent constants were used to obtain changes in enthalpy and in entropy for each reaction. The thermodynamic stabilities of PdCl(H2O)3+, PdCl2(H2O)20, and PdCl3(H2O)- are larger at higher temperatures, whilst the one of PdCl42- is smaller. All changes in entropies are positive for the former three species, but negative for the latter, presumably due to a larger solvent reorganisation around the doubly charged PdCl42- species. The room temperature thermodynamic values derived from this study are also in agreement with previously published calorimetric data. Theoretical calculations on the intramolecular distributions of electrons in the different palladium(II) chloro aqua complexes, using the methods of atoms in molecules and of the electron localisation function, showed Pd-Cl and Pd-OH2 interactions to be of largely closed-shell/ionic nature. These interactions induce an important distortion of the outer core shell electrons of Pd, as well as stable accumulations of electrons between adjacent Pd-Cl and Pd-OH2 bonds known as ligand opposed core charge concentrations

  16. [Characteristics and adaption of seasonal drought in southern China under the background of global climate change. II. Spatiotemporal characteristics of drought for wintering grain- and oil crops based on crop water deficit index].

    PubMed

    Sui, Yue; Huang, Wan-Hua; Yang, Xiao-Guang; Li, Mao-Song

    2012-09-01

    In recent years, seasonal drought occurs frequently in southern China, giving severe impact on the production of local wintering crops. Based on the 1959-2009 meteorological data from 268 meteorological stations in southern China, and by using crop water deficit index (CWDI) as agricultural drought index, this paper analyzed the spatiotemporal characteristics of drought for winter wheat and rapeseed. The results showed that in southern China, drought happened more frequently in Southwest China, north Huaihe basin, and parts of South China during the developmental stages of wintering crops. In the mid-lower Yangtze basin, the intensity and extent of drought increased during the mid-late developmental stages of winter wheat, and became much heavier at its later developmental stages. For rapeseed, the intensity and extent of drought increased during the developmental stage before winter and the late developmental stages. In southwest part, the intensity and extent of drought increased significantly during the developmental stage before winter for winter wheat and rapeseed. Since the early 1990s, the intensity and extent of drought in southern China increased during the mid-late developmental stages of wintering crops.

  17. There Are Only Four Dogs in China

    ERIC Educational Resources Information Center

    Selman, Gordon R.

    1974-01-01

    Reflecting on a visit to China, the article offers some insights into the workings and values of Chinese society and a glimpse of the part adult education plays in the process. Ideological education is a primary concern and technical and vocational training are emphasized. Politics is clearly in command. (MW)

  18. Financing Higher Education: Lessons from China

    ERIC Educational Resources Information Center

    Fengliang, Li

    2012-01-01

    In China, debates about higher education finance led to the introduction of a cost-sharing model, whereby students were required to pay tuition fees, over a decade ago. However, there is still significant resistance towards such a system within the broader society. In order to share insights into the development of the cost-sharing policy in China…

  19. Financing Higher Education: Lessons from China

    ERIC Educational Resources Information Center

    Fengliang, Li

    2012-01-01

    In China, debates about higher education finance led to the introduction of a cost-sharing model, whereby students were required to pay tuition fees, over a decade ago. However, there is still significant resistance towards such a system within the broader society. In order to share insights into the development of the cost-sharing policy in China…

  20. Mo-mineralized porphyries are relatively hydrous and differentiated: insights from the Permian-Triassic granitic complex in the Baituyingzi Mo-Cu district, eastern Inner Mongolia, NE China

    NASA Astrophysics Data System (ADS)

    Sun, Yan; Liu, Jianming; Zeng, Qingdong; Wang, Jingbin; Wang, Yuwang; Hu, Ruizhong; Zhou, Lingli; Wu, Guanbin

    2016-12-01

    Mo-Cu mineralization in the Baituyingzi district of eastern Inner Mongolia occurs within a granitic complex. This paper presents and discusses zircon U-Pb ages and whole-rock geochemical and Sr-Nd-Pb isotopic data from the granitic complex as potential indicators for porphyry Mo fertility. The U-Pb ages indicate that five units of the granitic complex were emplaced between 265.2 ± 0.7 and 246.5 ± 1.0 Ma. Constrained by crosscutting dikes, Mo-Cu mineralization was probably related to the Baituyingzi monzogranite porphyry dated at 248.2 ± 0.64 Ma. The intrusions belong to high-K calc-alkaline to shoshonitic series that are characterized by highly fractionated rare earth element (REE) patterns and strong enrichments of large ion lithophile elements, relative to high-field strength elements. Apart from the ˜246-Ma dike that shows negative ɛNd (t) values (-14.9 to -13.1), the intrusions have ɛNd(t) values ranging from -3.9 to 1.0, relatively young depleted mantle model ages (811 to 1183 Ma), 206Pb/204Pb of 18.137-18.335, and 207Pb/204Pb of 15.591-15.625, which are consistent with a juvenile lower crustal origin. Among the intrusions, the ˜248-Ma porphyry and the ˜246-Ma dike show adakite-like characteristics (e.g., Sr/Y = 44.9-185) and listric-shaped REE patterns that indicate amphibole fractionation and a hydrous magma source. However, the porphyry exhibits a higher differentiation index (81.4-91.5) and a steeper REE profile (e.g., LaN/YbN = 25.6-87.0) than those of the ˜246-Ma dike, which suggests that it is highly differentiated. We propose that the complex was generated by the partial melting of juvenile mafic lower crust (containing minor old crustal relicts) that was triggered by collision between the North China Craton and Siberian Craton. As indicated by the Th/Nb, Th/Yb, Ba/Th, and Ba/La ratios of the intrusions, the crust may have been derived from the melting of the fertile mantle wedge that was metasomatized by various amounts of slab-derived fluids

  1. The response of zircon in eclogite to metamorphism during the multi-stage evolution of the Huwan Shear Zone, China: Insights from Lu-Hf-U-Pb isotopic and trace-element geochemistry

    NASA Astrophysics Data System (ADS)

    Peters, T. J.; Ayers, J. C.; Gao, S.; Liu, X.

    2009-12-01

    We present whole-rock and in-situ zircon isotopic and trace-element data to constrain the nature and timing of protolith formation and metamorphism for eclogite samples from Sujiahe and Xiongdian in the Huwan Shear Zone, China. Whole-rock trace-element signatures include negative HFSE and positive LILE anomalies for all samples. The Sujiahe eclogite displays LREE enrichment with low 143Nd/144Nd and high 87Sr/86Sr ratios implying mantle melt interaction with a continental reservoir. Xiongdian samples display MORB-like flat or slightly depleted LREE profiles with a depleted mantle 143Nd/144Nd value and enriched oceanic-type 87Sr/86Sr ratio. These signatures support interpretations that eclogite protoliths are fragments of Palaeotethyan Ocean emplaced into a transitional ocean-continent environment. Sujiahe zircon grains display core-mantle ± rim textures. Core analyses display variably preserved concentric zoning, negative Eu anomalies, and Th/U ratios >0.18, indicating magmatic growth in equilibrium with plagioclase. A 206Pb/238U age peak between 419-381 Ma with ɛHf (t = 206Pb/238U age) values -2.8 to +11.0 is interpreted to represent zircon crystallization from a contaminated mantle melt ca. 419 Ma. Zircon mantles yield 206Pb/238U ages of 303-308 Ma, ɛHf values -10.0 to +6.4, and overlap chemically with core analyses, but with reduced Th and LREE contents. The bimodal 206Pb/238U age distribution for core and mantle analyses is likely due to resetting of the U-Pb isotopic system through metamorphic dissolution-reprecipitation. The diverse ɛHf values likely relate to involvement of an aged crustal source. Hf TDM ages are dominantly NeoProterozoic, implying involvement of Yangtze continental crust. Zircon rims display 206Pb/238U ages from 282-306 Ma, and flat HREE profiles, negative ɛHf values, reduced 176Lu/177Hf ratios, and Th/U ratios <0.04, indicating new zircon growth in equilibrium with garnet. Xiongdian eclogite zircon grains display complex textures in

  2. Mo-mineralized porphyries are relatively hydrous and differentiated: insights from the Permian-Triassic granitic complex in the Baituyingzi Mo-Cu district, eastern Inner Mongolia, NE China

    NASA Astrophysics Data System (ADS)

    Sun, Yan; Liu, Jianming; Zeng, Qingdong; Wang, Jingbin; Wang, Yuwang; Hu, Ruizhong; Zhou, Lingli; Wu, Guanbin

