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Sample records for active site gorge

  1. Energetics of Ortho-7 (oxime drug translocation through the active-site gorge of tabun conjugated acetylcholinesterase.

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    Vivek Sinha

    Full Text Available Oxime drugs translocate through the 20 Å active-site gorge of acetylcholinesterase in order to liberate the enzyme from organophosphorus compounds' (such as tabun conjugation. Here we report bidirectional steered molecular dynamics simulations of oxime drug (Ortho-7 translocation through the gorge of tabun intoxicated enzyme, in which time dependent external forces accelerate the translocation event. The simulations reveal the participation of drug-enzyme hydrogen bonding, hydrophobic interactions and water bridges between them. Employing nonequilibrium theorems that recovers the free energy from irreversible work done, we reconstruct potential of mean force along the translocation pathway such that the desired quantity represents an unperturbed system. The potential locates the binding sites and barriers for the drug to translocate inside the gorge. Configurational entropic contribution of the protein-drug binding entity and the role of solvent translational mobility in the binding energetics is further assessed.

  2. The Ironbridge Gorge Heritage Site and its local and regional functions

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    Cudny Waldemar

    2017-06-01

    Full Text Available The article is devoted to the issue of heritage and its functions. Based on the existing literature, the author presents the definition of heritage, the classification of heritage resources, and its most important impacts. The aim of the article was to show the functions that may be performed by a heritage site, locally and regionally. The example used by the author is the Ironbridge Gorge Heritage Site in the United Kingdom. Most heritage functions described by other authors are confirmed in this case study. The cultural heritage of the Ironbridge Gorge creates an opportunity to undertake various local and regional activities, having first of all an educational influence on the inhabitants, school youth and tourists. We must not ignore the economicinfluences, such as financing the activity of the Ironbridge Trust (the institution administering the site, generating income for local firms providing service to tourists, or for construction companies. This income helps to preserve and conserve the tangible heritage of the Ironbridge Gorge, as well as to generate jobs in heritage management, conservation and heritage tourism. Other effects of the Ironbridge Gorge Site include a socio-cultural impact or that related to sustainable development.

  3. A new horned crocodile from the Plio-Pleistocene hominid sites at Olduvai Gorge, Tanzania.

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    Christopher A Brochu

    Full Text Available BACKGROUND: The fossil record reveals surprising crocodile diversity in the Neogene of Africa, but relationships with their living relatives and the biogeographic origins of the modern African crocodylian fauna are poorly understood. A Plio-Pleistocene crocodile from Olduvai Gorge, Tanzania, represents a new extinct species and shows that high crocodylian diversity in Africa persisted after the Miocene. It had prominent triangular "horns" over the ears and a relatively deep snout, these resemble those of the recently extinct Malagasy crocodile Voay robustus, but the new species lacks features found among osteolaemines and shares derived similarities with living species of Crocodylus. METHODOLOGY/PRINCIPAL FINDINGS: The holotype consists of a partial skull and skeleton and was collected on the surface between two tuffs dated to approximately 1.84 million years (Ma, in the same interval near the type localities for the hominids Homo habilis and Australopithecus boisei. It was compared with previously-collected material from Olduvai Gorge referable to the same species. Phylogenetic analysis places the new form within or adjacent to crown Crocodylus. CONCLUSIONS/SIGNIFICANCE: The new crocodile species was the largest predator encountered by our ancestors at Olduvai Gorge, as indicated by hominid specimens preserving crocodile bite marks from these sites. The new species also reinforces the emerging view of high crocodylian diversity throughout the Neogene, and it represents one of the few extinct species referable to crown genus Crocodylus.

  4. Impacts of Climate Change and Human Activities on the Three Gorges Reservoir Inflow

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    Yu Zhang

    2017-12-01

    Full Text Available Identifying changes in runoff and quantifying the impacts of climate change and human activities are of great significance for water resources planning and management in a river basin. In this study, an inflow series of the Three Gorges Reservoir observed from 1951 to 2016 is used to identify the trend and abrupt change point by using statistical methods. Based on the meteorological data, soil type data, and land use data during the same period, the Soil and Water Assessment Tool (SWAT model is established to quantitatively attribute changes in the Three Gorges Reservoir inflow to climate change and human activities separately and discuss the differences between the two-stage method, which divides the whole study period into two stages to analyze the reasons for runoff evolution, and multi-stage method, which divides the whole study period into more stages to consider the temporal and spatial variation of land use/cover (LULC. The results show: (1 During the study period, a significant decrease is detected in the Three Gorges Reservoir inflow and the decrease rate is 7.7 km3 per ten years, annual total precipitation decreases by −13.5 mm per ten years, and annual average temperature increases by 0.1 °C per ten years. (2 Contribution of climate change and human activities is around 7:3. Climate change is the main reason for the decrease in the Three Gorges Reservoir inflow. (3 Results of stages in multi-stage method are different from the result of two-stage method. Accumulative results of multi-stage method and result of two-stage method are consistent. There are some changes in results of every stage, which are different from the accumulative results.

  5. [Effects of altitudes on soil microbial biomass and enzyme activity in alpine-gorge regions.

    Science.gov (United States)

    Cao, Rui; Wu, Fu Zhong; Yang, Wan Qin; Xu, Zhen Feng; Tani, Bo; Wang, Bin; Li, Jun; Chang, Chen Hui

    2016-04-22

    In order to understand the variations of soil microbial biomass and soil enzyme activities with the change of altitude, a field incubation was conducted in dry valley, ecotone between dry valley and mountain forest, subalpine coniferous forest, alpine forest and alpine meadow from 1563 m to 3994 m of altitude in the alpine-gorge region of western Sichuan. The microbial biomass carbon and nitrogen, and the activities of invertase, urease and acid phosphorus were measured in both soil organic layer and mineral soil layer. Both the soil microbial biomass and soil enzyme activities showed the similar tendency in soil organic layer. They increased from 2158 m to 3028 m, then decreased to the lowest value at 3593 m, and thereafter increased until 3994 m in the alpine-gorge region. In contrast, the soil microbial biomass and soil enzyme activities in mineral soil layer showed the trends as, the subalpine forest at 3028 m > alpine meadow at 3994 m > montane forest ecotone at 2158 m > alpine forest at 3593 m > dry valley at 1563 m. Regardless of altitudes, soil microbial biomass and soil enzyme activities were significantly higher in soil organic layer than in mineral soil layer. The soil microbial biomass was significantly positively correlated with the activities of the measured soil enzymes. Moreover, both the soil microbial biomass and soil enzyme activities were significantly positively correlated with soil water content, organic carbon, and total nitrogen. The activity of soil invertase was significantly positively correlated with soil phosphorus content, and the soil acid phosphatase was so with soil phosphorus content and soil temperature. In brief, changes in vegetation and other environmental factors resulting from altitude change might have strong effects on soil biochemical properties in the alpine-gorge region.

  6. Vegetation Activity Trend and Its Relationship with Climate Change in the Three Gorges Area, China

    Directory of Open Access Journals (Sweden)

    Guifeng Han

    2013-01-01

    Full Text Available Based on SPOT/VGT NDVI time series images from 1999 to 2009 in the Three Gorges Area (TGA, we detected vegetation activity and trends using two methods, the Mann-Kendall and Slope tests. The relationships between vegetation activity trends and annual average temperature and annual total precipitation were analyzed using observational data in seven typical meteorological stations. Vegetation activity presents a distinctive uptrend during the study period, especially in Fengjie, Yunyang, Wushan, Wuxi, and Badong counties located in the midstream of the Three Gorges Reservoir. However, in the Chongqing major area (CMA and its surrounding areas and Fuling, Yichang, and part of Wanzhou, vegetation activity shows a decreasing trend as a result of urban expansion. The NDVI has two fluctuation troughs in 2004 and 2006. The annual mean temperature presents a slight overall upward trend, but the annual total precipitation does not present a significant trend. And they almost have no significant correlations with the NDVI. Therefore, temperature and precipitation are not major influences on vegetation activity change. Instead, increasing vegetation cover benefits from a number of environment protection policies and management, and ecological construction is a major factor resulting in the upward trend. In addition, resettlement schemes mitigate the impact of human activity on vegetation activity.

  7. Chemical Characteristics of Precipitation in a Typical Urban Site of the Hinterland in Three Gorges Reservoir, China

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    Liuyi Zhang

    2018-01-01

    Full Text Available Major water-soluble ions were analyzed for two-year precipitation samples in Wanzhou, a typical urban site of the hinterland of Chinese Three Gorges Reservoir. The pH values of the precipitation were in the range of 4.0 to 8.3, and the volume-weighted mean (VWM value was 5.0. The concentration order of anions and cations was as follows: SO42->NO3->Cl->F- and NH4+>Ca2+>Na+>K+>Mg2+, respectively. Good correlations were found between SO42- and NH4+, SO42- and Ca2+, NO3- and NH4+, and NO3- and Ca2+, implying their co-occurrence in the precipitation, most likely as (NH42SO4, (NH4HSO4, NH4NO3, CaSO4, and Ca(NO32. The sum of all measured ions was 416.4 μeq L−1, indicating serious air pollution in Wanzhou. NH4+ and Ca2+ were the most important ions neutralizing the acidic compounds in the precipitation; their major sources included agricultural activity and crustal dust. Local anthropogenic activities, for example, coal burning and traffic related sources, contributed most of SO42- and NO3-. The equivalent concentration ratio of SO42-/NO3- was 4.5, indicating that excessive emission of sulfur was the main reason leading to the precipitation acidity in Wanzhou. However, this ratio was lower than the ratio (5.9 in 2000s in Wanzhou, indicating that the contribution of nitric acid to the acidity of precipitation was strengthening.

  8. Changes in Soil Enzyme Activities and Microbial Biomass after Revegetation in the Three Gorges Reservoir, China

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    Qingshui Ren

    2018-05-01

    Full Text Available Soil enzymes and microbes are central to the decomposition of plant and microbial detritus, and play important roles in carbon, nitrogen, and phosphorus biogeochemistry cycling at the ecosystem level. In the present study, we characterized the soil enzyme activity and microbial biomass in revegetated (with Taxodium distichum (L. Rich. and Cynodon dactylon (L. Pers. versus unplanted soil in the riparian zone of the Three Gorges Dam Reservoir (TGDR, in order to quantify the effect of revegetation on the edaphic microenvironment after water flooding in situ. After revegetation, the soil physical and chemical properties in revegetated soil showed significant differences to those in unplanted soil. The microbial biomass carbon and phosphorus in soils of T. distichum were significantly higher than those in C. dactylon and unplanted soils, respectively. The microbial biomass nitrogen in revegetated T. distichum and C. dactylon soils was significantly increased by 273% and 203%, respectively. The enzyme activities of T. distichum and C. dactylon soils displayed no significant difference between each other, but exhibited a great increase compared to those of the unplanted soil. Elements ratio (except C/N (S did not vary significantly between T. distichum and C. dactylon soils; meanwhile, a strong community-level elemental homeostasis in the revegetated soils was found. The correlation analyses demonstrated that only microbial biomass carbon and phosphorus had a significantly positive relationship with soil enzyme activities. After revegetation, both soil enzyme activities and microbial biomasses were relatively stable in the T. distichum and C. dactylon soils, with the wooded soil being more superior. The higher enzyme activities and microbial biomasses demonstrate the C, N, and P cycling and the maintenance of soil quality in the riparian zone of the TGDR.

  9. Causes of haze in the Columbia River Gorge

    Energy Technology Data Exchange (ETDEWEB)

    Mark Green; Jin Xu [Desert Research Institute, Reno, NV (United States)

    2007-08-15

    Visibility impairment in the Columbia River Gorge National Scenic Area is an area of concern. A field study conducted from July 2003 to February 2005 was followed by data analysis and receptor modeling to better understand the temporal and spatial patterns of haze and the sources contributing to the haze in the Columbia River Gorge in the states of Washington and Oregon. The nephelometer light scattering and surface meteorological data at eight sites along the gorge showed five distinct wind patterns, each with its characteristic diurnal and spatial patterns in light scattering by particles (b{sub sp}). In summer, winds were nearly always from west to east (upgorge) and showed decreasing b{sub sp} with distance into the gorge and a pronounced effect of the Portland, OR, metropolitan area on haze, especially in the western portions of the gorge. Winter often had winds from the east with very high levels of b{sub sp}, especially at the eastern gorge sites, with sources east of the gorge responsible for much of the haze. The major chemical components responsible for haze were organic carbon, sulfate, and nitrate. Positive matrix factorization (PMF) using chemically speciated Interagency Monitoring of Protected Visual Environments data indicated seven source factors in the western gorge and five factors in the eastern gorge. Organic mass is a large contributor to haze in the gorge in all seasons, with a peak in fall. Approximately half of the organic mass is biomass smoke, with mobile sources as the second largest contributor. PMF analysis showed nitrates mainly attributed to a generic secondary nitrate factor. Sulfate is a significant contributor in all seasons, with peak sulfate concentrations in summer. Sources east of the gorge, likely a coal-fired power plant, nearby dairy farm, and upriver cities, appear to be major contributors to wintertime haze in the gorge. 22 refs., 11 figs., 6 tabs.

  10. Unraveling hominin behavior at another anthropogenic site from Olduvai Gorge (Tanzania): new archaeological and taphonomic research at BK, Upper Bed II.

    Science.gov (United States)

    Domínguez-Rodrigo, M; Mabulla, A; Bunn, H T; Barba, R; Diez-Martín, F; Egeland, C P; Espílez, E; Egeland, A; Yravedra, J; Sánchez, P

    2009-09-01

    New archaeological excavations and research at BK, Upper Bed II (Olduvai Gorge, Tanzania) have yielded a rich and unbiased collection of fossil bones. These new excavations show that BK is a stratified deposit formed in a riverine setting close to an alluvial plain. The present taphonomic study reveals the second-largest collection of hominin-modified bones from Olduvai, with abundant cut marks found on most of the anatomical areas preserved. Meat and marrow exploitation is reconstructed using the taphonomic signatures left on the bones by hominins. Highly cut-marked long limb shafts, especially those of upper limb bones, suggest that hominins at BK were actively engaged in acquiring small and middle-sized animals using strategies other than passive scavenging. The exploitation of large-sized game (Pelorovis) by Lower Pleistocene hominins, as suggested by previous researchers, is supported by the present study.

  11. Cultural considerations at Three Gorges

    Energy Technology Data Exchange (ETDEWEB)

    Wang Rushu [China TGP Development Corporation, Hunbei (China)

    2000-08-01

    More than 100 interesting relics and sites will be affected when the Yangtze Three Gorges dam is impounded in one of the most important historical regions of China. This great tourist attraction has survived for 5000 years. The Chinese government is fully cognisant of the need to protect its inheritance and appropriate plans have been formulated in advance of the lake (surface area 1084 km{sup 2}) which will be formed. The article discusses protection measures, policies and laws for cultural protection, and the fate of relics found. The types of relics in the area are listed and a summary of the project programme is given. The plans are in place to build a first class hydro scheme whilst protecting the environment and protecting cultural relics and heritage.

  12. Three Gorges news: power struggle

    Energy Technology Data Exchange (ETDEWEB)

    Fennell, T.; Mooney, P.

    1999-08-16

    Inside Beijing's Zhongnanhai Compound, where the top leaders in China work, the Three Gorges power project is known as Canada's dam, because Canadian taxpayers funded the study that led to the creation of the $45 billion hydroelectric dam on the Yangtze River, the largest ever conceived. When completed in 2009, the village homes and town apartments of almost 1.5 million people will be submerged beneath a lake reservoir longer than Lake Superior. For them the dreams of Canadian engineers will have become a nightmare. As the River rises, thousands will be forcibly removed, but mounting problems could slow the process. The relocation drive is behind, construction is running over cost, and top officials are criticizing the project. All of this has led its opponents to hope that plans for Canada's dam may be altered before it becomes China's disaster. Senior staff at Canada's embassy met recently with Chinese officials to discuss the dam's troubled financing, and were told that the project was under control. When visiting the vast construction site, which is the size of a small city, it is difficult to imagine that Three Gorges could be halted. Nearly 25,000 workers, working around the clock, have already completed the foundation of the 185 m high dam. Once complete, its 126 turbines, three of which are being built by GE Canada, will match the output of 18 nuclear power plants. The two km wide barrier will also provide critical flood control along the Yangtze River. The negative socio-environmental impacts are stressed. 2 maps.

  13. Three Gorges news: power struggle

    International Nuclear Information System (INIS)

    Fennell, T.; Mooney, P.

    1999-01-01

    Inside Beijing's Zhongnanhai Compound, where the top leaders in China work, the Three Gorges power project is known as Canada's dam, because Canadian taxpayers funded the study that led to the creation of the $45 billion hydroelectric dam on the Yangtze River, the largest ever conceived. When completed in 2009, the village homes and town apartments of almost 1.5 million people will be submerged beneath a lake reservoir longer than Lake Superior. For them the dreams of Canadian engineers will have become a nightmare. As the River rises, thousands will be forcibly removed, but mounting problems could slow the process. The relocation drive is behind, construction is running over cost, and top officials are criticizing the project. All of this has led its opponents to hope that plans for Canada's dam may be altered before it becomes China's disaster. Senior staff at Canada's embassy met recently with Chinese officials to discuss the dam's troubled financing, and were told that the project was under control. When visiting the vast construction site, which is the size of a small city, it is difficult to imagine that Three Gorges could be halted. Nearly 25,000 workers, working around the clock, have already completed the foundation of the 185 m high dam. Once complete, its 126 turbines, three of which are being built by GE Canada, will match the output of 18 nuclear power plants. The two km wide barrier will also provide critical flood control along the Yangtze River. The negative socio-environmental impacts are stressed. 2 maps

  14. Unmasking tandem site interaction in human acetylcholinesterase. Substrate activation with a cationic acetanilide substrate.

    Science.gov (United States)

    Johnson, Joseph L; Cusack, Bernadette; Davies, Matthew P; Fauq, Abdul; Rosenberry, Terrone L

    2003-05-13

    Acetylcholinesterase (AChE) contains a narrow and deep active site gorge with two sites of ligand binding, an acylation site (or A-site) at the base of the gorge, and a peripheral site (or P-site) near the gorge entrance. The P-site contributes to catalytic efficiency by transiently binding substrates on their way to the acylation site, where a short-lived acyl enzyme intermediate is produced. A conformational interaction between the A- and P-sites has recently been found to modulate ligand affinities. We now demonstrate that this interaction is of functional importance by showing that the acetylation rate constant of a substrate bound to the A-site is increased by a factor a when a second molecule of substrate binds to the P-site. This demonstration became feasible through the introduction of a new acetanilide substrate analogue of acetylcholine, 3-(acetamido)-N,N,N-trimethylanilinium (ATMA), for which a = 4. This substrate has a low acetylation rate constant and equilibrates with the catalytic site, allowing a tractable algebraic solution to the rate equation for substrate hydrolysis. ATMA affinities for the A- and P-sites deduced from the kinetic analysis were confirmed by fluorescence titration with thioflavin T as a reporter ligand. Values of a >1 give rise to a hydrolysis profile called substrate activation, and the AChE site-specific mutant W86F, and to a lesser extent wild-type human AChE itself, showed substrate activation with acetylthiocholine as the substrate. Substrate activation was incorporated into a previous catalytic scheme for AChE in which a bound P-site ligand can also block product dissociation from the A-site, and two additional features of the AChE catalytic pathway were revealed. First, the ability of a bound P-site ligand to increase the substrate acetylation rate constant varied with the structure of the ligand: thioflavin T accelerated ATMA acetylation by a factor a(2) of 1.3, while propidium failed to accelerate. Second, catalytic rate

  15. [Effects of Citric Acid on Activation and Methylation of Mercury in the Soils of Water-Level-Fluctuating Zone of the Three Gorges.Reservoir].

    Science.gov (United States)

    Qin, Cai-qing; Liang, Li; You, Rui; Deng, Han; Wang, Ding-yong

    2015-12-01

    To investigate effects of the main component of vegetation root exudates-citric acid on activation and methylation of mercury in the soil of water-level-fluctuating zone (WLFZ) of the Three Gorges Reservoir area, simulation experiments were conducted by extracting and cultivating soil with different concentrations of citric acid. The results showed that after adding citric acid, the total mercury content in leaching solution before reaching peak were higher than that of the control, and increased with the increase of citric acid concentrations. The maximum amount of mercury complexes increased initially and then reached plateaus with the percentage against the total mercury in soil of 1.03%, 1.67%, 1.99%, 2.47%, 2.68%, 2.73% and 2.73% for different citric acid concentrations (0, 1, 2, 4, 5, 6 and 8 mmol · L⁻¹). In addition, concentrations of methylmercury ( MeHg) in soil remained stable in the first 3 hours, and then increased accompanying with the increasing rate rising with the concentration of citric acid ( besides the control group) . This result indicated that citric acid probably could promote the transformation process from inorganic mercury to MeHg in soil. which increased with the concentration of citric acid.

  16. Rare birds of prey observations in Kresna Gorge in Bulgaria

    African Journals Online (AJOL)

    Campbell Murn

    the feeding site and roost in the area in 2013. Passage of birds from Serbia,. Croatia, FYR of Macedonia and. Greece were recorded, as well as a bird tagged in Israel, but most were probably of Balkan origin. There are two peaks of increased presence of exogenous Griffon Vultures in. Kresna Gorge and these are in May-.

  17. NDVI indicated long-term interannual changes in vegetation activities and their responses to climatic and anthropogenic factors in the Three Gorges Reservoir Region, China.

    Science.gov (United States)

    Wen, Zhaofei; Wu, Shengjun; Chen, Jilong; Lü, Mingquan

    2017-01-01

    Natural and social environmental changes in the China's Three Gorges Reservoir Region (TGRR) have received worldwide attention. Identifying interannual changes in vegetation activities in the TGRR is an important task for assessing the impact these changes have on the local ecosystem. We used long-term (1982-2011) satellite-derived Normalized Difference Vegetation Index (NDVI) datasets and climatic and anthropogenic factors to analyze the spatiotemporal patterns of vegetation activities in the TGRR, as well as their links to changes in temperature (TEM), precipitation (PRE), downward radiation (RAD), and anthropogenic activities. At the whole TGRR regional scale, a statistically significant overall uptrend in NDVI variations was observed in 1982-2011. More specifically, there were two distinct periods with different trends split by a breakpoint in 1991: NDVI first sharply increased prior to 1991, and then showed a relatively weak rate of increase after 1991. At the pixel scale, most parts of the TGRR experienced increasing NDVI before the 1990s but different trend change types after the 1990s: trends were positive in forests in the northeastern parts, but negative in farmland in southwest parts of the TGRR. The TEM warming trend was the main climate-related driver of uptrending NDVI variations pre-1990s, and decreasing PRE was the main climate factor (42%) influencing the mid-western farmland areas' NDVI variations post-1990s. We also found that anthropogenic factors such as population density, man-made ecological restoration, and urbanization have notable impacts on the TGRR's NDVI variations. For example, large overall trend slopes in NDVI were more likely to appear in TGRR regions with large fractions of ecological restoration within the last two decades. The findings of this study may help to build a better understanding of the mechanics of NDVI variations in the periods before and during TGDP construction for ongoing ecosystem monitoring and assessment in the

  18. Aryl hydrocarbon receptor (AhR) inducers and estrogen receptor (ER) activities in surface sediments of Three Gorges Reservoir, China evaluated with in vitro cell bioassays

    NARCIS (Netherlands)

    Wang, J.; Bovee, T.F.H.; Bi, Y.; Bernhöft, S.; Schramm, K.W.

    2014-01-01

    Two types of biological tests were employed for monitoring the toxicological profile of sediment cores in the Three Gorges Reservoir (TGR), China. In the present study, sediments collected in June 2010 from TGR were analyzed for estrogen receptor (ER)- and aryl hydrocarbon receptor (AhR)-mediated

  19. DOE site performance assessment activities

    International Nuclear Information System (INIS)

    1990-07-01

    Information on performance assessment capabilities and activities was collected from eight DOE sites. All eight sites either currently dispose of low-level radioactive waste (LLW) or plan to dispose of LLW in the near future. A survey questionnaire was developed and sent to key individuals involved in DOE Order 5820.2A performance assessment activities at each site. The sites surveyed included: Hanford Site (Hanford), Idaho National Engineering Laboratory (INEL), Los Alamos National Laboratory (LANL), Nevada Test Site (NTS), Oak Ridge National Laboratory (ORNL), Paducah Gaseous Diffusion Plant (Paducah), Portsmouth Gaseous Diffusion Plant (Portsmouth), and Savannah River Site (SRS). The questionnaire addressed all aspects of the performance assessment process; from waste source term to dose conversion factors. This report presents the information developed from the site questionnaire and provides a comparison of site-specific performance assessment approaches, data needs, and ongoing and planned activities. All sites are engaged in completing the radioactive waste disposal facility performance assessment required by DOE Order 5820.2A. Each site has achieved various degrees of progress and have identified a set of critical needs. Within several areas, however, the sites identified common needs and questions

  20. How does huperzine A enter and leave the binding gorge of acetylcholinesterase? Steered molecular dynamics simulations.

    Science.gov (United States)

    Xu, Yechun; Shen, Jianhua; Luo, Xiaomin; Silman, Israel; Sussman, Joel L; Chen, Kaixian; Jiang, Hualiang

    2003-09-17

    The entering and leaving processes of Huperzine A (HupA) binding with the long active-site gorge of Torpedo californica acetylcholinesterase (TcAChE) have been investigated by using steered molecular dynamics simulations. The analysis of the force required along the pathway shows that it is easier for HupA to bind to the active site of AChE than to disassociate from it, which for the first time interprets at the atomic level the previous experimental result that unbinding process of HupA is much slower than its binding process to AChE. The direct hydrogen bonds, water bridges, and hydrophobic interactions were analyzed during two steered molecular dynamics (SMD) simulations. Break of the direct hydrogen bond needs a great pulling force. The steric hindrance of bottleneck might be the most important factor to produce the maximal rupture force for HupA to leave the binding site but it has a little effect on the binding process of HupA with AChE. Residue Asp72 forms a lot of water bridges with HupA leaving and entering the AChE binding gorge, acting as a clamp to take out HupA from or put HupA into the active site. The flip of the peptide bond between Gly117 and Gly118 has been detected during both the conventional MD and SMD simulations. The simulation results indicate that this flip phenomenon could be an intrinsic property of AChE and the Gly117-Gly118 peptide bond in both HupA bound and unbound AChE structures tends to adopt the native enzyme structure. At last, in a vacuum the rupture force is increased up to 1500 pN while in water solution the greatest rupture force is about 800 pN, which means water molecules in the binding gorge act as lubricant to facilitate HupA entering or leaving the binding gorge.

  1. Occurrence, fate and ecotoxicological assessment of pharmaceutically active compounds in wastewater and sludge from wastewater treatment plants in Chongqing, the Three Gorges Reservoir Area

    International Nuclear Information System (INIS)

    Yan, Qing; Gao, Xu; Chen, You-Peng; Peng, Xu-Ya; Zhang, Yi-Xin; Gan, Xiu-Mei; Zi, Cheng-Fang; Guo, Jin-Song

    2014-01-01

    The occurrence, removal and ecotoxicological assessment of 21 pharmaceutically active compounds (PhACs) including antibiotics, analgesics, antiepileptics, antilipidemics and antihypersensitives, were studied at four municipal wastewater treatment plants (WWTP) in Chongqing, the Three Gorges Reservoir Area. Individual treatment unit effluents, as well as primary and secondary sludge, were sampled and analyzed for the selected PhACs to evaluate their biodegradation, persistence and partitioning behaviors. PhACs were identified and quantified using high performance liquid chromatography/tandem mass spectrometry after solid-phase extraction. All the 21 analyzed PhACs were detected in wastewater and the target PhACs except acetaminophen, ibuprofen and gemfibrozil, were also found in sludge. The concentrations of the antibiotics and SVT were comparable to or even higher than those reported in developed countries, while the case of other target PhACs was opposite. The elimination of PhACs except acetaminophen was incomplete and a wide range of elimination efficiencies during the treatment were observed, i.e. from “negative removal” to 99.5%. The removal of PhACs was insignificant in primary and disinfection processes, and was mainly achieved during the biological treatment. Based on the mass balance analysis, biodegradation is believed to be the primary removal mechanism, whereas only about 1.5% of the total mass load of the target PhACs was removed by sorption. Experimentally estimated distribution coefficients ( 2 O) in effluent and sludge, as well as the mixture of the 21 detected PhACs in effluent, sludge and receiving water had a significant ecotoxicological risk to algae. Therefore, further control of PhACs in effluent and sludge is required before their discharge and application to prevent their introduction into the environment. - Highlights: • All the 21 analyzed PhACs were detected in wastewater and 18 in sludge. • The removal of PhACs was insignificant

  2. Occurrence, fate and ecotoxicological assessment of pharmaceutically active compounds in wastewater and sludge from wastewater treatment plants in Chongqing, the Three Gorges Reservoir Area

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Qing, E-mail: qyan2005@hotmail.com [Key Laboratory of the Three Gorges Reservoir Region' s Eco-Environments of Ministry of Education, Chongqing University, Chongqing 400045 (China); College of Geography Science and Tourism, Chongqing Normal University, Chongqing 400047 (China); Gao, Xu, E-mail: gaoxu@cqu.edu.cn [Key Laboratory of the Three Gorges Reservoir Region' s Eco-Environments of Ministry of Education, Chongqing University, Chongqing 400045 (China); Chen, You-Peng [Key Laboratory of the Three Gorges Reservoir Region' s Eco-Environments of Ministry of Education, Chongqing University, Chongqing 400045 (China); Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122 (China); Peng, Xu-Ya; Zhang, Yi-Xin; Gan, Xiu-Mei; Zi, Cheng-Fang [Key Laboratory of the Three Gorges Reservoir Region' s Eco-Environments of Ministry of Education, Chongqing University, Chongqing 400045 (China); Guo, Jin-Song [Key Laboratory of the Three Gorges Reservoir Region' s Eco-Environments of Ministry of Education, Chongqing University, Chongqing 400045 (China); Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122 (China)

    2014-02-01

    The occurrence, removal and ecotoxicological assessment of 21 pharmaceutically active compounds (PhACs) including antibiotics, analgesics, antiepileptics, antilipidemics and antihypersensitives, were studied at four municipal wastewater treatment plants (WWTP) in Chongqing, the Three Gorges Reservoir Area. Individual treatment unit effluents, as well as primary and secondary sludge, were sampled and analyzed for the selected PhACs to evaluate their biodegradation, persistence and partitioning behaviors. PhACs were identified and quantified using high performance liquid chromatography/tandem mass spectrometry after solid-phase extraction. All the 21 analyzed PhACs were detected in wastewater and the target PhACs except acetaminophen, ibuprofen and gemfibrozil, were also found in sludge. The concentrations of the antibiotics and SVT were comparable to or even higher than those reported in developed countries, while the case of other target PhACs was opposite. The elimination of PhACs except acetaminophen was incomplete and a wide range of elimination efficiencies during the treatment were observed, i.e. from “negative removal” to 99.5%. The removal of PhACs was insignificant in primary and disinfection processes, and was mainly achieved during the biological treatment. Based on the mass balance analysis, biodegradation is believed to be the primary removal mechanism, whereas only about 1.5% of the total mass load of the target PhACs was removed by sorption. Experimentally estimated distribution coefficients (< 500 L/kg, with a few exceptions) also indicate that biodegradation/transformation was responsible for the removal of the target PhACs. Ecotoxicological assessment indicated that the environment concentrations of single compounds (including sulfadiazine, sulfamethoxazole, ofloxacin, azithromycin and erythromycin-H{sub 2}O) in effluent and sludge, as well as the mixture of the 21 detected PhACs in effluent, sludge and receiving water had a significant

  3. Salt site performance assessment activities

    International Nuclear Information System (INIS)

    Kircher, J.F.; Gupta, S.K.

    1983-01-01

    During this year the first selection of the tools (codes) for performance assessments of potential salt sites have been tentatively selected and documented; the emphasis has shifted from code development to applications. During this period prior to detailed characterization of a salt site, the focus is on bounding calculations, sensitivity and with the data available. The development and application of improved methods for sensitivity and uncertainty analysis is a focus for the coming years activities and the subject of a following paper in these proceedings. Although the assessments to date are preliminary and based on admittedly scant data, the results indicate that suitable salt sites can be identified and repository subsystems designed which will meet the established criteria for protecting the health and safety of the public. 36 references, 5 figures, 2 tables

  4. Geomorphological evolution of a fluvial channel after primary lahar deposition: Huiloac Gorge, Popocatépetl volcano (Mexico)

    Science.gov (United States)

    Tanarro, L. M.; Andrés, N.; Zamorano, J. J.; Palacios, D.; Renschler, C. S.

    2010-10-01

    Popocatépetl volcano (19°02' N, 98°62' W, 5424 m) began its most recent period of volcanic activity in December 1994. The interaction of volcanic and glacier activity triggered the formation of lahars through the Huiloac Gorge, located on the northern flank of the volcano, causing significant morphological changes in the channel. The most powerful lahars occurred in April 1995, July 1997 and January 2001, and were followed by secondary lahars that formed during the post-eruptive period. This study interprets the geomorphological evolution of the Huiloac Gorge after the January 2001 lahar. Variations in channel morphology at a 520 m-long research site located mid-way down the gorge were recorded over a 4 year period from February 2002 to March 2005, and depicted in five geomorphological maps (scale 1:200) for 14 February and 15 October 2002, 27 September 2003, 9 February 2004, and 16 March 2006. A GIS was used to calculate the surface area for the landforms identified for each map and detected changes and erosion-deposition processes of the landforms using the overlay function for different dates. Findings reveal that secondary lahars and others types of flows, like sediment-laden or muddy streamflows caused by precipitation, rapidly modified the gorge channel following the January 2001 non-eruptive lahar, a period associated with volcanic inactivity and the disappearance of the glacier once located at the headwall of the gorge. Field observations also confirmed that secondary flows altered the dynamics and geomorphological development of the channel. These flows incised and destroyed the formations generated by the primary lahars (1997 and 2001), causing a widening of the channel that continues today. After February 2004, a rain-triggered lahar and other flows infilled the channel with materials transported by these flows. The deposits on the lateral edges of the channel form terraces. A recent lull in lahar activity contrasts with the increasing instability of

  5. Erosion of the Yarlung-Tsangpo Gorge sustained by episodic megaflooding

    Science.gov (United States)

    Lang, K. A.; Huntington, K. W.

    2012-12-01

    As the Yarlung-Tsangpo river descends through the easternmost Himalaya to join the Brahmaputra river in India, it carves a ~2 km-deep knickzone: the Yarlung-Tsangpo Gorge. Within the gorge, fluvial incision has kept pace with an active crustal scale antiform, exhuming mid-crustal material over Pliocene time at rates up to 7-10 km/Myr. This close spatial correspondence of erosion and exhumation has led previous researchers to hypothesize a self-perpetuating relationship between focused erosion and rock uplift in this ~1200 km^2 region. While high discharge in the river today produces bed stresses that may have the erosional capability to match rock uplift rates, this hypothesis also requires erosion to be localized in the gorge region over timescales spanning multiple glacial periods during which the upstream drainage was episodically dammed by glaciers and discharge was variable. We interpret downstream flood deposits corresponding to this episodic damming as direct evidence of megaflood action as the principal agent of gorge erosion, spanning multiple glacial periods and potentially matching the million-year exhumation rates independently measured in the gorge. Previous researchers documented evidence of glacial damming throughout the fluvial network upstream of the gorge, where moraine and landslide dams are abundant, often beneath dissected lake deposits. We report flood deposits downstream of the gorge, remaining along valley walls at multiple elevations up to 150 m off the modern channel. Using LA-ICPMS U-Pb dating of detrital zircons from these flood sediments, we demonstrate that these high-magnitude flood events disproportionately excavated material from the Yarlung-Tsangpo Gorge, and propose an alternative erosional mechanism to match rock uplift in the gorge over a 10^6 year timescale. We analyzed five flood deposits spanning a range of elevations above the modern channel and four deposits from a documented lower-magnitude flood in 2000. We constrain

  6. A reassessment of the study of cut mark patterns to infer hominid manipulation of fleshed carcasses at the Flk Zinj 22 site, Olduvai Gorge, Tanzania

    Directory of Open Access Journals (Sweden)

    Domínguez-Rodrigo, Manuel

    1997-12-01

    Full Text Available Previous experimental studies on cut marks have suggested that cut mark percentages and their anatomical distribution (based on element type and bone section type could be used to differentiate primary access to fleshed carcasses from secondary access to defleshed carcasses. In this study, the experimental sample of this type of studies is increased and further data are included to infer a primary access by hominids to carcasses at the FLK Zinj site of Olduvai.

    Estudios experimentales anteriores sobre marcas de corte han sugerido que los porcentajes de marcas de corte y su distribución (basada en tipo de hueso y tipo de sección ósea podrían usarse para diferenciar un acceso primario a carcasas con carne de un acceso secundario a carcasas descarnadas. En este estudio semejante muestra experimental se ve ampliada y se muestran más datos que sirven para inferir que los homínidos tuvieron un acceso primario a las carcasas representadas en el yacimiento FLK Zinj de Olduvai.

  7. MARKETING RESEARCH REGARDING TOURISM BUSINESS READINESS FOR ECO-LABEL ACHIEVEMENT (CASE STUDY: NATURA 2000 CRIŞUL REPEDE GORGE-PĂDUREA CRAIULUI PASS SITE, ROMANIA

    Directory of Open Access Journals (Sweden)

    Olimpia Iuliana BAN

    2015-12-01

    Full Text Available Sustainable development is an approach that aims to preserve the environment and the culture of communities hosting tourists and at the same time to meet the needs of tourists and to maintain the growth of tourism industry. These objectives are more and more related to eco-labelling, which provides the certification based on a series of benchmarks developed and verified by a third party. The labelling of an organization as an ecotourism organization requires the compliance with certain criteria as those required by the European Ecotourism Labelling Standard. Natura 2000 Crişul Repede Gorge– Pădurea Craiului Pass site will have to prove that it is in compliance with the prerequisites to become an ecotourism destination. The objectives of this paper are: to identify the prerequisites that a destination must comply with in order to be labelled an ecotourism destination, focusing on the prerequisites related to the existence and behaviour of tourist reception structures; to identify the extent to which tour operators are open  and willing to support the labelling of the destination where they operate as being ecotourism.  

  8. Spatial and temporal patterns of greenhouse gas emissions from Three Gorges Reservoir of China

    Directory of Open Access Journals (Sweden)

    Y. Zhao

    2013-02-01

    Full Text Available Anthropogenic activity has led to significant emissions of greenhouse gas (GHG, which is thought to play important roles in global climate changes. It remains unclear about the kinetics of GHG emissions, including carbon dioxide (CO2, methane (CH4 and nitrous Oxide (N2O from the Three Gorges Reservoir (TGR of China, which was formed after the construction of the famous Three Gorges Dam. Here we report monthly measurements for one year of the fluxes of these gases at multiple sites within the TGR region, including three major tributaries, six mainstream sites, two downstream sites and one upstream site. The tributary areas have lower CO2 fluxes than the main storage; CH4 fluxes in the tributaries and upper reach mainstream sites are relative higher. Overall, TGR showed significantly lower CH4 emission rates than most new reservoirs in temperate and tropical regions. We attribute this to the well-oxygenated deep water and high water velocities that may facilitate the consumption of CH4. TGR's CO2 fluxes were lower than most tropical reservoirs and higher than most temperate systems. This could be explained by the high load of labile soil carbon delivered through erosion to the Yangtze River. Compared to fossil-fuelled power plants of equivalent power output, TGR is a very small GHG emitter – annual CO2-equivalent emissions are approximately 1.7% of that of a coal-fired generating plant of comparable power output.

  9. Dating the Naisiusiu Beds, Olduvai Gorge, by electron spin resonance

    Science.gov (United States)

    Skinner, A. R.; Hay, R. L.; Masao, F.; Blackwell, B. A. B.

    2003-05-01

    The lower beds at Olduvai Gorge are well known for containing early hominid fossils and Oldowan stone tools, and their ages have been established by 40Ar/ 39Ar dating and paleomagnetic stratigraphy. Ages are generally less certain for the upper deposits at Olduvai Gorge because of the scarcity of datable tuffs. The youngest archaeologically significant site at Olduvai is microlithic LSA, which lies in the type section of the Naisiusiu Beds. The age for the site is controversial, with 14C dates of 17,000-17,550 (Hay, R.L., 1976 Geology of Olduvai Gorge, University of California Press, Berkeley) and >42,000 BP (Manega, P.C., 1993. Geochronology, geochemistry, and isotopic study of the Plio-Pleistocene Hominid sites and the Ngorongoro Volcanic Highland in Northern Tanzania. Unpublished Ph.D. Thesis, University of Colorado, Boulder, CO). The tuff bed in the zone with artifacts does not contain materials datable by 40Ar/ 39Ar, and some other dating method was needed. In the summer of 2001, five equid teeth were collected from the type Naisiusiu site. Another tooth had previously been collected. ESR ages have been determined for three teeth from the archaeological level and their ages cluster around 62±5 ka, assuming linear uranium uptake. Another tooth from a level without artifacts and believed to be significantly younger dated to 39±5 ka, again assuming LU. These dates are considerably older than previous estimates and suggest that the East African MSA/LSA transition occurred very early.

  10. On-site and off-site activities

    International Nuclear Information System (INIS)

    Martin, H.D.

    1986-01-01

    Design principles for NPP training programs. Effects of NPP contracts. Effects of domestic industrial activities. The role of international bodies. Requirements for on-site training. Training abroad, technical, financial and social aspects. Training center on-site, an evaluation. (orig.)

  11. GEOMORPHOLOGY. Comment on "Tectonic control of Yarlung Tsangpo Gorge revealed by a buried canyon in Southern Tibet".

    Science.gov (United States)

    Zeitler, Peter K; Koons, Peter O; Hallet, Bernard; Meltzer, Anne S

    2015-08-21

    Wang et al. (Reports, 21 November, 2014, p. 978) describe a buried canyon upstream of the Yarlung Tsangpo Gorge and argue that rapid erosion of the gorge was merely a passive response to rapid uplift at ~2.5 million years ago (Ma). We view these data as an expected consequence emerging from feedbacks between erosion and crustal rheology active well before 2.5 Ma. Copyright © 2015, American Association for the Advancement of Science.

  12. Active Site Engineering in Electrocatalysis

    DEFF Research Database (Denmark)

    Verdaguer Casadevall, Arnau; Stephens, Ifan; Chorkendorff, Ib

    on nanostructured electrodes.• Oxygen reduction to water has been carried out on Pt-rare earth alloys, which outperformed the activity of Pt by as much as a factor of five while showing promising stability. The increase in activity can be attributed to compressive strain of the Pt overlayer formed under reaction......, which greatly enhanced selectivity to H2O2 during oxygen reduction. Compared to state-of-theart Au-based catalysts, Pt-Hg and Pd-Hg alloys present over 20 and 100 times increase in mass activity respectively. It was proven that activity for this reaction is controlled by the binding energy of the sole...... reaction intermediate. • CO2 and CO electroreduction studies have attempted to understand the unprecedented activity of oxide-derived Cu recently reported in the literature. Temperature programmed desorption measurements reveal very strong CO binding at these surfaces, inexistent in other forms of Cu...

  13. Effects of hydropower operations on recreational use and nonuse values at Glen Canyon and Flaming Gorge Dams

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, J.L.

    1995-03-01

    Increases in streamflows are generally positively related to the use values of angling and white-water boating, and constant flows tend to increase the use values more than fluctuating flows. In most instances, however, increases in streamflows beyond some threshold level cause the use values to decrease. Expenditures related to angling and white-water boating account for about $24 million of activity in the local economy around Glen Canyon Dam and $24.8 million in the local economy around flaming Gorge Dam. The range of operational scenarios being considered in the Western Area Power Administration`s Electric Power Marketing Environmental Impact Statement, when use rates are held constant, could change the combined use value of angling and white-water boating below Glen Canyon Dam, increasing it by as much as 50%, depending on prevailing hydrological conditions. Changes in the combined use value below Flaming Gorge Dam could range from a decrease of 9% to an increase of 26%. Nonuse values, such as existence and bequest values, could also make a significant contribution to the total value of each site included in this study; however, methodological and data limitations prevented estimating how each operational scenario could change nonuse values.

  14. Raptor Use of the Rio Grande Gorge

    Energy Technology Data Exchange (ETDEWEB)

    Ponton, David A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-20

    The Rio Grande Gorge is a 115 km long river canyon located in Southern Colorado (15 km) and Northern New Mexico (100 km). The majority of the canyon is under the administration of the Bureau of Land Management {BLM), and 77 km of the canyon south of the Colorado/New Mexico border are designated Wild River under the National Wild and Scenic Rivers Act of 1968. Visits I have made to the Rio Grande Gorge over the past 15 .years disclosed some raptor utilization. As the Snake River Birds of Prey Natural Area gained publicity, its similarity to the Rio Grande Gorge became obvious, and I was intrigued by the possibility of a high raptor nesting density in the Gorge. A survey in 1979 of 20 km of the northern end of the canyon revealed a moderately high density of red-tailed hawks and prairie falcons. With the encouragement of that partial survey, and a need to assess the impact of river-running on nesting birds of prey, I made a more comprehensive survey in 1980. The results of my surveys, along with those of a 1978 helicopter survey by the BLM, are presented in this report, as well as general characterization of the area, winter use by raptors, and an assessment of factors influencing the raptor population.

  15. Efficient oxygen electrocatalysis on special active sites

    DEFF Research Database (Denmark)

    Halck, Niels Bendtsen

    throughout this thesis to understand these local structure effects and their influence on surface reactions. The concept of these special active sites is used to explain how oxygen evolution reaction (OER) catalysts can have activities beyond the limits of what was previously thought possible. The concept...... stored in these bonds in an eco-friendly fashion in fuel cells. This thesis explores catalysts for oxygen electrocatalysis and how carefully designed local structures on catalysts surfaces termed special active sites can influence the activity. Density functional theory has been used as a method...... is used to explain the increase in activity observed for the OER catalyst ruthenium dioxide when it is mixed with nickel or cobalt. Manganese and cobalt oxides when in the vicinity of gold also display an increase in OER activity which can be explained by locally created special active sites. Density...

  16. The hydraulic turbines of the Three Gorges dam; Les turbines hydrauliques du barrage des trois gorges

    Energy Technology Data Exchange (ETDEWEB)

    Bremond, J. [Societe GEC-Alsthom Neyrpic (France); Vuillerod, G. [Alsthom Hydro (France)

    1999-10-01

    As part of the hydroelectric installation of the Three Gorges on the Yangtze river in China, the Alsthom group recorded a major order for the supply of 8 Francis turbines out of the 14 to be installed in the left bank power station. This colossal project will include 26 Francis turbines of 710 MW, a spillway designed for a maximum flow of 116 000 m{sup 3}/s, a ship-lock of 5 steps with a capacity of 10 000 tons and a ship-lift of 3000 tons. The concrete gravity dam will be 2.3 km long. As oriented by the Specifications, and due to their exceptional size (runner diameter: 9800 mm), the design of these units relies upon well-proofed solutions such as those already experienced on the Itaipu south American large scale hydro project, in which Alsthom already contributed 20 years ago. The runners (450 tons each, external diameter 10 600 mm) will be fabricated by welding of separate elements made of martensitic stainless steel. Most of the components have to be delivered in several parts and reassembled at site by welding or bolting. The left bank power station is scheduled to be operational in 2006. (authors) 2 refs.

  17. Promoter proximal polyadenylation sites reduce transcription activity

    DEFF Research Database (Denmark)

    Andersen, Pia Kjølhede; Lykke-Andersen, Søren; Jensen, Torben Heick

    2012-01-01

    Gene expression relies on the functional communication between mRNA processing and transcription. We previously described the negative impact of a point-mutated splice donor (SD) site on transcription. Here we demonstrate that this mutation activates an upstream cryptic polyadenylation (CpA) site......, which in turn causes reduced transcription. Functional depletion of U1 snRNP in the context of the wild-type SD triggers the same CpA event accompanied by decreased RNA levels. Thus, in accordance with recent findings, U1 snRNP can shield premature pA sites. The negative impact of unshielded pA sites...... on transcription requires promoter proximity, as demonstrated using artificial constructs and supported by a genome-wide data set. Importantly, transcription down-regulation can be recapitulated in a gene context devoid of splice sites by placing a functional bona fide pA site/transcription terminator within ∼500...

  18. The world's biggest dam construction project at the Yangtze river. The Three Gorges project; Weltweit groesster Staudamm entsteht am Jangtse. Three-Gorges-Projekt

    Energy Technology Data Exchange (ETDEWEB)

    Kreher, G.

    2002-02-11

    The author, having seen the Three Gorges Project model exhibited at the Expo 2000 in Hannover, went there to get an impression of the real dimensions of this gigantic project. His report also contains personal impressions but primarily gives a picture of the engineering, landscaping, and social aspects and implications, also referring to relevant technical information obtained on site.(orig./CB) [German] Der Autor hat den Stand der Arbeiten am Three-Gorges-Projekt (TGP) anhand eines im China-Pavillon auf der Expo 2000 in Hannover detailliert vorgestellten Planungsprojektes zum Anlass genommen, sich vor Ort vom Fortgang der Arbeiten zu ueberzeugen. Vor allem war das Interesse zum heute noch sichtbaren urspruenglichen Landschaftsbild und den sich danach in vielen Bereichen ergebenden Veraenderungen in der Region geweckt. Im Folgenden sollen ein Bild der persoenlichen Eindruecke, eine Einschaetzung des Verfassers zur Situation vor Ort und zeitnahe Aussagen von zugaenglichen Quellen widergespiegelt werden. (orig.)

  19. The Three Gorges Project: How sustainable?

    Science.gov (United States)

    Kepa Brian Morgan, Te Kipa; Sardelic, Daniel N.; Waretini, Amaria F.

    2012-08-01

    SummaryIn 1984 the Government of China approved the decision to construct the Three Gorges Dam Project, the largest project since the Great Wall. The project had many barriers to overcome, and the decision was made at a time when sustainability was a relatively unknown concept. The decision to construct the Three Gorges Project remains contentious today, especially since Deputy Director of the Three Gorges Project Construction Committee, Wang Xiaofeng, stated that "We absolutely cannot relax our guard against ecological and environmental security problems sparked by the Three Gorges Project" (Bristow, 2007; McCabe, 2007). The question therefore was posed: how sustainable is the Three Gorges Project? Conventional approaches to sustainability assessment tend to use monetary based assessment aligned to triple bottom line thinking. That is, projects are evaluated as trade-offs between economic, environmental and social costs and benefits. The question of sustainability is considered using such a traditional Cost-Benefit Analysis approach, as undertaken in 1988 by a CIPM-Yangtze Joint Venture, and the Mauri Model Decision Making Framework (MMDMF). The Mauri Model differs from other approaches in that sustainability performance indicators are considered independently from any particular stakeholder bias. Bias is then introduced subsequently as a sensitivity analysis on the raw results obtained. The MMDMF is unique in that it is based on the Māori concept of Mauri, the binding force between the physical and the spiritual attributes of something, or the capacity to support life in the air, soil, and water. This concept of Mauri is analogous to the Chinese concept of Qi, and there are many analogous concepts in other cultures. It is the universal relevance of Mauri that allows its use to assess sustainability. This research identified that the MMDMF was a strong complement to Cost-Benefit Analysis, which is not designed as a sustainability assessment tool in itself. The

  20. Environmental issues of the Three Gorges project

    International Nuclear Information System (INIS)

    Fang Ziyun

    1994-01-01

    This article addresses the environmental status of the reservoir area, reservoir characteristics, and the information systems used for assessment of environmental impacts. The Three Gorges Project and the environment are examined in detail and benefits for the Yangtze River's middle reaches, the impact of inundation, and impacts on aquatic animals, human health, natural landscape, cultural relics, water temperature and quality, the river estuary, and the surrounding area are considered. (UK)

  1. Assessing internal biophysical vulnerability to landslide hazards - a nested catchment approach: Xiangxi Watershed / Three Gorges Reservoir

    Science.gov (United States)

    Wiegand, Matthias; Seeber, Christoph; Hartmann, Heike; Xiang, Wei; King, Lorenz

    2010-05-01

    The Three Gorges dam construction was completed in 2006. Besides the international media, also the responsible authorities and various scholarly communities pay close attention to potential and actual environmental impacts related to the impoundment and development activities. The geo-environment within the Three Gorges region is highly conducive to landslides. Consequently, a scientific monitoring and risk mitigation system was established and is still under development. Risk analysis with regard to gravity driven mass movements is highly complex and strongly site specific - several aspects hamper a universal methodology applicable for landslide risk and site assessment. The interdisciplinary Sino-German Yangtze-Project Research co-operation aims, among others, to support the sustainable cultivation of the newly developed ecosystems within the Yangtze catchments. Land use change and increasing population growth are causing severe pressure on the scarce land resources. Landslides are acknowledged as important threat, hence vulnerability of certain landscape components have to be identified, quantified and monitored. A nested quantitative approach for vulnerability analysis is developed. The applied risk and vulnerability model understands risk as the product of hazard and vulnerability. Whereas vulnerability is characterized by: mass movement intensity and susceptibility of the respective element at risk. The watershed of Xiangxi river serves as study area. In general, catchment approaches intent and proved to be a functional geographical unit for successful integrated resources management. Several limitations with regard to data accessibility, availability and accuracy have to be considered due to restrictions of feasible scales. Comprehensive large-scale site investigations are confined to training areas for model calibration and validation. Remote sensing potentials are utilised for land use/ land cover change analysis and localization of selected elements

  2. Managing Siting Activities for Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-06-15

    One of the IAEA's statutory objectives is to ''seek to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world''. One way this objective is achieved is through the publication of a range of technical series. Two of these are the IAEA Nuclear Energy Series and the IAEA Safety Standards Series. According to Article III.A.6 of the IAEA Statute, the safety standards establish 'standards of safety for protection of health and minimization of danger to life and property.' The safety standards include the Safety Fundamentals, Safety Requirements and Safety Guides. These standards are written primarily in a regulatory style, and are binding on the IAEA for its own programmes. The principal users are the regulatory bodies in Member States and other national authorities. The IAEA Nuclear Energy Series comprises reports designed to encourage and assist R and D on, and application of, nuclear energy for peaceful uses. This includes practical examples to be used by owners and operators of utilities in Member States, implementing organizations, academia, and government officials, among others. This information is presented in guides, reports on technology status and advances, and best practices for peaceful uses of nuclear energy based on inputs from international experts. The IAEA Nuclear Energy Series complements the IAEA Safety Standards Series. The introduction of nuclear power brings new challenges to States - one of them being the selection of appropriates sites. It is a project that needs to begin early, be well managed, and deploy good communications with all stakeholders; including regulators. This is important, not just for those States introducing nuclear power for the first time, but for any State looking to build a new nuclear power plant. The purpose of the siting activities goes beyond choosing a suitable site and acquiring a licence. A large part of the project is about producing and maintaining a validated

  3. Managing Siting Activities for Nuclear Power Plants

    International Nuclear Information System (INIS)

    2012-01-01

    One of the IAEA's statutory objectives is to ''seek to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world''. One way this objective is achieved is through the publication of a range of technical series. Two of these are the IAEA Nuclear Energy Series and the IAEA Safety Standards Series. According to Article III.A.6 of the IAEA Statute, the safety standards establish 'standards of safety for protection of health and minimization of danger to life and property.' The safety standards include the Safety Fundamentals, Safety Requirements and Safety Guides. These standards are written primarily in a regulatory style, and are binding on the IAEA for its own programmes. The principal users are the regulatory bodies in Member States and other national authorities. The IAEA Nuclear Energy Series comprises reports designed to encourage and assist R and D on, and application of, nuclear energy for peaceful uses. This includes practical examples to be used by owners and operators of utilities in Member States, implementing organizations, academia, and government officials, among others. This information is presented in guides, reports on technology status and advances, and best practices for peaceful uses of nuclear energy based on inputs from international experts. The IAEA Nuclear Energy Series complements the IAEA Safety Standards Series. The introduction of nuclear power brings new challenges to States - one of them being the selection of appropriates sites. It is a project that needs to begin early, be well managed, and deploy good communications with all stakeholders; including regulators. This is important, not just for those States introducing nuclear power for the first time, but for any State looking to build a new nuclear power plant. The purpose of the siting activities goes beyond choosing a suitable site and acquiring a licence. A large part of the project is about producing and maintaining a validated

  4. Quantum mechanical design of enzyme active sites.

    Science.gov (United States)

    Zhang, Xiyun; DeChancie, Jason; Gunaydin, Hakan; Chowdry, Arnab B; Clemente, Fernando R; Smith, Adam J T; Handel, T M; Houk, K N

    2008-02-01

    The design of active sites has been carried out using quantum mechanical calculations to predict the rate-determining transition state of a desired reaction in presence of the optimal arrangement of catalytic functional groups (theozyme). Eleven versatile reaction targets were chosen, including hydrolysis, dehydration, isomerization, aldol, and Diels-Alder reactions. For each of the targets, the predicted mechanism and the rate-determining transition state (TS) of the uncatalyzed reaction in water is presented. For the rate-determining TS, a catalytic site was designed using naturalistic catalytic units followed by an estimation of the rate acceleration provided by a reoptimization of the catalytic site. Finally, the geometries of the sites were compared to the X-ray structures of related natural enzymes. Recent advances in computational algorithms and power, coupled with successes in computational protein design, have provided a powerful context for undertaking such an endeavor. We propose that theozymes are excellent candidates to serve as the active site models for design processes.

  5. Rapid Gorge Formation in an Artificially Created Waterfall

    Science.gov (United States)

    Anton, L.; Mather, A. E.; Stokes, M.; Munoz Martin, A.

    2014-12-01

    A number of studies have examined rates of gorge formation, nick point retreat, and the controls on those rates via bedrock erodibility, the effectiveness of bedrock erosion mechanisms and the role of hillslope processes. Most findings are based on conceptual / empirical models or long term landscape analysis; but studies of recent quantifiable events are scarce yet highly valuable. Here we present expert eye witness account and quantitative survey of large and rapid fluvial erosion events that occurred over an artificially created waterfall at a spillway mouth. In 6 years a ~270 m long, ~100 m deep and ~100 to 160 m wide canyon was carved, and ~1.58 x106 m3 of granite bedrock was removed from the spillway site. Available flow data indicates that the erosion took place under unremarkable flood discharge conditions. The analysis of historic topographic maps enables the reconstruction of the former topography and successive erosion events, enabling the quantification of bedrock erosion amounts, and rates. Analysis of bedrock erodibility and discontinuity patterns demonstrates that the bedrock is mechanically strong, and that similar rock strength and fracture patterns are found throughout the region. It is apparent that structural pre-conditioning through fracture density and orientation in relation to flow and slope direction is of paramount importance in the gorge development. The presented example provides an exceptional opportunity for studying the evolution process of a bedrock canyon and to precisely measure the rate of bedrock channel erosion over a six year period. Results illustrate the highly episodic nature of the erosion and highlight several key observations for the adjustability of bedrock rivers. The observations have implications for the efficiency of bedrock erosion and raise important questions about incision rates, driving mechanisms and timescale assumptions' in models of landscape change.

  6. Long Valley Caldera Lake and reincision of Owens River Gorge

    Science.gov (United States)

    Hildreth, Wes; Fierstein, Judy

    2016-12-16

    Owens River Gorge, today rimmed exclusively in 767-ka Bishop Tuff, was first cut during the Neogene through a ridge of Triassic granodiorite to a depth as great as its present-day floor and was then filled to its rim by a small basaltic shield at 3.3 Ma. The gorge-filling basalt, 200 m thick, blocked a 5-km-long reach of the upper gorge, diverting the Owens River southward around the shield into Rock Creek where another 200-m-deep gorge was cut through the same basement ridge. Much later, during Marine Isotope Stage (MIS) 22 (~900–866 ka), a piedmont glacier buried the diversion and deposited a thick sheet of Sherwin Till atop the basalt on both sides of the original gorge, showing that the basalt-filled reach had not, by then, been reexcavated. At 767 ka, eruption of the Bishop Tuff blanketed the landscape with welded ignimbrite, deeply covering the till, basalt, and granodiorite and completely filling all additional reaches of both Rock Creek canyon and Owens River Gorge. The ignimbrite rests directly on the basalt and till along the walls of Owens Gorge, but nowhere was it inset against either, showing that the basalt-blocked reach had still not been reexcavated. Subsidence of Long Valley Caldera at 767 ka produced a steep-walled depression at least 700 m deeper than the precaldera floor of Owens Gorge, which was beheaded at the caldera’s southeast rim. Caldera collapse reoriented proximal drainages that had formerly joined east-flowing Owens River, abruptly reversing flow westward into the caldera. It took 600,000 years of sedimentation in the 26-km-long, usually shallow, caldera lake to fill the deep basin and raise lake level to its threshold for overflow. Not until then did reestablishment of Owens River Gorge begin, by incision of the gorge-filling ignimbrite.

  7. PAH distribution and mass fluxes in the Three Gorges Reservoir after impoundment of the Three Gorges Dam.

    Science.gov (United States)

    Deyerling, Dominik; Wang, Jingxian; Hu, Wei; Westrich, Bernhard; Peng, Chengrong; Bi, Yonghong; Henkelmann, Bernhard; Schramm, Karl-Werner

    2014-09-01

    Mass fluxes of polycyclic aromatic hydrocarbons (PAHs) were calculated for the Three Gorges Reservoir (TGR) in China, based on concentration and discharge data from the Yangtze River. Virtual Organisms (VOs) have been applied during four campaigns in 2008, 2009 (twice) and 2011 at sampling sites distributed from Chongqing to Maoping. The total PAH mass fluxes ranged from 110 to 2,160 mg s(-1). Highest loads were determined at Chongqing with a decreasing trend towards Maoping in all four sampling campaigns. PAH remediation capacity of the TGR was found to be high as the mass flux reduced by more than half from upstream to downstream. Responsible processes are thought to be adsorption of PAH to suspended particles, dilution and degradation. Furthermore, the dependence of PAH concentration upon water depth was investigated at Maoping in front of the Three Gorges Dam. Although considerable differences could be revealed, there was no trend observable. Sampling of water with self-packed filter cartridges confirmed more homogenous PAH depth distribution. Moreover, PAH content of suspended particles was estimated from water concentrations gathered by VOs based on a water-particle separation model and subsequently compared to PAH concentration measured in water and in filter cartridges. It could be shown that the modeled data predicts the concentration caused by particle-bound PAHs to be about 6 times lower than PAHs dissolved in water. Besides, the model estimates the proportions of 5- and 6-ring PAHs being higher than in water phase. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Power Production Management of Three Gorges Project

    Institute of Scientific and Technical Information of China (English)

    Zhang Cheng

    2010-01-01

    @@ The Three Gorges Hydropower Plant is the one with the largest installed capacity in the world today and has a decisive and important influence upon the security of the national power grids. It has been operated stably and supplied the East China, Central China, South China,Sichuan and Chongqing with clean renewable energy. This paper presents the management of the project's dispatch, operation and maintenance and puts forward new ideas and new methods for the plant management, which may provide valuable references for the operation of oversized hydropower plants.

  9. Power Production Management of Three Gorges Project

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The Three Gorges Hydropower Plant is the one with the largest installed capacity in the world today and has a decisive and important influence upon the security of the national power grids. It has been operated stably and supplied the East China, Central China, South China, Sichuan and Chongqing with clean renewable energy. This paper presents the management of the project’s dispatch, operation and maintenance and puts forward new ideas and new methods for the plant management, which may provide valuable re...

  10. Borehole camera technology and its application in the Three Gorges Project

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.Y.; Sheng, Q.; Ge, X.R. [Chinese Academy of Sciences, Inst. of Rock and Soil Mechanics, Wuhan (China); Law, K.T. [Carleton Univ., Ottawa, ON (Canada)

    2002-07-01

    The China's Three Gorges Project is the world's largest hydropower project, consisting of a 1,983-meter long and 185-meter high dam and 26 power generating units. Borehole examination has been conducted at the site to ensure stability of the slope of the ship lock used for navigation. This paper describes 2 systems for borehole inspection and viewing. Both methods of camera borehole technology provide a unique way for geologic engineers to observe the condition inside a borehole. The Axial-View Borehole Television (AVBTV) provides real-time frontal view of the borehole ahead of the probe, making it possible to detect where holes are blocked and to see cracks and other distinctive features in the strata. The Digital Panoramic Borehole Camera System (DPBCS) can collect, measure, save, analyze, manage and displace geological information about a borehole. It can also be used to determine the orientation of discontinuity, generate unrolled image and virtual core graph and conduct statistical analysis. Both camera systems have been demonstrated successfully at the Three Gorges Project for qualitative description of the borehole as well as for quantitative analysis of cracks existing in the rock. It has been determined that most of the cracks dip in the same general direction as the northern slope of the permanent ship lock of the Three Gorges Project. 12 refs., 1 tab., 9 figs.

  11. Spatiotemporal characteristics of the Huangtupo landslide in the Three Gorges region (China) constrained by radar interferometry

    Science.gov (United States)

    Tomás, R.; Li, Z.; Liu, P.; Singleton, A.; Hoey, T.; Cheng, X.

    2014-04-01

    The Huangtupo landslide is one of the largest in the Three Gorges region, China. The county-seat town of Badong, located on the south shore between the Xiling and Wu gorges of the Yangtze River, was moved to this unstable slope prior to the construction of the Three Gorges Project, since the new Three Gorges reservoir completely submerged the location of the old city. The instability of the slope is affecting the new town by causing residential safety problems. The Huangtupo landslide provides scientists an opportunity to understand landslide response to fluctuating river water level and heavy rainfall episodes, which is essential to decide upon appropriate remediation measures. Interferometric Synthetic Aperture Radar (InSAR) techniques provide a very useful tool for the study of superficial and spatially variable displacement phenomena. In this paper, three sets of radar data have been processed to investigate the Huangtupo landslide. Results show that maximum displacements are affecting the northwest zone of the slope corresponding to Riverside slumping mass I#. The other main landslide bodies (i.e. Riverside slumping mass II#, Substation landslide and Garden Spot landslide) exhibit a stable behaviour in agreement with in situ data, although some active areas have been recognized in the foot of the Substation landslide and Garden Spot landslide. InSAR has allowed us to study the kinematic behaviour of the landslide and to identify its active boundaries. Furthermore, the analysis of the InSAR displacement time-series has helped recognize the different displacement patterns on the slope and their relationships with various triggering factors. For those persistent scatterers, which exhibit long-term displacements, they can be decomposed into a creep model (controlled by geological conditions) and a superimposed recoverable term (dependent on external factors), which appears closely correlated with reservoir water level changes close to the river's edge. These

  12. ESRC guide vanes of hydraulic turbine for Three Gorges project

    Directory of Open Access Journals (Sweden)

    Rui CHEN

    2005-05-01

    Full Text Available The mechanical properties and internal quality of low carbon martensite Electroslag Remelting Casting (ESRCstainless steel castings are superior to that of sand casting ones. The key technologies for the equipments and ESRC processes have been resolved during the experimental research period of guide vanes of hydraulic turbines for Three Gorges project. And ESRC guide vanes of hydraulic turbines for Three Gorges project have been produced successfully.

  13. A milestone for the Three Gorges

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rushu [China Yangzte Three Gorges Project Development Corp., Yichang Hubei (China)

    1999-10-01

    Massive flooding of the Yangtze river in 1998 was a serious cause for concern. The Three Gorges river diversion dam project will reduce the danger. The three construction stages are described. A major milestone was the closure of the Yangtze in 1997 and this was effectively the completion of Stage I. Stage II is construction of the earth-rock cofferdam as a temporary reservoir and the key factor for safe construction of the main stage II works in the dry pit. The cofferdam was filled to flood control elevation and up to July 1998 three peak floods had been handled successfully. Work is in hand for dealing with even higher floods. The 17-year scheme is due for completion in 2009. (UK)

  14. Le barrage des trois Gorges (Chine

    Directory of Open Access Journals (Sweden)

    Luc Merchez

    1999-09-01

    Full Text Available Le barrage des Trois Gorges, en construction sur le Yangzijiang, sera le plus grand barrage au monde. Le gigantisme du projet et sa médiatisation croissante en Occident permettent d'en saisir les enjeux environnementaux et humains. On analyse les grandes caractéristiques du projet et ses conséquences premières avant d'aborder le travail de recherche de l'équipe SIG de l'IGA de Grenoble qui vise à préparer la relocalisation de plus d'un million d'habitants, et à modéliser les impacts démographiques et sociaux.

  15. Ecological operation for Three Gorges Reservoir

    Directory of Open Access Journals (Sweden)

    Wen-xian Guo

    2011-06-01

    Full Text Available The traditional operation of the Three Gorges Reservoir has mainly focused on water for flood control, power generation, navigation, water supply, and recreation, and given less attention to the negative impacts of reservoir operation on the river ecosystem. In order to reduce the negative influence of reservoir operation, ecological operation of the reservoir should be studied with a focus on maintaining a healthy river ecosystem. This study considered ecological operation targets, including maintaining the river environmental flow and protecting the spawning and reproduction of the Chinese sturgeon and four major Chinese carps. Using flow data from 1900 to 2006 at the Yichang gauging station as the control station data for the Yangtze River, the minimal and optimal river environmental flows were analyzed, and eco-hydrological targets for the Chinese sturgeon and four major Chinese carps in the Yangtze River were calculated. This paper proposes a reservoir ecological operation model, which comprehensively considers flood control, power generation, navigation, and the ecological environment. Three typical periods, wet, normal, and dry years, were selected, and the particle swarm optimization algorithm was used to analyze the model. The results show that ecological operation modes have different effects on the economic benefit of the hydropower station, and the reservoir ecological operation model can simulate the flood pulse for the requirements of spawning of the Chinese sturgeon and four major Chinese carps. According to the results, by adopting a suitable re-operation scheme, the hydropower benefit of the reservoir will not decrease dramatically while the ecological demand is met. The results provide a reference for designing reasonable operation schemes for the Three Gorges Reservoir.

  16. Analysis of the relationship between water level fluctuation and seismicity in the Three Gorges Reservoir (China

    Directory of Open Access Journals (Sweden)

    Lifen Zhang

    2017-03-01

    Full Text Available The Three Gorges Reservoir is a good site for the further researches on reservoir induced seismicity due to decades' seismic monitoring. After the first water impounding in 2003, seismic activity becomes more frequent than that before water impoundment. In order to quantitatively study, the relationship between the water level fluctuation and earthquakes in TGR, we introduced statistical methods to attain the goal. First of all, we relocated the earthquakes in TGR region with double difference method and divided the earthquakes into 5 clusters with clustering analysis method. Secondly, to examine the impacts of water level fluctuation in different water filling stages on the seismic activity in the 5 clusters, a series of statistical analyses are applied. Pearson correlation results show that only the 175 m water level fluctuation has significantly positive impacts on the seismic activity in clusters Ⅰ, Ⅱ, Ⅲ and Ⅴ with correlation coefficients of 0.44, 0.38, 0.66 and 0.63. Cross-correlation analysis demonstrates that 0, 1, 0 and 0 month time delay separately for the clusters Ⅰ, Ⅱ, Ⅲ and Ⅴ exists. It illustrated the influences of the water loading and pore pressure diffusion on induced earthquakes. Cointegration tests and impulse response analysis denoted that the 175 m water level only had long term and significant effects just on the seismic events in the intersection region of the Fairy Mount Fault and Nine-brook Fault. One standard deviation shock to 175 m water level increased the seismic activity in cluster Ⅴ for the first 3 months, and then the negative influence was shown. After 7 months, the negative impulse response becomes stable. The long-term effect of the 175 m water impoundment also proved the important role of pore pressure diffusion in RIS with time.

  17. Passive seismic experiment in the Olduvai Gorge and Laetoli region (Ngorongoro Conservation Area), Northern Tanzania.

    Science.gov (United States)

    Parisi, Laura; Lombardo, Luigi; Tang, Zheng; Mai, P. Martin

    2017-04-01

    The Olduvai Gorge and Laetoli basins, located within the Ngorogoro Conservation Area (NCA), are a cornerstone for understanding the evolution of early humans and are two paleo-antropological excavation sites of global importance. NCA is located at the boundary between the Tanzanian Craton and East African Rift (EAR), in the vicinity of Ngorongoro Crater and other major volcanic edifices. Thus, understanding the geology and tectonics of the NCA may shed light onto the question why early Hominins settled in this region. Environmental and geological conditions in the Olduvai and Laetoli region that promoted human settlement and development are still debated by geologists and paleo-anthropologists. Paleo-geographical reconstructions of the study area of the last 2 million years may take advantage of modern passive seismology. Therefore, we installed a dense seismic network covering a surface of approximately 30 x 40 km within the NCA to map the depth extent of known faults, and to identify seismically active faults that have no surface expression. Our ten seismic stations, equipped with Trillium Compact 120 s sensors, started to operate in June 2016 and will continue for a total of 2 years. At the end of the first year, other 5 stations will densify our network. Here we analyse data quality of the first four months of continuous recordings. Our network provides good quality 3-C waveforms in the frequency range of 0.7-50 Hz. Vertical component seismograms record frequencies reliably down to 8 mHz. Preliminary results of the seismicity obtained with standard location procedures show that NCA is characterised by frequent tectonic seismicity (not volcano-related) with Ml between 0.5 and 2.0. Seismic activity is more frequent in the South (Laetoli region) where major fault systems have not been recognised at the surface yet.

