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Doses of heavy particles at positions inside the command modules of Apollo missions 8, 12, 14, and 16 correlate well with the calculated effects of solar modulation of the primary cosmic radiation. Differences in doses at different stowage positions indicate that the redistribution of mass within the spacecraft could enhance safety from the biological damage that would otherwise be expected on manned, deep-space missions.  相似文献   
14.
The mammalian intestine harbors a beneficial microbiota numbering approximately 10(12) organisms per gram of colonic content. The host tolerates this tremendous bacterial load while maintaining the ability to efficiently respond to pathogenic organisms. In this study, we show that the Bacteroides use a mammalian-like pathway to decorate numerous surface capsular polysaccharides and glycoproteins with l-fucose, an abundant surface molecule of intestinal epithelial cells, resulting in the coordinated expression of this surface molecule by host and symbiont. A Bacteroides mutant deficient in the ability to cover its surface with L-fucose is defective in colonizing the mammalian intestine under competitive conditions.  相似文献   
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SUMMARY Big liver and spleen disease (BLS) was reproduced experimentally by intravenous (IV) and oral (PO) administration of BLS inocula to susceptible broiler breeder hens 34 to 36 weeks of age. Serological and pathological signs of BLS similar to those seen in the natural disease occurred in inoculated and in-contact birds. Splenomegaly was the earliest and often the only necropsy finding, with hepatomegaly and kidney enlargement occurring in some birds later in the course of the disease. After IV administration, serum antigen was detected between 2 and 4 weeks, and antibody between 3 and 5 weeks. After PO administration, antigen was detected between 2 and 4 weeks, and antibody between 3 and 6 weeks. Antibody persisted in all birds to the end of the experiment (6 weeks), and horizontal transmission probably occurred since in-contact birds developed BLS. Liver probably contained the highest concentration of BLS agent because it had the highest infectivity.  相似文献   
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In the voluminous literature on the subject of bGH we have yet to find an attempt to frame the issue in specifically moral terms or to address systematically its ethical implications. I argue that there are two moral objections to the technology: its treatment of animals, and its dislocating effects on farmers. There are agricultural biotechnologies that deserve funding and support. bGH is not one of them.  相似文献   
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SUMMARY To test the hypothesis that joint incongruity contributes to the pathogenesis of elbow osteochondrosis, the left and right radius and ulna of 20 young large breed dogs were measured to determine any variation in length and to observe any incongruity of the elbow joint. Both lame and normal dogs were included in the study. Nine of the 20 dogs had marked disparity in radial and ulnar lengths yet only one had obvious elbow joint incongruity. The use of a sliding osteotomy for the treatment of fragmented coronoid process and a lengthening osteotomy for the treatment of an ununited anconeal process is also discussed. All four dogs treated with a sliding osteotomy showed a marked clinical improvement, and two of the three dogs treated with a lengthening osteotomy showed radiographic fusion of the anconeal process.  相似文献   
18.
SUMMARY: Vascular access ports were surgically placed, first in rabbits maintained under laboratory conditions, and then in koalas maintained in a wildlife park. The ports remained patent for 9 months in rabbits and for up to 13 months in the koalas and were removed successfully. They allowed collection of blood samples without assistance or disturbance in koalas, and without stress as reflected by plasma cortisol concentration. The use of retention rings on the cannula tubing is recommended.  相似文献   
19.
The aim of this work was to examine the influence of the cumulus and gonadotropins on the metabolic profile of porcine cumulus oocyte complexes (COCs) during in vitro maturation. Immature COCs were assigned to morphological classes A1 (with a dense cumulus), A2 (with a translucent cumulus), B1 (with the corona radiata), B2 (with only some remaining cumulus cells) and matured with or without gonadotropins. Glycolysis and ammonia production were higher in the A class COCs; gonadotropins increased both, especially in the A1 COCs (p < 0.05). The A class COCs had the highest initial protein contents and at the end of in vitro maturation. Furthermore, hormonal stimulation induced a similar increase in protein contents of both A classes (p < 0.05). The neutral lipid content and reactive oxygen species (ROS) levels were similar in the immature oocytes of the COCs of all classes. A reduction was seen in both these variables when maturation proceeded either in the presence or absence of gonadotropins. The cumulus type surrounding the oocyte is related to the metabolism of carbohydrates and amino acids by the COC during in vitro maturation under gonadotropic stimulation. Oocyte lipolytic activity and ROS production appear to be independent of the surrounding cumulus and the presence of gonadotropins.  相似文献   
20.
Bronchial-associated immune development is critically important to protect neonates from respiratory infections. Herein, bronchial-associated immune development in formula-fed and sow-reared pigs is described. Colostrum-fed newborn piglets were fed medicated sow milk replacer formula beginning at 48 h of life or remained with the sow. Blood and tissues were sampled at one-week (d7) and three-weeks (d21) of age. Lymphocyte subpopulations, including T helper 2, cytotoxic T, memory T, and NK cells, in peripheral blood, mediastinal lymph nodes, and thoracic lymph nodes were identified using flow cytometry. Additionally, IL-1β, IL-6, IL-12, TNFα, TGF-β1, TGF-β2, IFNα, IFNβ, and dectin gene expression were analyzed by quantitative RT-PCR. Total IgG, IgM, and IgA concentrations in serum were analyzed. Dietary and developmental effects were observed. This set of baseline measurements provides a framework for future respiratory challenge studies where the effects of diet on the neonate's ability to resist and/or recover from infection can be tested.  相似文献   
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