    2017-08-01

    Mo-Cu mineralization in the Baituyingzi district of eastern Inner Mongolia occurs within a granitic complex. This paper presents and discusses zircon U-Pb ages and whole-rock geochemical and Sr-Nd-Pb isotopic data from the granitic complex as potential indicators for porphyry Mo fertility. The U-Pb ages indicate that five units of the granitic complex were emplaced between 265.2 ± 0.7 and 246.5 ± 1.0 Ma. Constrained by crosscutting dikes, Mo-Cu mineralization was probably related to the Baituyingzi monzogranite porphyry dated at 248.2 ± 0.64 Ma. The intrusions belong to high-K calc-alkaline to shoshonitic series that are characterized by highly fractionated rare earth element (REE) patterns and strong enrichments of large ion lithophile elements, relative to high-field strength elements. Apart from the ˜246-Ma dike that shows negative ɛNd ( t) values (-14.9 to -13.1), the intrusions have ɛNd( t) values ranging from -3.9 to 1.0, relatively young depleted mantle model ages (811 to 1183 Ma), 206Pb/204Pb of 18.137-18.335, and 207Pb/204Pb of 15.591-15.625, which are consistent with a juvenile lower crustal origin. Among the intrusions, the ˜248-Ma porphyry and the ˜246-Ma dike show adakite-like characteristics (e.g., Sr/Y = 44.9-185) and listric-shaped REE patterns that indicate amphibole fractionation and a hydrous magma source. However, the porphyry exhibits a higher differentiation index (81.4-91.5) and a steeper REE profile (e.g., LaN/YbN = 25.6-87.0) than those of the ˜246-Ma dike, which suggests that it is highly differentiated. We propose that the complex was generated by the partial melting of juvenile mafic lower crust (containing minor old crustal relicts) that was triggered by collision between the North China Craton and Siberian Craton. As indicated by the Th/Nb, Th/Yb, Ba/Th, and Ba/La ratios of the intrusions, the crust may have been derived from the melting of the fertile mantle wedge that was metasomatized by various amounts of slab

  3. The O2-Evolving Complex of Photosystem II: Recent Insights from Quantum Mechanics/Molecular Mechanics (QM/MM), Extended X-ray Absorption Fine Structure (EXAFS), and Femtosecond X-ray Crystallography Data.

    PubMed

    Askerka, Mikhail; Brudvig, Gary W; Batista, Victor S

    2017-01-17

    Efficient photoelectrochemical water oxidation may open a way to produce energy from renewable solar power. In biology, generation of fuel due to water oxidation happens efficiently on an immense scale during the light reactions of photosynthesis. To oxidize water, photosynthetic organisms have evolved a highly conserved protein complex, Photosystem II. Within that complex, water oxidation happens at the CaMn4O5 inorganic catalytic cluster, the so-called oxygen-evolving complex (OEC), which cycles through storage "S" states as it accumulates oxidizing equivalents and produces molecular oxygen. In recent years, there has been significant progress in understanding the OEC as it evolves through the catalytic cycle. Studies have combined conventional and femtosecond X-ray crystallography with extended X-ray absorption fine structure (EXAFS) and quantum mechanics/molecular mechanics (QM/MM) methods and have addressed changes in protonation states of μ-oxo bridges and the coordination of substrate water through the analysis of ammonia binding as a chemical analog of water. These advances are thought to be critical to understanding the catalytic cycle since protonation states regulate the relative stability of different redox states and the geometry of the OEC. Therefore, establishing the mechanism for substrate water binding and the nature of protonation/redox state transitions in the OEC is essential for understanding the catalytic cycle of O2 evolution. The structure of the dark-stable S1 state has been a target for X-ray crystallography for the past 15 years. However, traditional X-ray crystallography has been hampered by radiation-induced reduction of the OEC. Very recently, a revolutionary X-ray free electron laser (XFEL) technique was applied to PSII to reveal atomic positions at 1.95 Å without radiation damage, which brought us closer than ever to establishing the ultimate structure of the OEC in the S1 state. However, the atom positions in this crystal

  4. BASS II

    NASA Image and Video Library

    2014-02-14

    ISS038-E-047576 (14 Feb. 2014) --- NASA astronaut Rick Mastracchio, Expedition 38 flight engineer, works with the Burning and Suppression of Solids (BASS-II) experiment in the Microgravity Science Glovebox (MSG) located in the Destiny laboratory of the International Space Station. BASS-II explores how different substances burn in microgravity with benefits for combustion on Earth and fire safety in space.

  5. BASS II

    NASA Image and Video Library

    2014-02-14

    ISS038-E-047582 (14 Feb. 2014) --- NASA astronaut Rick Mastracchio, Expedition 38 flight engineer, works with the Burning and Suppression of Solids (BASS-II) experiment in the Microgravity Science Glovebox (MSG) located in the Destiny laboratory of the International Space Station. BASS-II explores how different substances burn in microgravity with benefits for combustion on Earth and fire safety in space.

  6. Blocks of Archean material in the structure of the Uralian Platinum Belt: insights from in situ U-Pb (SHRIMP-II) data on zircon from the Nizhny Tagil clinopyroxenite-dunite complex

    NASA Astrophysics Data System (ADS)

    Malitch, K. N.; Efimov, A. A.; Ronkin, Yu. L.

    2009-04-01

    The Nizhny Tagil massif forms part of the 900-km-long Uralian Platinum Belt (UPB) and represents an undisputable example of a zoned Uralian-type clinopyroxenite-dunite complex (Efimov 1998; Auge et al. 2005). The 47 km2 Nizhny Tagil massif is almond-shape, shear bounded and enclosed by Riphean and Devonian metasediments to the west and late Paleozoic to Mesozoic predominantly mafic igneous rocks to the east. It consists of a platiniferrous dunite core (Fo92-90), surrounded by a clinopyroxenite rim. Recently obtained U-Pb and Sm-Nd isotope ages defined the range for UPB complexes between 540 and 425 Ma. Geochronological data for dunite remains scarce being restricted to the Kytlym dunite block (Bea et al. 2001). To fill this gap, we present the first results of uranium-lead ages for 10 grains of zircon, which were extracted by conventional techniques from course-grained dunite sampled at Alexandrovsky Log in the central part of the Nizhny Tagil massif. Most of zircons are subeuhedral, prismatic (80-170 microns long), with an elongation between 1.3 and 1.6, and oscillatory zoning characteristic of igneous rocks. Majority of zircons yield secondary inclusions; some grains show tracers of subdivision and recrystallization, whereas several grains are characterized by curved external counters pointing to specific condition of their evolution. U-Pb analyses were performed with secondary ion mass spectrometer SHRIMP II at VSEGEI, following the procedure described by Williams (1998). Concentrations of U vary from 34 to 520 ppm, Th from 18 to 358 ppm. Three age clusters have been determined. Two subordinate groups are characterized by concordant ages of 585±29 Ma (MSWD=1.07, probability (P) =0.30) and 1608±56 Ma (MSWD=0.07, P=0.79), whereas the main data set cluster around 2781±56 Ma. We assume, therefore, that the Late Archean age testifies the timing of dunite generation in subcontinental mantle, whereas the "youngest" U-Pb age might be linked with timing of formation

  7. Dreaming and insight

    PubMed Central

    Edwards, Christopher L.; Ruby, Perrine M.; Malinowski, Josie E.; Bennett, Paul D.; Blagrove, Mark T.

    2013-01-01

    This paper addresses claims that dreams can be a source of personal insight. Whereas there has been anecdotal backing for such claims, there is now tangential support from findings of the facilitative effect of sleep on cognitive insight, and of REM sleep in particular on emotional memory consolidation. Furthermore, the presence in dreams of metaphorical representations of waking life indicates the possibility of novel insight as an emergent feature of such metaphorical mappings. In order to assess whether personal insight can occur as a result of the consideration of dream content, 11 dream group discussion sessions were conducted which followed the Ullman Dream Appreciation technique, one session for each of 11 participants (10 females, 1 male; mean age = 19.2 years). Self-ratings of deepened self-perception and personal gains from participation in the group sessions showed that the Ullman technique is an effective procedure for establishing connections between dream content and recent waking life experiences, although wake life sources were found for only 14% of dream report text. The mean Exploration-Insight score on the Gains from Dream Interpretation questionnaire was very high and comparable to outcomes from the well-established Hill (1996) therapist-led dream interpretation method. This score was associated between-subjects with pre-group positive Attitude Toward Dreams (ATD). The need to distinguish “aha” experiences as a result of discovering a waking life source for part of a dream, from “aha” experiences of personal insight as a result of considering dream content, is discussed. Difficulties are described in designing a control condition to which the dream report condition can be compared. PMID:24550849

  8. Dreaming and insight.

    PubMed

    Edwards, Christopher L; Ruby, Perrine M; Malinowski, Josie E; Bennett, Paul D; Blagrove, Mark T

    2013-01-01

    This paper addresses claims that dreams can be a source of personal insight. Whereas there has been anecdotal backing for such claims, there is now tangential support from findings of the facilitative effect of sleep on cognitive insight, and of REM sleep in particular on emotional memory consolidation. Furthermore, the presence in dreams of metaphorical representations of waking life indicates the possibility of novel insight as an emergent feature of such metaphorical mappings. In order to assess whether personal insight can occur as a result of the consideration of dream content, 11 dream group discussion sessions were conducted which followed the Ullman Dream Appreciation technique, one session for each of 11 participants (10 females, 1 male; mean age = 19.2 years). Self-ratings of deepened self-perception and personal gains from participation in the group sessions showed that the Ullman technique is an effective procedure for establishing connections between dream content and recent waking life experiences, although wake life sources were found for only 14% of dream report text. The mean Exploration-Insight score on the Gains from Dream Interpretation questionnaire was very high and comparable to outcomes from the well-established Hill (1996) therapist-led dream interpretation method. This score was associated between-subjects with pre-group positive Attitude Toward Dreams (ATD). The need to distinguish "aha" experiences as a result of discovering a waking life source for part of a dream, from "aha" experiences of personal insight as a result of considering dream content, is discussed. Difficulties are described in designing a control condition to which the dream report condition can be compared.

