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排序方式: 共有152条查询结果,搜索用时 78 毫秒
61.
Chung KK Thomas B Li X Pletnikova O Troncoso JC Marsh L Dawson VL Dawson TM 《Science (New York, N.Y.)》2004,304(5675):1328-1331
Parkin is an E3 ubiquitin ligase involved in the ubiquitination of proteins that are important in the survival of dopamine neurons in Parkinson's disease (PD). We show that parkin is S-nitrosylated in vitro, as well as in vivo in a mouse model of PD and in brains of patients with PD and diffuse Lewy body disease. Moreover, S-nitrosylation inhibits parkin's ubiquitin E3 ligase activity and its protective function. The inhibition of parkin's ubiquitin E3 ligase activity by S-nitrosylation could contribute to the degenerative process in these disorders by impairing the ubiquitination of parkin substrates. 相似文献
62.
BACKGROUND: Systemicity is an important attribute of fungicides that is difficult to measure in early‐stage screening without labeling the compound with a radioisotope. A method of measuring translocation that does not require potent fungicidal activity or a radiolabel would guide identification of compounds with desirable attributes. RESULTS: The authors developed an analytical technique that mimics field application, using LC‐MS/MS to screen compounds for translocation in wheat leaves. The method sorted commercial and experimental fungicides appropriately into systemic and non‐systemic categories. A model using LC‐MS/MS data was equivalent to a lipophilicity model and superior to a water solubility model at predicting compound systemicity. CONCLUSION: Early‐stage compounds can be screened for systemicity on whole plants using LC‐MS/MS. Copyright © 2008 Society of Chemical Industry 相似文献
63.
Yubin Yang Lloyd Ted WilsonJing Wang Xiaobao Li 《Computers and Electronics in Agriculture》2011,76(1):105-118
Most cropping system models and decision support tools are structured for site-specific (i.e. field- or point-based) simulation and analysis. As the need grows for analyses on crop production and management at local, county, state, national, and even global scales, cropping system models and decision support tools are increasingly structured to provide the capability for area-wide simulation and analysis at a range of spatial scales. A major challenge is the development of a data management system that can provide dynamic access to large volumes of geo-referenced data needed by such applications. The objective of this paper is to present a methodology to develop a Cropland and Soil Data Management system that is capable of automatic data consolidation and integration, and can provide dynamic access to the integrated data by cropping system applications. The Cropland Data Management component of the system is based on the Cropland Data Layer (CDL) products from the USDA National Agricultural Statistics Service and is implemented with seven program modules: Data Requester, Data Fetcher, Data Parser, Geodatabase Builder, Map Service Builder, Map Cache Generator, and Cropland Map Viewer. The Soil Data Management component is based on the Soil Survey Geographic (SSURGO) database from the USDA Natural Resources Conservation Service and is implemented with six program modules: Data Requester, Data Fetcher, Data Parser, Database Builder, Soil Map Generator, and Soil Map Viewer. The approaches and methodology presented in the paper can serve as a reference for those who are interested in developing integrated cropping system applications. 相似文献
64.
Robert F. Polomski Milton D. Taylor Douglas G. Bielenberg William C. Bridges Stephen J. Klaine Ted Whitwell 《Water, air, and soil pollution》2009,197(1-4):223-232
In the greenhouse and container nursery production industry there is potential for runoff of nitrogen (N) and phosphorus (P), which may contaminate surface and groundwater. Since the 1950s constructed wetlands (CWs), as a simple, low-technology method, have been shown to effectively treat agricultural, industrial, and municipal wastewater. We investigated the N and P attenuating potential of three floating hydrophytes planted in a laboratory-scale subsurface flow (SSF) CW system. Over an 8-week period plants were supplied with N and P (0.39 to 36.81 mg·L?1 N and 0.07 to 6.77 mg·L?1 P) that spanned the rates detected in nursery runoff between the discharge and inflow locations of a commercial nursery currently employing CWs. Whole plant dry weight was positively correlated with N and P supplied. Highest N recovery rates were exhibited by water hyacinth (Eichhornia crassipes [Mart.] Solms.) and water lettuce (Pistia stratiotes L.). P recovery rates were similar for water hyacinth, water lettuce, and dwarf redstemmed parrotfeather (Myriophyllum aquaticum [Vell.] Verdc.). These floating hydrophytes can be cultivated in a SSF CW to remediate runoff losses of N and P. The possibility exists for integrating them into a polycultural remediation system that includes emergent aquatic macrophytes for processing and polishing nursery/greenhouse wastewater. 相似文献
65.
Ferré PJ Pasloske K Whittem T Ranasinghe MG Li Q Lefebvre HP 《Veterinary anaesthesia and analgesia》2006,33(4):229-236
OBJECTIVE: To determine the pharmacokinetic parameters of alfaxalone in dogs after the intravenous (IV) administration of clinical and supra-clinical doses of a 2-hydroxypropyl-beta-cyclodextrin (HPCD) alfaxalone formulation (Alfaxan-CD RTU). EXPERIMENTAL DESIGN: Prospective two-period crossover design. Animals Eight (four male and four female) young adult healthy Beagle dogs. Methods The steroid anaesthetic alfaxalone was administered IV at two doses in a crossover design (2 and 10 mg kg(-1)) with a washout period of 21 days. Blood samples were collected before and up to 8 hours after dosing. Plasma concentrations of alfaxalone were assayed using a liquid chromatograph/mass selective detector technique and analyzed to estimate the main pharmacokinetic parameters by noncompartmental analysis. Results were expressed as mean +/- SD. RESULTS: The mean duration of anaesthesia from endotracheal intubation to extubation was 6.4 +/- 2.9 and 26.2 +/- 7.5 minutes, for the 2 and 10 mg kg(-1) doses, respectively. The plasma clearance of alfaxalone for the 2 and 10 mg kg(-1) doses differed statistically at 59.4 +/- 12.9 and 52.9 +/- 12.8 mL kg(-1) minute(-1), respectively (p = 0.008) but this difference was deemed clinically unimportant; the harmonic mean plasma terminal half-lives (t(1/2)) were 24.0 +/- 1.9 and 37.4 +/- 1.6 minutes respectively. The volume of distribution was between 2 and 3 L kg(-1) and did not differ between the two doses. No sex effect was observed. CONCLUSIONS AND CLINICAL RELEVANCE: Alfaxalone, as an HPCD formulation (Alfaxan-CD RTU) administered in the dog provides rapid and smooth induction of anaesthesia, satisfactory conditions for endotracheal intubation and a short duration of anaesthesia. There was no clinically significant modification of the pharmacokinetic parameters between sexes and between the clinical (2 mg kg(-1)) and supra-clinical (10 mg kg(-1)) doses. 相似文献
66.