  18. Tectonic environment and cause of earthquakes in the Three Gorges reservoir area

    Directory of Open Access Journals (Sweden)

    Li Qiang

    2011-02-01

    Full Text Available Seismotectonics in the Three Gorges reservoir area is investigated by using the P-wave tomography with earthquakes that occurred before the impoundment of the reservoir. The result indicates that most of these events occurred in or around the velocity-gradient belts between high-velocity and low-velocity anomalies. These belts have similar characteristics to bured-fault zones. Stresses generated by movement of partially molten upper-mantle materials and thermal stress may have jointly contributed to the seismic activities along the faults and such buried faults, and possibly activated new earthquake ruptures.

  19. Seismic hazard assessment of the Three Gorges Project

    Directory of Open Access Journals (Sweden)

    Yao Yunsheng

    2013-05-01

    Full Text Available Seismic monitoring data for the past 50 years in the Three Gorges Reservoir area show that the reservoir head area is a typical weak seismic region with low seismicity before impoundment and that the epicenters were concentrated in the east and west sides of the Zigui Basin, most of which were natural tectonic earthquakes. After impoundment, the seismic activity shifted to the segment between Badong and Zigui along the Yangtze River, mainly within 5 km of the reservoir bank. The seismogenesis was categorized into four types; Karst collapse earthquakes, earthquakes caused by Karst gas explosion, mining tunnel collapse earthquakes, and rock (terrane slip earthquakes, all of which are related to the lithology, structure, and tectonics of near-surface geological bodies of the area. Compared with the seismicity before impoundment, the seismic frequency increase was remarkable, with most of the magnitudes below Ms2. 0. Therefore, the intensity of the earthquakes remained at a low level. On November 22, 2008, a magnitude 4. 1 earthquake, the largest earthquake recorded since impoundment, occurred in Quyuan Town, Zigui County. The intensity and PGA of reservoir-induced earthquakes are higher than those of tectonic earthquakes with equal magnitude, but the peak intensity of reservoir-induced earthquakes is not likely to go beyond that of the estimated range from earlier studies.

  20. Activities on the site during construction phase

    International Nuclear Information System (INIS)

    Fickel, O.F.

    1977-01-01

    A survey is given of the work done on the site from site-opening till turn over of the plant to the client. After a short introduction to time schedules, manpower on site, site facilities and civil work and constructions, the commissioning and trial operation phase is discussed in detail. This phase begins with finishing the assembly of individual systems and components and ends with the trial operation and the acceptance measurement. During this period the subsystems are started-up in a useful sequence, first from cold, then from hot conditions and are finally operated as a total with nuclear energy. The single steps are: a) commissioning of indivudal systems; b) hot functional test 1 (without fuels) c) baseline inspection at the reactor pressure vessel; d) hot functional test 2 (with fuels); e) preparation for first criticality; f) postcriticality test program; g) trial operation: h) acceptance measurement. (HP) [de

  1. Atmospheric deposition inputs and effects on lichen chemistry and indicator species in the Columbia River Gorge, USA

    International Nuclear Information System (INIS)

    Fenn, M.E.; Geiser, L.; Bachman, R.; Blubaugh, T.J.; Bytnerowicz, A.

    2007-01-01

    Topographic and meteorological conditions make the Columbia River Gorge (CRG) an 'exhaust pipe' for air pollutants generated by the Portland-Vancouver metropolis and Columbia Basin. We sampled fog, bulk precipitation, throughfall, airborne particulates, lichen thalli, and nitrophytic lichen distribution. Throughfall N and S deposition were high, 11.5-25.4 and 3.4-6.7 kg ha -1 over 4.5 months at all 9 and 4/9 sites, respectively. Deposition and lichen thallus N were highest at eastern- and western-most sites, implicating both agricultural and urban sources. Fog and precipitation pH were frequently as low as 3.7-5.0. Peak NO x , NH 3 , and SO 2 concentrations in the eastern CRG were low, suggesting enhanced N and S inputs were largely from particulate deposition. Lichens indicating nitrogen-enriched environments were abundant and lichen N and S concentrations were 2x higher in the CRG than surrounding national forests. The atmospheric deposition levels detected likely threaten Gorge ecosystems and cultural resources. - Nitrogen, sulfur and acidic deposition threaten natural and cultural resources in the Columbia River Gorge National Scenic Area

  2. Diversity of microbial plankton across the Three Gorges Dam of the Yangtze River, China

    Directory of Open Access Journals (Sweden)

    Shang Wang

    2012-05-01

    Full Text Available The Three Gorges Dam (TGD of the Yangtze River, China, is one of the largest irrigation and hydroelectric engineering projects in the world. The effects of huge man-made projects like TGD on fauna and macrophyte are obvious, mainly through changes of water dynamics and flow pattern; however, it is less clear how microorganisms respond to such changes. This research was aimed to examine differences in microbial diversity at different seasons and locations (in front of and behind the TGD. In addition, differences between particle-attached and free-living communities were also examined. The community structures of total and potentially active microorganisms in the water columns behind and in front of the TGD were analyzed with the DNA- and RNA-based 16S rRNA gene phylogenetic approaches over three different seasons. Clone libraries of 16S rRNA genes were prepared after amplification from extracted DNA and, for some samples, after preparing cDNA from extracted rRNA. Differences were observed between sites at different seasons and between free-living and particle-attached communities. Both bacterial and archaeal communities were more diverse in summer than in winter, due to higher nutrient levels and warmer temperature in summer than in winter. Particle-attached microorganisms were more diverse than free-living communities, possibly because of higher nutrient levels and heterogeneous geochemical micro-environments in particles. Spatial variations in bacterial community structure were observed, i.e., the water reservoir behind the TGD (upstream hosted more diverse bacterial populations than in front of the dam (downstream, because of diverse sources of sediments and waters from upstream to the reservoir. These results have important implications for our understanding of responses of microbial communities to environmental changes in river ecosystems affected by dam construction.

  3. Development of METAL-ACTIVE SITE and ZINCCLUSTER tool to predict active site pockets.

    Science.gov (United States)

    Ajitha, M; Sundar, K; Arul Mugilan, S; Arumugam, S

    2018-03-01

    The advent of whole genome sequencing leads to increasing number of proteins with known amino acid sequences. Despite many efforts, the number of proteins with resolved three dimensional structures is still low. One of the challenging tasks the structural biologists face is the prediction of the interaction of metal ion with any protein for which the structure is unknown. Based on the information available in Protein Data Bank, a site (METALACTIVE INTERACTION) has been generated which displays information for significant high preferential and low-preferential combination of endogenous ligands for 49 metal ions. User can also gain information about the residues present in the first and second coordination sphere as it plays a major role in maintaining the structure and function of metalloproteins in biological system. In this paper, a novel computational tool (ZINCCLUSTER) is developed, which can predict the zinc metal binding sites of proteins even if only the primary sequence is known. The purpose of this tool is to predict the active site cluster of an uncharacterized protein based on its primary sequence or a 3D structure. The tool can predict amino acids interacting with a metal or vice versa. This tool is based on the occurrence of significant triplets and it is tested to have higher prediction accuracy when compared to that of other available techniques. © 2017 Wiley Periodicals, Inc.

  4. Temperature changes in Three Gorges Reservoir Area and linkage with Three Gorges Project

    Science.gov (United States)

    Song, Zhen; Liang, Shunlin; Feng, Lian; He, Tao; Song, Xiao-Peng; Zhang, Lei

    2017-05-01

    The Three Gorges Project (TGP) is one of the largest hydroelectric projects throughout the world. It has brought many benefits to the society but also led to endless debates about its environmental and climatic impacts. Monitoring the spatiotemporal variations of temperature in the Three Gorges Reservoir Area (TGRA) is important for understanding the climatic impacts of the TGP. In this study, we used remote sensing-based land surface temperature (LST) and ground-measured air temperature data to investigate temperature changes in the TGRA. Results showed that during the daytime in summer, LST exhibited significant cooling (1-5°C) in the downstream region of the reservoir, whereas LST during the nighttime in winter exhibited significant warming (1-5°C) across the entire reservoir. However, these cooling and warming effects were both locally constrained within 5 km buffer along the reservoir. The changes in air temperature were consistent with those in LST, with 0.67°C cooling in summer and 0.33°C warming in winter. The temperature changes along the reservoir not only resulted from the land-water conversion induced by the dam impounding but were also related to the increase of vegetation cover caused by the ecological restoration projects. Significant warming trends were also found in the upstream of TGRA, especially during the daytime in summer, with up to 5°C for LST and 0.52°C for air temperature. The warming was caused mainly by urban expansion, which was driven in part by the population resettlement of TGP. Based on satellite observations, we investigated the comprehensive climatic impacts of TGP caused by multiple factors.

  5. Savannah River Site prioritization of transition activities

    International Nuclear Information System (INIS)

    Finley, R.H.

    1993-11-01

    Effective management of SRS conversion from primarily a production facility to other missions (or Decontamination and Decommissioning (D ampersand D)) requires a systematic and consistent method of prioritizing the transition activities. This report discusses the design of a prioritizing method developed to achieve systematic and consistent methods of prioritizing these activities

  6. Water exposure assessment of aryl hydrocarbon receptor agonists in Three Gorges Reservoir, China using SPMD-based virtual organisms.

    Science.gov (United States)

    Wang, Jingxian; Bernhöft, Silke; Pfister, Gerd; Schramm, Karl-Werner

    2014-10-15

    SPMD-based virtual organisms (VOs) were deployed at five to eight sites in the Three Gorges Reservoir (TGR), China for five periods in 2008, 2009 and 2011. The water exposure of aryl hydrocarbon receptor (AhR) agonists was assessed by the VOs. The chosen bioassay response for the extracts of the VOs, the induction of 7-ethoxyresorufin-O-deethylase (EROD) was assayed using a rat hepatoma cell line (H4IIE). The results show that the extracts from the VOs could induce AhR activity significantly, whereas the chemically derived 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalent (TEQcal) accounted for water level reached a maximum of 175 m. Although the aqueous concentration of AhR agonists of 0.8-4.8 pg TCDDL(-1) in TGR was not alarming, the tendency of accumulating high concentration of AhR agonists in VO lipid and existence of possible synergism or antagonism in the water may exhibit a potential hazard to local biota being exposed to AhR agonists. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Safety Oversight of Decommissioning Activities at DOE Nuclear Sites

    International Nuclear Information System (INIS)

    Zull, Lawrence M.; Yeniscavich, William

    2008-01-01

    The Defense Nuclear Facilities Safety Board (Board) is an independent federal agency established by Congress in 1988 to provide nuclear safety oversight of activities at U.S. Department of Energy (DOE) defense nuclear facilities. The activities under the Board's jurisdiction include the design, construction, startup, operation, and decommissioning of defense nuclear facilities at DOE sites. This paper reviews the Board's safety oversight of decommissioning activities at DOE sites, identifies the safety problems observed, and discusses Board initiatives to improve the safety of decommissioning activities at DOE sites. The decommissioning of former defense nuclear facilities has reduced the risk of radioactive material contamination and exposure to the public and site workers. In general, efforts to perform decommissioning work at DOE defense nuclear sites have been successful, and contractors performing decommissioning work have a good safety record. Decommissioning activities have recently been completed at sites identified for closure, including the Rocky Flats Environmental Technology Site, the Fernald Closure Project, and the Miamisburg Closure Project (the Mound site). The Rocky Flats and Fernald sites, which produced plutonium parts and uranium materials for defense needs (respectively), have been turned into wildlife refuges. The Mound site, which performed R and D activities on nuclear materials, has been converted into an industrial and technology park called the Mound Advanced Technology Center. The DOE Office of Legacy Management is responsible for the long term stewardship of these former EM sites. The Board has reviewed many decommissioning activities, and noted that there are valuable lessons learned that can benefit both DOE and the contractor. As part of its ongoing safety oversight responsibilities, the Board and its staff will continue to review the safety of DOE and contractor decommissioning activities at DOE defense nuclear sites

  8. Canyons and gorges as potential geotourism destinations in Serbia: comparative analysis from two perspectives - general geotourists' and pure geotourists'

    Science.gov (United States)

    Božić, Sanja; Tomić, Nemanja

    2015-10-01

    Serbia represents one of those countries which have not yet differentiated themselves on the world tourism map. However, it has an immense but still unrevealed potential for geotourism development. In this paper we analyzed several remarkable canyons and gorges of great scientific importance and geotourism potential. These sites include the Djerdap Gorge and Lazar River Canyon, located in Eastern Serbia and the Ovcar-Kablar Gorge and Uvac Canyon located in Western Serbia. One of the main goals of this paper was to analyze and compare the current state and tourism potential of these geosites by using the M-GAM model for geosite assessment. However, the principal aim of the paper is to analyze how important is each subindicator in the assessment process for different market segments. In this paper, we also analyzed how giving different importance to subindicators can influence the position of the geosites in the matrix indicating different assessment done by two chosen market segments. The research showed that general geotourists appreciate considerably different values when assessing a geosite in comparison to pure geotourists. The paper can be used as framework for developing the tourism management strategy of geosites taking into consideration the needs and preferences of the target market segments.

  9. Assessment of the Physicochemical Quality of Challawa Gorge Dam ...

    African Journals Online (AJOL)

    Dr Maimuna

    Water and sediment samples were collected from Challawa Gorge dam during the wet and dry seasons and analyzed for some physicochemical parameters, heavy metals (Cd, Cr, Mn, Pb, Zn) and minerals (Na and K) using Atomic Absorption Spectrophotometric and Flame Photometric techniques. The results showed the.

  10. Diversity of macrofungal community in Bifeng Gorge: the core giant ...

    African Journals Online (AJOL)

    Macrofungi not only play an important role in pollution control and other environmental protection measures, but also an important resource in food and pharmaceutical industries. However, the diversity of the macrofungal community in the core habitat of the giant panda in Bifeng Gorge, China is still inadequate. In the ...

  11. Accumulation of floating microplastics behind the Three Gorges Dam

    International Nuclear Information System (INIS)

    Zhang, Kai; Gong, Wen; Lv, Jizhong; Xiong, Xiong; Wu, Chenxi

    2015-01-01

    We investigated the occurrence and distribution of microplastics in surface water from the Three Gorges Reservoir. Nine samples were collected via trawl sampling with a 112 μm mesh net. The abundances of microplastics were from 3407.7 × 10 3 to 13,617.5 × 10 3 items per square kilometer in the main stream of the Yangtze River and from 192.5 × 10 3 to 11,889.7 × 10 3 items per square kilometer in the estuarine areas of four tributaries. The abundance of microplastics in the main stream of the Yangtze River generally increased as moving closer to the Three Gorges Dam. The microplastics are made exclusively of polyethylene (PE), polypropylene (PP), and polystyrene (PS). Together with microplastics, high abundance of coal/fly ash was also observed in the surface water samples. Comparing with previously reported data, microplastics in the TGR were approximately one to three orders of magnitudes greater, suggesting reservoirs as potential hot spot for microplastic pollution. - Highlights: • Occurrence of microplastics was studied in surface water from the Three Gorges Reservoir. • Microplastics were identified as polyethylene, polypropylene, and polystyrene. • Abundance of microplastics was considerably higher than previously reported data. - Microplastics were observed in high abundance in surface water from the Three Gorges Reservoir implying reservoirs as structural controls where microplastics accumulate

  12. Arthropod diversity and abundance along the Kihansi Gorge ...

    African Journals Online (AJOL)

    Arthropod diversity and abundance at the order level was investigated along the Kihansi Gorge in the southern Udzungwa Mountains between June and August 1997 by using sweep netting, timed Lepidoptera counts, malaise-traps, solar powered light-¬traps, baited pitfall-traps, sticky-traps and baited butterfly traps.

  13. Mosquito population dynamics during the construction of Three Gorges Dam in Yangtze River, China.

    Science.gov (United States)

    Guo, Yuhong; Lai, ShengJie; Zhang, Jing; Liu, Qiyong; Zhang, Huaiqing; Ren, Zhoupeng; Mao, Deqiang; Luo, Chao; He, Yuanyuan; Wu, Haixia; Li, Guichang; Ren, Dongsheng; Liu, Xiaobo; Chang, Zhaorui

    2018-06-01

    Mosquitoes are responsible for spreading many diseases and their populations are susceptible to environmental changes. The ecosystems in the Three Gorges Region were probably altered because of changes to the environment during the construction of the Three Gorges Dam (TGD), the world's largest hydroelectric dam by generating capacity. We selected three sites at which to monitor the mosquitoes from 1997 to 2009. We captured adult mosquitoes with battery-powered aspirators fortnightly between May and September of each year in dwellings and sheds. We identified the mosquito species, and examined changes in the species density during the TGD construction. We monitored changes in the species and density of mosquitoes in this area for 13 years during the TGD construction and collected information that could be used to support the control and prevention of mosquito-borne infections. We found that the mosquito species composition around the residential areas remained the same, and the density changed gradually during the TGD construction. The changes in the populations tended to be consistent over the years, and the densities were highest in July, and were between 3 and 5 times greater in the sheds than in the dwellings. The mosquito species and populations remained stable during the construction of the TGD. The mosquito density may have increased as the reservoir filled, and may have decreased during the clean-up work. Clean-up work may be an effective way to control mosquitoes and prevent mosquito-borne diseases. Copyright © 2018. Published by Elsevier B.V.

  14. Flood management selections for the Yangtze River midstream after the Three Gorges Project operation

    Science.gov (United States)

    Fang, Hongwei; Han, Dong; He, Guojian; Chen, Minghong

    2012-04-01

    SummaryAfter the Yangtze River was closed by the Three Gorges Project (TGP) in 2003, erosion occurred from the dam site to the river mouth, especially in the middle and lower reaches of the Yangtze River. However, in some local areas of Chenglingji reach which holds the key position for flood management, there is actually deposition in contrast to the expected erosion. In this paper, a one dimensional mathematical model of the river network with sediment transport is used as the tool to simulate flow and fluvial processes. The calculation domain is from Yichang, which is downstream of the dam, to Hankou, the controlling node of flood management, 694 km long in total. The model is calibrated based on the field data of hydrology and sediment transport during the period from October 2003 to October 2008. Then the model is utilized to simulate the erosion and deposition of the middle and lower reaches of the Yangtze River in the next two decades, and produce the results of a new river channel after river bed deformation occurs. The typical flood processes of 1954 and 1998 in the Yangtze River basin are used to check the flood management scheme for the research area, and results show that water storage of Three Gorges Reservoir (TGR) and a flood diversion program downstream of the Yangtze River should be taken into consideration.

  15. The Project for Developing Countermeasures against Landslides in the Abay River Gorge, Ethiopia

    Science.gov (United States)

    Guta, H. E.

    2016-12-01

    The Blue Nile Gorge of Ethiopia is characterized by high relief landscape. The stretch of major arterial road that connects Ethiopia to Sudan passes through the Gorge. The Gorge is plagued by swarms of landslides which makes it a tremendous obstacle for travel and communication. Therefore, landside study was carried out from 2010 to 2012 by JICA and Geological survey of Ethiopia to figure out the mechanisms that trigger the swarms of landslides that occur in the area and identify appropriate countermeasures that would be best implemented. The study included geomorphologic and geologic survey, drilling survey, displacement monitoring, ground water and precipitation monitoring, geophysical exploration, and stability analysis. About 42 landslide monitoring instruments namely extensometers (both surface and borehole), inclinometers and ground water level meters were installed in four highly landslide prone areas to detect slip surface, and determine amount and direction of movement. The amount of landslide movement at the four zones is 42.4, 57.6, 294.9 and 136mm during rainy season. Ground water level rising, nature of material and intense rainfall are found to be among the major triggering factors. Stability analysis using Simple Jambu and modified Fellenus methods was conducted resulting in safety factor Fs less than one and reasonably 0.98 by adopting shear parameters of soils by back analysis. By assuming cohesion (c') to be very close to 0 due to landslide blocks active movement when ground water rises during rainy season, Shear resistance angle, ɸ, was obtained to be 10.80, 26.30, 10.20 and 16.30 in the four areas using Modified Fellenius method and 10.70, 26.60, 10.00 and 16.10 using Simple Janbu method. Effect of countermeasures was checked by trial calculation. Accordingly the factory of safety increased from 0.98 to 1.2 when ɸ=60, ground water is lowered by 6m, and steel pipe pile of ɸ500mm x t40mm at an interval of 1.9m are implemented. consequently

  16. Robotics at Savannah River site: activity report

    International Nuclear Information System (INIS)

    Byrd, J.S.

    1984-09-01

    The objectives of the Robotics Technology Group at the Savannah River Laboratory are to employ modern industrial robots and to develop unique automation and robotic systems to enhance process operations at the Savannah River site (SRP and SRL). The incentives are to improve safety, reduce personnel radiation exposure, improve product quality and productivity, and to reduce operating costs. During the past year robotic systems have been installed to fill chemical dilution vials in a SRP laboratory at 772-F and remove radioactive waste materials in the SRL Californium Production Facility at 773-A. A robotic system to lubricate an extrusion press has been developed and demonstrated in the SRL robotics laboratory and is scheduled for installation at the 321-M fuel fabrication area. A mobile robot was employed by SRP for a radiation monitoring task at a waste tank top in H-Area. Several other robots are installed in the SRL robotics laboratories and application development programs are underway. The status of these applications is presented in this report

  17. Linking Ah receptor mediated effects of sediments and impacts on fish to key pollutants in the Yangtze Three Gorges Reservoir, China - A comprehensive perspective.

    Science.gov (United States)

    Floehr, Tilman; Scholz-Starke, Björn; Xiao, Hongxia; Hercht, Hendrik; Wu, Lingling; Hou, Junli; Schmidt-Posthaus, Heike; Segner, Helmut; Kammann, Ulrike; Yuan, Xingzhong; Roß-Nickoll, Martina; Schäffer, Andreas; Hollert, Henner

    2015-12-15

    The Three Gorges Reservoir (TGR), created in consequence of the Yangtze River's impoundment by the Three Gorges Dam, faces numerous anthropogenic impacts that challenge its unique ecosystem. Organic pollutants, particularly aryl hydrocarbon receptor (AhR) agonists, have been widely detected in the Yangtze River, but only little research was yet done on AhR-mediated activities. Hence, in order to assess effects of organic pollution, with particular focus on AhR-mediated activities, several sites in the TGR area were examined applying the "triad approach". It combines chemical analysis, in vitro, in vivo and in situ investigations to a holistic assessment. Sediments and the benthic fish species Pelteobagrus vachellii were sampled in 2011/2012, respectively, to identify relevant endpoints. Sediment was tested in vitro with the ethoxyresorufin-O-deethylase (EROD) induction assay, and in vivo with the Fish Embryo Toxicity Test and Sediment Contact Assay with Danio rerio. Activities of phase I (EROD) and phase II (glutathione-S-transferase) biotransformation enzymes, pollutant metabolites and histopathological alterations were studied in situ in P. vachellii. EROD induction was tested in vitro and in situ to evaluate possible relationships. Two sites, near Chongqing and Kaixian city, were identified as regional hot-spots and further investigated in 2013. The sediments induced in the in vitro/in vivo bioassays AhR-mediated activities and embryotoxic/teratogenic effects - particularly on the cardiovascular system. These endpoints could be significantly correlated to each other and respective chemical data. However, particle-bound pollutants showed only low bioavailability. The in situ investigations suggested a rather poor condition of P. vachellii, with histopathological alterations in liver and excretory kidney. Fish from Chongqing city exhibited significant hepatic EROD induction and obvious parasitic infestations. The polycyclic aromatic hydrocarbon (PAH) metabolite 1

  18. Eskers and bedrock gorges (tunnel valleys in the Pakasaivo area, western Finnish Lapland

    Directory of Open Access Journals (Sweden)

    Peter Johansson

    2003-01-01

    Full Text Available Studies of the deglaciation of the last Scandinavian Ice Sheet, including the behavior of the ice sheet and meltwater activity, were conducted in the vicinity of the Pakasaivo canyon lake, located in western Finnish Lapland. Pakasaivo itself, a circular basin up to 100 m deep, was formed in the broken bedrock by glacial erosion and meltwater streams. It was originally related to a former subglacial meltwater system, including the deep Keinokursu gorge. Both this gorge and the Pakasaivo canyon lake were formed subglacially duringan early stage of deglaciation. It was characterized by intense meltwater erosion, which in Pakasaivo also seems to have generated a strong whirl. Steep-crested esker ridges were subsequently deposited; subaerial meltwater activity then followed. Finally the meltwaterwas discharged from the ice-dammed lake north of the area and passed through the Pakasaivo canyon to the ice-free areas. This caused additional intense erosion of the canyon floor and walls, and the deep circular basin is highly similar to a plunge pool formed at the base of a cataract.

  19. Active sites environmental monitoring Program - Program Plan: Revision 2

    International Nuclear Information System (INIS)

    Morrissey, C.M.; Hicks, D.S.; Ashwood, T.L.; Cunningham, G.R.

    1994-05-01

    The Active Sites Environmental Monitoring Program (ASEMP), initiated in 1989, provides early detection and performance monitoring of active low-level-waste (LLW) and transuranic (TRU) waste facilities at Oak Ridge National Laboratory (ORNL). Several changes have recently occurred in regard to the sites that are currently used for waste storage and disposal. These changes require a second set of revisions to the ASEMP program plan. This document incorporates those revisions. This program plan presents the organization and procedures for monitoring the active sites. The program plan also provides internal reporting levels to guide the evaluation of monitoring results

  20. Tritium activities in selected wells on the Nevada Test Site

    International Nuclear Information System (INIS)

    Lyles, B.F.

    1993-05-01

    Literature and data were reviewed related to radionuclides in groundwater on and near the Nevada Test Site. No elevated tritium activities have been reported outside of the major testing regions of the Nevada Test Site. Three wells were identified as having water with above-background (>50 pCi/l) tritium activities: UE-15d Water Well; USGS Water Well A; and USGS Test Well B Ex. Although none of these wells have tritium activities greater than the Nevada State Drinking Water standard (20,000 pCi/l), their time-series tritium trends may be indicative to potential on-site radionuclide migration

  1. Occurrence of organotin compounds in river sediments under the dynamic water level conditions in the Three Gorges Reservoir Area, China.

    Science.gov (United States)

    Gao, Jun-Min; Zhang, Ke; Chen, You-Peng; Guo, Jin-Song; Wei, Yun-Mei; Jiang, Wen-Chao; Zhou, Bin; Qiu, Hui

    2015-06-01

    The Three Gorges Project is the largest hydro project in the world, and the water level of the Three Gorges Reservoir (TGR) is dynamic and adjustable with the aim of flood control and electrical power generation. It is necessary to investigate the pollutants and their underlying contamination processes under dynamic water levels to determine their environmental behaviors in the Three Gorges Reservoir Area (TGRA). Here, we report the assessment of organotin compounds (OTs) pollution in the river sediments of the TGRA. Surface sediment samples were collected in the TGRA at low and high water levels. Tributyltin (TBT), triphenyltin (TPhT), and their degradation products in sediments were quantified by gas chromatography-mass spectrometry. Butyltins (BTs) and phenyltins (PhTs) were detected in sediments, and BTs predominated over PhTs in the whole study area under dynamic water level conditions. The concentrations of OTs in sediments varied markedly among locations, and significant concentrations were found in river areas with high levels of boat traffic and wastewater discharge. Sediments at all stations except Cuntan were lightly contaminated with TBT, and total organic carbon (TOC) was a significant factor affecting the fate of TBT in the TGRA. The butyltin and phenyltin degradation indices showed no recent inputs of TBT or TPhT into this region, with the exception of fresh TPhT input at Xiakou Town. Shipping activity, wastewater discharge, and agriculture are the most likely sources of OTs in the TGRA.

  2. Active site - a site of binding of affinity inhibitors in baker's yeast inorganic pyrophosphatase

    International Nuclear Information System (INIS)

    Svyato, I.E.; Sklyankina, V.A.; Avaeva, S.M.

    1986-01-01

    The interaction of the enzyme-substrate complex with methyl phosphate, O-phosphoethanolamine, O-phosphopropanolamine, N-acetylphosphoserine, and phosphoglyolic acid, as well as pyrophosphatase, modified by monoesters of phosphoric acid, with pyrophosphate and tripolyphosphate, was investigated. It was shown that the enzyme containing the substrate in the active site does not react with monophosphates, but modified pyrophosphatase entirely retains the ability to bind polyanions to the regulatory site. It is concluded that the inactivation of baker's yeast inorganic pyrophosphatase by monoesters of phosphoric acid, which are affinity inhibitors of it, is the result of modification of the active site of the enzyme

  3. Olduvai Gorge, Shaded Relief and Colored Height

    Science.gov (United States)

    2004-01-01

    Three striking and important areas of Tanzania in eastern Africa are shown in this color-coded shaded relief image from the Shuttle Radar Topography Mission. The largest circular feature in the center right is the caldera, or central crater, of the extinct volcano Ngorongoro. It is surrounded by a number of smaller volcanoes, all associated with the Great Rift Valley, a geologic fault system that extends for about 4,830 kilometers (2,995 miles) from Syria to central Mozambique. Ngorongoro's caldera is 22.5 kilometers (14 miles) across at its widest point and is 610 meters (2,000 feet) deep. Its floor is very level, holding a lake fed by streams running down the caldera wall. It is part of the Ngorongoro Conservation Area and is home to over 75,000 animals. The lakes south of the crater are Lake Eyasi and Lake Manyara, also part of the conservation area. The relatively smooth region in the upper left of the image is the Serengeti National Park, the largest in Tanzania. The park encompasses the main part of the Serengeti ecosystem, supporting the greatest remaining concentration of plains game in Africa including more than 3,000,000 large mammals. The animals roam the park freely and in the spectacular migrations, huge herds of wild animals move to other areas of the park in search of greener grazing grounds (requiring over 4,000 tons of grass each day) and water. The faint, nearly horizontal line near the center of the image is Olduvai Gorge, made famous by the discovery of remains of the earliest humans to exist. Between 1.9 and 1.2 million years ago a salt lake occupied this area, followed by the appearance of fresh water streams and small ponds. Exposed deposits show rich fossil fauna, many hominid remains and items belonging to one of the oldest stone tool technologies, called Olduwan. The time span of the objects recovered dates from 2,100,000 to 15,000 years ago. Two visualization methods were combined to produce the image: shading and color coding of

  4. Sternoe study site. Scope of activities and main results

    International Nuclear Information System (INIS)

    Ahlbom, K.; Andersson, J.E.; Nordqvist, R.; Tiren, S.; Ljunggren, C.; Voss, C.

    1992-01-01

    During the period from 1977-1986 SKB (Swedish Nuclear Fuel and Waste Management Co) performed surface and borehole investigations of 14 study sites for the purpose of assessing their suitability for a repository of spent nuclear fuel. The next phase in the SKB site selection programme will be to perform detailed characterization, including characterization from shafts and/or tunnels, of two or three sites. The detailed investigations will continue over several years to provide all the data needed for a licensing application to build a repository. Such an application is foreseen to be given to the authorities around the year 2003. It is presently not clear if anyone of the previously investigated study sites will be selected as a site for detailed characterization. Other sites with geological and/or socio-economical characteristics judged more favourable may very well be the ones selected. However, as a part of the background documentation needed for the site selection studies to come, summary reports will be prepared for most study sites. These reports will include scope of activities, main results, uncertainties and need of complementary investigations. This report concerns the Sternoe study site. This site was one of the first sites to be investigated by SKB . The studies at Sternoe were made under severe time-constraints and with prototype borehole instrumentations. These limitations should be kept in mind when reading the report. (41 refs., 16 figs., 12 tabs.) (au)

  5. Environmental impact assessments of the Three Gorges Project in China: Issues and interventions

    Science.gov (United States)

    Xu, Xibao; Tan, Yan; Yang, Guishan

    2013-09-01

    The paper takes China's authoritative Environmental Impact Statement for the Yangzi (Yangtze) Three Gorges Project (TGP) in 1992 as a benchmark against which to evaluate emerging major environmental outcomes since the initial impoundment of the Three Gorges reservoir in 2003. The paper particularly examines five crucial environmental aspects and associated causal factors. The five domains include human resettlement and the carrying capacity of local environments (especially land), water quality, reservoir sedimentation and downstream riverbed erosion, soil erosion, and seismic activity and geological hazards. Lessons from the environmental impact assessments of the TGP are: (1) hydro project planning needs to take place at a broader scale, and a strategic environmental assessment at a broader scale is necessary in advance of individual environmental impact assessments; (2) national policy and planning adjustments need to react quickly to the impact changes of large projects; (3) long-term environmental monitoring systems and joint operations with other large projects in the upstream areas of a river basin should be established, and the cross-impacts of climate change on projects and possible impacts of projects on regional or local climate considered.

  6. Nuclear waste: Status of DOE's nuclear waste site characterization activities

    International Nuclear Information System (INIS)

    1987-01-01

    Three potential nuclear waste repository sites have been selected to carry out characterization activities-the detailed geological testing to determine the suitability of each site as a repository. The sites are Hanford in south-central Washington State, Yucca Mountain in southern Nevada, and Deaf Smith in the Texas Panhandle. Two key issues affecting the total program are the estimations of the site characterization completion data and costs and DOE's relationship with the Nuclear Regulatory Commission which has been limited and its relations with affected states and Indian tribes which continue to be difficult

  7. Klipperaas study site. Scope of activities and main results

    International Nuclear Information System (INIS)

    Ahlbom, K.; Andersson, J.E.; Andersson, Peter; Ittner, T.; Tiren, S.; Ljunggren, C.

    1992-09-01

    During the period from 1977 - 1986 SKB (Swedish Nuclear Fuel and Waste Management Co.) performed surface and borehole investigations of 14 study sites for the purpose of assessing their suitability for a repository of spent nuclear fuel. The next phase in the SKB site selection rpogramme will be to perform detailed characterisation, including characterization from shafts and/or tunnels, of two or three sites. The detailed investigations will continue over several years to provide all the data needed for a licensing application to build a repository. Such an application is foreseen to be given to the authorities around the year 2003. It is presently not clear if any of the study sites will be selected as a site for detailed characterization. Other sites with geological and/or socio-economical characteristics judged more favorable may very well be the ones selected. However, as a part of the background documentation needed for the site selection studies to come, summary reports will be prepared for most study sites. These reports will include scope of activities, main results, uncertainties and need of complementary investigations. This report concern the Klipperaas study site. The main topics are the scope of activities, geologic model, geohydrological model, groundwater chemistry, assessment of solute transport, and rock mechanics

  8. Spatial bedrock erosion distribution in a natural gorge

    Science.gov (United States)

    Beer, A. R.; Turowski, J. M.; Kirchner, J. W.

    2015-12-01

    Quantitative analysis of morphological evolution both in terrestrial and planetary landscapes is of increasing interest in the geosciences. In mountainous regions, bedrock channel formation as a consequence of the interaction of uplift and erosion processes is fundamental for the entire surface evolution. Hence, the accurate description of bedrock channel development is important for landscape modelling. To verify existing concepts developed in the lab and to analyse how in situ channel erosion rates depend on the interrelations of discharge, sediment transport and topography, there is a need of highly resolved topographic field data. We analyse bedrock erosion over two years in a bedrock gorge downstream of the Gorner glacier above the town of Zermatt, Switzerland. At the study site, the Gornera stream cuts through a roche moutonnée in serpentine rock of 25m length, 5m width and 8m depth. We surveyed bedrock erosion rates using repeat terrestrial laser scanning (TLS) with an average point spacing of 5mm. Bedrock erosion rates in direction of the individual surface normals were studied directly on the scanned point clouds applying the M3C2 algorithm (Lague et al., 2013, ISPRS). The surveyed erosion patterns were compared to a simple stream erosivity visualisation obtained from painted bedrock sections at the study location. Spatially distributed erosion rates on bedrock surfaces based on millions of scan points allow deduction of millimeter-scale mean annual values of lateral erosion, incision and downstream erosion on protruding streambed surfaces. The erosion rate on a specific surface point is shown to depend on the position of this surface point in the channel's cross section, its height above the streambed and its spatial orientation to the streamflow. Abrasion by impacting bedload was likely the spatially dominant erosion process, as confirmed by the observed patterns along the painted bedrock sections. However, a single plucking event accounted for the half

  9. STUDIES ON LIGULARIA SIBIRICA (L. CASS. IN ITS SOUTHERN POINT IN ROMANIA, BRUSTURETULUI GORGES, ARGEŞ COUNTY

    Directory of Open Access Journals (Sweden)

    Andreea Natalia Matei

    2015-12-01

    Full Text Available The community importance species, Ligularia sibirica (L. Cass. it is located in its southern point in Romania, in Brusturetului Gorges in Arges County. In NATURA 2000 habitat, 3220 Alpine rivers and herbaceous vegetation along their banks, it is present the species of community importance Ligularia sibirica (L. Cass. in the plant association: Carici remotae-Calthetum laethae Coldea (1972 1978 ligularietosum sibiricae Alexiu et Stancu 2003. Habitat description and qualitative and quantitative analysis of association flora, it has an important role in establishing the conservation status of relict species Ligularia sibirica (L. Cass. Through obtained results, the present paper is contributing to the existent information related to the studied species and to the presentation of its preservation nowadays. Ligularia sibirica (L. Cass. species require real protective measures at the site.

  10. Dashboard applications to monitor experiment activities at sites

    Energy Technology Data Exchange (ETDEWEB)

    Andreeva, Julia; Gaidioz, Benjamin; Grigoras, Costin; Kokoszkiewicz, Lukasz; Lanciotti, Elisa; Rocha, Ricardo; Saiz, Pablo; Santinelli, Roberto; Sidorova, Irina; Sciaba, Andrea [CERN, European Organization for Nuclear Research (Switzerland); Belforte, Stefano [INFN Trieste (Italy); Boehm, Max [EDS, an HP Company, Plano, TX (United States); Casajus, Adrian [Universitat de Barcelona (Spain); Flix, Josep [PIC, Port d' Informacio CientIfica, Bellaterra (Spain); Tsaregorodtsev, Andrei, E-mail: Elisa.Lanciotti@cern.c, E-mail: Pablo.Saiz@cern.c [CPPM Marseille (France)

    2010-04-01

    In the framework of a distributed computing environment, such as WLCG, monitoring has a key role in order to keep under control activities going on in sites located in different countries and involving people based in many different sites. To be able to cope with such a large scale heterogeneous infrastructure, it is necessary to have monitoring tools providing a complete and reliable view of the overall performance of the sites. Moreover, the structure of a monitoring system critically depends on the object to monitor and on the users it is addressed to. In this article we will describe two different monitoring systems both aimed to monitor activities and services provided in the WLCG framework, but designed in order to meet the requirements of different users: Site Status Board has an overall view of the services available in all the sites supporting an experiment, whereas Siteview provides a complete view of all the activities going on at a site, for all the experiments supported by the site.

  11. Dashboard applications to monitor experiment activities at sites

    International Nuclear Information System (INIS)

    Andreeva, Julia; Gaidioz, Benjamin; Grigoras, Costin; Kokoszkiewicz, Lukasz; Lanciotti, Elisa; Rocha, Ricardo; Saiz, Pablo; Santinelli, Roberto; Sidorova, Irina; Sciaba, Andrea; Belforte, Stefano; Boehm, Max; Casajus, Adrian; Flix, Josep; Tsaregorodtsev, Andrei

    2010-01-01

    In the framework of a distributed computing environment, such as WLCG, monitoring has a key role in order to keep under control activities going on in sites located in different countries and involving people based in many different sites. To be able to cope with such a large scale heterogeneous infrastructure, it is necessary to have monitoring tools providing a complete and reliable view of the overall performance of the sites. Moreover, the structure of a monitoring system critically depends on the object to monitor and on the users it is addressed to. In this article we will describe two different monitoring systems both aimed to monitor activities and services provided in the WLCG framework, but designed in order to meet the requirements of different users: Site Status Board has an overall view of the services available in all the sites supporting an experiment, whereas Siteview provides a complete view of all the activities going on at a site, for all the experiments supported by the site.

  12. Active sites environmental monitoring program FY 1997 annual report

    International Nuclear Information System (INIS)

    Morrissey, C.M.; Marshall, D.S.; Cunningham, G.R.

    1998-03-01

    This report summarizes the activities conducted by the Active Sites Environmental Monitoring Program (ASEMP) from October 1996 through September 1997. The purpose of the program is to provide early detection and performance monitoring at active low-level waste (LLW) disposal sites in Solid Waste Storage Area (SWSA) 6 and transuranic (TRU) waste storage sites in SWSA 5 North. This report continues a series of annual and semiannual reports that present the results of ASEMP monitoring activities. This report details monitoring results for fiscal year (FY) 1997 from SWSA 6, including the Interim Waste Management Facility (IWMF) and the Hillcut Disposal Test Facility (HDTF), and (2) TRU-waste storage areas in SWSA 5 N. This report presents a summary of the methodology used to gather data for each major area along with the FY 1997 results. Figures referenced in the text are found in Appendix A and data tables are presented in Appendix B

  13. Gideaa study site. Scope of activities and main results

    International Nuclear Information System (INIS)

    Ahlbom, K.; Andersson, J.E.; Nordqvist, R.; Ljunggren, C.; Tiren, S.; Voss, C.

    1991-10-01

    During the period from 1977-1986 SKB (Swedish Nuclear Fuel and Waste Management Co) performed surface and borehole investigations of 14 study sites for the purpose of assessing their suitability for a repository of spent nuclear fuel. The next phase in the SKB site selection programme will be to perform detailed characterization, including characterization from shafts and/or tunnels, of two or three sites. The detailed investigations will continue over several years to provide all the data needed for a licensing application to build a repository. Such an application is foreseen to be given to the authorities around the year 2003. It is presently not clear if anyone of the study sites will be selected as a site for detailed characterization. Other site with geological and/or socio-economical characteristics judged more favourable may very well be the ones selected. However, as a part of the background documentation needed for the site selection studies to come, summary reports will be prepared for most study sites. These reports will include scope of activities, main results, uncertainties and need of complementary investigations. This report concerns the Gideaa study site. (au)

  14. Kamlunge study site. Scope of activities and main results

    International Nuclear Information System (INIS)

    Ahlbom, K.; Andersson, J.E.; Andersson, P.; Ittner, T.; Tiren, S.; Ljunggren, C.

    1992-05-01

    During the period from 1977-1986 SKB (Swedish nuclear Fuel and Waste Management Co.) performed surface and borehole investigations of 14 study sites for the purpose of assessing their suitability for a repository of spent nuclear fuel. The next phase in the SKB site selection programme will be to perform detailed characterization, including characterization from shafts and/or tunnels, of two or three sites. The detailed investigations will continue over several years to provide all the data needed for a licensing application to build a repository. Such an application is foreseen to be given to the authorities around the year 2003. It is presently not clear if anyone of the study sites will be selected as a site for detailed characterization. Other sites with geological and/or socio-economical characteristics judged more favourable may very well be selected. However, as a part of the background documentation needed for the site selection studies to come, summary reports will be prepared for most study sites. These reports will include scope of activities, main results, uncertainties and need of complementary investigations. This report concerns the Kamlunge study site. (79 refs.) (au)

  15. Fjaellveden study site. Scope of activities and main results

    International Nuclear Information System (INIS)

    Ahlbom, K.; Andersson, J.E.; Nordqvist, R.; Ljunggren, C.; Tiren, S.; Voss, C.

    1991-10-01

    During the period from 1977-1986 SKB (Swedish Nuclear Fuel and Waste Management CO) performed surface and borehole investigations of 14 study sites for the purpose of assessing their suitability for a repository of spent nuclear fuel. The next phase in the SKB site selection programme will be to perform detailed characterization, including characterization from shafts and/or tunnels, of two or three sites. The detailed investigations will continue over several years to provide all the data needed for a licensing application to build repository. Such an application is foreseen to be given to the authorities around the year 2003. It is presently not clear if anyone of the study sites will be selected as a site for detailed characterization. Other sites with geological and/or socio-economical characteristics judged more favourable may very well be the ones selected. However, as a part of the background documentation needed for the site selection studies to come, summary reports will be prepared for most study sites. These reports will include scope of activities, main results, uncertainties and need for complementary investigations. This report concerns the Fjaellveden study site. (au)

  16. Landslides in the western Columbia Gorge, Skamania County, Washington

    Science.gov (United States)

    Pierson, Thomas C.; Evarts, Russell C.; Bard, Joseph A.

    2016-11-04

    SummaryRecent light detection and ranging (lidar) imagery has allowed us to identify and map a large number of previously unrecognized landslides, or slides, in heavily forested terrain in the western Columbia Gorge, Skamania County, Washington, and it has revealed that the few previously recognized areas of instability are actually composites of multiple smaller landslides. The high resolution of the imagery further reveals that landslides in the map area have complex movement histories and span a wide range of relative ages. Movement histories are inferred from relative landslide locations and crosscutting relations of surface features. Estimated age ranges are based on (1) limited absolute dating; (2) relative fineness of landscape surface textures, calibrated by comparison with surfaces of currently active and dated landslides as interpreted from interferometric synthetic aperture radar (InSAR), global positioning system (GPS), and historical records; (3) sharpness and steepness of larger-scale surface morphologic features, calibrated by comparison with similar dated features in other regions; (4) degree of surface erosion; and (5) evidence of erosion or deposition by late Pleistocene (15–22 ka) Missoula floods at or below 200 m altitude. The relative age categories are recent (0 to ~1,000 years old), intermediate-age (~1,000 to ~15,000 years old), and old (>~15,000 years old). Within the 221.5 km2 map area, we identified 215 discrete landslides, covering 140.9 km2 (64 percent of the map area). At least 12 of the recent landslides are currently moving or have moved within the last two decades. Mapping for this study expanded the area of previously recognized unstable terrain by 56 percent. Landslide geometries suggest that more than half (62 percent) of these slope failures are translational landslides or composite landslides with translational elements, with failure occurring along gently sloping bedding planes in zones of deeply weathered, locally clay rich

  17. Active chemisorption sites in functionalized ionic liquids for carbon capture.

    Science.gov (United States)

    Cui, Guokai; Wang, Jianji; Zhang, Suojiang

    2016-07-25

    Development of novel technologies for the efficient and reversible capture of CO2 is highly desired. In the last decade, CO2 capture using ionic liquids has attracted intensive attention from both academia and industry, and has been recognized as a very promising technology. Recently, a new approach has been developed for highly efficient capture of CO2 by site-containing ionic liquids through chemical interaction. This perspective review focuses on the recent advances in the chemical absorption of CO2 using site-containing ionic liquids, such as amino-based ionic liquids, azolate ionic liquids, phenolate ionic liquids, dual-functionalized ionic liquids, pyridine-containing ionic liquids and so on. Other site-containing liquid absorbents such as amine-based solutions, switchable solvents, and functionalized ionic liquid-amine blends are also investigated. Strategies have been discussed for how to activate the existent reactive sites and develop novel reactive sites by physical and chemical methods to enhance CO2 absorption capacity and reduce absorption enthalpy. The carbon capture mechanisms of these site-containing liquid absorbents are also presented. Particular attention has been paid to the latest progress in CO2 capture in multiple-site interactions by amino-free anion-functionalized ionic liquids. In the last section, future directions and prospects for carbon capture by site-containing ionic liquids are outlined.

  18. Active Sites Environmental Monitoring Program: Mid-FY 1991 report

    Energy Technology Data Exchange (ETDEWEB)

    Ashwood, T.L.; Wickliff, D.S.; Morrissey, C.M.

    1991-10-01

    This report summarizes the activities of the Active Sites Environmental Monitoring Program (ASEMP) from October 1990 through March 1991. The ASEMP was established in 1989 by Solid Waste Operations and the Environmental Sciences Division to provide early detection and performance monitoring at active low-level radioactive waste (LLW) disposal sites in Solid Waste Storage Area (SWSA) 6 and transuranic (TRU) waste storage sites in SWSA 5 as required by chapters II and III of US Department of Energy Order 5820.2A. Monitoring results continue to demonstrate the no LLW is being leached from the storage vaults on the tumulus pads. Loading of vaults on Tumulus II began during this reporting period and 115 vaults had been loaded by the end of March 1991.

  19. Guidelines for Including Gorges in the Tourist Offer of the Apuseni Mountains

    Directory of Open Access Journals (Sweden)

    GABRIELA COCEAN

    2014-12-01

    Full Text Available In any tourism development plans, the starting point ought to be the accurate assessment of the tourism resources that can be efficiently put to use. When evaluating the potential for the tourism development of karstic gorges, the most objective criteria were applied: the attractiveness of each gorge, the location and the competitive forms of tourism that can be developed in the area. As a result, we have identified four categories of gorges: primary, secondary, complementary gorges and those of less relevance for the tourism phenomenon. The next step that would have a direct impact on the development of tourism around gorges (building of infrastructure, access roads, etc. is to consolidate and revitalize the brand of each gorge in order to define it as a unique tourist destination. Effective branding of gorges starts with establishing the unique selling proposition, consisting of those attributes of high specificity that determine certain dominant types of tourism. It is only after identifying the strengths that build up their own tourist brands that one can consider including these landmarks in thematic routes, creating synergy and adding value to the whole gorge ensemble.

  20. Geological constraints on cave development in the plateau-gorge karst of South China (Wulong, Chongqing)

    Science.gov (United States)

    Szczygieł, Jacek; Golicz, Mateusz; Hercman, Helena; Lynch, Erin

    2018-03-01

    The Houping Tiankeng cluster is a part of the South China Karst UNESCO World Natural Heritage Site. Within the distinctive Wulong plateau-gorge karst, > 200 km of cave passages have been documented to date. This paper focuses on detailed tectonic and morphological research on the Luo Shui Kong cave, enriched with U-series dating of speleothems and complemented by morphometric analysis of the San Wang Dong and Er Wang Dong caves. All of these caves exhibit three regional levels of cave development: 1) 1040-1020 m a.s.l.; 2) 900-840 m a.s.l.; and 3) 740-660 m a.s.l. The Houping Tiankeng area is a carbonate rock sequence several hundred meters thick, overlain by the less soluble Lower Ordovician strata, limiting recharge points to faults exposing underlying easily soluble formations. This leads to the domination of concentrated, high-volume inflow and thus results in caves of large volume in the plateau-gorge karst. Shafts connecting the surface with cave passages located underneath formed along faults, changing the hydrogeological pattern through karst water capture and remodeling of existing conduits, albeit mainly by increasing their overall dimensions rather than by deepening them. The most favorable structures for cave-level development are two sets of joints conjugated with gently inclined bedding. Since these joints are characterized by a small vertical extent, downward development is limited. Hence, most of the passages are wide but not deep canyons and typical of a water-table cave pattern. Places where the fault plane is eroded from the surface and where, at the same time, an underneath cave chamber ceiling expands upwards are particularly predisposed to the formation of a tiankeng.

  1. The nature of the active site in heterogeneous metal catalysis

    DEFF Research Database (Denmark)

    Nørskov, Jens Kehlet; Bligaard, Thomas; Larsen, Britt Hvolbæk

    2008-01-01

    This tutorial review, of relevance for the surface science and heterogeneous catalysis communities, provides a molecular-level discussion of the nature of the active sites in metal catalysis. Fundamental concepts such as "Bronsted-Evans-Polanyi relations'' and "volcano curves'' are introduced...

  2. Active Sites Environmental Monitoring Program: FY 1990 annual report

    International Nuclear Information System (INIS)

    Wickliff, D.S.; Morrissey, C.M.; Ashwood, T.L.

    1991-10-01

    Chapter 3 of US Department of Energy (DOE) Order 5820.2A (DOE 1988) sets forth requirements for environmental monitoring of active low-level waste (LLW) disposal sites. Active sites are defined as those LLW facilities that were in use on or after the date of the order (September 1988). The transuranic (TRU) waste storage areas in Solid Waste Storage Area (SWSA) 5 North are covered by Chap. 2 of the order. In both chapters, monitoring is required to provide for early warning of leaks before those leaks pose a threat to human health or the environment. Chapter 3 also requires that monitoring be conducted to evaluate the short- and long-term performance of LLW disposal facilities. In accordance with this order, the Solid Waste Operations Department at Oak Ridge National Laboratory (ORNL) has established an Active Sites Environmental Monitoring Program (ASEMP) that is implemented by staff of the Environmental Sciences Division (ESD) at ORNL. This report summarizes data from ASEMP monitoring activities for the final 6 months of FY 1990. A brief summary of the monitoring methodology for each site is presented also

  3. Leachate characterization of active and closed dump sites in Port ...

    African Journals Online (AJOL)

    This study characterizes the leachate quality of both active and closed dump sites in Port Harcourt City. Leachates were sampled from the base of the dum psites and analysed, pH, dissolved oxygen (DO), electrical conductivity and total dissolved solids were determined on the samples in-situ. While chloride, sulphate ...

  4. Energy transfer at the active sites of heme proteins

    International Nuclear Information System (INIS)

    Dlott, D.D.; Hill, J.R.

    1995-01-01

    Experiments using a picosecond pump-probe apparatus at the Picosecond Free-electron Laser Center at Stanford University, were performed to investigate the relaxation of carbon monoxide bound to the active sites of heme proteins. The significance of these experiments is two-fold: (1) they provide detailed information about molecular dynamics occurring at the active sites of proteins; and (2) they provide insight into the nature of vibrational relaxation processes in condensed matter. Molecular engineering is used to construct various molecular systems which are studied with the FEL. We have studied native proteins, mainly myoglobin obtained from different species, mutant proteins produced by genetic engineering using recombinant DNA techniques, and a variety of model systems which mimic the structures of the active sites of native proteins, which are produced using molecular synthesis. Use of these different systems permits us to investigate how specific molecular structural changes affect dynamical processes occurring at the active sites. This research provides insight into the problems of how different species needs are fulfilled by heme proteins which have greatly different functionality, which is induced by rather small structural changes

  5. Ecosystem health evaluation system of the water-fluctuating zone in the Three Gorges Area

    Institute of Scientific and Technical Information of China (English)

    WANG Li-ao; YUAN Hui; ZHANG Yan-hui; HU Gang

    2004-01-01

    This paper discribes the definition of ecosystem health for the water-level flutuation zone of the Three Gorges Region and puts forward an evaluation system involving indicators in three groups: 1) structural indicators comprise slope, biodiversity,environmental capacity, stability, restoration ability and damage situation; 2) functional indicators including probability of geological hazard, erosion rate, habitat rate, land use intension and days of tourist season; 3) environmental indicatiors made up of population quality, potential intension of human, ground water quality, ambient air quality, wastewater treatment rate, pesticide use rate, fertilizer use rate, environmental management and public participation. In the design of the system, the subject zone is regarded as the type similar to wetland and the impacts of human activities on the zone are attached great importance to.

  6. Direct instrumental identification of catalytically active surface sites

    Science.gov (United States)

    Pfisterer, Jonas H. K.; Liang, Yunchang; Schneider, Oliver; Bandarenka, Aliaksandr S.

    2017-09-01

    The activity of heterogeneous catalysts—which are involved in some 80 per cent of processes in the chemical and energy industries—is determined by the electronic structure of specific surface sites that offer optimal binding of reaction intermediates. Directly identifying and monitoring these sites during a reaction should therefore provide insight that might aid the targeted development of heterogeneous catalysts and electrocatalysts (those that participate in electrochemical reactions) for practical applications. The invention of the scanning tunnelling microscope (STM) and the electrochemical STM promised to deliver such imaging capabilities, and both have indeed contributed greatly to our atomistic understanding of heterogeneous catalysis. But although the STM has been used to probe and initiate surface reactions, and has even enabled local measurements of reactivity in some systems, it is not generally thought to be suited to the direct identification of catalytically active surface sites under reaction conditions. Here we demonstrate, however, that common STMs can readily map the catalytic activity of surfaces with high spatial resolution: we show that by monitoring relative changes in the tunnelling current noise, active sites can be distinguished in an almost quantitative fashion according to their ability to catalyse the hydrogen-evolution reaction or the oxygen-reduction reaction. These data allow us to evaluate directly the importance and relative contribution to overall catalyst activity of different defects and sites at the boundaries between two materials. With its ability to deliver such information and its ready applicability to different systems, we anticipate that our method will aid the rational design of heterogeneous catalysts.

  7. Role of active site rigidity in activity: MD simulation and fluorescence study on a lipase mutant.

    Directory of Open Access Journals (Sweden)

    Md Zahid Kamal

    Full Text Available Relationship between stability and activity of enzymes is maintained by underlying conformational flexibility. In thermophilic enzymes, a decrease in flexibility causes low enzyme activity while in less stable proteins such as mesophiles and psychrophiles, an increase in flexibility is associated with enhanced enzyme activity. Recently, we identified a mutant of a lipase whose stability and activity were enhanced simultaneously. In this work, we probed the conformational dynamics of the mutant and the wild type lipase, particularly flexibility of their active site using molecular dynamic simulations and time-resolved fluorescence techniques. In contrast to the earlier observations, our data show that active site of the mutant is more rigid than wild type enzyme. Further investigation suggests that this lipase needs minimal reorganization/flexibility of active site residues during its catalytic cycle. Molecular dynamic simulations suggest that catalytically competent active site geometry of the mutant is relatively more preserved than wild type lipase, which might have led to its higher enzyme activity. Our study implies that widely accepted positive correlation between conformation flexibility and enzyme activity need not be stringent and draws attention to the possibility that high enzyme activity can still be accomplished in a rigid active site and stable protein structures. This finding has a significant implication towards better understanding of involvement of dynamic motions in enzyme catalysis and enzyme engineering through mutations in active site.

  8. Use of aerial videography to evaluate the effects of Flaming Gorge Dam operations on natural resources of the Green River

    International Nuclear Information System (INIS)

    Snider, M.A.; Hayse, J.W.; Hlohowskyj, I.; LaGory, K.E.; Greaney, M.M.; Kuiper, J.A.; Van Lonkhuyzen, R.A.

    1993-01-01

    Peaking hydropower operations can profoundly alter natural stream flow and thereby affect the natural resources dependent on these flows. In this paper, we describe how aerial videography was used to collect environmental data and evaluate impacts of hydropower operations at Flaming Gorge Dam on natural resources of the Green River. An airborne multispectral video/radiometer remote sensing system was used to collect resource data under four different flow conditions from seven sites (each about one mile in length) located downstream from the dam. Releases from Flaming Gorge Dam during data collection ranged from approximately 800 to 4,000 cubic feet/sec (cfs), spanning most of the normal operating range for this facility. For each site a series of contiguous, non-overlapping images was prepared from the videotapes and used to quantify surface water area, backwater habitats, and areas of riparian vegetation under varying flow conditions. From this information, relationships between flow and habitat parameters were developed and used in conjunction with hydrologic modeling and ecological information to evaluate impacts of various modes of operation

  9. The power plant among Three Gorges; Kraftstasjonen blant Tre kloefter

    Energy Technology Data Exchange (ETDEWEB)

    Stensvold, Tore

    2003-07-01

    In 2009 the Three Gorges power station on the Yangtze River in China will be completed, with 26 turbines that together will produce 84.60 TWh/year. In this article a Norwegian expert describes his experience from a tourist visit, approaching the plant onboard a cruise ship. In addition to giving the main technical data he comments on peoples' resistance against being transferred, on scepticism and fear of a dam break, on the shortcomings of the power grid and on the not very extensive Norwegian contribution to the world's largest power plant.

  10. Statistical evaluation of the effects of fall and winter flows on the spring condition of rainbow and brown trout in the green river downstream of Flaming Gorge Dam.

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, A. K.; LaGory, K. E.; Hayse, J. W.; Environmental Science Division

    2009-01-09

    Flaming Gorge Dam, a hydroelectric facility operated by the Bureau of Reclamation (Reclamation), is located on the Green River in Daggett County, northeastern Utah. In recent years, single peak releases each day or steady flows have been the operational pattern during the winter period. A double-peak pattern (two flow peaks each day) was implemented during the winter of 2006-2007 by Reclamation. Because there is no recent history of double-peaking at Flaming Gorge Dam, the potential effects of double-peaking operations on the body condition of trout in the dam's tailwater are not known. A study plan was developed that identified research activities to evaluate potential effects from double-peaking operations during winter months. Along with other tasks, the study plan identified the need to conduct a statistical analysis of existing data on trout condition and macroinvertebrate abundance to evaluate potential effects of hydropower operations. This report presents the results of this analysis. We analyzed historical data to (1) describe temporal patterns and relationships among flows, benthic macroinvertebrate abundance, and condition of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in the tailwaters of Flaming Gorge Dam and (2) to evaluate the degree to which flow characteristics (i.e., flow volumes and flow variability) and benthic macroinvertebrate abundance affect the condition of trout in this area. This information, together with further analyses of size-stratified trout data, may also serve as baseline data to which the effects of potential future double-peaking flows can be compared. The condition (length, weight and/or relative weight) of rainbow trout (Oncorhynchus mykiss) at two sites in the Green River downstream of Flaming Gorge Dam (Tailrace and Little Hole) and weight of brown trout (Salmo trutta) at the Little Hole site has been decreasing since 1990 while the abundance of brown trout has been increasing at the two sites. At

  11. Statistical evaluation of the effects of fall and winter flows on the spring condition of rainbow and brown trout in the Green River downstream of Flaming Gorge Dam

    International Nuclear Information System (INIS)

    Magnusson, A. K.; LaGory, K. E.; Hayse, J. W.

    2009-01-01

    Flaming Gorge Dam, a hydroelectric facility operated by the Bureau of Reclamation (Reclamation), is located on the Green River in Daggett County, northeastern Utah. In recent years, single peak releases each day or steady flows have been the operational pattern during the winter period. A double-peak pattern (two flow peaks each day) was implemented during the winter of 2006-2007 by Reclamation. Because there is no recent history of double-peaking at Flaming Gorge Dam, the potential effects of double-peaking operations on the body condition of trout in the dam's tailwater are not known. A study plan was developed that identified research activities to evaluate potential effects from double-peaking operations during winter months. Along with other tasks, the study plan identified the need to conduct a statistical analysis of existing data on trout condition and macroinvertebrate abundance to evaluate potential effects of hydropower operations. This report presents the results of this analysis. We analyzed historical data to (1) describe temporal patterns and relationships among flows, benthic macroinvertebrate abundance, and condition of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in the tailwaters of Flaming Gorge Dam and (2) to evaluate the degree to which flow characteristics (i.e., flow volumes and flow variability) and benthic macroinvertebrate abundance affect the condition of trout in this area. This information, together with further analyses of size-stratified trout data, may also serve as baseline data to which the effects of potential future double-peaking flows can be compared. The condition (length, weight and/or relative weight) of rainbow trout (Oncorhynchus mykiss) at two sites in the Green River downstream of Flaming Gorge Dam (Tailrace and Little Hole) and weight of brown trout (Salmo trutta) at the Little Hole site has been decreasing since 1990 while the abundance of brown trout has been increasing at the two sites. At the

  12. Mapping the active site of vaccinia virus RNA triphosphatase

    International Nuclear Information System (INIS)

    Gong Chunling; Shuman, Stewart

    2003-01-01

    The RNA triphosphatase component of vaccinia virus mRNA capping enzyme (the product of the viral D1 gene) belongs to a family of metal-dependent phosphohydrolases that includes the RNA triphosphatases of fungi, protozoa, Chlorella virus, and baculoviruses. The family is defined by two glutamate-containing motifs (A and C) that form the metal-binding site. Most of the family members resemble the fungal and Chlorella virus enzymes, which have a complex active site located within the hydrophilic interior of a topologically closed eight-stranded β barrel (the so-called ''triphosphate tunnel''). Here we queried whether vaccinia virus capping enzyme is a member of the tunnel subfamily, via mutational mapping of amino acids required for vaccinia triphosphatase activity. We identified four new essential side chains in vaccinia D1 via alanine scanning and illuminated structure-activity relationships by conservative substitutions. Our results, together with previous mutational data, highlight a constellation of six acidic and three basic amino acids that likely compose the vaccinia triphosphatase active site (Glu37, Glu39, Arg77, Lys107, Glu126, Asp159, Lys161, Glu192, and Glu194). These nine essential residues are conserved in all vertebrate and invertebrate poxvirus RNA capping enzymes. We discerned no pattern of clustering of the catalytic residues of the poxvirus triphosphatase that would suggest structural similarity to the tunnel proteins (exclusive of motifs A and C). We infer that the poxvirus triphosphatases are a distinct lineage within the metal-dependent RNA triphosphatase family. Their unique active site, which is completely different from that of the host cell's capping enzyme, recommends the poxvirus RNA triphosphatase as a molecular target for antipoxviral drug discovery

  13. Decommissioning and decontamination activity, Gnome Site, Eddy County, New Mexico

    International Nuclear Information System (INIS)

    1978-10-01

    The purpose of this assessment is to present a brief description of the proposed activity and its potential impacts on the environment. This assessment will constitute an evaluation as to whether or not a formal Environmental Statement need be prepared. As background to the proposed activity, Project Gnome was an underground nuclear test conducted in December 1961 as part of the PLOWSHARE Program. The project site is located about 25 miles southeast of Carlsbad, New Mexico. By means of an excavated shaft and tunnel, a 3-kiloton nuclear explosive was emplaced and detonated in a salt bed about 1200 feet below the surface. The uncontaminated rock and salt muck from the original excavation and subsequent contaminated muck and minor construction debris from reentry activities into the nuclear cavity is commingled and stored in a pile near the Gnome/Coach Shaft. Other areas on the site are known to have been contaminated. In 1969, a program was conducted to cleanup and dispose of all surface contamination to whatever depth it occurred in excess of 0.1 mR/hr. Contaminated materials and soil were collected and disposed into the Gnome shaft, which was filled and sealed. Since then, NV has proposed to DOE/HQ much lower criteria for residual radioactive contamination for the Gnome Site. These proposed criteria were to collect and dispose of surficial materials which contain more than 2 x 10 -5 microcuries per gram of soil for beta/gamma emitters and 3 x 10 -2 microcuries per milliliter of tritium in soil moisture. According to the latest reconnaissance in 1972, low concentrations of Cs-137, Sr-90 and tritium were present at various locations on the site in excess of these proposed guidelines. Other operational areas within the site are suspected of containing radioactive contamination in much lesser volume, which are to be determined by careful probing and monitoring, as described in the next section

  14. Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge.

    Science.gov (United States)

    Kimura, Yuki

    2002-09-01

    The lithic analysis of the Bed I and II assemblages from Olduvai Gorge reveals both static and dynamic time trends in early hominids' technology from 1.8 to 1.2 m.y.a. The Bed I Oldowan (1.87-1.75 m.y.a.) is characterized by the least effort strategy in terms of raw material exploitation and tool production. The inclusion of new raw material, chert, for toolmaking in the following Developed Oldowan A (DOA, 1.65-1.53 m.y.a.) facilitated more distinctive and variable flaking strategies depending on the kind of raw materials. The unique characters of DOA are explainable by this raw material factor, rather than technological development of hominids. The disappearance of chert in the subsequent Developed Oldowan B and Acheulian (1.53-1.2 m.y.a.) necessitated a shift in tool production strategy more similar to that of Bed I Oldowan than DOA. However, the evidence suggests that Bed II hominids might have been more skillful toolmakers, intensive tool-users, and engaged in more active transport of stone tools than the Bed I predecessors. Koobi Fora hominids maintained a more static tool-using behavior than their Olduvai counterparts due mainly to a stable supply of raw materials. They differed from Olduvai hominids in terms of less battering of cores, consistent transport behavior, and few productions of side-struck flakes, indicating a regional variation of toolmaking and using practice. However, they shared with Olduvai hominids a temporal trend toward the production of larger flakes from larger cores after 1.6 m.y.a. Increased intake of animal resources and the expansion of ranging area of Homo ergaster would have led to the development of technological organization. Technological changes in the Oldowan industry are attested at Olduvai Gorge, Koobi Fora, and Sterkfontein, suggesting that it was a pan-African synchronous phenomenon, beginning at 1.5 m.y.a.

  15. Methodology for contaminated sites of military activity territories restoration

    International Nuclear Information System (INIS)

    Khrushchov, D. P.; Yushchenko, Yu. V.; Shekhunova, S. B.

    2002-01-01

    Major part of Eastern Europe countries meet environmental problems related to sites of military activity. Major part of these sites is characterised with degradation of natural landscapes and contamination of geological environment with toxic and hazardous waste representing actual and potential danger for population and environment. Actual danger is caused with localisation of toxic waste, hazardous materials and waste which are preventing normal land use. Potential danger is related to successive dispersion of contamination in biosphere as well as origin of new derivatives and products having toxic and hazardous properties. The list of such sites and objects comprises bases of land, air and naval forces. These objects include a network of infrastructures: storages of fuels and lubricants (surface, underground), filling stations, pipe lines, reparation stations, garages, decontamination stations, underground storages of different purposes, depots (for ammunition, chemical products), hospitals, constructions, firing grounds (tank, artillery, aircraft bombing etc.) and waste disposal sites. Special programs aimed at military industries and bases contaminated sites remediation have been carrying out in developed countries (USA, United Kingdom, Germany etc.). This experience was used in the frames of joint programs having been founded in several countries of Central and Eastern Europe (Chesh Republic, Slovakia, Lithuania etc.). (author)

  16. Active Sites Environmental Monitoring Program. FY 1993: Annual report

    International Nuclear Information System (INIS)

    Morrissey, C.M.; Ashwood, T.L.; Hicks, D.S.; Marsh, J.D.

    1994-08-01

    This report continues a series of annual and semiannual reports that present the results of the Active Sites Environmental Monitoring Program (ASEMP) monitoring activities. The report details monitoring data for fiscal year (FY) 1993 and is divided into three major areas: SWSA 6 [including tumulus pads, Interim Waste Management Facility (IWMF), and other sites], the low-level Liquid-Waste Solidification Project (LWSP), and TRU-waste storage facilities in SWSA 5 N. The detailed monitoring methodology is described in the second revision of the ASEMP program plan. This report also presents a summary of the methodology used to gather data for each major area along with the results obtained during FY 1993

  17. Active sites in char gasification: Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Wojtowicz, M.; Lilly, W.D.; Perkins, M.T.; Hradil, G.; Calo, J.M.; Suuberg, E.M.

    1987-09-01

    Among the key variables in the design of gasifiers and combustors is the reactivity of the chars which must be gasified or combusted. Significant loss of unburned char is unacceptable in virtually any process; the provision of sufficient residence time for complete conversion is essential. A very wide range of reactivities are observed, depending upon the nature of the char in a process. The current work focuses on furthering the understanding of gasification reactivities of chars. It has been well established that the reactivity of char to gasification generally depends upon three principal factors: (1) the concentration of ''active sites'' in the char; (2) mass transfer within the char; and (3) the type and concentration of catalytic impurities in the char. The present study primarily addresses the first factor. The subject of this research is the origin, nature, and fate of active sites in chars derived from parent hydrocarbons with coal-like structure. The nature and number of the active sites and their reactivity towards oxygen are examined in ''model'' chars derived from phenol-formaldehyde type resins. How the active sites are lost by the process of thermal annealing during heat treatment of chars are studied, and actual rate for the annealing process is derived. Since intrinsic char reactivities are of primary interest in the present study, a fair amount of attention was given to the model char synthesis and handling so that the effect of catalytic impurities and oxygen-containing functional groups in the chemical structure of the material were minimized, if not completely eliminated. The project would not be considered complete without comparing characteristic features of synthetic chars with kinetic behavior exhibited by natural chars, including coal chars.

  18. Delta Learning Rule for the Active Sites Model

    OpenAIRE

    Lingashetty, Krishna Chaithanya

    2010-01-01

    This paper reports the results on methods of comparing the memory retrieval capacity of the Hebbian neural network which implements the B-Matrix approach, by using the Widrow-Hoff rule of learning. We then, extend the recently proposed Active Sites model by developing a delta rule to increase memory capacity. Also, this paper extends the binary neural network to a multi-level (non-binary) neural network.

  19. Exploiting Innocuous Activity for Correlating Users Across Sites

    OpenAIRE

    Goga , Oana; Lei , Howard; Parthasarathi , Sree Hari Krishnan; Friedland , Gerald; Sommer , Robin; Teixeira , Renata

    2013-01-01

    International audience; We study how potential attackers can identify accounts on different social network sites that all belong to the same user, exploiting only innocuous activity that inherently comes with posted content. We examine three specific features on Yelp, Flickr, and Twitter: the geo-location attached to a user's posts, the timestamp of posts, and the user's writing style as captured by language models. We show that among these three features the location of posts is the most powe...

