Failure of bone marrow cells to transdifferentiate into neural cells in vivo     

Castro RF  Jackson KA  Goodell MA  Robertson CS  Liu H  Shine HD 《Science (New York, N.Y.)》2002,297(5585):1299

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How farmers matter in shaping agricultural technologies: social and structural characteristics of wheat growers and wheat varieties     

Leland L. Glenna  Raymond A. JussaumeJr.  Julie C. Dawson 《Agriculture and Human Values》2011,28(2):213-224

Science and technology studies (STS) research challenges the concept of technological determinism by investigating how the end users of a technology influence that technology’s trajectory. STS critiques of determinism are needed in studies of agricultural technology. However, we contend that focusing on the agency of end users may mask the role of political-economic factors which influence technology developments and applications. This paper seeks to mesh STS insights with political-economic perspectives by accounting for relationships between availability of diverse technologies, variations in political-economic structures, and farmer interests and characteristics. We present the results of an analysis on the recent development of three wheat varieties: (a) a wheat variety that was modified genetically to tolerate the herbicide glyphosate, (b) wheat varieties with characteristics selected to serve specific markets, (c) and emerging research and development of perennial wheat varieties. Using data obtained through a survey of wheat growers in Washington State, we analyzed whether farmer interest in these three clusters of wheat varieties was associated with distinct individual characteristics and attitudes and whether those characteristics and attitudes are consistent with political economic structures. Although our analysis did not allow us to assess the degree of direct influence that farmers have on the technological development trajectory for these types of wheat, we were able to document variation in technological alternatives and farmer characteristics related to different political-economic trends.  相似文献   

Thermohaline fine structure in an oceanographic front from seismic reflection profiling   总被引：13，自引：0，他引：13  

Holbrook WS  Páramo P  Pearse S  Schmitt RW 《Science (New York, N.Y.)》2003,301(5634):821-824

We present acoustic images of oceanic thermohaline structure created from marine seismic reflection profiles across the major oceanographic front between the Labrador Current and the North Atlantic Current. The images show that distinct water masses can be mapped, and their internal structure imaged, using low-frequency acoustic reflections from sound speed contrasts at interfaces across which temperature changes. The warm/cold front is characterized by east-dipping reflections generated by thermohaline intrusions in the uppermost 1000 meters of the ocean. Our results imply that marine seismic reflection techniques can provide excellent spatial resolution of important oceanic phenomena, including thermohaline intrusions, internal waves, and eddies.  相似文献   

Development of transgenic fungi that kill human malaria parasites in mosquitoes     

Fang W  Vega-Rodríguez J  Ghosh AK  Jacobs-Lorena M  Kang A  St Leger RJ 《Science (New York, N.Y.)》2011,331(6020):1074-1077

Metarhizium anisopliae infects mosquitoes through the cuticle and proliferates in the hemolymph. To allow M. anisopliae to combat malaria in mosquitoes with advanced malaria infections, we produced recombinant strains expressing molecules that target sporozoites as they travel through the hemolymph to the salivary glands. Eleven days after a Plasmodium-infected blood meal, mosquitoes were treated with M. anisopliae expressing salivary gland and midgut peptide 1 (SM1), which blocks attachment of sporozoites to salivary glands; a single-chain antibody that agglutinates sporozoites; or scorpine, which is an antimicrobial toxin. These reduced sporozoite counts by 71%, 85%, and 90%, respectively. M. anisopliae expressing scorpine and an [SM1](8):scorpine fusion protein reduced sporozoite counts by 98%, suggesting that Metarhizium-mediated inhibition of Plasmodium development could be a powerful weapon for combating malaria.  相似文献   

Competencies: a cure for pre-med curriculum     

Anderson WA  Amasino RM  Ares M  Banerjee U  Bartel B  Corces VG  Drennan CL  Elgin SC  Epstein IR  Fanning E  Guillette LJ  Handelsman J  Hatfull GF  Hoy RR  Kelley D  Leinwand LA  Losick R  Lu Y  Lynn DG  Neuhauser C  O'Dowd DK  Olivera T  Pevzner P  Richards-Kortum RR  Rine J  Sah RL  Strobel SA  Walker GC  Walt DR  Warner IM  Wessler S  Willard HF  Zare RN 《Science (New York, N.Y.)》2011,334(6057):760-761

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Presumed immune‐mediated hemolytic anemia in two foals with Rhodococcus equi infection     

Imogen C. Johns BVSc  DACVIM  Anne Desrochers DVM  DACVIM  Kathryn L. Wotman DVM  DACVIM  Raymond W. Sweeney VMD  DACVIM 《Journal of Veterinary Emergency and Critical Care》2011,21(3):273-278