  9. Comparison of NOx emissions from China III and China IV in-use diesel trucks based on on-road measurements

    NASA Astrophysics Data System (ADS)

    Yao, Zhiliang; Wu, Bobo; Wu, Yunong; Cao, Xinyue; Jiang, Xi

    2015-12-01

    To mitigate NOx and other emissions from diesel vehicles, China I, China II, China III and China IV emissions standards for new vehicles have been implemented nationwide. However, recent on-road measurements using a portable emission measurement system (PEMS) have revealed no significant reductions in the NOx emissions factors of diesel trucks due to the change from China II emissions standards to the more stringent China III standards. Thus, it is important to understand the effect of the China IV emissions standard on NOx emissions. In this study, nine China III and nine China IV diesel trucks of three sizes (light-duty diesel trucks (LDDTs), medium-duty diesel trucks (MDDTs) and heavy-duty diesel trucks (HDDTs)) were tested on real roads in Beijing using a PEMS. Compared to the tested China III diesel trucks, the China IV diesel trucks showed significant reductions of the average NOx emissions factors in terms of both distance travelled and fuel consumption. However, the driving conditions had an important impact on the reduction. Under non-highway driving (NHD), several of the tested China IV diesel trucks experienced no reduction or an increase in NOx emissions compared to their China III counterparts. The NOx emissions factors of the 18 tested diesel trucks under NHD were on average 1.5-times greater than those under highway driving (HD), and the effects on NOx emissions removal from China III to China IV diesel trucks were greater under HD than under NHD. In addition, no significant reduction of NOx based on fuel consumption for China IV diesel trucks was observed for MDDTs and HDDTs compared to the test results for similar China II vehicles reported in a previous study. To reduce NOx emissions in China, additional control measures of vehicular NOx emissions should be formulated.

  10. New Insights into Evolution.

    ERIC Educational Resources Information Center

    Stronck, David R.

    1992-01-01

    Presents insights on the controversial issues regarding evolution. This article partitions into the following sections: (1) Mechanisms explaining how evolution happened; (2) Creationist Confusion; (3) Literal Interpretation of the Bible; (4) Public demand for Creationism; (5) No Basis for Debating; and (6) Scientific Creationism is Bible Study.…

  11. Insight to Science

    ERIC Educational Resources Information Center

    Marshall, Dennis P.

    1978-01-01

    Describes the development and field-testing of Insight to Science, a science program for ages 11-13 developed by the Inner London Education Authority and published by Addison-Wesley. The program includes physical and life sciences and is intended as an introductory science experience. (CP)

  12. Changing Schools: Insights.

    ERIC Educational Resources Information Center

    Office of Policy and Planning (ED), Washington, DC.

    Over 1,000 communities in 45 states, territories, and the District of Columbia, are mobilized under the AMERICA 2000 banner to reach the 6 National Education Goals. This collection of papers, written by those who have wrestled with the process of school reform, offers useful insights to communities as they begin their process of transforming…

  13. New approaches to demystifying insight.

    PubMed

    Bowden, Edward M; Jung-Beeman, Mark; Fleck, Jessica; Kounios, John

    2005-07-01

    After a person has become stuck on a problem, they sometimes achieve a clear and sudden solution through insight--the so-called Aha! experience. Because of its distinctive experience, the origins and characteristics of insight have received considerable attention historically in psychological research. However, despite considerable progress in characterizing insight, the underlying mechanisms remain mysterious. We argue that research on insight could be greatly advanced by supplementing traditional insight research, which depends on a few complex problems, with paradigms common in other domains of cognitive science. We describe a large set of mini-insight problems to which multiple methods can be applied, together with subjective reports to identify insight problem-solving. Behavioral priming and neuroimaging methods are providing evidence about what, where, and how neural activity occurs during insight. Such evidence constrains theories of component processes, and will help to demystify insight.

  14. Photosystem II

    ScienceCinema

    James Barber

    2016-07-12

    James Barber, Ernst Chain Professor of Biochemistry at Imperial College, London, gives a BSA Distinguished Lecture titled, "The Structure and Function of Photosystem II: The Water-Splitting Enzyme of Photosynthesis."

  15. Delta II

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Delta II expendable launch vehicle with the ROSAT (Roentgen Satellite), cooperative space X-ray astronomy mission between NASA, Germany and United Kingdom, was launched from the Cape Canaveral Air Force Station on June 1, 1990.

  16. Death: 'nothing' gives insight.

    PubMed

    Ettema, Eric J

    2013-08-01

    According to a widely accepted belief, we cannot know our own death--death means 'nothing' to us. At first sight, the meaning of 'nothing' just implies the negation or absence of 'something'. Death then simply refers to the negation or absence of life. As a consequence, however, death has no meaning of itself. This leads to an ontological paradox in which death is both acknowledged and denied: death is … nothing. In this article, I investigate whether insight into the ontological paradox of the nothingness of death can contribute to a good end-of-life. By analysing Aquinas', Heidegger's and Derrida's understanding of death as nothingness, I explore how giving meaning to death on different ontological levels connects to, and at the same time provides resistance against, the harsh reality of death. By doing so, I intend to demonstrate that insight into the nothingness of death can count as a framework for a meaningful dealing with death.

  17. Update on INSIGHTS Development

    SciTech Connect

    Not Listed; Eric Burgett

    2011-09-01

    INSIGHTS is a transformational separate effects testing capability to perform in situ irradiation studies and characterization of the microscale behavior of nuclear fuel materials under a wide variety of in-pile conditions. Separate effects testing including growth, irradiation, and monitoring of these materials, and encompasses the full science based approach for fuels development from the nanoscale to the mesoscale behavior of the sample material and other defects driven by the modeling and simulation efforts of INL.

  18. The politics of insight

    PubMed Central

    Salvi, Carola; Cristofori, Irene; Grafman, Jordan; Beeman, Mark

    2016-01-01

    Previous studies showed that liberals and conservatives differ in cognitive style. Liberals are more flexible, and tolerant of complexity and novelty, whereas conservatives are more rigid, are more resistant to change, and prefer clear answers. We administered a set of compound remote associate problems, a task extensively used to differentiate problem-solving styles (via insight or analysis). Using this task, several researches have proven that self-reports, which differentiate between insight and analytic problem-solving, are reliable and are associated with two different neural circuits. In our research we found that participants self-identifying with distinct political orientations demonstrated differences in problem-solving strategy. Liberals solved significantly more problems via insight instead of in a step-by-step analytic fashion. Our findings extend previous observations that self-identified political orientations reflect differences in cognitive styles. More specifically, we show that type of political orientation is associated with problem-solving strategy. The data converge with previous neurobehavioural and cognitive studies indicating a link between cognitive style and the psychological mechanisms that mediate political beliefs. PMID:26810954

  19. China Reflections.

    ERIC Educational Resources Information Center

    Duval, Concetta

    1984-01-01

    A math and science high school director, who spent a month studying and traveling in China, comments on cultural differences observed during a visit to a day care center and during shopping trips and relates his experiences jogging during the early morning hours. (RM)

  20. Familial adenomatous polyposis in China

    PubMed Central

    Yang, Jun; Liu, Qing Wei; Li, Liang Wen; Wang, Qiang Zhi; Hong, Min; Dong, Jian

    2016-01-01

    Familial adenomatous polyposis (FAP) is an autosomal dominant disease with a poor prognosis, and has been studied by clinicians and geneticists in China for the past three decades. It is estimated that FAP has an incidence of between 1 in 8,000 and 1 in 10,000 individuals, and accounts for 0.94% of colorectal cancer cases in China. Recent advances in the understanding of FAP suggest that the genotype of the patient may allow for early diagnosis and surveillance, and guide surgical and chemopreventive management. However, the genetic mechanisms of FAP vary between different countries. FAP in China has its own characteristics, and this may be due to ethnic and geographical genetic variation. In the present review the clinical manifestations and genetics of FAP in China are discussed, as well as the surgical strategies, chemotherapeutics and traditional Chinese medicines used in its treatment. Increased insight into the genetic and clinical features of FAP in the Chinese population may aid in the prevention and management of the disorder. PMID:28105195

  1. Genetic diversity of Chinese rabies viruses: evidence for the presence of two distinct clades in China.

    PubMed

    Zhang, Yong-Zhen; Xiong, Cheng-Long; Lin, Xian-Dan; Zhou, Dun-Jin; Jiang, Ren-Jie; Xiao, Qi-You; Xie, Xin-Yao; Yu, Xiang-Xiang; Tan, You-Jiang; Li, Ming Hui; Ai, Quan-Shan; Zhang, Li-Jie; Zou, Yang; Huang, Chun; Fu, Zhen F

    2009-01-01

    There have been three major rabies epidemics in China since the 1950s. To gain more insights into the molecular epidemiology of rabies viruses (RVs) for the third (the current) epidemic, we isolated RV from dogs and humans in major endemic areas, and characterized these isolates genetically by sequencing the entire glycoprotein (G) gene and the G-L non-coding region. These sequences were also compared phylogenetically with RVs isolated in China during previous epidemics and those around the world. Comparison of the entire G genes among the Chinese isolates revealed up to 21.8% divergence at the nucleotide level and 17.8% at the amino acid level. The available Chinese isolates could be divided into two distinct clades, each of which could be further divided into six lineages. Viruses in clade I include most of the Chinese viruses as well as viruses from southeast Asian countries including Indonesia, Malaysia, the Philippines, Thailand, and Vietnam. The viruses in the other clade were found infrequently in China, but are closely related to viruses distributed worldwide among terrestrial animals. Interestingly, most of the viruses isolated during the past 10 years belong to lineage A viruses within clade I whereas most of the viruses isolated before 1996 belong to other lineages within clades I and II. Our results indicated that lineages A viruses have been predominant during the past 10 years and thus are largely responsible for the third and the current epidemic in China. Our results also suggested that the Chinese RV isolates in clade I share a common recent ancestor with those circulating in southeast Asia.