  20. Accumulation of floating microplastics behind the Three Gorges Dam.

    Science.gov (United States)

    Zhang, Kai; Gong, Wen; Lv, Jizhong; Xiong, Xiong; Wu, Chenxi

    2015-09-01

    We investigated the occurrence and distribution of microplastics in surface water from the Three Gorges Reservoir. Nine samples were collected via trawl sampling with a 112 μmmesh net. The abundances of microplastics were from 3407.7 × 10(3) to 13,617.5 × 10(3) items per square kilometer in the main stream of the Yangtze River and from 192.5 × 10(3) to 11,889.7 × 10(3) items per square kilometer in the estuarine areas of four tributaries. The abundance of microplastics in the main stream of the Yangtze River generally increased as moving closer to the Three Gorges Dam. The microplastics are made exclusively of polyethylene (PE), polypropylene (PP), and polystyrene (PS). Together with microplastics, high abundance of coal/fly ash was also observed in the surface water samples. Comparing with previously reported data, microplastics in the TGR were approximately one to three orders of magnitudes greater, suggesting reservoirs as potential hot spot for microplastic pollution. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Tiny bubbles challenge giant turbines: Three Gorges puzzle.

    Science.gov (United States)

    Li, Shengcai

    2015-10-06

    Since the birth of the first prototype of the modern reaction turbine, cavitation as conjectured by Euler in 1754 always presents as a challenge. Following his theory, the evolution of modern reaction (Francis and Kaplan) turbines has been completed by adding the final piece of the element 'draft-tube' that enables turbines to explore water energy at efficiencies of almost 100%. However, during the last two and a half centuries, with increasing unit capacity and specific speed, the problem of cavitation has been manifested and complicated by the draft-tube surges rather than being solved. Particularly, during the last 20 years, the fierce competition in the international market for extremely large turbines with compact design has encouraged the development of giant Francis turbines of 700-1000 MW. The first group (24 units) of such giant turbines of 700 MW each was installed in the Three Gorges project. Immediately after commission, a strange erosion phenomenon appeared on the guide vane of the machines that has puzzled professionals. From a multi-disciplinary analysis, this Three Gorges puzzle could reflect an unknown type of cavitation inception presumably triggered by turbulence production from the boundary-layer streak transitional process. It thus presents a fresh challenge not only to this old turbine industry, but also to the fundamental sciences.

  2. Sedimentary record and luminescence chronology of palaeoflood events along the Gold Gorge of the upper Hanjiang River, middle Yangtze River basin, China

    Science.gov (United States)

    Guo, Yongqiang; Huang, Chun Chang; Zhou, Yali; Pang, Jiangli; Zha, Xiaochun; Fan, Longjiang; Mao, Peini

    2018-05-01

    Palaeoflood slackwater deposits (SWDs) along the river banks have important implications for the reconstruction of the past hydro-climatic events. Two palaeoflood SWD beds were identified in the Holocene loess-soil sequences on the cliff river banks along the Gold Gorge of the upper Hanjiang River by field investigation and laboratory analysis. They have recorded two palaeoflood events which were dated by optically stimulated luminescence to 3.2-2.8 ka and 2.1-1.8 ka, respectively. The reliability of the ages obtained for the two events are further confirmed by the presence of archaeological remains and good regional pedostratigraphic correlation. The peak discharges of two palaeoflood events at the studied sites were estimated to be 16,560-17,930 m3/s. A correlation with the palaeoflood events identified in the other reaches shows that great floods occurred frequently during the episodes of 3200-2800 and 2000-1700 a BP along the upper Hanjiang River valley during the last 4000 years. These phases of palaeoflood events in central China are well correlated with the climatic variability identified by δ18O record in the stalagmites from the middle Yangtze River Basin and show apparent global linkages. Palaeoflood studies in a watershed scale also imply that strengthened human activities during the Shang dynasty (BCE 1600-1100) and Han dynasty (BCE206-CE265) may have caused accelerated soil erosion along the upper Hanjiang River valley.

  3. Site characterization techniques used in environmental remediation activities

    International Nuclear Information System (INIS)

    Kostelnik, K.M.

    2000-01-01

    As a result of decades of nuclear energy research, weapons production, as well as ongoing operations, a significant amount of radioactive contamination has occurred throughout the United States Department of Energy (DOE) complex. DOE facility are in the process of assessing and potentially remediating various sites according to the regulations imposed by a Federal Facility Agreement and Consent order (FFA/CO) between DOE, the state in which the facility is located, and the U.S. Environmental Protection Agency (EPA). In support of these active site remediation efforts, the DOE has devoted considerable resources towards the development of innovative site characterization techniques that support environmental restoration activities. These resources and efforts have focused on various aspects of this complex problem. Research and technology development conducted at the Idaho National Engineering and Environmental Laboratory (INEEL) has resulted in the ability and state-of-the-art equipment required to obtain real-time, densely spaced, in situ characterization data (i.e. detection, speciation, and location) of various radionuclides and contaminants. The Remedial Action Monitoring System (RAMS), developed by the INEEL, consists of enhanced sensor technology, measurement modeling and interpretation techniques, and a suite of deployment platforms which can be interchanged to directly support remedial cleanup and site verification operations. In situ characterization techniques have advanced to the point where they are being actively deployed in support of remedial operations. The INEEL has deployed its system at various DOE and international sites. The deployment of in situ characterization systems during environmental restoration operations has shown that this approach results in several significant benefits versus conventional sampling techniques. A flexible characterization system permits rapid modification to satisfy physical site conditions, available site resources

  4. Soil erosion and deposition in the new shorelines of the Three Gorges Reservoir.

    Science.gov (United States)

    Su, Xiaolei; Nilsson, Christer; Pilotto, Francesca; Liu, Songping; Shi, Shaohua; Zeng, Bo

    2017-12-01

    During the last few decades, the construction of storage reservoirs worldwide has led to the formation of many new shorelines in former upland areas. After the formation of such shorelines, a dynamic phase of soil erosion and deposition follows. We explored the factors regulating soil dynamics in the shorelines of the Three Gorges Reservoir (TGR) on the Yangtze River in China. We selected four study sites on the main stem and three on the tributaries in the upstream parts of the reservoir, and evaluated whether the sites close to the backwater tail (the point at which the river meets the reservoir) had more soil deposition than the sites far from the backwater tail. We also tested whether soil erosion differed between the main stem and the tributaries and across shorelines. We found that soil deposition in the new shorelines was higher close to the backwater tail and decreased downstream. Soil erosion was higher in the main stem than in the tributaries and higher at lower compared to higher shoreline altitudes. In the tributaries, erosion did not differ between higher and lower shoreline levels. Erosion increased with increasing fetch length, inundation duration and distance from the backwater tail, and decreased with increasing soil particle fineness. Our results provide a basis for identifying shorelines in need of restorative or protective measures. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Lions as Bone Accumulators? Paleontological and Ecological Implications of a Modern Bone Assemblage from Olduvai Gorge.

    Directory of Open Access Journals (Sweden)

    Mari Carmen Arriaza

    Full Text Available Analytic models have been developed to reconstruct early hominin behaviour, especially their subsistence patterns, revealed mainly through taphonomic analyses of archaeofaunal assemblages. Taphonomic research is used to discern which agents (carnivores, humans or both generate the bone assemblages recovered at archaeological sites. Taphonomic frameworks developed during the last decades show that the only large-sized carnivores in African biomes able to create bone assemblages are leopards and hyenas. A carnivore-made bone assemblage located in the short-grassland ecological unit of the Serengeti (within Olduvai Gorge was studied. Taphonomic analyses of this assemblage including skeletal part representation, bone density, breakage patterns and anatomical distribution of tooth marks, along with an ecological approach to the prey selection made by large carnivores of the Serengeti, were carried out. The results show that this bone assemblage may be the first lion-accumulated assemblage documented, although other carnivores (namely spotted hyenas may have also intervened through postdepositional ravaging. This first faunal assemblage potentially created by lions constitutes a new framework for neotaphonomic studies. Since lions may accumulate carcasses under exceptional circumstances, such as those documented at the site reported here, this finding may have important consequences for interpretations of early archaeological and paleontological sites, which provide key information about human evolution.

  6. Lions as Bone Accumulators? Paleontological and Ecological Implications of a Modern Bone Assemblage from Olduvai Gorge.

    Science.gov (United States)

    Arriaza, Mari Carmen; Domínguez-Rodrigo, Manuel; Yravedra, José; Baquedano, Enrique

    2016-01-01

    Analytic models have been developed to reconstruct early hominin behaviour, especially their subsistence patterns, revealed mainly through taphonomic analyses of archaeofaunal assemblages. Taphonomic research is used to discern which agents (carnivores, humans or both) generate the bone assemblages recovered at archaeological sites. Taphonomic frameworks developed during the last decades show that the only large-sized carnivores in African biomes able to create bone assemblages are leopards and hyenas. A carnivore-made bone assemblage located in the short-grassland ecological unit of the Serengeti (within Olduvai Gorge) was studied. Taphonomic analyses of this assemblage including skeletal part representation, bone density, breakage patterns and anatomical distribution of tooth marks, along with an ecological approach to the prey selection made by large carnivores of the Serengeti, were carried out. The results show that this bone assemblage may be the first lion-accumulated assemblage documented, although other carnivores (namely spotted hyenas) may have also intervened through postdepositional ravaging. This first faunal assemblage potentially created by lions constitutes a new framework for neotaphonomic studies. Since lions may accumulate carcasses under exceptional circumstances, such as those documented at the site reported here, this finding may have important consequences for interpretations of early archaeological and paleontological sites, which provide key information about human evolution.

  7. Lions as Bone Accumulators? Paleontological and Ecological Implications of a Modern Bone Assemblage from Olduvai Gorge

    Science.gov (United States)

    Arriaza, Mari Carmen; Domínguez-Rodrigo, Manuel; Yravedra, José; Baquedano, Enrique

    2016-01-01

    Analytic models have been developed to reconstruct early hominin behaviour, especially their subsistence patterns, revealed mainly through taphonomic analyses of archaeofaunal assemblages. Taphonomic research is used to discern which agents (carnivores, humans or both) generate the bone assemblages recovered at archaeological sites. Taphonomic frameworks developed during the last decades show that the only large-sized carnivores in African biomes able to create bone assemblages are leopards and hyenas. A carnivore-made bone assemblage located in the short-grassland ecological unit of the Serengeti (within Olduvai Gorge) was studied. Taphonomic analyses of this assemblage including skeletal part representation, bone density, breakage patterns and anatomical distribution of tooth marks, along with an ecological approach to the prey selection made by large carnivores of the Serengeti, were carried out. The results show that this bone assemblage may be the first lion-accumulated assemblage documented, although other carnivores (namely spotted hyenas) may have also intervened through postdepositional ravaging. This first faunal assemblage potentially created by lions constitutes a new framework for neotaphonomic studies. Since lions may accumulate carcasses under exceptional circumstances, such as those documented at the site reported here, this finding may have important consequences for interpretations of early archaeological and paleontological sites, which provide key information about human evolution. PMID:27144649

  8. After Three Gorges Dam: What have we learned?

    Science.gov (United States)

    Natali, J.; Williams, P.; Wong, R.; Kondolf, G. M.

    2013-12-01

    China is at a critical point in its development path. By investing heavily in large-scale infrastructure, the rewards of economic growth weigh against long-term environmental and social costs. The construction of Three Gorges Dam, the world's largest hydroelectric project, began in 1994. Between 2002 and 2010, its 660 kilometer reservoir filled behind a 181 meter dam, displacing at least 1.4 million people and transforming Asia's longest river (the Yangtze) while generating nearly 100 billion kWh/yr of electricity -- 2.85% of China's current electric power usage. As the mega-project progenitor in a cascade of planned dams, the Three Gorges Dam emerges as a test case for how China will plan, execute and mitigate its development pathway and the transformation of its environment. Post-Project Assessments (PPA) provide a systematic, scientific method for improving the practice of environmental management - particularly as they apply to human intervention in river systems. In 2012, the Department of Landscape Architecture and Environmental Planning at University of California, Berkeley organized a symposium-based PPA for the Three Gorges Dam on the Yangtze River. Prior to this symposium, the twelve invited Chinese scientists, engineers and economists with recent research on Three Gorges Dam had not had the opportunity to present their evaluations together in an open, public forum. With a 50-year planning horizon, the symposium's five sessions centered on impacts on flows, geomorphology, geologic hazards, the environment and socioeconomic effects. Three Gorges' project goals focused on flood control, hydropower and improved navigation. According to expert research, major changes in sediment budget and flow regime from reservoir operation have significantly reduced sediment discharge into the downstream river and estuary, initiating a series of geomorphic changes with ecological and social impacts. While the dam reduces high flow stages from floods originating above the

  9. Communication activities for NUMO's site selection process

    International Nuclear Information System (INIS)

    Takeuchi, Mitsuo; Okuyama, Shigeru; Kitayama, Kazumi; Kuba, Michiyoshi

    2004-01-01

    A siting program for geological disposal of high-level radioactive waste (HLW) in Japan has just started and is moving into a new stage of communication with the public. A final repository site will be selected via a stepwise process, as stipulated in the Specified Radioactive Waste Final Disposal Act promulgated in June 2000. Based on the Act, the site selection process of the Nuclear Waste Management Organization of Japan (NUMO, established in October 2000) will be carried out in the three steps: selection of Preliminary Investigation Areas (PIAs), selection of Detailed Investigation Areas (DIAs) and selection of the Repository Site. The Act also defines NUMO's responsibilities in terms of implementing the HLW disposal program in an open and transparent manner. NUMO fully understands the importance of public participation in its activities and is aiming to promote public involvement in the process of site selection based on a fundamental policy, which consists of 'adopting a stepwise approach', 'respecting the initiative of municipalities' and 'ensuring transparency in information disclosure'. This policy is clearly reflected in the adoption of an open solicitation approach for volunteer municipalities for Preliminary Investigation Areas (PIAs). NUMO made the official announcement of the start of its open solicitation program on 19 December 2002. This paper outlines how NUMO's activities are currently carried out with a view to encouraging municipalities to volunteer as PIAs and how public awareness of the safety of the HLW disposal is evaluated at this stage

  10. Seismic activity parameters of the Finnish potential repository sites

    International Nuclear Information System (INIS)

    Saari, J.

    2000-10-01

    Posiva Oy has started a project for estimating the possible earthquake induced rock movements on the deposition holes containing canisters of spent nuclear fuel. These estimates will be made for the four investigation sites, Romuvaara, Kivetty, Olkiluoto and Haestholmen. This study deals with the current and future seismicity associated with the above mentioned sites. Seismic belts that participate the seismic behaviour of the studied sites have been identified and the magnitude-frequency distributions of these belts have been estimated. The seismic activity parameters of the sites have been deduced from the characteristics of the seismic belts in order to forecast the seismicity during the next 100,000 years. The report discusses the possible earthquakes induced by future glaciation. The seismic interpretation seems to indicate that the previous postglacial faults in Finnish Lapland have been generated in compressional environment. The orientation of the rather uniform compression has been NW-SE, which coincide with the current stress field. It seems that, although the impact of postglacial crustal rebound must have been significant, the impact of plate tectonics has been dominant. A major assumption of this study has been that future seismicity will generally resemble the current seismicity. However, when the postglacial seismicity is concerned, the magnitude-frequency distribution is likely different and the expected maximum magnitude will be higher. Maximum magnitudes of future postglacial earthquakes have been approximated by strain release examinations. Seismicity has been examined within the framework of the lineament maps, in order to associate the future significant earthquakes with active fault zones in the vicinity of the potential repository sites. (orig.)

  11. Active site mutations change the cleavage specificity of neprilysin.

    Directory of Open Access Journals (Sweden)

    Travis Sexton

    Full Text Available Neprilysin (NEP, a member of the M13 subgroup of the zinc-dependent endopeptidase family is a membrane bound peptidase capable of cleaving a variety of physiological peptides. We have generated a series of neprilysin variants containing mutations at either one of two active site residues, Phe(563 and Ser(546. Among the mutants studied in detail we observed changes in their activity towards leucine(5-enkephalin, insulin B chain, and amyloid β(1-40. For example, NEP(F563I displayed an increase in preference towards cleaving leucine(5-enkephalin relative to insulin B chain, while mutant NEP(S546E was less discriminating than neprilysin. Mutants NEP(F563L and NEP(S546E exhibit different cleavage site preferences than neprilysin with insulin B chain and amyloid ß(1-40 as substrates. These data indicate that it is possible to alter the cleavage site specificity of neprilysin opening the way for the development of substrate specific or substrate exclusive forms of the enzyme with enhanced therapeutic potential.

  12. Current activities handbook: formerly utilized sites remedial action program

    Energy Technology Data Exchange (ETDEWEB)

    None

    1981-02-27

    This volume is one of a series produced under contract with the DOE, by Politech Corporation to develop a legislative and regulatory data base to assist the FUSRAP management in addressing the institutional and socioeconomic issues involved in carrying out the Formerly Utilized Sites Remedial Action Program. This Information Handbook series contains information about all relevant government agencies at the Federal and state levels, the pertinent programs they administer, each affected state legislature, and current Federal and state legislative and regulatory initiatives. This volume is a compilation of information about the activities each of the thirteen state legislatures potentially affected by the Formerly Utilized Sites Remedial Action Program. It contains a description of the state legislative procedural rules and a schedule of each legislative session; a summary of pending relevant legislation; the name and telephone number of legislative and state agency contacts; and the full text of all bills identified.

  13. Current activities handbook: formerly utilized sites remedial action program

    International Nuclear Information System (INIS)

    1981-01-01

    This volume is one of a series produced under contract with the DOE, by Politech Corporation to develop a legislative and regulatory data base to assist the FUSRAP management in addressing the institutional and socioeconomic issues involved in carrying out the Formerly Utilized Sites Remedial Action Program. This Information Handbook series contains information about all relevant government agencies at the Federal and state levels, the pertinent programs they administer, each affected state legislature, and current Federal and state legislative and regulatory initiatives. This volume is a compilation of information about the activities each of the thirteen state legislatures potentially affected by the Formerly Utilized Sites Remedial Action Program. It contains a description of the state legislative procedural rules and a schedule of each legislative session; a summary of pending relevant legislation; the name and telephone number of legislative and state agency contacts; and the full text of all bills identified

  14. [Research progress on remote sensing of ecological and environmental changes in the Three Gorges Reservoir area, China].

    Science.gov (United States)

    Teng, Ming-jun; Zeng, Li-xiong; Xiao, Wen-fa; Zhou, Zhi-xiang; Huang, Zhi-lin; Wang, Peng-cheng; Dian, Yuan-yong

    2014-12-01

    The Three Gorges Reservoir area (TGR area) , one of the most sensitive ecological zones in China, has dramatically changes in ecosystem configurations and services driven by the Three Gorges Engineering Project and its related human activities. Thus, understanding the dynamics of ecosystem configurations, ecological processes and ecosystem services is an attractive and critical issue to promote regional ecological security of the TGR area. The remote sensing of environment is a promising approach to the target and is thus increasingly applied to and ecosystem dynamics of the TGR area on mid- and macro-scales. However, current researches often showed controversial results in ecological and environmental changes in the TGR area due to the differences in remote sensing data, scale, and land-use/cover classification. Due to the complexity of ecological configurations and human activities, challenges still exist in the remote-sensing based research of ecological and environmental changes in the TGR area. The purpose of this review was to summarize the research advances in remote sensing of ecological and environmental changes in the TGR area. The status, challenges and trends of ecological and environmental remote-sensing in the TGR area were further discussed and concluded in the aspect of land-use/land-cover, vegetation dynamics, soil and water security, ecosystem services, ecosystem health and its management. The further researches on the remote sensing of ecological and environmental changes were proposed to improve the ecosystem management of the TGR area.

  15. Investigation and analysis of hazardous waste in the Three Gorges Area of Chongqing region

    Institute of Scientific and Technical Information of China (English)

    LIU Li; LIU Xi-rong; WANG Li-ao; ZHOU Zai-jiang

    2004-01-01

    This article describes the investigation of hazardous waste (HW) in the Three Gorges Area of Chongqing region, which indicates that by May 2002, the dumped HW therein amounted to 14 600 t and was mainly distributed in five districts and counties with 11 000 t in Fuling, 1 650 t in Fengdu, 950 t in Wanzhou; 630 t in Wushan and 430 t in Yunyang. The total amount was composed of 9 670 t chromic residue, 2 310 t waste oil and residue, 410 t waste (false) fertilizer, 28 t waste chemical medicine, 26 t waste materials and 2 200 t other things including acid residue, waste asbestos, fluorine silicate,pigment, additive, waste acid, alkali, nitric acid, vitriol, lead mud, storage battery, calcium carbide, potassium cyanide, polluted soil, discard dynamite, waste packing barrel of cyanides, etc. In all of the HW, 578 t can be treated by chemical neutralization and stabilization technology such as redox, chemical precipitation, acid and alkali neutralization, etc., and the rest is temporarily untreatble and should be removed and piled at a temporary storage site above the 177 m water level of the dam with an aim to be transported to a future disposal site for innocuous treatment.

  16. Hydraulic design of Three Gorges right bank powerhouse turbine for improvement of hydraulic stability

    International Nuclear Information System (INIS)

    Shi, Q

    2010-01-01

    This paper presents the hydraulic design of Three Gorges Right Bank Powerhouse turbine for improvement of hydraulic stability. The technical challenges faced in the hydraulic design of the turbine are given. The method of hydraulic design for improving the hydraulic stability and particularly for eliminating the upper part load pressure pulsations is clarified. The final hydraulic design results of Three Gorges Right Bank Powerhouse turbine based on modern hydraulic design techniques are presented.

  17. Hydraulic design of Three Gorges right bank powerhouse turbine for improvement of hydraulic stability

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Q, E-mail: qhshi@dfem.com.c [Dong Fang Electrical Machinery Co., Ltd., DEC 188, Huanghe West Road, Deyang, 618000 (China)

    2010-08-15

    This paper presents the hydraulic design of Three Gorges Right Bank Powerhouse turbine for improvement of hydraulic stability. The technical challenges faced in the hydraulic design of the turbine are given. The method of hydraulic design for improving the hydraulic stability and particularly for eliminating the upper part load pressure pulsations is clarified. The final hydraulic design results of Three Gorges Right Bank Powerhouse turbine based on modern hydraulic design techniques are presented.

  18. Stereospecific suppression of active site mutants by methylphosphonate substituted substrates reveals the stereochemical course of site-specific DNA recombination

    OpenAIRE

    Rowley, Paul A.; Kachroo, Aashiq H.; Ma, Chien-Hui; Maciaszek, Anna D.; Guga, Piotr; Jayaram, Makkuni

    2015-01-01

    Tyrosine site-specific recombinases, which promote one class of biologically important phosphoryl transfer reactions in DNA, exemplify active site mechanisms for stabilizing the phosphate transition state. A highly conserved arginine duo (Arg-I; Arg-II) of the recombinase active site plays a crucial role in this function. Cre and Flp recombinase mutants lacking either arginine can be rescued by compensatory charge neutralization of the scissile phosphate via methylphosphonate (MeP) modificati...

  19. Probing the active sites for CO dissociation on ruthenium nanoparticles

    DEFF Research Database (Denmark)

    Strebel, Christian Ejersbo; Murphy, Shane; Nielsen, Rasmus Munksgård

    2012-01-01

    affect the CO dissociation activity. The Ru nanoparticles were synthesized in a UHV chamber by gas-aggregation magnetron sputtering in the size range from 3 to 15 nm and the morphology was investigated in situ by scanning tunneling microscopy and ex situ by high resolution transmission electron...... microscopy. Surprisingly, it was found that larger particles were more active per surface area for CO dissociation. It is suggested that this is due to larger particles exposing a more rough surface than the smaller particles, giving rise to a higher relative amount of under-coordinated adsorption sites...... on the larger particles. The induced surface roughness is proposed to be a consequence of the growth processes in the gas-aggregation chamber....

  20. Study the active site of flavonoid applying radiation chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jilan; Sun Gang; Zhang Fugen; He Yongke; Li Jiuqiang [Department of Technical Physics, Peking Univ., Beijing (China)

    2000-03-01

    Flavonoid are a large and important class of naturally occurring, low molecular weight benzo-{gamma}-pyrone derivatives which are reported to have a myriad of biological activities, but the study on the active sites of flavonoids is still ambiguous. In this paper, rutin, quercetin and baicalin have been selected as model compounds. It is well known that rutin is used in inhibiting arteriosclerosis and baicalin is antibacterial and antiviral. They have similar basic structure, but their medicinal properties are so different, why? As most flavonoids contain carbonyl group, which can capture electron effectively, we predict that flavonoids can capture electron to form radical anion. The formation of anion radical may have influence on the mitochondrial electron transport chain. The difference in the ability of forming anion radical may cause the difference in their medicinal effects. (author)

  1. Study the active site of flavonoid applying radiation chemistry

    International Nuclear Information System (INIS)

    Wu Jilan; Sun Gang; Zhang Fugen; He Yongke; Li Jiuqiang

    2000-01-01

    Flavonoid are a large and important class of naturally occurring, low molecular weight benzo-γ-pyrone derivatives which are reported to have a myriad of biological activities, but the study on the active sites of flavonoids is still ambiguous. In this paper, rutin, quercetin and baicalin have been selected as model compounds. It is well known that rutin is used in inhibiting arteriosclerosis and baicalin is antibacterial and antiviral. They have similar basic structure, but their medicinal properties are so different, why? As most flavonoids contain carbonyl group, which can capture electron effectively, we predict that flavonoids can capture electron to form radical anion. The formation of anion radical may have influence on the mitochondrial electron transport chain. The difference in the ability of forming anion radical may cause the difference in their medicinal effects. (author)

  2. Gravity Anomalies and Isostasy Deduced From New Dense Gravimetry Around the Tsangpo Gorge, Tibet

    Science.gov (United States)

    Fu, Guangyu; She, Yawen

    2017-10-01

    We built the first dense gravity network including 107 stations around the Tsangpo Gorge, Tibet, one of the hardest places in the world to reach, and conducted a gravity and hybrid GPS observation campaign in 2016. We computed the Bouguer gravity anomalies (BGAs) and free-air gravity anomalies (FGAs) and increased the resolution of the FGAs by merging the in situ data with EIGEN-6C4 gravity model data. The BGAs around the Tsangpo Gorge are in general negative and gradually decrease from south (-360 mGal) to north (-480 mGal). They indicate a uniformly dipping Moho around the Tsangpo Gorge that sinks from south to north at an angle of 12°. We introduced a method to compute the vertical tectonic stress of the lithosphere, a quantitative expression of isostasy, using BGA and terrain data, and applied it to the area around the Tsangpo Gorge. We found that the lithosphere of the upstream of the Tsangpo Gorge is roughly in an isostatic state, but the lithosphere of the downstream exhibits vertical tectonic stress of 50 MPa, which indicates the loss of a large amount of surface material. This result does not support the deduction of the valley bottom before uplift of the Tsangpo Gorge by Wang et al. (2014).

  3. Impacts of the Three Gorges Project on Local Climate

    Science.gov (United States)

    Song, Z.; Liang, S.; Feng, L.

    2015-12-01

    Three Gorges Project (TGP) is the largest hydroelectric project in the world and has led to significant land cover changes in Three Gorges Reservoir Area (TGRA). Since its construction the debates on its environmental and climatic impacts have never stopped, especially after the extreme drought and flood in Yangtze River Basin these years. TGP reached its final impounding water level in 2010. However, studies on systematically monitoring the long-term variations in surface and atmospheric parameters in TGRA are still lacking. In this study, three important surface parameters - surface albedo, land surface temperature (LST) and evapotranspiration (ET) and two climatic parameters - air temperature and precipitation were investigated from 2000 to 2013 by combining multiple remote sensing data and ground measurements. Results showed that along the reservoir albedo decreased significantly as a result of water impounding. Correspondingly, in the same region daytime LST decreased in spring and summer and nighttime LST increased in autumn and winter. In the western region of TGRA, albedo increased due to resettlement and LST also changed. The average ET increased by 20% in TGR but kept stable in the whole TGRA. In contrast to LST, air temperature showed less apparent spatial and temporal variability. Only in the region near the dam air temperature experienced a decrease at daytime and an increase at nighttime. Further analysis demonstrated precipitation revealed no apparent changes in TGRA and the precipitation anomaly in northwest of TGRA may not be connected with TGP. All of the findings provide a more substantial clues of local climate change caused by TGP.

  4. Tephrochronology of Bed II, Olduvai Gorge, Tanzania, and placement of the Oldowan-Acheulean transition.

    Science.gov (United States)

    McHenry, Lindsay J; Stanistreet, Ian G

    2018-04-12

    Tuffaceous marker beds, derived from volcanic products from the Ngorongoro Volcanic Highlands, help define a stratigraphic framework for the world-renowned fossil and stone tool record exposed at Olduvai Gorge, Tanzania. However, previous efforts to constrain this tuff record, especially for Olduvai Bed II, have been limited because of erosion, contamination, reworking, and the alteration of volcanic glass under saline-alkaline conditions. This paper applies previously defined geochemical and mineralogical "fingerprints" for several major Bed II marker tuffs, based on glass (where available) and phenocrysts more resistant to alteration (feldspar, hornblende, augite, and titanomagnetite), to tuffs from stratigraphic sections in the Olduvai Junction Area, including previously and recently excavated Acheulean and Oldowan sites (HWK EE (Locality (Loc) 42), EF-HR (Loc 12a), FLK (Loc 45), and MNK (Loc 88)). The Middle Bed II Bird Print Tuff (BPT) is found to be more compositionally variable than previously reported but is still valuable as a stratigraphic marker over short distances. The confirmation of blocks of Tuff IID in conglomerate helps constrain Upper Bed II stratigraphy at sites where in-situ tuffs are absent. This paper also compiles the results of published geochronological research, providing stratigraphic context and updating previously reported dates using a consistent 40 Ar/ 39 Ar reference standard age. The results of this work support the following paleoanthropologically relevant conclusions: 1) the early Acheulean site EF-HR (Loc 12a) is situated above the level of Hay's Tuff IIC, and thus sits in Upper rather than Middle Bed II, (2) the HWK EE (Loc 42) Oldowan site is constrained between Tuff IIA and Tuff IIB, just above the boundary between Lower and Middle Bed II, and 3) the Acheulean site at FLK W most likely lies within the Middle Augitic Sandstone, above Tuff IIB, similar to the placements by Leakey and Hay for the earliest Acheulean at Olduvai

  5. Maxey Flats low-level waste disposal site closure activities

    International Nuclear Information System (INIS)

    Haight, C.P.; Mills, D.; Razor, J.E.

    1987-01-01

    The Maxey Flats Radioactive Waste Disposal Facility in Fleming County, Kentucky is in the process of being closed. The facility opened for commercial business in the spring of 1963 and received approximately 4.75 million cubic feet of radioactive waste by the time it was closed in December of 1977. During fourteen years of operation approximately 2.5 million curies of by-product material, 240,000 kilograms of source material, and 430 kilograms of special nuclear material were disposed. The Commonwealth purchased the lease hold estate and rights in May 1978 from the operating company. This action was taken to stabilize the facility and prepare it for closure consisting of passive care and monitoring. To prepare the site for closure, a number of remedial activities had to be performed. The remediation activities implemented have included erosion control, surface drainage modifications, installation of a temporary plastic surface cover, leachate removal, analysis, treatment and evaporation, US DOE funded evaporator concentrates solidification project and their on-site disposal in an improved disposal trench with enhanced cover for use in a humid environment situated in a fractured geology, performance evaluation of a grout injection demonstration, USGS subsurface geologic investigation, development of conceptual closure designs, and finally being added to the US EPA National Priority List for remediation and closure under Superfund. 13 references, 3 figures

  6. Eel calcitonin binding site distribution and antinociceptive activity in rats

    International Nuclear Information System (INIS)

    Guidobono, F.; Netti, C.; Sibilia, V.; Villa, I.; Zamboni, A.; Pecile, A.

    1986-01-01

    The distribution of binding site for [ 125 I]-eel-calcitonin (ECT) to rat central nervous system, studied by an autoradiographic technique, showed concentrations of binding in the diencephalon, the brain stem and the spinal cord. Large accumulations of grains were seen in the hypothalamus, the amygdala, in the fasciculus medialis prosencephali, in the fasciculus longitudinalis medialis, in the ventrolateral part of the periventricular gray matter, in the lemniscus medialis and in the raphe nuclei. The density of grains in the reticular formation and in the nucleus tractus spinalis nervi trigemini was more moderate. In the spinal cord, grains were scattered throughout the dorsal horns. Binding of the ligand was displaced equally by cold ECT and by salmon CT(sCT), indicating that both peptides bind to the same receptors. Human CT was much weaker than sCT in displacing [ 125 I]-ECT binding. The administration of ECT into the brain ventricles of rats dose-dependently induced a significant and long-lasting enhancement of hot-plate latencies comparable with that obtained with sCT. The antinociceptive activity induced by ECT is compatible with the topographical distribution of binding sites for the peptide and is a further indication that fish CTs are active in the mammalian brain

  7. Metal active site elasticity linked to activation of homocysteine in methionine synthases

    Energy Technology Data Exchange (ETDEWEB)

    Koutmos, Markos; Pejchal, Robert; Bomer, Theresa M.; Matthews, Rowena G.; Smith, Janet L.; Ludwig, Martha L. (Michigan)

    2008-04-02

    Enzymes possessing catalytic zinc centers perform a variety of fundamental processes in nature, including methyl transfer to thiols. Cobalamin-independent (MetE) and cobalamin-dependent (MetH) methionine synthases are two such enzyme families. Although they perform the same net reaction, transfer of a methyl group from methyltetrahydrofolate to homocysteine (Hcy) to form methionine, they display markedly different catalytic strategies, modular organization, and active site zinc centers. Here we report crystal structures of zinc-replete MetE and MetH, both in the presence and absence of Hcy. Structural investigation of the catalytic zinc sites of these two methyltransferases reveals an unexpected inversion of zinc geometry upon binding of Hcy and displacement of an endogenous ligand in both enzymes. In both cases a significant movement of the zinc relative to the protein scaffold accompanies inversion. These structures provide new information on the activation of thiols by zinc-containing enzymes and have led us to propose a paradigm for the mechanism of action of the catalytic zinc sites in these and related methyltransferases. Specifically, zinc is mobile in the active sites of MetE and MetH, and its dynamic nature helps facilitate the active site conformational changes necessary for thiol activation and methyl transfer.

  8. Differential active site loop conformations mediate promiscuous activities in the lactonase SsoPox.

    Directory of Open Access Journals (Sweden)

    Julien Hiblot

    Full Text Available Enzymes are proficient catalysts that enable fast rates of Michaelis-complex formation, the chemical step and products release. These different steps may require different conformational states of the active site that have distinct binding properties. Moreover, the conformational flexibility of the active site mediates alternative, promiscuous functions. Here we focused on the lactonase SsoPox from Sulfolobus solfataricus. SsoPox is a native lactonase endowed with promiscuous phosphotriesterase activity. We identified a position in the active site loop (W263 that governs its flexibility, and thereby affects the substrate specificity of the enzyme. We isolated two different sets of substitutions at position 263 that induce two distinct conformational sampling of the active loop and characterized the structural and kinetic effects of these substitutions. These sets of mutations selectively and distinctly mediate the improvement of the promiscuous phosphotriesterase and oxo-lactonase activities of SsoPox by increasing active-site loop flexibility. These observations corroborate the idea that conformational diversity governs enzymatic promiscuity and is a key feature of protein evolvability.

  9. Flood characteristics for the New River in the New River Gorge National River, West Virginia

    Science.gov (United States)

    Wiley, J.B.; Cunningham, M.K.

    1994-01-01

    The frequency and magnitude of flooding of the New River in the New River Gorge National River was studied. A steady-state, one-dimensional flow model was applied to the study reach. Rating curves, cross sections, and Manning's roughness coefficients that were used are presented in this report. Manning's roughness coefficients were evaluated by comparing computed elevations (from application of the steady-state, one-dimensional flow model) to rated elevations at U.S. Geological Survey (USGS) streamflow-gaging stations and miscellaneous-rating sites. Manning's roughness coefficients ranged from 0.030 to 0.075 and varied with hydraulic depth. The 2-, 25-, and 100-year flood discharges were esti- mated on the basis of information from flood- insurance studies of Summers County, Fayette County, and the city of Hinton, and flood-frequency analysis of discharge records for the USGS streamflow-gaging stations at Hinton and Thurmond. The 100-year discharge ranged from 107,000 cubic feet per second at Hinton to 150,000 cubic feet per second at Fayette.

  10. Landslide Monitoring Network Establishment within Unified Datum and Stability Analysis in the Three Gorges Reservoir Area

    Directory of Open Access Journals (Sweden)

    Shengxiang Huang

    2017-01-01

    Full Text Available A landslide monitoring network construction within unified datum which combined fiducial points, working reference points, and monitoring points was intensively studied in the Three Gorges Reservoir area. With special long and narrow geographical location in the area, designing and building monitoring network was vital to the realization of landslide monitoring. To build such a network with high precision, this paper mainly focused on the following four aspects: (1 method of using multiple GPS reference stations to build a unified datum network and subnet adjustment, (2 GPS data processing algorithm with millimeter level, (3 analysis of influence on the adjustment resulting from systematic error of time evolution datum from different GPS observations, and (4 establishment and stability analysis of unified datum. Then, using global test and trial-and-error method to analyze the datum based on the GPS observations (2008~2011 of landslide monitoring network in the area, we concluded that there were moved reference points during the three years of high water impoundment, and the horizontal displacement of moved reference points was more than 4 cm, even up to 79.4 cm. The displacement direction of unstable reference points was inspected with geographical environment at sites, which revealed congruency between them.

  11. Active site loop conformation regulates promiscuous activity in a lactonase from Geobacillus kaustophilus HTA426.

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    Full Text Available Enzyme promiscuity is a prerequisite for fast divergent evolution of biocatalysts. A phosphotriesterase-like lactonase (PLL from Geobacillus kaustophilus HTA426 (GkaP exhibits main lactonase and promiscuous phosphotriesterase activities. To understand its catalytic and evolutionary mechanisms, we investigated a "hot spot" in the active site by saturation mutagenesis as well as X-ray crystallographic analyses. We found that position 99 in the active site was involved in substrate discrimination. One mutant, Y99L, exhibited 11-fold improvement over wild-type in reactivity (kcat/Km toward the phosphotriesterase substrate ethyl-paraoxon, but showed 15-fold decrease toward the lactonase substrate δ-decanolactone, resulting in a 157-fold inversion of the substrate specificity. Structural analysis of Y99L revealed that the mutation causes a ∼6.6 Å outward shift of adjacent loop 7, which may cause increased flexibility of the active site and facilitate accommodation and/or catalysis of organophosphate substrate. This study provides for the PLL family an example of how the evolutionary route from promiscuity to specificity can derive from very few mutations, which promotes alteration in the conformational adjustment of the active site loops, in turn draws the capacity of substrate binding and activity.

  12. Active site architecture of a sugar N-oxygenase.

    Science.gov (United States)

    Thoden, James B; Branch, Megan C; Zimmer, Alex L; Bruender, Nathan A; Holden, Hazel M

    2013-05-14

    KijD3 is a flavin-dependent N-oxygenase implicated in the formation of the nitro-containing sugar d-kijanose, found attached to the antibiotic kijanimicin. For this investigation, the structure of KijD3 in complex with FMN and its dTDP-sugar substrate was solved to 2.1 Å resolution. In contrast to the apoenzyme structure, the C-terminus of the protein becomes ordered and projects into the active site cleft [Bruender, N. A., Thoden, J. B., and Holden, H. M. (2010) Biochemistry 49, 3517-3524]. The amino group of the dTDP-aminosugar that is oxidized is located 4.9 Å from C4a of the flavin ring. The model provides a molecular basis for understanding the manner in which KijD3 catalyzes its unusual chemical transformation.

  13. Crystal structure of snake venom acetylcholinesterase in complex with inhibitory antibody fragment Fab410 bound at the peripheral site: evidence for open and closed states of a back door channel.

    Science.gov (United States)

    Bourne, Yves; Renault, Ludovic; Marchot, Pascale

    2015-01-16

    The acetylcholinesterase found in the venom of Bungarus fasciatus (BfAChE) is produced as a soluble, non-amphiphilic monomer with a canonical catalytic domain but a distinct C terminus compared with the other vertebrate enzymes. Moreover, the peripheral anionic site of BfAChE, a surface site located at the active site gorge entrance, bears two substitutions altering sensitivity to cationic inhibitors. Antibody Elec410, generated against Electrophorus electricus acetylcholinesterase (EeAChE), inhibits EeAChE and BfAChE by binding to their peripheral sites. However, both complexes retain significant residual catalytic activity, suggesting incomplete gorge occlusion by bound antibody and/or high frequency back door opening. To explore a novel acetylcholinesterase species, ascertain the molecular bases of inhibition by Elec410, and document the determinants and mechanisms for back door opening, we solved a 2.7-Å resolution crystal structure of natural BfAChE in complex with antibody fragment Fab410. Crystalline BfAChE forms the canonical dimer found in all acetylcholinesterase structures. Equally represented open and closed states of a back door channel, associated with alternate positions of a tyrosine phenol ring at the active site base, coexist in each subunit. At the BfAChE molecular surface, Fab410 is seated on the long Ω-loop between two N-glycan chains and partially occludes the gorge entrance, a position that fully reflects the available mutagenesis and biochemical data. Experimentally based flexible molecular docking supports a similar Fab410 binding mode onto the EeAChE antigen. These data document the molecular and dynamic peculiarities of BfAChE with high frequency back door opening, and the mode of action of Elec410 as one of the largest peptidic inhibitors targeting the acetylcholinesterase peripheral site. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Monitoring Vertical Crustal Deformation and Gravity Variations during Water Level Changes at the Three Gorges Reservoir

    Directory of Open Access Journals (Sweden)

    WANG Wei

    2017-06-01

    Full Text Available Monitoring vertical crustal deformation and gravity changes during water level changes at the Three Gorges reservoir is important for the safe operation of the Three Gorges Dam and for the monitoring and prevention of a regional geological disaster. In this study, we determined vertical crustal deformation and gravity changes during water level variations of the Three Gorges reservoir from direct calculations and actual measurements and a comprehensive solution. We used water areas extracted image data from the ZY-3 satellite and water level data to calculate gravity changes and vertical crustal deformation caused by every 5 m change in the water level due to storage and drainage of the Three Gorges reservoir from 145 m to 175 m. The vertical crustal deformation was up to 30 mm. The location of gravity change above 20 μ Gal(1 Gal=10-2 m/s2 was less than 2 km from the centerline of the Yangtze River. The CORS ES13 in Badong, near the reservoir, measured the vertical crustal deformation during water level changes. Because of the small number of CORS and gravity stations in the Three Gorges reservoir area, monitoring deformation and gravity related to changes in the Three Gorges reservoir water level cannot be closely followed. Using 26 CORS and some of the gravity stations in the Three Gorges area and based on loading deformation and the spherical harmonic analysis method, an integrated solution of vertical deformation and gravity variations during water level changes of the reservoir was determined, which is consistent with the actual CORS monitoring results. By comparison, we found that an integrated solution based on a CORS network can effectively enhance the capability of monitoring vertical crustal deformation and gravity changes during water level variations of the reservoir.

  15. Zymogen Activation and Subcellular Activity of Subtilisin Kexin Isozyme 1/Site 1 Protease*

    Science.gov (United States)

    da Palma, Joel Ramos; Burri, Dominique Julien; Oppliger, Joël; Salamina, Marco; Cendron, Laura; de Laureto, Patrizia Polverino; Seidah, Nabil Georges; Kunz, Stefan; Pasquato, Antonella

    2014-01-01

    The proprotein convertase subtilisin kexin isozyme 1 (SKI-1)/site 1 protease (S1P) plays crucial roles in cellular homeostatic functions and is hijacked by pathogenic viruses for the processing of their envelope glycoproteins. Zymogen activation of SKI-1/S1P involves sequential autocatalytic processing of its N-terminal prodomain at sites B′/B followed by the herein newly identified C′/C sites. We found that SKI-1/S1P autoprocessing results in intermediates whose catalytic domain remains associated with prodomain fragments of different lengths. In contrast to other zymogen proprotein convertases, all incompletely matured intermediates of SKI-1/S1P showed full catalytic activity toward cellular substrates, whereas optimal cleavage of viral glycoproteins depended on B′/B processing. Incompletely matured forms of SKI-1/S1P further process cellular and viral substrates in distinct subcellular compartments. Using a cell-based sensor for SKI-1/S1P activity, we found that 9 amino acid residues at the cleavage site (P1–P8) and P1′ are necessary and sufficient to define the subcellular location of processing and to determine to what extent processing of a substrate depends on SKI-1/S1P maturation. In sum, our study reveals novel and unexpected features of SKI-1/S1P zymogen activation and subcellular specificity of activity toward cellular and pathogen-derived substrates. PMID:25378398

  16. Gravity inversion of deep-crust and mantle interfaces in the Three Gorges area

    Directory of Open Access Journals (Sweden)

    Wang Jian

    2012-11-01

    Full Text Available To better understand the heterogeneity of deep-crust and mantle interfaces in the region of the Three Gorges, China, we used the Parker-Oldenburg iterative inversion method to invert existing Bouguer gravity data from the Three Gorges area (1 : 500000, a new gravity map of the Three Gorges Dam (1 : 200000, and the results of deep seismic soundings. The inversion results show a Moho depth of 42 km between Badong and Zigui and the depth of the B2 lower-crustal interface beneath the Jianghan Plain and surrounding areas at 21–25 km. The morphology of crustal interfaces and the surface geology present an overpass structure. The mid-crust beneath the Three Gorges Dam is approximately 9 km thick, which is the thinnest in the Three Gorges area and may be related to the shallow low-density body near the Huangling anticline. The upper crust is seismogenic, and there is a close relationship between seismicity and the deep-crust and mantle interfaces. For example, the M5. 1 Zigui earthquake occurred where the gradients of the Moho and the B2 interface are the steepest, showing that deep structure has a very important effect on regional seismicity.

  17. Characterization of Active Site Residues of Nitroalkane Oxidase†

    Science.gov (United States)

    Valley, Michael P.; Fenny, Nana S.; Ali, Shah R.; Fitzpatrick, Paul F.

    2010-01-01

    The flavoenzyme nitroalkane oxidase catalyzes the oxidation of primary and secondary nitrolkanes to the corresponding aldehydes and ketones plus nitrite. The structure of the enzyme shows that Serl71 forms a hydrogen bond to the flavin N5, suggesting that it plays a role in catalysis. Cys397 and Tyr398 were previously identified by chemical modification as potential active site residues. To more directly probe the roles of these residues, the S171A, S171V, S171T, C397S, and Y398F enzymes have been characterized with nitroethane as substrate. The C397S and Y398 enzymes were less stable than the wild-type enzyme, and the C397S enzyme routinely contained a substoichiometric amount of FAD. Analysis of the steady-state kinetic parameters for the mutant enzymes, including deuterium isotope effects, establishes that all of the mutations result in decreases in the rate constants for removal of the substrate proton by ~5-fold and decreases in the rate constant for product release of ~2-fold. Only the S171V and S171T mutations alter the rate constant for flavin oxidation. These results establish that these residues are not involved in catalysis, but rather are required for maintaining the protein structure. PMID:20056514

  18. Characterization of active site residues of nitroalkane oxidase.

    Science.gov (United States)

    Valley, Michael P; Fenny, Nana S; Ali, Shah R; Fitzpatrick, Paul F

    2010-06-01

    The flavoenzyme nitroalkane oxidase catalyzes the oxidation of primary and secondary nitroalkanes to the corresponding aldehydes and ketones plus nitrite. The structure of the enzyme shows that Ser171 forms a hydrogen bond to the flavin N5, suggesting that it plays a role in catalysis. Cys397 and Tyr398 were previously identified by chemical modification as potential active site residues. To more directly probe the roles of these residues, the S171A, S171V, S171T, C397S, and Y398F enzymes have been characterized with nitroethane as substrate. The C397S and Y398 enzymes were less stable than the wild-type enzyme, and the C397S enzyme routinely contained a substoichiometric amount of FAD. Analysis of the steady-state kinetic parameters for the mutant enzymes, including deuterium isotope effects, establishes that all of the mutations result in decreases in the rate constants for removal of the substrate proton by approximately 5-fold and decreases in the rate constant for product release of approximately 2-fold. Only the S171V and S171T mutations alter the rate constant for flavin oxidation. These results establish that these residues are not involved in catalysis, but rather are required for maintaining the protein structure. 2009 Elsevier Inc. All rights reserved.

  19. Disturbance opens recruitment sites for bacterial colonization in activated sludge.

    Science.gov (United States)

    Vuono, David C; Munakata-Marr, Junko; Spear, John R; Drewes, Jörg E

    2016-01-01

    Little is known about the role of immigration in shaping bacterial communities or the factors that may dictate success or failure of colonization by bacteria from regional species pools. To address these knowledge gaps, the influence of bacterial colonization into an ecosystem (activated sludge bioreactor) was measured through a disturbance gradient (successive decreases in the parameter solids retention time) relative to stable operational conditions. Through a DNA sequencing approach, we show that the most abundant bacteria within the immigrant community have a greater probability of colonizing the receiving ecosystem, but mostly as low abundance community members. Only during the disturbance do some of these bacterial populations significantly increase in abundance beyond background levels and in few cases become dominant community members post-disturbance. Two mechanisms facilitate the enhanced enrichment of immigrant populations during disturbance: (i) the availability of resources left unconsumed by established species and (ii) the increased availability of niche space for colonizers to establish and displace resident populations. Thus, as a disturbance decreases local diversity, recruitment sites become available to promote colonization. This work advances our understanding of microbial resource management and diversity maintenance in complex ecosystems. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. Active site labeling of the guanine-7-methyltransferase

    International Nuclear Information System (INIS)

    Streaker, E.; Sitz, T.O.

    1992-01-01

    Studies on the guanine-7-methyltransferase have defined three domains in the active site: the S-adenosylmethionine (SAM) region, the cap region (GpppG), and the RNA binding domain (--NpNpNpNpNp---). The authors attempted to label the SAM binding domain by a photoaffinity label using 8-azido-SAM and another method using 3 H-SAM and long exposures to uv-light. Neither method was successful. The next approach was to attempt to label the cap-RNA binding domain (GpppGpNpNpNpNpN) by synthesizing RNA containing 8-azido-Ap using an in vitro transcription system and T7 RNA polymerase. The 8-azido-ATP inhibited the T7 RNA polymerase preventing the synthesis of RNA. As they were unable to synthesize the photoaffinity label, they next tried to synthesize an end labeled RNA and directly label by long exposures to uv-light. When the enzyme was incubated with 32 P-labeled RNA for 15 min at 37 degrees and then exposed to a germicidal lamp for various times at O degrees, optimal labeling occurred after 45 min. Various enzyme preparations were labeled by this method and two polypeptides were found to specifically bind the non-methylated mRNA analog. This labeling method should allow characterization of the subunit structure and generate information about the nature of the RNA binding domain

  1. Downstream Yangtze River levels impacted by Three Gorges Dam

    International Nuclear Information System (INIS)

    Wang, Jida; Sheng, Yongwei; Gleason, Colin J; Wada, Yoshihide

    2013-01-01

    Changes in the Yangtze River level induced by large-scale human water regulation have profound implications on the inundation dynamics of surrounding lakes/wetlands and the integrity of related ecosystems. Using in situ measurements and hydrological simulation, this study reveals an altered Yangtze level regime downstream from the Three Gorges Dam (TGD) to the Yangtze estuary in the East China Sea as a combined result of (i) TGD’s flow regulation and (ii) Yangtze channel erosion due to reduced sediment load. During the average annual cycle of TGD’s regular flow control in 2009–2012, downstream Yangtze level variations were estimated to have been reduced by 3.9–13.5% at 15 studied gauging stations, manifested as evident level decrease in fall and increase in winter and spring. The impacts on Yangtze levels generally diminished in a longitudinal direction from the TGD to the estuary, with a total time lag of ∼9–12 days. Chronic Yangtze channel erosion since the TGD closure has lowered water levels in relation to flows at most downstream stations, which in turn counteracts the anticipated level increase by nearly or over 50% in winter and spring while reinforcing the anticipated level decrease by over 20% in fall. Continuous downstream channel erosion in the near future may further counteract the benefit of increased Yangtze levels during TGD’s water supplement in winter and accelerate the receding of inundation areas/levels of downstream lakes in fall. (letter)

  2. Modeling the ecological impacts of Flaming Gorge Dam operations

    International Nuclear Information System (INIS)

    Yin, S.C.L.; LaGory, K.E.; Hayse, J.W.; Hlohowskyj, I.; Van Lonkhuyzen, R.A.; Cho, H.E.

    1996-01-01

    Hydropower operations at Flaming Gorge Dam on the Green River in Utah, US, can produce rapid downstream changes in flow and stage during a day. These changes can, in turn, affect ecological resources below the dam, including riparian vegetation, trout, and endangered fish. Four hydropower operational scenarios featuring varying degrees of hydropower-induced flow fluctuation were evaluated with hydrologic models and multispectral aerial videography of the river. Year-round high fluctuations would support the least amount of stable spawning habitat for trout and nursery habitat for endangered fish, and would have the greatest potential for reducing growth and over winter survival of fish. Seasonally, adjusted moderate fluctuation and seasonally adjusted steady flow scenarios could increase food production and over winter survival and would provide the greatest amount of spawning and nursery habitat for fish. The year-round high fluctuation, seasonally adjusted high fluctuation, and seasonally adjusted moderate fluctuation scenarios would result in a 5% decrease in upper riparian zone habitat. the seasonally adjusted steady flow scenario would result in an 8% increase in upper riparian zone habitat. Lower riparian zone habitat would increase by about 17% for year-round and seasonally adjusted high fluctuating flow scenarios but decrease by about 24% and 69% for seasonally adjusted moderate fluctuating and steady flow scenarios, respectively

  3. Finnsjoen study site. Scope of activities and main results

    International Nuclear Information System (INIS)

    Ahlbom, K.; Andersson, J.E.; Andersson, Peter; Ittner, T.; Tiren, S.; Ljunggren, C.

    1992-12-01

    The Finnsjoen study site was selected in 1977 to provide input to the KBS-1 and KBS-2 performance assessments. The site was later used as a test site for testing new instruments and new site characterization methods, as well as a research site for studying mainly groundwater flow and groundwater transport. All together, the Finnsjoen studies have involved 11 cored boreholes, down to max 700 m depth, and extensive borehole geophysical, geochemical and geohydraulic measurements, as well as rock stress measurements and tracer tests. This report presents the scope of the Finnsjoen studies together with main results. Conceptual uncertainties in assumptions and models are discussed with emphasis on the models used for the performance assessment SKB91. Of special interest for the Finnsjoen study site is the strong influence caused by a subhorizontal fracture zone on groundwater flow, transport and chemistry

  4. [Distribution of Mercury in Plants at Water-Level-Fluctuating Zone in the Three Gorges Reservoir].

    Science.gov (United States)

    Liang, Li; Wang, Yong-min; Li, Xian-yuan; Tang, Zhen-ya; Zhang, Xiang; Zhang, Cheng; WANG, Ding-yong

    2015-11-01

    The mercury (Hg) distribution and storage in plants at water-level-fluctuating zone (WLFZ) in the Three Gorges Reservoir were investigated by analyzing the total mercury(THg) and methylmercury ( MeHg) levels in different parts of plants collected from three typical sites including Shibaozhai, Zhenxi and Hanfeng Lake in WLFZ. The results indicated that THg and MeHg concentrations in plants ranged from (1.62 ± 0.57) to (49.42 ± 3.93) μg x kg(-1) and from (15.27 ± 7.09) to (1 974.67 ± 946.10) ng x kg(-1), respectively. In addition, THg levels in different plant parts followed the trend: root > leaf > stem, and similar trend for MeHg was observed with the highest level in root. An obvious spatial distribution was also found with the THg and MeHg levels in plants in Hanfeng higher than those in the same plants in the other two sampling sites (Shibaozhai and Zhenxi), and there was a difference of THg and MeHg storage in plants in various attitudes. The corresponding THg and MeHg storages were 145.3, 166.4, 124.3 and 88.2 mg x hm(-2), and 1.9, 2.7, 3.6 and 3.2 mg x hm(-2) in 145-150, 150-160, 160-170 and 170-175 m attitudes. The accumulation ability of dominant plants in WLFZ for THg (bioaccumulation factor, BAF 1).

  5. Assessment of online public opinions on large infrastructure projects: A case study of the Three Gorges Project in China

    International Nuclear Information System (INIS)

    Jiang, Hanchen; Qiang, Maoshan; Lin, Peng

    2016-01-01

    Public opinion becomes increasingly salient in the ex post evaluation stage of large infrastructure projects which have significant impacts to the environment and the society. However, traditional survey methods are inefficient in collection and assessment of the public opinion due to its large quantity and diversity. Recently, Social media platforms provide a rich data source for monitoring and assessing the public opinion on controversial infrastructure projects. This paper proposes an assessment framework to transform unstructured online public opinions on large infrastructure projects into sentimental and topical indicators for enhancing practices of ex post evaluation and public participation. The framework uses web crawlers to collect online comments related to a large infrastructure project and employs two natural language processing technologies, including sentiment analysis and topic modeling, with spatio-temporal analysis, to transform these comments into indicators for assessing online public opinion on the project. Based on the framework, we investigate the online public opinion of the Three Gorges Project on China's largest microblogging site, namely, Weibo. Assessment results present spatial-temporal distributions of post intensity and sentiment polarity, reveals major topics with different sentiments and summarizes managerial implications, for ex post evaluation of the world's largest hydropower project. The proposed assessment framework is expected to be widely applied as a methodological strategy to assess public opinion in the ex post evaluation stage of large infrastructure projects. - Highlights: • We developed a framework to assess online public opinion on large infrastructure projects with environmental impacts. • Indicators were built to assess post intensity, sentiment polarity and major topics of the public opinion. • We took the Three Gorges Project (TGP) as an example to demonstrate the effectiveness proposed framework.

  6. Assessment of online public opinions on large infrastructure projects: A case study of the Three Gorges Project in China

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Hanchen, E-mail: jhc13@mails.tsinghua.edu.cn; Qiang, Maoshan, E-mail: qiangms@tsinghua.edu.cn; Lin, Peng, E-mail: celinpe@mail.tsinghua.edu.cn

    2016-11-15

    Public opinion becomes increasingly salient in the ex post evaluation stage of large infrastructure projects which have significant impacts to the environment and the society. However, traditional survey methods are inefficient in collection and assessment of the public opinion due to its large quantity and diversity. Recently, Social media platforms provide a rich data source for monitoring and assessing the public opinion on controversial infrastructure projects. This paper proposes an assessment framework to transform unstructured online public opinions on large infrastructure projects into sentimental and topical indicators for enhancing practices of ex post evaluation and public participation. The framework uses web crawlers to collect online comments related to a large infrastructure project and employs two natural language processing technologies, including sentiment analysis and topic modeling, with spatio-temporal analysis, to transform these comments into indicators for assessing online public opinion on the project. Based on the framework, we investigate the online public opinion of the Three Gorges Project on China's largest microblogging site, namely, Weibo. Assessment results present spatial-temporal distributions of post intensity and sentiment polarity, reveals major topics with different sentiments and summarizes managerial implications, for ex post evaluation of the world's largest hydropower project. The proposed assessment framework is expected to be widely applied as a methodological strategy to assess public opinion in the ex post evaluation stage of large infrastructure projects. - Highlights: • We developed a framework to assess online public opinion on large infrastructure projects with environmental impacts. • Indicators were built to assess post intensity, sentiment polarity and major topics of the public opinion. • We took the Three Gorges Project (TGP) as an example to demonstrate the effectiveness proposed framework.

  7. Surface binding sites in carbohydrate active enzymes: An emerging picture of structural and functional diversity

    DEFF Research Database (Denmark)

    Svensson, Birte; Cockburn, Darrell

    2013-01-01

    is not universal and is in fact rare among some families of enzymes. In some cases an alternative to possessing a CBM is for the enzyme to bind to the substrate at a site on the catalytic domain, but away from the active site. Such a site is termed a surface (or secondary) binding site (SBS). SBSs have been...

  8. Three Gorges Reservoir Area: soil erosion under natural condition vs. soil erosion under current land use

    Science.gov (United States)

    Schönbrodt, Sarah; Behrens, Thorsten; Scholten, Thomas

    2010-05-01

    Apparently, the current most prominent human-induced example for large scale environmental impact is the Three Gorges Dam in China. The flooding alongside the Yangtze River, and its tributaries results in a vast loss of settlement and farmland area with productive, fertile valley soils. Due to the associated high land use dynamic on uphill-sites, the soil resources are underlying high land use pressure. Within our study, the soil erosion under natural conditions is compared to the soil erosion under current land use after the impoundment. Both were modeled using the empirical Universal Soil Loss Equation (USLE) which is able to predict long-term annual soil loss with limited data. The database consists of digital terrain data (45 m resolution DEM, erosive slope length based on Monte-Carlo-Aggregation according to Behrens et al. (2008)), field investigations of recent erosion forms, and literature studies. The natural disposition to soil erosion was calculated considering the USLE factors R, S, and K. The soil erosion under current land use was calculated taking into account all USLE factors. The study area is the catchment of the Xiangxi River in the Three Gorges Reservoir area. Within the Xiangxi Catchment (3,200 km²) the highly dynamic backwater area (580 km²), and two micro-scale study sites (Xiangjiaba with 2.8 km², and Quyuan with 88 km²) are considered more detailed as they are directly affected by the river impoundment. Central features of the Xiangxi Catchment are the subtropical monsoon climate, an extremely steep sloping relief (mean slope angle 39°, SD 22.8°) artificially fractured by farmland terraces, and a high soil erodibility (mean K factor 0.37, SD 0.13). On the catchment scale the natural disposition to soil erosion makes up to mean 518.0 t ha-1 a-1. The maximum potential soil loss of 1,730.1 t ha-1 a-1 under natural conditions is reached in the Quyuan site (mean 635.8 t ha-1 a-1) within the backwater area (mean 582.9 t ha-1 a-1). In the

  9. Potential impact of thermal effluents from Chongqing Fuling nuclear power plant to the Three Gorges Reservoir

    International Nuclear Information System (INIS)

    Han Baohua; Li Jianguo; Ma Binghui; Zhang Yue; Sun Qunli; Hu Yuping

    2012-01-01

    This study is based on the hydrological data near Chongqing Fuling Nuclear Power Plant along the Yangtze River, the present situation of the ecological environment of the Three Gorges Reservoir and the predicted results of thermal effluents from Chongqing Fuling Nuclear Power Plant. The standards of cooling water and the thermal tolerances indexes of aquatic organisms were investigated. The effects of thermal effluents on aquatic organisms were analyzed. The potential impact of Chongqing Fuling nuclear power plant to the Three Gorges Reservoir was explained. The results show that in the most adverse working conditions, the surface temperature near the outfall area is not more than 1℃, the temperature of thermal effluents do not exceed the suitable thermal range of fish breeding, growth and other thermal tolerances indexes. Thermal effluents from nuclear power plant have no influence about fish, plankton and benthic organisms in the Three Gorges Reservoir. (authors)

  10. Poisoning Experiments Aimed at Discriminating Active and Less-Active Sites of Silica-Supported Tantalum Hydride for Alkane Metathesis

    KAUST Repository

    Saggio, Guillaume; Taoufik, Mostafa; Basset, Jean-Marie; Thivolle-Cazat, Jean

    2010-01-01

    Only 50% of the silica-supported tantalum hydride sites are active in the metathesis of propane. Indeed, more than 45% of the tantalum hydride can be eliminated by a selective oxygen poisoning of inactive sites with no significant decrease

  11. Robotics and Automation Activities at the Savannah River Site: A Site Report for SUBWOG 39F

    International Nuclear Information System (INIS)

    Teese, G.D.

    1995-01-01

    The Savannah River Site has successfully used robots, teleoperators, and remote video to reduce exposure to ionizing radiation, improve worker safety, and improve the quality of operations. Previous reports have described the use of mobile teleoperators in coping with a high level liquid waste spill, the removal of highly contaminated equipment, and the inspection of nuclear reactor vessels. This report will cover recent applications at the Savannah River, as well as systems which SRS has delivered to other DOE site customers

  12. Site characterization activities at Stripa and other Swedish projects

    International Nuclear Information System (INIS)

    Ahlstroehm, P.E.

    1991-01-01

    The Swedish research programme concerning spent nuclear fuel disposal aims for submitting a siting license application around the year 2000. An important step towards that goal will be the detailed characterization of at least two potential sites in late 1990s. In preparation for such characterization several research projects are conducted. One is the international Stripa Project that includes a site characterization and validation project for a small size granite rock body. The Stripa work also includes further development of instrumentation and measurement techniques. Another project is the Finnsjoen Fracture Zone Project, which is characterizing a subhorizontal zone at depths from 100 to 350 meters. The third project is the new Swedish Hard Rock Laboratory planned at the site of the Oskarshamn nuclear power plant. The preinvestigations and construction of this laboratory include major efforts in development, application and validation of site characterization methodology. (author) 6 figs., 9 refs

  13. Using Carbohydrate Interaction Assays to Reveal Novel Binding Sites in Carbohydrate Active Enzymes

    DEFF Research Database (Denmark)

    Cockburn, Darrell; Wilkens, Casper; Dilokpimol, Adiphol

    2016-01-01

    Carbohydrate active enzymes often contain auxiliary binding sites located either on independent domains termed carbohydrate binding modules (CBMs) or as so-called surface binding sites (SBSs) on the catalytic module at a certain distance from the active site. The SBSs are usually critical...

  14. Half-of-the-sites reactivity of outer-membrane phospholipase A against an active-site-directed inhibitor.

    Science.gov (United States)

    Ubarretxena-Belandia, I; Cox, R C; Dijkman, R; Egmond, M R; Verheij, H M; Dekker, N

    1999-03-01

    The reaction of a novel active-site-directed phospholipase A1 inhibitor with the outer-membrane phospholipase A (OMPLA) was investigated. The inhibitor 1-p-nitrophenyl-octylphosphonate-2-tridecylcarbamoyl-3-et hanesulfonyl -amino-3-deoxy-sn-glycerol irreversibly inactivated OMPLA. The inhibition reaction did not require the cofactor calcium or an unprotonated active-site His142. The inhibition of the enzyme solubilized in hexadecylphosphocholine micelles was characterized by a rapid (t1/2 = 20 min) and complete loss of enzymatic activity, concurrent with the covalent modification of 50% of the active-site serines, as judged from the amount of p-nitrophenolate (PNP) released. Modification of the remaining 50% occurred at a much lower rate, indicative of half-of-the-sites reactivity against the inhibitor of this dimeric enzyme. Inhibition of monomeric OMPLA solubilized in hexadecyl-N,N-dimethyl-1-ammonio-3-propanesulfonate resulted in an equimolar monophasic release of PNP, concurrent with the loss of enzymatic activity (t1/2 = 14 min). The half-of-the-sites reactivity is discussed in view of the dimeric nature of this enzyme.

  15. Radiological survey following decontamination activities near the TA-45 site

    International Nuclear Information System (INIS)

    Gunderson, T.; Buhl, T.; Romero, R.; Salazar, J.

    1983-07-01

    Three areas at the site of a former radioactive liquid waste treatment plant at Los Alamos National Laboratory were decontaminated during 1982 by Bechtel Corporation, with health physics support provided by Eberline Instrument Corporation, under the Department of Energy's Formerly Utilized Sites Remedial Action Program (FUSRAP). Before decontamination, there were above-background concentrations of gross alpha, gross beta, 238 Pu, 239 240 Pu, 241 Am, 90 Sr, and 137 Cs in the surface soils. These combined concentrations were above operational decontamination guidelines for surface soil contamination. After cleanup operations, radionuclide concentrations in surface soils at all three sites were within decontamination guidelines

  16. Active serine involved in the stabilization of the active site loop in the Humicola lanuginosa lipase

    DEFF Research Database (Denmark)

    Peters, Günther H.j.; Svendsen, A.; Langberg, H.

    1998-01-01

    We have investigated the binding properties of and dynamics in Humicola lanuginosa lipase (HII) and the inactive mutant S146A (active Ser146 substituted with Ala) using fluorescence spectroscopy and molecular dynamics simulations, respectively. Hll and S146A show significantly different binding......, whereas only small changes are observed for I-Ill suggesting that the active site Lid in the latter opens more easily and hence more lipase molecules are bound to the liposomes. These observations are in agreement with molecular dynamics simulations and subsequent essential dynamics analyses. The results...... to substantial conformational alterations in the H. lanuginosa Lipase and different binding affinities....

  17. Disulfide bond within mu-calpain active site inhibits activity and autolysis.

    Science.gov (United States)

    Lametsch, René; Lonergan, Steven; Huff-Lonergan, Elisabeth

    2008-09-01

    Oxidative processes have the ability to influence mu-calpain activity. In the present study the influence of oxidation on activity and autolysis of mu-calpain was examined. Furthermore, LC-MS/MS analysis was employed to identify and characterize protein modifications caused by oxidation. The results revealed that the activity of mu-calpain is diminished by oxidation with H2O2 in a reversible manner involving cysteine and that the rate of autolysis of mu-calpain concomitantly slowed. The LC-MS/MS analysis of the oxidized mu-calpain revealed that the amino acid residues 105-133 contained a disulfide bond between Cys(108) and Cys(115). The finding that the active site cysteine in mu-calpain is able to form a disulfide bond has, to our knowledge, not been reported before. This could be part of a unique oxidation mechanism for mu-calpain. The results also showed that the formation of the disulfide bond is limited in the control (no oxidant added), and further limited in a concentration-dependent manner when beta-mercaptoethanol is added. However, the disulfide bond is still present to some extent in all conditions indicating that the active site cysteine is potentially highly susceptible to the formation of this intramolecular disulfide bond.