Objective – To describe the clinical presentation, case management, and outcome in 2 foals with Rhodococcus equi infection associated with presumptive severe immune‐mediated hemolytic anemia. Series Summary – Two foals diagnosed with R. equi pneumonia on the basis of tracheal wash cultures, thoracic radiographs, and thoracic ultrasonography were concurrently diagnosed with hemolytic anemia. Both foals required whole blood transfusions, and were treated with the antimicrobial combination of rifampin and a macrolide (eg, clarithromycin, erythromycin, or azithromycin). Dexamethasone was used to prevent further hemolysis in both foals, and to treat acute lung injury/acute respiratory distress syndrome in 1 of the foals. Both foals survived, and required prolonged antimicrobial therapy. New or Unique Information Provided – Although extra‐pulmonary disorders are commonly diagnosed in foals infected with R. equi, hemolytic anemia is rarely described. Dexamethasone is considered the treatment of choice for immune‐mediated hemolytic anemia, but may be contra‐indicated in foals with severe bacterial infections. In these foals, a relatively low dose and short duration of dexamethasone was utilized in an attempt to minimize immune suppression, although early discontinuation in 1 foal precipitated a second hemolytic crisis.  相似文献   

Buffer capacity and lead retention in some clay materials     

Raymond N. Yong  Benno P. Warkentin  Yuwaree Phadungchewit  Rosa Galvez 《Water, air, and soil pollution》1990,53(1-2):53-67

The link between buffer capacity and the ability of clays to retain Pb in interactions between Pb contaminant leachate and the clays, has been studied, using a natural clay from Quebec and laboratory-prepared clays (kaolinite, illite, and smectite). The retention of Pb in the clay suspensions as they received increasing amounts of acid was investigated, and the results examined in terms of the buffer capacity of the clays. As the clays receive increasing amounts of acid (e.g. akin to addition of acid leachate), high amounts of Pb can be retained if the buffer capacity prevents the pH from dropping to values where precipitation mechanisms are not operative. The high carbonate content in the illite gave it a higher buffer capacity than the smectite and natural clay, and permitted it to retain high amounts of Ph. High Pb uptake by the clays can affect the buffer capacity and the Pb retention capacity.  相似文献   

Statistical analysis of interactive cytotoxicity in human epidermal keratinocytes following exposure to a mixture of four metals     

Chris Gennings  Walter H. Carter  Julie A. Campain  Dong-soon Bae  Raymond S. H. Yang 《Journal of Agricultural, Biological & Environmental Statistics》2002,7(1):58-73

Exposure to mixtures of chemicals is an important and relevant environmental issue. Of particular interest is the detection and characterization of departure of biological effects from additivity. Methodology based on the assumption of additivity is used in fitting single-chemicaldata. Interactionsare determined and characterized by making comparisons between the observed and predicted responses at mixtures along a fixed ratio ray of the component substances. Two simultaneous tests are developed for testing for any departure from additivity. Multiple comparisons procedures are used to compare observed responses to that predicted under additivity. A simultaneous confidence band on the predicted responses along the mixture ray is also developed. The methods are illustrated with cytotoxicity data that arise when human epidermal keratinocytes are exposed to a mixture of arsenic, chromium, cadmium, and lead. Synergistic, antagonistic, and additive cytotoxicities were observed at different dose levels of the four-metal mixture.  相似文献   

Kinetics of linuron and metribuzin degradation in soil     

Gillian F. Kempson-Jones  Raymond J. Hance 《Pest management science》1979,10(6):449-454

The disappearance of linuron and metribuzin was studied during laboratory incubation of soil samples which had been taken from several depths at three sites, and treated with the pesticides. Temperature and water content of the soils were varied. There was a tendency for the rate of loss to be slower in soil taken from deeper horizons than in surface soil but the differences were not large. In only ten out of forty experiments did the value 1 for the apparent order of reaction fall within 95% confidence limits. In the remaining experiments the apparent reaction order was greater than 1 with eight values higher than 4. For one soil, the reaction order for linuron was markedly lower for incubation at 22°C compared with incubations at 10°C. The results could be explained on the basis that the systems were complex, involving consecutive or competing reactions. An alternative possibility is that the apparent complexities were artifacts brought about by the inherent limitations of the laboratory incubation system.  相似文献   

Adsorption of glyphosate by soils     

Raymond J. Hance 《Pest management science》1976,7(4):363-366

The adsorption of glyphosate in a slurry system by 9 soils was correlated with an arbitrary single point inorganic phosphate sorption index which gave a measure of unoccupied phosphate sorption capacity, but not with total phosphate sorption capacity at pH 2.6, the level of iron and aluminium soluble in Tamm's acid oxalate or with clay content, organic matter content or pH. It is concluded that inorganic phosphate excludes glyphosate from sorption sites. The extent of adsorption was higher than, though of the same order as, that of diuron though the two are not related. From consideration of the results of previous experiments with plants grown in culture solution it is suggested that the low phytotoxicity of glyphosate applied to the soil is not due simply to high adsorption. Rather it is the result of a combination of moderate adsorption and the low intrinsic activity of this compound when made available to the root system.  相似文献