  2. FAQs II

    ERIC Educational Resources Information Center

    Kezar, Adrianna; Frank, Vikki; Lester, Jaime; Yang, Hannah

    2008-01-01

    In their paper entitled "Why should postsecondary institutions consider partnering to offer (Individual Development Accounts (IDAs)?" the authors reviewed frequently asked questions they encountered from higher education professionals about IDAs, but as their research continued so did the questions. FAQ II has more in-depth questions and…

  3. Gamma II

    NASA Astrophysics Data System (ADS)

    Barker, Thurburn; Castelaz, M.; Cline, J.; Owen, L.; Boehme, J.; Rottler, L.; Whitworth, C.; Clavier, D.

    2011-05-01

    GAMMA II is the Guide Star Automatic Measuring MAchine relocated from STScI to the Astronomical Photographic Data Archive (APDA) at the Pisgah Astronomical Research Institute (PARI). GAMMA II is a multi-channel laser-scanning microdensitometer that was used to measure POSS and SERC plates to create the Guide Star Catalog and the Digital Sky Survey. The microdensitometer is designed with submicron accuracy in x and y measurements using a HP 5507 laser interferometer, 15 micron sampling, and the capability to measure plates as large as 0.5-m across. GAMMA II is a vital instrument for the success of digitizing the direct, objective prism, and spectra photographic plate collections in APDA for research. We plan several targeted projects. One is a collaboration with Drs. P.D. Hemenway and R. L. Duncombe who plan to scan 1000 plates of 34 minor planets to identify systematic errors in the Fundamental System of celestial coordinates. Another is a collaboration with Dr. R. Hudec (Astronomical Institute, Academy of Sciences of the Czech Republic) who is working within the Gaia Variability Unit CU7 to digitize objective prism spectra on the Henize plates and Burrell-Schmidt plates located in APDA. These low dispersion spectral plates provide optical counterparts of celestial high-energy sources and cataclysmic variables enabling the simulation of Gaia BP/RP outputs. The astronomical community is invited to explore the more than 140,000 plates from 20 observatories now archived in APDA, and use GAMMA II. The process of relocating GAMMA to APDA, re-commissioning, and starting up the production scan programs will be described. Also, we will present planned research and future upgrades to GAMMA II.

  4. Modeling for Insights

    SciTech Connect

    Jacob J. Jacobson; Gretchen Matthern

    2007-04-01

    System Dynamics is a computer-aided approach to evaluating the interrelationships of different components and activities within complex systems. Recently, System Dynamics models have been developed in areas such as policy design, biological and medical modeling, energy and the environmental analysis, and in various other areas in the natural and social sciences. The real power of System Dynamic modeling is gaining insights into total system behavior as time, and system parameters are adjusted and the effects are visualized in real time. System Dynamic models allow decision makers and stakeholders to explore long-term behavior and performance of complex systems, especially in the context of dynamic processes and changing scenarios without having to wait decades to obtain field data or risk failure if a poor management or design approach is used. The Idaho National Laboratory recently has been developing a System Dynamic model of the US Nuclear Fuel Cycle. The model is intended to be used to identify and understand interactions throughout the entire nuclear fuel cycle and suggest sustainable development strategies. This paper describes the basic framework of the current model and presents examples of useful insights gained from the model thus far with respect to sustainable development of nuclear power.

  5. Molecular tracing of white muscardine in the silkworm, Bombyx mori (Linn.) II. Silkworm white muscardine is not caused by artificial release or natural epizootic of Beauveria bassiana in China.

    PubMed

    Chen, Xue; Huang, Cui; He, Lingmin; Zhang, Shengli; Li, Zengzhi

    2015-02-01

    The fungal pathogen Beauveria bassiana causes serious economic losses in sericulture. Its origin is usually attributed to the release of B. bassiana insecticides against pine caterpillars (Dendrolimus punctuatus). In the present study, 488 B. bassiana isolates obtained from silkworm (Bombyx mori) collected from 13 Chinese provinces, and 327 B. bassiana isolates obtained from D. punctatus collected from 9 provinces, were analyzed for population genetic structure using the ISSR technique based on genetic distance. A UPGMA dendrogram clustered them into three independent clades: two B. mori clades and one D. punctatus clade. A 3-D principal component analysis further divided them into two completely independent host groups, revealing high host-specificity. This suggested that white muscardine occurring in B. mori populations throughout southern China was not caused by any B. bassiana strain either naturally prevailing in D. punctatus populations or by any strain artificially released as a fungal insecticide against D. punctatus. We further investigated the genetic differentiation coefficient Gst and gene flow between B. mori-pathogenic and D. punctatus-pathogenic B. bassiana isolates from across China and from five provinces inhabited by both B. mori and D. punctatus. The Gst value across China was computed as 0.410, while the values of the five provinces ranged from 0.508 to 0.689; all above 0.25, which is the threshold for significant genetic differentiation. This suggests that B. bassiana strains isolated from the two different hosts maintained their respective heredity without a convergent homogenization trend, and reduces the possibility that the host range of the caterpillar isolates could expand and enhance their virulence in B. mori. These findings indicate that the use of B. bassiana does not threaten the safety of sericulture.

  6. Genetic diversity and differentiation of the rhesus macaque (Macaca mulatta) population in western Sichuan, China, based on the second exon of the major histocompatibility complex class II DQB (MhcMamu-DQB1) alleles.

    PubMed

    Yao, Yong-Fang; Dai, Qiu-Xia; Li, Jing; Ni, Qing-Yong; Zhang, Ming-Wang; Xu, Huai-Liang

    2014-06-14

    Rhesus macaques living in western Sichuan, China, have been separated into several isolated populations due to habitat fragmentation. Previous studies based on the neutral or nearly neutral markers (mitochondrial DNA or microsatellites) showed high levels of genetic diversity and moderate genetic differentiation in the Sichuan rhesus macaques. Variation at the major histocompatibility complex (MHC) loci is widely accepted as being maintained by balancing selection, even with a low level of neutral variability in some species. However, in small and isolated or bottlenecked populations, balancing selection may be overwhelmed by genetic drift. To estimate microevolutionary forces acting on the isolated rhesus macaque populations, we examined genetic variation at Mhc-DQB1 loci in 119 wild rhesus macaques from five geographically isolated populations in western Sichuan, China, and compared the levels of MHC variation and differentiation among populations with that previously observed at neutral microsatellite markers. 23 Mamu-DQB1 alleles were identified in 119 rhesus macaques in western Sichuan, China. These macaques exhibited relatively high levels of genetic diversity at Mamu-DQB1. The Hanyuan population presented the highest genetic variation, whereas the Heishui population was the lowest. Analysis of molecular variance (AMOVA) and pairwise FST values showed moderate genetic differentiation occurring among the five populations at the Mhc-DQB1 locus. Non-synonymous substitutions occurred at a higher frequency than synonymous substitutions in the peptide binding region. Levels of MHC variation within rhesus macaque populations are concordant with microsatellite variation. On the phylogenetic tree for the rhesus and crab-eating macaques, extensive allele or allelic lineage sharing is observed between the two species. Phylogenetic analyses confirm the apparent trans-species model of evolution of the Mhc-DQB1 genes in these macaques. Balancing selection plays an

  7. Genetic diversity and differentiation of the rhesus macaque (Macaca mulatta) population in western Sichuan, China, based on the second exon of the major histocompatibility complex class II DQB (MhcMamu-DQB1) alleles

    PubMed Central

    2014-01-01

    Abstracts Background Rhesus macaques living in western Sichuan, China, have been separated into several isolated populations due to habitat fragmentation. Previous studies based on the neutral or nearly neutral markers (mitochondrial DNA or microsatellites) showed high levels of genetic diversity and moderate genetic differentiation in the Sichuan rhesus macaques. Variation at the major histocompatibility complex (MHC) loci is widely accepted as being maintained by balancing selection, even with a low level of neutral variability in some species. However, in small and isolated or bottlenecked populations, balancing selection may be overwhelmed by genetic drift. To estimate microevolutionary forces acting on the isolated rhesus macaque populations, we examined genetic variation at Mhc-DQB1 loci in 119 wild rhesus macaques from five geographically isolated populations in western Sichuan, China, and compared the levels of MHC variation and differentiation among populations with that previously observed at neutral microsatellite markers. Results 23 Mamu-DQB1 alleles were identified in 119 rhesus macaques in western Sichuan, China. These macaques exhibited relatively high levels of genetic diversity at Mamu-DQB1. The Hanyuan population presented the highest genetic variation, whereas the Heishui population was the lowest. Analysis of molecular variance (AMOVA) and pairwise FST values showed moderate genetic differentiation occurring among the five populations at the Mhc-DQB1 locus. Non-synonymous substitutions occurred at a higher frequency than synonymous substitutions in the peptide binding region. Levels of MHC variation within rhesus macaque populations are concordant with microsatellite variation. On the phylogenetic tree for the rhesus and crab-eating macaques, extensive allele or allelic lineage sharing is observed betweenthe two species. Conclusions Phylogenetic analyses confirm the apparent trans-species model of evolution of the Mhc-DQB1 genes in these

  8. PORT II

    NASA Technical Reports Server (NTRS)

    Muniz, Beau

    2009-01-01

    One unique project that the Prototype lab worked on was PORT I (Post-landing Orion Recovery Test). PORT is designed to test and develop the system and components needed to recover the Orion capsule once it splashes down in the ocean. PORT II is designated as a follow up to PORT I that will utilize a mock up pressure vessel that is spatially compar able to the final Orion capsule.