  18. Calpain 3 Is Activated through Autolysis within the Active Site and Lyses Sarcomeric and Sarcolemmal Components

    Science.gov (United States)

    Taveau, Mathieu; Bourg, Nathalie; Sillon, Guillaume; Roudaut, Carinne; Bartoli, Marc; Richard, Isabelle

    2003-01-01

    Calpain 3 (Capn3) is known as the skeletal muscle-specific member of the calpains, a family of intracellular nonlysosomal cysteine proteases. This enigmatic protease has many unique features among the calpain family and, importantly, mutations in Capn3 have been shown to be responsible for limb girdle muscular dystrophy type 2A. Here we demonstrate that the Capn3 activation mechanism is similar to the universal activation of caspases and corresponds to an autolysis within the active site of the protease. We undertook a search for substrates in immature muscle cells, as several lines of evidence suggest that Capn3 is mostly in an inactive state in muscle and needs a signal to be activated. In this model, Capn3 proteolytic activity leads to disruption of the actin cytoskeleton and disorganization of focal adhesions through cleavage of several endogenous proteins. In addition, we show that titin, a previously identified Capn3 partner, and filamin C are further substrates of Capn3. Finally, we report that Capn3 colocalizes in vivo with its substrates at various sites along cytoskeletal structures. We propose that Capn3-mediated cleavage produces an adaptive response of muscle cells to external and/or internal stimuli, establishing Capn3 as a muscle cytoskeleton regulator. PMID:14645524

  19. The Origins of the Acheulean at Olduvai Gorge (Tanzania: A New Paleoanthropological Project in East Africa

    Directory of Open Access Journals (Sweden)

    Ignacio de la Torre

    2012-12-01

    Full Text Available The disappearance of the earliest human culture, the Oldowan, and its substitution by a new technology, the Acheulean, is one of the main topics in modern Paleoanthropology. Recent research has established that the Acheulean emerged originally in East Africa around 1.7–1.6 million years ago, and from that area expanded across the rest of Africa, Europe and parts of Asia. Despite the great relevance of the Oldowan-Acheulean transition, little is known about the biological and cultural evolutionary mechanisms underlying this process. Traditionally, it has been assumed that this major cultural change was ignited by the emergence of a new human species, Homo ergaster/erectus, and that there was a steady technological evolution during the Oldowan that eventually led to the emergence of the Acheulean handaxes. However, these assumptions are not grounded in the current available evidence, but rooted in cultural-history paradigms that should now be superseded. Olduvai Gorge (Tanzania is the site where the traditional view of the Oldowan-Acheulean transition was established. The aim of the recently launched Olduvai Geochronology and Archaeology Project is to tackle this question by conducting a comprehensive research program at Olduvai, based on the retrieval of fresh data derived from new laboratory and fieldwork research. The multidisciplinary character of this ongoing study is providing an integrative perspective to the analysis of the paleoecology, archaeology, geology and geochronology of the transition to the Acheulean at Olduvai. Using an innovative theoretical perspective that combines interests in cultural change, ecological adaptations, and biological evolution, and state-of-the-art methods in archaeology, geology and taphonomy, this project aims to make Olduvai one of the world’s best references for the understanding of the evolutionary processes that led to the emergence of the Acheulean, the longest lasting culture in the history of

  20. Human population and activities in Forsmark. Site description

    Energy Technology Data Exchange (ETDEWEB)

    Miliander, Sofia; Punakivi, Mari; Kylaekorpi, Lasse; Rydgren, Bernt [SwedPower AB, Stockholm (Sweden)

    2004-12-01

    The Swedish Nuclear Fuel and Waste Management Co (SKB) is in the process of selecting a safe and environmentally acceptable location for a deep repository of radioactive waste. Two alternative locations are under investigation. These are Forsmark, Oesthammars kommun (kommun = municipality) and Simpevarp/Laxemar, Oskarshamns kommun. SKB has expressed the importance of describing the humans and their activities in these areas and therefore has this synthesis concerning the human population in Forsmark been produced.The description is a statistical synthesis, mainly based upon statistical data from SCB (Statistics Sweden) that has been collected, processed and analysed. The statistical data has not been verified through site inspections and interviews. When using statistical data, it is advisable to note that the data becomes more unreliable if the areas are small, with small populations.The data in this description is essential for future evaluations of the impact on the environment and its human population (Environmental Impact Assessments). The data is also important when modelling the potential flows of radio nuclides and calculating the risk of exposure in future safety assessments.The actual area for the study is in this report called 'the Forsmark area', an area of 19.5 km{sup 2} near Forsmark nuclear power plant. The land use in the Forsmark area differs notably from the land use in Uppsala laen (laen = county). Only 0.04% of the total area is developed (built-up) compared to 4.9% in Uppsala laen and only 4% is agricultural land compared to 25% in the county. Furthermore, there are far more forest, wetlands and water areas in the Forsmark area. The forest area represents as much as 72.5% of the total area.The Forsmark area is uninhabited, and its surroundings are very sparsely populated. In 2002, the population density in Forsmark was 1.8 inhabitants per square kilometre, which was 24 times lower than in Uppsala laen. The population density in the

  1. Human population and activities in Forsmark. Site description

    International Nuclear Information System (INIS)

    Miliander, Sofia; Punakivi, Mari; Kylaekorpi, Lasse; Rydgren, Bernt

    2004-12-01

    The Swedish Nuclear Fuel and Waste Management Co (SKB) is in the process of selecting a safe and environmentally acceptable location for a deep repository of radioactive waste. Two alternative locations are under investigation. These are Forsmark, Oesthammars kommun (kommun = municipality) and Simpevarp/Laxemar, Oskarshamns kommun. SKB has expressed the importance of describing the humans and their activities in these areas and therefore has this synthesis concerning the human population in Forsmark been produced.The description is a statistical synthesis, mainly based upon statistical data from SCB (Statistics Sweden) that has been collected, processed and analysed. The statistical data has not been verified through site inspections and interviews. When using statistical data, it is advisable to note that the data becomes more unreliable if the areas are small, with small populations.The data in this description is essential for future evaluations of the impact on the environment and its human population (Environmental Impact Assessments). The data is also important when modelling the potential flows of radio nuclides and calculating the risk of exposure in future safety assessments.The actual area for the study is in this report called 'the Forsmark area', an area of 19.5 km 2 near Forsmark nuclear power plant. The land use in the Forsmark area differs notably from the land use in Uppsala laen (laen = county). Only 0.04% of the total area is developed (built-up) compared to 4.9% in Uppsala laen and only 4% is agricultural land compared to 25% in the county. Furthermore, there are far more forest, wetlands and water areas in the Forsmark area. The forest area represents as much as 72.5% of the total area.The Forsmark area is uninhabited, and its surroundings are very sparsely populated. In 2002, the population density in Forsmark was 1.8 inhabitants per square kilometre, which was 24 times lower than in Uppsala laen. The population density in the parish has been

  2. Off-site emergency preparedness activities within the European Commission

    International Nuclear Information System (INIS)

    Kelly, G.N.

    1998-01-01

    Increasing attention is being given by the European Commission to off-site emergency preparedness as part of its broader contribution to improving nuclear safety in Eastern Europe. The main initiatives being taken or planned by the Commission in this area are summarised. Particular attention is given to two topics: Firstly, the development of the RODOS (Real-time On-line DecisiOn Support) system for supporting off-site emergency management in the event of a nuclear accident; and, secondly, the work of an Inter-Service Group on nuclear Off-Site Emergency Preparedness (OSEP) in Eastern Europe that has been established within the Commission. The contribution that each is making to improving emergency preparedness, both in Eastern Europe and in Europe more widely, is described. (orig.)

  3. Testing Proposed Correlations Between Olduvai Gorge and Laetoli, Tanzania Using Tephra Composition

    Science.gov (United States)

    McHenry, L. J.

    2006-12-01

    Olduvai Gorge and Laetoli are well-known Plio-Pleistocene archaeological sites located 30 km apart in Tanzania. Both received volcanic input from the nearby Ngorongoro Volcanic Highlands (NVH), and together provide a sedimentary and volcanic record from about 4.3 Ma to the Holocene. Previous researchers have proposed likely temporal correlations between the two sites, using both faunal and volcanic evidence. Direct tephra correlation between these sites could create a regional stratigraphic framework for their fossil and paleoecological records. Here, one of the proposed correlations is tested using geochemical fingerprinting. The fossiliferous Laetolil and Ndolanya beds of Laetoli predate the deposition of the Olduvai Beds, however recent 39Ar/40Ar SCLF age dating has shown potential temporal overlap between the Naibadad (2.23-1.93 +/- 0.02; Mangea, 1993) and Olpiro Beds (2.06-2.01 +/- 0.03; Manega 1993) at Laetoli with the Naabi Ignimbrite (2.029 +/- 0.005 Ma, Walter et al. 1992) and lower Bed I at Olduvai. Both the Naibadad bed and lower Bed I also contain fresh quartz-bearing tephra, which can be used for geochemical correlation. Three Naibadad tuffs and five lower Bed I tuffs (Naabi Ignimbrite, coarse feldspar crystal tuff (CFCT), Tuff IA, and two ignimbrites near Ngorongoro) were analyzed by electron microprobe for phenocryst and glass composition and compared to test for possible correlations. Certain mineralogical features made such a correlation unlikely. None of the lower Bed I tuffs analyzed contain significant plagioclase, which is present in all of the Naibadad tuffs analyzed. One Naibadad tuff has a bimodal glass composition indistinguishable from the CFCT, however the CFCT is rich in hornblende, while this Naibadad tuff contains none. This mineralogical difference highlights the need for mineralogical in addition to glass geochemical data for tephra correlation. Ngorongoro crater is the likely source for the Naibadad and lower Bed I tuffs because it

  4. The status of Yucca Mountain site characterization activities

    International Nuclear Information System (INIS)

    Gertz, Carl P.; Larkin, Erin L.; Hamner, Melissa

    1992-01-01

    The U.S. Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM) is continuing its studies to determine if Yucca Mountain, Nevada, can safely isolate high-level nuclear waste for the next ten thousand years. As mandated by Congress in 1987, DOE is studying the rocks, the climate, and the water table at Yucca Mountain to ensure that the site is suitable before building a repository adopt 305 meters below the surface. Yucca Mountain, located 160.9 kilometers northwest of Las Vegas, lies on the western edge of the Nevada Test Site. Nevada and DOE have been in litigation over environmental permits needed to conduct studies, but recent court decisions have allowed limited new work to begin. This paper will examine progress made on the Yucca Mountain Site Characterization Project (YMP) during 1991 and continuing into 1992, discuss the complex legal issues and describe new site drilling work. Design work on the underground exploratory studies facility (ESF) will also be discussed. (author)

  5. Molecular characterization of monoclonal antibodies that inhibit acetylcholinesterase by targeting the peripheral site and backdoor region.

    Directory of Open Access Journals (Sweden)

    Yves Bourne

    Full Text Available The inhibition properties and target sites of monoclonal antibodies (mAbs Elec403, Elec408 and Elec410, generated against Electrophorus electricus acetylcholinesterase (AChE, have been defined previously using biochemical and mutagenesis approaches. Elec403 and Elec410, which bind competitively with each other and with the peptidic toxin inhibitor fasciculin, are directed toward distinctive albeit overlapping epitopes located at the AChE peripheral anionic site, which surrounds the entrance of the active site gorge. Elec408, which is not competitive with the other two mAbs nor fasciculin, targets a second epitope located in the backdoor region, distant from the gorge entrance. To characterize the molecular determinants dictating their binding site specificity, we cloned and sequenced the mAbs; generated antigen-binding fragments (Fab retaining the parental inhibition properties; and explored their structure-function relationships using complementary x-ray crystallography, homology modeling and flexible docking approaches. Hypermutation of one Elec403 complementarity-determining region suggests occurrence of antigen-driven selection towards recognition of the AChE peripheral site. Comparative analysis of the 1.9Å-resolution structure of Fab408 and of theoretical models of its Fab403 and Fab410 congeners evidences distinctive surface topographies and anisotropic repartitions of charges, consistent with their respective target sites and inhibition properties. Finally, a validated, data-driven docking model of the Fab403-AChE complex suggests a mode of binding at the PAS that fully correlates with the functional data. This comprehensive study documents the molecular peculiarities of Fab403 and Fab410, as the largest peptidic inhibitors directed towards the peripheral site, and those of Fab408, as the first inhibitor directed toward the backdoor region of an AChE and a unique template for the design of new, specific modulators of AChE catalysis.

  6. Fire history reflects human history in the Pine Creek Gorge of north-central Pennsylvania

    Science.gov (United States)

    Patrick H. Brose; Richard P. Guyette; Joseph M. Marschall; Michael C. Stambaugh

    2015-01-01

    Fire history studies are important tools for understanding past fire regimes and the roles humans played in those regimes. Beginning in 2010, we conducted a fire history study in the Pine Creek Gorge area of north-central Pennsylvania to ascertain the number of fires and fire-free intervals, their variability through time, and the role of human influences. We collected...

  7. The Three Gorges Dam: A great leap backward for China's electricity consumers and economy

    International Nuclear Information System (INIS)

    Adams, P.; Ryder, G.

    1999-01-01

    Reasons why the Three Gorges Dam, the largest hydroelectric power project in the world, is not only an environmental disaster, but also an economically unsound undertaking for the Chinese economy are discussed. The thrust of the argument is that rapid advancement in technology, in combination with the economic reforms to decentralize electric power production in China, will allow private enterprise to be in direct competition with the Three Gorges (and other bid dam) projects. These factors, combined with the economic pressures resulting from the shutting down of money-losing state enterprises and consequently, a significant reduction in the demand for electricity, spell disaster for the big dam projects conceived during the centrally-planned, Maoist era. Because of the Three Gorges project's unusually large size, the outdated and unreliable power transmission networks in China, and because the local state transmission grids are not connected to China's national grid, the central government will have to invest some $ 30 billion over the next three years in a new national transmission grid. The aggregate result of these events will be that competition from cheaper, cleaner power producers (such as combined cycle power producers) will price the Three Gorges power out of the market by the time it is expected to go into production in 2009. Based on the assessment of reputable world economic and engineering organizations, Probe International recommends cancellation of the project to avoid environmental and economic disaster. 61 refs

  8. Phytogeographical analysis of the flora of Miljkovačka gorge in Eastern Serbia

    Directory of Open Access Journals (Sweden)

    Miljković, M.

    2012-12-01

    Full Text Available As a result of two-year investigation of the Miljkovacka gorge flora, carried out during the 2010. and 2011., 331 plant taxa belonging to 245 genera and 70 families were recorded and sorted into 112 floristic elements, 15 area groups and 9 area types. Phytogeographical analysis showed that the species of Eurasian area type are the most abundant ones.

  9. Nitrogen transport, transformation, and retention in the Three Gorges Reservoir : A mass balance approach

    NARCIS (Netherlands)

    Ran, Xiangbin; Bouwman, Lex; Yu, Zhigang; Beusen, Arthur; Chen, Hongtao; Yao, Qingzhen

    2017-01-01

    Dam construction in river systems affects the biogeochemistry of nitrogen (N), yet most studies on N cycling in reservoirs do not consider the transformations and retention of the different N species. This study addresses the N inputs, transport, transformations, and retention in the Three Gorges

  10. Linking Three Gorges Dam and downstream hydrological regimes along the Yangtze River, China

    NARCIS (Netherlands)

    Mei, X.; Dai, Z.; Van Gelder, P.H.A.J.M.; Gao, J.

    2015-01-01

    The magnitude of anthropogenic influence, especially dam regulation, on hydrological system is of scientific and practical value for large river management. As the largest dam in the world by far, Three Gorges Dam (TGD) is expected to be a strong evidence on dam impacts on downstream hydrological

  11. Spatial Forecast of Landslides in Three Gorges Based On Spatial Data Mining

    Directory of Open Access Journals (Sweden)

    Xianmin Wang

    2009-03-01

    Full Text Available The Three Gorges is a region with a very high landslide distribution density and a concentrated population. In Three Gorges there are often landslide disasters, and the potential risk of landslides is tremendous. In this paper, focusing on Three Gorges, which has a complicated landform, spatial forecasting of landslides is studied by establishing 20 forecast factors (spectra, texture, vegetation coverage, water level of reservoir, slope structure, engineering rock group, elevation, slope, aspect, etc. China-Brazil Earth Resources Satellite (Cbers images were adopted based on C4.5 decision tree to mine spatial forecast landslide criteria in Guojiaba Town (Zhigui County in Three Gorges and based on this knowledge, perform intelligent spatial landslide forecasts for Guojiaba Town. All landslides lie in the dangerous and unstable regions, so the forecast result is good. The method proposed in the paper is compared with seven other methods: IsoData, K-Means, Mahalanobis Distance, Maximum Likelihood, Minimum Distance, Parallelepiped and Information Content Model. The experimental results show that the method proposed in this paper has a high forecast precision, noticeably higher than that of the other seven methods.

  12. Spatial forecast of landslides in three gorges based on spatial data mining.

    Science.gov (United States)

    Wang, Xianmin; Niu, Ruiqing

    2009-01-01

    The Three Gorges is a region with a very high landslide distribution density and a concentrated population. In Three Gorges there are often landslide disasters, and the potential risk of landslides is tremendous. In this paper, focusing on Three Gorges, which has a complicated landform, spatial forecasting of landslides is studied by establishing 20 forecast factors (spectra, texture, vegetation coverage, water level of reservoir, slope structure, engineering rock group, elevation, slope, aspect, etc). China-Brazil Earth Resources Satellite (Cbers) images were adopted based on C4.5 decision tree to mine spatial forecast landslide criteria in Guojiaba Town (Zhigui County) in Three Gorges and based on this knowledge, perform intelligent spatial landslide forecasts for Guojiaba Town. All landslides lie in the dangerous and unstable regions, so the forecast result is good. The method proposed in the paper is compared with seven other methods: IsoData, K-Means, Mahalanobis Distance, Maximum Likelihood, Minimum Distance, Parallelepiped and Information Content Model. The experimental results show that the method proposed in this paper has a high forecast precision, noticeably higher than that of the other seven methods.

  13. Preliminary siting activities for new waste handling facilities at the Idaho National Engineering Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, D.D.; Hoskinson, R.L.; Kingsford, C.O.; Ball, L.W.

    1994-09-01

    The Idaho Waste Processing Facility, the Mixed and Low-Level Waste Treatment Facility, and the Mixed and Low-Level Waste Disposal Facility are new waste treatment, storage, and disposal facilities that have been proposed at the Idaho National Engineering Laboratory (INEL). A prime consideration in planning for such facilities is the selection of a site. Since spring of 1992, waste management personnel at the INEL have been involved in activities directed to this end. These activities have resulted in the (a) identification of generic siting criteria, considered applicable to either treatment or disposal facilities for the purpose of preliminary site evaluations and comparisons, (b) selection of six candidate locations for siting,and (c) site-specific characterization of candidate sites relative to selected siting criteria. This report describes the information gathered in the above three categories for the six candidate sites. However, a single, preferred site has not yet been identified. Such a determination requires an overall, composite ranking of the candidate sites, which accounts for the fact that the sites under consideration have different advantages and disadvantages, that no single site is superior to all the others in all the siting criteria, and that the criteria should be assigned different weighing factors depending on whether a site is to host a treatment or a disposal facility. Stakeholder input should now be solicited to help guide the final selection. This input will include (a) siting issues not already identified in the siting, work to date, and (b) relative importances of the individual siting criteria. Final site selection will not be completed until stakeholder input (from the State of Idaho, regulatory agencies, the public, etc.) in the above areas has been obtained and a strategy has been developed to make a composite ranking of all candidate sites that accounts for all the siting criteria.

  14. Preliminary siting activities for new waste handling facilities at the Idaho National Engineering Laboratory

    International Nuclear Information System (INIS)

    Taylor, D.D.; Hoskinson, R.L.; Kingsford, C.O.; Ball, L.W.

    1994-09-01

    The Idaho Waste Processing Facility, the Mixed and Low-Level Waste Treatment Facility, and the Mixed and Low-Level Waste Disposal Facility are new waste treatment, storage, and disposal facilities that have been proposed at the Idaho National Engineering Laboratory (INEL). A prime consideration in planning for such facilities is the selection of a site. Since spring of 1992, waste management personnel at the INEL have been involved in activities directed to this end. These activities have resulted in the (a) identification of generic siting criteria, considered applicable to either treatment or disposal facilities for the purpose of preliminary site evaluations and comparisons, (b) selection of six candidate locations for siting,and (c) site-specific characterization of candidate sites relative to selected siting criteria. This report describes the information gathered in the above three categories for the six candidate sites. However, a single, preferred site has not yet been identified. Such a determination requires an overall, composite ranking of the candidate sites, which accounts for the fact that the sites under consideration have different advantages and disadvantages, that no single site is superior to all the others in all the siting criteria, and that the criteria should be assigned different weighing factors depending on whether a site is to host a treatment or a disposal facility. Stakeholder input should now be solicited to help guide the final selection. This input will include (a) siting issues not already identified in the siting, work to date, and (b) relative importances of the individual siting criteria. Final site selection will not be completed until stakeholder input (from the State of Idaho, regulatory agencies, the public, etc.) in the above areas has been obtained and a strategy has been developed to make a composite ranking of all candidate sites that accounts for all the siting criteria

  15. GASS-WEB: a web server for identifying enzyme active sites based on genetic algorithms.

    Science.gov (United States)

    Moraes, João P A; Pappa, Gisele L; Pires, Douglas E V; Izidoro, Sandro C

    2017-07-03

    Enzyme active sites are important and conserved functional regions of proteins whose identification can be an invaluable step toward protein function prediction. Most of the existing methods for this task are based on active site similarity and present limitations including performing only exact matches on template residues, template size restraints, despite not being capable of finding inter-domain active sites. To fill this gap, we proposed GASS-WEB, a user-friendly web server that uses GASS (Genetic Active Site Search), a method based on an evolutionary algorithm to search for similar active sites in proteins. GASS-WEB can be used under two different scenarios: (i) given a protein of interest, to match a set of specific active site templates; or (ii) given an active site template, looking for it in a database of protein structures. The method has shown to be very effective on a range of experiments and was able to correctly identify >90% of the catalogued active sites from the Catalytic Site Atlas. It also managed to achieve a Matthew correlation coefficient of 0.63 using the Critical Assessment of protein Structure Prediction (CASP 10) dataset. In our analysis, GASS was ranking fourth among 18 methods. GASS-WEB is freely available at http://gass.unifei.edu.br/. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  16. Human population and activities at Simpevarp. Site description

    International Nuclear Information System (INIS)

    Miliander, Sofia; Punakivi, Mari; Kylaekorpi, Lasse; Rydgren, Bernt

    2004-12-01

    The Swedish Nuclear Fuel and Waste Management Co (SKB) is in the process of selecting a safe and environmentally acceptable location for a deep repository of radioactive waste. Two alternative locations are under investigation. These are Forsmark, Oesthammars kommun (kommun = municipality) and Simpevarp/Laxemar, Oskarshamns kommun. SKB has expressed the importance of describing the humans and their activities in these areas and therefore has this synthesis concerning the human population in Forsmark been produced. The description is a statistical synthesis, mainly based upon statistical data from SCB (Statistics Sweden) that has been collected, processed and analysed. The statistical data has not been verified through site inspections and interviews. When using statistical data, it is advisable to note that the data becomes more unreliable if the areas are small, with small populations. The data in this description is essential for future evaluations of the impact on the environment and its human population (environmental impacts assessments). The data is also important when modelling the potential flows of radio nuclides and calculating the risk of exposure in future safety assessments. The actual area for the study is in this report called 'the Simpevarp area', an area of 127.0 km 2 near Oskarshamn nuclear power plant. The land use in Simpevarp area differs notably from the land use in Kalmar laen. The forest area is far more dominating in Simpevarp area than in Kalmar laen and it represents as much as 89% compared to 63% of the total area. Only 4.4% of the area is arable land compared to 11.6% in Kalmar laen and only 0.3% is of other type (wetlands, bare rock, quarries, pites etc) compared to 15.6% in the county. The main observation is that Simpevarp area is a sparsely populated area located in a relatively lightly populated county. In 2002, the population density was 7.4 inhabitants/km 2 , three times lower than in Kalmar laen. The demography statistics show

  17. Human population and activities at Simpevarp. Site description

    Energy Technology Data Exchange (ETDEWEB)

    Miliander, Sofia; Punakivi, Mari; Kylaekorpi, Lasse; Rydgren, Bernt [SwedPower AB, Stockholm (Sweden)

    2004-12-01

    The Swedish Nuclear Fuel and Waste Management Co (SKB) is in the process of selecting a safe and environmentally acceptable location for a deep repository of radioactive waste. Two alternative locations are under investigation. These are Forsmark, Oesthammars kommun (kommun = municipality) and Simpevarp/Laxemar, Oskarshamns kommun. SKB has expressed the importance of describing the humans and their activities in these areas and therefore has this synthesis concerning the human population in Forsmark been produced. The description is a statistical synthesis, mainly based upon statistical data from SCB (Statistics Sweden) that has been collected, processed and analysed. The statistical data has not been verified through site inspections and interviews. When using statistical data, it is advisable to note that the data becomes more unreliable if the areas are small, with small populations. The data in this description is essential for future evaluations of the impact on the environment and its human population (environmental impacts assessments). The data is also important when modelling the potential flows of radio nuclides and calculating the risk of exposure in future safety assessments. The actual area for the study is in this report called 'the Simpevarp area', an area of 127.0 km{sup 2} near Oskarshamn nuclear power plant. The land use in Simpevarp area differs notably from the land use in Kalmar laen. The forest area is far more dominating in Simpevarp area than in Kalmar laen and it represents as much as 89% compared to 63% of the total area. Only 4.4% of the area is arable land compared to 11.6% in Kalmar laen and only 0.3% is of other type (wetlands, bare rock, quarries, pites etc) compared to 15.6% in the county. The main observation is that Simpevarp area is a sparsely populated area located in a relatively lightly populated county. In 2002, the population density was 7.4 inhabitants/km{sup 2}, three times lower than in Kalmar laen. The

  18. Early Site Permit Demonstration Program: Recommendations for communication activities and public participation in the Early Site Permit Demonstration Program

    Energy Technology Data Exchange (ETDEWEB)

    1993-01-27

    On October 24, 1992, President Bush signed into law the National Energy Policy Act of 1992. The bill is a sweeping, comprehensive overhaul of the Nation`s energy laws, the first in more than a decade. Among other provisions, the National Energy Policy Act reforms the licensing process for new nuclear power plants by adopting a new approach developed by the US Nuclear Regulatory Commission (NRC) in 1989, and upheld in court in 1992. The NRC 10 CFR Part 52 rule is a three-step process that guarantees public participation at each step. The steps are: early site permit approval; standard design certifications; and, combined construction/operating licenses for nuclear power reactors. Licensing reform increases an organization`s ability to respond to future baseload electricity generation needs with less financial risk for ratepayers and the organization. Costly delays can be avoided because design, safety and siting issues will be resolved before a company starts to build a plant. Specifically, early site permit approval allows for site suitability and acceptability issues to be addressed prior to an organization`s commitment to build a plant. Responsibility for site-specific activities, including communications and public participation, rests with those organizations selected to try out early site approval. This plan has been prepared to assist those companies (referred to as sponsoring organizations) in planning their communications and public involvement programs. It provides research findings, information and recommendations to be used by organizations as a resource and starting point in developing their own plans.

  19. Early Site Permit Demonstration Program: Recommendations for communication activities and public participation in the Early Site Permit Demonstration Program

    International Nuclear Information System (INIS)

    1993-01-01

    On October 24, 1992, President Bush signed into law the National Energy Policy Act of 1992. The bill is a sweeping, comprehensive overhaul of the Nation's energy laws, the first in more than a decade. Among other provisions, the National Energy Policy Act reforms the licensing process for new nuclear power plants by adopting a new approach developed by the US Nuclear Regulatory Commission (NRC) in 1989, and upheld in court in 1992. The NRC 10 CFR Part 52 rule is a three-step process that guarantees public participation at each step. The steps are: early site permit approval; standard design certifications; and, combined construction/operating licenses for nuclear power reactors. Licensing reform increases an organization's ability to respond to future baseload electricity generation needs with less financial risk for ratepayers and the organization. Costly delays can be avoided because design, safety and siting issues will be resolved before a company starts to build a plant. Specifically, early site permit approval allows for site suitability and acceptability issues to be addressed prior to an organization's commitment to build a plant. Responsibility for site-specific activities, including communications and public participation, rests with those organizations selected to try out early site approval. This plan has been prepared to assist those companies (referred to as sponsoring organizations) in planning their communications and public involvement programs. It provides research findings, information and recommendations to be used by organizations as a resource and starting point in developing their own plans

  20. Regional impact of climate on Japanese encephalitis in areas located near the three gorges dam.

    Directory of Open Access Journals (Sweden)

    Yuntao Bai

    Full Text Available BACKGROUND: In this study, we aim to identify key climatic factors that are associated with the transmission of Japanese encephalitis virus in areas located near the Three Gorges Dam, between 1997 and 2008. METHODS: We identified three geographical regions of Chongqing, based on their distance from the Three Gorges Dam. Collectively, the three regions consisted of 12 districts from which study information was collected. Zero-Inflated Poisson Regression models were run to identify key climatic factors of the transmission of Japanese encephalitis virus for both the whole study area and for each individual region; linear regression models were conducted to examine the fluctuation of climatic variables over time during the construction of the Three Gorges Dam. RESULTS: Between 1997 and 2008, the incidence of Japanese encephalitis decreased throughout the entire city of Chongqing, with noticeable variations taking place in 2000, 2001 and 2006. The eastern region, which is closest to the Three Gorges Dam, suffered the highest incidence of Japanese encephalitis, while the western region experienced the lowest incidence. Linear regression models revealed that there were seasonal fluctuations of climatic variables during this period. Zero-Inflated Poisson Regression models indicated a significant positive association between temperature (with a lag of 1 and 3 months and Japanese encephalitis incidence, and a significant negative association between rainfall (with a lag of 0 and 4 months and Japanese encephalitis incidence. CONCLUSION: The spatial and temporal trends of Japanese encephalitis incidence that occurred in the City of Chongqing were associated with temperature and rainfall. Seasonal fluctuations of climatic variables during this period were also observed. Additional studies that focus on long-term data collection are needed to validate the findings of this study and to further explore the effects of the Three Gorges Dam on Japanese

  1. Anoxic degradation of nitrogenous heterocyclic compounds by activated sludge and their active sites.

    Science.gov (United States)

    Xu, Peng; Han, Hongjun; Zhuang, Haifeng; Hou, Baolin; Jia, Shengyong; Wang, Dexin; Li, Kun; Zhao, Qian

    2015-05-01

    The potential for degradation of five nitrogenous heterocyclic compounds (NHCs), i.e., imidazole, pyridine, indole, quinoline, and carbazole, was investigated under anoxic conditions with acclimated activated sludge. Results showed that NHCs with initial concentration of 50 mg/L could be completely degraded within 60 hr. The degradation of five NHCs was dependent upon the chemical structures with the following sequence: imidazole>pyridine>indole>quinoline>carbazole in terms of their degradation rates. Quantitative structure-biodegradability relationship studies of the five NHCs showed that the anoxic degradation rates were correlated well with highest occupied molecular orbital. Additionally, the active sites of NHCs identified by calculation were confirmed by analysis of intermediates using gas chromatography and mass spectrometry. Copyright © 2015. Published by Elsevier B.V.

  2. Active-Site Hydration and Water Diffusion in Cytochrome P450cam: A Highly Dynamic Process

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Yinglong [ORNL; Baudry, Jerome Y [ORNL

    2011-01-01

    Long-timescale molecular dynamics simulations (300 ns) are performed on both the apo- (i.e., camphor-free) and camphor-bound cytochrome P450cam (CYP101). Water diffusion into and out of the protein active site is observed without biased sampling methods. During the course of the molecular dynamics simulation, an average of 6.4 water molecules is observed in the camphor-binding site of the apo form, compared to zero water molecules in the binding site of the substrate-bound form, in agreement with the number of water molecules observed in crystal structures of the same species. However, as many as 12 water molecules can be present at a given time in the camphor-binding region of the active site in the case of apo-P450cam, revealing a highly dynamic process for hydration of the protein active site, with water molecules exchanging rapidly with the bulk solvent. Water molecules are also found to exchange locations frequently inside the active site, preferentially clustering in regions surrounding the water molecules observed in the crystal structure. Potential-of-mean-force calculations identify thermodynamically favored trans-protein pathways for the diffusion of water molecules between the protein active site and the bulk solvent. Binding of camphor in the active site modifies the free-energy landscape of P450cam channels toward favoring the diffusion of water molecules out of the protein active site.

  3. The effects of overwinter flowson the spring condition of rainbow and brown trout size classes in the Green River downstream of Flaming Gorge Dam, Utah.

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, A. K.; LaGory, K. E.; Hayse, J. W.; Environmental Science Division

    2010-06-25

    Flaming Gorge Dam, a hydroelectric facility operated by the Bureau of Reclamation (Reclamation), is located on the Green River in Daggett County, northeastern Utah. Until recently, and since the early 1990s, single daily peak releases or steady flows have been the operational pattern of the dam during the winter period. However, releases from Flaming Gorge Reservoir followed a double-peak pattern (two daily flow peaks) during the winters of 2006-2007 and 2008-2009. Because there is little recent long-term history of double-peaking at Flaming Gorge Dam, the potential effects of double-peaking operations on trout body condition in the dam's tailwater are not known. A study plan was developed that identified research activities to evaluate potential effects from winter double-peaking operations (Hayse et al. 2009). Along with other tasks, the study plan identified the need to conduct a statistical analysis of historical trout condition and macroinvertebrate abundance to evaluate the potential effects of hydropower operations. The results from analyses based on the combined size classes of trout (85-630 mm) were presented in Magnusson et al. (2008). The results of this earlier analysis suggested possible relationships between trout condition and flow, but concern that some of the relationships resulted from size-based effects (e.g., apparent changes in condition may have been related to concomitant changes in size distribution, because small trout may have responded differently to flow than large trout) prompted additional analysis of within-size class relationships. This report presents the results of analyses of three different size classes of trout (small: 200-299 mm, medium: 300-399 mm, and large: {ge}400 mm body length). We analyzed historical data to (1) describe temporal patterns and relationships among flows, benthic macroinvertebrate abundance, and condition of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in the tailwaters of Flaming

  4. The effects of overwinter flows on the spring condition of rainbow and brown trout size classes in the Green River downstream of Flaming Gorge Dam, Utah

    International Nuclear Information System (INIS)

    Magnusson, A.K.; LaGory, K.E.; Hayse, J.W.

    2010-01-01

    Flaming Gorge Dam, a hydroelectric facility operated by the Bureau of Reclamation (Reclamation), is located on the Green River in Daggett County, northeastern Utah. Until recently, and since the early 1990s, single daily peak releases or steady flows have been the operational pattern of the dam during the winter period. However, releases from Flaming Gorge Reservoir followed a double-peak pattern (two daily flow peaks) during the winters of 2006-2007 and 2008-2009. Because there is little recent long-term history of double-peaking at Flaming Gorge Dam, the potential effects of double-peaking operations on trout body condition in the dam's tailwater are not known. A study plan was developed that identified research activities to evaluate potential effects from winter double-peaking operations (Hayse et al. 2009). Along with other tasks, the study plan identified the need to conduct a statistical analysis of historical trout condition and macroinvertebrate abundance to evaluate the potential effects of hydropower operations. The results from analyses based on the combined size classes of trout (85-630 mm) were presented in Magnusson et al. (2008). The results of this earlier analysis suggested possible relationships between trout condition and flow, but concern that some of the relationships resulted from size-based effects (e.g., apparent changes in condition may have been related to concomitant changes in size distribution, because small trout may have responded differently to flow than large trout) prompted additional analysis of within-size class relationships. This report presents the results of analyses of three different size classes of trout (small: 200-299 mm, medium: 300-399 mm, and large: (ge)400 mm body length). We analyzed historical data to (1) describe temporal patterns and relationships among flows, benthic macroinvertebrate abundance, and condition of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in the tailwaters of Flaming

  5. Assessing the Influence of the Three Gorges Dam on Hydrological Drought Using GRACE Data

    Directory of Open Access Journals (Sweden)

    Fupeng Li

    2018-05-01

    Full Text Available With worldwide economic and social development, more dams are being constructed to meet the increasing demand for hydropower, which may considerably influence hydrological drought. Here, an index named the “Dam Influence Index” (DII is proposed to assess the influence of the Three Gorges Dam (TGD on hydrological drought in the Yangtze River Basin (YRB in China. First, the total terrestrial water storage (TTWS is derived from Gravity Recovery and Climate Experiment data. Then, the natural-driven terrestrial water storage (NTWS is predicted from the soil moisture, precipitation, and temperature data based on an artificial neural network model. Finally, the DII is derived using the empirical (Kaplan-Meier cumulative distribution function of the differences between the TTWS and the NTWS. The DIIs of the three sub-basins in the YRB were 1.38, −4.66, and −7.32 between 2003 and 2008, which indicated an increase in TTWS in the upper sub-basin and a reduction in the middle and lower sub-basins. According to the results, we concluded that impoundments of the TGD between 2003 and 2008 slightly alleviated the hydrological drought in the upper sub-basin and significantly aggravated the hydrological drought in the middle and lower sub-basins, which is consistent with the Palmer Drought Severity Index. This study provides a new perspective for estimating the effects of large-scale human activities on hydrological drought and a scientific decision-making basis for the managing water resources over the operation of the TGD.

  6. Facebook, Twitter Activities Sites, Location and Students' Interest in Learning

    Science.gov (United States)

    Igbo, J. N.; Ezenwaji, Ifeyinwa; Ajuziogu, Christiana U.

    2018-01-01

    This study was carried out to ascertain the influence of social networking sites activities (twitter and Facebook) on secondary school students' interest in learning It also considered the impact of these social networking sites activities on location of the students. Two research questions and two null hypotheses guided the study. Mean and…

  7. Probing the putative active site of YjdL

    DEFF Research Database (Denmark)

    Jensen, Johanne Mørch; Ismat, Fouzia; Szakonyi, Gerda

    2012-01-01

    pocket that opens towards the extracellular space. The C-terminal side chain faces in the opposite direction into a sub pocket that faces the cytoplasm. These data indicated a stabilizing effect on a bulky N-terminal residue by an Ala281Phe variant and on the dipeptide backbone by Trp278...... with Glu388, a preliminary orientation model of a dipeptide in the YjdL cavity is presented. Single site mutations of particularly Ala281 and Trp278 support the presented orientation. A dipeptide bound in the cavity of YjdL appears to be oriented such that the N-terminal side chain protrudes into a sub...

  8. Assessment of former uranium sites and their ongoing remediation activities

    International Nuclear Information System (INIS)

    Khakimov, N.; Adkhamov, A.; Nazarov, Kh.M.; Mahmadov, T.; Mirsaidov, I.U.

    2012-01-01

    Carried out analysis on tailing's buildings operation shows that period for engineer barrier service, taking into account any catastrophic natural impacts, is too little in comparison with life-time of long-live radionuclides. Priorities should be defined by danger degree and isolation costs (protection optimization), therefore uncommon, non-traditional methods, developed taking into account natural factors for long-live waste (radionuclides) isolation are necessary. That's why, it is necessary to carry out specialized research and development, design and exploratory and other works on monitoring of social-ecological condition of these sites, as well as on demographic public diseases, living in these regions.

  9. Prediction of Active Site and Distal Residues in E. coli DNA Polymerase III alpha Polymerase Activity.

    Science.gov (United States)

    Parasuram, Ramya; Coulther, Timothy A; Hollander, Judith M; Keston-Smith, Elise; Ondrechen, Mary Jo; Beuning, Penny J

    2018-02-20

    The process of DNA replication is carried out with high efficiency and accuracy by DNA polymerases. The replicative polymerase in E. coli is DNA Pol III, which is a complex of 10 different subunits that coordinates simultaneous replication on the leading and lagging strands. The 1160-residue Pol III alpha subunit is responsible for the polymerase activity and copies DNA accurately, making one error per 10 5 nucleotide incorporations. The goal of this research is to determine the residues that contribute to the activity of the polymerase subunit. Homology modeling and the computational methods of THEMATICS and POOL were used to predict functionally important amino acid residues through their computed chemical properties. Site-directed mutagenesis and biochemical assays were used to validate these predictions. Primer extension, steady-state single-nucleotide incorporation kinetics, and thermal denaturation assays were performed to understand the contribution of these residues to the function of the polymerase. This work shows that the top 15 residues predicted by POOL, a set that includes the three previously known catalytic aspartate residues, seven remote residues, plus five previously unexplored first-layer residues, are important for function. Six previously unidentified residues, R362, D405, K553, Y686, E688, and H760, are each essential to Pol III activity; three additional residues, Y340, R390, and K758, play important roles in activity.

  10. Assessment of activation products in the Savannah River Site environment

    International Nuclear Information System (INIS)

    Carlton, W.H.; Denham, M.

    1996-07-01

    This document assesses the impact of radioactive activation products released from SRS facilities since the first reactor became operational late in 1953. The isotopes reported here are those whose release resulted in the highest dose to people living near SRS: 32 P, 51 Cr, 60 C, and 65 Zn. Release pathways, emission control features, and annual releases to the aqueous and atmospheric environments are discussed. No single incident has resulted in a major acute release of activation products to the environment. The releases were the result of normal operations of the reactors and separations facilities. Releases declined over the years as better controls were established and production was reduced. The overall radiological impact of SRS activation product atmospheric releases from 1954 through 1994 on the offsite maximally exposed individual can be characterized by a total dose of 0.76 mrem. During the same period, such an individual received a total dose of 14,400 mrem from non-SRS sources of ionizing radiation present in the environment. SRS activation product aqueous releases between 1954 and 1994 resulted in a total dose of 54 mrem to the offsite maximally exposed individual. The impact of SRS activation product releases on offsite populations also has been evaluated

  11. The landscape degradation in the mining sites with suspended activity

    Directory of Open Access Journals (Sweden)

    Anca IONCE

    2009-08-01

    Full Text Available The extracting industry, through its extraction activities, of shipping the ores, of breaking the ores, of preparing the practical substances, of stowing the useless rock, of transporting the practical substances, etc. might modify the area’s relief and the quality of ground, of thesurface waters and of the air. Suceava County has an old tradition of mining, where the results of this activity are visible, especially the visual point of view, and where not taking certain measures of ecological remediation will emphasize the disappointing image of the landscape within the areas of mining activity performing.The predominant mountainous landscape, in which mining activities have been held, is being affected also by the abandoned industrial and administrative buildings, in an advanced degradation state.The hydrographic system, very rich in mining areas, has its water quality affected by the acid rock drainage- phenomenon which appeared in many mining waste deposits.

  12. Location and activity specific site-management for military locations

    NARCIS (Netherlands)

    Maring, L.; Hulst, M. van; Meuken, D.

    2009-01-01

    pace is limited in the Netherlands and military activities, that may cause nuisance or environmental hazards, should therefore be considered and evaluated during the use of military locations. The last few years TNO and Deltares have worked on a research program on environmental effects due to

  13. Site directed mutagenesis of amino acid residues at the active site of mouse aldehyde oxidase AOX1.

    Directory of Open Access Journals (Sweden)

    Silvia Schumann

    Full Text Available Mouse aldehyde oxidase (mAOX1 forms a homodimer and belongs to the xanthine oxidase family of molybdoenzymes which are characterized by an essential equatorial sulfur ligand coordinated to the molybdenum atom. In general, mammalian AOs are characterized by broad substrate specificity and an yet obscure physiological function. To define the physiological substrates and the enzymatic characteristics of mAOX1, we established a system for the heterologous expression of the enzyme in Escherichia coli. The recombinant protein showed spectral features and a range of substrate specificity similar to the native protein purified from mouse liver. The EPR data of recombinant mAOX1 were similar to those of AO from rabbit liver, but differed from the homologous xanthine oxidoreductase enzymes. Site-directed mutagenesis of amino acids Val806, Met884 and Glu1265 at the active site resulted in a drastic decrease in the oxidation of aldehydes with no increase in the oxidation of purine substrates. The double mutant V806E/M884R and the single mutant E1265Q were catalytically inactive enzymes regardless of the aldehyde or purine substrates tested. Our results show that only Glu1265 is essential for the catalytic activity by initiating the base-catalyzed mechanism of substrate oxidation. In addition, it is concluded that the substrate specificity of molybdo-flavoenzymes is more complex and not only defined by the three characterized amino acids in the active site.

  14. Water Pollution Prediction in the Three Gorges Reservoir Area and Countermeasures for Sustainable Development of the Water Environment

    Directory of Open Access Journals (Sweden)

    Yinghui Li

    2017-10-01

    Full Text Available The Three Gorges Project was implemented in 1994 to promote sustainable water resource use and development of the water environment in the Three Gorges Reservoir Area (hereafter “Reservoir Area”. However, massive discharge of wastewater along the river threatens these goals; therefore, this study employs a grey prediction model (GM to predict the annual emissions of primary pollution sources, including industrial wastewater, domestic wastewater, and oily and domestic wastewater from ships, that influence the Three Gorges Reservoir Area water environment. First, we optimize the initial values of a traditional GM (1,1 model, and build a new GM (1,1 model that minimizes the sum of squares of the relative simulation errors. Second, we use the new GM (1,1 model to simulate historical annual emissions data for the four pollution sources and thereby test the effectiveness of the model. Third, we predict the annual emissions of the four pollution sources in the Three Gorges Reservoir Area for a future period. The prediction results reveal the annual emission trends for the major wastewater types, and indicate the primary sources of water pollution in the Three Gorges Reservoir Area. Based on our predictions, we suggest several countermeasures against water pollution and towards the sustainable development of the water environment in the Three Gorges Reservoir Area.

  15. Water Pollution Prediction in the Three Gorges Reservoir Area and Countermeasures for Sustainable Development of the Water Environment

    Science.gov (United States)

    Huang, Shuaijin; Qu, Xuexin

    2017-01-01

    The Three Gorges Project was implemented in 1994 to promote sustainable water resource use and development of the water environment in the Three Gorges Reservoir Area (hereafter “Reservoir Area”). However, massive discharge of wastewater along the river threatens these goals; therefore, this study employs a grey prediction model (GM) to predict the annual emissions of primary pollution sources, including industrial wastewater, domestic wastewater, and oily and domestic wastewater from ships, that influence the Three Gorges Reservoir Area water environment. First, we optimize the initial values of a traditional GM (1,1) model, and build a new GM (1,1) model that minimizes the sum of squares of the relative simulation errors. Second, we use the new GM (1,1) model to simulate historical annual emissions data for the four pollution sources and thereby test the effectiveness of the model. Third, we predict the annual emissions of the four pollution sources in the Three Gorges Reservoir Area for a future period. The prediction results reveal the annual emission trends for the major wastewater types, and indicate the primary sources of water pollution in the Three Gorges Reservoir Area. Based on our predictions, we suggest several countermeasures against water pollution and towards the sustainable development of the water environment in the Three Gorges Reservoir Area. PMID:29077006

  16. Water Pollution Prediction in the Three Gorges Reservoir Area and Countermeasures for Sustainable Development of the Water Environment.

    Science.gov (United States)

    Li, Yinghui; Huang, Shuaijin; Qu, Xuexin

    2017-10-27

    The Three Gorges Project was implemented in 1994 to promote sustainable water resource use and development of the water environment in the Three Gorges Reservoir Area (hereafter "Reservoir Area"). However, massive discharge of wastewater along the river threatens these goals; therefore, this study employs a grey prediction model (GM) to predict the annual emissions of primary pollution sources, including industrial wastewater, domestic wastewater, and oily and domestic wastewater from ships, that influence the Three Gorges Reservoir Area water environment. First, we optimize the initial values of a traditional GM (1,1) model, and build a new GM (1,1) model that minimizes the sum of squares of the relative simulation errors. Second, we use the new GM (1,1) model to simulate historical annual emissions data for the four pollution sources and thereby test the effectiveness of the model. Third, we predict the annual emissions of the four pollution sources in the Three Gorges Reservoir Area for a future period. The prediction results reveal the annual emission trends for the major wastewater types, and indicate the primary sources of water pollution in the Three Gorges Reservoir Area. Based on our predictions, we suggest several countermeasures against water pollution and towards the sustainable development of the water environment in the Three Gorges Reservoir Area.

  17. Rac1 GTPase activates the WAVE regulatory complex through two distinct binding sites

    Science.gov (United States)

    Brautigam, Chad A; Xing, Wenmin; Yang, Sheng; Henry, Lisa; Doolittle, Lynda K; Walz, Thomas

    2017-01-01

    The Rho GTPase Rac1 activates the WAVE regulatory complex (WRC) to drive Arp2/3 complex-mediated actin polymerization, which underpins diverse cellular processes. Here we report the structure of a WRC-Rac1 complex determined by cryo-electron microscopy. Surprisingly, Rac1 is not located at the binding site on the Sra1 subunit of the WRC previously identified by mutagenesis and biochemical data. Rather, it binds to a distinct, conserved site on the opposite end of Sra1. Biophysical and biochemical data on WRC mutants confirm that Rac1 binds to both sites, with the newly identified site having higher affinity and both sites required for WRC activation. Our data reveal that the WRC is activated by simultaneous engagement of two Rac1 molecules, suggesting a mechanism by which cells may sense the density of active Rac1 at membranes to precisely control actin assembly. PMID:28949297

  18. Molecular Basis for Enzymatic Sulfite Oxidation -- HOW THREE CONSERVED ACTIVE SITE RESIDUES SHAPE ENZYME ACTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Susan; Rapson, Trevor; Johnson-Winters, Kayunta; Astashkin, Andrei; Enemark, John; Kappler, Ulrike

    2008-11-10

    Sulfite dehydrogenases (SDHs) catalyze the oxidation and detoxification of sulfite to sulfate, a reaction critical to all forms of life. Sulfite-oxidizing enzymes contain three conserved active site amino acids (Arg-55, His-57, and Tyr-236) that are crucial for catalytic competency. Here we have studied the kinetic and structural effects of two novel and one previously reported substitution (R55M, H57A, Y236F) in these residues on SDH catalysis. Both Arg-55 and His-57 were found to have key roles in substrate binding. An R55M substitution increased Km(sulfite)(app) by 2-3 orders of magnitude, whereas His-57 was required for maintaining a high substrate affinity at low pH when the imidazole ring is fully protonated. This effect may be mediated by interactions of His-57 with Arg-55 that stabilize the position of the Arg-55 side chain or, alternatively, may reflect changes in the protonation state of sulfite. Unlike what is seen for SDHWT and SDHY236F, the catalytic turnover rates of SDHR55M and SDHH57A are relatively insensitive to pH (~;;60 and 200 s-1, respectively). On the structural level, striking kinetic effects appeared to correlate with disorder (in SDHH57A and SDHY236F) or absence of Arg-55 (SDHR55M), suggesting that Arg-55 and the hydrogen bonding interactions it engages in are crucial for substrate binding and catalysis. The structure of SDHR55M has sulfate bound at the active site, a fact that coincides with a significant increase in the inhibitory effect of sulfate in SDHR55M. Thus, Arg-55 also appears to be involved in enabling discrimination between the substrate and product in SDH.

  19. Lipolytic activity from bacteria prospected in polluted portuary sites

    Directory of Open Access Journals (Sweden)

    Kaori Levy Fonseca

    2014-06-01

    This study demonstrates that these TBT resistant isolates have, at the same time, the capacity to produce enzymes with a large biotechnological potential but, nevertheless, their relationship is not well understood, representing a novel approach. It is expected for these organisms to produce highly biotechnological relevant biocatalysts, due to their severe adaptations (Suehiro et al., 2007. The fully characterization of these lipases, mostly for F3 with elevated lipolytic activity exhibited, presents also a future challenge.

  20. Disturbance opens recruitment sites for bacterial colonization in activated sludge

    OpenAIRE

    Marr, Junko; Spear, John; Drewes, Jörg; Vuono, David

    2015-01-01

    Little is known about the role of immigration in shaping bacterial communities or the factors that may dictate success or failure of colonization by bacteria from regional species pools. To address these knowledge gaps, the influence of bacterial colonization into an ecosystem (activated sludge bioreactor) was measured through a disturbance gradient (successive decreases in the parameter solids retention time) relative to stable operational conditions. Through a DNA sequencing approach, we sh...

  1. Time Multiplexed Active Neural Probe with 1356 Parallel Recording Sites

    Directory of Open Access Journals (Sweden)

    Bogdan C. Raducanu

    2017-10-01

    Full Text Available We present a high electrode density and high channel count CMOS (complementary metal-oxide-semiconductor active neural probe containing 1344 neuron sized recording pixels (20 µm × 20 µm and 12 reference pixels (20 µm × 80 µm, densely packed on a 50 µm thick, 100 µm wide, and 8 mm long shank. The active electrodes or pixels consist of dedicated in-situ circuits for signal source amplification, which are directly located under each electrode. The probe supports the simultaneous recording of all 1356 electrodes with sufficient signal to noise ratio for typical neuroscience applications. For enhanced performance, further noise reduction can be achieved while using half of the electrodes (678. Both of these numbers considerably surpass the state-of-the art active neural probes in both electrode count and number of recording channels. The measured input referred noise in the action potential band is 12.4 µVrms, while using 678 electrodes, with just 3 µW power dissipation per pixel and 45 µW per read-out channel (including data transmission.

  2. Effects of land use patterns on stream water quality: a case study of a small-scale watershed in the Three Gorges Reservoir Area, China.

    Science.gov (United States)

    Huang, Zhilin; Han, Liyang; Zeng, Lixiong; Xiao, Wenfa; Tian, Yaowu

    2016-02-01

    In this study, we have considered the relationship between the spatial configuration of land use and water quality in the Three Gorges Reservoir Area. Using land use types, landscape metrics, and long-term water quality data, as well as statistical and spatial analysis, we determined that most water quality parameters were negatively correlated with non-wood forest and urban areas but were strongly positively correlated with the proportion of forest area. Landscape indices such as patch density, contagion, and the Shannon diversity index were able to predict some water quality indicators, but the mean shape index was not significantly related to the proportions of farmland and water in the study area. Regression relationships were stronger in spring and fall than in summer, and relationships with nitrogen were stronger than those of the other water quality parameters (R(2) > 0.80) in all three seasons. Redundancy analysis showed that declining stream water quality was closely associated with configurations of urban, agricultural, and forest areas and with landscape fragmentation (PD) caused by urbanization and agricultural activities. Thus, a rational land use plan of adjusting the land use type, controlling landscape fragmentation, and increasing the proportion of forest area would help to achieve a healthier river ecosystem in the Three Gorges Reservoir Area (TGRA).

  3. Crustal structure across the Three Gorges area of the Yangtze platform, central China, from seismic refraction/wide-angle reflection data

    Science.gov (United States)

    Zhang, Z.; Bai, Z.; Mooney, W.; Wang, C.; Chen, X.; Wang, E.; Teng, J.; Okaya, N.

    2009-01-01

    We present active-source seismic data recorded along a 300??km-long profile across the Three Gorges area of the western Yangtze platform, central China. From west to east, the profile crosses the Zigui basin, Huangling dome and Jianghan basin. The derived crustal P-wave velocity structure changes significantly across the Tongchenghe fault that lies at the transition from the Huangling dome to the Jianghan basin. West of the Tongchenghe fault, beneath the Zigui basin and the Huangling dome, we observe a ~ 42??km thick crust of relatively low average velocity (6.3-6.4??km/s). In contrast, east of the Tongchenghe fault, beneath the Jianghan basin, the crust is only 30??km thick and has a high average velocity (6.6-6.7??km/s). A west-east variation in crustal composition along the Tongchenghe fault is also inferred. West of the fault, P-wave velocities suggest a felsic composition with an intermediate layer at the base of the crust, whilst, east of the fault, felsic, intermediate, and mafic crustal layers are apparent. Our results suggest that the crust beneath the Jianghan basin has been thinned by rifting, accompanied by intrusion of the lower crust by mafic dikes and sills. The west-to-east division of the crust in the Three Gorges area coincides with first-order geophysical contrasts in gravity, topography, crustal and lithospheric thickness. ?? 2009 Elsevier B.V.

  4. Cooperative activation of cardiac transcription through myocardin bridging of paired MEF2 sites

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Courtney M. [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Hu, Jianxin [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Thomas, Reuben [Univ. of California, San Francisco, CA (United States). Gladstone Inst.; Gainous, T. Blair [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Celona, Barbara [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Sinha, Tanvi [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Dickel, Diane E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Genomics Division; Heidt, Analeah B. [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Xu, Shan-Mei [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Bruneau, Benoit G. [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Univ. of California, San Francisco, CA (United States). Gladstone Inst.; Pollard, Katherine S. [Univ. of California, San Francisco, CA (United States). Gladstone Inst.; Pennacchio, Len A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Genomics Division; Black, Brian L. [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Univ. of California, San Francisco, CA (United States). Dept. of

    2017-03-28

    Enhancers frequently contain multiple binding sites for the same transcription factor. These homotypic binding sites often exhibit synergy, whereby the transcriptional output from two or more binding sites is greater than the sum of the contributions of the individual binding sites alone. Although this phenomenon is frequently observed, the mechanistic basis for homotypic binding site synergy is poorly understood. Here in this paper, we identify a bona fide cardiac-specific Prkaa2 enhancer that is synergistically activated by homotypic MEF2 binding sites. We show that two MEF2 sites in the enhancer function cooperatively due to bridging of the MEF2C-bound sites by the SAP domain-containing co-activator protein myocardin, and we show that paired sites buffer the enhancer from integration site-dependent effects on transcription in vivo. Paired MEF2 sites are prevalent in cardiac enhancers, suggesting that this might be a common mechanism underlying synergy in the control of cardiac gene expression in vivo.

  5. Recent progress in volcanism studies: Site characterization activities for the Yucca Mountain site characterization project

    International Nuclear Information System (INIS)

    Crowe, B.M.; Valentine, G.; Morley, R.; Perry, F.V.

    1992-01-01

    Significant progress has been made on volcanism studies over the past calendar year. There are a number of major highlights from this work. Geochronology data have been obtained for the Lathrop Wells center using a range of isotopic, radiogenic, and age-calibrated methods. Initial work is encouraging but still insufficient to resolve the age of the center with confidence. Geologic mapping of the Sleeping Butte volcanic centers was completed and a report issued on the geology and chronology data. Twenty shallow trenches have been constructed in volcanic units of the Lathrop Wells volcanic center. Results of detailed studies of the trenches support a polycyclic eruptive history. New soil data from the trenches continue to support a late Pleistocene or Holocene age for many of the volcanic units at the center. Geochemical data (trace element and isotopic analysis) show that the volcanic units of the Lathrop Wells center cannot be related to one another by fractional crystallization of a single magma batch, supporting a polycyclic model of volcanism. Structural models using existing data are used to evaluate the probability of magmatic disruption of a potential repository. Several permissive models have been developed but none lead to significant differences in calculating the disruption ratio. Work was initiated on the eruptive and subsurface effects of magmatic activity on a repository. (author)

  6. Identifying high dose activities in industrial site radiography

    International Nuclear Information System (INIS)

    Heaton, B.

    2000-01-01

    Although the radiation doses received by industrial radiographers in the UK have progressively fallen over the last few years, with most now receiving less than 1 mSv/y, a few still receive, relative to the rest, much higher doses. As a percentage of all radiographers the number stays surprisingly constant from year to year. This paper describes a survey to identify the work causing these doses and suggest possible solutions. The UK Central Index of Dose Information was interrogated to identify the industrial radiography companies having staff (not necessarily the same person) with doses of greater than 5mSv/y in the last three years for which information was available. This was 15 in total. The people on the staff receiving these doses were identified and a questionnaire sent to the companies concerned requesting information about their work. A general questionnaire about the operation of the company was also included. With the agreement of the company these questionnaires were followed up by a visit to the company to interviews a number of the management and the radiographers if available. Both groups were generally very open about their problems and every discussion had a positive outcome. Several areas of work/reasons for the doses have been identified. These are: pipeline radiography, ultra sound radiographers working on nuclear reactors, complex plant work often with several teams in the area, inability to retreat from the wind out equipment due to height or access problems, site pressure to not follow the best practices and a lack of appreciation when a dose was being received or, alternatively, carelessness. Some o these problem areas are very difficult to resolve. However ways in which the Health and Safety can help influence the doses have been identified together with practical suggestions radiographers could adopt. These will be reported. (author)

  7. Essential histidyl residues at the active site(s) of sucrose-phosphate synthase from Prosopis juliflora.

    Science.gov (United States)

    Sinha, A K; Pathre, U V; Sane, P V

    1998-11-10

    Chemical modification of sucrose-phosphate synthase (EC 2.4.1.14) from Prosopis juliflora by diethyl pyrocarbonate (DEP) and photo-oxidation in the presence of rose bengal (RB) which modify the histidyl residues of the protein resulted in the inactivation of the enzyme activity. This inactivation was dependent on the concentration of the modifying reagent and the time of incubation and followed pseudo-first order kinetics. For both the reagents, the inactivation was maximum at pH 7.5, which is consistent with the involvement and presence of histidine residues at the active site of the enzyme. Substrates, UDPG and F6P protected the enzyme against the inactivation by the modifying reagents suggesting that the histidine residues may be involved in the binding of these substrates and are essential for the catalytic activity. Specificity of DEP was indicated by an increase in absorbance at 240 nm along with concomitant inactivation of the enzyme and reactivation of the modified enzyme by hydroxylamine. These results strongly suggest the presence of histidine residue(s) at or near the active site of the enzyme.

  8. Reduction of Urease Activity by Interaction with the Flap Covering the Active Site

    Science.gov (United States)

    Macomber, Lee; Minkara, Mona S.; Hausinger, Robert P.; Merz, Kenneth M.

    2015-01-01

    With the increasing appreciation for the human microbiome coupled with the global rise of antibiotic resistant organisms, it is imperative that new methods be developed to specifically target pathogens. To that end, a novel computational approach was devised to identify compounds that reduce the activity of urease, a medically important enzyme of Helicobacter pylori, Proteus mirabilis, and many other microorganisms. Urease contains a flexible loop that covers its active site; Glide was used to identify small molecules predicted to lock this loop in an open conformation. These compounds were screened against the model urease from Klebsiella aerogenes and the natural products epigallocatechin and quercetin were shown to inhibit at low and high micromolar concentrations, respectively. These molecules exhibit a strong time-dependent inactivation of urease that was not due to their oxygen sensitivity. Rather, these compounds appear to inactivate urease by reacting with a specific Cys residue located on the flexible loop. Substitution of this cysteine by alanine in the C319A variant increased the urease resistance to both epigallocatechin and quercetin, as predicted by the computational studies. Protein dynamics are integral to the function of many enzymes; thus, identification of compounds that lock an enzyme into a single conformation presents a useful approach to define potential inhibitors. PMID:25594724

  9. Legal study on water environmental protection of Three Gorges Reservoir Area

    Institute of Scientific and Technical Information of China (English)

    DENG He

    2007-01-01

    Water environment security of the Three Gorges Reservoir Area has become a more extensive concern since the impoundment of the reservoir. This paper describes the existing water environmental hazards and defects in current legal system for water environmental protection in this area, and also discusses their possible causes and potential problems in the future based on first hand materials and other literature. According to the theories of integrated river basin management and environmental equity principle, legal proposals are put forward, which include building an unitary legal system dedicated to the Reservoir Area, setting up a basin authority of the Yangtze River to preside over the resources protection and development, using interests' compensation system to solve interest conflicts among different reaches, and making concrete regulations to direct public participation in water environmental security protection of the Three Gorges Reservoir Area.

  10. Application of a Sediment Information System to the Three Gorges Project on Yangtze River, China

    Science.gov (United States)

    Cao, Shuyou; Liu, Xingnian; Yang, Kejun; Li, Changzhi

    Based on survey and analysis of a huge number of observed entrance sediment transport data and the research results of physical and numerical modeling of Three Gorges Reservoir on the Yangtze River, a sediment information system was designed. The basis of this system includes spatial data and properties of geographic elements, and various documents involved to the Three Gorges Project (TGP). Database and knowledge base are constructed as the information bank. The running environment is constructed by the general control program to realize requirements about various sediment information. The system chooses the window software as the system software. The techniques of graphical user interfaces and groupware geographic information system are applied in this system. In this phase, the emphases of the system are development of document system, map system, and presentation system. Cross-section system of the TGP was also attached. For further improvement of the system, a prepared interface of decision supporting subsystem is finished.

  11. [A survey on ecological environment of wild Adiantum reniforme var. sinense in Three Gorges Reservoir region].

    Science.gov (United States)

    Xie, Zhong-de; Jia, Han; Fu, Shao-Zhi; Gao, Wen-Yuan; Zhang, Zhi-Wei; Sun, Wei

    2017-11-01

    The study aims at investigating the ecological environment Adiantum reniforme var. sinense of in Three Gorges Reservoir region, and providing a reference basis for the protection of resources and artificial cultivation of A. reniforme var. sinense. By using the method of investigation, field survey and experimental analysis, the vegetation, natural geographical environment, climate, soil nutrients of A. reniforme var. sinense were studied and analyzed. The survey found that A. reniforme var. sinense distribution area reduced fast in Three Gorges region, a lot of distribution has diminished and vanished due to excessive digging, currently only in 3 towns of Wanzhou there exist 4 wild distribution areas. The growth of A. reniforme var. sinense needs an environment with low altitude, steep slope and thin soil, northeast slope, canopy height and warm and humid climate characteristics, and the soil in distribution has the characteristics of high organic matter, available nitrogen, available potassium, and low available phosphorus content. Copyright© by the Chinese Pharmaceutical Association.

  12. Variation among early Homo crania from Olduvai Gorge and the Koobi Fora region.

    Science.gov (United States)

    Rightmire, G P

    1993-01-01

    Fossils recognized as early Homo were discovered first at Olduvai Gorge in 1959 and 1960. Teeth, skull parts and hand bones representing three individuals were found in Bed I, and more material followed from Bed I and lower Bed II. By 1964, L.S.B. Leakey, P.V. Tobias, and J.R. Napier were ready to name Homo habilis. But almost as soon as they had, there was confusion over the hypodigm of the new species. Tobias himself suggested that OH 13 resembles Homo erectus from Java, and he noted that OH 16 has teeth as large as those of Australopithecus. By the early 1970s, however, Tobias had put these thoughts behind him and returned to the opinion that all of the Olduvai remains are Homo habilis. At about this time, important discoveries began to flow from the Koobi Fora region in Kenya. To most observers, crania such as KNM-ER 1470 confirmed the presence of Homo in East Africa at an early date. Some of the other specimens were problematical. A.C. Walker and R.E. Leakey raised the possibility that larger skulls including KNM-ER 1470 differ significantly from smaller-brained, small-toothed individuals such as KNM-ER 1813. Other workers emphasized that there are differences of shape as well as size among the hominids from Koobi Fora. There is now substantial support for the view that in the Turkana and perhaps also in the Olduvai assemblages, there is more variation than would be expected among male and female conspecifics. One way to approach this question of sorting would be to compare all of the new fossils against the original material from Olduvai which was used to characterize Homo habilis in 1964. A problem is that the Olduvai remains are fragmentary, and none of them provides much information about vault form or facial structure. An alternative is to work first with the better crania, even if these are from other sites. I have elected to treat KNM-ER 1470 and KNM-ER 1813 as key individuals. Comparisons are based on discrete anatomy and measurements. Metric results

  13. Bull Trout Population Assessment in the Columbia River Gorge : Annual Report 2000.

    Energy Technology Data Exchange (ETDEWEB)

    Byrne, Jim; McPeak, Ron

    2001-02-01

    We summarized existing knowledge regarding the known distribution of bull trout (Salvelinus confluentus) across four sub-basins in the Columbia River Gorge in Washington. The Wind River, Little White Salmon River, White Salmon River, and the Klickitat River sub-basins were analyzed. Cold water is essential to the survival, spawning, and rearing of bull trout. We analyzed existing temperature data, installed Onset temperature loggers in the areas of the four sub-basins where data was not available, and determined that mean daily water temperatures were <15 C and appropriate for spawning and rearing of bull trout. We snorkel surveyed more than 74 km (46.25 mi.) of rivers and streams in the four sub-basins (13.8 km at night and 60.2 km during the day) and found that night snorkeling was superior to day snorkeling for locating bull trout. Surveys incorporated the Draft Interim Protocol for Determining Bull Trout Presence (Peterson et al. In Press). However, due to access and safety issues, we were unable to randomly select sample sites nor use block nets as recommended. Additionally, we also implemented the Bull Trout/Dolly Varden sampling methodology described in Bonar et al. (1997). No bull trout were found in the Wind River, Little White Salmon, or White Salmon River sub-basins. We found bull trout in the West Fork Klickitat drainage of the Klickitat River Sub-basin. Bull trout averaged 6.7 fish/100m{sup 2} in Trappers Creek, 2.6 fish/100m{sup 2} on Clearwater Creek, and 0.4 fish/100m{sup 2} in Little Muddy Creek. Bull trout was the only species of salmonid encountered in Trappers Creek and dominated in Clearwater Creek. Little Muddy Creek was the only creek where bull trout and introduced brook trout occurred together. We found bull trout only at night and typically in low flow regimes. A single fish, believed to be a bull trout x brook trout hybrid, was observed in the Little Muddy Creek. Additional surveys are needed in the West Fork Klickitat and mainstem

  14. Bull trout population assessment in the Columbia River Gorge/annual report fy2000; ANNUAL

    International Nuclear Information System (INIS)

    Byrne, Jim; McPeak, Ron

    2001-01-01

    We summarized existing knowledge regarding the known distribution of bull trout (Salvelinus confluentus) across four sub-basins in the Columbia River Gorge in Washington. The Wind River, Little White Salmon River, White Salmon River, and the Klickitat River sub-basins were analyzed. Cold water is essential to the survival, spawning, and rearing of bull trout. We analyzed existing temperature data, installed Onset temperature loggers in the areas of the four sub-basins where data was not available, and determined that mean daily water temperatures were and lt;15 C and appropriate for spawning and rearing of bull trout. We snorkel surveyed more than 74 km (46.25 mi.) of rivers and streams in the four sub-basins (13.8 km at night and 60.2 km during the day) and found that night snorkeling was superior to day snorkeling for locating bull trout. Surveys incorporated the Draft Interim Protocol for Determining Bull Trout Presence (Peterson et al. In Press). However, due to access and safety issues, we were unable to randomly select sample sites nor use block nets as recommended. Additionally, we also implemented the Bull Trout/Dolly Varden sampling methodology described in Bonar et al. (1997). No bull trout were found in the Wind River, Little White Salmon, or White Salmon River sub-basins. We found bull trout in the West Fork Klickitat drainage of the Klickitat River Sub-basin. Bull trout averaged 6.7 fish/100m(sup 2) in Trappers Creek, 2.6 fish/100m(sup 2) on Clearwater Creek, and 0.4 fish/100m(sup 2) in Little Muddy Creek. Bull trout was the only species of salmonid encountered in Trappers Creek and dominated in Clearwater Creek. Little Muddy Creek was the only creek where bull trout and introduced brook trout occurred together. We found bull trout only at night and typically in low flow regimes. A single fish, believed to be a bull trout x brook trout hybrid, was observed in the Little Muddy Creek. Additional surveys are needed in the West Fork Klickitat and mainstem

  15. Introduction to Envirocare of Utah's low activity radioactive waste disposal site located at Clive, Utah

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    Envirocare of Utah was licensed by the state of Utah on February 2, 1988, to become fully operational to receive low-activity radioactive waste at its disposal site near Clive, Utah. This paper discusses the organization of the firm, political support, acceptable materials, benefits of the operation, site characteristics, construction, health physics program, and environmental program

  16. Neutron activation analysis to the profile surface sediments from several sites on the Havana Bay

    International Nuclear Information System (INIS)

    Diaz Riso, O.; Gelen, A.; Lopez, N.; Gonzalez, H.; Manso, M.V.; Graciano, A.M.; Nogueira, C.A.; Beltran, J.; Soto, J.

    2003-01-01

    Instrumental neutron activation analysis (INAA) technique was employed to analyze the surface sediments from several sites on the Havana Bay, Cuba. Measurements of heavy and trace elements in the sediments are reported. The results show that the concentration of the elements is site dependent. The data suggest that an anthropogenic input into the bay from domestic sewage and industries occurred

  17. Computation and experiment results of the grounding model of Three Gorges Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Wen Xishan; Zhang Yuanfang; Yu Jianhui; Chen Cixuan [Wuhan University of Hydraulic and Electrical Engineering (China); Qin Liming; Xu Jun; Shu Lianfu [Yangtze River Water Resources Commission, Wuhan (China)

    1999-07-01

    A model for the computation of the grounding parameters of the grids of Three Gorges Power Plant (TGPP) on the Yangtze River is presented in this paper. Using this model computation and analysis of grounding grids is carried out. The results show that reinforcing the grid of the dam is the main body of current dissipation. It must be reliably welded to form a good grounding grid. The experimental results show that the method and program of the computations are correct. (UK)

  18. Assessing soil heavy metal pollution in the water-level-fluctuation zone of the Three Gorges Reservoir, China.

    Science.gov (United States)

    Ye, Chen; Li, Siyue; Zhang, Yulong; Zhang, Quanfa

    2011-07-15

    The water-level-fluctuation zone (WLFZ) between the elevations of 145-175 m in China's Three Gorges Reservoir has experienced a novel hydrological regime with half a year (May-September) exposed in summer and another half (October-April) submerged in winter. In September 2008 (before submergence) and June 2009 (after submergence), soil samples were collected in 12 sites in the WLFZ and heavy metals (Hg, As, Cr, Cd, Pb, Cu, Zn, Fe, and Mn) were determined. Enrichment factor (EF), factor analysis (FA), and factor analysis-multiple linear regression (FA-MLR) were employed for heavy metal pollution assessment, source identification, and source apportionment, respectively. Results demonstrate spatial variability in heavy metals before and after submergence and elements of As, Cd, Pb, Cu, and Zn are higher in the upper and low reaches. FA and FA-MLR reveal that As and Cd are the primary pollutants before submergence, and over 45% of As originates from domestic sewage and 59% of Cd from industrial wastes. After submergence, the major contaminants are Hg, Cd, and Pb, and traffic exhaust contributes approximately 81% to Hg and industrial effluent accounts about 36% and 73% for Cd and Pb, respectively. Our results suggest that increased shipping and industrial wastes have deposited large amounts of heavy metals which have been accumulated in the WLFZ during submergence period. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. 1993 annual report of hazardous waste activities for the Oak Ridge K-25 site

    Energy Technology Data Exchange (ETDEWEB)

    1994-02-01

    This report is a detailed listing of all of the Hazardous Waste activities occurring at Martin Marietta`s K-25 site. Contained herein are hazardous waste notification forms, waste stream reports, generator fee forms and various TSDR reports.

  20. 1993 annual report of hazardous waste activities for the Oak Ridge K-25 site

    International Nuclear Information System (INIS)

    1994-02-01

    This report is a detailed listing of all of the Hazardous Waste activities occurring at Martin Marietta's K-25 site. Contained herein are hazardous waste notification forms, waste stream reports, generator fee forms and various TSDR reports

  1. Urban Panorama Tourism Planning A View From River Tour Course In Post-Three Gorges Era

    Directory of Open Access Journals (Sweden)

    Wei Jia Tian

    2012-12-01

    Full Text Available The upstream cities of Yangtze River have been witnessing significant transforming since the beginning of the construction of the Three Gorges hydroelectric dam project. Chongqing Port Authority had its opportunity to alternate the river tourism strategy from being the upstream terminal of the golden route into creating a particular cruise course towards perceiving the panorama of continuous elevation of mountainous city, at the same time, promoting the renovation of the urban design so as to revival the typical mountain-river vista. This paper bases on the panoramic research of Chongqing peninsula; discusses the characteristic aspects of the three-dimension sightseeing of the mountainous city on the cruise route, which widely exists in the Three Gorges region as well. And this method is different from the two dimensional approach of skyline analysis which is more suitable for the topographic area. The achieved work can offer the tourism-related sectors a sustainable assistance to deal with “tourbanism” topics in the urban regeneration process in the Three Gorges regions.

