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1.
Plasma vitamin D and vitamin D metabolites were measured in Atlantic salmon parr during smoltification and after transfer to seawater. The fish were fed commercial feed for 5 months under natural light, and Na+/K+ ATPase was measured as an indicator of the smoltification status. No significant differences were recorded in the level of plasma vitamin D metabolites. However, a tendency of increasing plasma concentration of 25OHD3 and also a temporary increase in plasma 1,25(OH)2D3 and 24,25(OH)2D3 were recorded prior to seawater transfer. The minor changes in plasma levels of the metabolites indicate a role of the vitamin D metabolites during parr–smolt transformation, although we do not know whether the increased levels are caused by increased synthesis of the metabolites or by decreased binding to receptors or decreased excretion.  相似文献   
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White fat progenitor cells reside in the adipose vasculature   总被引:1,自引:0,他引:1  
White adipose (fat) tissues regulate metabolism, reproduction, and life span. Adipocytes form throughout life, with the most marked expansion of the lineage occurring during the postnatal period. Adipocytes develop in coordination with the vasculature, but the identity and location of white adipocyte progenitor cells in vivo are unknown. We used genetically marked mice to isolate proliferating and renewing adipogenic progenitors. We found that most adipocytes descend from a pool of these proliferating progenitors that are already committed, either prenatally or early in postnatal life. These progenitors reside in the mural cell compartment of the adipose vasculature, but not in the vasculature of other tissues. Thus, the adipose vasculature appears to function as a progenitor niche and may provide signals for adipocyte development.  相似文献   
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Many fields have struggled to develop strategies, policies, or structures to optimally manage data, materials, and intellectual property rights (IPRs). There is growing recognition that the field of stem cell science, in part because of its complex IPRs landscape and the importance of cell line collections, may require collective action to facilitate basic and translational research. Access to pluripotent stem cell lines and the information associated with them is critical to the progress of stem cell science, but simple notions of access are substantially complicated by shifting boundaries between what is considered information versus material, person versus artifact, and private property versus the public domain.  相似文献   
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Infection with sorbitol-fermenting Shiga toxin-producing Escherichia coli O157:H- (sf STEC O157:H-) is rare, but emerging in Europe. The pathogen is typically isolated from paediatric patients with life-threatening haemolytic uraemic syndrome (HUS). It is unclear whether this observation primarily reflects the pathogen's virulence or its complex laboratory diagnosis, not routinely conducted in diarrhoeal patients. In summer 2009, four boys living in the same suburb in Germany developed diarrhoea-associated HUS: three were infected by sf STEC O157:H- and one died. We conducted two analytical epidemiological studies, an extensive search for diarrhoeal cases in potentially exposed groups, and an environmental investigation. Outbreak cases were residents of the suburb diagnosed with HUS, sf STEC O157:H- infection, or both between 24 July 2009 and 25 August 2009. Overall, we ascertained eight cases with a median age of 4 years (range: from 8 months to 9 years). Stool screening of 220 persons led to the identification of only four additional cases: two asymptomatic carriers and two diarrhoeal cases. HUS was strongly associated with visiting a local playground in July, particularly on 16th July (odds ratio = 42.7, P = 0.002). No other commonality, including food, was identified, and all environmental samples (n = 24) were negative. In this localized non-foodborne outbreak, the place of likely infection was a local playground. Sf STEC O157:H- infection apparently limits itself rarely to diarrhoeal illness and progresses frequently to HUS. Therefore, detection of and response to this hypervirulent pathogen primarily relies on HUS surveillance.  相似文献   
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Manipulation of Domestic Animal Embryos and Implications for Development   总被引:1,自引:0,他引:1  
Assisted reproductive technologies, as applied to domestic animals, can exert both novel and wide‐ranging influences on the development, viability and welfare of offspring. Some of the changes are evident immediately or soon after the time at which a manipulative procedure is carried out, while other changes may not be evident until later in development or, perhaps, may remain undetected throughout an animal's lifetime. The present review explores some of the consequences – in terms of foetal, placental, neonatal and post‐natal effects – of exposing embryos of cattle, sheep and other species to in vitro culture per se or, during culture, to physically invasive technologies including gene injection and nuclear transfer. The innate sensitivity of oocytes and recently fertilized eggs to their in vitro environment is illustrated by an examination of the later developmental repercussions resulting from apparently innocuous choices related to in vitro culture medium formulations. In contrast, an inherent resilience and paradoxical readiness to resume development following the traumas of nuclear transfer procedures is also in evidence. The extent to which assisted reproductive technologies will succeed, where relevant, in the domestic animal sector will be influenced by our appreciation of embryo requirements, for both short‐ and long‐term developmental fitness, during their earliest developmental stages. Evidence of species‐specific needs is testimony to the challenges ahead. Ultimately, our ability and inclination to resolve the limitations associated with current procedures will probably be greatly enhanced if predictive indicators (genetic, epigenetic or functional markers) of later developmental fitness can be identified.  相似文献   
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Flash heating of Illinois coal (to 700 degrees C in 1 second) in flowing hydrogen at 100 atmospheres, limiting the vapor residence time at 700 degrees C to 3 seconds, converts 14 percent of the coal's carbon to methane, 7 percent to ethane, and 10 percent to benzene, toluene, and xylenes. The remainder is coke; the carbon balance shows that heavy tar, if any exists, is less than 3 percent.  相似文献   
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ABSTRACT

Aims: To collect baseline data on the contact risk pathways and biosecurity practices of commercial poultry farms in New Zealand, investigate the relationship between the farm-level disease contact risks and biosecurity practices, and identify important poultry health concerns of producers.

Methods: A cross-sectional survey of all registered New Zealand commercial poultry operations was conducted in 2016 collecting information on farm demographics, biosecurity practices, and contact risk pathways. Survey responses were used to generate an unweighted subjective disease risk score based on eight risk criteria and a subjective biosecurity score based on the frequency with which producers reported implementing seven biosecurity measures. Producer opinions towards poultry health issues were also determined.

Results: Responses to the survey response were obtained from 120/414 (29.0%) producers, including 57/157 (36.3%) broiler, 33/169 (19.5%) layer, 24/55 (44%) breeder, and 6/32 (19%) other poultry production types. Median disease risk scores differed between production types (p?<?0.001) and were lowest for breeder enterprises. The greatest risk for layer and broiler enterprises was from the potential movement of employees between sheds, and for breeder enterprises was the on- and off-farm movement of goods and services. Median biosecurity scores also differed between production types (p?<?0.001), and were highest for breeder and broiler enterprises. Across all sectors there was no statistical correlation between biosecurity scores and disease risk scores. Producers showed a high level of concern over effectively managing biosecurity measures.

Conclusions: The uptake of biosecurity measures in the commercial poultry farms surveyed was highly variable, with some having very low scores despite significant potential disease contact risks. This may be related to the low prevalence or absence of many important infectious poultry diseases in New Zealand leading farmers to believe there is a limited need to maintain good biosecurity as well as farmer uncertainty around the efficacy of different biosecurity measures. Further research is needed to understand barriers towards biosecurity adoption including evaluating the cost-effectiveness of biosecurity interventions.  相似文献   
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