  9. BORE II

    SciTech Connect

    2015-08-01

    Bore II, co-developed by Berkeley Lab researchers Frank Hale, Chin-Fu Tsang, and Christine Doughty, provides vital information for solving water quality and supply problems and for improving remediation of contaminated sites. Termed "hydrophysical logging," this technology is based on the concept of measuring repeated depth profiles of fluid electric conductivity in a borehole that is pumping. As fluid enters the wellbore, its distinct electric conductivity causes peaks in the conductivity log that grow and migrate upward with time. Analysis of the evolution of the peaks enables characterization of groundwater flow distribution more quickly, more cost effectively, and with higher resolution than ever before. Combining the unique interpretation software Bore II with advanced downhole instrumentation (the hydrophysical logging tool), the method quantifies inflow and outflow locations, their associated flow rates, and the basic water quality parameters of the associated formation waters (e.g., pH, oxidation-reduction potential, temperature). In addition, when applied in conjunction with downhole fluid sampling, Bore II makes possible a complete assessment of contaminant concentration within groundwater.

  10. The Contemporary Development of Philosophy of Education in Mainland China and Taiwan

    ERIC Educational Resources Information Center

    Shenghong, Jin; Dan, Jau-wei

    2004-01-01

    This article introduces and analyses recent developments in philosophy of education in mainland China and Taiwan. Though Confucianism has very rich insights into education, philosophy of education as a discipline came to China only around 100 years ago. It reached its first climax in the 1920s and 1930s, but then went into decline for nearly half…

  11. The Contemporary Development of Philosophy of Education in Mainland China and Taiwan

    ERIC Educational Resources Information Center

    Shenghong, Jin; Dan, Jau-wei

    2004-01-01

    This article introduces and analyses recent developments in philosophy of education in mainland China and Taiwan. Though Confucianism has very rich insights into education, philosophy of education as a discipline came to China only around 100 years ago. It reached its first climax in the 1920s and 1930s, but then went into decline for nearly half…

  12. Insights on STEM Careers

    SciTech Connect

    Wendelberger, Joanne Roth

    2014-11-05

    This presentation will provide career advice for individuals seeking to go beyond just having a job to building a successful career in the areas of Science, Technology, Engineering, and Mathematics. Careful planning can be used to turn a job into a springboard for professional advancement and personal satisfaction. Topics to be addressed include setting priorities, understanding career ladders, making tough choices, overcoming stereotypes and assumptions by others, networking, developing a professional identify, and balancing a career with family and other personal responsibilities. Insights on the transition from individual technical work to leadership will also be provided. The author will draw upon experiences gained in academic, industrial, and government laboratory settings, as well as extensive professional service and community involvement.

  13. Osho - Insights on sex

    PubMed Central

    Nagaraj, Anil Kumar Mysore

    2013-01-01

    Sex is a mysterious phenomenon, which has puzzled even great sages. Human beings have researched and mastered the biology of sex. But that is not all. Sex needs to be understood from the spiritual perspective too. The vision of Osho is an enlightening experience in this regard. Out of the thousands of lectures, five lectures on sex made Osho most notorious. Born into a Jain family of Madhya Pradesh, Rajneesh, who later wanted himself to be called Osho, is a great master. He has spoken volumes on a wide range of topics ranging from sex to super-consciousness. His contributions in the area of sex are based on the principles of “Tantra” which has its origin from Buddhism. This article focuses on his life and insights on sex, which if understood properly, can be a stepping stone for enlightenment. PMID:23858266

  14. Osho - Insights on sex.

    PubMed

    Nagaraj, Anil Kumar Mysore

    2013-01-01

    Sex is a mysterious phenomenon, which has puzzled even great sages. Human beings have researched and mastered the biology of sex. But that is not all. Sex needs to be understood from the spiritual perspective too. The vision of Osho is an enlightening experience in this regard. Out of the thousands of lectures, five lectures on sex made Osho most notorious. Born into a Jain family of Madhya Pradesh, Rajneesh, who later wanted himself to be called Osho, is a great master. He has spoken volumes on a wide range of topics ranging from sex to super-consciousness. His contributions in the area of sex are based on the principles of "Tantra" which has its origin from Buddhism. This article focuses on his life and insights on sex, which if understood properly, can be a stepping stone for enlightenment.

  15. Psychophysiological prediction of choice: relevance to insight and drug addiction.

    PubMed

    Moeller, Scott J; Hajcak, Greg; Parvaz, Muhammad A; Dunning, Jonathan P; Volkow, Nora D; Goldstein, Rita Z

    2012-11-01

    An important goal of addiction research and treatment is to predict behavioural responses to drug-related stimuli. This goal is especially important for patients with impaired insight, which can interfere with therapeutic interventions and potentially invalidate self-report questionnaires. This research tested (i) whether event-related potentials, specifically the late positive potential, predict choice to view cocaine images in cocaine addiction; and (ii) whether such behaviour prediction differs by insight (operationalized in this study as self-awareness of image choice). Fifty-nine cocaine abusers and 32 healthy controls provided data for the following laboratory components that were completed in a fixed-sequence (to establish prediction): (i) event-related potential recordings while passively viewing pleasant, unpleasant, neutral and cocaine images, during which early (400-1000 ms) and late (1000-2000 ms) window late positive potentials were collected; (ii) self-reported arousal ratings for each picture; and (iii) two previously validated tasks: one to assess choice for viewing these same images, and the other to group cocaine abusers by insight. Results showed that pleasant-related late positive potentials and arousal ratings predicted pleasant choice (the choice to view pleasant pictures) in all subjects, validating the method. In the cocaine abusers, the predictive ability of the late positive potentials and arousal ratings depended on insight. Cocaine-related late positive potentials better predicted cocaine image choice in cocaine abusers with impaired insight. Another emotion-relevant event-related potential component (the early posterior negativity) did not show these results, indicating specificity of the late positive potential. In contrast, arousal ratings better predicted respective cocaine image choice (and actual cocaine use severity) in cocaine abusers with intact insight. Taken together, the late positive potential could serve as a biomarker to

  16. Psychophysiological prediction of choice: relevance to insight and drug addiction

    PubMed Central

    Moeller, Scott J.; Hajcak, Greg; Parvaz, Muhammad A.; Dunning, Jonathan P.; Volkow, Nora D.

    2012-01-01

    An important goal of addiction research and treatment is to predict behavioural responses to drug-related stimuli. This goal is especially important for patients with impaired insight, which can interfere with therapeutic interventions and potentially invalidate self-report questionnaires. This research tested (i) whether event-related potentials, specifically the late positive potential, predict choice to view cocaine images in cocaine addiction; and (ii) whether such behaviour prediction differs by insight (operationalized in this study as self-awareness of image choice). Fifty-nine cocaine abusers and 32 healthy controls provided data for the following laboratory components that were completed in a fixed-sequence (to establish prediction): (i) event-related potential recordings while passively viewing pleasant, unpleasant, neutral and cocaine images, during which early (400–1000 ms) and late (1000–2000 ms) window late positive potentials were collected; (ii) self-reported arousal ratings for each picture; and (iii) two previously validated tasks: one to assess choice for viewing these same images, and the other to group cocaine abusers by insight. Results showed that pleasant-related late positive potentials and arousal ratings predicted pleasant choice (the choice to view pleasant pictures) in all subjects, validating the method. In the cocaine abusers, the predictive ability of the late positive potentials and arousal ratings depended on insight. Cocaine-related late positive potentials better predicted cocaine image choice in cocaine abusers with impaired insight. Another emotion-relevant event-related potential component (the early posterior negativity) did not show these results, indicating specificity of the late positive potential. In contrast, arousal ratings better predicted respective cocaine image choice (and actual cocaine use severity) in cocaine abusers with intact insight. Taken together, the late positive potential could serve as a biomarker

  17. Kashgar, China

    NASA Image and Video Library

    2016-12-12

    In far western China is Xinjiang Prefecture, with its capital of Kashgar (bottom right on image). The area has a rich history of over 2,000 years; Kashgar has served as a trading post and important city on the Silk Road. The folded sedimentary rocks outline valleys that contain oases, cultivated for thousands of years. The image was acquired 23 July 2014, covers an area of 37.3 by 46.3 kilometers, and is located at 39.8 degrees north, 75.8 degrees east. http://photojournal.jpl.nasa.gov/catalog/PIA21189

  18. PESTICINS II. I and II

    PubMed Central

    Brubaker, Robert R.; Surgalla, Michael J.