  2. Recovery of the Three-Gorges Reservoir Impoundment Signal from ICESat altimetry and GRACE

    Science.gov (United States)

    Carabajal, C. C.; Boy, J.; Luthcke, S. B.; Harding, D. J.; Rowlands, D. D.; Lemoine, F. G.

    2006-12-01

    The Three Gorges Dam along the Yangtze River in China is one of the largest dams in the world. The water impoundment of the Three-Gorges Reservoir started in June 2003, and the volume of water will continuously increase up to about 40 km3 in 2009, over a length of about 600 km. Although water-level changes along the Yangtze River and the Three Gorges Reservoir are measured by in situ water gauges, access to these data can be quite difficult. Estimates of inland water height and extent can also be recovered from altimetry measurements performed from satellite platforms, such as those acquired by the Geoscience laser Altimetry System (GLAS) on board the Ice, Cloud and Land Elevation Satellite (ICESat). ICESat has produced a comprehensive, highly precise, set of along-track elevation measurements, every three months since its launch in 2003, which intersect the Yangtze River along its East-West extent. In addition, the water impoundment of major artificial reservoirs induces variations of global geodetic quantities, such as the gravity field and Earth rotation (Chao, 1995, Boy & Chao, 2002). Water level changes within the reservoir are compared to GRACE (Gravity Recovery And Climate Experiment) recovered water mass changes. In addition, we compare the GRACE observations of mass change in the Yangtze region to hydrological changes computed from different global soil-moisture and snow models, such as GLDAS (Global Land Data Assimilation System).

  3. Anisotropic Covalency Contributions to Superexchange Pathways in Type One Copper Active Sites

    Science.gov (United States)

    2015-01-01

    Type one (T1) Cu sites deliver electrons to catalytic Cu active sites: the mononuclear type two (T2) Cu site in nitrite reductases (NiRs) and the trinuclear Cu cluster in the multicopper oxidases (MCOs). The T1 Cu and the remote catalytic sites are connected via a Cys-His intramolecular electron-transfer (ET) bridge, which contains two potential ET pathways: P1 through the protein backbone and P2 through the H-bond between the Cys and the His. The high covalency of the T1 Cu–S(Cys) bond is shown here to activate the T1 Cu site for hole superexchange via occupied valence orbitals of the bridge. This covalency-activated electronic coupling (HDA) facilitates long-range ET through both pathways. These pathways can be selectively activated depending on the geometric and electronic structure of the T1 Cu site and thus the anisotropic covalency of the T1 Cu–S(Cys) bond. In NiRs, blue (π-type) T1 sites utilize P1 and green (σ-type) T1 sites utilize P2, with P2 being more efficient. Comparing the MCOs to NiRs, the second-sphere environment changes the conformation of the Cys-His pathway, which selectively activates HDA for superexchange by blue π sites for efficient turnover in catalysis. These studies show that a given protein bridge, here Cys-His, provides different superexchange pathways and electronic couplings depending on the anisotropic covalencies of the donor and acceptor metal sites. PMID:25310460

  4. Poisoning Experiments Aimed at Discriminating Active and Less-Active Sites of Silica-Supported Tantalum Hydride for Alkane Metathesis

    KAUST Repository

    Saggio, Guillaume

    2010-10-04

    Only 50% of the silica-supported tantalum hydride sites are active in the metathesis of propane. Indeed, more than 45% of the tantalum hydride can be eliminated by a selective oxygen poisoning of inactive sites with no significant decrease in the global turnover. Conversely, cyclopentane induces no such selective poisoning. Hence, the active tantalum hydride sites that show greater resistance to oxygen poisoning correspond to the νTa-H bands of higher wavenumbers, particularly that at 1860cm-1. These active tantalum hydride sites should correspond to tris- or monohydride species relatively far from silica surface oxygen atoms. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Concept for calculating dose rates from activated groundwater at accelerator sites

    CERN Document Server

    Prolingheuer, N; Vanderborght, J; Schlögl, B; Nabbi, R; Moormann, R

    Licensing of particle accelerators requires the proof that the groundwater outside of the site will not be significantly contaminated by activation products formed below accelerator and target. In order to reduce the effort for this proof, a site independent simplified but conservative method is under development. The conventional approach for calculation of activation of soil and groundwater is shortly described on example of a site close to Forschungszentrum Juelich, Germany. Additionally an updated overview of a data library for partition coefficients for relevant nuclides transported in the aquifer at the site is presented. The approximate model for transport of nuclides with ground water including exemplary results on nuclide concentrations outside of the site boundary and of resulting effective doses is described. Further applications and developments are finally outlined.

  6. Functional characterization of autophosphorylation sites of the activated insulin receptor-tyrosine kinase

    International Nuclear Information System (INIS)

    Flores-Riveros, J.R.; Lane, M.D.

    1987-01-01

    Insulin receptor, solubilized from 3T3-L1 cellular membranes and then purified, was autophosphorylated with [γ- 32 P]ATP in the absence or presence of insulin. Specific phosphopeptides generated by trypsin digestion of the 32 P-labeled β-subunit were identified and separated by reverse phase HPLC. In the absence of insulin, radioactivity of the phosphopeptides is evenly distributed among four major peaks designated as sites I, II, III and IV, according to their order of elution. This pattern is maintained for at least the first 30 min of autophosphorylation. When the reaction is carried out in the presence of insulin, > 50% of the total 32 P radioactivity is found in site I and the rate of 32 P incorporation into this site is markedly higher than into sites II, III and IV. Maximal activation of tyrosine kinase activity, as estimated by substrate phosphorylation, is coincident with the nearly complete phosphorylation of site I. Delayed activation of previously autophosphorylated receptor by insulin, but not by EGF or IGF-I, produced a similar pattern where phosphorylated site I predominates. These observations indicate that one major insulin-regulated autophosphorylation site in the β-subunit is responsible for activation of the insulin receptor tyrosine kinase. The isolation of this phosphopeptide on a preparative scale and its characterization are now in progress

  7. Molecular dynamics explorations of active site structure in designed and evolved enzymes.

    Science.gov (United States)

    Osuna, Sílvia; Jiménez-Osés, Gonzalo; Noey, Elizabeth L; Houk, K N

    2015-04-21

    This Account describes the use of molecular dynamics (MD) simulations to reveal how mutations alter the structure and organization of enzyme active sites. As proposed by Pauling about 70 years ago and elaborated by many others since then, biocatalysis is efficient when functional groups in the active site of an enzyme are in optimal positions for transition state stabilization. Changes in mechanism and covalent interactions are often critical parts of enzyme catalysis. We describe our explorations of the dynamical preorganization of active sites using MD, studying the fluctuations between active and inactive conformations normally concealed to static crystallography. MD shows how the various arrangements of active site residues influence the free energy of the transition state and relates the populations of the catalytic conformational ensemble to the enzyme activity. This Account is organized around three case studies from our laboratory. We first describe the importance of dynamics in evaluating a series of computationally designed and experimentally evolved enzymes for the Kemp elimination, a popular subject in the enzyme design field. We find that the dynamics of the active site is influenced not only by the original sequence design and subsequent mutations but also by the nature of the ligand present in the active site. In the second example, we show how microsecond MD has been used to uncover the role of remote mutations in the active site dynamics and catalysis of a transesterase, LovD. This enzyme was evolved by Tang at UCLA and Codexis, Inc., and is a useful commercial catalyst for the production of the drug simvastatin. X-ray analysis of inactive and active mutants did not reveal differences in the active sites, but relatively long time scale MD in solution showed that the active site of the wild-type enzyme preorganizes only upon binding of the acyl carrier protein (ACP) that delivers the natural acyl group to the active site. In the absence of bound ACP

  8. The status of siting activities for a low level waste repository in the Philippines

    International Nuclear Information System (INIS)

    Valdezco, E.M.; Visitacion, M.; Palattao, B.; Marcelo, E.A.; Venida, L.L.

    2001-01-01

    The process of site selection for a low level waste repository was initiated in 1976 when the Philippine Government decided to go nuclear and constructed the first Philippine Nuclear Power Plant in the Bataan Peninsula. However, all siting activities were suspended when the nuclear power plant was mothballed and the final decision was made to convert the plant into a combined cycle power plant. In 1995, an inter-agency committee was created under the Nuclear Power Steering Committee and mandated to conduct studies on siting of radioactive waste disposal facilities, and at the same time, perform R and D activities in support of the project. This paper describes the various siting activities carried out to date. (author)

  9. What Motivates Young Adults to Talk About Physical Activity on Social Network Sites?

    Science.gov (United States)

    Zhang, Ni; Campo, Shelly; Yang, Jingzhen; Eckler, Petya; Snetselaar, Linda; Janz, Kathleen; Leary, Emily

    2017-06-22

    Electronic word-of-mouth on social network sites has been used successfully in marketing. In social marketing, electronic word-of-mouth about products as health behaviors has the potential to be more effective and reach more young adults than health education through traditional mass media. However, little is known about what motivates people to actively initiate electronic word-of-mouth about health behaviors on their personal pages or profiles on social network sites, thus potentially reaching all their contacts on those sites. This study filled the gap by applying a marketing theoretical model to explore the factors associated with electronic word-of-mouth on social network sites about leisure-time physical activity. A Web survey link was sent to undergraduate students at one of the Midwestern universities and 439 of them completed the survey. The average age of the 439 participants was 19 years (SD=1 year, range: 18-24). Results suggested that emotional engagement with leisure-time physical activity (ie, affective involvement in leisure-time physical activity) predicted providing relevant opinions or information on social network sites. Social network site users who perceived stronger ties with all their contacts were more likely to provide and seek leisure-time physical activity opinions and information. People who provided leisure-time physical activity opinions and information were more likely to seek opinions and information, and people who forwarded information about leisure-time physical activity were more likely to chat about it. This study shed light on the application of the electronic word-of-mouth theoretical framework in promoting health behaviors. The findings can also guide the development of future social marketing interventions using social network sites to promote leisure-time physical activity. ©Ni Zhang, Shelly Campo, Jingzhen Yang, Petya Eckler, Linda Snetselaar, Kathleen Janz, Emily Leary. Originally published in the Journal of Medical

  10. 75 FR 71677 - Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Science.gov (United States)

    2010-11-24

    ... DEPARTMENT OF ENERGY Reimbursement for Costs of Remedial Action at Active Uranium and Thorium... in FY 2011 from eligible active uranium and thorium processing site licensees for reimbursement under... approximately $24.3 million of Recovery Act funds available for reimbursement in FY 2011, as well as the $10...

  11. Effects of resource activities upon repository siting and waste containment with reference to bedded salt

    International Nuclear Information System (INIS)

    Ashby, J.; Rowe, J.

    1980-02-01

    The primary consideration for the suitability of a nuclear waste repository site is the overall ability of the repository to safely contain radioactive waste. This report is a discussion of the past, present, and future effects of resource activities on waste containment. Past and present resource activities which provide release pathways (i.e., leaky boreholes, adjacent mines) will receive initial evaluation during the early stages of any repository site study. However, other resource activities which may have subtle effects on containment (e.g., long-term pumping causing increased groundwater gradients, invasion of saline water causing lower retardation) and all potential future resource activities must also be considered during the site evaluation process. Resource activities will affect both the siting and the designing of repositories. Ideally, sites should be located in areas of low resource activity and low potential for future activity, and repository design should seek to eliminate or minimize the adverse effects of any resource activity. Buffer zones should be created to provide areas in which resource activities that might adversely affect containment can be restricted or curtailed. This could mean removing large areas of land from resource development. The impact of these frozen assets should be assessed in terms of their economic value and of their effect upon resource reserves. This step could require a major effort in data acquisition and analysis followed by extensive numerical modeling of regional fluid flow and mass transport. Numerical models should be used to assess the effects of resource activity upon containment and should include the cumulative effects of different resource activities. Analysis by other methods is probably not possible except for relatively simple cases

  12. Hydrogenation active sites of unsupported molybdenum sulfide catalysts for hydroprocessing heavy oils

    Energy Technology Data Exchange (ETDEWEB)

    Iwata, Y.; Araki, Y.; Honna, K. [Tsukuba-branch, Advanced Catalyst Research Laboratory, Petroleum Energy Center, 1-1 Higashi, Tsukuba, 305-8565 Ibaraki (Japan); Miki, Y.; Sato, K.; Shimada, H. [National Institute of Materials and Chemical Research, 1-1 Higashi, Tsukuba, 305-8565 Ibaraki (Japan)

    2001-02-20

    The purpose of the present study was to elucidate the nature of the hydrogenation active sites on unsupported molybdenum sulfide catalysts, aimed at the improvement of the catalysts for the slurry processes. The number of hydrogenation active sites was found to relate to the 'inflection' on the basal plane of the catalyst particles. The comparison of the catalytic activity to that of an oil-soluble catalyst in the hydroprocessing of heavy oils suggests that the performance of the oil-soluble catalyst was near the maximum, unless another component such as Ni or Co was incorporated.

  13. Cyanide does more to inhibit heme enzymes, than merely serving as an active-site ligand

    Energy Technology Data Exchange (ETDEWEB)

    Parashar, Abhinav [Center for Biomedical Research, VIT University, Vellore, Tamil Nadu, 632014 India (India); Venkatachalam, Avanthika [REDOx Lab, PSG Institute of Advanced Studies, Avinashi Road, Peelamedu, Coimbatore, Tamil Nadu, 641004 (India); Gideon, Daniel Andrew [Center for Biomedical Research, VIT University, Vellore, Tamil Nadu, 632014 India (India); Manoj, Kelath Murali, E-mail: satyamjayatu@yahoo.com [REDOx Lab, PSG Institute of Advanced Studies, Avinashi Road, Peelamedu, Coimbatore, Tamil Nadu, 641004 (India)

    2014-12-12

    Highlights: • Cyanide (CN) is a well-studied toxic principle, known to inhibit heme-enzymes. • Inhibition is supposed to result from CN binding at the active site as a ligand. • Diverse heme enzymes’ CN inhibition profiles challenge prevailing mechanism. • Poor binding efficiency of CN at low enzyme concentrations and ligand pressures. • CN-based diffusible radicals cause ‘non-productive electron transfers’ (inhibition). - Abstract: The toxicity of cyanide is hitherto attributed to its ability to bind to heme proteins’ active site and thereby inhibit their activity. It is shown herein that the long-held interpretation is inadequate to explain several observations in heme-enzyme reaction systems. Generation of cyanide-based diffusible radicals in heme-enzyme reaction milieu could shunt electron transfers (by non-active site processes), and thus be detrimental to the efficiency of oxidative outcomes.

  14. Enhancement in catalytic activity of Aspergillus niger XynB by selective site-directed mutagenesis of active site amino acids.

    Science.gov (United States)

    Wu, Xiuyun; Tian, Zhennan; Jiang, Xukai; Zhang, Qun; Wang, Lushan

    2018-01-01

    XynB from Aspergillus niger ATCC1015 (AnXynB) is a mesophilic glycoside hydrolase (GH) family 11 xylanase which holds great potentials in a wide variety of industrial applications. In the present study, the catalytic activity and stability of AnXynB were improved by a combination of computational and experimental approaches. Virtual mutation and molecular dynamics simulations indicated that the introduction of Glu and Asn altered the interaction network at the - 3 subsite. Interestingly, the double mutant S41N/T43E displayed 72% increase in catalytic activity when compared to the wild type (WT). In addition, it also showed a better thermostability than the WT enzyme. Kinetic determination of the T43E and S41N/T43E mutants suggested that the higher xylanase activity is probably due to the increasing binding affinity of enzyme and substrate. Consequently, the enzyme activity and thermostability of AnXynB was both increased by selective site-directed mutagenesis at the - 3 subsite of its active site architecture which provides a good example for a successfully engineered enzyme for potential industrial application. Moreover, the molecular evolution approach adopted in this study led to the design of a library of sequences that captures a meaningful functional diversity in a limited number of protein variants.

  15. Thermodynamic compensation upon binding to exosite 1 and the active site of thrombin.

    Science.gov (United States)

    Treuheit, Nicholas A; Beach, Muneera A; Komives, Elizabeth A

    2011-05-31

    Several lines of experimental evidence including amide exchange and NMR suggest that ligands binding to thrombin cause reduced backbone dynamics. Binding of the covalent inhibitor dPhe-Pro-Arg chloromethyl ketone to the active site serine, as well as noncovalent binding of a fragment of the regulatory protein, thrombomodulin, to exosite 1 on the back side of the thrombin molecule both cause reduced dynamics. However, the reduced dynamics do not appear to be accompanied by significant conformational changes. In addition, binding of ligands to the active site does not change the affinity of thrombomodulin fragments binding to exosite 1; however, the thermodynamic coupling between exosite 1 and the active site has not been fully explored. We present isothermal titration calorimetry experiments that probe changes in enthalpy and entropy upon formation of binary ligand complexes. The approach relies on stringent thrombin preparation methods and on the use of dansyl-l-arginine-(3-methyl-1,5-pantanediyl)amide and a DNA aptamer as ligands with ideal thermodynamic signatures for binding to the active site and to exosite 1. Using this approach, the binding thermodynamic signatures of each ligand alone as well as the binding signatures of each ligand when the other binding site was occupied were measured. Different exosite 1 ligands with widely varied thermodynamic signatures cause a similar reduction in ΔH and a concomitantly lower entropy cost upon DAPA binding at the active site. The results suggest a general phenomenon of enthalpy-entropy compensation consistent with reduction of dynamics/increased folding of thrombin upon ligand binding to either the active site or exosite 1.

  16. Large zinc cation occupancy of octahedral sites in mechanically activated zinc ferrite powders

    International Nuclear Information System (INIS)

    Oliver, S. A.; Harris, V. G.; Hamdeh, H. H.; Ho, J. C.

    2000-01-01

    The cation site occupancy of a mechanically activated nanocrystalline zinc ferrite powder was determined as (Zn 0.55 2+ Fe 0.18 3+ ) tet [Zr 0.45 2+ Fe 1.82 3+ ] oct O 4 through analysis of extended x-ray absorption fine structure measurements, showing a large redistribution of cations between sites compared to normal zinc ferrite samples. The overpopulation of cations in the octahedral sites was attributed to the ascendance in importance of the ionic radii over the crystal energy and bonding coordination in determining which interstitial sites are occupied in this structurally disordered powder. Slight changes are observed in the local atomic environment about the zinc cations, but not the iron cations, with respect to the spinel structure. The presence of Fe 3+ on both sites is consistent with the measured room temperature magnetic properties. (c) 2000 American Institute of Physics

  17. Evaluation of physical activity web sites for use of behavior change theories.

    Science.gov (United States)

    Doshi, Amol; Patrick, Kevin; Sallis, James F; Calfas, Karen

    2003-01-01

    Physical activity (PA) Web sites were assessed for their use of behavior change theories, including constructs of the health belief model, Transtheoretical Model, social cognitive theory, and the theory of reasoned action and planned behavior. An evaluation template for assessing PA Web sites was developed, and content validity and interrater reliability were demonstrated. Two independent raters evaluated 24 PA Web sites. Web sites varied widely in application of theory-based constructs, ranging from 5 to 48 on a 100-point scale. The most common intervention strategies were general information, social support, and realistic goal areas. Coverage of theory-based strategies was low, varying from 26% for social cognitive theory to 39% for health belief model. Overall, PA Web sites provided little assessment, feedback, or individually tailored assistance for users. They were unable to substantially tailor the on-line experience for users at different stages of change or different demographic characteristics.

  18. Active sites of ligand-protected Au25 nanoparticle catalysts for CO2 electroreduction to CO

    Science.gov (United States)

    Alfonso, Dominic R.; Kauffman, Douglas; Matranga, Christopher

    2016-05-01

    Recent experimental studies have reported the electrochemical reduction of carbon dioxide (CO2) into CO at atomically precise negatively charged Au25- nanoclusters. The studies showed CO2 conversion at remarkably low overpotentials, but the exact mechanisms and nature of the active sites remain unclear. We used first-principles density functional theory and continuum solvation models to examine the role of the cluster during electrochemical CO2 reduction and analyze the free energies of proposed intermediate species. Contrary to previous assumptions, our results show that the fully ligand protected cluster is not an active CO2 reduction catalyst because formation of the crucial carboxyl intermediate required very high electrochemical potentials. Instead, our calculations suggest that the reduction process likely occurs on a dethiolated gold site, and adsorbed carboxyl intermediate formation was significantly stabilized at dethiolated gold sites. These findings point to the crucial role of exposed metal sites during electrochemical CO2 reduction at gold nanocluster catalysts.

  19. In silico analysis of Pycnoporus cinnabarinus laccase active site with toxic industrial dyes.

    Science.gov (United States)

    Prasad, Nirmal K; Vindal, Vaibhav; Narayana, Siva Lakshmi; Ramakrishna, V; Kunal, Swaraj Priyaranjan; Srinivas, M

    2012-05-01

    Laccases belong to multicopper oxidases, a widespread class of enzymes implicated in many oxidative functions in various industrial oxidative processes like production of fine chemicals to bioremediation of contaminated soil and water. In order to understand the mechanisms of substrate binding and interaction between substrates and Pycnoporus cinnabarinus laccase, a homology model was generated. The resulted model was further validated and used for docking studies with toxic industrial dyes- acid blue 74, reactive black 5 and reactive blue 19. Interactions of chemical mediators with the laccase was also examined. The docking analysis showed that the active site always cannot accommodate the dye molecules, due to constricted nature of the active site pocket and steric hindrance of the residues whereas mediators are relatively small and can easily be accommodated into the active site pocket, which, thereafter leads to the productive binding. The binding properties of these compounds along with identification of critical active site residues can be used for further site-directed mutagenesis experiments in order to identify their role in activity and substrate specificity, ultimately leading to improved mutants for degradation of these toxic compounds.

  20. A simplified method for active-site titration of lipases immobilised on hydrophobic supports.

    Science.gov (United States)

    Nalder, Tim D; Kurtovic, Ivan; Barrow, Colin J; Marshall, Susan N

    2018-06-01

    The aim of this work was to develop a simple and accurate protocol to measure the functional active site concentration of lipases immobilised on highly hydrophobic supports. We used the potent lipase inhibitor methyl 4-methylumbelliferyl hexylphosphonate to titrate the active sites of Candida rugosa lipase (CrL) bound to three highly hydrophobic supports: octadecyl methacrylate (C18), divinylbenzene crosslinked methacrylate (DVB) and styrene. The method uses correction curves to take into account the binding of the fluorophore (4-methylumbelliferone, 4-MU) by the support materials. We showed that the uptake of the detection agent by the three supports is not linear relative to the weight of the resin, and that the uptake occurs in an equilibrium that is independent of the total fluorophore concentration. Furthermore, the percentage of bound fluorophore varied among the supports, with 50 mg of C18 and styrene resins binding approximately 64 and 94%, respectively. When the uptake of 4-MU was calculated and corrected for, the total 4-MU released via inhibition (i.e. the concentration of functional lipase active sites) could be determined via a linear relationship between immobilised lipase weight and total inhibition. It was found that the functional active site concentration of immobilised CrL varied greatly among different hydrophobic supports, with 56% for C18, compared with 14% for DVB. The described method is a simple and robust approach to measuring functional active site concentration in immobilised lipase samples. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Sedimentary and hydrological studies of the Holocene palaeofloods in the Shanxi-Shaanxi Gorge of the middle Yellow River, China

    Science.gov (United States)

    Li, Xiaogang; Huang, Chun Chang; Pang, Jiangli; Zha, Xiaochun; Ma, Yugai

    2015-01-01

    Holocene slackwater deposits along the river channels were used to study the magnitude and frequency of the palaeofloods that occurred prior to gauged and historical data sets all over the world. Palaeohydrological investigations along the Shanxi-Shaanxi Gorge of the middle Yellow River, China, identified palaeoflood slackwater deposits (SWDs) at several sites along the cliffs bordering the river channel. The SWDs are intercalated within Holocene eolian loess-soil profiles and clastic slope deposits. The palaeoflood SWDs were differentiated from eolian loess and soil by the sedimentary criteria and analytical results including magnetic susceptibility and particle-size distribution, similar to the flood SWDs in 2012, which indicated that these well-sorted palaeoflood SWD beds were deposited from the suspended sediment load in floodwaters. They have recorded the extraordinary palaeoflood events which occurred between 3200 and 3000 a BP as dated by the optically stimulated luminescence method in combination with pedostratigraphic correlations with the previously studied Holocene pedo-stratigraphy in the Yellow River drainage basin. Manning slope-area calculations estimate the peak discharged for these palaeoflood events to range from 43,290 to 49,830 m3/s. The drainage area of the study site is 489,900 km2. It is 2.0-2.5 times the largest gauged flood (21,000 m3/s) that has ever occurred since 1934. These events also occurred on Yellow River tributaries, including the Weihe, Jinghe and Qishuihe Rivers. These flood events are therefore considered to be a regional expression of known climatic events in the northern hemisphere and demonstrate Holocene climatic instability. This study provides important data in understanding the interactions between regional hydro-climatic systems and global change in semiarid and subhumid regions.

  2. Risks due to industrial activities and to transports around nuclear installations sites

    International Nuclear Information System (INIS)

    Doumenc, A.; Faure, J.

    1988-01-01

    In order to verify that the human activities around a site under consideration are not incompatible with the installation conception, they should be analyzed before the definitive site selection, then watched over and if necessary limited during the installation construction and operation. Taking account of the aggression sources diversity, there is to consider different distances according to the risks. 6 tabs., 5 refs. (F.M.)

  3. [Study on species and distribution of flora of national rare and endangered medicinal plant in the Three Gorges area].

    Science.gov (United States)

    Chen, Shao-Cheng

    2013-04-01

    According to the China Plant Red Data Book and National Key Protected Wild Plants, the distribution of the rare and endangered plants and national conservative plants in the Three Gorges area were investigated and statistically analyzed. Its floristic composition and characteristics of geographical distribution were explored. As a result, a total of 97 species of medicinal flora belonging to rare and endangered national protection plants were found in the Three Gorges area. They come from 81 genera of 46 families. Their vertical distribution is obvious and horizontal distribution has discontinuous overlap. There are many ancient relict medicinal plants in the Three Gorges area. These medicinal plants have obvious temperate characteristics, and are easily found at warm and moist ravines and hillsides; The proportion of tree is much higher than that of herb, vine, shrub and fern. Most of them belong to specific and monotypic genera.

  4. Understanding Which Residues of the Active Site and Loop Structure of a Tyrosine Aminomutase Define Its Mutase and Lyase Activities.

    Science.gov (United States)

    Attanayake, Gayanthi; Walter, Tyler; Walker, Kevin D

    2018-05-30

    Site-directed mutations and substrate analogues were used to gain insights into the branch-point reaction of the 3,5-dihydro-5-methylidene-4 H-imidazol-4-one (MIO)-tyrosine aminomutase from Oryza sativa ( OsTAM). Exchanging the active residues of OsTAM (Y125C/N446K) for those in a phenylalanine aminomutase TcPAM altered its substrate specificity from tyrosine to phenylalanine. The aminomutase mechanism of OsTAM surprisingly changed almost exclusively to that of an ammonia lyase making cinnamic acid (>95%) over β-phenylalanine [Walter, T., et al. (2016) Biochemistry 55, 3497-3503]. We hypothesized that the missing electronics or sterics on the aryl ring of the phenylalanine substrate, compared with the sizable electron-donating hydroxyl of the natural tyrosine substrate, influenced the unexpected lyase reactivity of the OsTAM mutant. The double mutant was incubated with 16 α-phenylalanine substituent analogues of varying electronic strengths and sterics. The mutant converted each analogue principally to its acrylate with ∼50% conversion of the p-Br substrate, making only a small amount of the β-amino acid. The inner loop structure over the entrance to the active site was also mutated to assess how the lyase and mutase activities are affected. An OsTAM loop mutant, matching the loop residues of TcPAM, still chiefly made >95% of the acrylate from each substrate. A combined active site:loop mutant was most reactive but remained a lyase, making 10-fold more acrylates than other mutants did. While mutations within the active site changed the substrate specificity of OsTAM, continued exploration is needed to fully understand the interplay among the inner loop, the substrate, and the active site in defining the mutase and lyase activities.

  5. Active site of tripeptidyl peptidase II from human erythrocytes is of the subtilisin type

    Energy Technology Data Exchange (ETDEWEB)

    Tomkinson, B.; Wernstedt, C.; Hellman, U.; Zetterqvist, Oe.

    1987-11-01

    The present report presents evidence that the amino acid sequence around the serine of the active site of human tripeptidyl peptidase II is of the subtilisin type. The enzyme from human erythrocytes was covalently labeled at its active site with (/sup 3/H)diisopropyl fluorophosphate, and the protein was subsequently reduced, alkylated, and digested with trypsin. The labeled tryptic peptides were purified by gel filtration and repeated reversed-phase HPLC, and their amino-terminal sequences were determined. Residue 9 contained the radioactive label and was, therefore, considered to be the active serine residue. The primary structure of the part of the active site (residues 1-10) containing this residue was concluded to be Xaa-Thr-Gln-Leu-Met-Asx-Gly-Thr-Ser-Met. This amino acid sequence is homologous to the sequence surrounding the active serine of the microbial peptidases subtilisin and thermitase. These data demonstrate that human tripeptidyl peptidase II represents a potentially distinct class of human peptidases and raise the question of an evolutionary relationship between the active site of a mammalian peptidase and that of the subtilisin family of serine peptidases.

  6. Improving the neutral phytase activity from Bacillus amyloliquefaciens DSM 1061 by site-directed mutagenesis.

    Science.gov (United States)

    Xu, Wei; Shao, Rong; Wang, Zupeng; Yan, Xiuhua

    2015-03-01

    Neutral phytase is used as a feed additive for degradation of anti-nutritional phytate in aquatic feed industry. Site-directed mutagenesis of Bacillus amyloliquefaciens DSM 1061 phytase was performed with an aim to increase its activity. Mutation residues were chosen based on multiple sequence alignments and structure analysis of neutral phytsaes from different microorganisms. The mutation sites on surface (D148E, S197E and N156E) and around the active site (D52E) of phytase were selected. Analysis of the phytase variants showed that the specific activities of mutants D148E and S197E remarkably increased by about 35 and 13% over a temperature range of 40-75 °C at pH 7.0, respectively. The k cat of mutants D148E and S197E were 1.50 and 1.25 times than that of the wild-type phytase, respectively. Both D148E and S197E showed much higher thermostability than that of the wild-type phytase. However, mutants N156E and D52E led to significant loss of specific activity of the enzyme. Structural analysis revealed that these mutations may affect conformation of the active site of phytase. The present mutant phytases D148E and S197E with increased activities and thermostabilities have application potential as additives in aquaculture feed.

  7. Fragment-based identification of determinants of conformational and spectroscopic change at the ricin active site

    Directory of Open Access Journals (Sweden)

    Soares Alexei S

    2007-11-01

    Full Text Available Abstract Background Ricin is a potent toxin and known bioterrorism threat with no available antidote. The ricin A-chain (RTA acts enzymatically to cleave a specific adenine base from ribosomal RNA, thereby blocking translation. To understand better the relationship between ligand binding and RTA active site conformational change, we used a fragment-based approach to find a minimal set of bonding interactions able to induce rearrangements in critical side-chain positions. Results We found that the smallest ligand stabilizing an open conformer of the RTA active site pocket was an amide group, bound weakly by only a few hydrogen bonds to the protein. Complexes with small amide-containing molecules also revealed a switch in geometry from a parallel towards a splayed arrangement of an arginine-tryptophan cation-pi interaction that was associated with an increase and red-shift in tryptophan fluorescence upon ligand binding. Using the observed fluorescence signal, we determined the thermodynamic changes of adenine binding to the RTA active site, as well as the site-specific binding of urea. Urea binding had a favorable enthalpy change and unfavorable entropy change, with a ΔH of -13 ± 2 kJ/mol and a ΔS of -0.04 ± 0.01 kJ/(K*mol. The side-chain position of residue Tyr80 in a complex with adenine was found not to involve as large an overlap of rings with the purine as previously considered, suggesting a smaller role for aromatic stacking at the RTA active site. Conclusion We found that amide ligands can bind weakly but specifically to the ricin active site, producing significant shifts in positions of the critical active site residues Arg180 and Tyr80. These results indicate that fragment-based drug discovery methods are capable of identifying minimal bonding determinants of active-site side-chain rearrangements and the mechanistic origins of spectroscopic shifts. Our results suggest that tryptophan fluorescence provides a sensitive probe for the

  8. Threatened and endangered wildlife species of the Hanford Site related to CERCLA characterization activities

    Energy Technology Data Exchange (ETDEWEB)

    Fitzner, R.E. [Pacific Northwest Lab., Richland, WA (United States); Weiss, S.G.; Stegen, J.A. [Westinghouse Hanford Co., Richland, WA (United States)

    1994-06-01

    The US Department of Energy`s (DOE) Hanford Site has been placed on the National Priorities List, which requires that it be remediated under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) or Superfund. Potentially contaminated areas of the Hanford Site were grouped into operable units, and detailed characterization and investigation plans were formulated. The DOE Richland Operations Office requested Westinghouse Hanford Company (WHC) to conduct a biological assessment of the potential impact of these characterization activities on the threatened, endangered, and sensitive wildlife species of the Hanford Site. Additional direction for WHC compliances with wildlife protection can be found in the Environmental Compliance Manual. This document is intended to meet these requirements, in part, for the CERCLA characterization activities, as well as for other work comparable in scope. This report documents the biological assessment and describes the pertinent components of the Hanford Site as well as the planned characterization activities. Also provided are accounts of endangered, threatened, and federal candidate wildlife species on the Hanford Site and information as to how human disturbances can affect these species. Potential effects of the characterization activities are described with recommendations for mitigation measures.

  9. Testing the applicability of rapid on-site enzymatic activity detection for surface water monitoring

    Science.gov (United States)

    Stadler, Philipp; Vogl, Wolfgang; Juri, Koschelnik; Markus, Epp; Maximilian, Lackner; Markus, Oismüller; Monika, Kumpan; Peter, Strauss; Regina, Sommer; Gabriela, Ryzinska-Paier; Farnleitner Andreas, H.; Matthias, Zessner

    2015-04-01

    On-site detection of enzymatic activities has been suggested as a rapid surrogate for microbiological pollution monitoring of water resources (e.g. using glucuronidases, galactosidases, esterases). Due to the possible short measuring intervals enzymatic methods have high potential as near-real time water quality monitoring tools. This presentation describes results from a long termed field test. For twelve months, two ColiMinder devices (Vienna Water Monitoring, Austria) for on-site determination of enzymatic activity were tested for stream water monitoring at the experimental catchment HOAL (Hydrological Open Air Laboratory, Center for Water Resource Systems, Vienna University of Technology). The devices were overall able to follow and reflect the diverse hydrological and microbiological conditions of the monitored stream during the test period. Continuous data in high temporal resolution captured the course of enzymatic activity in stream water during diverse rainfall events. The method also proofed sensitive enough to determine diurnal fluctuations of enzymatic activity in stream water during dry periods. The method was able to capture a seasonal trend of enzymatic activity in stream water that matches the results gained from Colilert18 analysis for E. coli and coliform bacteria of monthly grab samples. Furthermore the comparison of ColiMinder data with measurements gained at the same test site with devices using the same method but having different construction design (BACTcontrol, microLAN) showed consistent measuring results. Comparative analysis showed significant differences between measured enzymatic activity (modified fishman units and pmol/min/100ml) and cultivation based analyses (most probable number, colony forming unit). Methods of enzymatic activity measures are capable to detect ideally the enzymatic activity caused by all active target bacteria members, including VBNC (viable but nonculturable) while cultivation based methods cannot detect VBNC

  10. SABER: a computational method for identifying active sites for new reactions.

    Science.gov (United States)

    Nosrati, Geoffrey R; Houk, K N

    2012-05-01

    A software suite, SABER (Selection of Active/Binding sites for Enzyme Redesign), has been developed for the analysis of atomic geometries in protein structures, using a geometric hashing algorithm (Barker and Thornton, Bioinformatics 2003;19:1644-1649). SABER is used to explore the Protein Data Bank (PDB) to locate proteins with a specific 3D arrangement of catalytic groups to identify active sites that might be redesigned to catalyze new reactions. As a proof-of-principle test, SABER was used to identify enzymes that have the same catalytic group arrangement present in o-succinyl benzoate synthase (OSBS). Among the highest-scoring scaffolds identified by the SABER search for enzymes with the same catalytic group arrangement as OSBS were L-Ala D/L-Glu epimerase (AEE) and muconate lactonizing enzyme II (MLE), both of which have been redesigned to become effective OSBS catalysts, demonstrated by experiments. Next, we used SABER to search for naturally existing active sites in the PDB with catalytic groups similar to those present in the designed Kemp elimination enzyme KE07. From over 2000 geometric matches to the KE07 active site, SABER identified 23 matches that corresponded to residues from known active sites. The best of these matches, with a 0.28 Å catalytic atom RMSD to KE07, was then redesigned to be compatible with the Kemp elimination using RosettaDesign. We also used SABER to search for potential Kemp eliminases using a theozyme predicted to provide a greater rate acceleration than the active site of KE07, and used Rosetta to create a design based on the proteins identified. Copyright © 2012 The Protein Society.

  11. Utility experiences in redevelopment of formerly used sites -- Wisconsin Electric's risk management and economic development activities

    International Nuclear Information System (INIS)

    Borofka, B.P.

    1999-01-01

    Wisconsin Electric Power Company, which recently celebrated its 100th anniversary, has actively promoted the redevelopment of its former sites as well as those of its customers. Serving Milwaukee and southeast Wisconsin, Wisconsin Electric's (WE) sites include former power plants, landfills, right-of-ways, and manufactured gas plant sites. In setting an example for others, as well as seeking to maximize the economic value of these sites, WE has either redeveloped or promoted the redevelopment of these sites by others. Examples include the East Wells Power Plant (now home of the Milwaukee Repertory Theater), the Lakeside Power Plant Site (now the home of Harnischfeger Corporation's headquarters), and the Commerce Street Power Plant located on the Milwaukee River near downtown Milwaukee. In each case the company evaluated the potential environmental liabilities against the unrealized asset value derived from facility location, site size, architectural uniqueness, or other characteristics. At the Commerce Street Power Plant, walking distance to the downtown Milwaukee business district combined with river frontage, were significant site values leveraged against a $5 million asbestos and lead-based paint removal project done to prepare the plant for marketing. More recently, WE has used its experience in promoting the redevelopment of the Menomonee River Valley, the original core of Milwaukee's industrial community, and in advancing a more practical regulatory approach to redeveloping older sites. Finally, the company is working with a non-profit community health clinic, community groups and local foundations in linking these redevelopment activities with the economic and physical health of inner city residents

  12. Grafting on nuclear tracks using the active sites that remain after the etching process

    International Nuclear Information System (INIS)

    Mazzei, R.; Bermudez, G. Garcia; Chappa, V.C.; Grosso, M.F. del; Fernandez, A.

    2006-01-01

    Poly(propylene) foils were irradiated with Ag ions and then chemically etched to produce samples with structured surfaces. After the etching procedure the active sites that remain on the latent track were used to graft acrylic acid. Nuclear tracks before grafting were visualised using a transmission electron microscope. The grafting yields were determined by weight measurements as a function of ion fluence, etching and grafting time, and were also analysed using Fourier transform infrared spectroscopy. Both measurements suggest that the acrylic acid was grafted on etched tracks using the active sites produced by the swift heavy ion beam

  13. Grafting on nuclear tracks using the active sites that remain after the etching process

    Energy Technology Data Exchange (ETDEWEB)

    Mazzei, R. [Unidad de Aplicaciones Tecnologicas y Agropecuarias, CNEA, 1429 Buenos Aires (Argentina) and Universidad Tecnologica Nacional, Buenos Aires (Argentina)]. E-mail: mazzei@cae.cnea.gov.ar; Bermudez, G. Garcia [U. A. de Fisica, Tandar, CNEA, 1429 Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, UNSAM, 1653 Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Chappa, V.C. [U. A. de Fisica, Tandar, CNEA, 1429 Buenos Aires (Argentina); Grosso, M.F. del [U. A. de Fisica, Tandar, CNEA, 1429 Buenos Aires (Argentina); U. A. de Materiales, CNEA, 1429 Buenos Aires (Argentina); Fernandez, A. [Universidad Tecnologica Nacional, Buenos Aires (Argentina)

    2006-09-15

    Poly(propylene) foils were irradiated with Ag ions and then chemically etched to produce samples with structured surfaces. After the etching procedure the active sites that remain on the latent track were used to graft acrylic acid. Nuclear tracks before grafting were visualised using a transmission electron microscope. The grafting yields were determined by weight measurements as a function of ion fluence, etching and grafting time, and were also analysed using Fourier transform infrared spectroscopy. Both measurements suggest that the acrylic acid was grafted on etched tracks using the active sites produced by the swift heavy ion beam.

  14. Spatiotemporal Variations of Extreme Precipitation under a Changing Climate in the Three Gorges Reservoir Area (TGRA

    Directory of Open Access Journals (Sweden)

    Mingquan Lü

    2018-01-01

    Full Text Available The Three Gorges Dam (TGD is one of the largest hydroelectric projects in the world. Monitoring the spatiotemporal distribution of extreme precipitation offers valuable information for adaptation and mitigation strategies and reservoir management schemes. This study examined variations in extreme precipitation over the Three Gorges Reservoir area (TGRA in China to investigate the potential role of climate warming and Three Gorges Reservoir (TGR. The trends in extreme precipitation over the TGRA were investigated using the iterative-based Mann–Kendall (MK test and Sen’s slope estimator, based on weather station daily data series and TRMM (Tropical Rainfall Measuring Mission data series. The mean and density distribution of extreme precipitation indices between pre-dam and post-dam, pre-1985 and post-1985, and near and distant reservoir area were assessed by the Mann–Whitney test and the Kolmogorov–Smirnov test. The ratio of extreme precipitation to non-extreme precipitation became larger. The precipitation was characterized by increases in heavy precipitation as well as decreases in light and moderate rain. Comparing extreme precipitation indices between pre-1985 (cooling and post-1985 (warming indicated extreme precipitation has changed to become heavier. Under climate warming, the precipitation amount corresponding to more than the 95th percentile increased at the rate of 6.48%/°C. Results from comparing extreme precipitation for the pre- and post-dam, near reservoir area (NRA and away from the reservoir area (ARA imply an insignificant role of the TGR on rainfall extremes over the TGRA. Moreover, the impoundment of TGR did not exert detectable impacts on the surface relative humidity (RH and water vapor pressure (WP.

  15. Orthogonal use of a human tRNA synthetase active site to achieve multi-functionality

    Science.gov (United States)

    Zhou, Quansheng; Kapoor, Mili; Guo, Min; Belani, Rajesh; Xu, Xiaoling; Kiosses, William B.; Hanan, Melanie; Park, Chulho; Armour, Eva; Do, Minh-Ha; Nangle, Leslie A.; Schimmel, Paul; Yang, Xiang-Lei

    2011-01-01

    Protein multi-functionality is an emerging explanation for the complexity of higher organisms. In this regard, while aminoacyl tRNA synthetases catalyze amino acid activation for protein synthesis, some also act in pathways for inflammation, angiogenesis, and apoptosis. How multiple functions evolved and their relationship to the active site is not clear. Here structural modeling analysis, mutagenesis, and cell-based functional studies show that the potent angiostatic, natural fragment of human TrpRS associates via Trp side chains that protrude from the cognate cellular receptor VE-cadherin. Modeling indicates that (I prefer the way it was because the conclusion was reached not only by modeling, but more so by experimental studies.)VE-cadherin Trp side chains fit into the Trp-specific active site of the synthetase. Thus, specific side chains of the receptor mimic (?) amino acid substrates and expand the functionality of the active site of the synthetase. We propose that orthogonal use of the same active site may be a general way to develop multi-functionality of human tRNA synthetases and other proteins. PMID:20010843

  16. Orthogonal use of a human tRNA synthetase active site to achieve multifunctionality.

    Science.gov (United States)

    Zhou, Quansheng; Kapoor, Mili; Guo, Min; Belani, Rajesh; Xu, Xiaoling; Kiosses, William B; Hanan, Melanie; Park, Chulho; Armour, Eva; Do, Minh-Ha; Nangle, Leslie A; Schimmel, Paul; Yang, Xiang-Lei

    2010-01-01

    Protein multifunctionality is an emerging explanation for the complexity of higher organisms. In this regard, aminoacyl tRNA synthetases catalyze amino acid activation for protein synthesis, but some also act in pathways for inflammation, angiogenesis and apoptosis. It is unclear how these multiple functions evolved and how they relate to the active site. Here structural modeling analysis, mutagenesis and cell-based functional studies show that the potent angiostatic, natural fragment of human tryptophanyl-tRNA synthetase (TrpRS) associates via tryptophan side chains that protrude from its cognate cellular receptor vascular endothelial cadherin (VE-cadherin). VE-cadherin's tryptophan side chains fit into the tryptophan-specific active site of the synthetase. Thus, specific side chains of the receptor mimic amino acid substrates and expand the functionality of the active site of the synthetase. We propose that orthogonal use of the same active site may be a general way to develop multifunctionality of human tRNA synthetases and other proteins.

  17. Immobilized low-activity waste site borehole 299-E17-21

    International Nuclear Information System (INIS)

    Reidel, S.P.; Reynolds, K.D.; Horton, D.G.

    1998-08-01

    The Tank Waste Remediation System (TWRS) is the group at the Hanford Site responsible for the safe underground storage of liquid waste from previous Hanford Site operations, the storage and disposal of immobilized tank waste, and closure of underground tanks. The current plan is to dispose of immobilized low-activity tank waste (ILAW) in new facilities in the southcentral part of 200-East Area and in four existing vaults along the east side of 200-East Area. Boreholes 299-E17-21, B8501, and B8502 were drilled at the southwest corner of the ILAW site in support of the Performance Assessment activities for the disposal options. This report summarizes the initial geologic findings, field tests conducted on those boreholes, and ongoing studies. One deep (480 feet) borehole and two shallow (50 feet) boreholes were drilled at the southwest corner of the ILAW site. The primary factor dictating the location of the boreholes was their characterization function with respect to developing the geohydrologic model for the site and satisfying associated Data Quality Objectives. The deep borehole was drilled to characterize subsurface conditions beneath the ILAW site, and two shallow boreholes were drilled to support an ongoing environmental tracer study. The tracer study will supply information to the Performance Assessment. All the boreholes provide data on the vadose zone and saturated zone in a previously uncharacterized area

  18. 3D Coupled Thermal-Hydraulic Model of the Lower Yarmouk Gorge, Jordan Rift Valley

    Science.gov (United States)

    Walther, M.; Magri, F.; Inbar, N.; Möller, P.; Raggad, M.; Rödiger, T.; Rosenthal, E.; Shentsis, I.; Siebert, C.; Volpi, G.

    2017-12-01

    It is supposed that the Lower Yarmouk Gorge (LYG), in the Jordan Rift Valley acts as the mixing zone of two crossing flow pathways: N-S from the Hermon Mountains and from the Ajlun Dome, and E-W from Jebel al Arab Mountain in Syria (also known as Huran Plateau or Yarmouk drainage basin). As a result, several springs can be found within the gorge. These are characterized by widespread temperatures (20 - 60 °C) which indicate that, beside the complex regional flow, also ascending thermal waters control the hydrologic behavior of the LYG. Previous simulations based on a conceptual simplified 3D model (Magri et al., 2016) showed that crossing flow paths result from the coexistence of convection, that can develop for example along NE-SW oriented faults within the gorge or in permeable aquifers below Maastrichtian aquiclude, and additional flow fields that are induced by the N-S topographic gradients. Here we present the first 3D hydrogeological model of the entire LYG that includes structural features based on actual logs and interpreted seismic lines from both Israeli and Jordanian territories. The model distinguishes seven units from upper Eocene to the Lower Triassic, accounting for major aquifers, aquicludes and deep-cutting faults. Recharges are implemented based on the numerical representation developed by Shentsis (1990) that considers relationships between mean annual rain and topographic elevation. The model reveals that topography-driven N-S and E-W flows strongly control the location of discharge areas while the anomalous spring temperature is not necessarily linked to the presence of fault convection. Local permeability anisotropy due to aquifers folding or facies changes are features sufficient for the rising of hot fluids. Shentsis, I., 1990. Mathematical models for long-term prediction of mountainous river runoff: methods, information and results, Hydrological Sciences Journal, 35:5, 487-500 Magri, F., Möller, S., Inbar, N., Möller, P., Raggad, M., R

  19. Simulation of land use change in the three gorges reservoir area based on CART-CA

    Science.gov (United States)

    Yuan, Min

    2018-05-01

    This study proposes a new method to simulate spatiotemporal complex multiple land uses by using classification and regression tree algorithm (CART) based CA model. In this model, we use classification and regression tree algorithm to calculate land class conversion probability, and combine neighborhood factor, random factor to extract cellular transformation rules. The overall Kappa coefficient is 0.8014 and the overall accuracy is 0.8821 in the land dynamic simulation results of the three gorges reservoir area from 2000 to 2010, and the simulation results are satisfactory.

  20. Directing reaction pathways by catalyst active-site selection using self-assembled monolayers.

    Science.gov (United States)

    Pang, Simon H; Schoenbaum, Carolyn A; Schwartz, Daniel K; Medlin, J Will

    2013-01-01

    One key route for controlling reaction selectivity in heterogeneous catalysis is to prepare catalysts that exhibit only specific types of sites required for desired product formation. Here we show that alkanethiolate self-assembled monolayers with varying surface densities can be used to tune selectivity to desired hydrogenation and hydrodeoxygenation products during the reaction of furfural on supported palladium catalysts. Vibrational spectroscopic studies demonstrate that the selectivity improvement is achieved by controlling the availability of specific sites for the hydrogenation of furfural on supported palladium catalysts through the selection of an appropriate alkanethiolate. Increasing self-assembled monolayer density by controlling the steric bulk of the organic tail ligand restricts adsorption on terrace sites and dramatically increases selectivity to desired products furfuryl alcohol and methylfuran. This technique of active-site selection simultaneously serves both to enhance selectivity and provide insight into the reaction mechanism.

  1. Active catalytic sites in the ammoxidation of propane and propene over V-Sb-O catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, S.A.; Zanthoff, H.W. [Bochum Univ. (Germany). Lehrstuhl fuer Technische Chemie

    1998-12-31

    The ammoxidation of propane over VSb{sub y}O{sub x} catalysts (y=1, 2, 5) was investigated with respect to the role of different oxygen species in the selective and non selective reaction steps using transient experiments in the Temporal Analysis of Products (TAP) reactor. Only lattice oxygen is involved in the oxidation reactions. Using isotopic labelled oxygen it is shown that two different active sites exist on the surface. On site A, which can be reoxidized faster by gas phase oxygen compared to site B, mainly CO is formed. On site B CO{sub 2} and acrolein as well as NO and N{sub 2}O in the presence of ammonia in the feed gas are formed and reoxidation mainly occurs with bulk lattice oxygen. (orig.)

  2. Recent Experience Using Active Love Wave Techniques to Characterize Seismographic Station Sites

    Science.gov (United States)

    Martin, A. J.; Yong, A.; Salomone, L.

    2014-12-01

    Active-source Love waves recorded by the multi-channel analysis of surface wave (MASLW) technique were recently analyzed in two site characterization projects. Between 2010 and 2011, the 2009 American Recovery and Reinvestment Act (ARRA) funded GEOVision to conduct geophysical investigations at 189 seismographic stations—185 in California and 4 in the Central Eastern U.S. (CEUS). The original project plan was to utilize active and passive Rayleigh wave-based techniques to obtain shear-wave velocity (VS) profiles to a minimum depth of 30 m and the time-averaged VS of the upper 30 meters (VS30). Early in the investigation it became evident that Rayleigh wave techniques, such as multi-channel analysis of surface waves (MASRW), were not effective at characterizing all sites. Shear-wave seismic refraction and MASLW techniques were therefore applied. The MASLW technique was deployed at a total of 38 sites, in addition to other methods, and used as the primary technique to characterize 22 sites, 5 of which were also characterized using Rayleigh wave techniques. In 2012, the Electric Power Research Institute funded characterization of 33 CEUS station sites. Based on experience from the ARRA investigation, both MASRW and MASLW data were acquired by GEOVision at 24 CEUS sites—the remaining 9 sites and 2 overlapping sites were characterized by University of Texas, Austin. Of the 24 sites characterized by GEOVision, 16 were characterized using MASLW data, 4 using both MASLW and MASRW data and 4 using MASRW data. Love wave techniques were often found to perform better, or at least yield phase velocity data that could be more readily modeled using the fundamental mode assumption, at shallow rock sites, sites with steep velocity gradients, and, sites with a thin, low velocity, surficial soil layer overlying stiffer sediments. These types of velocity structure often excite dominant higher modes in Rayleigh wave data, but not in Love wave data. At such sites, it may be possible

  3. Active site diversification of P450cam with indole generates catalysts for benzylic oxidation reactions

    Directory of Open Access Journals (Sweden)

    Paul P. Kelly

    2015-09-01

    Full Text Available Cytochrome P450 monooxygenases are useful biocatalysts for C–H activation, and there is a need to expand the range of these enzymes beyond what is naturally available. A panel of 93 variants of active self-sufficient P450cam[Tyr96Phe]-RhFRed fusion enzymes with a broad diversity in active site amino acids was developed by screening a large mutant library of 16,500 clones using a simple, highly sensitive colony-based colorimetric screen against indole. These mutants showed distinct fingerprints of activity not only when screened in oxidations of substituted indoles but also for unrelated oxidations such as benzylic hydroxylations.

  4. A three-dimensional model of mammalian tyrosinase active site accounting for loss of function mutations.

    Science.gov (United States)

    Schweikardt, Thorsten; Olivares, Concepción; Solano, Francisco; Jaenicke, Elmar; García-Borrón, José Carlos; Decker, Heinz

    2007-10-01

    Tyrosinases are the first and rate-limiting enzymes in the synthesis of melanin pigments responsible for colouring hair, skin and eyes. Mutation of tyrosinases often decreases melanin production resulting in albinism, but the effects are not always understood at the molecular level. Homology modelling of mouse tyrosinase based on recently published crystal structures of non-mammalian tyrosinases provides an active site model accounting for loss-of-function mutations. According to the model, the copper-binding histidines are located in a helix bundle comprising four densely packed helices. A loop containing residues M374, S375 and V377 connects the CuA and CuB centres, with the peptide oxygens of M374 and V377 serving as hydrogen acceptors for the NH-groups of the imidazole rings of the copper-binding His367 and His180. Therefore, this loop is essential for the stability of the active site architecture. A double substitution (374)MS(375) --> (374)GG(375) or a single M374G mutation lead to a local perturbation of the protein matrix at the active site affecting the orientation of the H367 side chain, that may be unable to bind CuB reliably, resulting in loss of activity. The model also accounts for loss of function in two naturally occurring albino mutations, S380P and V393F. The hydroxyl group in S380 contributes to the correct orientation of M374, and the substitution of V393 for a bulkier phenylalanine sterically impedes correct side chain packing at the active site. Therefore, our model explains the mechanistic necessity for conservation of not only active site histidines but also adjacent amino acids in tyrosinase.

  5. Mechanochemical coupling in the myosin motor domain. I. Insights from equilibrium active-site simulations.

    Directory of Open Access Journals (Sweden)

    Haibo Yu

    2007-02-01

    Full Text Available Although the major structural transitions in molecular motors are often argued to couple to the binding of Adenosine triphosphate (ATP, the recovery stroke in the conventional myosin has been shown to be dependent on the hydrolysis of ATP. To obtain a clearer mechanistic picture for such "mechanochemical coupling" in myosin, equilibrium active-site simulations with explicit solvent have been carried out to probe the behavior of the motor domain as functions of the nucleotide chemical state and conformation of the converter/relay helix. In conjunction with previous studies of ATP hydrolysis with different active-site conformations and normal mode analysis of structural flexibility, the results help establish an energetics-based framework for understanding the mechanochemical coupling. It is proposed that the activation of hydrolysis does not require the rotation of the lever arm per se, but the two processes are tightly coordinated because both strongly couple to the open/close transition of the active site. The underlying picture involves shifts in the dominant population of different structural motifs as a consequence of changes elsewhere in the motor domain. The contribution of this work and the accompanying paper [] is to propose the actual mechanism behind these "population shifts" and residues that play important roles in the process. It is suggested that structural flexibilities at both the small and large scales inherent to the motor domain make it possible to implement tight couplings between different structural motifs while maintaining small free-energy drops for processes that occur in the detached states, which is likely a feature shared among many molecular motors. The significantly different flexibility of the active site in different X-ray structures with variable level arm orientations supports the notation that external force sensed by the lever arm may transmit into the active site and influence the chemical steps (nucleotide

  6. Site-SpecificCu Labeling of the Serine Protease, Active Site Inhibited Factor Seven Azide (FVIIai-N), Using Copper Free Click Chemistry

    DEFF Research Database (Denmark)

    Jeppesen, Troels E; Kristensen, Lotte K; Nielsen, Carsten H

    2018-01-01

    A method for site-specific radiolabeling of the serine protease active site inhibited factor seven (FVIIai) with64Cu has been applied using a biorthogonal click reaction. FVIIai binds to tissue factor (TF), a trans-membrane protein involved in hemostasis, angiogenesis, proliferation, cell migrati...

  7. Identification and characterization of radioactively contaminated sites in Ukraine and planning for environmental restoration activities

    International Nuclear Information System (INIS)

    Soroka, Y.

    2000-01-01

    In the Pridniprovsk-Krivoy Rog region uranium, titanium, iron and manganese ores were mined and milled beginning in the 1950s. These activities have caused radioactive contamination of the environment at some sites. In recent times intensive works concerning the surveying of contaminated areas and substantiating the need for remediation have been initiated. The research methodologies applied and the results from radiation surveys are presented for the site of the first uranium mine in the Ukraine, for tailings originating from the Pridniprovsk Chemical Plant (PChP), for the recultivated dump-site of the former 'O'-mine, as well as for the wastes, raw materials and production of the Nicopol Ferro-Alloy Plant. The planning procedure for the remediation activities at the town of Zhovty Vody is described. (author)

  8. Remediation of uranium contaminated sites: clean-up activities in Serbia

    International Nuclear Information System (INIS)

    Raicevic, S.; Raicevic, J. . E-mail address of corresponding author: raich@beotel.yu; Raicevic, S.)

    2005-01-01

    One of the serious environmental problems in Serbia represent sites contaminated with depleted uranium (DU) during past war activities. According to UNEP reports and our findings there are two types of contamination: (i) localized points of high, concentrated contamination where DU penetrators enter the soil, and (ii) low level of widespread DU contamination, which indicates that during the conflict DU dust was dispersed into the environment. Remediation of these sites is an urgent need because they represent a permanent threat to the population living in this area. Here we give a brief description of approaches commonly used in remediation of DU contaminated sites, and an overview of current clean-up activities performed in Serbia. (author)

  9. Screening Approach to the Activation of Soil and Contamination of Groundwater at Linear Proton Accelerator Sites

    CERN Document Server

    Otto, Thomas

    The activation of soil and the contamination of groundwater at proton accelerator sites with the radionuclides 3H and 22Na are estimated with a Monte-Carlo calculation and a conservative soil- and ground water model. The obtained radionuclide concentrations show that the underground environment of future accelerators must be adequately protected against a migration of activation products. This study is of particular importance for the proton driver accelerator in the planned EURISOL facility.

  10. Examination of a Social-Networking Site Activities Scale (SNSAS) Using Rasch Analysis

    Science.gov (United States)

    Alhaythami, Hassan; Karpinski, Aryn; Kirschner, Paul; Bolden, Edward

    2017-01-01

    This study examined the psychometric properties of a social-networking site (SNS) activities scale (SNSAS) using Rasch Analysis. Items were also examined with Rasch Principal Components Analysis (PCA) and Differential Item Functioning (DIF) across groups of university students (i.e., males and females from the United States [US] and Europe; N =…

  11. Electrochemical probing into the active sites of graphitic-layer encapsulated iron oxygen reduction reaction electrocatalysts

    DEFF Research Database (Denmark)

    Zhong, Lijie; Jensen, Jens Oluf; Cleemann, Lars Nilausen

    2018-01-01

    is still unclear compared with the well-recognized surface coordinated FeNx/C structure. Using the strong complexing effect of the iron component with anions, cyanide (CN−) in alkaline and thiocyanate (SCN−) in acidic media, the metal containing active sites are electrochemically probed. Three...

  12. Heme-Protein Active Site Models via Self-Assembly in Water

    NARCIS (Netherlands)

    Fiammengo, R.; Wojciechowski, Kamil; Crego Calama, Mercedes; Figoli, A.; Wessling, Matthias; Reinhoudt, David; Timmerman, P.

    2003-01-01

    Water-soluble models of heme-protein active sites are obtained via the self-assembly of cationic porphyrins 1 and tetrasulfonato calix[4]arene 2 (K1·2 = 105 M-1). Selective binding of ligands either outside or inside the cavity of assemblies 1·2 via coordination to the zinc center has been observed.

  13. Aberration-corrected imaging of active sites on industrial catalyst nanoparticles

    DEFF Research Database (Denmark)

    Gontard, Lionel Cervera; Chang, L-Y; Hetherington, CJD

    2007-01-01

    Picture perfect: Information about the local topologies of active sites on commercial nanoparticles can be gained with atomic resolution through spherical-aberration-corrected transmission electron microscopy (TEM). A powder of Pt nanoparticles on carbon black was examined with two advanced TEM t...

  14. 113Cd NMR as a Probe of the Active Sites of Metalloenzymes

    NARCIS (Netherlands)

    Armitage, Ian M.; Schoot Uiterkamp, Antonius J.M.; Chlebowski, Jan F.; Coleman, Joseph E.

    1978-01-01

    113Cd NMR has been used to study the active site metal ion(s) of the 113Cd(II) derivatives of four Zn(II) metalloenzymes, carboxypeptidase A, carbonic anhydrases, alkaline phosphatase, and superoxide dismutase. The resonances of the enzyme-bound 113Cd(II) ions are extremely sensitive to ligand

  15. Application of QA grading to Yucca Mountain Site Characterization Project items and activities

    International Nuclear Information System (INIS)

    Murthy, R.B.; Smith, S.C.

    1991-01-01

    Grading is the act of selecting the quality assurance (QA) measures necessary to develop and maintain confidence in the quality of an item or activity. The list of QA measures from which this selection is made are the 20 criteria of the Yucca Mountain Site Characterization Project Quality Assurance Requirements Document

  16. Identification of the provenience of Majolica from sites in the Caribbean using neutron activation analysis

    International Nuclear Information System (INIS)

    Olin, J.S.; Sayre, E.V.

    1975-01-01

    Tin-enamelled earthenware pottery from five early Spanish Colonial sites in the Dominican Republic and Venezuela were sampled and analyzed by neutron activation analysis in an attempt to determine whether these sherds had a common source. The tentative conclusion was that although several sources were indicated for the specimens analyzed the overall similarity in composition indicated that these sources were probably closely related

  17. Active site electrostatics protect genome integrity by blocking abortive hydrolysis during DNA recombination

    Science.gov (United States)

    Ma, Chien-Hui; Rowley, Paul A; Macieszak, Anna; Guga, Piotr; Jayaram, Makkuni

    2009-01-01

    Water, acting as a rogue nucleophile, can disrupt transesterification steps of important phosphoryl transfer reactions in DNA and RNA. We have unveiled this risk, and identified safeguards instituted against it, during strand cleavage and joining by the tyrosine site-specific recombinase Flp. Strand joining is threatened by a latent Flp endonuclease activity (type I) towards the 3′-phosphotyrosyl intermediate resulting from strand cleavage. This risk is not alleviated by phosphate electrostatics; neutralizing the negative charge on the scissile phosphate through methylphosphonate (MeP) substitution does not stimulate type I endonuclease. Rather, protection derives from the architecture of the recombination synapse and conformational dynamics within it. Strand cleavage is protected against water by active site electrostatics. Replacement of the catalytic Arg-308 of Flp by alanine, along with MeP substitution, elicits a second Flp endonuclease activity (type II) that directly targets the scissile phosphodiester bond in DNA. MeP substitution, combined with appropriate active site mutations, will be useful in revealing anti-hydrolytic mechanisms engendered by systems that mediate DNA relaxation, DNA transposition, site-specific recombination, telomere resolution, RNA splicing and retrohoming of mobile introns. PMID:19440204

  18. Metal ion site engineering indicates a global toggle switch model for seven-transmembrane receptor activation

    DEFF Research Database (Denmark)

    Elling, Christian E; Frimurer, Thomas M; Gerlach, Lars-Ole

    2006-01-01

    for monoamine binding in TM-III, was used as the starting point to engineer activating metal ion sites between the extracellular segments of the beta2-adrenergic receptor. Cu(II) and Zn(II) alone and in complex with aromatic chelators acted as potent (EC50 decreased to 0.5 microm) and efficacious agonists...

  19. Substrate binding in the active site of cytochrome P450cam

    NARCIS (Netherlands)

    Swart, M.; Groenhof, A.R.; Ehlers, A.W.; Lammertsma, K.

    2005-01-01

    We have studied the binding of camphor in the active site of cytochrome P450cam with density functional theory (DFT) calculations. A strong hydrogen bond (>6 kcal/mol) to a tyrosine residue (Tyr96) is observed, that may account for the high specificity of the reaction taking place. The DFT

  20. Influenza B viruses with mutation in the neuraminidase active site, North Carolina, USA, 2010-11.

    Science.gov (United States)

    Sleeman, Katrina; Sheu, Tiffany G; Moore, Zack; Kilpatrick, Susan; Garg, Shikha; Fry, Alicia M; Gubareva, Larisa V

    2011-11-01

    Oseltamivir is 1 of 2 antiviral medications available for the treatment of influenza B virus infections. We describe and characterize a cluster of influenza B viruses circulating in North Carolina with a mutation in the neuraminidase active site that may reduce susceptibility to oseltamivir and the investigational drug peramivir but not to zanamivir.

  1. United States and European students’ social-networking site activities and academic performance

    NARCIS (Netherlands)

    Karpinski, Aryn; Kirschner, Paul A.; Shreffler, Anthony; Albert, Patricia; Tomko, Carrie

    2018-01-01

    Different cultures communicate differently. Research is beginning to examine the differences in culture related to social-networking site (SNS) use. Differences in specific SNS activities related to academic performance among United States (US; n = 446) and European (n = 394) university students

  2. Gasification under CO2–Steam Mixture: Kinetic Model Study Based on Shared Active Sites

    Directory of Open Access Journals (Sweden)

    Xia Liu

    2017-11-01

    Full Text Available In this work, char gasification of two coals (i.e., Shenfu bituminous coal and Zunyi anthracite and a petroleum coke under a steam and CO2 mixture (steam/CO2 partial pressures, 0.025–0.075 MPa; total pressures, 0.100 MPa and CO2/steam chemisorption of char samples were conducted in a Thermogravimetric Analyzer (TGA. Two conventional kinetic models exhibited difficulties in exactly fitting the experimental data of char–steam–CO2 gasification. Hence, a modified model based on Langmuir–Hinshelwood model and assuming that char–CO2 and char–steam reactions partially shared active sites was proposed and had indicated high accuracy for estimating the interactions in char–steam–CO2 reaction. Moreover, it was found that two new model parameters (respectively characterized as the amount ratio of shared active sites to total active sites in char–CO2 and char–steam reactions in the modified model hardly varied with gasification conditions, and the results of chemisorption indicate that these two new model parameters mainly depended on the carbon active sites in char samples.

  3. Impact of the Three Gorges project on ecological environment changes and snail distribution in Dongting Lake area.

    Directory of Open Access Journals (Sweden)

    Feiyue Li

    2017-07-01

    Full Text Available The Three Gorges Dam (TGD is a remarkable, far-reaching project in China. This study was conducted to assess the impact of TGD on changes in the ecological environment, snail distribution and schistosomiasis transmission in Dongting Lake area.Hydrological data were collected from 12 monitoring sites in Hunan section of Yangtze River before and after TGD was established. Data on snail distribution and human schistosomiasis infection were also collected. Correlation analyses were performed to detect the significance of snail distribution to changes in ecological environmental factors and human schistosomiasis infection.A series of ecological environmental factors have changed in Dongting Lake area following the operation of TGD. Volume of annual runoff discharged into Dongting Lake declined by 20.85%. Annual sediment volume discharged into the lake and the mean lake sedimentation rate decreased by 73.9% and 32.2%, respectively. From 2003 to 2015, occurrence rate of frames with living snails and mean density of living snails decreased overall by 82.43% and 94.35%, respectively, with annual decrements being 13.49% and 21.29%. Moreover, human infection rate of schistosomiasis had decreased from 3.38% in 2003 to 0.44% in 2015, with a reduction of 86.98%. Correlation analyses showed that mean density of living snails was significantly associated with water level (r = 0.588, p<0.001, as well as the mean elevation range of the bottomland (r = 0.374, p = 0.025 and infection rate of schistosomiasis (r = 0.865, p<0.001.Ecological environmental changes caused by the TGD were associated with distribution of snails, and might further affect the transmission and prevalence of schistosomiasis. Risk of schistosomiasis transmission still exists in Dongting Lake area and long-term monitoring is required.

  4. Sedimentation in the Three Gorges Dam and the future trend of Changjiang (Yangtze River sediment flux to the sea

    Directory of Open Access Journals (Sweden)

    Guogang Li

    2009-11-01

    Full Text Available The Three Gorges Dam (TGD on the upper Changjiang (Yangtze River, China, disrupts the continuity of Changjiang sediment delivery to downstream and coastal areas. In this study, which was based on 54 years of annual water and sediment data from the mainstream and major tributaries of Changjiang, sediment deposition induced by the TGD in 2003–2008 was quantified. Furthermore, we determined the theoretical trapping efficiency of the cascade reservoir upstream of the TGD. Its impact on Changjiang sediment flux in the coming decades is discussed. Results show that about 172 million tons (Mt of sediment was trapped annually by the TGD in 2003–2008, with an averaged trapping efficiency of 75%. Most of the total sediment deposition, as induced by the TGD (88%, accumulated within the region between the TGD site and Cuntan. However, significant siltation (12% of the total sediment deposition also occurred upstream of Cuntan as a consequence of the upstream extended backwater region of the TGD. Additionally, the Changjiang sediment flux entered a third downward step in 2001, prior to operation of the TGD. This mainly resulted from sediment reduction in the Jinshajiang tributary since the late 1990s. As the cascade reservoir is put into full operation, it could potentially trap 91% of the Jinshajiang sediment discharge and, therefore, the Jinshajiang sediment discharge would most likely further decrease to 14 Mt/yr in the coming decades. Consequently, the Changjiang sediment flux to the sea is expected to continuously decrease to below 90 Mt/yr in the near future, or only 18% of the amount observed in the 1950s. In the presence of low sediment discharge, profound impacts on the morphology of estuary, delta and coastal waters are expected.

  5. Nest predation increases with parental activity: separating nest site and parental activity effects.

    OpenAIRE

    Martin, T E; Scott, J; Menge, C

    2000-01-01

    Alexander Skutch hypothesized that increased parental activity can increase the risk of nest predation. We tested this hypothesis using ten open-nesting bird species in Arizona, USA. Parental activity was greater during the nestling than incubation stage because parents visited the nest frequently to feed their young during the nestling stage. However, nest predation did not generally increase with parental activity between nesting stages across the ten study species. Previous investigators h...

  6. Requirement of histidine 217 for ubiquinone reductase activity (Qi site) in the cytochrome bc1 complex.

    Science.gov (United States)

    Gray, K A; Dutton, P L; Daldal, F

    1994-01-25

    Folding models suggest that the highly conserved histidine 217 of the cytochrome b subunit from the cytochrome bc1 complex is close to the quinone reductase (Qi) site. This histidine (bH217) in the cytochrome b polypeptide of the photosynthetic bacterium Rhodobacter capsulatus has been replaced with three other residues, aspartate (D), arginine (R), and leucine (L). bH217D and bH217R are able to grow photoheterotrophically and contain active cytochrome bc1 complexes (60% of wild-type activity), whereas the bH217L mutant is photosynthetically incompetent and contains a cytochrome bc1 complex that has only 10% of the wild-type activity. Single-turnover flash-activated electron transfer experiments show that cytochrome bH is reduced via the Qo site with near native rates in the mutant strains but that electron transfer between cytochrome bH and quinone bound at the Qi site is greatly slowed. These results are consistent with redox midpoint potential (Em) measurements of the cytochrome b subunit hemes and the Qi site quinone. The Em values of cyt bL and bH are approximately the same in the mutants and wild type, although the mutant strains have a larger relative concentration of what may be the high-potential form of cytochrome bH, called cytochrome b150. However, the redox properties of the semiquinone at the Qi site are altered significantly. The Qi site semiquinone stability constant of bH217R is 10 times higher than in the wild type, while in the other two strains (bH217D and bH217L) the stability constant is much lower than in the wild type. Thus H217 appears to have major effects on the redox properties of the quinone bound at the Qi site. These data are incorporated into a suggestion that H217 forms part of the binding pocket of the Qi site in a manner reminiscent of the interaction between quinone bound at the Qb site and H190 of the L subunit of the bacterial photosynthetic reaction center.

