排序方式： 共有36条查询结果，搜索用时 234 毫秒
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Jen JC Chan WM Bosley TM Wan J Carr JR Rüb U Shattuck D Salamon G Kudo LC Ou J Lin DD Salih MA Kansu T Al Dhalaan H Al Zayed Z MacDonald DB Stigsby B Plaitakis A Dretakis EK Gottlob I Pieh C Traboulsi EI Wang Q Wang L Andrews C Yamada K Demer JL Karim S Alger JR Geschwind DH Deller T Sicotte NL Nelson SF Baloh RW Engle EC 《Science (New York, N.Y.)》2004,304(5676):1509-1513
The mechanisms controlling axon guidance are of fundamental importance in understanding brain development. Growing corticospinal and somatosensory axons cross the midline in the medulla to reach their targets and thus form the basis of contralateral motor control and sensory input. The motor and sensory projections appeared uncrossed in patients with horizontal gaze palsy with progressive scoliosis (HGPPS). In patients affected with HGPPS, we identified mutations in the ROBO3 gene, which shares homology with roundabout genes important in axon guidance in developing Drosophila, zebrafish, and mouse. Like its murine homolog Rig1/Robo3, but unlike other Robo proteins, ROBO3 is required for hindbrain axon midline crossing. 相似文献
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Bashar W. Shaheen Chengming Wang Calvin M. Johnson Bernhard Kaltenboeck Dawn M. Boothe 《Veterinary microbiology》2009,139(3-4):379-385
Fluoroquinolones are used to treat infections caused by Escherichia coli in canine and feline veterinary patients, particularly those infecting the urinary tract. The gyrA gene is a primary target causing fluoroquinolone resistance in Gram negative coliforms, with mutations in codons 83 and 87 generally associated with high-level of resistance E. coli clinical isolates. We have developed a fluorescence resonance energy transfer (FRET) quantitative PCR to identify enrofloxacin-resistance in clinical E. coli isolates that carry mutations in codons 83 and 87 of gyrA. This real-time quantitative PCR assay is rapid, economical, and sensitive compared with cultured antimicrobial susceptibility testing. The assay identified as few as four genome copies per reaction from culture and 19 genome copies in urine. For the 70 isolates tested, the sensitivity was 87.5% (95% CI = 75–95.3%) (n = 42/48), specificity was 100% (95% CI = 87.3–100%) (n = 22/22), whereas accuracy was 91.4% (95% CI = 82.3–97%) (n = 64/70). Furthermore, we were able to accurately differentiate between the wild type and mutants E. coli directly from infected canine urine samples (n = 5) within 2 h. These results were confirmed by sequence alignments of the PCR products and comparison with the susceptibility testing. The FRET-PCR assay appears to have promising clinical application as an early diagnostic tool for rapid and sensitive detection and differentiation of the level of fluoroquinolone resistance among clinical E. coli isolates that may facilitate design of the dosing regimen. 相似文献
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Rahman Naeem Ur Mehmood Shahid Ahmad Sohail Javid Arshad Mahmud Athar Hussain Jibran Shaheen Muhammad Shabir Usman Muhammad Mohayud Din Hashmi Syed Ghulam 《Tropical animal health and production》2020,52(3):1125-1131
Tropical Animal Health and Production - This study examined the analysis of personal and production performance of broiler farming in 10 cities of central Punjab (Lahore, Sheikhupura, Kasur, Okara,... 相似文献
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Glynn Mitchell Eric D. Clarke Stuart M. Ridley Daren T. Greenhow Kevin J. Gillen Shaheen K. Vohra Peter Wardman 《Pest management science》1995,44(1):49-58
A series of 1,3,4(2H)-isoquinolinetriones have been found to be fast-acting post-emergence herbicides, producing symptoms of desiccation. These redox-active compounds are very potent stimulators of the light-dependent consumption of oxygen at photosystem I in isolated chloroplasts. Pulse radiolysis studies on 2-ethyl-1,3,4(2H)-isoquinolinetrione have shown it to have free-radical properties which could enhance the generation of superoxide radicals in plants. Electrochemical studies further support a redox mediator mode of action for the series. The compounds were found to be unstable towards hydrolysis, and this was considered to be a major factor limiting the overall herbicidal effects. Other parameters, related to uptake and/or translocation, which may limit the full expression of the herbicidal activity of certain compounds, are discussed. 相似文献