    1962-01-01

    Brubaker, Robert R. (Fort Detrick, Frederick, Md.) and Michael J. Surgalla. Pesticins. II. Production of pesticin I and II. J. Bacteriol. 84:539–545. 1962.—Pesticin I was separated from pesticin I inhibitor by ion-exchange chromatography of cell-free culture supernatant fluids and by acid precipitation of soluble preparations obtained from mechanically disrupted cells. The latter procedure resulted in formation of an insoluble pesticin I complex which, upon removal by centrifugation and subsequent dissolution in neutral buffer, exhibited a 100- to 1,000-fold increase in antibacterial activity over that originally observed. However, activity returned to the former level upon addition of the acid-soluble fraction, which contained pesticin I inhibitor. Since the presence of pesticin I inhibitor leads to serious errors in the determination of pesticin I, an assay medium containing ethylenediaminetetraacetic acid in excess Ca++ was developed; this medium eliminated the effect of the inhibitor. By use of the above medium, sufficient pesticin I was found to be contained within 500 nonirradiated cells to inhibit growth of a suitable indicator strain; at least 107 cells were required to effect a corresponding inhibition by pesticin II. Although both pesticins are located primarily within the cell during growth, pesticin I may arise extracellularly during storage of static cells. Slightly higher activity of pesticin I inhibitor was found in culture supernatant fluids than occurred in corresponding cell extracts of equal volume. The differences and similarities between pesticin I and some known bacteriocins are discussed. PMID:14016110

  19. Single molecule studies of RNA polymerase II transcription in vitro

    PubMed Central

    Horn, Abigail E; Goodrich, James A; Kugel, Jennifer F

    2014-01-01

    Eukaryotic mRNA transcription by RNA polymerase II (RNAP II) is the first step in gene expression and a key determinant of cellular regulation. Elucidating the mechanism by which RNAP II synthesizes RNA is therefore vital to determining how genes are controlled under diverse biological conditions. Significant advances in understanding RNAP II transcription have been achieved using classical biochemical and structural techniques; however, aspects of the transcription mechanism cannot be assessed using these approaches. The application of single-molecule techniques to study RNAP II transcription has provided new insight only obtainable by studying molecules in this complex system one at a time. PMID:25764112

  20. Single molecule studies of RNA polymerase II transcription in vitro.

    PubMed

    Horn, Abigail E; Goodrich, James A; Kugel, Jennifer F

    2014-01-01

    Eukaryotic mRNA transcription by RNA polymerase II (RNAP II) is the first step in gene expression and a key determinant of cellular regulation. Elucidating the mechanism by which RNAP II synthesizes RNA is therefore vital to determining how genes are controlled under diverse biological conditions. Significant advances in understanding RNAP II transcription have been achieved using classical biochemical and structural techniques; however, aspects of the transcription mechanism cannot be assessed using these approaches. The application of single-molecule techniques to study RNAP II transcription has provided new insight only obtainable by studying molecules in this complex system one at a time.

  1. Education in China

    ERIC Educational Resources Information Center

    Fengzhen, Yang

    2002-01-01

    In the past 20 years, China's economy has been developing rapidly. Yet is China's education keeping up the same pace as its economic development? What is the current situation for China's education? With the advent of knowledge-based economy, how will education in China adjust itself in order to meet the growing demands of economy? This paper will…

  2. Differential effect of solution conditions on the conformation of the actinoporins Sticholysin II and Equinatoxin II.

    PubMed

    Fauth, Edson V F; Cilli, Eduardo M; Ligabue-Braun, Rodrigo; Verli, Hugo

    2014-12-01

    Actinoporins are a family of pore-forming proteins with hemolytic activity. The structural basis for such activity appears to depend on their correct folding. Such folding encompasses a phosphocholine binding site, a tryptophan-rich region and the activity-related N-terminus segment. Additionally, different solution conditions are known to be able to influence the pore formation by actinoporins, as for Sticholysin II (StnII) and Equinatoxin II (EqtxII). In this context, the current work intends to characterize the influence of distinct solution conditions in the conformational behavior of these proteins through molecular dynamics (MD) simulations. The obtained data offer structural insights into actinoporins dynamics in solution, characterizing its conformational behavior at the atomic level, in accordance with previous experimental data on StnII and EqtxII hemolytic activities.

  3. China's health assistance to Africa: opportunism or altruism?

    PubMed

    Lin, Shuang; Gao, Liangmin; Reyes, Melissa; Cheng, Feng; Kaufman, Joan; El-Sadr, Wafaa M

    2016-12-03

    China has made substantial health commitments to Africa in the past several decades. However, while much has been written regarding China-Africa aid overall, relatively little attention has been given to China's health aid. To better understand these investments, we provide an overview of the current framework and characteristics of China's health aid to Africa. China's health assistance has been perceived by some as opportunistic, largely as a demonstration of China's engagement in "soft power" and an attempt to enhance its access to natural resources and political favors by African countries. Others have attributed altruistic intent, aiming to support the advancement of the health of populations in the African continent with a "no strings attached" approach. Our overview demonstrated that despite the magnitude of China's health assistance, many questions remain regarding the scope of this aid, its effectiveness and the governance mechanisms that guide the conceptualization and implementation of such efforts. We also identified the need for a systematic and rigorous evaluation of the various elements of China's health assistance to African countries in order to gain a deeper understanding of how priorities and allocations for health aid are determined, how such aid fits within the specific African country's health strategies and to assess the effectiveness of such aid. Insights garnered through such an assessment could help determine future priorities for investment as well as inform efforts to optimize the value of China's aid for the populations of the recipient countries.

  4. China Energy Primer

    SciTech Connect

    Ni, Chun Chun

    2009-11-16

    Based on extensive analysis of the 'China Energy Databook Version 7' (October 2008) this Primer for China's Energy Industry draws a broad picture of China's energy industry with the two goals of helping users read and interpret the data presented in the 'China Energy Databook' and understand the historical evolution of China's energy inustry. Primer provides comprehensive historical reviews of China's energy industry including its supply and demand, exports and imports, investments, environment, and most importantly, its complicated pricing system, a key element in the analysis of China's energy sector.

  5. Liver transplantation for hepatocellular carcinoma: recent advances in China.

    PubMed

    Lu, Tian Fei; Hua, Xiang Wei; Cui, Xiao Lan; Xia, Qiang

    2014-02-01

    Orthotopic liver transplantation is currently the best treatment option for selected patients with hepatocellular carcinoma (HCC). From 1980 to 2011, 8874 patients with HCC in China underwent liver transplantation. The organ donation classification criteria of China (China criteria), which are established by the Government of China, are divided into three parts: China criteria I, donation after brain death; China criteria II, donation after cardiac death and China criteria III, donation after dual brain-cardiac death. Data from the China Liver Transplant Registry(CLTR) System shows that patients within the Milan criteria have higher survival rates than those who are beyond these criteria. Based on CLTR data, altogether 416 patients received living-donor liver transplantation(LDLT) in China. Their 1-year and 3-year survival rates were significantly higher than those of the non-LDLT recipients. The most common early stage(<30 days after liver transplantation) complications include pleural effusion, diabetes, peritoneal effusion or abscess, postoperative infection, hypertension and intraperitoneal hemorrhage; while the most common late stage (≥ 30 days after liver transplantation) complications were diabetes, hypertension, biliary complications,postoperative infection, tacrolimus toxicity and chronic graft rejection. The incidence of vascular complication, which is the main reason for acute graft failure and re-transplantation, was 2.4%. Liver transplantation is an effective treatment for patients with HCC in China.

  6. Mission Operations Insights

    NASA Technical Reports Server (NTRS)

    Littman, Dave; Parksinson, Lou

    2006-01-01

    The mission description Polar Operational Environmental Satellites (POES): I) Collect and disseminate worldwide meteorological and environmental data: a) Provide day and night information (AVHRR): 1) cloud cover distribution and type; 2) cloud top temperature; 3) Moisture patterns and ice/snow melt. b) Provide vertical temperature and moisture profiles of atmospheres (HIRS, AMSU, MHS. c) Measure global ozone distribution and solar UV radiation (SBUV). d) Measure proton, electro, and charged particle density to provide solar storm warnings (SEM). d) Collect environmental data (DCS): 1) Stationary platforms in remote locations; 2) Free floating platforms on buoys, balloons, migratory animals. II) Provide Search and Rescue capabilities (SARR, SARP): a) Detection and relay of distress signals. b) Has saved thousands of lives around the world.

  7. Cognitive insight: A systematic review.

    PubMed

    Van Camp, L S C; Sabbe, B G C; Oldenburg, J F E

    2017-07-01

    Cognitive insight is the ability to re-evaluate thoughts and beliefs in order to make thoughtful conclusions. It differs from clinical insight, as it focuses on more general metacognitive processes. Therefore, it could be relevant to diverse disorders and non-clinical subjects. There is a growing body of research on cognitive insight in individuals with and without psychosis. This review has summarised the current state of the art regarding this topic. We conclude that while cognitive insight in its current form seems valid for use in individuals with psychosis, it is less so for individuals without psychosis. Additionally, higher cognitive insight not always leads to better psychological functioning. For instance, higher levels of self-reflection are often associated with depressive mood. We therefore recommend the sub-components of cognitive insight to be studied separately. Also, it is unclear what position cognitive insight takes within the spectrum of metacognitive processes and how it relates to other self-related concepts that have been defined previously in literature. Combining future and past research on cognitive insight and its analogue concepts will help in the formation of a uniform definition that fits all subjects discussed here. Copyright © 2017. Published by Elsevier Ltd.