  7. Active Holiday in Mt. Zlatibor County

    Directory of Open Access Journals (Sweden)

    Jovan Plavša

    2009-01-01

    Full Text Available Active holiday presents a new stream in tourism development of Serbia. The most interesting types of active holiday in Serbia are: free and mountain biking, rafting, hiking, mountaineering, free climbing, orienteering, fishing, sailing, rowing, paragliding, cave exploring, skiing, survival in nature, zorbing, horse riding, etc. Zlatibor district is almost perfect area for developing active holiday, due to the nature beauties and diversity of landscape. The most atractive parts for developing active holiday in Zlatibor district are: Tara Mountain and Drina River Gorge, Zlatibor Mountain, Uvac River Gorge and Zlatar Mountain, Lim River Valley and Pester Highlands.

  8. In situ ∼2.0 Ma trees discovered as fossil rooted stumps, lowermost Bed I, Olduvai Gorge, Tanzania.

    Science.gov (United States)

    Habermann, Jörg M; Stanistreet, Ian G; Stollhofen, Harald; Albert, Rosa M; Bamford, Marion K; Pante, Michael C; Njau, Jackson K; Masao, Fidelis T

    2016-01-01

    The discovery of fossil rooted tree stumps in lowermost Lower Bed I from the western Olduvai Basin, Tanzania, age-bracketed by the Naabi Ignimbrite (2.038 ± 0.005 Ma) and Tuff IA (1.88 ± 0.05 Ma), provides the first direct, in situ, and to date oldest evidence of living trees at Olduvai Gorge. The tree relicts occur in an interval dominated by low-viscosity mass flow and braided fluvial sediments, deposited at the toe of a largely Ngorongoro Volcano-sourced volcaniclastic fan apron that comprised a widely spaced network of ephemeral braided streams draining northward into the Olduvai Basin. Preservation of the trees occurred through their engulfment by mass flows, post-mortem mold formation resulting from differential decay of woody tissues, and subsequent fluvially-related sediment infill, calcite precipitation, and cast formation. Rhizolith preservation was triggered by the interaction of root-induced organic and inorganic processes to form rhizocretionary calcareous root casts. Phytolith analyses were carried out to complete the paleoenvironmental reconstruction. They imply a pronounced seasonality and indicate a wooded landscape with grasses, shrubs, and sedges growing nearby, comparable to the low, open riverine woodland (unit 4c) along the Garusi River and tributaries in the Laetoli area. Among the tree stump cluster were found outsized lithic clasts and those consisting of quartzite were identified as Oldowan stone tool artifacts. In the context of hominin activity, the identification of wooded grassland in association with nearby freshwater drainages and Oldowan artifacts significantly extends our paleoenvironmental purview on the basal parts of Lower Bed I, and highlights the hitherto underrated role of the yet poorly explored western Olduvai Gorge area as a potential ecologically attractive setting and habitat for early hominins. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Wide-Area Landslide Deformation Mapping with Multi-Path ALOS PALSAR Data Stacks: A Case Study of Three Gorges Area, China

    Directory of Open Access Journals (Sweden)

    Xuguo Shi

    2016-02-01

    Full Text Available In recent years, satellite synthetic aperture radar interferometry (InSAR has been adopted as a spaceborne geodetic tool to successfully measure surface deformation of a few well-known landslides in the Three Gorges area. In consideration of the fact that most events of slope failure happened at places other than those famous landslides since the reservoir impoundment in 2003, focusing on a limited number of slopes is insufficient to meet the requirements of regional-scale landslide disaster prevention and early warning. As a result, it has become a vital task to evaluate the overall stability of slopes across the vast area of Three Gorges using wide-coverage InSAR datasets. In this study, we explored the approach of carrying out joint analysis of multi-path InSAR data stacks for wide-area landslide deformation mapping. As an example, three ALOS (Advanced Land Observing Satellite PALSAR (Phased Array type L-band Synthetic Aperture Radar data stacks of neighboring ascending paths covering the area along the Yangtze River from Fengjie to Zigui were analyzed. A key problem to be solved is the separation of the tropospheric signal from the interferometric phase, for which we employed a hybrid description model of the atmospheric phase screen (APS to improve APS estimation from time series interferograms. The estimated atmospheric phase was largely correlated with the seasonal rainfall in the temporal dimension. The experimental results show that about 30 slopes covering total areas of 48 km2 were identified to be landslides in active deformation and should be kept under routine surveillance. Analyses of time series displacement measurements revealed that most landslides in the mountainous area far away from Yangtze River suffered from linear deformation, whereas landslides located on the river bank were destabilized predominantly by the influences of reservoir water level fluctuation and rainfall.

  10. Characterization and sequencing of the active site of 1-aminocyclopropane-1-carboxylate synthase

    International Nuclear Information System (INIS)

    Yip, Wing-Kin; Dong, Jian-Guo; Yang, S.F.; Kenny, J.W.; Thompson, G.A.

    1990-01-01

    The pyridoxal phosphate (PLP)-dependent 1-aminocyclopropane-1-carboxylic acid (ACC) synthase the key enzyme in ethylene biosynthesis, is inactivated by its substrate S-adenosylmethionine (AdoMet). Apple ACC synthase was purified with an immunoaffinity gel, and its active site was probed with NaB 3 H 4 or Ado[ 14 C]Met. Peptide sequencing of both 3 H- and 14 C-labeled peptides revealed a common dodecapeptide of Ser-Leu-Ser-Xaa-Asp-Leu-Gly-Leu-Pro-Gly-Phe-Arg, where Xaa was the modified, radioactive residue in each case. Acid hydrolysis of the 3 H-labeled enzyme released radioactive N-pyridoxyllysine, indicating that the active-site peptide contained lysine at position 4. Mass spectrometry of the 14 C-labeled peptide indicated a protonated molecular ion at m/z 1390.6, from which the mass of Xaa was calculated to be 229, a number that is equivalent to the mass of a lysine residue alkylated by the 2-aminobutyrate portion of AdoMet, as we previously proposed. These results indicate that the same active-site lysine binds the PLP and convalently links to the 2-aminobutyrate portion of AdoMet during inactivation. The active site of tomato ACC synthase was probed in the same manner with Ado [ 14 C]Met. Sequencing of the tomato active-site peptide revealed two highly conserved dodecapeptides; the minor peptide possessed a sequence identical to that of the apple enzyme, whereas the major peptide differed from the minor peptide in that methionine replaced leucine at position 6

  11. Management of Ground and Groundwater Contamination on a Compact Site Constrained by Ongoing Activities

    International Nuclear Information System (INIS)

    Eilbeck, K.E.; Reeve, P.

    2009-01-01

    Sellafield Site is a compact and complex site which since the 1940's has been home to a range of facilities associated with the production and reprocessing of fissile material. The site contains the UK equivalent of the Chicago Pile-1 reactor, Hanford B Reactor, Rocky Flats Buildings 771 and 774, West Valley Main Process Plant Building, Savannah River Vitrification Plant, Savannah River MOX Plant, Savannah River F Canyon, Hanford 222 Analytical Laboratory, Savannah River K-, L-, and P-Basins, and the Fort St. Vrain Reactor all in an area of approximately 1000 acres. Spent fuel reprocessing is still undertaken on site; however waste management and decommissioning activities are of increasing importance. These include the emptying and removal of fragile ponds and silos containing significant radioactive inventories, the decommissioning of reactors (including the world's first commercial reactor for power generation and the Windscale Piles, the site of a reactor fire in the late 1950's) and the construction of a new generation of vitrification and encapsulation plants. Leaks, spills and on-site disposals during the site's industrial lifetime have resulted in a legacy of fission products and other radionuclides in the ground and groundwater. Volumes of contaminated ground have been estimated as being as much as 18 million m 3 and an estimated below ground inventory of approximately 1.8 E16 Bq. These have all occurred within close proximity to a range of receptors including farm land and the sea. The cramped nature of the facilities on site, overlapping source terms and ongoing decommissioning, waste management and operating activities all raise significant challenges in the management and remediation of contaminated land and groundwater. The strategy to address these challenges includes: 1. Data collection, management and interpretation. The congested nature of the site and the age of some of the monitoring facilities has resulted in particular difficulties. For

  12. Number of active transcription factor binding sites is essential for the Hes7 oscillator

    Directory of Open Access Journals (Sweden)

    de Angelis Martin

    2006-02-01

    Full Text Available Abstract Background It is commonly accepted that embryonic segmentation of vertebrates is regulated by a segmentation clock, which is induced by the cycling genes Hes1 and Hes7. Their products form dimers that bind to the regulatory regions and thereby repress the transcription of their own encoding genes. An increase of the half-life of Hes7 protein causes irregular somite formation. This was shown in recent experiments by Hirata et al. In the same work, numerical simulations from a delay differential equations model, originally invented by Lewis, gave additional support. For a longer half-life of the Hes7 protein, these simulations exhibited strongly damped oscillations with, after few periods, severely attenuated the amplitudes. In these simulations, the Hill coefficient, a crucial model parameter, was set to 2 indicating that Hes7 has only one binding site in its promoter. On the other hand, Bessho et al. established three regulatory elements in the promoter region. Results We show that – with the same half life – the delay system is highly sensitive to changes in the Hill coefficient. A small increase changes the qualitative behaviour of the solutions drastically. There is sustained oscillation and hence the model can no longer explain the disruption of the segmentation clock. On the other hand, the Hill coefficient is correlated with the number of active binding sites, and with the way in which dimers bind to them. In this paper, we adopt response functions in order to estimate Hill coefficients for a variable number of active binding sites. It turns out that three active transcription factor binding sites increase the Hill coefficient by at least 20% as compared to one single active site. Conclusion Our findings lead to the following crucial dichotomy: either Hirata's model is correct for the Hes7 oscillator, in which case at most two binding sites are active in its promoter region; or at least three binding sites are active, in which

  13. Bacterial Abundance and Activity across Sites within Two Northern Wisconsin Sphagnum Bogs.

    Science.gov (United States)

    Fisher; Graham; Graham

    1998-11-01

    Abstract Bacterial abundance, temperature, pH, and dissolved organic carbon (DOC) concentration were compared across surface sites within and between two northern Wisconsin Sphagnum peatlands over the summer seasons in 1995 and 1996. Sites of interest were the Sphagnum mat surface, the water-filled moat (lagg) at the bog margin, and the bog lake littoral zone. Significant differences in both bacterial populations and water chemistry were observed between sites. pH was highest in the lake and lowest in the mat at both bogs; the opposite was true for DOC. Large populations of bacteria were present in surface interstitial water from the mat; abundance in this site was consistently higher than in the moat or lake. Bacterial abundance also increased across sites of increasing DOC concentration and declining pH. Bacterial activities (rates of [3H]leucine incorporation) and growth in dilution cultures (with grazers removed) were also assessed in lake, moat, and mat sites. Results using these measures generally supported the trends observed in abundance, although high rates of [3H]leucine incorporation were recorded in the moat at one of the bogs. Our results indicate that bacterial populations in Sphagnum peatlands are not adversely affected by acidity, and that DOC may be more important than pH in determining bacterial abundance in these environments.

  14. Roles of s3 site residues of nattokinase on its activity and substrate specificity.

    Science.gov (United States)

    Wu, Shuming; Feng, Chi; Zhong, Jin; Huan, Liandong

    2007-09-01

    Nattokinase (Subtilisin NAT, NK) is a bacterial serine protease with high fibrinolytic activity. To probe their roles on protease activity and substrate specificity, three residues of S3 site (Gly(100), Ser(101) and Leu(126)) were mutated by site-directed mutagenesis. Kinetics parameters of 20 mutants were measured using tetrapeptides as substrates, and their fibrinolytic activities were determined by fibrin plate method. Results of mutation analysis showed that Gly(100) and Ser(101) had reverse steric and electrostatic effects. Residues with bulky or positively charged side chains at position 100 decreased the substrate binding and catalytic activity drastically, while residues with the same characters at position 101 could obviously enhance protease and fibrinolytic activity of NK. Mutation of Leu(126) might impair the structure of the active cleft and drastically decreased the activity of NK. Kinetics studies of the mutants showed that S3 residues were crucial to keep protease activity while they moderately affected substrate specificity of NK. The present study provided some original insight into the P3-S3 interaction in NK and other subtilisins, as well as showed successful protein engineering cases to improve NK as a potential therapeutic agent.

  15. Integral Public Activities as a Support to the Site Selection Process for LILW Repository

    International Nuclear Information System (INIS)

    Zeleznik, N.; Kralj, M.

    2008-01-01

    The first site selection process for low and intermediate level radioactive waste (LILW) repository took place between 1990 and 1993 in Slovenia was stopped unsuccessfully with very strong public opposition at local level, followed by political withdrawal on national level. As one of the consequences ARAO started to develop new approach to the site selection based also on the findings from sociology, psychology and other human sciences. The recommendations on public involvement and transparency were so strong that ARAO started with first limited public relation (PR) activities which later grew to the PR process which supports all technical activities in ARAO. Presently the PR process covers communication, information and research activities and assures careful planning, prompt responds and involvement of the highest responsible persons at ARAO. Integral public relation activities are divided in several parts. Majority of activities support the on-going site selection process where activities are presently focused on functioning of local partnerships developed as a basic communication tool to involve as much citizens and public as possible on local level. Presently two local partnerships are working in Krsko and Brezice community with clear role to enhance public involvement according to Aarchus convention. Each of the partnerships is organized in a specific way adjusted to the local needs. Communication activities are organized also for different other projects and are preparing the necessary basis for the work with different groups of stake holders and in different situations. As a foundation very broad information material, such as books, leaflets, reports, magazines, video cassettes, CD and DVD on the radioactive waste management is prepared and used for different purposes. We also try to be proactive with web pages and have a well organized visitors' center. Improvement of public relation process is achieved through constant survey and feed-back information

  16. Expansion of access tunnels and active-site cavities influence activity of haloalkane dehalogenases in organic cosolvents.

    Science.gov (United States)

    Stepankova, Veronika; Khabiri, Morteza; Brezovsky, Jan; Pavelka, Antonin; Sykora, Jan; Amaro, Mariana; Minofar, Babak; Prokop, Zbynek; Hof, Martin; Ettrich, Rudiger; Chaloupkova, Radka; Damborsky, Jiri

    2013-05-10

    The use of enzymes for biocatalysis can be significantly enhanced by using organic cosolvents in the reaction mixtures. Selection of the cosolvent type and concentration range for an enzymatic reaction is challenging and requires extensive empirical testing. An understanding of protein-solvent interaction could provide a theoretical framework for rationalising the selection process. Here, the behaviour of three model enzymes (haloalkane dehalogenases) was investigated in the presence of three representative organic cosolvents (acetone, formamide, and isopropanol). Steady-state kinetics assays, molecular dynamics simulations, and time-resolved fluorescence spectroscopy were used to elucidate the molecular mechanisms of enzyme-solvent interactions. Cosolvent molecules entered the enzymes' access tunnels and active sites, enlarged their volumes with no change in overall protein structure, but surprisingly did not act as competitive inhibitors. At low concentrations, the cosolvents either enhanced catalysis by lowering K(0.5) and increasing k(cat), or caused enzyme inactivation by promoting substrate inhibition and decreasing k(cat). The induced activation and inhibition of the enzymes correlated with expansion of the active-site pockets and their occupancy by cosolvent molecules. The study demonstrates that quantitative analysis of the proportions of the access tunnels and active-sites occupied by organic solvent molecules provides the valuable information for rational selection of appropriate protein-solvent pair and effective cosolvent concentration. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Chinese engineers and scientists urge leadership to change Three Gorges Dam operating plan

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-04-26

    An appeal to the Chinese Leadership by a group of senior engineers, water management experts and academics about the dire consequences of filling the Three Gorges reservoir on the Yangtze River to 175 metres, is reported. Originally, the plan was to keep water levels behind the Three Gorges Dam at 156 metres for the first ten years of operation, in order to allow for resettlement of people displaced by building the dam, and to evaluate the impact of silt deposits on navigation and ports at the upper end of the reservoir. Plans have changed in 1997; the water level is now scheduled to rise to 175 metres in the sixth year of the dam's operation in order to maximize the dam's power output. The appeal by 53 experts warned the Chinese Government that the filling of the reservoir to 175 metres would displace 1.13 million people and raise the water level in the Yangtze River more than 10 metres at Chongqing City, submerging drainage outlets and backing up the city's sewage, as well as increase silt deposits, blocking shipping traffic along the Yangtze River. A parallel is drawn with the Sanmenxia Dam on the Yellow River. It was completed in 1960; it has proven to be useless for controlling floods while producing only one-third of its expected output due to massive silt build-up in the reservoir.

  18. Geographical Overview of the Three Gorges Dam and Reservoir, China - Geologic Hazards and Environmental Impacts

    Science.gov (United States)

    Highland, Lynn M.

    2008-01-01

    The Three Gorges Dam and Reservoir on the Yangtze River, China, has been an ambitious and controversial project. The dam, the largest in the world as of 2008, will provide hydropower, help to manage flood conditions, and increase the navigability of the Yangtze River. However, this massive project has displaced human and animal populations and altered the stability of the banks of the Yangtze, and it may intensify the seismic hazard of the area. It has also hindered archeological investigations in the reservoir and dam area. This report, originally in the form of a Microsoft PowerPoint presentation, gives a short history and overview of the dam construction and subsequent consequences, especially geologic hazards already noted or possible in the future. The report provides photographs, diagrams, and references for the reader's further research - a necessity, because this great undertaking is dynamic, and both its problems and successes continue to evolve. The challenges and consequences of Three Gorges Dam will be closely watched and documented as lessons learned and applied to future projects in China and elsewhere.

  19. Channel evolution under changing hydrological regimes in anabranching reaches downstream of the Three Gorges Dam

    Science.gov (United States)

    Han, Jianqiao; Zhang, Wei; Yuan, Jing; Fan, Yongyang

    2018-03-01

    Elucidating the influence of dams on fluvial processes can benefit river protection and basin management. Based on hydrological and topographical data, we analyzed channel evolution in anabranching reaches under changing hydrological regimes influenced by the Three Gorges Dam. The main conclusions are as follows: 1) the channels of specific anabranching reaches were defined as flood trend channels or low-flow trend channels according to the distribution of their flow characteristics. The anabranching reaches were classified as T1 or T2. The former is characterized by the correspondence between the flood trend and branch channels, and the latter is characterized by the correspondence between the flood trend and main channels; 2) on the basis of the new classification, the discrepant patterns of channel evolution seen in anabranching reaches were unified into a pattern that showed flood trend channels shrinking and low-flow trend channels expanding; 3) flood abatement and the increased duration of moderate flow discharges are the main factors that affect channel adjustments in anabranching reaches after dam construction; and 4) in the next few decades, the pattern of channel evolution will remain the same as that of the Three Gorges Dam operation. That is, the morphology will fully adapt to a flow with a low coefficient of variation. Our results are of interest in the management of the Yangtze River and other rivers influenced by dams.

  20. The dynamic capacity calculation method and the flood control ability of the Three Gorges Reservoir

    Science.gov (United States)

    Zhang, Shanghong; Jing, Zhu; Yi, Yujun; Wu, Yu; Zhao, Yong

    2017-12-01

    To evaluate the flood control ability of a river-type reservoir, an accurate simulation method for the flood storage, discharge process, and dynamic capacity of the reservoir is important. As the world's largest reservoir, the storage capacity and flood control capacity of the Three Gorges Reservoir (TGR) has attracted widespread interest and academic debate for nearly 20 years. In this study, a model for calculating the dynamic capacity of a river-type reservoir is established based on data from 394 river cross sections and 2.5-m resolution digital elevation model (DEM) data of the TGR area. The storage capacity and flood control capacity of the TGR were analysed based on the scheduling procedures of a normal impoundment period. The results show that the static capacity of the TGR is 43.43 billion m3, the dynamic flood control capacity is 22.45 billion m3, and the maximum floodwater flow regulated by the dynamic capacity at Zhicheng is no more than 67,700 m3/s. This study supply new simulation method and up-to-date high-precision data to discuss the 20 years debate, and the results reveal the TGR design is conservative for flood control according to the Preliminary Design Report of the Three Gorges Project. The dynamic capacity calculation method used here can provide a reference for flood regulation of large river-type reservoirs.

  1. Chinese engineers and scientists urge leadership to change Three Gorges Dam operating plan

    International Nuclear Information System (INIS)

    2000-01-01

    An appeal to the Chinese Leadership by a group of senior engineers, water management experts and academics about the dire consequences of filling the Three Gorges reservoir on the Yangtze River to 175 metres, is reported. Originally, the plan was to keep water levels behind the Three Gorges Dam at 156 metres for the first ten years of operation, in order to allow for resettlement of people displaced by building the dam, and to evaluate the impact of silt deposits on navigation and ports at the upper end of the reservoir. Plans have changed in 1997; the water level is now scheduled to rise to 175 metres in the sixth year of the dam's operation in order to maximize the dam's power output. The appeal by 53 experts warned the Chinese Government that the filling of the reservoir to 175 metres would displace 1.13 million people and raise the water level in the Yangtze River more than 10 metres at Chongqing City, submerging drainage outlets and backing up the city's sewage, as well as increase silt deposits, blocking shipping traffic along the Yangtze River. A parallel is drawn with the Sanmenxia Dam on the Yellow River. It was completed in 1960; it has proven to be useless for controlling floods while producing only one-third of its expected output due to massive silt build-up in the reservoir

  2. Assessing impacts on biological resources from Site Characterization Activities of the Yucca Mountain Project

    International Nuclear Information System (INIS)

    Green, R.A.; Cox, M.K.; Doerr, T.B.; O'Farrell, T.P.; Ostler, W.K.; Rautenstrauch, K.R.; Wills, C.A.

    1991-01-01

    An integrated impact assessment program was developed to monitor the possible effects of Site Characterization Activities (SCA) on the biological resources of the Yucca Mountain area. The program uses control and treatment sites incorporating both spatial and temporal controls. The selection of biotic variables for monitoring was based on their relative importance in the ecosystem and their ability to provide information on potential impacts. All measures of biotic and abiotic variables will be made on the same sample plots to permit linking changes in variables to each other

  3. Technical basis for classification of low-activity waste fraction from Hanford site tanks

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, C.A., Westinghouse Hanford

    1996-07-17

    The overall objective of this report is to provide a technical basis to support a U.S. Nuclear Regulatory Commission determination to classify the low-activity waste from the Hanford Site single-shell and double-shell tanks as `incidental` wastes after removal of additional radionuclides and immobilization.The proposed processing method, in addition to the previous radionuclide removal efforts, will remove the largest practical amount of total site radioactivity, attributable to high-level wastes, for disposal in a deep geologic repository. The remainder of the waste would be considered `incidental` waste and could be disposed onsite.

  4. Technical basis for classification of low-activity waste fraction from Hanford site tanks

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, C.A.

    1996-09-20

    The overall objective of this report is to provide a technical basis to support a U.S. Nuclear Regulatory Commission determination to classify the low-activity waste from the Hanford Site single-shell and double-shell tanks as `incidental` wastes after removal of additional radionuclides and immobilization.The proposed processing method, in addition to the previous radionuclide removal efforts, will remove the largest practical amount of total site radioactivity, attributable to high-level waste, for disposal is a deep geologic repository. The remainder of the waste would be considered `incidental` waste and could be disposed onsite.

  5. Regulatory inspection activities on nuclear power plant sites during construction in the United Kingdom

    International Nuclear Information System (INIS)

    Jeffery, J.V.

    1977-01-01

    The work of regulatory inspection of the construction of the plant on the site is performed not only by the inspector who has been allocated to inspection duties for that site but also by the specialist staff who are involved with the safety assessment of the plant. The co-ordination of this work is described in the paper and examples are given of inspection activities associated with the enforcement requirements of licence conditions as well as those related to the inspection of the plant itself. (author)

  6. Unraveling the Nature of Sites Active toward Hydrogen Peroxide Reduction in Fe?N?C Catalysts

    OpenAIRE

    Choi, Chang Hyuck; Choi, Won Seok; Kasian, Olga; Mechler, Anna K.; Sougrati, Moulay Tahar; Br?ller, Sebastian; Strickland, Kara; Jia, Qingying; Mukerjee, Sanjeev; Mayrhofer, Karl J. J.; Jaouen, Fr?d?ric

    2017-01-01

    Abstract Fe?N?C catalysts with high O2 reduction performance are crucial for displacing Pt in low?temperature fuel cells. However, insufficient understanding of which reaction steps are catalyzed by what sites limits their progress. The nature of sites were investigated that are active toward H2O2 reduction, a key intermediate during indirect O2 reduction and a source of deactivation in fuel cells. Catalysts comprising different relative contents of FeN x C y moieties and Fe particles encapsu...

  7. Assessment of national systems for obtaining local acceptance of nuclear waste management siting activities

    International Nuclear Information System (INIS)

    Paige, H.W.; Owens, J.E.

    1984-01-01

    On behalf of the United States Department of Energy (DOE), International Energy Associates Limited (IEAL) of Washington, D.C. has conducted surveys and analyses of fourteen countries' plans and approaches for dealing with the problems of obtaining local siting acceptance for nuclear waste management facilities. It was determined that the following elements of the formal systems generally facilitate and/or expedite waste management siting decisions: (1) a clear-cut pro-nuclear power position on the part of the government; (2) a willingness on the part of the central government to exert (with prudence and restraint) its pre-emptive rights in nuclear matters; (3) political structures in which the heads of regional or provincial governments are appointed by the central government; (4) national laws that link reactor licensing with a detailed plan for waste management; (5) an established and stable policy with regard to reprocessing. In contrast, it was determined that the following elements of the formal system generally hinder waste management siting activities: (1) historically strong local land used veto laws; (2) the use of national referenda for making nuclear decisions; (3) requirements for public hearings. The informal approaches fall into the following five categories: (1) political: e.g. assertion of will by political leaders, activities to enlist support of local politicians, activities to broaden involvement in decision-making; (2) economic: e.g. emphasis on normal benefits, provision for additional economic benefits; (3) siting: e.g. at or near existing nuclear facilities, on government or utility property, at multiple locations to spread the political burden; (4) timing: e.g. decoupling drilling activities from ultimate repository site decision, deliberate deferral to (long-range) future; (5) education: e.g. creation of special government programmes, enlisting of media support

  8. 3D hydrogeological model of the Lower Yarmouk Gorge, Jordan Rift Valley

    Science.gov (United States)

    Magri, Fabien; Inbar, Nimrod; Möller, Peter; Raggad, Marwan; Rödiger, Tino; Rosenthal, Eliahu; Shentsis, Izabela; Tzoufka, Kalliopi; Siebert, Christian

    2017-04-01

    The Lower Yarmouk Gorge (LYG) lies on the eastern margin of the lower Jordan Rift Valley (JRV), bounded to the south by the Ajlun and to the north by the Golan Heights. It allows the outflow of the Yarmouk drainage basin and flow into the Jordan River, a few kilometers south of Lake Tiberias. The main aquifer system of the LYG is built mostly of Cretaceous sandstones and carbonates confined by Maastrichtian aquiclude. Fissures allow hydraulic connections between the major water-bearing formations from Quaternary to Upper Cretaceous age. It is supposed that the gorge acts as the mixing zone of two crossing flow pathways: N-S from the Hermon Mountains and from the Ajlun Dome, and E-W from Jebel al Arab Mountain in Syria (also known as Huran Plateau or Yarmouk drainage basin). As a result, several springs can be found within the gorge. These are characterized by widespread temperatures (20 - 60 °C) which indicate that, beside the complex regional flow, also ascending thermal waters control the hydrologic behavior of the LYG. Previous simulations based on a conceptual simplified 3D model (Magri et al., 2016) showed that crossing flow paths result from the coexistence of convection, that can develop for example along NE-SW oriented faults within the gorge or in permeable aquifers below Maastrichtian aquiclude, and additional flow fields that are induced by the N-S topographic gradients. Here we present the first 3D hydrogeological model of the entire LYG that includes structural features based on actual logs and interpreted seismic lines from both Israeli and Jordanian territories. The model distinguishes seven units from upper Eocene to the Lower Triassic, accounting for major aquifers, aquicludes and deep-cutting faults. Recharges are implemented based on the numerical representation developed by Shentsis (1990) that considers relationships between mean annual rain and topographic elevation. The model reveals that topography-driven N-S and E-W flows strongly control

  9. The Three Gorges Dam: A great leap backward for China's electricity consumers and economy

    Energy Technology Data Exchange (ETDEWEB)

    Adams, P.; Ryder, G. [Probe International, Toronto, ON (Canada)

    1999-12-16

    Reasons why the Three Gorges Dam, the largest hydroelectric power project in the world, is not only an environmental disaster, but also an economically unsound undertaking for the Chinese economy are discussed. The thrust of the argument is that rapid advancement in technology, in combination with the economic reforms to decentralize electric power production in China, will allow private enterprise to be in direct competition with the Three Gorges (and other bid dam) projects. These factors, combined with the economic pressures resulting from the shutting down of money-losing state enterprises and consequently, a significant reduction in the demand for electricity, spell disaster for the big dam projects conceived during the centrally-planned, Maoist era. Because of the Three Gorges project's unusually large size, the outdated and unreliable power transmission networks in China, and because the local state transmission grids are not connected to China's national grid, the central government will have to invest some $ 30 billion over the next three years in a new national transmission grid. The aggregate result of these events will be that competition from cheaper, cleaner power producers (such as combined cycle power producers) will price the Three Gorges power out of the market by the time it is expected to go into production in 2009. Based on the assessment of reputable world economic and engineering organizations, Probe International recommends cancellation of the project to avoid environmental and economic disaster. 61 refs.

  10. [Spatial Distribution Characteristics of Different Species Mercury in Water Body of Changshou Lake in Three Gorges Reservoir Region].

    Science.gov (United States)

    Bai, Wei-yang; Zhang, Cheng; Zhao, Zheng; Tang, Zhen-ya; Wang, Ding-yong

    2015-08-01

    An investigation on the concentrations and the spatial distribution characteristics of different species of mercury in the water body of Changshou Lake in Three Gorges Reservoir region was carried out based on the AreGIS statistics module. The results showed that the concentration of the total mercury in Changshou Lake surface water ranged from 0.50 to 3.78 ng x L(-1), with an average of 1.51 ng x L(-1); the concentration of the total MeHg (methylmercury) ranged from 0.10 to 0.75 ng x L(-1), with an average of 0.23 ng x L(-1). The nugget effect value of total mercury in surface water (50.65%), dissolved mercury (49.80%), particulate mercury (29.94%) and the activity mercury (26.95%) were moderate spatial autocorrelation. It indicated that the autocorrelation was impacted by the intrinsic properties of sediments (such as parent materials and rocks, geological mineral and terrain), and on the other hand it was also disturbed by the exogenous input factors (such as aquaculture, industrial activities, farming etc). The nugget effect value of dissolved methylmercury (DMeHg) in Changshou lake surface water (3.49%) was less than 25%, showing significant strong spatial autocorrelation. The distribution was mainly controlled by environmental factors in water. The proportion of total MeHg in total Hg in Changshou Lake water reached 30% which was the maximum ratio of the total MeHg to total Hg in freshwater lakes and rivers. It implied that mercury was easily methylated in the environment of Chanashou Lake.

  11. Radiological audit of remedial action activities at the processing site, transfer site, and Cheney disposal site Grand Junction, Colorado: Audit date, August 9--11, 1993

    International Nuclear Information System (INIS)

    1993-08-01

    The Uranium Mill Tailing Remedial Action (UMTRA) Project's Technical Assistance Contractor (TAC) performed a radiological audit of the Remedial Action Contractor (RAC), MK-Ferguson and CWM Federal Environmental Services, Inc., at the processing site, transfer site, and Cheney disposal site in Grand Junction, Colorado. Jim Hylko and Bill James of the TAC conducted this audit August 9 through 11, 1993. Bob Cornish and Frank Bosiljevec represented the US Department of Energy (DOE). This report presents one programmatic finding, eleven site-specific observations, one good practice, and four programmatic observations

  12. Preliminary Magnetostratigraphic Study of the Split Mountain and Lower Imperial Groups, Split Mountain Gorge, Western Salton Trough, CA

    Science.gov (United States)

    Fluette, A. L.; Housen, B. A.; Dorsey, R. J.

    2004-12-01

    We present preliminary results of a magnetostratigraphic study of Miocene-Pliocene sedimentary rocks of the Split Mt. and lower Imperial Groups exposed in Split Mt. Gorge and eastern Fish Creek-Vallecito basin, western Salton Trough. Precise age control for the base of this thick section is needed to improve our understanding of the early history of extension-related subsidence in this region. The geologic setting and stratigraphic framework are known from previous work by Dibblee (1954, 1996), Woodard (1963), Kerr (1982), Winker (1987), Kerr and Kidwell (1991), Winker and Kidwell (1986; 1996), and others. We have analyzed Upper Miocene to lower Pliocene strata exposed in a conformable section in Split Mt. Gorge, including (in order from the base; nomenclature of Winker and Kidwell, 1996): (1) Split Mt. Group: Red Rock Fm alluvial sandstone; Elephant Trees alluvial conglomerate; and lower megabreccia unit; and (2) lower part of Imperial Group, including: Fish Creek Gypsum; proximal to distal turbidites of the Latrania Fm and Wind Caves Mbr of Deguynos Fm; upper megabreccia unit; marine mudstone and rhythmites of the Mud Hills Mbr (Deguynos Fm); and the basal part of the Yuha Mbr (Deguynos Fm). Measured thickness from the base of the Elephant Trees Cgl to the base of the Yuha Mbr is about 1050 m, consistent with previous measurements of Winker (1987). Paleomagnetic samples were collected at approximately 10 m intervals throughout this section. The upper portion of our sampled section overlaps with the lower part of the section sampled for magnetostratigraphic study by Opdyke et al. (1977) and Johnson et al. (1983). They interpreted the base of their section to be about 4.3 Ma, and calculated an average sedimentation rate of approximately 5.5 mm/yr for the lower part of their section. Good-quality preliminary results from 15 paleomagnetic sites distributed throughout our sampled section permit preliminary identification of 6 polarity zones. Based on regional mapping

  13. "Possible impacts of climate change on the Danube river along the Iron Gate gorge

    Science.gov (United States)

    Adamovic, M.

    2009-04-01

    The research was dedicated to foreseeing the possible impacts of climate change on water resources in eastern part of Serbia, along the Danube catchment. The Danube basin is in the eastern section of the considered RCM ( Regional climate model). For this purposes, the RCM EBU-POM according to the IPCC scenario A1B, was used in its representation of the hydrological balance over the Danube river basin along Iron Gate gorge, for the time frame 1961-1990 and 2071-2100. The Danube's catchment encompasses continental climate, as it is land-dominated by advection from the surrounding land areas. This part of Danube catchment is greatly affected by the Mediterranean climate, since the Danube runoff gives a relevant contribution of freshwater flux into the Mediterranean sea and it is dependent mostly on precipitated water of Mediterranean origin. On the other, the Dinaric-Balkan mountain chains in the west and the Carpathian mountain bow in the north and east, present distinctive morphological and climatic regions and barriers. The hydrological balance has been computed in two different, but in principle equivalent ways. The first approach, which has a more hydrological nuance, relies on establishing relationships between annual averages of the hydrological balance parameters (E, P, T) in order to get relevant coefficients. The second approach, which is more typically meteorological, relies on the calculation of the E for the time frame 2071-2100 by using the previous coefficients and getting runoff depth (h) and discharge (Q) as the final outputs. The results according to this model, show that the river flow of the Danube, in this part of its basin, will decrease over 50% with a great consequences to the dams Iron Gate I and II, their accumulations and ecosystems. Furthermore, if we take into account predictions made by IPCC which say that the south-east Europe will face temperature growth of 0.2 degrees in the next two decades for the range of SRES scenarios, makes the

  14. Differential regulation of the transcriptional activity of the glucocorticoid receptor through site-specific phosphorylation

    Directory of Open Access Journals (Sweden)

    Raj Kumar

    2008-08-01

    Full Text Available Raj Kumar1, William J Calhoun21Division of Gastroenterology; 2Division of Allergy, Pulmonary, Immunology, Critical Care, and Sleep (APICS, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USAAbstract: Post-translational modifications such as phosphorylation are known to play an important role in the gene regulation by the transcription factors including the nuclear hormone receptor superfamily of which the glucocorticoid receptor (GR is a member. Protein phosphorylation often switches cellular activity from one state to another. Like many other transcription factors, the GR is a phosphoprotein, and phosphorylation plays an important role in the regulation of GR activity. Cell signaling pathways that regulate phosphorylation of the GR and its associated proteins are important determinants of GR function under various physiological conditions. While the role of many phosphorylation sites in the GR is still not fully understood, the role of others is clearer. Several aspects of transcription factor function, including DNA binding affinity, interaction of transactivation domains with the transcription initiation complex, and shuttling between the cytoplasmic compartments, have all been linked to site-specific phosphorylation. All major phosphorylation sites in the human GR are located in the N-terminal domain including the major transactivation domain, AF1. Available literature clearly indicates that many of these potential phosphorylation sites are substrates for multiple kinases, suggesting the potential for a very complex regulatory network. Phosphorylated GR interacts favorably with critical coregulatory proteins and subsequently enhances transcriptional activity. In addition, the activities and specificities of coregulators may be subject to similar regulation by phosphorylation. Regulation of the GR activity due to phosphorylation appears to be site-specific and dependent upon specific cell signaling cascade

  15. Human glutaminyl cyclase and bacterial zinc aminopeptidase share a common fold and active site

    Directory of Open Access Journals (Sweden)

    Misquitta Stephanie A

    2004-02-01

    Full Text Available Abstract Background Glutaminyl cyclase (QC forms the pyroglutamyl residue at the amino terminus of numerous secretory peptides and proteins. We previously proposed the mammalian QC has some features in common with zinc aminopeptidases. We now have generated a structural model for human QC based on the aminopeptidase fold (pdb code 1AMP and mutated the apparent active site residues to assess their role in QC catalysis. Results The structural model proposed here for human QC, deposited in the protein databank as 1MOI, is supported by a variety of fold prediction programs, by the circular dichroism spectrum, and by the presence of the disulfide. Mutagenesis of the six active site residues present in both 1AMP and QC reveal essential roles for the two histidines (140 and 330, QC numbering and the two glutamates (201 and 202, while the two aspartates (159 and 248 appear to play no catalytic role. ICP-MS analysis shows less than stoichiometric zinc (0.3:1 in the purified enzyme. Conclusions We conclude that human pituitary glutaminyl cyclase and bacterial zinc aminopeptidase share a common fold and active site residues. In contrast to the aminopeptidase, however, QC does not appear to require zinc for enzymatic activity.

  16. Synthesis and characterization of 18F-labeled active site inhibited factor VII (ASIS)

    DEFF Research Database (Denmark)

    Erlandsson, Maria; Nielsen, Carsten Haagen; Jeppesen, Troels Elmer

    2015-01-01

    Activated factor VII blocked in the active site with Phe-Phe-Arg-chloromethyl ketone (active site inhibited factor VII (ASIS)) is a 50-kDa protein that binds with high affinity to its receptor, tissue factor (TF). TF is a transmembrane glycoprotein that plays an important role in, for example......, thrombosis, metastasis, tumor growth, and tumor angiogenesis. The aim of this study was to develop an 18F-labeled ASIS derivative to assess TF expression in tumors. Active site inhibited factor VII was labeled using N-succinimidyl-4-[18F]fluorobenzoate, and the [18F]ASIS was purified on a PD-10 desalting...... column. The radiochemical yield was 25 ± 6%, the radiochemical purity was >97%, and the pseudospecific radioactivity was 35 ± 9 GBq/µmol. The binding efficacy was evaluated in pull-down experiments, which monitored the binding of unlabeled ASIS and [18F]ASIS to TF and to a specific anti-factor VII...

  17. RCRA and CERCLA requirements affecting cleanup activities at a federal facility superfund site

    International Nuclear Information System (INIS)

    Walsh, T.J.

    1994-01-01

    The Fernald Environmental Management Project (FEMP) achieved success on an integrated groundwater monitoring program which addressed both RCRA and CERCLA requirements. The integrated plan resulted in a cost savings of approximately $2.6 million. At present, the FEMP is also working on an integrated closure process to address Hazardous Waste Management Units (HWMUs) at the site. To date, Ohio EPA seems willing to discuss an integrated program with some stipulations. If an integrated program is implemented, a cost savings of several million dollars will be realized since the CERCLA documents can be used in place of a RCRA closure plan. The success of an integrated program at the FEMP is impossible without the support of DOE and the regulators. Since DOE is an owner/operator of the facility and Ohio EPA regulates hazardous waste management activities at the FEMP, both parties must be satisfied with the proposed integration activities. Similarly, US EPA retains CERCLA authority over the site along with a signed consent agreement with DOE, which dictates the schedule of the CERCLA activities. Another federal facility used RCRA closure plans to satisfy CERCLA activities. This federal facility was in a different US EPA Region than the FEMP. While this approach was successful for this site, an integrated approach was required at the FEMP because of the signed Consent Agreement and Consent Decree. For federal facilities which have a large number of HWMUs along with OUs, an integrated approach may result in a timely and cost-effective cleanup

  18. Progress report on decommissioning activities at the Fernald Environmental Management Project (FEMP) site

    International Nuclear Information System (INIS)

    1998-01-01

    The Fernald Environmental Management Project (FEMP), is located about 18 miles northwest of Cincinnati, Ohio. Between 1953 and 1989, the facility, then called the Feed Material Production Center or FMPC, produced uranium metal products used in the eventual production of weapons grade material for use by other US Department of Energy (DOE) sites. In 1989, FMPC's production was suspended by the federal government in order to focus resources on environmental restoration versus defense production. In 1992, Fluor Daniel Fernald assumed responsibility for managing all cleanup activities at the FEMP under contract to the DOE. In 1990, as part of the remediation effort, the site was divided into five operable units based on physical proximity of contaminated areas, similar amounts of types of contamination, or the potential for a similar technology to be used in cleanup activities. This report continues the outline of the decontamination and decommissioning (D and D) activities at the FEMP site Operable Unit 3 (OU3) and provides an update on the status of the decommissioning activities. OU3, the Facilities Closure and Demolition Project, involves the remediation of more than 200 uranium processing facilities. The mission of the project is to remove nuclear materials stored in these buildings, then perform the clean out of the buildings and equipment, and decontaminate and dismantle the facilities

  19. Role of a cysteine residue in the active site of ERK and the MAPKK family

    International Nuclear Information System (INIS)

    Ohori, Makoto; Kinoshita, Takayoshi; Yoshimura, Seiji; Warizaya, Masaichi; Nakajima, Hidenori; Miyake, Hiroshi

    2007-01-01

    Kinases of mitogen-activated protein kinase (MAPK) cascades, including extracellular signal-regulated protein kinase (ERK), represent likely targets for pharmacological intervention in proliferative diseases. Here, we report that FR148083 inhibits ERK2 enzyme activity and TGFβ-induced AP-1-dependent luciferase expression with respective IC 50 values of 0.08 and 0.05 μM. FR265083 (1'-2' dihydro form) and FR263574 (1'-2' and 7'-8' tetrahydro form) exhibited 5.5-fold less and no activity, respectively, indicating that both the α,β-unsaturated ketone and the conformation of the lactone ring contribute to this inhibitory activity. The X-ray crystal structure of the ERK2/FR148083 complex revealed that the compound binds to the ATP binding site of ERK2, involving a covalent bond to Sγ of ERK2 Cys166, hydrogen bonds with the backbone NH of Met108, Nζ of Lys114, backbone C=O of Ser153, Nδ2 of Asn154, and hydrophobic interactions with the side chains of Ile31, Val39, Ala52, and Leu156. The covalent bond motif in the ERK2/FR148083 complex assures that the inhibitor has high activity for ERK2 and no activity for other MAPKs such as JNK1 and p38MAPKα/β/γ/δ which have leucine residues at the site corresponding to Cys166 in ERK2. On the other hand, MEK1 and MKK7, kinases of the MAPKK family which also can be inhibited by FR148083, contain a cysteine residue corresponding to Cys166 of ERK2. The covalent binding to the common cysteine residue in the ATP-binding site is therefore likely to play a crucial role in the inhibitory activity for these MAP kinases. These findings on the molecular recognition mechanisms of FR148083 for kinases with Cys166 should provide a novel strategy for the pharmacological intervention of MAPK cascades

  20. Active Site Flexibility as a Hallmark for Efficient PET Degradation by I. sakaiensis PETase.

    Science.gov (United States)

    Fecker, Tobias; Galaz-Davison, Pablo; Engelberger, Felipe; Narui, Yoshie; Sotomayor, Marcos; Parra, Loreto P; Ramírez-Sarmiento, César A

    2018-03-27

    Polyethylene terephthalate (PET) is one of the most-consumed synthetic polymers, with an annual production of 50 million tons. Unfortunately, PET accumulates as waste and is highly resistant to biodegradation. Recently, fungal and bacterial thermophilic hydrolases were found to catalyze PET hydrolysis with optimal activities at high temperatures. Strikingly, an enzyme from Ideonella sakaiensis, termed PETase, was described to efficiently degrade PET at room temperature, but the molecular basis of its activity is not currently understood. Here, a crystal structure of PETase was determined at 2.02 Å resolution and employed in molecular dynamics simulations showing that the active site of PETase has higher flexibility at room temperature than its thermophilic counterparts. This flexibility is controlled by a novel disulfide bond in its active site, with its removal leading to destabilization of the catalytic triad and reduction of the hydrolase activity. Molecular docking of a model substrate predicts that PET binds to PETase in a unique and energetically favorable conformation facilitated by several residue substitutions within its active site when compared to other enzymes. These computational predictions are in excellent agreement with recent mutagenesis and PET film degradation analyses. Finally, we rationalize the increased catalytic activity of PETase at room temperature through molecular dynamics simulations of enzyme-ligand complexes for PETase and other thermophilic PET-degrading enzymes at 298, 323, and 353 K. Our results reveal that both the binding pose and residue substitutions within PETase favor proximity between the catalytic residues and the labile carbonyl of the substrate at room temperature, suggesting a more favorable hydrolytic reaction. These results are valuable for enabling detailed evolutionary analysis of PET-degrading enzymes and for rational design endeavors aiming at increasing the efficiency of PETase and similar enzymes toward plastic

  1. Active-site titration analysis of surface influence on immobilized Candida antarctica Lipase B activity

    Science.gov (United States)

    Matrix morphology and surface polarity effects were investigated for Candida antarctica lipase B immobilization. Measurements of the amount of lipase immobilized (bicinchoninic acid method) and the catalyst’s tributyrin hydrolysis activity, coupled with a determination of the lipase’s functional fr...

  2. Linde FUSRAP Site Remediation: Engineering Challenges and Solutions of Remedial Activities on an Active Industrial Facility - 13506

    International Nuclear Information System (INIS)

    Beres, Christopher M.; Fort, E. Joseph; Boyle, James D.

    2013-01-01

    The Linde FUSRAP Site (Linde) is located in Tonawanda, New York at a major research and development facility for Praxair, Inc. (Praxair). Successful remediation activities at Linde combines meeting cleanup objectives of radiological contamination while minimizing impacts to Praxair business operations. The unique use of Praxair's property coupled with an array of active and abandoned utilities poses many engineering and operational challenges; each of which has been overcome during the remedial action at Linde. The U.S. Army Corps of Engineers - Buffalo District (USACE) and CABRERA SERVICES, INC. (CABRERA) have successfully faced engineering challenges such as relocation of an aboveground structure, structural protection of an active water line, and installation of active mechanical, electrical, and communication utilities to perform remediation. As remediation nears completion, continued success of engineering challenges is critical as remaining activities exist in the vicinity of infrastructure essential to business operations; an electrical substation and duct bank providing power throughout the Praxair facility. Emphasis on engineering and operations through final remediation and into site restoration will allow for the safe and successful completion of the project. (authors)

  3. Linde FUSRAP Site Remediation: Engineering Challenges and Solutions of Remedial Activities on an Active Industrial Facility - 13506

    Energy Technology Data Exchange (ETDEWEB)

    Beres, Christopher M.; Fort, E. Joseph [Cabrera Services, Inc., 473 Silver Lane, East Hartford, CT 06118 (United States); Boyle, James D. [United States Army Corps of Engineers - Buffalo, 1776 Niagara Street, Buffalo, NY 14207 (United States)

    2013-07-01

    The Linde FUSRAP Site (Linde) is located in Tonawanda, New York at a major research and development facility for Praxair, Inc. (Praxair). Successful remediation activities at Linde combines meeting cleanup objectives of radiological contamination while minimizing impacts to Praxair business operations. The unique use of Praxair's property coupled with an array of active and abandoned utilities poses many engineering and operational challenges; each of which has been overcome during the remedial action at Linde. The U.S. Army Corps of Engineers - Buffalo District (USACE) and CABRERA SERVICES, INC. (CABRERA) have successfully faced engineering challenges such as relocation of an aboveground structure, structural protection of an active water line, and installation of active mechanical, electrical, and communication utilities to perform remediation. As remediation nears completion, continued success of engineering challenges is critical as remaining activities exist in the vicinity of infrastructure essential to business operations; an electrical substation and duct bank providing power throughout the Praxair facility. Emphasis on engineering and operations through final remediation and into site restoration will allow for the safe and successful completion of the project. (authors)

  4. Large zinc cation occupancy of octahedral sites in mechanically activated zinc ferrite powders

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, S. A. [Center for Electromagnetic Research, Northeastern University, Boston, Massachusetts 02115 (United States); Harris, V. G. [Complex Materials Section, Code 6342, Naval Research Laboratory, Washington, DC 20375 (United States); Hamdeh, H. H. [Department of Physics, Wichita State University, Wichita, Kansas 67260 (United States); Ho, J. C. [Department of Physics, Wichita State University, Wichita, Kansas 67260 (United States)

    2000-05-08

    The cation site occupancy of a mechanically activated nanocrystalline zinc ferrite powder was determined as (Zn{sub 0.55}{sup 2+}Fe{sub 0.18}{sup 3+}){sub tet}[Zr{sub 0.45}{sup 2+}Fe{sub 1.82}{sup 3+}]{sub oct}O{sub 4} through analysis of extended x-ray absorption fine structure measurements, showing a large redistribution of cations between sites compared to normal zinc ferrite samples. The overpopulation of cations in the octahedral sites was attributed to the ascendance in importance of the ionic radii over the crystal energy and bonding coordination in determining which interstitial sites are occupied in this structurally disordered powder. Slight changes are observed in the local atomic environment about the zinc cations, but not the iron cations, with respect to the spinel structure. The presence of Fe{sup 3+} on both sites is consistent with the measured room temperature magnetic properties. (c) 2000 American Institute of Physics.

  5. Anti-nuclear activities and critics concerning nuclear power plant sites

    International Nuclear Information System (INIS)

    Rhee, We-Beg

    2000-01-01

    Korea has dynamic nuclear power expansion programs, operating 16 nuclear units producing 13710 MW in total located on 4 different sites. Last year, nuclear power supplied over 40 % of national total electricity demands. In 1998, Korean government initiated re-designation work investigating circumstance changes to rule out the unnecessary sites in consideration of a long-term power supply. Korean government has determined to expand the Ulchin site and to designate one point of Woolju county as a new candidate site, and ruled out the rest candidate sites at the end of 1998. About such a governmental measure, the two areas show different reactions. Ulchin where nuclear power plant has been operated safely for about 10 years was likely to accept the governmental determination in spite of some opposition and called for several financial supports for local development. WooIju county, however, showed a strong opposition among local environmental groups and autonomous politicians, and they presented a variety of anti-nuclear activities including demonstrations mainly at the neighbouring metropolis, Ulsan city

  6. Soil pollution with trace elements at selected sites in Romania studied by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Pantelica, A.; Carmo Freitas, M. do; Ene, A.; Steinnes, E.

    2013-01-01

    Instrumental neutron activation analysis (INAA) was used to determine concentrations of 42 elements in samples of surface soil collected at seven sites polluted from various anthropogenic activities and a control site in a relatively clean area. Elements studied were Ag, Al, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Eu, Fe, Gd, Hf, Hg, K, La, Lu, Mg, Mn, Mo, Na, Nd, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Ti, U, V, W, Yb, Zn, and Zr. The results are compared with data for trace elements atmospheric deposition in lichen transplants from the same sites. The most severe soil contamination was observed at Copsa Mica from non-ferrous metallurgy. Appreciable soil contamination was also indicated at Baia Mare (non-ferrous mining and metallurgy), Deva (coal-fired power plant, cement and building materials industry), Galati (ferrous metallurgy), Magurele and Afumati (general urban pollution), and Oradea (chemical and light industries). In most cases excessive levels of toxic metals in soils matched correspondingly high values in lichen transplants. Compared to Romanian norms, legal upper limits were exceeded for Zn and Cd at Copsa Mica. Also, As and Sb occurred in excessive levels at given sites. (orig.)

  7. Soil pollution with trace elements at selected sites in Romania studied by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Pantelica, A. [Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), Magurele, Ilfov County (Romania); Carmo Freitas, M. do [Technological and Nuclear Institute (ITN), Sacavem (Portugal); Ene, A. [Dunarea de Jos Univ. of Galati (Romania). Dept. of Chemistry, Physics and Environment; Steinnes, E. [Norwegian Univ. of Science and Technology, Trondheim (Norway). Dept. of Chemistry

    2013-03-01

    Instrumental neutron activation analysis (INAA) was used to determine concentrations of 42 elements in samples of surface soil collected at seven sites polluted from various anthropogenic activities and a control site in a relatively clean area. Elements studied were Ag, Al, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Eu, Fe, Gd, Hf, Hg, K, La, Lu, Mg, Mn, Mo, Na, Nd, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Ti, U, V, W, Yb, Zn, and Zr. The results are compared with data for trace elements atmospheric deposition in lichen transplants from the same sites. The most severe soil contamination was observed at Copsa Mica from non-ferrous metallurgy. Appreciable soil contamination was also indicated at Baia Mare (non-ferrous mining and metallurgy), Deva (coal-fired power plant, cement and building materials industry), Galati (ferrous metallurgy), Magurele and Afumati (general urban pollution), and Oradea (chemical and light industries). In most cases excessive levels of toxic metals in soils matched correspondingly high values in lichen transplants. Compared to Romanian norms, legal upper limits were exceeded for Zn and Cd at Copsa Mica. Also, As and Sb occurred in excessive levels at given sites. (orig.)

  8. Den site activity patterns of adult male and female swift foxes, Vulpes velox, in Northwestern Texas

    Science.gov (United States)

    Lemons, P.R.; Ballard, W.B.; Sullivan, R.M.; Sovada, M.A.

    2003-01-01

    Activity of Swift Foxes (Vulpes velox) at den sites was studied in northwestern Texas during pup rearing seasons in 2000 and 2001 to determine role of males in parental care. Twenty-four percent of radio-collared females with a potential to breed successfully raised pups to eight weeks of age. We intensively monitored presence and absence of male and female Swift Foxes at two den sites each year. Females were present >2.6 times more at den sites than males during the pup rearing season. Female and male Swift Foxes largely stayed at dens during diurnal hours and were active away from dens during nocturnal and crepuscular hours. Females and males spent 12.4% and 3.0% more time at dens before pups emerged, than after pups emerged, respectively. Following depredation of one male parent, the female spent 29% less time at the den site. Decrease in time spent at the den by the female following loss of her mate suggested that loss of one parent might severely impact recruitment of Swift Foxes. Our observations indicated that intense Coyote (Canis latrans) depredation may severely impact pup-rearing success as well as the parental care within Swift Fox family groups.

  9. Improving the activity of the subtilisin nattokinase by site-directed mutagenesis and molecular dynamics simulation.

    Science.gov (United States)

    Weng, Meizhi; Deng, Xiongwei; Bao, Wei; Zhu, Li; Wu, Jieyuan; Cai, Yongjun; Jia, Yan; Zheng, Zhongliang; Zou, Guolin

    2015-09-25

    Nattokinase (NK), a bacterial serine protease from Bacillus subtilis var. natto, is a potential cardiovascular drug exhibiting strong fibrinolytic activity. To broaden its commercial and medical applications, we constructed a single-mutant (I31L) and two double-mutants (M222A/I31L and T220S/I31L) by site-directed mutagenesis. Active enzymes were expressed in Escherichia coli with periplasmic secretion and were purified to homogeneity. The kinetic parameters of enzymes were examined by spectroscopy assay and isothermal titration calorimetry (ITC), and their fibrinolytic activities were determined by fibrin plate method. The substitution of Leu(31) for Ile(31) resulted in about 2-fold enhancement of catalytic efficiency (Kcat/KM) compared with wild-type NK. The specific activities of both double-mutants (M222A/I31L and T220S/I31L) were significantly increased when compared with the single-mutants (M222A and T220S) and the oxidative stability of M222A/I31L mutant was enhanced with respect to wild-type NK. This study demonstrates the feasibility of improving activity of NK by site-directed mutagenesis and shows successful protein engineering cases to improve the activity of NK as a potent therapeutic agent. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Use of the Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP) for site cleanup activities

    International Nuclear Information System (INIS)

    Griggs, J.

    1999-01-01

    MARLAP is being developed as a multi-agency guidance manual for project managers and radioanalytical laboratories. The document uses a performance based approach and will provide guidance and a framework to assure that laboratory radioanalytical data meets the specific project or program needs and requirements. MARLAP supports a wide range of data collection activities including site characterization and compliance demonstration activities. Current participants include: US Environmental Protection Agency (EPA), US Department of Energy (DOE), US Nuclear Regulatory Commission (NRC), US Department of Defense (DoD), US National Institutes of Standards and Technology (NIST), US Geologic Survey (USGS), US Food and Drug Administration (FDA), Commonwealth of Kentucky, and the State of California. MARLAP is the radioanalytical laboratory counterpart to the Multi-Agency Radiological Survey and Site Investigation Manual (MARSSIM). MARLAP is currently in a preliminary draft stage. (author)

  11. Twinning in fcc lattice creates low-coordinated catalytically active sites in porous gold

    Energy Technology Data Exchange (ETDEWEB)

    Krajčí, Marian [Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84511 Bratislava (Slovakia); Kameoka, Satoshi; Tsai, An-Pang [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan)

    2016-08-28

    We describe a new mechanism for creation of catalytically active sites in porous gold. Samples of porous gold prepared by de-alloying Al{sub 2}Au exhibit a clear correlation between the catalytic reactivity towards CO oxidation and structural defects in the fcc lattice of Au. We have found that on the stepped (211) surfaces quite common twin boundary defects in the bulk structure of porous gold can form long close-packed rows of atoms with the coordination number CN = 6. DFT calculations confirm that on these low-coordinated Au sites dioxygen chemisorbs and CO oxidation can proceed via the Langmuir–Hinshelwood mechanism with the activation energy of 37 kJ/mol or via the CO–OO intermediate with the energy barrier of 19 kJ/mol. The existence of the twins in porous gold is stabilized by the surface energy.

  12. Visualization of the Differential Transition State Stabilization within the Active Site Environment

    Directory of Open Access Journals (Sweden)

    Jerzy Leszczynski

    2004-05-01

    Full Text Available Abstract: Increasing interest in the enzymatic reaction mechanisms and in the nature of catalytic effects in enzymes causes the need of appropriate visualization methods. A new interactive method to investigate catalytic effects using differential transition state stabilization approach (DTSS [1, 2] is presented. The catalytic properties of the active site of cytidine deaminase (E.C. 3.5.4.5 is visualized in the form of differential electrostatic properties. The visualization was implemented using scripting interface of VMD [3]. Cumulative Atomic Multipole Moments (CAMM [4,5,6] were utilized for efficient yet accurate evaluation of the electrostatic properties. The implementation is efficient enough for interactive presentation of catalytic effects in the active site of the enzyme due to transition state or substrate movement. This system of visualization of DTTS approach can be potentially used to validate hypotheses regarding the catalytic mechanism or to study binding properties of transition state analogues.

  13. {sup 13}C-Methyl isocyanide as an NMR probe for cytochrome P450 active sites

    Energy Technology Data Exchange (ETDEWEB)

    McCullough, Christopher R.; Pullela, Phani Kumar [Marquette University, Chemical Proteomics Facility at Marquette, Department of Chemistry (United States); Im, Sang-Choul; Waskell, Lucy [University of Michigan and VA Medical Center, Department of Anesthesiology (United States); Sem, Daniel S. [Marquette University, Chemical Proteomics Facility at Marquette, Department of Chemistry (United States)], E-mail: Daniel.sem@marquette.edu

    2009-03-15

    The cytochromes P450 (CYPs) play a central role in many biologically important oxidation reactions, including the metabolism of drugs and other xenobiotic compounds. Because they are often assayed as both drug targets and anti-targets, any tools that provide: (a) confirmation of active site binding and (b) structural data, would be of great utility, especially if data could be obtained in reasonably high throughput. To this end, we have developed an analog of the promiscuous heme ligand, cyanide, with a {sup 13}CH{sub 3}-reporter attached. This {sup 13}C-methyl isocyanide ligand binds to bacterial (P450cam) and membrane-bound mammalian (CYP2B4) CYPs. It can be used in a rapid 1D experiment to identify binders, and provides a qualitative measure of structural changes in the active site.

  14. Interaction of mining activities and aquatic environment: A review from Greek mine sites.

    Science.gov (United States)

    Vasileiou, Eleni; Kallioras, Andreas

    2016-04-01

    In Greece a significant amount of mineral and ore deposits have been recorded accompanied by large industrial interest and a long mining history. Today many active and/or abandoned mine sites are scattered within the country; while mining activities take place in different sites for exploiting various deposits (clay, limestone, slate, gypsum, kaolin, mixed sulphide ores (lead, zinc, olivine, pozzolan, quartz lignite, nickel, magnesite, aluminum, bauxite, gold, marbles etc). The most prominent recent ones are: (i) the lignite exploitation that is extended in the area of Ptolemais (Western Macedonia) and Megalopolis (Central Peloponnese); and (ii) the major bauxite deposits located in central Greece within the Parnassos-Ghiona geotectonic zone and on Euboea Island. In the latter area, significant ores of magnesite were exploited and mixed sulphide ores. Centuries of intensive mining exploitation and metallurgical treatment of lead-silver deposits in Greece, have also resulted in significant abandoned sites, such as the one in Lavrion. Mining activities in Lavrio, were initiated in ancient times and continued until the 1980s, resulting in the production of significant waste stockpiles deposited in the area, crucial for the local water resources. Ιn many mining sites, environmental pressures are also recorded after the mine closure to the aquatic environment, as the surface waters flow through waste dump areas and contaminated soils. This paper aims to the geospatial visualization of the mining activities in Greece, in connection to their negative (surface- and/or ground-water pollution; overpumping due to extensive dewatering practices) or positive (enhanced groundwater recharge; pit lakes, improvement of water budget in the catchment scale) impacts on local water resources.

  15. Generation of 3D templates of active sites of proteins with rigid prosthetic groups

    OpenAIRE

    Nebel, Jean-Christophe

    2006-01-01

    MOTIVATION: With the increasing availability of protein structures, the generation of biologically meaningful 3D patterns from the simultaneous alignment of several protein structures is an exciting prospect: active sites could be better understood, protein functions and protein 3D structures could be predicted more accurately. Although patterns can already be generated at the fold and topological levels, no system produces high-resolution 3D patterns including atom and cavity positions. To a...

  16. Disposal Activities and the Unique Waste Streams at the Nevada National Security Site (NNSS)

    International Nuclear Information System (INIS)

    Arnold, P.

    2012-01-01

    This slide show documents waste disposal at the Nevada National Security Site. Topics covered include: radionuclide requirements for waste disposal; approved performance assessment (PA) for depleted uranium disposal; requirements; program approval; the Waste Acceptance Review Panel (WARP); description of the Radioactive Waste Acceptance Program (RWAP); facility evaluation; recent program accomplishments, nuclear facility safety changes; higher-activity waste stream disposal; and, large volume bulk waste streams

  17. Comment on "Active sites for CO2 hydrogenation to methanol on Cu/ZnO catalysts"

    DEFF Research Database (Denmark)

    Nakamura, Junji; Fujitani, Tadahiro; Kuld, Sebastian

    2017-01-01

    Kattel et al (Reports, 24 March 2017, p. 1296) report that a zinc on copper (Zn/Cu) surface undergoes oxidation to zinc oxide/copper (ZnO/Cu) during carbon dioxide (CO2) hydrogenation to methanol and conclude that the Cu-ZnO interface is the active site for methanol synthesis. Similar experiments...... conducted two decades ago by Fujitani and Nakamura et al demonstrated that Zn is attached to formate rather than being fully oxidized....

  18. Geological status of NWTS repository siting activities in the paradox basin

    International Nuclear Information System (INIS)

    Frazier, N.A.; Conwell, F.R.

    1981-01-01

    Emplacement of waste packages in mined geological repositories is one method being evaluated for isolating high-level nuclear wastes. Granite, dome salt, tuff, basalt and bedded salt are among the rock types being investigated. Described in this paper is the status of geological activities in the Paradox Basin of Utah and Colorado, one region being explored as a part of the National Waste Terminal Storage (NWTS) program to site a geological repository in bedded salt

  19. Human activity and landscape change at Adjiyska Vodenitsa, central Bulgaria

    Science.gov (United States)

    Chiverrell, R. C.; Archibald, Z.

    2009-04-01

    The Classical and early Hellenistic settlement located at Adjiyska Vodenitsa, near Vetren, in the centre of ancient Thrace, is somewhat unusual in displaying well-preserved evidence for the commercial and cultural interactions associated with a river port. The settlement evolved through a series of phases, with traces of activity emerging around the beginning of the fifth, advancing to a progressive close in the second century BCE. The settlement at Adjiyska Vodenitsa owed its raison d'être to river traffic, with the river as the primary means for importing commodities (non-local amphorae and roof tiles). The Pistiros inscription indicates that overland traffic was also important, presumably over the Rhodopes Mountains to the south. The relationship between the site and the Maritsa River is thus important. Located towards the head of the Maritsa basin downstream of the Momina Klissoura gorge near Belovo, the settlement is perched on a steeply-edged toe of the Vetren tributary alluvial fan, with the bluff trimmed by the migrating River Maritsa. The site is c.12-14 metres above the current bed of the River Maritsa, high and dry away from contemporary flooding, intriguing given evidence for flooding during occupation. The fluvial system has clearly been dynamic and changed much during the last 3000 years. Changes in the Maritsa have been constrained with radiocarbon ages obtained for two fan terrace levels. Active channel and overbank environments of the higher B1 terrace are dated to c. 520-400 cal. BC and provide a terminus post quem for the incision to the lower terrace (B2). The radiocarbon dating of basal contexts from the lower terrace palaeo-channels provides a terminus ante quem for abandonment of the higher terrace of cal. AD 1010-1150. Thus basal lowering and a shift to greater lateral channel activity appear to coincide with the abandonment of Adjiyska Vodenitsa. Upstream of the Momina Klissoura Gorge evidence for heightened geomorphic activity probably

  20. Characterization of active-site residues of the NIa protease from tobacco vein mottling virus.

    Science.gov (United States)

    Hwang, D C; Kim, D H; Lee, J S; Kang, B H; Han, J; Kim, W; Song, B D; Choi, K Y

    2000-10-31

    Nuclear inclusion a (NIa) protease of tobacco vein mottling virus is responsible for the processing of the viral polyprotein into functional proteins. In order to identify the active-site residues of the TVMV NIa protease, the putative active-site residues, His-46, Asp-81 and Cys-151, were mutated individually to generate H46R, H46A, D81E, D81N, C151S, and C151A, and their mutational effects on the proteolytic activities were examined. Proteolytic activity was completely abolished by the mutations of H46R, H46A, D81N, and C151A, suggesting that the three residues are crucial for catalysis. The mutation of D81E decreased kcat marginally by about 4.7-fold and increased Km by about 8-fold, suggesting that the aspartic acid at position 81 is important for substrate binding but can be substituted by glutamate without any significant decrease in catalysis. The replacement of Cys-151 by Ser to mimic the catalytic triad of chymotrypsin-like serine protease resulted in the drastic decrease in kcat by about 1,260-fold. This result might be due to the difference of the active-site geometry between the NIa protease and chymotrypsin. The protease exhibited a bell-shaped pH-dependent profile with a maximum activity approximately at pH 8.3 and with the abrupt changes at the respective pKa values of approximately 6.6 and 9.2, implying the involvement of a histidine residue in catalysis. Taken together, these results demonstrate that the three residues, His-46, Asp-81, and Cys-151, play a crucial role in catalysis of the TVMV NIa protease.

  1. Climate-informed flood frequency analysis based on Bayesian theory and teleconnection for the Three Gorges Dam (TGD)

    Science.gov (United States)

    DONG, Q.; Zhang, X.; Lall, U.; Sang, Y. F.; Xie, P.

    2017-12-01

    With the current global climate changing and human activities intensifying, the uncertainties and danger of floods increased significantly. However, the current flood frequency analysis is still based on the stationary assumption. This assumption not only limits the benefits of the water conservancy projects, but also brings hazard because it ignores the risk of flooding under climate change. In this paper, we relax the stationary hypothesis in the flood frequency analysis model based on the teleconnection and use the intrinsic relation of flood elements to improve the annual flood frequency results by Bayesian inference approaches. Daily discharges of the the Three Gorges Dam(TGD) in 1953-2013 years are used as an example. Firstly, according to the linear correlation between the climate indices and the distribution parameters, the prior distributions of peak and volume are established with the selected large scale climate predictors. After that, by using the copula function and predictands, the conditional probability function of peak and volume is obtained. Then, the Bayesian theory links the prior distributions and conditional distributions and get the posterior distributions. We compare the difference under different prior distributions and find the optimal flood frequency distribution model. Finally, we discuss the impact of dynamic flood frequency analysis on the plan and management of hydraulic engineering. The results show that compared with the prior probability, the posterior probability considering the correlation of the flood elements is more accurate and the uncertainty is smaller. And the dynamic flood frequency model has a great impact on the management of the existing hydraulic engineering, which can improve the engineering operation benefit and reducing its flood risk, but it nearly didn't influence the plan of hydraulic engineering. The study of this paper is helpful to the dynamic flood risk management of TGD, and provide reference for the

  2. Revegetation of the riparian zone of the Three Gorges Dam Reservoir leads to increased soil bacterial diversity.

    Science.gov (United States)

    Ren, Qingshui; Li, Changxiao; Yang, Wenhang; Song, Hong; Ma, Peng; Wang, Chaoying; Schneider, Rebecca L; Morreale, Stephen J

    2018-06-06

    As one of the most active components in soil, bacteria can affect soil physicochemical properties, its biological characteristics, and even its quality and health. We characterized dynamics of the soil bacterial diversity in planted (with Taxodium distichum) and unplanted soil in the riparian zone of the Three Gorges Dam Reservoir (TGDR), in southwestern China, in order to accurately quantify the changes in long-term soil bacterial community structure after revegetation. Measurements were taken annually in situ in the TGDR over the course of 5 years, from 2012 to 2016. Soil chemical properties and bacterial diversity were analyzed in both the planted and unplanted soil. After revegetation, the soil chemical properties in planted soil were significantly different than in unplanted soil. The effects of treatment, time, and the interaction of both time and treatment had significant impacts on most diversity indices. Specifically, the bacterial community diversity indices in planted soil were significantly higher and more stable than that in unplanted soil. The correlation analyses indicated that the diversity indices correlated with the pH value, organic matter, and soil available nutrients. After revegetation in the riparian zone of the TGDR, the soil quality and health is closely related to the observed bacterial diversity, and a higher bacterial diversity avails the maintenance of soil functionality. Thus, more reforestation should be carried out in the riparian zone of the TGDR, so as to effectively mitigate the negative ecological impacts of the dam. Vegetating the reservoir banks with Taxodium distichum proved successful, but planting mixed stands of native tree species could promote even higher riparian soil biodiversity and improved levels of ecosystem functioning within the TGDR.