67.
Influences of irrigation,nitrogen and zeolite management on the physicochemical properties of rice 总被引:1,自引:0,他引:1
Taotao Chen Lloyd Ted Wilson Qian Liang Wei Chen 《Archives of Agronomy and Soil Science》2017,63(9):1210-1226
The addition of zeolite (Z) to soils is increasingly being recognised as a way to enhance agricultural production and decrease fertilisation requirements and, hence, environmental costs. Meanwhile, the alternate wetting and drying irrigation (AWD) has become widely applied to reduce the water requirements of rice cultivation. However, limited information is available on their impacts on rice’s physicochemical properties. This study investigated an integrated irrigation, nitrogen (N) and Z rice production system and assessed its effects on the milling, appearance, nutrition, taste and cooking qualities of the rice grain produced. Compared with conventional flooding irrigation (CF), AWD-grown rice had slightly decreased milling and appearance qualities. Addition of Z increased rice protein content and slightly decreased eating quality without affecting milling, appearance and cooking qualities. The highest yields achieved under AWD (9.8 t ha?1) and CF (8.9 t ha?1) were achieved using 105 kg N and 10 t Z ha?1, and 105 kg N and 5 t Z ha?1, respectively. Compared with the flooding untreated control (using 157.5 kg N ha?1 and no Z), these two treatment regimens required 27.8% and 8.1% less water, 33.3% less N fertiliser and increased yields by 10.6% and 0.6%, respectively, without measurably affecting rice grain quality. 相似文献
68.
Min B. Rayamajhi Paul D. Pratt Ted D. Center Thai K. Van 《European Journal of Forest Research》2010,129(6):1155-1168
The exotic tree Melaleuca quinquenervia (melaleuca) forms dense forests usually characterized by low plant diversities and dense litter biomass accumulations on
forest floors of ecologically sensitive ecosystems, including portions of the Florida Everglades. We quantified litter accumulation
in mature melaleuca stands and compared decomposition rates of melaleuca leaves with a sympatric native plant, either Cladium jamaicense (sawgrass) in sawgrass marshes or Pinus
elliottii (slash pine) in pine flatwoods habitats that varied in soil types. Total litter accumulation in mature melaleuca forests
prior to June 1997 ranged from 12.27 to 25.63 Mg ha−1. Overall, melaleuca leaves decomposed faster in organically rich versus arenaceous soils. Decomposition rates were lower
for melaleuca leaves than for sawgrass in both melaleuca-invaded and uninvaded sawgrass marshes. In arenaceous soils of pine
flatwoods, melaleuca leaf and pine needle decomposition rates were similar. Complete mineralization of sawgrass leaves occurred
after 258 weeks, whereas melaleuca leaves had up to 14% and pine foliage had up to 19% of the original biomass remaining after
322 weeks. Total carbon (C) in intact decomposing leaves varied slightly, but total nitrogen (N) steadily increased for all
three species; the greatest being a fourfold in sawgrass. Increases in N concentrations caused decreases in the C/N ratios
of all species but remained within an optimal range (20–30) in sawgrass resulting in higher decomposition rates compared to
melaleuca leaves and pine needles (C/N ratio >30). Slower decomposition of melaleuca leaves results in denser litter layers
that may negatively affect recruitment of other plant species and impede their establishment in invaded communities. 相似文献
69.
Moisture-induced protein aggregation in a dry or intermediate-moisture food matrix can contribute to the loss of product acceptability. The present study evaluated the molecular mechanisms and controlling factors for moisture-induced whey protein aggregation in a premixed protein/buffer model system. Insoluble aggregates rapidly formed during the first 3 days of storage at 35 degrees C with a slower rate afterward. Evaluation of the insoluble aggregates by solubility tests in solutions containing SDS/urea/guanidine HCl/dithiothreitol and gel electrophoresis showed that the formation of intermolecular disulfide bonds was the main mechanism for protein aggregation, and all major whey proteins were involved in the formation of insoluble aggregates. Effects of various factors on aggregation were also investigated, including moisture content, medium pH, and the addition of NaCl. The dependence of aggregation on moisture content was bell-shaped, and the maximal extent of aggregation was achieved at a moisture content of around 70-80% on a dry weight basis. 相似文献
70.
Spatial distribution of soil nutrient at depth in black soil of Northeast China: a case study of soil available phosphorus and total phosphorus 总被引:2,自引:0,他引:2
Shaoliang Zhang Ted Huffman Xingyi Zhang Wei Liu Zhihua Liu 《Journal of Soils and Sediments》2014,14(11):1775-1789