  8. Grigor Narekatsi's astronomical insights

    NASA Astrophysics Data System (ADS)

    Poghosyan, Samvel

    2015-07-01

    What stand out in the solid system of Gr. Narekatsi's naturalistic views are his astronomical insights on the material nature of light, its high speed and the Sun being composed of "material air". Especially surprising and fascinating are his views on stars and their clusters. What astronomers, including great Armenian academician V. Ambartsumian (scattering of stellar associations), would understand and prove with much difficulty thousand years later, Narekatsi predicted in the 10th century: "Stars appear and disappear untimely", "You who gather and scatter the speechless constellations, like a flock of sheep". Gr. Narekatsti's reformative views were manifested in all the spheres of the 10th century social life; he is a reformer of church life, great language constructor, innovator in literature and music, freethinker in philosophy and science. His ideology is the reflection of the 10th century Armenian Renaissance. During the 9th-10th centuries, great masses of Armenians, forced to migrate to the Balkans, took with them and spread reformative ideas. The forefather of the western science, which originated in the period of Reformation, is considered to be the great philosopher Nicholas of Cusa. The study of Gr. Narekatsti's logic and naturalistic views enables us to claim that Gr. Narekatsti is the great grandfather of European science.

  9. Systemic sclerosis: Recent insights.

    PubMed

    Elhai, Muriel; Avouac, Jérôme; Kahan, André; Allanore, Yannick

    2015-05-01

    Systemic sclerosis is an orphan connective tissue disease characterized by alterations of the microvasculature, disturbances of the immune system and massive deposition of collagen and other matrix substances in the skin and internal organs. A major achievement of the recent years has been the validation of new classification criteria, allowing earlier diagnosis and earlier treatment of systemic sclerosis, before irreversible fibrosis and organ damage appeared ("window of opportunity"). Raynaud's phenomenon is usually the first sign of the disease and is considered as the main sentinel sign for the identification of very early systemic sclerosis. Systemic sclerosis is clinically heterogeneous and disease course remains unpredictable. Its prognosis depends on cardiopulmonary involvement and recent studies aim to identify serum or genetic biomarkers predictive of severe organ involvement. Moreover, the prospective follow-up of large cohorts has provided and will offer critical material to identify strong prognostic factors. Whereas the outcomes of vascular manifestations of the disease has been recently improved due to targeted therapy, recent data have highlighted that mortality has not changed over the past 40 years. This reflects the absence of efficacy of current available drugs to counteract the fibrotic process. Nevertheless, several targeted immunity therapies, commonly with proven efficacy in other immune diseases, are about to be investigated in systemic sclerosis. Indeed, promising results in small and open studies have been reported. This article deals with recent insights into classification criteria, pathogenesis, organ involvements, outcome and current and possible future therapeutic options in systemic sclerosis.

  10. China opens the door

    SciTech Connect

    Starke, K.

    1997-01-01

    The door to China`s vast market for power generation was opened a bit further for foreign firms in November. That is when power ministry head Shi Dazhen said the country would rely on overseas investors for 20 percent of the funding needed to boost output--double the amount foreigners were previously allowed to contribute. Through 1995, foreigners invested $12.2 billion in China`s electricity industry, accounting for 10 percent of total investment. According to Shi, foreign investors will be asked to provide about $17 billion of the $84 billion China plans to invest in the sector over the next five years. Under China`s Ninth Five-Year Plan (1996-2000), the government aims to boost the country`s power generation capacity at the rate of 15,000 MW to 20,000 MW annually by the year 2000. Since China`s public external debt balance already exceeds $80 billion, however, the government would seem to have little choice but to allow foreigners a greater role. Shi also said that foreigners would be allowed 100 percent ownership of PRC power projects. This is discouraged under China`s current industry guidelines. It is, however, expected to be permitted under China`s first build-operate-transfer (BOT) law, which was anticipated by the end of 1996, says Susan Urkevich, director of project finance at HSBC Investment Bank Asia in Hong Kong. Indeed, China`s first BOT is already happening.

  11. Effects of traditional Chinese medicine on rats with Type II diabetes induced by high-fat diet and streptozotocin: a urine metabonomic study.

    PubMed

    Zhao, Huihui; Li, Zhigeng; Tian, Guihua; Gao, Kuo; Li, Zhiyong; Zhao, Baosheng; Wang, Juan; Luo, Liangtao; Pan, Qiu; Zhang, Wenting; Wu, Zhiqian; Chen, Jianxin; Wang, Wei

    2013-09-01

    Type II diabetes has become a serious threat to human health in recent years. Among adults above 20 years old in China, the prevalence rate of diabetes is 9.7%. Thus, it is imperative to study the mechanisms underlying type II diabetes to develop effective therapeutic treatments. To examine metabolic changes in a rat model of type II diabetes and explore mechanisms underlying the beneficial effects of traditional Chinese medicine (TCM) in this model. 120 rats were divided into four groups, including a control group, a high-fat diet group (high-fat diet and streptozotocin injection), a TCM group (high-fat diet, streptozotocin injection, followed by TCM administration), and a rosiglitazone maleate group (high-fat diet, streptozotocin injection, followed by rosiglitazone maleate administration). Metabolites in urine samples from 1-3 weeks (time point 1) and 4-6 weeks (time point 2) of drug administration were compared by gas chromatography-mass spectrometry (GC-MS). Our results showed that in the high-fat diet group, at time point 2, the levels of dihydroxybenzoic acid, L-ascorbic acid, D-gluconic acid, octadecanoic acid, and glutaric acid in urine were significantly higher than at time point 1. In the TCM group, at time point 2, the urine levels of L-ascorbic acid were markedly lower than at time point 1. Our studies demonstrated that examining urine metabolic changes provided important insights into the mechanisms underlying type II diabetes as well as the therapeutic effects of TCM.

  12. The Neurocircuitry of Impaired Insight in Drug Addiction

    SciTech Connect

    Goldstein, R.Z.; Craig, A.D.; Bechara, A.; Garavan, H.; Childress, A.R.; Paulus, M.P.; Volkow, N.D.

    2009-08-27

    More than 80% of addicted individuals fail to seek treatment, which might reflect impairments in recognition of severity of disorder. Considered by some as intentional deception, such 'denial' might instead reflect dysfunction of brain networks subserving insight and self-awareness. Here we review the scant literature on insight in addiction and integrate this perspective with the role of: (i) the insula in interoception, self-awareness and drug craving; (ii) the anterior cingulate in behavioral monitoring and response selection (relevant to disadvantageous choices in addiction); (iii) the dorsal striatum in automatic habit formation; and (iv) drug-related stimuli that predict emotional behavior in addicted individuals, even without conscious awareness. We discuss implications for clinical treatment including the design of interventions to improve insight into illness severity in addiction.

  13. Vertical distribution of Fe and Fe(III)-reducing bacteria in the sediments of Lake Donghu, China.

    PubMed

    Tian, Cuicui; Wang, Chunbo; Tian, Yingying; Wu, Xingqiang; Xiao, Bangding

    2015-08-01

    In lake sediments, iron (Fe) is the most versatile element, and the redox cycling of Fe has a wide influence on the biogeochemical cycling of organic and inorganic substances. The aim of the present study was to analyze the vertical distribution of Fe and Fe(III)-reducing bacteria (FeRB) in the surface sediment (30 cm) of Lake Donghu, China. At the 3 sites we surveyed, FeRB and Fe(II)-oxidizing bacteria (FeOB) coexisted in anoxic sediments. Geobacter-related FeRB accounted for 5%-31% of the total Bacteria, while Gallionella-related FeOB accounted for only 0.1%-1.3%. A significant correlation between the relative abundance of poorly crystalline Fe and Geobacter spp. suggested that poorly crystalline Fe favored microbial Fe(III) reduction. Poorly crystalline Fe and Geobacter spp. were significantly associated with solid-phase Fe(II) and total inorganic phosphorus levels. Pore water Fe(II) concentrations negatively correlated with NO3(-) at all sites. We concluded that Geobacter spp. were abundant in the sediments of Lake Donghu, and the redox of Fe might participate in the cycling of nitrogen and phosphorus in sediments. These observations provided insight into the roles of microbial Fe cycling in lake sediments.

  14. ICT, complementary investment, and firm performance in China

    NASA Astrophysics Data System (ADS)

    Sun, Linlin; Ding, Juan; Fan, Maoqing

    2011-12-01

    Using China firm data about ICT, we provide some insight into the link between ICT, productivity and complementary investment. The results show that the contribution of ICT capital deepening is raised when firms combine ICT use and some complementary investment (human capital, innovation and organization change).