  3. Discovery and Characterization of Non-ATP Site Inhibitors of the Mitogen Activated Protein (MAP) Kinases

    Energy Technology Data Exchange (ETDEWEB)

    Comess, Kenneth M.; Sun, Chaohong; Abad-Zapatero, Cele; Goedken, Eric R.; Gum, Rebecca J.; Borhani, David W.; Argiriadi, Maria; Groebe, Duncan R.; Jia, Yong; Clampit, Jill E.; Haasch, Deanna L.; Smith, Harriet T.; Wang, Sanyi; Song, Danying; Coen, Michael L.; Cloutier, Timothy E.; Tang, Hua; Cheng, Xueheng; Quinn, Christopher; Liu, Bo; Xin, Zhili; Liu, Gang; Fry, Elizabeth H.; Stoll, Vincent; Ng, Teresa I.; Banach, David; Marcotte, Doug; Burns, David J.; Calderwood, David J.; Hajduk, Philip J. (Abbott)

    2012-03-02

    Inhibition of protein kinases has validated therapeutic utility for cancer, with at least seven kinase inhibitor drugs on the market. Protein kinase inhibition also has significant potential for a variety of other diseases, including diabetes, pain, cognition, and chronic inflammatory and immunologic diseases. However, as the vast majority of current approaches to kinase inhibition target the highly conserved ATP-binding site, the use of kinase inhibitors in treating nononcology diseases may require great selectivity for the target kinase. As protein kinases are signal transducers that are involved in binding to a variety of other proteins, targeting alternative, less conserved sites on the protein may provide an avenue for greater selectivity. Here we report an affinity-based, high-throughput screening technique that allows nonbiased interrogation of small molecule libraries for binding to all exposed sites on a protein surface. This approach was used to screen both the c-Jun N-terminal protein kinase Jnk-1 (involved in insulin signaling) and p38{alpha} (involved in the formation of TNF{alpha} and other cytokines). In addition to canonical ATP-site ligands, compounds were identified that bind to novel allosteric sites. The nature, biological relevance, and mode of binding of these ligands were extensively characterized using two-dimensional {sup 1}H/{sup 13}C NMR spectroscopy, protein X-ray crystallography, surface plasmon resonance, and direct enzymatic activity and activation cascade assays. Jnk-1 and p38{alpha} both belong to the MAP kinase family, and the allosteric ligands for both targets bind similarly on a ledge of the protein surface exposed by the MAP insertion present in the CMGC family of protein kinases and distant from the active site. Medicinal chemistry studies resulted in an improved Jnk-1 ligand able to increase adiponectin secretion in human adipocytes and increase insulin-induced protein kinase PKB phosphorylation in human hepatocytes, in

  4. Unveiling the water-associated conformational mobility in the active site of ascorbate peroxidase.

    Science.gov (United States)

    Chao, Wei-Chih; Lin, Li-Ju; Lu, Jyh-Feng; Wang, Jinn-Shyan; Lin, Tzu-Chieh; Chen, Yi-Han; Chen, Yi-Ting; Yang, Hsiao-Ching; Chou, Pi-Tai

    2018-03-01

    We carried out comprehensive spectroscopic studies of wild type and mutants of ascorbate peroxidase (APX) to gain understanding of the conformational mobility of the active site. In this approach, three unnatural tryptophans were applied to replace the distal tryptophan (W41) in an aim to probe polarity/water environment near the edge of the heme-containing active site. 7-azatryptophan ((7-aza)Trp) is sensitive to environment polarity, while 2,7-azatryptophan ((2,7-aza)Trp) and 2,6-diazatryptophan ((2,6-aza)Trp) undergo excited-state water-catalyzed double and triple proton transfer, respectively, and are sensitive to the water network. The combination of their absorption, emission bands and the associated relaxation dynamics of these fluorescence probes, together with the Soret-band difference absorption and resonance Raman spectroscopy, lead us to unveil the water associated conformational mobility in the active site of APX. The results are suggestive of the existence of equilibrium between two different environments surrounding W41 in APX, i.e., the water-rich and water-scant forms with distinct fluorescence relaxation. Our results thus demonstrate for the first time the power of integrating multiple sensors (7-aza)Trp, (2,7-aza)Trp and (2,6-aza)Trp in probing the water environment of a specifically targeted Trp in proteins. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. High throughput protease profiling comprehensively defines active site specificity for thrombin and ADAMTS13.

    Science.gov (United States)

    Kretz, Colin A; Tomberg, Kärt; Van Esbroeck, Alexander; Yee, Andrew; Ginsburg, David

    2018-02-12

    We have combined random 6 amino acid substrate phage display with high throughput sequencing to comprehensively define the active site specificity of the serine protease thrombin and the metalloprotease ADAMTS13. The substrate motif for thrombin was determined by >6,700 cleaved peptides, and was highly concordant with previous studies. In contrast, ADAMTS13 cleaved only 96 peptides (out of >10 7 sequences), with no apparent consensus motif. However, when the hexapeptide library was substituted into the P3-P3' interval of VWF73, an exosite-engaging substrate of ADAMTS13, 1670 unique peptides were cleaved. ADAMTS13 exhibited a general preference for aliphatic amino acids throughout the P3-P3' interval, except at P2 where Arg was tolerated. The cleaved peptides assembled into a motif dominated by P3 Leu, and bulky aliphatic residues at P1 and P1'. Overall, the P3-P2' amino acid sequence of von Willebrand Factor appears optimally evolved for ADAMTS13 recognition. These data confirm the critical role of exosite engagement for substrates to gain access to the active site of ADAMTS13, and define the substrate recognition motif for ADAMTS13. Combining substrate phage display with high throughput sequencing is a powerful approach for comprehensively defining the active site specificity of proteases.

  6. Results of chemical analyses of soil, shale, and soil/shale extract from the Mancos Shale formation in the Gunnison Gorge National Conservation Area, southwestern Colorado, and at Hanksville, Utah

    Science.gov (United States)

    Tuttle, Michele L.W.; Fahy, Juli; Grauch, Richard I.; Ball, Bridget A.; Chong, Geneva W.; Elliott, John G.; Kosovich, John J.; Livo, Keith E.; Stillings, Lisa L.

    2007-01-01

    Results of chemical and some isotopic analyses of soil, shale, and water extracts collected from the surface, trenches, and pits in the Mancos Shale are presented in this report. Most data are for sites on the Gunnison Gorge National Conservation Area (GGNCA) in southwestern Colorado. For comparison, data from a few sites from the Mancos landscape near Hanksville, Utah, are included. Twelve trenches were dug on the GGNCA from which 258 samples for whole-rock (total) analyses and 187 samples for saturation paste extracts were collected. Sixteen of the extract samples were duplicated and subjected to a 1:5 water extraction for comparison. A regional soil survey across the Mancos landscape on the GGNCA generated 253 samples for whole-rock analyses and saturation paste extractions. Seventeen gypsum samples were collected on the GGNCA for sulfur and oxygen isotopic analysis. Sixteen samples were collected from shallow pits in the Mancos Shale near Hanksville, Utah.

  7. Days of dismantling activities of installations and rehabilitation of contaminated sites in France

    International Nuclear Information System (INIS)

    2008-01-01

    The objective of these days, organized by the section environment of the French society of radiation protection, is to present a panorama of the activities of nuclear installations dismantling and contaminated sites rehabilitation in France, by leaning in the same time on practical cases and by stating the French rule and the national and international recommendations on the subject. These days have also for object to approach the stakes associated with the sectors of waste management and the materials generated by these activities and in a more general way, the stakes to come for the different actors of the dismantling and the rehabilitation. (N.C.)

  8. Measurement of human tissue-type plasminogen activator by a two-site immunoradiometric assay

    International Nuclear Information System (INIS)

    Rijken, D.C.; Juhan-Vague, I.; De Cock, F.; Collen, D.

    1983-01-01

    A two-site immunoradiometric assay for human extrinsic (tissue-type) plasminogen activator was developed by using rabbit antibodies raised against plasminogen activator purified from human melanoma cell culture fluid. Samples of 100 μl containing 1 to 100 ng/ml plasminogen activator were incubated in the wells of polyvinyl chloride microtiter plates coated with antibody. The amount of bound extrinsic plasminogen activator was quantitated by the subsequent binding of 125 I-labeled affinospecific antibody. The mean level of plasma samples taken at rest was 6.6 +/- 2.9 ng/ml (n = 54). This level increased approximately threefold by exhaustive physical exercise, venous occlusion, or infusion of DDAVP. Extrinsic plasminogen activator in plasma is composed of a fibrin-adsorbable and active component (1.9 +/- 1.1 ng/ml, n = 54, in resting conditions) and an inactive component that does not bind to a fibrin clot (probably extrinsic plasminogen activator-proteinase inhibitor complexes). The fibrin-adsorbable fraction increased approximately fivefold to eightfold after physical exercise, venous occlusion, or DDAVP injections. Potential applications of the immunoradiometric assay are illustrated by the measurement of extrinsic plasminogen activator in different tissue extracts, body fluids, and cell culture fluids and in oocyte translation products after injection with mRNA for plasminogen activator

  9. Altering the spectrum of immunoglobulin V gene somatic hypermutation by modifying the active site of AID.

    Science.gov (United States)

    Wang, Meng; Rada, Cristina; Neuberger, Michael S

    2010-01-18

    High-affinity antibodies are generated by somatic hypermutation with nucleotide substitutions introduced into the IgV in a semirandom fashion, but with intrinsic mutational hotspots strategically located to optimize antibody affinity maturation. The process is dependent on activation-induced deaminase (AID), an enzyme that can deaminate deoxycytidine in DNA in vitro, where its activity is sensitive to the identity of the 5'-flanking nucleotide. As a critical test of whether such DNA deamination activity underpins antibody diversification and to gain insight into the extent to which the antibody mutation spectrum is dependent on the intrinsic substrate specificity of AID, we investigated whether it is possible to change the IgV mutation spectrum by altering AID's active site such that it prefers a pyrimidine (rather than a purine) flanking the targeted deoxycytidine. Consistent with the DNA deamination mechanism, B cells expressing the modified AID proteins yield altered IgV mutation spectra (exhibiting a purine-->pyrimidine shift in flanking nucleotide preference) and altered hotspots. However, AID-catalyzed deamination of IgV targets in vitro does not yield the same degree of hotspot dominance to that observed in vivo, indicating the importance of features beyond AID's active site and DNA local sequence environment in determining in vivo hotspot dominance.

  10. Flexibility Matters: Cooperative Active Sites in Covalent Organic Framework and Threaded Ionic Polymer.

    Science.gov (United States)

    Sun, Qi; Aguila, Briana; Perman, Jason; Nguyen, Nicholas; Ma, Shengqian

    2016-12-07

    The combination of two or more reactive centers working in concert on a substrate to facilitate the reaction is now considered state of the art in catalysis, yet there still remains a tremendous challenge. Few heterogeneous systems of this sort have been exploited, as the active sites spatially separated within the rigid framework are usually difficult to cooperate. It is now shown that this roadblock can be surpassed. The underlying principle of the strategy presented here is the integration of catalytic components with excellent flexibility and porous heterogeneous catalysts, as demonstrated by the placement of linear ionic polymers in close proximity to surface Lewis acid active sites anchored on the walls of a covalent organic framework (COF). Using the cycloaddition of the epoxides and CO 2 as a model reaction, dramatic activity improvements have been achieved for the composite catalysts in relation to the individual catalytic component. Furthermore, they also clearly outperform the benchmark catalytic systems formed by the combination of the molecular organocatalysts and heterogeneous Lewis acid catalysts, while affording additional recyclability. The extraordinary flexibility and enriched concentration of the catalytically active moieties on linear polymers facilitate the concerted catalysis, thus leading to superior catalytic performance. This work therefore uncovers an entirely new strategy for designing bifunctional catalysts with double-activation behavior and opens a new avenue in the design of multicapable systems that mimic biocatalysis.

  11. Engineered disulfide bonds increase active-site local stability and reduce catalytic activity of a cold-adapted alkaline phosphatase.

    Science.gov (United States)

    Asgeirsson, Bjarni; Adalbjörnsson, Björn Vidar; Gylfason, Gudjón Andri

    2007-06-01

    Alkaline phosphatase is an extracellular enzyme that is membrane-bound in eukaryotes but resides in the periplasmic space of bacteria. It normally carries four cysteine residues that form two disulfide bonds, for instance in the APs of Escherichia coli and vertebrates. An AP variant from a Vibrio sp. has only one cysteine residue. This cysteine is second next to the nucleophilic serine in the active site. We have individually modified seven residues to cysteine that are on two loops predicted to be within a 5 A radius. Four of them formed a disulfide bond to the endogenous cysteine. Thermal stability was monitored by circular dichroism and activity measurements. Global stability was similar to the wild-type enzyme. However, a significant increase in heat-stability was observed for the disulfide-containing variants using activity as a measure, together with a large reduction in catalytic rates (k(cat)) and a general decrease in Km values. The results suggest that a high degree of mobility near the active site and in the helix carrying the endogenous cysteine is essential for full catalytic efficiency in the cold-adapted AP.

  12. Simulation analysis of within-day flow fluctuation effects on trout below flaming Gorge Dam.

    Energy Technology Data Exchange (ETDEWEB)

    Railsback, S. F.; Hayse, J. W.; LaGory, K. E.; Environmental Science Division; EPRI

    2006-01-01

    In addition to being renewable, hydropower has the advantage of allowing rapid load-following, in that the generation rate can easily be varied within a day to match the demand for power. However, the flow fluctuations that result from load-following can be controversial, in part because they may affect downstream fish populations. At Flaming Gorge Dam, located on the Green River in northeastern Utah, concern has been raised about whether flow fluctuations caused by the dam disrupt feeding at a tailwater trout fishery, as fish move in response to flow changes and as the flow changes alter the amount or timing of the invertebrate drift that trout feed on. Western Area Power Administration (Western), which controls power production on submonthly time scales, has made several operational changes to address concerns about flow fluctuation effects on fisheries. These changes include reducing the number of daily flow peaks from two to one and operating within a restricted range of flows. These changes significantly reduce the value of the power produced at Flaming Gorge Dam and put higher load-following pressure on other power plants. Consequently, Western has great interest in understanding what benefits these restrictions provide to the fishery and whether adjusting the restrictions could provide a better tradeoff between power and non-power concerns. Directly evaluating the effects of flow fluctuations on fish populations is unfortunately difficult. Effects are expected to be relatively small, so tightly controlled experiments with large sample sizes and long study durations would be needed to evaluate them. Such experiments would be extremely expensive and would be subject to the confounding effects of uncontrollable variations in factors such as runoff and weather. Computer simulation using individual-based models (IBMs) is an alternative study approach for ecological problems that are not amenable to analysis using field studies alone. An IBM simulates how a

  13. Design of anti-slide piles for slope stabilization in Wanzhou city, Three Gorges Area, China

    Science.gov (United States)

    Zhou, Chunmei; van Westen, Cees

    2013-04-01

    This study is related to the design of anti-slide piles for several landslides in Wanzhou city located in the Three Gorges area. Due to the construction of the Three Gorges Reservoir the hydro-geological conditions in this area have deteriorated significantly, leading to larger instability problems. China has invested a lot of money in slope stabilization measures for the treatment of landslides in the Three Gorges area. One of the methods for the stabilization of large landslides is the design of anti-sliding piles. This paper focuses on extensive slope stability analysis and modeling of the mechanical behavior of the landslide masses, and the parameters required for designing the number, size and dimensions of reinforced concrete stabilization piles. The study focuses on determining the rock parameters, anchor depth, and the pile and soil interaction coefficient. The study aims to provide guidelines for anti-slide pile stabilization works for landslides in the Wanzhou area. The research work contains a number of aspects. First a study is carried out on the distribution of pressures expected on the piles, using two different methods that take into account the expected pore water pressure and seismic acceleration. For the Ercengyan landslide , the Limit Equilibrium Method and Strength Reduction Method of FEM are compared through the results of the landslide pressure distributions on the piles and stress fields in the piles. The second component is the study of the required anchor depth of antislide piles, which is carried out using a statistical analysis with data from 20 landslides that have been controlled with anti-sliding piles. The rock characteristics of the anchor locations were obtained using laboratory tests, and a classification of rock mass quality is made for the anchors of antislide piles. The relationship between the critical anchor height and the angle of the landslide slip surface is determined. Two different methods are presented for the length

  14. Orthogonal electrode catheter array for mapping of endocardial focal site of ventricular activation

    Energy Technology Data Exchange (ETDEWEB)

    Desai, J.M.; Nyo, H.; Vera, Z.; Seibert, J.A.; Vogelsang, P.J. (Division of Cardiovascular Medicine, University of California, School of Medicine, Davis (USA))

    1991-04-01

    Precise location of the endocardial site of origin of ventricular tachycardia may facilitate surgical and catheter ablation of this arrhythmia. The endocardial catheter mapping technique can locate the site of ventricular tachycardia within 4-8 cm2 of the earliest site recorded by the catheter. This report describes an orthogonal electrode catheter array (OECA) for mapping and radiofrequency ablation (RFA) of endocardial focal site of origin of a plunge electrode paced model of ventricular activation in dogs. The OECA is an 8 F five pole catheter with four peripheral electrodes and one central electrode (total surface area 0.8 cm{sup 2}). In eight mongrel dogs, mapping was performed by arbitrarily dividing the left ventricle (LV) into four segments. Each segment was mapped with OECA to find the earliest segment. Bipolar and unipolar electrograms were obtained. The plunge electrode (not visible on fluoroscopy) site was identified by the earliest wave front arrival times of -30 msec or earlier at two or more electrodes (unipolar electrograms) with reference to the earliest recorded surface ECG (I, AVF, and V1). Validation of the proximity of the five electrodes of the OECA to the plunge electrode was performed by digital radiography and RFA. Pathological examination was performed to document the proximity of the OECA to the plunge electrode and also for the width, depth, and microscopic changes of the ablation. To find the segment with the earliest LV activation a total of 10 {plus minus} 3 (mean {plus minus} SD) positions were mapped. Mean arrival times at the two earlier electrodes were -39 {plus minus} 4 msec and -35 {plus minus} 3 msec. Digital radiography showed the plunge electrode to be within the area covered by all five electrodes in all eight dogs. The plunge electrode was within 1 cm2 area of the region of RFA in all eight dogs.

  15. Retro-binding thrombin active site inhibitors: identification of an orally active inhibitor of thrombin catalytic activity.

    Science.gov (United States)

    Iwanowicz, Edwin J; Kimball, S David; Lin, James; Lau, Wan; Han, W-C; Wang, Tammy C; Roberts, Daniel G M; Schumacher, W A; Ogletree, Martin L; Seiler, Steven M

    2002-11-04

    A series of retro-binding inhibitors of human alpha-thrombin was prepared to elucidate structure-activity relationships (SAR) and optimize in vivo performance. Compounds 9 and 11, orally active inhibitors of thrombin catalytic activity, were identified to be efficacious in a thrombin-induced lethality model in mice.

  16. Probing the electrostatics of active site microenvironments along the catalytic cycle for Escherichia coli dihydrofolate reductase.

    Science.gov (United States)

    Liu, C Tony; Layfield, Joshua P; Stewart, Robert J; French, Jarrod B; Hanoian, Philip; Asbury, John B; Hammes-Schiffer, Sharon; Benkovic, Stephen J

    2014-07-23

    Electrostatic interactions play an important role in enzyme catalysis by guiding ligand binding and facilitating chemical reactions. These electrostatic interactions are modulated by conformational changes occurring over the catalytic cycle. Herein, the changes in active site electrostatic microenvironments are examined for all enzyme complexes along the catalytic cycle of Escherichia coli dihydrofolate reductase (ecDHFR) by incorporation of thiocyanate probes at two site-specific locations in the active site. The electrostatics and degree of hydration of the microenvironments surrounding the probes are investigated with spectroscopic techniques and mixed quantum mechanical/molecular mechanical (QM/MM) calculations. Changes in the electrostatic microenvironments along the catalytic environment lead to different nitrile (CN) vibrational stretching frequencies and (13)C NMR chemical shifts. These environmental changes arise from protein conformational rearrangements during catalysis. The QM/MM calculations reproduce the experimentally measured vibrational frequency shifts of the thiocyanate probes across the catalyzed hydride transfer step, which spans the closed and occluded conformations of the enzyme. Analysis of the molecular dynamics trajectories provides insight into the conformational changes occurring between these two states and the resulting changes in classical electrostatics and specific hydrogen-bonding interactions. The electric fields along the CN axes of the probes are decomposed into contributions from specific residues, ligands, and solvent molecules that make up the microenvironments around the probes. Moreover, calculation of the electric field along the hydride donor-acceptor axis, along with decomposition of this field into specific contributions, indicates that the cofactor and substrate, as well as the enzyme, impose a substantial electric field that facilitates hydride transfer. Overall, experimental and theoretical data provide evidence for

  17. Modeling emissions and dispersion of contaminants from cleanup activities at a mixed waste site to estimate air impacts and risks

    International Nuclear Information System (INIS)

    Chang, Y.S.; Menlove, S.

    1993-09-01

    The transport and dispersion of contaminants via the air pathway is a major concern during cleanup of contaminated sites. Impacts to air quality and human health during cleanup were evaluated for the Weldon Spring site by using site-specific information for source areas, activities, and receptor locations. In order to ensure protection of human health and the environment, results are being used to focus on those cleanup activities for which release controls should be emphasized

  18. Multi-Modal Active Perception for Autonomously Selecting Landing Sites on Icy Moons

    Science.gov (United States)

    Arora, A.; Furlong, P. M.; Wong, U.; Fong, T.; Sukkarieh, S.

    2017-01-01

    Selecting suitable landing sites is fundamental to achieving many mission objectives in planetary robotic lander missions. However, due to sensing limitations, landing sites which are both safe and scientifically valuable often cannot be determined reliably from orbit, particularly, in icy moon missions where orbital sensing data is noisy and incomplete. This paper presents an active perception approach to Entry Descent and Landing (EDL) which enables the lander to autonomously plan informative descent trajectories, acquire high quality sensing data during descent and exploit this additional information to select higher utility landing sites. Our approach consists of two components: probabilistic modeling of landing site features and approximate trajectory planning using a sampling based planner. The proposed framework allows the lander to plan long horizons paths and remain robust to noisy data. Results in simulated environments show large performance improvements over alternative approaches and show promise that our approach has strong potential to improve science return of not only icy moon missions but EDL systems in general.

  19. Active prospective surveillance study with post-discharge surveillance of surgical site infections in Cambodia

    Directory of Open Access Journals (Sweden)

    José Guerra

    2015-05-01

    Full Text Available Summary: Barriers to the implementation of the Centers for Disease Control and Prevention (CDC guidelines for surgical site infection (SSI surveillance have been described in resource-limited settings. This study aimed to estimate the SSI incidence rate in a Cambodian hospital and to compare different modalities of SSI surveillance. We performed an active prospective study with post-discharge surveillance. During the hospital stay, trained surveyors collected the CDC criteria to identify SSI by direct examination of the surgical site. After discharge, a card was given to each included patient to be presented to all practitioners examining the surgical site. Among 167 patients, direct examination of the surgical site identified a cumulative incidence rate of 14 infections per 100 patients. An independent review of medical charts presented a sensitivity of 16%. The sensitivity of the purulent drainage criterion to detect SSIs was 83%. After hospital discharge, 87% of the patients provided follow-up data, and nine purulent drainages were reported by a practitioner (cumulative incidence rate: 20%. Overall, the incidence rate was dependent on the surveillance modalities. The review of medical charts to identify SSIs during hospitalization was not effective; the use of a follow-up card with phone calls for post-discharge surveillance was effective. Keywords: Surgical wound infection, Cambodia, Infection control, Developing countries, Follow-up studies, Feasibility studies

  20. Cernavoda Unit 2: - BOP 3D model proposal for a possible organization of site activities

    International Nuclear Information System (INIS)

    Ghiesura, G.; Scarsin, Sioli; Orlandi, S.

    1999-01-01

    The scope of this activity is to define characteristics and advantages of the 3D model of Cernavoda BOP to this set up at site for engineering and construction activities. This model will provide a modern and proven tool able to strongly support the site activities with particular regard to the following: 1. engineering activities, - plant arrangement 'double check' for resolution of clashing; - easy management of future design changes; - real time plant configuration updating as soon as any design modification is approved and integrated in the model; - preparation of high quality documentation for procurement, construction and commissioning; - prompt availability of the as built configuration of the plant as soon as the last modification is frozen; 2. material procurement activities, - definition of the priorities in the construction material procurement according to the construction planning by area; - inventory list of equipment, pipes, fittings, valves, cable trays and ventilation ducts to be installed in each construction area; 3. construction activities, - definition of construction sequences, with particular reference in the congested areas, for piping cable trays (electrical and C-and-I) and ventilations ducts; - definition of piping spools by construction contractors; - follow-up of the activities in each area (i.e. construction, painting, insulation, flushing, pressure testing, etc); 4. turn-over and commissioning, - check of the progress. The success of this approach is based on the following: i) proper management of the remote workstations providing easy and reliable access to the model; ii) subdivision of the Integrated Building in construction areas, whose detail design may be allotted to Romanian organizations with multidisciplinary tasks; iii) integration in the model of the remote developed engineering in order to validate the details of the design. (authors)

  1. Determination of the Bridging Ligand in the Active Site of Tyrosinase

    Directory of Open Access Journals (Sweden)

    Congming Zou

    2017-10-01

    Full Text Available Tyrosinase is a type-3 copper enzyme that is widely distributed in plants, fungi, insects, and mammals. Developing high potent inhibitors against tyrosinase is of great interest in diverse fields including tobacco curing, food processing, bio-insecticides development, cosmetic development, and human healthcare-related research. In the crystal structure of Agaricus bisporus mushroom tyrosinase, there is an oxygen atom bridging the two copper ions in the active site. It is unclear whether the identity of this bridging oxygen is a water molecule or a hydroxide anion. In the present study, we theoretically determine the identity of this critical bridging oxygen by performing first-principles hybrid quantum mechanics/molecular mechanics/Poisson-Boltzmann-surface area (QM/MM-PBSA calculations along with a thermodynamic cycle that aim to improve the accuracy. Our results show that the binding with water molecule is energy favored and the QM/MM-optimized structure is very close to the crystal structure, whereas the binding with hydroxide anions causes the increase of energy and significant structural changes of the active site, indicating that the identity of the bridging oxygen must be a water molecule rather than a hydroxide anion. The different binding behavior between water and hydroxide anions may explain why molecules with a carboxyl group or too many negative charges have lower inhibitory activity. In light of this, the design of high potent active inhibitors against tyrosinase should satisfy both the affinity to the copper ions and the charge neutrality of the entire molecule.

  2. Effect of particle surface area on ice active site densities retrieved from droplet freezing spectra

    Directory of Open Access Journals (Sweden)

    H. Beydoun

    2016-10-01

    Full Text Available Heterogeneous ice nucleation remains one of the outstanding problems in cloud physics and atmospheric science. Experimental challenges in properly simulating particle-induced freezing processes under atmospherically relevant conditions have largely contributed to the absence of a well-established parameterization of immersion freezing properties. Here, we formulate an ice active, surface-site-based stochastic model of heterogeneous freezing with the unique feature of invoking a continuum assumption on the ice nucleating activity (contact angle of an aerosol particle's surface that requires no assumptions about the size or number of active sites. The result is a particle-specific property g that defines a distribution of local ice nucleation rates. Upon integration, this yields a full freezing probability function for an ice nucleating particle. Current cold plate droplet freezing measurements provide a valuable and inexpensive resource for studying the freezing properties of many atmospheric aerosol systems. We apply our g framework to explain the observed dependence of the freezing temperature of droplets in a cold plate on the concentration of the particle species investigated. Normalizing to the total particle mass or surface area present to derive the commonly used ice nuclei active surface (INAS density (ns often cannot account for the effects of particle concentration, yet concentration is typically varied to span a wider measurable freezing temperature range. A method based on determining what is denoted an ice nucleating species' specific critical surface area is presented and explains the concentration dependence as a result of increasing the variability in ice nucleating active sites between droplets. By applying this method to experimental droplet freezing data from four different systems, we demonstrate its ability to interpret immersion freezing temperature spectra of droplets containing variable particle concentrations. It is shown

  3. Summary report of Hanford Site well remediation and decommissioning activities for fiscal year 1994

    International Nuclear Information System (INIS)

    Reynolds, K.D.

    1994-01-01

    Remediation and decommissioning of Hanford Site wells has become an integral part of Hanford Site Environmental Restoration (ER) and Resource Conservation and Recovery Act of 1976 (RCRA) groundwater monitoring programs. A well remediation and decommissioning program was funded and implemented in fiscal year (FY) 1993 under the RCRA and Operational Monitoring (ROM) Program. Funding for this work increased in FY 1994. In FY 1994 well decommissioning activities conducted for the ROM program were centered around the 200 West Area; activities for the ER program were centered in the Fitzner/Eberhart Arid Land Ecology (ALE) (Reserve) unit and the Wahluke Slope (North Slope) area. A total of 116 wells and test borings were decommissioned between the two programs during FY 1994. Additionally, five wells were identified as in need of remediation and were successfully brought into compliance with regulatory requirements. As Hanford Site restoration and remediation efforts increase in scope, the well decommissioning program will remain dynamic. The program will aggressively seek to fulfill the needs of the various environmental cleanup and groundwater/vadose monitoring programs. Wells that do not meet regulatory requirements for preservation will continually be identified and remediated or decommissioned accordingly

  4. Integrin activation dynamics between the RGD-binding site and the headpiece hinge.

    Science.gov (United States)

    Puklin-Faucher, Eileen; Vogel, Viola

    2009-12-25

    Integrins form mechanical links between the extracellular matrix and the cytoskeleton. Although integrin activation is known to be regulated by an allosteric conformational change, which can be induced from the extracellular or intracellular end of the molecule, little is known regarding the sequence of structural events by which signals propagate between distant sites. Here, we reveal with molecular dynamics simulations of the FnIII(10)-bound alpha(V)beta(3) integrin headpiece how the binding pocket and interdomain betaA/hybrid domain hinge on the distal end of the betaA domain are allosterically linked via a hydrophobic T-junction between the middle of the alpha1 helix and top of the alpha7 helix. The key results of this study are: 1) that this T-junction is induced by ligand binding and hinge opening, and thus displays bidirectionality; 2) that formation of this junction can be accelerated by ligand-mediated force; and 3) how formation of this junction is inhibited by Ca(2+) in place of Mg(2+) at the site adjacent to the metal ion-dependent adhesion site ("ADMIDAS"). Together with recent experimental evidence that integrin complexes can form catch bonds (i.e. become strengthened under force), as well as earlier evidence that Ca(2+) at the ADMIDAS results in lower binding affinity, these simulations provide a common structural model for the dynamic process by which integrins become activated.

  5. Integrin Activation Dynamics between the RGD-binding Site and the Headpiece Hinge*

    Science.gov (United States)

    Puklin-Faucher, Eileen; Vogel, Viola

    2009-01-01

    Integrins form mechanical links between the extracellular matrix and the cytoskeleton. Although integrin activation is known to be regulated by an allosteric conformational change, which can be induced from the extracellular or intracellular end of the molecule, little is known regarding the sequence of structural events by which signals propagate between distant sites. Here, we reveal with molecular dynamics simulations of the FnIII10-bound αVβ3 integrin headpiece how the binding pocket and interdomain βA/hybrid domain hinge on the distal end of the βA domain are allosterically linked via a hydrophobic T-junction between the middle of the α1 helix and top of the α7 helix. The key results of this study are: 1) that this T-junction is induced by ligand binding and hinge opening, and thus displays bidirectionality; 2) that formation of this junction can be accelerated by ligand-mediated force; and 3) how formation of this junction is inhibited by Ca2+ in place of Mg2+ at the site adjacent to the metal ion-dependent adhesion site (“ADMIDAS”). Together with recent experimental evidence that integrin complexes can form catch bonds (i.e. become strengthened under force), as well as earlier evidence that Ca2+ at the ADMIDAS results in lower binding affinity, these simulations provide a common structural model for the dynamic process by which integrins become activated. PMID:19762919

  6. Stress-induced enhancement of leukocyte trafficking into sites of surgery or immune activation

    Science.gov (United States)

    Viswanathan, Kavitha; Dhabhar, Firdaus S.

    2005-04-01

    Effective immunoprotection requires rapid recruitment of leukocytes into sites of surgery, wounding, infection, or vaccination. In contrast to immunosuppressive chronic stressors, short-term acute stressors have immunoenhancing effects. Here, we quantify leukocyte infiltration within a surgical sponge to elucidate the kinetics, magnitude, subpopulation, and chemoattractant specificity of an acute stress-induced increase in leukocyte trafficking to a site of immune activation. Mice acutely stressed before sponge implantation showed 200-300% higher neutrophil, macrophage, natural killer cell, and T cell infiltration than did nonstressed animals. We also quantified the effects of acute stress on lymphotactin- (LTN; a predominantly lymphocyte-specific chemokine), and TNF-- (a proinflammatory cytokine) stimulated leukocyte infiltration. An additional stress-induced increase in infiltration was observed for neutrophils, in response to TNF-, macrophages, in response to TNF- and LTN, and natural killer cells and T cells in response to LTN. These results show that acute stress initially increases trafficking of all major leukocyte subpopulations to a site of immune activation. Tissue damage-, antigen-, or pathogen-driven chemoattractants subsequently determine which subpopulations are recruited more vigorously. Such stress-induced increases in leukocyte trafficking may enhance immunoprotection during surgery, vaccination, or infection, but may also exacerbate immunopathology during inflammatory (cardiovascular disease or gingivitis) or autoimmune (psoriasis, arthritis, or multiple sclerosis) diseases. chemokine | psychophysiological stress | surgical sponge | wound healing | lymphotactin

  7. Assessment of pollutant biodegradation at the Yangtze three gorges dam, China

    Energy Technology Data Exchange (ETDEWEB)

    Kranzioch, Irene; Tiehm, Andreas [DVGW Technologiezentrum Wasser (TZW), Karlsruhe (Germany)

    2012-07-01

    The microbiological degradation of pollutants in the aquatic environment is affected by several key factors such as (1) the composition of the microbial community, (2) the oxidation-reduction-conditions, i.e. the availability of electron acceptors and electron donors, and (3) the mass transfer processes (e.g. biovailability of pollutants). As part of the joint Sino-German Yangtze project (www.yangtze-project.de), the Water Technology Centre (TZW) studies the microbial transformation processes with samples taken at the three gorges dam (TGD) area. In particular molecular microbiological methods such as the Polymerase Chain Reaction (PCR) are adapted and applied for a specific monitoring. The first studies focussed on the presence of dechlorinating bacteria and the degradation of halogenated substances. The experiments provide more insight into biodegradation processes and thus contribute to a better understanding of pollutant conversion in the Yangtze area. (org.)

  8. Hydraulic characteristics of the New River in the New River Gorge National River, West Virginia

    Science.gov (United States)

    Wiley, J.B.; Appel, David H.

    1989-01-01

    Traveltime, dispersion, water-surface and streambed profiles, and cross-section data were collected for use in application of flow and solute-transport models to the New River in the New River Gorge National River, West Virginia. Dye clouds subjected to increasing and decreasing flow rates (unsteady flow) showed that increasing flows shorten the cloud and decreasing flows lengthen the cloud. After the flow rate was changed and the flow was again steady, traveltime and dispersion characteristics were determined by the new rate of flow. Seven stage/streamflow relations identified the general changes of stream geometry throughout the study reach. Channel cross sections were estimated for model input. Low water and streambed profiles were developed from surveyed water surface elevations and water depths. (USGS)

  9. Key Technologies of the Hydraulic Structures of the Three Gorges Project

    Directory of Open Access Journals (Sweden)

    Xinqiang Niu

    2016-09-01

    Full Text Available To date, the Three Gorges Project is the largest hydro junction in the world. It is the key project for the integrated water resource management and development of the Changjiang River. The technology of the project, with its huge scale and comprehensive benefits, is extremely complicated, and the design difficulty is greater than that of any other hydro project in the world. A series of new design theories and methods have been proposed and applied in the design and research process. Many key technological problems regarding hydraulic structures have been overcome, such as a gravity dam with multi-layer large discharge orifices, a hydropower station of giant generating units, and a giant continual multi-step ship lock with a high water head.

  10. Research on the Placement of the Ecological Shelter Zone in the Three Gorges Reservoir Area, China

    Science.gov (United States)

    Shan, N.; Ruan, X.

    2011-12-01

    The Three Gorges Dam is built on the middle reaches of Yangtze River (Changjiang) in south-central China, which is the world's third longest river. The Three Gorges Reservoir Region (TGRR), including the entire inundated area and 19 administrative units (counties and cities) on both sides of the river, is regarded as an environmentally sensitive area. The total area of the TGRR is approximately 58000 km2. As the Three Gorges Dam fully operated, for the flood control, the water level should be kept in the range between 145 m and 175 m and the reservoir surface water area(over 1080 km2)at a water level of 175 m, with a length of 600 km. Many of cities, villages and farms have been submerged. Moreover, as a result of reservoir operation, the water-level alternation of the reservoir is opposite to the nature, which is low water level (145m) in summer and high water level (175m) in winter. The Hydro-Fluctuation Belt, with a height of 30m, will become a new pollution source due to the riparian being flooded and the submerged areas may still contain trace amounts of toxic or radioactive materials. The environmental impacts associated with large scale reservoir area often have significant negative impacts on the environment. It affects forest cover, species in the area, some endangered, water quality, increase the likelihood of earthquakes and mudslides in the area. To solve these problems, it is necessarily to construct the Ecological Shelter Zone (ESZ) along with the edge of the reservoir area. The function of the ESZ is similar to the riparian zone in reducing flood damage, improving water quality, decreasing the levels of the nonpoint source pollution load and soil erosion and rebuilding the migration routes of plant and wildlife. However, the research of the ESZ is mainly focused on rivers at field scale by now, lack of research method on reservoir at the watershed scale. As the special nature of the Three Gorges Reservoir, the construction of the ESZ in the TGRA is

  11. Synthesis and characterization of (18)F-labeled active site inhibited factor VII (ASIS).

    Science.gov (United States)

    Erlandsson, Maria; Nielsen, Carsten H; Jeppesen, Troels E; Kristensen, Jesper B; Petersen, Lars C; Madsen, Jacob; Kjaer, Andreas

    2015-05-15

    Activated factor VII blocked in the active site with Phe-Phe-Arg-chloromethyl ketone (active site inhibited factor VII (ASIS)) is a 50-kDa protein that binds with high affinity to its receptor, tissue factor (TF). TF is a transmembrane glycoprotein that plays an important role in, for example, thrombosis, metastasis, tumor growth, and tumor angiogenesis. The aim of this study was to develop an (18)F-labeled ASIS derivative to assess TF expression in tumors. Active site inhibited factor VII was labeled using N-succinimidyl-4-[(18)F]fluorobenzoate, and the [(18)F]ASIS was purified on a PD-10 desalting column. The radiochemical yield was 25 ± 6%, the radiochemical purity was >97%, and the pseudospecific radioactivity was 35 ± 9 GBq/µmol. The binding efficacy was evaluated in pull-down experiments, which monitored the binding of unlabeled ASIS and [(18)F]ASIS to TF and to a specific anti-factor VII antibody (F1A2-mAb). No significant difference in binding efficacy between [(18)F]ASIS and ASIS could be detected. Furthermore, [(18)F]ASIS was relatively stable in vitro and in vivo in mice. In conclusion, [(18)F]ASIS has for the first time been successfully synthesized as a possible positron emission tomography tracer to image TF expression levels. In vivo positron emission tomography studies to evaluate the full potential of [(18)F]ASIS are in progress. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Benzodiazepines: rat pinealocyte binding sites and augmentation of norepinephrine-stimulated N-acetyltransferase activity

    Energy Technology Data Exchange (ETDEWEB)

    Matthew, E.; Parfitt, A.G.; Sugden, D.; Engelhardt, D.L.; Zimmerman, E.A.; Klein, D.C.

    1984-02-01

    Studies of (/sup 3/H)diazepam binding to intact rat pineal cells were carried out in tissue culture preparations. The binding was saturable, reversible and proportional to the number of cells used. Scatchard analysis resulted in a linear plot (Kd . 23 nM, maximum binding sites (Bmax) . 1.56 pmol/mg of protein for cells in monolayer culture; Kd . 7 nM, Bmax . 1.3 pmol/mg of protein for cells in suspension culture). Inhibition constants (Ki) for clonazepam (500 nM), flunitrazepam (38 nM) and Ro-5-4864 (5 nM) indicated that the binding sites were probably of the ''peripheral'' type. In addition, the effects of diazepam on norepinephrine-stimulated N-acetyltransferase (NAT) activity were studied in organ culture and dissociated cell culture. Diazepam (10-50 microM) both prolonged and increased the magnitude of the norepinephrine-induced increase in NAT activity but did not affect the initial rate of rise of enzyme activity. The effect was dose-dependent and was also seen with clonazepam, flunitrazepam and Ro-5-4864, but not with Ro-15-1788. Diazepam, by itself, at these concentrations, had no effect on NAT, but enzyme activity was increased by higher concentrations (0.1-1 mM). Although a relationship between the (/sup 3/H)diazepam binding sites described here and the effect of benzodiazepines on NAT cannot be established from these studies, the data suggest that the benzodiazepines may alter melatonin levels through their action on NAT.

  13. Affinity labeling and characterization of the active site histidine of glucosephosphate isomerase

    International Nuclear Information System (INIS)

    Gibson, D.R.; Gracy, R.W.; Hartman, F.C.

    1980-01-01

    N-bromoacetylethanolamine phosphate was found to act as a specific affinity label for the active center of glucosephosphate isomerase. The inactivation process followed pseudo-first order kinetics, was irreversible, and exhibited rate saturation kinetics with minimal half-lives of inactivation of 4.5 and 6.3 min for the enzyme isolated from human placenta and rabbit muscle, respectively. The pH dependence of the inactivation process closely paralleled the pH dependence of the overall catalytic process with pK/sub a/ values at pH 6.4 and 9.0. The stoichiometry of labeling of either enzyme, as determined with N-bromo[ 14 C 2 ]acetylethanolamine phosphate, was 1 eq of the affinity label/subunit of enzyme. After acid hydrolysis and amino acid analysis of the radioactive affinity-labeled human enzyme, only radioactive 3-carboxymethyl histidine was found. In the case of the rabbit enzyme, the only radioactive derivative obtained was 1-carboxymethyl histidine. Active site tryptic peptides were isolated by solvent extraction, thin layer peptide fingerprinting, and ion exchange chromatography before and after removal of the phosphate from the active site peptide. Amino acid analysis of the labeled peptides from the two species were very similar. Using high sensitivity methods for sequence analysis, the primary structure of the active site was established as Val-Leu-His-Ala-Glu-Asn-Val-Asp (Gly,Thr,Ser) Glu-Ile (Thr-Gly-His-Lys-Glx)-Tyr-Phe. Apparent sequence homology between the catalytic center of glucosephosphate isomerase and triosephosphate isomerase suggest that the two enzymes may have evolved from a common ancestral gene

  14. Will river erosion below the Three Gorges Dam stop in the middle Yangtze?

    Science.gov (United States)

    Lai, X.; Yin, D.; Finlayson, B. L.; Wei, T.; Li, M.; Yuan, W.; Yang, S.; Dai, Z.; Gao, S.; Chen, Z.

    2017-11-01

    The environmental impact of the Three Gorges Dam has been a subject of vigorous academic, political and social debate since its inception. This includes the key issue of post-dam river channel erosion, which was predicted by the feasibility study to extend to the river mouth. In this paper we examine the geomorphic response of the channel of the middle Yangtze for 660 km downstream of the dam. Using data on channel characteristics, bed material and sediment transport, we show that in the decade following the dam closure, pre-dam seasonal erosion has been replaced by year-round erosion, a pattern most marked at the upstream end of the study area. The sediment carrying capacity of the river channel has been largely reduced below the dam. The locus of bed scour has moved progressively downstream, ceasing as the bed material became too coarse to be transported (e.g. D50: 0.29 mm pre-dam coarsened to 20 mm below the dam by 2008). About 400 km below the dam there is a reduction in channel slope that changes the sediment carrying capacity from 0.25 kg m-3 to only about 0.05 kg m-3, which is insufficient to move bed sediment. The new long-term hydro-morphological equilibrium that will be established in this section of the middle Yangtze will prevent the further incision downstream initiated by the Three Gorges Dam. The results suggest that the full extent of adverse environmental impact predicted by the pre-dam studies will not eventuate.

  15. Small mammal community succession on the beach of Dongting Lake, China after the Three Gorges Project.

    Science.gov (United States)

    Zhang, Meiwen; Wang, Yong; Li, Bo; Guo, Cong; Huang, Guoxian; Shen, Guo; Zhou, Xunjun

    2014-06-01

    Although the Three Gorges Project (TGP) may have affected the population structure and distribution of plant and animal communities, few studies have analyzed the effect of this project on small mammal communities. Therefore, the present paper compares the small mammal communities inhabiting the beaches of Dongting Lake using field investigations spanning a 20-year period, both before and after the TGP was implemented. Snap traps were used throughout the census. The results indicate that the TGP caused major changes to the structure of the small mammal community at a lake downstream of the dam. First, species abundance on the beaches increased after the project commenced. The striped field mouse (Apodemus agrarius) and the Norway rat (Rattus norvegicus), which rarely inhabited the beach before the TGP, became abundant (with marked population growth) once water was impounded by the Three Gorges Reservoir. Second, dominant species concentration indices exhibited a stepwise decline, indicating that the community structure changed from a single dominant species to a more diverse species mix after TGP implementation. Third, the regulation of water discharge release by the TGP might have caused an increase in the species diversity of the animal community on the beaches. A significant difference in diversity indices was obtained before and after the TGP operation. Similarity indices also indicate a gradual increase in species numbers. Hence, a long-term project should be established to monitor the population fluctuations of the Yangtze vole (Microtus fortis), the striped field mouse and the Norway rat to safeguard against population outbreaks (similar to the Yangtze vole outbreak in 2007), which could cause crop damage to adjacent farmland, in addition to documenting the succession process of the small mammal community inhabiting the beaches of Dongting Lake. © 2013 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley

  16. Total Nitrogen Sources of the Three Gorges Reservoir--A Spatio-Temporal Approach.

    Directory of Open Access Journals (Sweden)

    Chunping Ren

    Full Text Available Understanding the spatial and temporal variation of nutrient concentrations, loads, and their distribution from upstream tributaries is important for the management of large lakes and reservoirs. The Three Gorges Dam was built on the Yangtze River in China, the world's third longest river, and impounded the famous Three Gorges Reservoir (TGR. In this study, we analyzed total nitrogen (TN concentrations and inflow data from 2003 till 2010 for the main upstream tributaries of the TGR that contribute about 82% of the TGR's total inflow. We used time series analysis for seasonal decomposition of TN concentrations and used non-parametric statistical tests (Kruskal-Walli H, Mann-Whitney U as well as base flow segmentation to analyze significant spatial and temporal patterns of TN pollution input into the TGR. Our results show that TN concentrations had significant spatial heterogeneity across the study area (Tuo River> Yangtze River> Wu River> Min River> Jialing River>Jinsha River. Furthermore, we derived apparent seasonal changes in three out of five upstream tributaries of the TGR rivers (Kruskal-Walli H ρ = 0.009, 0.030 and 0.029 for Tuo River, Jinsha River and Min River in sequence. TN pollution from non-point sources in the upstream tributaries accounted for 68.9% of the total TN input into the TGR. Non-point source pollution of TN revealed increasing trends for 4 out of five upstream tributaries of the TGR. Land use/cover and soil type were identified as the dominant driving factors for the spatial distribution of TN. Intensifying agriculture and increasing urbanization in the upstream catchments of the TGR were the main driving factors for non-point source pollution of TN increase from 2003 till 2010. Land use and land cover management as well as chemical fertilizer use restriction were needed to overcome the threats of increasing TN pollution.

  17. Distribution, sedimentation, and bioavailability of particulate phosphorus in the mainstream of the Three Gorges Reservoir.

    Science.gov (United States)

    Tang, Xianqiang; Wu, Min; Li, Rui

    2018-09-01

    The transportation and sedimentation of particulate phosphorus (PP) in a huge reservoir such as the Three Gorges Reservoir (TGR) are closely related to the phosphorus distribution characteristics and nutritional status of the water body. In this study, the PP distribution, sedimentation, and bioavailability in the mainstream section of the TGR were investigated through a field survey, indoor simulated settlement experiment, and historical data analysis. The results indicated that PP was the major component of the total phosphorus (TP) and that the Three Gorges Dam (TGD) trapped nearly 76.25% of suspended sediment (SS) and 75.35% of PP in the TGR, even during the flood season. A decline in flow velocity promoted the deposition of PP; additionally, PP concentrations gradually dropped from 0.35 mg/L in Chongqing to 0.02 mg/L in Zigui. The static PP sedimentation process adequately fitted a pseudo-second-order kinetic equation with a maximum correlation coefficient of 0.97. Moreover, more than half of the PP sedimentation process was achieved in less than 60 min for samples collected from the upper river reaches within simulated sedimentation process. The median particle size of SS and absolute value of the water column's zeta potential were negatively and positively related to the t 12 values of PP sedimentation, respectively. Compared with the concentration and particle size of SS obtained in the pre-TGR period, the values in the mainstream section of the TGR were lower. However, the TP and Fe/Al-P contents in SS increased several times. Due to the combined effects of flow velocity reduction and SS trapping, the water transparency and bioavailability of water column phosphorus were enhanced. Thus, the risk of water bloom outburst significantly increased when the impounded water level of 175 m in the TGR became the normal state. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Mechanical Control of ATP Synthase Function: Activation Energy Difference between Tight and Loose Binding Sites

    KAUST Repository

    Beke-Somfai, Tamás

    2010-01-26

    Despite exhaustive chemical and crystal structure studies, the mechanistic details of how FoF1-ATP synthase can convert mechanical energy to chemical, producing ATP, are still not fully understood. On the basis of quantum mechanical calculations using a recent highresolution X-ray structure, we conclude that formation of the P-O bond may be achieved through a transition state (TS) with a planar PO3 - ion. Surprisingly, there is a more than 40 kJ/mol difference between barrier heights of the loose and tight binding sites of the enzyme. This indicates that even a relatively small change in active site conformation, induced by the γ-subunit rotation, may effectively block the back reaction in βTP and, thus, promote ATP. © 2009 American Chemical Society.

  19. General safety guidelines for looking for a low mass activity-long life waste storage site

    International Nuclear Information System (INIS)

    2008-01-01

    The objective of this document is to define general guidelines which must be followed during the stages of search for a site and stages of design of a storage facility for low activity-long life radioactive wastes, in order to ensure its safety after closure. After having specified the considered wastes, geological shapes, and situations, this document defines the fundamental objective and the associated criteria (protection against chemical risk, radioprotection). It presents the design aspects related to safety (safety principles and functions, waste packages, public works engineering, geological environment, storage concepts). The last part deals with the safety demonstration after site closure which includes the control of some components, the assessment of disturbances in the storage facility or due to its presence, the taking of uncertainty and sensitivity studies into account, the influence of natural events

  20. Three dimensional visualization in support of Yucca Mountain Site characterization activities

    International Nuclear Information System (INIS)

    Brickey, D.W.

    1992-01-01

    An understanding of the geologic and hydrologic environment for the proposed high-level nuclear waste repository at Yucca Mountain, NV is a critical component of site characterization activities. Conventional methods allow visualization of geologic data in only two or two and a half dimensions. Recent advances in computer workstation hardware and software now make it possible to create interactive three dimensional visualizations. Visualization software has been used to create preliminary two-, two-and-a-half-, and three-dimensional visualizations of Yucca Mountain structure and stratigraphy. The three dimensional models can also display lithologically dependent or independent parametric data. Yucca Mountain site characterization studies that will be supported by this capability include structural, lithologic, and hydrologic modeling, and repository design

  1. Molecular Active Sites in Heterogeneous Ir-La/C-Catalyzed Carbonylation of Methanol to Acetates.

    Science.gov (United States)

    Kwak, Ja Hun; Dagle, Robert; Tustin, Gerald C; Zoeller, Joseph R; Allard, Lawrence F; Wang, Yong

    2014-02-06

    We report that when Ir and La halides are deposited on carbon, exposure to CO spontaneously generates a discrete molecular heterobimetallic structure, containing an Ir-La covalent bond that acts as a highly active, selective, and stable heterogeneous catalyst for the carbonylation of methanol to produce acetic acid. This catalyst exhibits a very high productivity of ∼1.5 mol acetyl/mol Ir·s with >99% selectivity to acetyl (acetic acid and methyl acetate) without detectable loss in activity or selectivity for more than 1 month of continuous operation. The enhanced activity can be mechanistically rationalized by the presence of La within the ligand sphere of the discrete molecular Ir-La heterobimetallic structure, which acts as a Lewis acid to accelerate the normally rate-limiting CO insertion in Ir-catalyzed carbonylation. Similar approaches may provide opportunities for attaining molecular (single site) behavior similar to homogeneous catalysis on heterogeneous surfaces for other industrial applications.

  2. Structure of TSA2 reveals novel features of the active-site loop of peroxiredoxins

    DEFF Research Database (Denmark)

    Nielsen, Maja Holch; Kidmose, Rune Thomas; Jenner, Lasse Bohl

    2016-01-01

    Saccharomyces cerevisiae TSA2 belongs to the family of typical 2-Cys peroxiredoxins, a ubiquitously expressed family of redox-active enzymes that utilize a conserved peroxidatic cysteine to reduce peroxides. Typical 2-Cys peroxiredoxins have been shown to be involved in protection against oxidative...... stress and in hydrogen peroxide signalling. Furthermore, several 2-Cys peroxiredoxins, including S. cerevisiae TSA1 and TSA2, are able to switch to chaperone activity upon hyperoxidation of their peroxidatic cysteine. This makes the sensitivity to hyperoxidation of the peroxidatic cysteine a very....... This requires a local unfolding of the active site and the C-terminus. The balance between the fully folded and locally unfolded conformations is of key importance for the reactivity and sensitivity to hyperoxidation of the different peroxiredoxins. Here, the structure of a C48S mutant of TSA2 from S...

  3. Active site studies of Escherichia coli 2-keto-4-hydroxyglutarate aldolase

    International Nuclear Information System (INIS)

    Vlahos, C.J.

    1987-01-01

    The data presented delineate the complete amino acid sequence of E. coli KHG aldolase and also identify Lys-133, Glu-45, and Arg-49 as aminoacyl residues required for catalytic activity. Incubation of E. coli KHG aldolase with [ 14 C]pyruvate in the presence of NaCNBH 3 results in the incorporation of one mol of 14 C per mol of enzyme subunit. Digestion of this enzyme-adduct with trypsin, followed by purification of the peptides, allowed for the isolation of a unique radioactive peptide. Its amino acid sequence showed that the pyruvate-binding (i.e., Schiff-base forming) lysine residue is located at position 133 in the intact enzyme. E. coli KHG aldolase activity is lost when the enzyme is reacted with bromopyruvate; saturation kinetics are observed. The substrates, pyruvate and KHG, protect the enzyme from inactivation. Both facts suggest that the reagent is active-site specific. Incubation of the aldolase with [3- 14 C]bromopyruvate is associated with a concomitant loss of enzymatic activity and esterification of Glu-45; if the enzyme is denatured in the presence of excess bromopyruvate, Cys-159 and Cys-180 are also alkylated. Blocking the active-site lysine residue with pyruvate prevents Glu-45 from being esterified but does not eliminate alkylation of these two cysteine residues. Woodward's Reagent K was also found to inactivate the aldolase under conditions that are usually specific for carboxyl group modification. This aldolase is also inactivated by 1,2-cyclohexanedione. Loss of enzymatic activity occurs concomitantly with modification of one arginine residue per enzyme subunit. Treatment of the aldolase with the arginine-specific reagent, 4-(oxyacetyl)phenoxyacetic acid, followed by digestion with trypsin allowed for the isolation of a unique peptide and the identification of Arg-49 as the specific residue involved

  4. Activities of the senspol and NICOLE network concerning field investigation at contaminated sites

    Energy Technology Data Exchange (ETDEWEB)

    Ree, C.C.D.F. von [GeoDelft, AB Delft (Netherlands); Alcock, S. [Cranfield Univ. of Silsoe, Bedfordshire (United Kingdom)

    2003-07-01

    At a European level several networks can be identified aimed at developments and exchange of knowledge relevant to sustainable management of the subsurface. Based on the common interests in the field of site characterisation and monitoring the SENSPOL and NICOLE networks have established links resulting in cooperation in several project-activities. In this presentation two projects will be addressed: - Seville technicalmeeting (Aznacollar mining site). - Bridging gaps between sensor developers and (end) users in a pragmatic approach (GAPS-project). The goal of the Seville technical meeting was to apply the latest sensing technologies at a site contaminated by metal mining activities, to properly evaluate the advances and limitations in the monitoring of contaminated sites for sustainable land management and to determine further steps to commercial exploitation. Some 17 different instruments have been brought including: - Electrochemical sensors using different forms of anodic stripping voltammetry and constant current chronopotentiometry combined with several types of screen printed electrodes. - An amperometric biosensor using screen printed electrodes, which measures toxicity by inhibition effects on urease and its sensitive to Hg(II), Ag(I), Cu(I) and to a lesser extent to Pb(II), Zn(II) and Cd(II) and a selectrochemical DNA biosensor measuring overall toxicity. - A luminescent bacterial sensors for measuring the bioavailable fraction of Cd, Pb, Zn, Cu, As, and Hg, and a bioluminescent fiber optic sensor for Hg and As. - Toxicity testing instruments (Checklight 'ToxScreen Multi-Shot Test, ToxAlert {sup registered} 100 and ToxAlert {sup registered} 10) - A fieldprobe for pH, EC, TDS measurement - A lead automatic analyser AQUAMET using a ion-selective electrode. - Pulse-neutron borehole device in which interaction of neutrons with the surrounding medium can be used to monitor changes. In a two-day field session on the mining site participants were provided

  5. The active site of oxidative phosphorylation and the origin of hyperhomocysteinemia in aging and dementia.

    Science.gov (United States)

    McCully, Kilmer S

    2015-01-01

    The active site of oxidative phosphorylation and adenosine triphosphate (ATP) synthesis in mitochondria is proposed to consist of two molecules of thioretinamide bound to cobalamin, forming thioretinaco, complexed with ozone, oxygen, nicotinamide adenine dinucleotide. and inorganic phosphate, TR2CoO3O2NAD(+)H2PO4(-). Reduction of the pyridinium nitrogen of the nicotinamide group by an electron from electron transport complexes initiates polymerization of phosphate with adenosine diphosphate, yielding nicotinamide riboside and ATP bound to thioretinaco ozonide oxygen. A second electron reduces oxygen to hydroperoxyl radical, releasing ATP from the active site. A proton gradient is created within F1F0 ATPase complexes of mitochondria by reaction of protons with reduced nicotinamide riboside and with hydroperoxyl radical, yielding reduced nicotinamide riboside and hydroperoxide. The hyperhomocysteinemia of aging and dementia is attributed to decreased synthesis of adenosyl methionine by thioretinaco ozonide and ATP, causing decreased allosteric activation of cystathionine synthase and decreased allosteric inhibition of methylenetetrahydrofolate reductase and resulting in dysregulation of methionine metabolism. © 2015 by the Association of Clinical Scientists, Inc.

  6. Active Edge Sites Engineering in Nickel Cobalt Selenide Solid Solutions for Highly Efficient Hydrogen Evolution

    KAUST Repository

    Xia, Chuan

    2017-01-06

    An effective multifaceted strategy is demonstrated to increase active edge site concentration in NiCoSe solid solutions prepared by in situ selenization process of nickel cobalt precursor. The simultaneous control of surface, phase, and morphology result in as-prepared ternary solid solution with extremely high electrochemically active surface area (C = 197 mF cm), suggesting significant exposure of active sites in this ternary compound. Coupled with metallic-like electrical conductivity and lower free energy for atomic hydrogen adsorption in NiCoSe, identified by temperature-dependent conductivities and density functional theory calculations, the authors have achieved unprecedented fast hydrogen evolution kinetics, approaching that of Pt. Specifically, the NiCoSe solid solutions show a low overpotential of 65 mV at -10 mV cm, with onset potential of mere 18 mV, an impressive small Tafel slope of 35 mV dec, and a large exchange current density of 184 μA cm in acidic electrolyte. Further, it is shown that the as-prepared NiCoSe solid solution not only works very well in acidic electrolyte but also delivers exceptional hydrogen evolution reaction (HER) performance in alkaline media. The outstanding HER performance makes this solid solution a promising candidate for mass hydrogen production.

  7. Structural changes in human cytomegalovirus cytoplasmic assembly sites in the absence of UL97 kinase activity

    International Nuclear Information System (INIS)

    Azzeh, Maysa; Honigman, Alik; Taraboulos, Albert; Rouvinski, Alexander; Wolf, Dana G.

    2006-01-01

    Studies of human cytomegalovirus (HCMV) UL97 kinase deletion mutant (ΔUL97) indicated a multi-step role for this kinase in early and late phases of the viral life cycle, namely, in DNA replication, capsid maturation and nuclear egress. Here, we addressed its possible involvement in cytoplasmic steps of HCMV assembly. Using the ΔUL97 and the UL97 kinase inhibitor NGIC-I, we demonstrate that the absence of UL97 kinase activity results in a modified subcellular distribution of the viral structural protein assembly sites, from compact structures impacting upon the nucleus to diffuse perinuclear structures punctuated by large vacuoles. Infection by either wild type or ΔUL97 viruses induced a profound reorganization of wheat germ agglutinin (WGA)-positive Golgi-related structures. Importantly, the viral-induced Golgi remodeling along with the reorganization of the nuclear architecture was substantially altered in the absence of UL97 kinase activity. These findings suggest that UL97 kinase activity might contribute to organization of the viral cytoplasmic assembly sites

  8. Chemotactic Activity of Cyclophilin A in the Skin Mucus of Yellow Catfish (Pelteobagrus fulvidraco) and Its Active Site for Chemotaxis

    Science.gov (United States)

    Dawar, Farman Ullah; Tu, Jiagang; Xiong, Yang; Lan, Jiangfeng; Dong, Xing Xing; Liu, Xiaoling; Khattak, Muhammad Nasir Khan; Mei, Jie; Lin, Li

    2016-01-01

    Fish skin mucus is a dynamic barrier for invading pathogens with a variety of anti-microbial enzymes, including cyclophilin A (CypA), a multi-functional protein with peptidyl-prolyl cis/trans isomerase (PPIase) activity. Beside various other immunological functions, CypA induces leucocytes migration in vitro in teleost. In the current study, we have discovered several novel immune-relevant proteins in yellow catfish skin mucus by mass spectrometry (MS). The CypA present among them was further detected by Western blot. Moreover, the CypA present in the skin mucus displayed strong chemotactic activity for yellow catfish leucocytes. Interestingly, asparagine (like arginine in mammals) at position 69 was the critical site in yellow catfish CypA involved in leucocyte attraction. These novel efforts do not only highlight the enzymatic texture of skin mucus, but signify CypA to be targeted for anti-inflammatory therapeutics. PMID:27589721

  9. Chemotactic Activity of Cyclophilin A in the Skin Mucus of Yellow Catfish (Pelteobagrus fulvidraco and Its Active Site for Chemotaxis

    Directory of Open Access Journals (Sweden)

    Farman Ullah Dawar

    2016-08-01

    Full Text Available Fish skin mucus is a dynamic barrier for invading pathogens with a variety of anti-microbial enzymes, including cyclophilin A (CypA, a multi-functional protein with peptidyl-prolyl cis/trans isomerase (PPIase activity. Beside various other immunological functions, CypA induces leucocytes migration in vitro in teleost. In the current study, we have discovered several novel immune-relevant proteins in yellow catfish skin mucus by mass spectrometry (MS. The CypA present among them was further detected by Western blot. Moreover, the CypA present in the skin mucus displayed strong chemotactic activity for yellow catfish leucocytes. Interestingly, asparagine (like arginine in mammals at position 69 was the critical site in yellow catfish CypA involved in leucocyte attraction. These novel efforts do not only highlight the enzymatic texture of skin mucus, but signify CypA to be targeted for anti-inflammatory therapeutics.

  10. Exquisite Modulation of the Active Site of Methanocaldococcus jannaschii Adenylosuccinate Synthetase in Forward Reaction Complexes.

    Science.gov (United States)

    Karnawat, Vishakha; Mehrotra, Sonali; Balaram, Hemalatha; Puranik, Mrinalini

    2016-05-03

    In enzymes that conduct complex reactions involving several substrates and chemical transformations, the active site must reorganize at each step to complement the transition state of that chemical step. Adenylosuccinate synthetase (ADSS) utilizes a molecule each of guanosine 5'-monophosphate (GTP) and aspartate to convert inosine 5'-monophosphate (IMP) into succinyl adenosine 5'-monophosphate (sAMP) through several kinetic intermediates. Here we followed catalysis by ADSS through high-resolution vibrational spectral fingerprints of each substrate and intermediate involved in the forward reaction. Vibrational spectra show differential ligand distortion at each step of catalysis, and band positions of substrates are influenced by binding of cosubstrates. We found that the bound IMP is distorted toward its N1-deprotonated form even in the absence of any other ligands. Several specific interactions between GTP and active-site amino acid residues result in large Raman shifts and contribute substantially to intrinsic binding energy. When both IMP and GTP are simultaneously bound to ADSS, IMP is converted into an intermediate 6-phosphoryl inosine 5'-monophosphate (6-pIMP). The 6-pIMP·ADSS complex was found to be stable upon binding of the third ligand, hadacidin (HDA), an analogue of l-aspartate. We find that in the absence of HDA, 6-pIMP is quickly released from ADSS, is unstable in solution, and converts back into IMP. HDA allosterically stabilizes ADSS through local conformational rearrangements. We captured this complex and determined the spectra and structure of 6-pIMP in its enzyme-bound state. These results provide important insights into the exquisite tuning of active-site interactions with changing substrate at each kinetic step of catalysis.

  11. Generation of 3D templates of active sites of proteins with rigid prosthetic groups.

    Science.gov (United States)

    Nebel, Jean-Christophe

    2006-05-15

    With the increasing availability of protein structures, the generation of biologically meaningful 3D patterns from the simultaneous alignment of several protein structures is an exciting prospect: active sites could be better understood, protein functions and protein 3D structures could be predicted more accurately. Although patterns can already be generated at the fold and topological levels, no system produces high-resolution 3D patterns including atom and cavity positions. To address this challenge, our research focuses on generating patterns from proteins with rigid prosthetic groups. Since these groups are key elements of protein active sites, the generated 3D patterns are expected to be biologically meaningful. In this paper, we present a new approach which allows the generation of 3D patterns from proteins with rigid prosthetic groups. Using 237 protein chains representing proteins containing porphyrin rings, our method was validated by comparing 3D templates generated from homologues with the 3D structure of the proteins they model. Atom positions were predicted reliably: 93% of them had an accuracy of 1.00 A or less. Moreover, similar results were obtained regarding chemical group and cavity positions. Results also suggested our system could contribute to the validation of 3D protein models. Finally, a 3D template was generated for the active site of human cytochrome P450 CYP17, the 3D structure of which is unknown. Its analysis showed that it is biologically meaningful: our method detected the main patterns of the cytochrome P450 superfamily and the motifs linked to catalytic reactions. The 3D template also suggested the position of a residue, which could be involved in a hydrogen bond with CYP17 substrates and the shape and location of a cavity. Comparisons with independently generated 3D models comforted these hypotheses. Alignment software (Nestor3D) is available at http://www.kingston.ac.uk/~ku33185/Nestor3D.html

  12. Application of instrumental neutron activation analysis to study ceramic fragments from Damascus Castle site, Syria

    International Nuclear Information System (INIS)

    Bakraji, E.H.

    2005-01-01

    Thirty-three archaeological ceramic fragment samples from Damascus Castle archaeological site, Damascus city, Syria, were analyzed using instrumental neutron activation analysis (INAA). 36 elements were determined. These elemental concentrations have been processed using two multivariate statistical methods, cluster and factor analysis in order to determine similarities and correlation between the various samples. Factor analysis confirms that 84.8% of the ceramics samples classified by cluster analysis are correctly classified by cluster analysis. The results provided persuasive evidence that Castle pottery used at least four different clay sources. Moreover, by means of systematic local analysis it will be clear whether these sources are local or not. (author)

  13. Iron Is the Active Site in Nickel/Iron Water Oxidation Electrocatalysts

    Directory of Open Access Journals (Sweden)

    Bryan M. Hunter

    2018-04-01

    Full Text Available Efficient catalysis of the oxygen-evolution half-reaction (OER is a pivotal requirement for the development of practical solar-driven water splitting devices. Heterogeneous OER electrocatalysts containing first-row transition metal oxides and hydroxides have attracted considerable recent interest, owing in part to the high abundance and low cost of starting materials. Among the best performing OER electrocatalysts are mixed Fe/Ni layered double hydroxides (LDH. A review of the available experimental data leads to the conclusion that iron is the active site for [NiFe]-LDH-catalyzed alkaline water oxidation.

  14. Comparison of NMR and crystal structures highlights conformational isomerism in protein active sites

    International Nuclear Information System (INIS)

    Serrano, Pedro; Pedrini, Bill; Geralt, Michael; Jaudzems, Kristaps; Mohanty, Biswaranjan; Horst, Reto; Herrmann, Torsten; Elsliger, Marc-André; Wilson, Ian A.; Wüthrich, Kurt

    2010-01-01

    Tools for systematic comparisons of NMR and crystal structures developed by the JCSG were applied to two proteins with known functions: the T. maritima anti-σ factor antagonist TM1081 and the mouse γ-glutamylamine cyclotransferase A2LD1 (gi:13879369). In an attempt to exploit the complementarity of crystal and NMR data, the combined use of the two structure-determination techniques was explored for the initial steps in the challenge of searching proteins of unknown functions for putative active sites. The JCSG has recently developed a protocol for systematic comparisons of high-quality crystal and NMR structures of proteins. In this paper, the extent to which this approach can provide function-related information on the two functionally annotated proteins TM1081, a Thermotoga maritima anti-σ factor antagonist, and A2LD1 (gi:13879369), a mouse γ-glutamylamine cyclotransferase, is explored. The NMR structures of the two proteins have been determined in solution at 313 and 298 K, respectively, using the current JCSG protocol based on the software package UNIO for extensive automation. The corresponding crystal structures were solved by the JCSG at 100 K and 1.6 Å resolution and at 100 K and 1.9 Å resolution, respectively. The NMR and crystal structures of the two proteins share the same overall molecular architectures. However, the precision of the structure determination along the amino-acid sequence varies over a significantly wider range in the NMR structures than in the crystal structures. Thereby, in each of the two NMR structures about 65% of the residues have displacements below the average and in both proteins the less well ordered residues include large parts of the active sites, in addition to some highly solvent-exposed surface areas. Whereas the latter show increased disorder in the crystal and in solution, the active-site regions display increased displacements only in the NMR structures, where they undergo local conformational exchange on the

  15. How to awaken your nanomachines: Site-specific activation of focal adhesion kinases through ligand interactions

    KAUST Repository

    Walkiewicz, Katarzyna Wiktoria

    2015-06-17

    The focal adhesion kinase (FAK) and the related protein-tyrosine kinase 2-beta (Pyk2) are highly versatile multidomain scaffolds central to cell adhesion, migration, and survival. Due to their key role in cancer metastasis, understanding and inhibiting their functions are important for the development of targeted therapy. Because FAK and Pyk2 are involved in many different cellular functions, designing drugs with partial and function-specific inhibitory effects would be desirable. Here, we summarise recent progress in understanding the structural mechanism of how the tug-of-war between intramolecular and intermolecular interactions allows these protein ‘nanomachines’ to become activated in a site-specific manner.

  16. GTP plus water mimics ATP in the active site of protein kianse CK2

    DEFF Research Database (Denmark)

    Niefind, K; Pütter, M; Guerra, B

    1999-01-01

    The structures of the catalytic subunit of protein kinase CK2 from Zea mays complexed with Mg2+ and with analogs of ATP or GTP were determined to 2.2 A resolution. Unlike most other protein kinases, CK2 from various sources shows 'dual-cosubstrate specificity', that is, the ability to efficiently...... use either ATP or GTP as a cosubstrate. The structures of these complexes demonstrate that water molecules are critical to switch the active site of CK2 from an ATP- to a GTP-compatible state. An understanding of the structural basis of dual-cosubstrate specificity may help in the design of drugs...

  17. Spatial and temporal variations in non-point source losses of nitrogen and phosphorus in a small agricultural catchment in the Three Gorges Region.