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As socio‐environmental problems have proliferated over the past decades, one narrative which has captured the attention of policymakers and scientists has been the need for collaborative research that spans traditional boundaries. Collaboration, it is argued, is imperative for solving these problems. Understanding how collaboration is occurring in practice is important, however, and may help explain the idea space across a field. In an effort to make sense of the shape of fisheries science, here we construct a co‐authorship network of the field, from a data set comprising 73,240 scientific articles, drawn from 50 journals and published between 2000 and 2017. Using a combination of social network analysis and machine learning, the work first maps the global structure of scientific collaboration amongst fisheries scientists at the author, country and institutional levels. Second, it uncovers the hidden subgroups—here country clusters and communities of authors—within the network, detailing also the topical focus, publication outlets and relative impact of the largest fisheries science communities. We find that whilst the fisheries science network is becoming more geographically extensive, it is simultaneously becoming more intensive. The uncovered network exhibits characteristics suggestive of a thin style of collaboration, and groupings that are more regional than they are global. Although likely shaped by an array of overlapping micro‐ and macro‐level factors, the analysis reveals a number of political–economic patterns that merit reflection by both fisheries scientists and policymakers. 相似文献
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B.W. Shaheen D.M. Boothe O.A. Oyarzabal T. Smaha 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2010,24(2):323-330
Background: Antimicrobial resistance is increasing among Escherichia coli isolates associated with spontaneous infection in dogs and cats. Objectives: To describe E. coli resistance phenotypes and clonal relatedness and their regional prevalence. Animals: Isolates of E. coli (n = 376) collected from dogs and cats in the United States between May and September 2005. Methods: Isolates submitted from the South, West, Northeast, and Midwest regions of the United States were prospectively studied. Phenotype was based on E‐test susceptibility to 7 antimicrobials. Isolates were classified as no (NDR), single (SDR), or multidrug resistance (MDR). Clonal relatedness was determined by pulsed‐field gel electrophoresis (PFGE). Results: One hundred and ninety‐three (51%) isolates expressed resistance to at least 1 drug, yielding 42 phenotypes. SDR isolates (n = 84; 44%, 8 phenotypes), expressed resistance most commonly to amoxicillin (30%, n = 25) and least commonly to cefpodoxime (1%, n = 1). MDR isolates (n = 109; 56%, 31 phenotypes) were resistant to amoxicillin (96%, n = 105), amoxicillin‐clavulanate (85%, n = 93), and enrofloxacin (64%, n = 70); 18% (n = 20) were resistant to all drugs tested. The frequency of MDR did not differ regionally (P= .066). MDR minimum inhibitory concentrations (MICs) were 6‐fold higher than SDR MICs (P < .0001). Dendrograms of 91 isolates representing 25 phenotypes revealed 62 different PFGE profiles. Conclusions and Clinical Importance: E. coli strains spontaneously infecting dogs and cats are genetically and phenotypically diverse. Given the current prevalence of MDR among clinical isolates of E. coli in United States, implementation of a robust surveillance program is warranted. 相似文献
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Mohamed Elamir F. Hegazy Tarik A. Mohamed Montaser A. Alhammady Alaa M. Shaheen Eman H. Reda Abdelsamed I. Elshamy Mina Aziz Paul W. Paré 《Marine drugs》2015,13(5):3154-3181
Marine invertebrates including sponges, soft coral, tunicates, mollusks and bryozoan have proved to be a prolific source of bioactive natural products. Among marine-derived metabolites, terpenoids have provided a vast array of molecular architectures. These isoprenoid-derived metabolites also exhibit highly specialized biological activities ranging from nerve regeneration to blood-sugar regulation. As a result, intense research activity has been devoted to characterizing invertebrate terpenes from both a chemical and biological standpoint. This review focuses on the chemistry and biology of terpene metabolites isolated from the Red Sea ecosystem, a unique marine biome with one of the highest levels of biodiversity and specifically rich in invertebrate species. 相似文献