  15. Enigmatic insight into collagen

    PubMed Central

    Deshmukh, Shrutal Narendra; Dive, Alka M; Moharil, Rohit; Munde, Prashant

    2016-01-01

    Collagen is a unique, triple helical molecule which forms the major part of extracellular matrix. It is the most abundant protein in the human body, representing 30% of its dry weight. It is the fibrous structural protein that makes up the white fibers (collagen fibers) of skin, tendons, bones, cartilage and all other connective tissues. Collagens are not only essential for the mechanical resistance and resilience of multicellular organisms, but are also signaling molecules defining cellular shape and behavior. The human body has at least 16 types of collagen, but the most prominent types are I, II and III. Collagens are produced by several cell types and are distinguishable by their molecular compositions, morphologic characteristics, distribution, functions and pathogenesis. This is the major fibrous glycoprotein present in the extracellular matrix and in connective tissue and helps in maintaining the structural integrity of these tissues. It has a triple helical structure. Various studies have proved that mutations that modify folding of the triple helix result in identifiable genetic disorders. Collagen diseases share certain similarities with autoimmune diseases, because autoantibodies specific to each collagen disease are produced. Therefore, this review highlights the role of collagen in normal health and also the disorders associated with structural and functional defects in collagen. PMID:27601823

  16. Recent Neurobiological Insights into the Concept of Insight in Psychosis

    PubMed Central

    Mythri, Starlin Vijay; Sanjay, Y

    2016-01-01

    The concept of insight in psychosis has been an interesting area in clinical psychiatry for well over a century with a surge in research interest over the past 25 years. Moreover, the past 5 years have been particularly fruitful in deciphering its neurobiological underpinnings. This article presents the development of the concept of insight in psychosis and reviews the current neurobiological research findings in this area. PMID:27335512

  17. Modeling dry and wet deposition of sulfate, nitrate, and ammonium ions in Jiuzhaigou National Nature Reserve, China using a source-oriented CMAQ model: Part II. Emission sector and source region contributions.

    PubMed

    Qiao, Xue; Tang, Ya; Kota, Sri Harsha; Li, Jingyi; Wu, Li; Hu, Jianlin; Zhang, Hongliang; Ying, Qi

    2015-11-01

    A source-oriented Community Multiscale Air Quality (CMAQ) model driven by the meteorological fields generated by the Weather Research and Forecasting (WRF) model was used to study the dry and wet deposition of nitrate (NO3(-)), sulfate (SO4(2-)), and ammonium (NH4(+)) ions in the Jiuzhaigou National Nature Reserve (JNNR), China from June to August 2010 and to identify the contributions of different emission sectors and source regions that were responsible for the deposition fluxes. Contributions from power plants, industry, transportation, domestic, biogenic, windblown dust, open burning, fertilizer, and manure management sources to deposition fluxes in JNNR watershed and four EANET sites are determined. In JNNR, 96%, 82%, and 87% of the SO4(2-), NO3(-) and NH4(+) deposition fluxes are in the form of wet deposition of the corresponding aerosol species. Industry and power plants are the two major sources of SO4(2-) deposition flux, accounting for 86% of the total wet deposition of SO4(2-), and industry has a higher contribution (56%) than that of power plants (30%). Power plants and industry are also the top sources that are responsible for NO3(-) wet deposition, and contributions from power plants (30%) are generally higher than those from industries (21%). The major sources of NH4(+) wet deposition flux in JNNR are fertilizer (48%) and manure management (39%). Source-region apportionment confirms that SO2 and NOx emissions from local and two nearest counties do not have a significant impact on predicted wet deposition fluxes in JNNR, with contributions less than 10%. While local NH3 emissions account for a higher fraction of the NH4(+) deposition, approximately 70% of NH4(+) wet deposition in JNNR originated from other source regions. This study demonstrates that S and N deposition in JNNR is mostly from long-range transport rather than from local emissions, and to protect JNNR, regional emission reduction controls are needed.

  18. The RNA polymerase II elongation complex.

    PubMed

    Aso, T; Conaway, J W; Conaway, R C

    1995-11-01

    The initiation stage of transcription by RNA polymerase II has long been regarded as the primary site for regulation of eukaryotic gene expression. Nevertheless, a growing body of evidence reveals that the RNA polymerase II elongation complex is also a major target for regulation. Biochemical studies are implicating an increasing number of transcription factors in the regulation of elongation, and these transcription factors are being found to function by a diverse collection of mechanisms. Moreover, unexpected features of the structure and catalytic mechanism of RNA polymerase II are forcing a reconsideration of long-held views on the mechanics of some of the most basic aspects of polymerase function. In this review, we will describe recent insights into the structures and functions of RNA polymerase II and the transcription factors that control its activity during the elongation stage of eukaryotic messenger RNA synthesis.

  19. Baiyun Ebo, China

    NASA Image and Video Library

    2012-04-11

    Acquired by NASA Terra spacecraft, this image shows a mine in Baiyun Ebo, Inner Mongolia, China, the site of almost half the world rare earth production. China is responsible for over 95% of global production of rare earth elements.

  20. China and Korea

    Atmospheric Science Data Center

    2013-04-16

    ... article title:  Dust Obscures Liaoning Province, China     View Larger Image ... the deserts of China and Mongolia over great distances, and pollution from agriculture, industry and power generation is also carried ...

  1. China Report, Economic Affairs.

    DTIC Science & Technology

    2007-11-02

    This is China Report include Economic Affairs. It contains the issues with different topics on People’s Republic of China: Provincial Affairs, Economic Planning, Economic Management, Finance and Banking, Mineral Resources , Industry, Transportation.

  2. China Report, Economic Affairs.

    DTIC Science & Technology

    2007-11-02

    This is China Report include Economic Affairs. It contains the issues with different topics on People’s Republic of China: National Policy and Issues, Finance and Banking, Mineral Resources , Domestic Trade, Foreign Trade.

  3. China's ballistic missile program

    NASA Astrophysics Data System (ADS)

    Weder, M.

    1982-04-01

    Progress in China's development of ballistic missiles and satellite launching rockets is discussed. Historical background material is provided and several missiles are described. The missile program plans are discussed and an evaluation of China's nuclear capabilities is given.

  4. Picroside II protects against sepsis via suppressing inflammation in mice

    PubMed Central

    Huang, Ying; Zhou, Miao; Li, Chengbao; Chen, Yuanli; Fang, Wei; Xu, Guo; Shi, Xueyin

    2016-01-01

    Picroside II, an iridoid compound extracted from Picrorhiza, exhibits anti-inflammatory and anti-apoptotic activities. We explored the protective effects and mechanisms of picroside II in a mouse model of sepsis induced by cecal ligation and puncture (CLP), using three groups of mice: Group A (sham), Group B (CLP+NS) and Group C (CLP+20 mg/kg picroside II). The mortality in mice with sepsis was decreased by the administration of picroside II, and lung injury was alleviated simultaneously. Picroside II treatment enhanced bacterial clearance in septic mice. Further, picroside II treatment alleviated the inflammatory response in sepsis and enhanced immune function by inhibiting the activation of NLRP3 inflammasome and NF-κB pathways. Picroside II may represent an anti-inflammatory drug candidate, providing novel insight into the treatment of sepsis. PMID:28078023

  5. Doing Business with China.

    ERIC Educational Resources Information Center

    Department of Commerce, Washington, DC. Industry and Trade Administration.

    This publication provides background and practical information for those interested in doing business with China. The United States officially recognized the People's Republic of China (PRC) on January 1, 1979. Chinese leaders view international trade as an important factor in transforming China into a modern industrial state as well as an…

  6. Education in China.

    ERIC Educational Resources Information Center

    Ministry of Education (Republic of China).

    This book provides a comprehensive view of education in the People's Republic of China today. Divided into four sections, the bulk of the book's material is covered in the first section, "Education in China." Section 1 begins with a discussion of educational achievements in China, the present educational situation and basic conditions in…

  7. Aging in China.

    ERIC Educational Resources Information Center

    Sheppard, Harold L.; Streib, Gordon F.

    This document consists of facts and impressions gathered during 1984, in the course of an 18-day visit to the Peoples Republic of China by a team of epidemiologists and gerontologists from the United States. The major portion of the paper presents demographic, economic, and social perspectives on aging in China. It is noted that China remains a…

  8. China?s growing appetite for minerals

    USGS Publications Warehouse

    Menzie, David; Tse, Pui-Kwan; Fenton, Mike; Jorgenson, John; van Oss, Hendrik

    2004-01-01

    During the last 15 years, China's economy and consumption have grown rapidly. This report contains figures and notes from a talk that discusses China's increasing consumption of aluminum, cement, coal, copper, iron ore, petroleum, and steel in context of its developing economy.

  9. Gerst during BASS-II experiment

    NASA Image and Video Library

    2014-07-30

    ISS040-E-083576 (30 July 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, performs two tests with a combustion experiment known as the Burning and Suppression of Solids (BASS-II) in the Microgravity Science Glovebox (MSG) in the Destiny laboratory of the International Space Station. The experiment seeks to provide insight on how flames burn in space compared to Earth which may provide fire safety benefits aboard future spacecraft.

  10. Gerst during BASS-II experiment

    NASA Image and Video Library

    2014-07-30

    ISS040-E-083578 (30 July 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, performs two tests with a combustion experiment known as the Burning and Suppression of Solids (BASS-II) in the Microgravity Science Glovebox (MSG) in the Destiny laboratory of the International Space Station. The experiment seeks to provide insight on how flames burn in space compared to Earth which may provide fire safety benefits aboard future spacecraft.

  11. Three legacies of humanitarianism in China.

    PubMed

    Hirono, Miwa

    2013-10-01

    The rise of China has altered the context of the international humanitarian community of donors and aid agencies. China is becoming one of the key actors in this grouping, undertaking infrastructure projects in areas in which paramount humanitarian challenges exist. The literature discusses how the Chinese approach differs from that of Western donors, but it does not pay much attention to why China concentrates