    Science.gov (United States)

    Chen, Chenglong; Gao, Ming; Xie, Deti; Ni, Jiupai

    2016-04-01

    Losses of agricultural pollutants from small catchments are a major issue for water quality in the Three Gorges Region. Solutions are urgently needed. However, before pollutant losses can be controlled, information about spatial and temporal variations in pollutant losses is needed. The study was carried out in the Wangjiagou catchment, a small agricultural catchment in Fuling District, Chongqing, and the data about non-point source losses of nitrogen and phosphorus was collected here. Water samples were collected daily by an automatic water sampler at the outlets of two subcatchments from 2012 to 2014. Also, samples of surface runoff from 28 sampling sites distributed through the subcatchments were collected during 12 rainfall events in 2014. A range of water quality variables were analyzed for all samples and were used to demonstrate the variation in non-point losses of nitrogen and phosphorus over a range of temporal and spatial scales and in different types of rainfall in the catchment. Results showed that there was a significant linear correlation between the mass concentrations of total nitrogen (TN) and nitrate (NO3-N) in surface runoff and that the relationship was maintained with changes in time. Concentrations of TN and NO3-N peaked after fertilizer was applied to crops in spring and autumn; concentrations decreased rapidly after the peak values in spring but declined slowly in autumn. N and P concentrations fluctuated more and showed a greater degree of dispersion during the spring crop cultivation period than those in autumn. Concentrations of TN and NO3-N in surface runoff were significantly and positively correlated with the proportion of the area that was planted with corn and mustard tubers, but were negatively correlated with the proportion of the area taken up with rice and mulberry plantations. The average concentrations of TN and NO3-N in surface runoff reached the highest level from the sampling points at the bottom of the land used for corn

  18. Basic Study for Active Nucleation Site Density Evaluation in Subcooled Flow Boiling

    International Nuclear Information System (INIS)

    Chu, In Cheol; Song, Chul Hwa

    2008-01-01

    Numerous studies have been performed on a active nucleation site density (ANSD) due to its governing influence on a heat transfer. However, most of the studies were focused on pool boiling conditions. Kocamustafaogullari and Ishii developed an ANSD correlation from a parametric study of the existing pool boiling data. Also, they extended the correlation to a convective flow boiling condition by adopting the nucleation suppression factor of Chen's heat transfer correlation. However, the appropriateness of applying the Chen's suppression factor to an ANSD correlation was not fully validated because there was not enough experimental data on ANSD in the forced convective flow boiling. Basu et al. performed forced convective boiling experiments and proposed a correlation of ANSD which is the only correlation based on experimental data for a forced convective boiling. They concluded that the ANSD is only dependent on the static contact angle and the wall superheat, and is independent of the flow rate and the subcooling, which contradict the general acceptance of the nucleation suppression in the forced convective boiling. It seems that no reliable ANSD correlation or model is available for a forced convective boiling. In the present study, the effect of the flow velocity on the suppression of the nucleation site was examined, and the effectiveness of a Brewster reflection technique for the identification of the nucleation site was also examined

  19. Barriers and enabling factors for work-site physical activity programs: a qualitative examination.

    Science.gov (United States)

    Fletcher, Gena M; Behrens, Timothyh K; Domina, Lorie

    2008-05-01

    Work sites offer a productive setting for physical activity (PA) promoting interventions. Still, PA participation remains low. Thus, the purpose of this study was to examine the reasoning behind commonly reported barriers and enabling factors to participation in PA programs in a work-site setting. Employees from a large city government were recruited to participate in focus groups, stratified by white- and blue-collar occupations. Responses from open-ended questions about factors influencing participation in PA programs were audio recorded and transcribed verbatim. Resulting data were analyzed with open and axial coding. The sample consisted of 60 employees composing 9 focus groups. Although time was the most common barrier between both groups, white-collars workers responded that scheduling and work conflicts were the most common barrier concerning time. Blue-collar workers indicated shift work as their most common barrier. In addition, health was a significant enabling factor for both occupational categories. White-collar workers were much more concerned with appearances and were more highly motivated by weight loss and the hopefulness of quick results than were blue-collar workers. These findings are important in the understanding of PA as it relates to the reasoning behind participation in work-site programs in regard to occupational status.

  20. APE1 incision activity at abasic sites in tandem repeat sequences.

    Science.gov (United States)

    Li, Mengxia; Völker, Jens; Breslauer, Kenneth J; Wilson, David M

    2014-05-29

    Repetitive DNA sequences, such as those present in microsatellites and minisatellites, telomeres, and trinucleotide repeats (linked to fragile X syndrome, Huntington disease, etc.), account for nearly 30% of the human genome. These domains exhibit enhanced susceptibility to oxidative attack to yield base modifications, strand breaks, and abasic sites; have a propensity to adopt non-canonical DNA forms modulated by the positions of the lesions; and, when not properly processed, can contribute to genome instability that underlies aging and disease development. Knowledge on the repair efficiencies of DNA damage within such repetitive sequences is therefore crucial for understanding the impact of such domains on genomic integrity. In the present study, using strategically designed oligonucleotide substrates, we determined the ability of human apurinic/apyrimidinic endonuclease 1 (APE1) to cleave at apurinic/apyrimidinic (AP) sites in a collection of tandem DNA repeat landscapes involving telomeric and CAG/CTG repeat sequences. Our studies reveal the differential influence of domain sequence, conformation, and AP site location/relative positioning on the efficiency of APE1 binding and strand incision. Intriguingly, our data demonstrate that APE1 endonuclease efficiency correlates with the thermodynamic stability of the DNA substrate. We discuss how these results have both predictive and mechanistic consequences for understanding the success and failure of repair protein activity associated with such oxidatively sensitive, conformationally plastic/dynamic repetitive DNA domains. Published by Elsevier Ltd.

  1. Based on records of Three Gorge Telemetric Seismic Network to analyze Vibration process of micro fracture of rock landslide

    Science.gov (United States)

    WANG, Q.

    2017-12-01

    Used the finite element analysis software GeoStudio to establish vibration analysis model of Qianjiangping landslide, which locates at the Three Gorges Reservoir area. In QUAKE/W module, we chosen proper Dynamic elasticity modulus and Poisson's ratio of soil layer and rock stratum. When loading, we selected the waveform data record of Three Gorge Telemetric Seismic Network as input ground motion, which includes five rupture events recorded of Lujiashan seismic station. In dynamic simulating, we mainly focused on sliding process when the earthquake date record was applied. The simulation result shows that Qianjiangping landslide wasn't not only affected by its own static force, but also experienced the dynamic process of micro fracture-creep-slip rupture-creep-slip.it provides a new approach for the early warning feasibility of rock landslide in future research.

  2. Game-Theory Based Research on Oil-Spill Prevention and Control Modes in Three Gorges Reservoir Area

    Science.gov (United States)

    Yin, Jie; Xiong, Ting

    2018-01-01

    Aiming at solving the existing oil pollution in the Three Gorges reservoir, this paper makes research on oil-spill prevention and control mode based on game theory. Regarding the built modes and comparative indicator system, overall efficiency indicator functions are used to compare general effect, overall cost, and overall efficiency, which concludes that the mode combining government and enterprise has the highest overall efficiency in preventing and controlling ship oil spills. The suggested mode together its correspondingly designed management system, has been applied to practice for a year in Three Gorges Reservoir Area and has made evident improvements to the existing oil pollution, meanwhile proved to be quite helpful to the pollution prevention and control in the lower reaches of Yangtze River.

  3. Active site similarity between human and Plasmodium falciparum phosphodiesterases: considerations for antimalarial drug design

    Science.gov (United States)

    Howard, Brittany L.; Thompson, Philip E.; Manallack, David T.

    2011-08-01

    The similarity between Plasmodium falciparum phosphodiesterase enzymes ( PfPDEs) and their human counterparts have been examined and human PDE9A was found to be a suitable template for the construction of homology models for each of the four PfPDE isoforms. In contrast, the architecture of the active sites of each model was most similar to human PDE1. Molecular docking was able to model cyclic guanosine monophosphate (cGMP) substrate binding in each case but a docking mode supporting cyclic adenosine monophosphate (cAMP) binding could not be found. Anticipating the potential of PfPDE inhibitors as anti-malarial drugs, a range of reported PDE inhibitors including zaprinast and sildenafil were docked into the model of PfPDEα. The results were consistent with their reported biological activities, and the potential of PDE1/9 inhibitor analogues was also supported by docking.

  4. Microbial activity of trench leachates from shallow-land, low-level radioactive waste disposal sites

    International Nuclear Information System (INIS)

    Francis, A.J.; Dobbs, S.; Nine, B.J.

    1980-01-01

    Trench leachate samples collected anoxically from shallow-land, low-level radioactive waste disposal sites were analyzed for total aerobic and anaerobic populations, sulfate reducers, denitrifiers, and methanogens. Among the several aerobic and anaerobic bacteria isolated, only Bacillus sp., Pseudomonas sp., Citrobacter sp., and Clostridium sp. were identified. Mixed bacterial cultures isolated from the trench leachates were able to grow anaerobically in trench leachates, which indicates that the radionuclides and organic chemicals present were not toxic to these bacteria. Changes in concentrations of several of the organic constituents of the waste leachate samples were observed due to anaerobic microbial activity. Growth of a mixed culture of trench-water bacteria in media containing a mixture of radionuclides, 60 Co, 85 Sr, and 134 137 Cs, was not affected at total activity concentrations of 2.6 x 10 2 and 2.7 x 10 3 pCi/ml

  5. Airborne particulate concentrations and fluxes at an active uranium mill tailings site

    International Nuclear Information System (INIS)

    Sehmel, G.A.

    1978-01-01

    Direct measurements of airborne particulate concentrations and fluxes of transported mill tailing materials were measured at an active mill tailings site. Experimental measurement equipment consisted of meteorological instrumentation to automatically activate total particulate air samplers as a function of wind speed increments and direction, as well as particle cascade impactors to measure airborne respirable concentrations as a function of particle size. In addition, an inertial impaction device measured nonrespirable fluxes of airborne particles. Caclulated results are presented in terms of the airborne solid concentration in g/m 3 , the horizontal airborne mass flux in g/(m 2 -day) for total collected nonrespirable particles and the radionuclide concentrations in dpm/g as a function of particle diameter for respirable and nonrespirable particles

  6. Whole-rock U-Pb dating of the Shuijingtuo formation sedimentary rocks in the Yangtze Gorge

    International Nuclear Information System (INIS)

    Zheng, Y.F.; Huang, B.

    1990-01-01

    Black shale and enclosed limestone lenticule from Lower Cambrian Shuijingtuo Formation in the Yangtze Gorge is successfully dated by whole-rock U-Pb method. The results yield a concordant age of about 573±14 Ma, in excellent agreement with both stratigraphic and palaeontologic evidence. The whole-rock U-Pb method can provide a reliable approach for age determination of sedimentary stratum. (orig.) [de

  7. Cyanophytes on limestone rocks in the Szopczański Gorge (Pieniny Mountains – their ecomorphology and ultrastructure

    Directory of Open Access Journals (Sweden)

    Joanna Czerwik-Marcinkowska

    2011-08-01

    Full Text Available This study is devoted to the ecomorphology and ultrastructure of cyanophytes on limestone rocks collected in the Szopczański Gorge (Pieniny Mountains during the years 2006-2008. There were selected cyanophyte species for examination such as following: Nostoc microscopicum, Phormidium favosum, Leptolyngbya foveolarum, Tolypothrix distorta var. penicillatum, Pseudanabaena catenata. The ultrastructural analysis (TEM confirmed that the structure and placement of the thylakoids is genus/species specific.

  8. Functional properties of the two redox-active sites in yeast protein disulphide isomerase in vitro and in vivo

    DEFF Research Database (Denmark)

    Westphal, V; Darby, N J; Winther, Jakob R.

    1999-01-01

    to that of human PDI, both in rearrangement and oxidation reactions. However, while the a domain active site of the human enzyme is more active than the a'-site, the reverse is the case for yPDI. This prompted us to set up an assay to investigate whether the situation would be different with a native yeast......-site to be most important. We furthermore show that the apparent difference between in vivo and in vitro activities is not due to catalytic contributions from the other PDI homologues found in yeast....

  9. Effects of Flaming Gorge Dam hydropower operations on sediment transport in the Browns Park reach of the Green River, Utah and Colorado

    International Nuclear Information System (INIS)

    Williams, G.P.; Tomasko, D.; Cho, H.E.; Yin, S.C.L.

    1995-05-01

    Three methods for comparing sediment transport were applied to four proposed hydropower operational scenarios under study for Flaming Gorge Dam on the Green River in Utah. These methods were effective discharge, equilibrium potential, and cumulative sediment load with flow exceedance plots. Sediment loads transported by the Green River in the Browns Park reach were calculated with the Engelund-Hansen equation for three historical water years and four hydropower operational scenarios. A model based on the Engelund-Hansen equation was developed using site-specific information and validated by comparing predictions for a moderate water year with measured historical values. The three methods were used to assess the impacts of hydropower operational scenarios on sediment resources. The cumulative sediment load method provided the most useful information for impact evaluation. Effective discharge was not a useful tool because of the limited number of discrete flows associated with synthetic hydrographs for the hydropower operational scenarios. The equilibrium potential method was relatively insensitive to the variations in operating conditions, rendering it comparatively ineffective for impact evaluation

  10. Structural Analysis of the Active Site Geometry of N5-Carboxyaminoimidazole Ribonucleotide Synthetase from Escherichia coli

    International Nuclear Information System (INIS)

    Thoden, James B.; Holden, Hazel M.; Firestine, Steven M.

    2008-01-01

    N 5 -Carboxyaminoimidazole ribonucleotide synthetase (N 5 -CAIR synthetase) converts 5-aminoimidazole ribonucleotide (AIR), MgATP, and bicarbonate into N 5 -CAIR, MgADP, and P i . The enzyme is required for de novo purine biosynthesis in microbes yet is not found in humans suggesting that it represents an ideal and unexplored target for antimicrobial drug design. Here we report the X-ray structures of N 5 -CAIR synthetase from Escherichia coli with either MgATP or MgADP/P i bound in the active site cleft. These structures, determined to 1.6-(angstrom) resolution, provide detailed information regarding the active site geometry before and after ATP hydrolysis. In both structures, two magnesium ions are observed. Each of these is octahedrally coordinated, and the carboxylate side chain of Glu238 bridges them. For the structure of the MgADP/P i complex, crystals were grown in the presence of AIR and MgATP. No electron density was observed for AIR, and the electron density corresponding to the nucleotide clearly revealed the presence of ADP and P i rather than ATP. The bound P i shifts by approximately 3 (angstrom) relative to the γ-phosphoryl group of ATP and forms electrostatic interactions with the side chains of Arg242 and His244. Since the reaction mechanism of N 5 -CAIR synthetase is believed to proceed via a carboxyphosphate intermediate, we propose that the location of the inorganic phosphate represents the binding site for stabilization of this reactive species. Using the information derived from the two structures reported here, coupled with molecular modeling, we propose a catalytic mechanism for N 5 -CAIR synthetase.

  11. Research in Support of Remediation Activities at the Savannah River Site

    International Nuclear Information System (INIS)

    Seaman, J.C.; B.B. Looney and M.K. Harris

    2007-01-01

    The USDOE Savannah River Site (SRS), an 803-km 2 (310-mile 2 ) facility located south of Aiken, SC on the upper Atlantic Coastal Plain and bounded to the west by the Savannah River, was established in the 1950s for the production and refinement of nuclear materials. To fulfill this mission during the past 50 years SRS has operated five nuclear reactors, two large chemical separation areas, waste disposal facilities (landfills, waste ponds, waste tanks, and waste stabilization), and a large number of research and logistics support facilities. Contaminants of concern (COC) resulting from site operations include chlorinated solvents, radionuclides, metals, and metalloids, often found as complex mixtures that greatly complicate remediation efforts when compared with civilian industries. The objective of this article is to provide a description of the lithology and hydrostratigraphy of the SRS, as well as a brief history of site operations and research activities as a preface to the current special section of Vadose Zone Journal (VZJ) dedicated to SRS, focusing mainly on issues that are unique to the USDOE complex. Contributions to the special section reflect a diverse range of topics, from hydrologic tracer experiments conducted both within the vadose and saturated zones to studies specifically aimed at identifying geochemical processes controlling the migration and partitioning of specific contaminants (e.g., TCE, 137 Cs, U, and Pu) in SRS subsurface environments. Addressing the diverse environmental challenges of the SRS provides a unique opportunity to conduct both fundamental and applied research across a range of experimental scales. Hence, the SRS has been a pioneering force in several areas of environmental research and remediation, often through active interdisciplinary collaboration with researchers from other USDOE facilities, academic and federal institutions, and commercial entities

  12. Integrated experiment activity monitoring for wLCG sites based on GWT

    International Nuclear Information System (INIS)

    Feijóo, Alejandro Guinó; Espinal, Xavier

    2011-01-01

    The goal of this work is to develop a High Level Monitoring (HLM) where to merge the distributed computing activities of an LHC experiment (ATLAS). ATLAS distributed computing is organized in clouds, where the Tier-Is (primary centers) provide services to the associated Tier-2s centers (secondaries) so they are all seen as a cloud by the experiment. Computing activities and sites stability monitoring services are numerous and delocalized. It would be very useful for a cloud manager to have a single place where to aggregate available monitoring information. The idea presented in this paper is to develop a set of collectors to gather information regarding site status and performance on data distribution, data processing and Worldwide LHC Computing Grid (WLCG) tests (Service Availability Monitoring), store them in specific databases, process the results and show it in a single HLM page. Once having it, one can investigate further by interacting with the front-end, which is fed by the stats stored on databases.

  13. Active sites of two orthologous cytochromes P450 2E1: Differences revealed by spectroscopic methods

    International Nuclear Information System (INIS)

    Anzenbacherova, Eva; Hudecek, Jiri; Murgida, Daniel; Hildebrandt, Peter; Marchal, Stephane; Lange, Reinhard; Anzenbacher, Pavel

    2005-01-01

    Cytochromes P450 2E1 of human and minipig origin were examined by absorption spectroscopy under high hydrostatic pressure and by resonance Raman spectroscopy. Human enzyme tends to denature to the P420 form more easily than the minipig form; moreover, the apparent compressibility of the heme active site (as judged from a redshift of the absorption maximum with pressure) is greater than that of the minipig counterpart. Relative compactness of the minipig enzyme is also seen in the Raman spectra, where the presence of planar heme conformation was inferred from band positions characteristic of the low-spin heme with high degree of symmetry. In this respect, the CYP2E1 seems to be another example of P450 conformational heterogeneity as shown, e.g., by Davydov et al. for CYP3A4 [Biochem. Biophys. Res. Commun. 312 (2003) 121-130]. The results indicate that the flexibility of the CYP active site is likely one of its basic structural characteristics

  14. Epoxyethylglycyl peptides as inhibitors of oligosaccharyltransferase: double-labelling of the active site.

    Science.gov (United States)

    Bause, E; Wesemann, M; Bartoschek, A; Breuer, W

    1997-02-15

    Pig liver oligosaccharyltransferase (OST) is inactivated irreversibly by a hexapeptide in which threonine has been substituted by epoxyethylglycine in the Asn-Xaa-Thr glycosylation triplet. Incubation of the enzyme in the presence of Dol-PP-linked [14C]oligosaccharides and the N-3,5-dinitrobenzoylated epoxy derivative leads to the double-labelling of two subunits (48 and 66 kDa) of the oligomeric OST complex, both of which are involved in the catalytic activity. Labelling of both subunits was blocked competitively by the acceptor peptide N-benzoyl-Asu-Gly-Thr-NHCH3 and by the OST inhibitor N-benzoyl-alpha,gamma-diaminobutyric acid-Gly-Thr-NHCH3, but not by an analogue derived from the epoxy-inhibitor by replacing asparagine with glutamine. Our data clearly show that double-labelling is an active-site-directed modification, involving inhibitor glycosylation at asparagine and covalent attachment of the glycosylated inhibitor, via the epoxy group, to the enzyme. Double-labelling of OST can occur as the result of either a consecutive or a syn-catalytic reaction sequence. The latter mechanism, during the course of which OST catalyses its own 'suicide' inactivation, is more likely, as suggested by indirect experimental evidence. The syn-catalytic mechanism corresponds with our current view of the functional role of the acceptor site Thr/Ser acting as a hydrogen-bond acceptor, not a donor, during transglycosylation.

  15. The active site of hen egg-white lysozyme: flexibility and chemical bonding

    Energy Technology Data Exchange (ETDEWEB)

    Held, Jeanette, E-mail: jeanette.netzel@uni-bayreuth.de; Smaalen, Sander van [University of Bayreuth, D-95440 Bayreuth (Germany)

    2014-04-01

    Chemical bonding at the active site of lysozyme is analyzed on the basis of a multipole model employing transferable multipole parameters from a database. Large B factors at low temperatures reflect frozen-in disorder, but therefore prevent a meaningful free refinement of multipole parameters. Chemical bonding at the active site of hen egg-white lysozyme (HEWL) is analyzed on the basis of Bader’s quantum theory of atoms in molecules [QTAIM; Bader (1994 ▶), Atoms in Molecules: A Quantum Theory. Oxford University Press] applied to electron-density maps derived from a multipole model. The observation is made that the atomic displacement parameters (ADPs) of HEWL at a temperature of 100 K are larger than ADPs in crystals of small biological molecules at 298 K. This feature shows that the ADPs in the cold crystals of HEWL reflect frozen-in disorder rather than thermal vibrations of the atoms. Directly generalizing the results of multipole studies on small-molecule crystals, the important consequence for electron-density analysis of protein crystals is that multipole parameters cannot be independently varied in a meaningful way in structure refinements. Instead, a multipole model for HEWL has been developed by refinement of atomic coordinates and ADPs against the X-ray diffraction data of Wang and coworkers [Wang et al. (2007), Acta Cryst. D63, 1254–1268], while multipole parameters were fixed to the values for transferable multipole parameters from the ELMAM2 database [Domagala et al. (2012), Acta Cryst. A68, 337–351] . Static and dynamic electron densities based on this multipole model are presented. Analysis of their topological properties according to the QTAIM shows that the covalent bonds possess similar properties to the covalent bonds of small molecules. Hydrogen bonds of intermediate strength are identified for the Glu35 and Asp52 residues, which are considered to be essential parts of the active site of HEWL. Furthermore, a series of weak C

  16. Distinguishing Active Site Characteristics of Chlorite Dismutases with Their Cyanide Complexes.

    Science.gov (United States)

    Geeraerts, Zachary; Celis, Arianna I; Mayfield, Jeffery A; Lorenz, Megan; Rodgers, Kenton R; DuBois, Jennifer L; Lukat-Rodgers, Gudrun S

    2018-03-06

    O 2 -evolving chlorite dismutases (Clds) efficiently convert chlorite (ClO 2 - ) to O 2 and Cl - . Dechloromonas aromatica Cld ( DaCld) is a highly active chlorite-decomposing homopentameric enzyme, typical of Clds found in perchlorate- and chlorate-respiring bacteria. The Gram-negative, human pathogen Klebsiella pneumoniae contains a homodimeric Cld ( KpCld) that also decomposes ClO 2 - , albeit with an activity 10-fold lower and a turnover number lower than those of DaCld. The interactions between the distal pocket and heme ligand of the DaCld and KpCld active sites have been probed via kinetic, thermodynamic, and spectroscopic behaviors of their cyanide complexes for insight into active site characteristics that are deterministic for chlorite decomposition. At 4.7 × 10 -9 M, the K D for the KpCld-CN - complex is 2 orders of magnitude smaller than that of DaCld-CN - and indicates an affinity for CN - that is greater than that of most heme proteins. The difference in CN - affinity between Kp- and DaClds is predominantly due to differences in k off . The kinetics of binding of cyanide to DaCld, DaCld(R183Q), and KpCld between pH 4 and 8.5 corroborate the importance of distal Arg183 and a p K a of ∼7 in stabilizing complexes of anionic ligands, including the substrate. The Fe-C stretching and FeCN bending modes of the DaCld-CN - (ν Fe-C , 441 cm -1 ; δ FeCN , 396 cm -1 ) and KpCld-CN - (ν Fe-C , 441 cm -1 ; δ FeCN , 356 cm -1 ) complexes reveal differences in their FeCN angle, which suggest different distal pocket interactions with their bound cyanide. Conformational differences in their catalytic sites are also reported by the single ferrous KpCld carbonyl complex, which is in contrast to the two conformers observed for DaCld-CO.

  17. The active site of hen egg-white lysozyme: flexibility and chemical bonding

    International Nuclear Information System (INIS)

    Held, Jeanette; Smaalen, Sander van

    2014-01-01

    Chemical bonding at the active site of lysozyme is analyzed on the basis of a multipole model employing transferable multipole parameters from a database. Large B factors at low temperatures reflect frozen-in disorder, but therefore prevent a meaningful free refinement of multipole parameters. Chemical bonding at the active site of hen egg-white lysozyme (HEWL) is analyzed on the basis of Bader’s quantum theory of atoms in molecules [QTAIM; Bader (1994 ▶), Atoms in Molecules: A Quantum Theory. Oxford University Press] applied to electron-density maps derived from a multipole model. The observation is made that the atomic displacement parameters (ADPs) of HEWL at a temperature of 100 K are larger than ADPs in crystals of small biological molecules at 298 K. This feature shows that the ADPs in the cold crystals of HEWL reflect frozen-in disorder rather than thermal vibrations of the atoms. Directly generalizing the results of multipole studies on small-molecule crystals, the important consequence for electron-density analysis of protein crystals is that multipole parameters cannot be independently varied in a meaningful way in structure refinements. Instead, a multipole model for HEWL has been developed by refinement of atomic coordinates and ADPs against the X-ray diffraction data of Wang and coworkers [Wang et al. (2007), Acta Cryst. D63, 1254–1268], while multipole parameters were fixed to the values for transferable multipole parameters from the ELMAM2 database [Domagala et al. (2012), Acta Cryst. A68, 337–351] . Static and dynamic electron densities based on this multipole model are presented. Analysis of their topological properties according to the QTAIM shows that the covalent bonds possess similar properties to the covalent bonds of small molecules. Hydrogen bonds of intermediate strength are identified for the Glu35 and Asp52 residues, which are considered to be essential parts of the active site of HEWL. Furthermore, a series of weak C

  18. Active Site Mapping of Human Cathepsin F with Dipeptide Nitrile Inhibitors.

    Science.gov (United States)

    Schmitz, Janina; Furtmann, Norbert; Ponert, Moritz; Frizler, Maxim; Löser, Reik; Bartz, Ulrike; Bajorath, Jürgen; Gütschow, Michael

    2015-08-01

    Cleavage of the invariant chain is the key event in the trafficking pathway of major histocompatibility complex class II. Cathepsin S is the major processing enzyme of the invariant chain, but cathepsin F acts in macrophages as its functional synergist which is as potent as cathepsin S in invariant chain cleavage. Dedicated low-molecular-weight inhibitors for cathepsin F have not yet been developed. An active site mapping with 52 dipeptide nitriles, reacting as covalent-reversible inhibitors, was performed to draw structure-activity relationships for the non-primed binding region of human cathepsin F. In a stepwise process, new compounds with optimized fragment combinations were designed and synthesized. These dipeptide nitriles were evaluated on human cysteine cathepsins F, B, L, K and S. Compounds 10 (N-(4-phenylbenzoyl)-leucylglycine nitrile) and 12 (N-(4-phenylbenzoyl)leucylmethionine nitrile) were found to be potent inhibitors of human cathepsin F, with Ki values nitriles from our study, a 3D activity landscape was generated to visualize structure-activity relationships for this series of cathepsin F inhibitors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Rate of hydrolysis in ATP synthase is fine-tuned by  -subunit motif controlling active site conformation

    KAUST Repository

    Beke-Somfai, T.; Lincoln, P.; Norden, B.

    2013-01-01

    Computer-designed artificial enzymes will require precise understanding of how conformation of active sites may control barrier heights of key transition states, including dependence on structure and dynamics at larger molecular scale. F(o)F(1) ATP synthase is interesting as a model system: a delicate molecular machine synthesizing or hydrolyzing ATP using a rotary motor. Isolated F(1) performs hydrolysis with a rate very sensitive to ATP concentration. Experimental and theoretical results show that, at low ATP concentrations, ATP is slowly hydrolyzed in the so-called tight binding site, whereas at higher concentrations, the binding of additional ATP molecules induces rotation of the central γ-subunit, thereby forcing the site to transform through subtle conformational changes into a loose binding site in which hydrolysis occurs faster. How the 1-Å-scale rearrangements are controlled is not yet fully understood. By a combination of theoretical approaches, we address how large macromolecular rearrangements may manipulate the active site and how the reaction rate changes with active site conformation. Simulations reveal that, in response to γ-subunit position, the active site conformation is fine-tuned mainly by small α-subunit changes. Quantum mechanics-based results confirm that the sub-Ångström gradual changes between tight and loose binding site structures dramatically alter the hydrolysis rate.

  20. Analysis of surface binding sites (SBSs) in carbohydrate active enzymes with focus on glycoside hydrolase families 13 and 77

    DEFF Research Database (Denmark)

    Cockburn, Darrell; Wilkens, Casper; Ruzanski, Christian

    2014-01-01

    Surface binding sites (SBSs) interact with carbohydrates outside of the enzyme active site. They are frequently situated on catalytic domains and are distinct from carbohydrate binding modules (CBMs). SBSs are found in a variety of enzymes and often seen in crystal structures. Notably about half ...

  1. 78 FR 12676 - Timing Requirements for the Submission of a Site Assessment Plan (SAP) or General Activities Plan...

    Science.gov (United States)

    2013-02-25

    ...: BOEM-2012-0077] RIN 1010-AD77 Timing Requirements for the Submission of a Site Assessment Plan (SAP) or... would amend the timing requirements for submitting a Site Assessment Plan (SAP) or General Activities... and grants will have a preliminary term of 12 months in which a lessee or grantee must submit a SAP or...

  2. Rate of hydrolysis in ATP synthase is fine-tuned by  -subunit motif controlling active site conformation

    KAUST Repository

    Beke-Somfai, T.

    2013-01-23

    Computer-designed artificial enzymes will require precise understanding of how conformation of active sites may control barrier heights of key transition states, including dependence on structure and dynamics at larger molecular scale. F(o)F(1) ATP synthase is interesting as a model system: a delicate molecular machine synthesizing or hydrolyzing ATP using a rotary motor. Isolated F(1) performs hydrolysis with a rate very sensitive to ATP concentration. Experimental and theoretical results show that, at low ATP concentrations, ATP is slowly hydrolyzed in the so-called tight binding site, whereas at higher concentrations, the binding of additional ATP molecules induces rotation of the central γ-subunit, thereby forcing the site to transform through subtle conformational changes into a loose binding site in which hydrolysis occurs faster. How the 1-Å-scale rearrangements are controlled is not yet fully understood. By a combination of theoretical approaches, we address how large macromolecular rearrangements may manipulate the active site and how the reaction rate changes with active site conformation. Simulations reveal that, in response to γ-subunit position, the active site conformation is fine-tuned mainly by small α-subunit changes. Quantum mechanics-based results confirm that the sub-Ångström gradual changes between tight and loose binding site structures dramatically alter the hydrolysis rate.

  3. A comprehensive search for calcium binding sites critical for TMEM16A calcium-activated chloride channel activity

    Science.gov (United States)

    Tien, Jason; Peters, Christian J; Wong, Xiu Ming; Cheng, Tong; Jan, Yuh Nung; Jan, Lily Yeh; Yang, Huanghe

    2014-01-01

    TMEM16A forms calcium-activated chloride channels (CaCCs) that regulate physiological processes such as the secretions of airway epithelia and exocrine glands, the contraction of smooth muscles, and the excitability of neurons. Notwithstanding intense interest in the mechanism behind TMEM16A-CaCC calcium-dependent gating, comprehensive surveys to identify and characterize potential calcium sensors of this channel are still lacking. By aligning distantly related calcium-activated ion channels in the TMEM16 family and conducting systematic mutagenesis of all conserved acidic residues thought to be exposed to the cytoplasm, we identify four acidic amino acids as putative calcium-binding residues. Alterations of the charge, polarity, and size of amino acid side chains at these sites alter the ability of different divalent cations to activate the channel. Furthermore, TMEM16A mutant channels containing double cysteine substitutions at these residues are sensitive to the redox potential of the internal solution, providing evidence for their physical proximity and solvent accessibility. DOI: http://dx.doi.org/10.7554/eLife.02772.001 PMID:24980701

  4. Use of project management approach for planning of decommissioning activities of a uranium mining site

    International Nuclear Information System (INIS)

    Ribeiro, Saulo F.Q.; Lage, Ricardo F.; Gomes, Danielle E.; Ogawa, Iukio

    2017-01-01

    The decommissioning of nuclear facilities in the fuel cycle is an extremely important factor for the continuity of nuclear program in any country, especially in that countries such as Brazil, where there are some facilities are in process of being dismantled or must be decommissioned in the medium and long term. Since the decommissioning is a process quite complex and expensive and for this reason, it must be handle with modern management practices for so that the chances of success are increased. This work aims to describe the management plan and the strategy adopted for the execution of the decommissioning and environmental remediation (D and ER) activities for the first uranium mine in Brazil, located in the Minas Gerais State and known as Unidade de Tratamento de Minério (UTM). This facility was operated between 1982 and 1995. All the economically recoverable uranium was extracted and nowadays there is no mining activity is underway and there are only research and laboratory activities are running in the site. The conceptual plans for decommissioning and remediation for this unit have been prepared and emergency activities were recommended. These activities are related to studies about drainage acid, ensure safety of dams, adequacy of CAKE II storage conditions and request for operating licenses for the decommissioning from IBAMA and the authorization from CNEN. The majority of the critical factors for decommissioning had their origin due the characteristics of the project have been implemented and has remained due to uncertainties in the decision-making process over time. This project has a set of variables that need to be analyzed considering different aspects as licensing and regulatory framework, radiological, technical and engineering issues, beyond costs, schedule, risks and human resources. In this sense, it was decided to adopt the good practices of project management, published by the Project Management Institute - PMI and to give a differentiated

  5. Use of project management approach for planning of decommissioning activities of a uranium mining site

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Saulo F.Q.; Lage, Ricardo F.; Gomes, Danielle E.; Ogawa, Iukio, E-mail: quintao.saulo@gmail.com, E-mail: rflage@gmail.com, E-mail: danielle@inb.gov.br, E-mail: iukio@inb.gov.br [Indústrias Nucleares do Brasil (INB), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    The decommissioning of nuclear facilities in the fuel cycle is an extremely important factor for the continuity of nuclear program in any country, especially in that countries such as Brazil, where there are some facilities are in process of being dismantled or must be decommissioned in the medium and long term. Since the decommissioning is a process quite complex and expensive and for this reason, it must be handle with modern management practices for so that the chances of success are increased. This work aims to describe the management plan and the strategy adopted for the execution of the decommissioning and environmental remediation (D and ER) activities for the first uranium mine in Brazil, located in the Minas Gerais State and known as Unidade de Tratamento de Minério (UTM). This facility was operated between 1982 and 1995. All the economically recoverable uranium was extracted and nowadays there is no mining activity is underway and there are only research and laboratory activities are running in the site. The conceptual plans for decommissioning and remediation for this unit have been prepared and emergency activities were recommended. These activities are related to studies about drainage acid, ensure safety of dams, adequacy of CAKE II storage conditions and request for operating licenses for the decommissioning from IBAMA and the authorization from CNEN. The majority of the critical factors for decommissioning had their origin due the characteristics of the project have been implemented and has remained due to uncertainties in the decision-making process over time. This project has a set of variables that need to be analyzed considering different aspects as licensing and regulatory framework, radiological, technical and engineering issues, beyond costs, schedule, risks and human resources. In this sense, it was decided to adopt the good practices of project management, published by the Project Management Institute - PMI and to give a differentiated

  6. Biological role of site-specific O-glycosylation in cell adhesion activity and phosphorylation of osteopontin.

    Science.gov (United States)

    Oyama, Midori; Kariya, Yoshinobu; Kariya, Yukiko; Matsumoto, Kana; Kanno, Mayumi; Yamaguchi, Yoshiki; Hashimoto, Yasuhiro

    2018-05-09

    Osteopontin (OPN) is an extracellular glycosylated phosphoprotein that promotes cell adhesion by interacting with several integrin receptors. We previously reported that an OPN mutant lacking five O-glycosylation sites (Thr 134 /Thr 138 /Thr 143 /Thr 147 /Thr 152 ) in the threonine/proline-rich region increased cell adhesion activity and phosphorylation compared with the wild type. However, the role of O-glycosylation in cell adhesion activity and phosphorylation of OPN remains to be clarified. Here, we show that site-specific O-glycosylation in the threonine/proline-rich region of OPN affects its cell adhesion activity and phosphorylation independently and/or synergistically. Using site-directed mutagenesis, we found that OPN mutants with substitution sets of Thr 134 /Thr 138 or Thr 143 /Thr 147 /Thr 152 had decreased and increased cell adhesion activity, respectively. In contrast, the introduction of a single mutation into the O-glycosylation sites had no effect on OPN cell adhesion activity. An adhesion assay using function-blocking antibodies against αvβ3 and β1 integrins, as well as αvβ3 integrin-overexpressing A549 cells, revealed that site-specific O-glycosylation affected the association of OPN with the two integrins. Phosphorylation analyses using phos-tag and LC-MS/MS indicated that phosphorylation levels and sites were influenced by the O-glycosylation status, although the number of O-glycosylation sites was not correlated with the phosphorylation level in OPN. Furthermore, a correlation analysis between phosphorylation level and cell adhesion activity in OPN mutants with the site-specific O-glycosylation showed that they were not always correlated. These results provide conclusive evidence of a novel regulatory mechanism of cell adhesion activity and phosphorylation of OPN by site-specific O-glycosylation. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  7. Glycosylation site-targeted PEGylation of glucose oxidase retains native enzymatic activity.

    Science.gov (United States)

    Ritter, Dustin W; Roberts, Jason R; McShane, Michael J

    2013-04-10

    Targeted PEGylation of glucose oxidase at its glycosylation sites was investigated to determine the effect on enzymatic activity, as well as the bioconjugate's potential in an optical biosensing assay. Methoxy-poly(ethylene glycol)-hydrazide (4.5kDa) was covalently coupled to periodate-oxidized glycosylation sites of glucose oxidase from Aspergillus niger. The bioconjugate was characterized using gel electrophoresis, liquid chromatography, mass spectrometry, and dynamic light scattering. Gel electrophoresis data showed that the PEGylation protocol resulted in a drastic increase (ca. 100kDa) in the apparent molecular mass of the protein subunit, with complete conversion to the bioconjugate; liquid chromatography data corroborated this large increase in molecular size. Mass spectrometry data proved that the extent of PEGylation was six poly(ethylene glycol) chains per glucose oxidase dimer. Dynamic light scattering data indicated the absence of higher-order oligomers in the PEGylated GOx sample. To assess stability, enzymatic activity assays were performed in triplicate at multiple time points over the course of 29 days in the absence of glucose, as well as before and after exposure to 5% w/v glucose for 24h. At a confidence level of 95%, the bioconjugate's performance was statistically equivalent to native glucose oxidase in terms of activity retention over the 29 day time period, as well as following the 24h glucose exposure. Finally, the bioconjugate was entrapped within a poly(2-hydroxyethyl methacrylate) hydrogel containing an oxygen-sensitive phosphor, and the construct was shown to respond approximately linearly with a 220±73% signal change (n=4, 95% confidence interval) over the physiologically-relevant glucose range (i.e., 0-400mg/dL); to our knowledge, this represents the first demonstration of PEGylated glucose oxidase incorporated into an optical biosensing assay. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. The Use of Social Networking Sites in Job Related Activities: A Cross-cultural Comparison

    Directory of Open Access Journals (Sweden)

    Małgorzata Bartosik-Purgat

    2017-06-01

    Full Text Available Objective: The main objective of the paper is to identify the use of Social Networking Sites (SNSs in job related activities and indicate the interdependencies between these activities and age, gender, as well as education in culturally diversified markets (China, Poland, Turkey, the United States. Research Design & Methods: In the exploratory empirical study the authors used two research methods: PAPI (Paper and Pen Personal Interview and CAWI (Computer Assisted Web Interview. The empirical data were collected in 2016 and the total number of respondents from four culturally diversified countries was 1246. Findings: The analysis with the use of Kruskal-Wallis and Dunn post-hoc tests showed that the Turkish respondents most often use SNSs for job related activities, while it is the least often done by the studied Americans. Moreover, from among the studied factors (gender, age and education level that differentiate the SNSs usage for job related activities in a statistically significant way age is of greatest importance. Implications & Recommendations: The results of the research provide implications for the recruitment policy of multinational enterprises (MNEs. Since more and more enterprises use SNSs in order to look for new employees and advertise themselves as employers (employer branding, the identified interdependencies between the SNSs activities and the analysed factors can support firm attempts to develop the proper recruitment policy taking into account the cultural diversity of potential workers. Contribution & Value Added: There are not many studies in the literature which present the usage of SNSs for job related activities from the perspective of individual users in the cross-cultural approach. The majority of studies are related to the usage of SNSs by enterprises in the recruitment process.

  9. Widely available active sites on Ni2P for electrochemical hydrogen evolution - insights from first principles calculations

    DEFF Research Database (Denmark)

    Hansen, Martin Hangaard; Stern, Lucas-Alexandre; Feng, Ligang

    2015-01-01

    We present insights into the mechanism and the active site for hydrogen evolution on nickel phosphide (Ni2P). Ni2P was recently discovered to be a very active non-precious hydrogen evolution catalyst. Current literature attributes the activity of Ni2P to a particular site on the (0001) facet....... In the present study, using Density Functional Theory (DFT) calculations, we show that several widely available low index crystal facets on Ni2P have better properties for a high catalytic activity. DFT calculations were used to identify moderately bonding nickel bridge sites and nickel hollow sites for hydrogen...... adsorption and to calculate barriers for the Tafel pathway. The investigated surfaces in this study were the (10 (1) over bar0), ((1) over bar(1) over bar 20), (11 (2) over bar0), (11 (2) over bar1) and (0001) facets of the hexagonal Ni2P crystal. In addition to the DFT results, we present experiments on Ni2...

  10. Assessment of national systems for obtaining local acceptance of waste management siting and routing activities

    Energy Technology Data Exchange (ETDEWEB)

    Paige, H.W.; Lipman, D.S.; Owens, J.E.

    1980-07-01

    There is a rich mixture of formal and informal approaches being used in our sister nuclear democracies in their attempts to deal with the difficulties of obtaining local acceptance for siting of waste management facilities and activities. Some of these are meeting with a degree of success not yet achieved in the US. Although this survey documents and assesses many of these approaches, time did not permit addressing in any detail their relevance to common problems in the US. It would appear the US could benefit from a periodic review of the successes and failures of these efforts, including analysis of their applicability to the US system. Of those countries (Germany, Sweden, Switzerland, Japan, Belgium, and the US) who are working to a time table for the preparation of a high-level waste (HLW) repository, Germany is the only country to have gained local siting acceptance for theirs. With this (the most difficult of siting problems) behind them they appear to be in the best overall condition relative to waste management progress and plans. This has been achieved without a particularly favorable political structure, made up for by determination on the part of the political leadership. Of the remaining three countries studied (France, UK and Canada) France, with its AVM production facility, is clearly the world leader in the HLW immobilization aspect of waste management. France, Belgium and the UK appear to have the least favorable political structures and environments for arriving at waste management decisions. US, Switzerland and Canada appear to have the least favorable political structures and environments for arriving at waste management decisions.

  11. Relationships between waste physicochemical properties, microbial activity and vegetation at coal ash and sludge disposal sites.

    Science.gov (United States)

    Woch, Marcin W; Radwańska, Magdalena; Stanek, Małgorzata; Łopata, Barbara; Stefanowicz, Anna M

    2018-06-11

    The aim of the study was to assess the relationships between vegetation, physicochemical and microbial properties of substrate at coal ash and sludge disposal sites. The study was performed on 32 plots classified into 7 categories: dried ash sedimentation ponds, dominated by a grass Calamagrostis epigejos (AH-Ce), with the admixture of Pinus sylvestris (AH-CePs) or Robinia pseudoacacia (AH-CeRp), dry ash landfill dominated by Betula pendula and Pinus sylvestris (AD-BpPs) or Salix viminalis (AD-Sv) and coal sludge pond with drier parts dominated by Tussilago farfara (CS-Tf) and the wetter ones by Cyperus flavescens (CS-Cf). Ash sites were covered with soil layer imported as a part of technical reclamation. Ash had relatively high concentrations of some alkali and alkaline earth metals, Mn and pH, while coal sludge had high water and C, S, P and K contents. Concentrations of heavy metals were lower than allowable limits in all substrate types. Microbial biomass and, particularly, enzymatic activity in ash and sludge were generally low. The only exception were CS-Tf plots characterized by the highest microbial biomass, presumably due to large deposits of organic matter that became available for aerobic microbial biomass when water level fell. The properties of ash and sludge adversely affected microbial biomass and enzymatic activity as indicated by significant negative correlations between the content of alkali/alkaline earth metals, heavy metals, and macronutrients with enzymatic activity and/or microbial biomass, as well as positive correlations of these parameters with metabolic quotient (qCO 2 ). Plant species richness and cover were relatively high, which may be partly associated with alleviating influence of soil covering the ash. The effect of the admixture of R. pseudoacacia or P. sylvestris to stands dominated by C. epigejos was smaller than expected. The former species increased NNH 4 , NNO 3 and arylsulfatase activity, while the latter reduced activity of

  12. Synthesis of a molecularly defined single-active site heterogeneous catalyst for selective oxidation of N-heterocycles.

    Science.gov (United States)

    Zhang, Yujing; Pang, Shaofeng; Wei, Zhihong; Jiao, Haijun; Dai, Xingchao; Wang, Hongli; Shi, Feng

    2018-04-13

    Generally, a homogeneous catalyst exhibits good activity and defined active sites but it is difficult to recycle. Meanwhile, a heterogeneous catalyst can easily be reused but its active site is difficult to reveal. It is interesting to bridge the gap between homogeneous and heterogeneous catalysis via controllable construction of a heterogeneous catalyst containing defined active sites. Here, we report that a molecularly defined, single-active site heterogeneous catalyst has been designed and prepared via the oxidative polymerization of maleimide derivatives. These polymaleimide derivatives can be active catalysts for the selective oxidation of heterocyclic compounds to quinoline and indole via the recycling of -C=O and -C-OH groups, which was confirmed by tracing the reaction with GC-MS using maleimide as the catalyst and by FT-IR analysis with polymaleimide as the catalyst. These results might promote the development of heterogeneous catalysts with molecularly defined single active sites exhibiting a comparable activity to homogeneous catalysts.

  13. The response of mulberry trees after seedling hardening to summer drought in the hydro-fluctuation belt of Three Gorges Reservoir Areas.

    Science.gov (United States)

    Huang, Xiaohui; Liu, Yun; Li, Jiaxing; Xiong, Xingzheng; Chen, Yang; Yin, Xiaohua; Feng, Dalan

    2013-10-01

    Interest has developed in the potential of mulberry (Morus alba), a woody perennial, for revegetating the hydro-fluctuation belt of the Three Gorges Reservoir due to its resistance to water-logging stress. To be useful, the trees must also be able to withstand dry conditions in summer when temperatures can be very high and droughts become severe quickly. Here, we report a study in which mulberry seedlings were grown in a greenhouse under a variety of simulated soil water conditions reflecting potential summer scenarios in the hydro-fluctuation belt of the Three Gorges Reservoir Area. We compared the responses of two pretreatment groups of mulberry seedlings to different levels of drought stress. The pretreatment groups differed with respect to drought hardening: the daily-managed (DM) group had relative soil moisture held constant in the range 70-80 %, while the drought-hardened (DH) group had relative soil moisture held constant at 40-50 %. Following the month-long pretreatment of seedlings, the two groups of young trees (DM and DH) were then respectively subjected to three levels of drought stress for a month: normal watering, moderate drought stress, and severe drought stress. A series of measurements comparing the physiological status of the plants in the two groups were then made, and the following results were obtained: (1) As drought stress increased, the heights, base diameters, root surface areas, photosynthetic rates (Pn), stomatal conductances (Gs), and transpiration rates (Tr) of the mulberry trees in both groups (DM and DH) decreased significantly, while the specific root area and abscisic acid (ABA) contents had increasing trends. Root activity and instantaneous water use efficiency of mulberry trees in both groups (DM and DH) were all raised under drought stress conditions than under normal watering, but the root/shoot ratio and leaf water potential were lowered. (2) At the same level of soil water content, the heights, base diameters, root

  14. Reconstructing the 1935 Columbia River Gorge: A Topographic and Orthophoto Experiment

    Science.gov (United States)

    Fonstad, M. A.; Major, J. H.; O'Connor, J. E.; Dietrich, J. T.

    2017-12-01

    The last decade has seen a revolution in the mapping of rivers and near-river environments. Much of this has been associated with a new type of photogrammetry: structure from motion (SfM) and multi-view stereo techniques. Through SfM, 3D surfaces are reconstructed from nonstructured image groups with poorly calibrated cameras whose locations need not be known. Modern SfM imaging is greatly improved by careful flight planning, well-planned ground control or high-precision direct georeferencing, and well-understood camera optics. The ease of SfM, however, begs the question: how well does it work on archival photos taken without the foreknowledge of SfM techniques? In 1935, the Army Corps of Engineers took over 800 vertical aerial photos for a 160-km-long stretch of the Columbia River Gorge and adjacent areas in Oregon and Washington. These photos pre-date completion of three hydroelectric dams and reservoirs in this reach, and thus provide rich information on the historic pre-dam riverine, geologic, and cultural environments. These photos have little to no metadata associated with them, such as camera calibration reports, so traditional photogrammetry techniques are exceeding difficult to apply. Instead, we apply SfM to these archival photos, and test the resulting digital elevation model (DEM) against lidar data for features inferred to be unchanged in the past 80 years. Few, if any, of the quality controls recommended for SfM are available for these 1935 photos; they are scanned paper positives with little overlap taken with an unknown optical system in high altitude flight paths. Nevertheless, in almost all areas, the SfM analysis produced a high quality orthophoto of the gorge with low horizontal errors - most better than a few meters. The DEM created looks highly realistic, and in many areas has a vertical error of a few meters. However, the vertical errors are spatially inconsistent, with some wildly large, likely because of the many poorly constrained links in

  15. The Sasso Pizzuto landslide dam and seismically induced rockfalls along the Nera River gorge (Central Italy).

    Science.gov (United States)

    Romeo, Saverio; Di Matteo, Lucio; Melelli, Laura; Cencetti, Corrado; Dragoni, Walter; Fredduzzi, Andrea; De Rosa, Pierluigi

    2017-04-01

    The seismically induced landslides are among the most destructive and dangerous effects of an earthquake. In the Italian contest, this is also documented by a national catalogue that collects data related to earthquake-induced ground failures in the last millennium (CEDIT database). In particular, Central Italy has been affected by several historical landslides triggered by significant earthquakes, the last of which occurred in August-October 2016, representing the Italian strongest event after the 1980 Irpinia earthquake (Mw 6.9). The study presents the effects of recent seismically induced rockfalls occurred within the Central Italy seismic sequence (October 30, 2016) along the Nera River gorge between Umbria and Marche. The study area is completely included in the Monti Sibillini National Park, where the highest mountain chain in the Umbrian-Marchean Apennine is located. Most of rockfalls have affected the "Maiolica" formation, a stratified and fractured pelagic limestone dating to the Early Cretaceous. The seismic sequence produced diffuse instabilities along the SP 209 road within the Nera River gorge: boulders, debris accumulations and diffuse rockfalls have been mapped. Most of boulders have size ranging from 0.3 to 2.0 m in diameter. Although several strong quakes (Mw > 5) occurred during the August-October sequence, only the main quake triggered the Sasso Pizzuto rockfall producing a landslide dam along the Nera River. The landslide appears to have originated as a wedge failure, which evolved to free fall when the rock block lost the contact with the stable rock mass. In other words, the quake produced the "explosion" of the rock wall allowing the rockfall process. Once the rock mass reached the toe of the slope, it was broken triggering a rock avalanche that obstructed both the Nera River and SP 209 road. With the aim to estimate the total volume of involved rock, a field survey was carried out by using a laser rangefinder. Remote measures were acquired

  16. Reservoir-induced landslides and risk control in Three Gorges Project on Yangtze River, China

    Directory of Open Access Journals (Sweden)

    Yueping Yin

    2016-10-01

    Full Text Available The Three Gorges region in China was basically a geohazard-prone area prior to construction of the Three Gorges Reservoir (TGR. After construction of the TGR, the water level was raised from 70 m to 175 m above sea level (ASL, and annual reservoir regulation has caused a 30-m water level difference after impoundment of the TGR since September 2008. This paper first presents the spatiotemporal distribution of landslides in six periods of 175 m ASL trial impoundments from 2008 to 2014. The results show that the number of landslides sharply decreased from 273 at the initial stage to less than ten at the second stage of impoundment. Based on this, the reservoir-induced landslides in the TGR region can be roughly classified into five failure patterns, i.e. accumulation landslide, dip-slope landslide, reversed bedding landslide, rockfall, and karst breccia landslide. The accumulation landslides and dip-slope landslides account for more than 90%. Taking the Shuping accumulation landslide (a sliding mass volume of 20.7 × 106 m3 in Zigui County and the Outang dip-slope landslide (a sliding mass volume of about 90 × 106 m3 in Fengjie County as two typical cases, the mechanisms of reactivation of the two landslides are analyzed. The monitoring data and factor of safety (FOS calculation show that the accumulation landslide is dominated by water level variation in the reservoir as most part of the mass body is under 175 m ASL, and the dip-slope landslide is controlled by the coupling effect of reservoir water level variation and precipitation as an extensive recharge area of rainfall from the rear and the front mass is below 175 m ASL. The characteristics of landslide-induced impulsive wave hazards after and before reservoir impoundment are studied, and the probability of occurrence of a landslide-induced impulsive wave hazard has increased in the reservoir region. Simulation results of the Ganjingzi landslide in Wushan County indicate the

  17. The influence of small-mammal burrowing activity on water storage at the Hanford Site

    International Nuclear Information System (INIS)

    Landeen, D.S.

    1994-01-01

    This paper summarizes the activities that were conducted in support of the long-term surface barrier development program by Westinghouse Hanford Company to determine the degree that small-mammal burrow systems affect the loss or retention of water in the soils at the Hanford Site in Washington state. An animal intrusion lysimeter facility was constructed, consisting of two outer boxes buried at grade, which served as receptacles for six animal intrusion lysimeters. Small burrowing animals common the Hanford Site were introduced over a 3- to 4-month period. Supplemental precipitation was added monthly to three of the lysimeters with a rainfall simulator (rainulator). Information collected from the five tests indicated that (1) during summer months, water was lost in all the lysimeters, including the supplemental precipitation added with the rainulator; and (2) during winter months, all lysimeters gained water. The data indicate little difference in the amount of water stored between control and animal lysimeters. The overall water loss was attributed to surface evaporation, a process that occurred equally in control and treatment lysimeters. Other causes of water loss are a result of (1) constant soil turnover and subsequent drying, and (2) burrow ventilation effects. This suggests that burrow systems will not contribute to any significant water storage at depth and, in fact, may enhance the removal of water from the soil

  18. It takes two to tango: defining an essential second active site in pyridoxal 5'-phosphate synthase.

    Directory of Open Access Journals (Sweden)

    Cyril Moccand

    Full Text Available The prevalent de novo biosynthetic pathway of vitamin B6 involves only two enzymes (Pdx1 and Pdx2 that form an ornate multisubunit complex functioning as a glutamine amidotransferase. The synthase subunit, Pdx1, utilizes ribose 5-phosphate and glyceraldehyde 3-phosphate, as well as ammonia derived from the glutaminase activity of Pdx2 to directly form the cofactor vitamer, pyridoxal 5'-phosphate. Given the fact that a single enzyme performs the majority of the chemistry behind this reaction, a complicated mechanism is anticipated. Recently, the individual steps along the reaction co-ordinate are beginning to be unraveled. In particular, the binding of the pentose substrate and the first steps of the reaction have been elucidated but it is not known if the latter part of the chemistry, involving the triose sugar, takes place in the same or a disparate site. Here, we demonstrate through the use of enzyme assays, enzyme kinetics, and mutagenesis studies that indeed a second site is involved in binding the triose sugar and moreover, is the location of the final vitamin product, pyridoxal 5'-phosphate. Furthermore, we show that product release is triggered by the presence of a PLP-dependent enzyme. Finally, we provide evidence that a single arginine residue of the C terminus of Pdx1 is responsible for coordinating co-operativity in this elaborate protein machinery.

  19. Microbial community changes along the active seepage site of one cold seep in the Red Sea.

    KAUST Repository

    Cao, Huiluo

    2015-07-21

    The active seepage of the marine cold seeps could be a critical process for the exchange of energy between the submerged geosphere and the sea floor environment through organic-rich fluids, potentially even affecting surrounding microbial habitats. However, few studies have investigated the associated microbial community changes. In the present study, 16S rRNA genes were pyrosequenced to decipher changes in the microbial communities from the Thuwal seepage point in the Red Sea to nearby marine sediments in the brine pool, normal marine sediments and water, and benthic microbial mats. An unexpected number of reads from unclassified groups were detected in these habitats; however, the ecological functions of these groups remain unresolved. Furthermore, ammonia-oxidizing archaeal community structures were investigated using the ammonia monooxygenase subunit A (amoA) gene. Analysis of amoA showed that planktonic marine habitats, including seeps and marine water, hosted archaeal ammonia oxidizers that differed from those in microbial mats and marine sediments, suggesting modifications of the ammonia oxidizing archaeal (AOA) communities along the environmental gradient from active seepage sites to peripheral areas. Changes in the microbial community structure of AOA in different habitats (water vs. sediment) potentially correlated with changes in salinity and oxygen concentrations. Overall, the present results revealed for the first time unanticipated novel microbial groups and changes in the ammonia-oxidizing archaea in response to environmental gradients near the active seepages of a cold seep.

  20. Natural resource management activities at the Savannah River Site. Environmental Assessment

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    This environmental assessment (EA) reviews the environmental consequences of ongoing natural resource management activities on the Savannah River Site (SRS). Appendix A contains the Natural Resources Management Plant (NRMP). While several SRS organizations have primary responsibilities for different elements of the plan, the United States Department of Agriculture (USDA), Forest Service, Savannah River Forest Station (SRFS) is responsible for most elements. Of the river scenarios defined in 1985, the High-Intensity Management alternative established the upper bound of environmental consequences; it represents a more intense level of resource management than that being performed under current resource management activities. This alternative established compliance mechanisms for several natural resource-related requirements and maximum practical timber harvesting. Similarly, the Low-Intensity Management alternative established the lower bound of environmental consequences and represents a less intense level of resource management than that being performed under current resource management activities. This alternative also established compliance mechanisms, but defined a passively managed natural area. The Proposed Action of this EA describes the current level of multiple-natural resource management. This EA reviews the proposed action, and the high and low intensity alternative scenarios.

  1. Microbial community changes along the active seepage site of one cold seep in the Red Sea.

    KAUST Repository

    Cao, Huiluo; Zhang, Weipeng; Wang, Yong; Qian, Pei-Yuan

    2015-01-01

    The active seepage of the marine cold seeps could be a critical process for the exchange of energy between the submerged geosphere and the sea floor environment through organic-rich fluids, potentially even affecting surrounding microbial habitats. However, few studies have investigated the associated microbial community changes. In the present study, 16S rRNA genes were pyrosequenced to decipher changes in the microbial communities from the Thuwal seepage point in the Red Sea to nearby marine sediments in the brine pool, normal marine sediments and water, and benthic microbial mats. An unexpected number of reads from unclassified groups were detected in these habitats; however, the ecological functions of these groups remain unresolved. Furthermore, ammonia-oxidizing archaeal community structures were investigated using the ammonia monooxygenase subunit A (amoA) gene. Analysis of amoA showed that planktonic marine habitats, including seeps and marine water, hosted archaeal ammonia oxidizers that differed from those in microbial mats and marine sediments, suggesting modifications of the ammonia oxidizing archaeal (AOA) communities along the environmental gradient from active seepage sites to peripheral areas. Changes in the microbial community structure of AOA in different habitats (water vs. sediment) potentially correlated with changes in salinity and oxygen concentrations. Overall, the present results revealed for the first time unanticipated novel microbial groups and changes in the ammonia-oxidizing archaea in response to environmental gradients near the active seepages of a cold seep.

  2. Monitoring N2O Production Using a cNOR Modeled Active Site

    Science.gov (United States)

    Griffiths, Z. G.; Hegg, E. L.; Finders, C.; Haslun, J. A.

    2017-12-01

    Nitrous oxide (N2O) is a potent greenhouse gas with a 100-year global warming potential 265-296 times greater than carbon dioxide (CO2). It is the leading contributor to ozone depletion and can persist in the stratosphere for approximately 114 years. Hence, understanding the sources of atmospheric N2O emissions is critical to remediating the effects of climate change. Agricultural activities are the largest contributor to N2O emissions in the U.S. with microbial nitrification and denitrification as the dominating soil processes. The enzyme cytochrome c nitric oxide reductase (cNOR) is involved in bacterial denitrification. It is often difficult to study the enzymes involved in biotic N2O production, hence, model enzymes are a useful tool. The enzyme I107EFeBMb, a sperm whale myoglobin derivative, models the active site of cNOR and was used to simulate the anaerobic reduction of NO to N2O by cNOR. Dithionite was used to induce the catalytic activity of I107EFeBMb by reducing the enzyme. However, dithionite is a strong reductant that is capable of reducing NO to N2O directly. Therefore, the dithionite-enzyme mixture was passed through a size-exclusion column to isolate the reduced enzyme. This reduced and purified enzyme was then utilized to investigate N2O production from NO. This project will provide both an enzymatic and abiotic model to study N2O production.

  3. DAF in diabetic patients is subject to glycation/inactivation at its active site residues.

    Science.gov (United States)

    Flückiger, Rudolf; Cocuzzi, Enzo; Nagaraj, Ram H; Shoham, Menachem; Kern, Timothy S; Medof, M Edward

    2018-01-01

    Decay accelerating factor (DAF or CD55) is a cell associated C3 and C5 convertase regulator originally described in terms of protection of self-cells from systemic complement but now known to modulate adaptive T cell responses. It is expressed on all cell types. We investigated whether nonenzymatic glycation could impair its function and potentially be relevant to complications of diabetes mellitus and other conditions that result in nonenzymatic glycation including cancer, Alzheimer's disease, and aging. Immunoblots of affinity-purified DAF from erythrocytes of patients with diabetes showed pentosidine, glyoxal-AGEs, carboxymethyllysine, and argpyrimidine. HPLC/MS analyses of glucose modified DAF localized the sites of AGE modifications to K 125 adjacent to K 126 , K 127 at the junction of CCPs2-3 and spatially near R 96 , and R 100 , all identified as being critical for DAF's function. Functional analyses of glucose or ribose treated DAF protein showed profound loss of its regulatory activity. The data argue that de-regulated activation of systemic complement and de-regulated activation of T cells and leukocytes could result from non-enzymatic glycation of DAF. Copyright © 2017. Published by Elsevier Ltd.

  4. Actinobacterial diversity in limestone deposit sites in Hundung, Manipur (India and their antimicrobial activities

    Directory of Open Access Journals (Sweden)

    Salam eNimaichand

    2015-05-01

    Full Text Available Studies on actinobacterial diversity in limestone habitats are scarce. This paper reports profiling of actinobacteria isolated from Hundung limestone samples in Manipur, India using ARDRA as the molecular tool for preliminary classification. A total of 137 actinobacteria were clustered into 31 phylotypic groups based on the ARDRA pattern generated and representative of each group was subjected to 16S rRNA gene sequencing. Generic diversity of the limestone isolates consisted of Streptomyces (15 phylotypic groups, Micromonospora (4, Amycolatopsis (3, Arthrobacter (3, Kitasatospora (2, Janibacter (1, Nocardia (1, Pseudonocardia (1 and Rhodococcus (1. Considering the antimicrobial potential of these actinobacteria, 19 showed antimicrobial activities against at least one of the bacterial and candidal test pathogens, while 45 exhibit biocontrol activities against at least one of the rice fungal pathogens. Out of the 137 actinobacterial isolates, 118 were found to have at least one of the three biosynthetic gene clusters (PKS-I, PKS-II, NRPS. The results indicate that 86% of the strains isolated from Hundung limestone deposit sites possessed biosynthetic gene clusters of which 40% exhibited antimicrobial activities. It can, therefore, be concluded that limestone habitat is a promising source for search of novel secondary metabolites.

  5. Design criteria applicable to the environmental restoration of sites affected by uranium mining activities in the past

    International Nuclear Information System (INIS)

    Carboneras, P.; Sanchez, M.

    1993-01-01

    In this paper the authors discuss the basic aspects to be considered while evaluating different alternatives to perform environmental restoration of sites affected by naturally occurring radionuclides, enhanced by human actions, as is the case in some old uranium mining activities. The discussion is confined to sites where radiation hazards had existed forever (sites with uranium deposits) and where the mining activities have introduced several factors modifying the initial situation, leading to the now existing one, requiring intervention as decided by the relevant authorities, in accordance with recommendations of ICRP60

  6. Design criteria applicable to the environmental restoration of sites affected by uranium mining activities in the past

    Energy Technology Data Exchange (ETDEWEB)

    Carboneras, P. [ENRESA, Madrid (Spain); Sanchez, M. [INITEC, Madrid (Spain)

    1993-12-31

    In this paper the authors discuss the basic aspects to be considered while evaluating different alternatives to perform environmental restoration of sites affected by naturally occurring radionuclides, enhanced by human actions, as is the case in some old uranium mining activities. The discussion is confined to sites where radiation hazards had existed forever (sites with uranium deposits) and where the mining activities have introduced several factors modifying the initial situation, leading to the now existing one, requiring intervention as decided by the relevant authorities, in accordance with recommendations of ICRP60.

  7. Design and performance of the Savannah River Site Billet Active Well Coincidence Counter

    International Nuclear Information System (INIS)

    Griffin, J.C.; Sadowski, E.T.

    1991-01-01

    The Savannah River Site (SRS) has acquired, installed, and tested a custom-built Billet Active Well (neutron) Coincidence Counter (BAWCC). The BAWCC is used to make accountability measurements of the 235 U content of U-Al coextrusion billets in the SRS fuel fabrication facility. The instrument design incorporates a unique center-source configuration, with two moderated americium-lithium (AmLi) neutron sources located in a central spindle that inserts through the center hole of the U-Al billets. This configuration, a result of earlier experimental studies at SRS, yields improved response and precision for billet assay when compared to the standard AWCC source arrangement. Initial tests of the BAWCC at SRS have yielded one-sigma uncertainties of 0.8--1.0% for a fifteen-minute assay. This paper will describe the design, testing program and performance characteristics of the BAWCC

  8. Neutron activation analysis in an industrial laboratory using an off-site nuclear reactor

    International Nuclear Information System (INIS)

    Osborn, T.W.; Broering, W.B.

    1977-01-01

    A multifunctional research laboratory, such as Procter and Gamble's Miami Valley Laboratories, requires elemental analyses on many materials. A general survey technique is important even if the information it provides is incomplete or is less precise than single element analyses. Procter and Gamble has developed neutron activation analysis (NAA) capabilities using a nuclear reactor several hundred miles away. The concentration of 40 to 50 elements can be determined in a variety of matrices. We have found NAA to be a powerful supplement to some of the more classical analytical techniques even without having an on-site neutron source. We have also found an automated data acquisition system to be essential for the successful application of NAA in an industrial laboratory

  9. Comparison of POLDER Cloud Phase Retrievals to Active Remote Sensors Measurements at the ARM SGP Site

    International Nuclear Information System (INIS)

    Riedi, J.; Goloub, P.; Marchand, Roger T.

    2001-01-01

    In our present study, cloud boundaries derived from a combination of active remote sensors at the ARM SGP site are compared to POLDER cloud top phase index which is derived from polarimetric measurements using an innovative method. This approach shows the viability of the POLDER phase retrieval algorithm, and also leads to interesting results. In particular, the analysis demonstrates the sensitivity of polarization measurements to ice crystal shape and indicates that occurrence of polycrystalline ice clouds has to be taken into account in order to improve the POLDER phase retrieval algorithm accuracy. Secondly, the results show that a temperature threshold of 240 K could serve for cloud top particle phase classification. Considering the limitations of the analysis, the temperature threshold could be biased high, but not by more than about 5 degrees

  10. The activities of the IAEA in nuclear power station site studies

    International Nuclear Information System (INIS)

    Farges, L.

    1980-01-01

    This short review of IAEA activities in nuclear power station site studies gives the impression of a multiform action of unequal importance according to the projects and geographically very dispersed. It should be realised that the Agency does not possess the initiative in the development of this action and is dependent upon its member states for the preparation and finalizing of programmes, and it cannot undertake studies on the spot without the formal request of the state concerned. Furthermore, it does not have limitless means and a selection is made among the requests from the various member states which sometimes takes into account criteria other than those of a scientific or technical nature [fr

  11. Can Crystal Symmetry and Packing Influence the Active Site Conformation of Homohexameric Purine Nucleoside Phosphorylases?

    Directory of Open Access Journals (Sweden)

    Marija Luić

    2016-06-01

    Full Text Available It is generaly believed that enzymes retain most of their functionality in the crystal form due to the large solvent content of protein crystals. This is facilitated by the fact that their natural environment in solution is not too far from the one found in the crystal form. Nevertheless, if the nature of the enzyme is such to require conformational changes, overcoming of the crystal packing constraints may prove to be too difficult. Such conformational change is present in one class of enzymes (purine nucleoside phosphorylases, that is the subject of our scientific interest for many years. The influence of crystal symmetry and crystal packing on the conformation of the active sites in the case of homohexameric purine nucleoside phosphorylases is presented and analysed. This work is licensed under a Creative Commons Attribution 4.0 International License.

  12. How to awaken your nanomachines: Site-specific activation of focal adhesion kinases through ligand interactions.

    Science.gov (United States)

    Walkiewicz, Katarzyna W; Girault, Jean-Antoine; Arold, Stefan T

    2015-10-01

    The focal adhesion kinase (FAK) and the related protein-tyrosine kinase 2-beta (Pyk2) are highly versatile multidomain scaffolds central to cell adhesion, migration, and survival. Due to their key role in cancer metastasis, understanding and inhibiting their functions are important for the development of targeted therapy. Because FAK and Pyk2 are involved in many different cellular functions, designing drugs with partial and function-specific inhibitory effects would be desirable. Here, we summarise recent progress in understanding the structural mechanism of how the tug-of-war between intramolecular and intermolecular interactions allows these protein 'nanomachines' to become activated in a site-specific manner. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Main Principles of the Organization of Decommissioning Activities for Legacy Sites

    Energy Technology Data Exchange (ETDEWEB)

    Mikheykin, S.V., E-mail: Mikheykin@rosrao.ru [Department of Techniques for Remediation, Federal State Unitary Enterprise ' RosRAO' , Moscow (Russian Federation)

    2013-08-15

    As a result of more than 60 years development of nuclear industry in the former Soviet Union and in the Russian Federation there has accumulated a number of unresolved problems associated with contamination of facilities and environment during the early stages of research and industrial activities. Prior to the year 2000 most of the problems were solved slowly; the main decisions were postponed for the future. During that time were done the local works for the rehabilitation of contaminated sites. The Federal Target Programme ''Nuclear and Radiation Safety for 2008 and for the period to 2015'' was adopted in 2008. Analysis of accumulated experience as result of previous work on decontamination to develop new project management system for the rehabilitation of the nuclear legacy is needed. This CRP contribution is aimed at solving the tasks of the rehabilitation of the nuclear legacy. (author)

  14. Implication of Crystal Water Molecules in Inhibitor Binding at ALR2 Active Site

    Directory of Open Access Journals (Sweden)

    Hymavati

    2012-01-01

    Full Text Available Water molecules play a crucial role in mediating the interaction between a ligand and a macromolecule. The solvent environment around such biomolecule controls their structure and plays important role in protein-ligand interactions. An understanding of the nature and role of these water molecules in the active site of a protein could greatly increase the efficiency of rational drug design approaches. We have performed the comparative crystal structure analysis of aldose reductase to understand the role of crystal water in protein-ligand interaction. Molecular dynamics simulation has shown the versatile nature of water molecules in bridge H bonding during interaction. Occupancy and life time of water molecules depend on the type of cocrystallized ligand present in the structure. The information may be useful in rational approach to customize the ligand, and thereby longer occupancy and life time for bridge H-bonding.

  15. Redox activity of airborne particulate matter at different sites in the Los Angeles Basin

    International Nuclear Information System (INIS)

    Cho, Arthur K.; Sioutas, Constantinos; Miguel, Antonio H.; Kumagai, Yoshito; Schmitz, Debra A.; Singh, Manisha; Eiguren-Fernandez, Arantza; Froines, John R.

    2005-01-01

    Epidemiologic studies have shown associations between ambient particulate matter (PM) and adverse health outcomes including increased mortality, emergency room visits, and time lost from school and work. The mechanisms of PM-related health effects are still incompletely understood, but a hypothesis under investigation is that many of the adverse health effects may derive from oxidative stress, initiated by the formation of reactive oxygen species (ROS) within affected cells. While the adverse effects from PM have historically been associated with the airborne concentration of PM and more recently fine-particle PM, we considered it relevant to develop an assay to quantitatively measure the ability of PM to catalyze ROS generation as the initial step in the induction of oxidative stress. This ability of PM could then be related to different sources, chemical composition, and physical and spatial/temporal characteristics in the ambient environment. The measurement of ROS-forming ability in relation to sources and other factors will have potential relevance to control of redox-active PM. If oxidative stress represents a relevant mechanism of toxicity from PM, the measurement of redox activity represents a first step in the elucidation of the subsequent downstream processes. We have developed an assay for PM redox activity, utilizing the reduction of oxygen by dithiothreitol which serves as an electron source. We have found that PM will catalyze the reduction of oxygen and have examined the distribution and chemical characteristics of the redox activity of PM fractions collected in different sites in the Los Angeles Basin. Samples of concentrated coarse, fine, and ultrafine PM, obtained with aerosol concentrators, were studied with regard to their chemical properties and redox activity. Redox