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51.
52.
Chigerwe M Tyler JW Schultz LG Middleton JR Steevens BJ Spain JN 《American journal of veterinary research》2008,69(9):1158-1163
OBJECTIVE: To determine the amount of colostral IgG required for adequate passive transfer in calves administered colostrum by use of oroesophageal intubation and evaluate the impact of other factors on passive transfer of colostral immunoglobulins in calves. ANIMALS: 120 Holstein bull calves. PROCEDURES: Calves were randomly assigned to specific treatment groups on the basis of volume of colostrum administered and age of calf at administration of colostrum. Colostrum was administered once by oroesophageal intubation. Equal numbers of calves received 1, 2, 3, or 4 L of colostrum, and equal numbers of calves received colostrum at 2, 6, 10, 14, 18, or 22 hours after birth. Serum samples were obtained from calves 48 hours after birth for IgG determination by radial immunodiffusion assay. Effects of factors affecting transfer of colostral immunoglobulins were determined by use of a stepwise multiple regression model and logistic regression models. RESULTS: A minimum of 153 g of colostral IgG was required for optimum colostral transfer of immunoglobulins when calves were fed 3L of colostrum at 2 hours after birth. Substantially larger IgG intakes were required by calves fed colostrum > 2 hours after birth. CONCLUSIONS AND CLINICAL RELEVANCE: Feeding 100 g of colostral IgG by oroesophageal intubation was insufficient for adequate passive transfer of colostral immunoglobulins. At least 150 to 200 g of colostral IgG was required for adequate passive transfer of colostral immunoglobulins. Use of an oroesophageal tube for administration of 3 L of colostrum to calves within 2 hours after birth is recommended. 相似文献
53.
Hannes Dempewolf Loren H. Rieseberg Quentin C. Cronk 《Genetic Resources and Crop Evolution》2008,55(8):1141-1157
Despite current recognition as the largest family of flowering plants (23,000 species ± 1000; Anderberg et al. 2007), the Compositae is home to comparatively few important crop species. To assess domestication levels in the Compositae, we
developed an index that categorizes taxa according to the strength of domestication. Most Compositae species that are used
by humans exhibit little or no evidence of domestication and only a handful have been strongly domesticated. Although the
Compositae (along with Orchidaceae) has few domesticated taxa compared to other large families such as Fabaceae or Poaceae,
Compositae species have features that should make them suitable for domestication and human consumption. These include high
species diversity, global geographic distribution, good seed storability, and good seed oil quality. We propose that the paucity
of domesticated species in this family can be attributed to a variety of factors, chiefly the prevalence of secondary defence
compounds, the lack of carbohydrates that can be digested by the human gut and the predominantly mechanical or wind-dependent
seed dispersal syndrome. We also discuss the relevance of genetic and cultural factors. Although few Compositae crops currently
play a major role in global agriculture, many species hold unexploited potential, especially as novel crops for food and industrial
applications. 相似文献
54.
Summary CertainPhaseolus vulgaris L. ×P. lunatus L. crosses were performed to study the effect of maternal heterozygosity on development and growth of the interspecific hybrid embryos. Interspecific embryos had a much slower growth rate in vitro compared with embryos derived from self-pollination ofP. vulgaris parents. Thus, interspecific embryos could be identified by growth rate in vitro. TheP. vulgaris maternal genotype affected both the number and size of 15-day-old interspecific embryos. Specifically, 76 Spartan Arrow produced significantly more interspecific embryos than did Great Northern as the seed parent, while maternal intraspecific hybrids produced smaller embryos than did maternal pure lines. There were no reciprocal differences between hybrid maternal parents for embryo number or size. Embryo size at excision and final size after culturing were closely correlated (r2=+0.93). The crossP. vulgaris 76 Spartan Arrow ×P. lunatus P.I. 214170 produced both the largest mean size at excision and the fastest growth in culture, indicating that specific combining ability affected both characteristics.Journal Paper No. J-12208 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 2495 相似文献
55.
An x-ray crystal structure that confirms the soccer ball-shaped carbon framework of C(60) (buckminsterfullerene) is reported. An osmyl unit was added to C(60) in order to break its pseudospherical symmetry and give an ordered crystal. The crystal structure of this derivative, C(60)(OsO(4))(4-tert-butylpyridine)(2), reveals atomic positions within the carbon cluster. 相似文献
56.
Chan WL Ligges M Jailaubekov A Kaake L Miaja-Avila L Zhu XY 《Science (New York, N.Y.)》2011,334(6062):1541-1545
Multiple exciton generation (MEG) refers to the creation of two or more electron-hole pairs from the absorption of one photon. Although MEG holds great promise, it has proven challenging to implement, and questions remain about the underlying photo-physical dynamics in nanocrystalline as well as molecular media. Using the model system of pentacene/fullerene bilayers and femtosecond nonlinear spectroscopies, we directly observed the multiexciton (ME) state ensuing from singlet fission (a molecular manifestation of MEG) in pentacene. The data suggest that the state exists in coherent superposition with the singlet populated by optical excitation. We also found that multiple electron transfer from the ME state to the fullerene occurs on a subpicosecond time scale, which is one order of magnitude faster than that from the triplet exciton state. 相似文献
57.
Fong LG Frost D Meta M Qiao X Yang SH Coffinier C Young SG 《Science (New York, N.Y.)》2006,311(5767):1621-1623
Progerias are rare genetic diseases characterized by premature aging. Several progeroid disorders are caused by mutations that lead to the accumulation of a lipid-modified (farnesylated) form of prelamin A, a protein that contributes to the structural scaffolding for the cell nucleus. In progeria, the accumulation of farnesyl-prelamin A disrupts this scaffolding, leading to misshapen nuclei. Previous studies have shown that farnesyltransferase inhibitors (FTIs) reverse this cellular abnormality. We tested the efficacy of an FTI (ABT-100) in Zmpste24-deficient mice, a mouse model of progeria. The FTI-treated mice exhibited improved body weight, grip strength, bone integrity, and percent survival at 20 weeks of age. These results suggest that FTIs may have beneficial effects in humans with progeria. 相似文献
58.
Noe Galvan John R. Middleton Dusty W. Nagy Loren G. Schultz Josh W. Schaeffer 《The Canadian veterinary journal. La revue veterinaire canadienne》2012,53(12):1310-1313
A herd of alpacas was examined because of a history of severe endoparasitism, anemia, hypoproteinemia, and weight loss. Resistance of gastrointestinal nematodes to albendazole, fenbendazole, and doramectin was documented. This report suggests that anthelmintic resistance may be an emerging problem in South American camelids in North America. 相似文献
59.
60.
A painful neuroma occurs following 25% of routine equine neurectomies unless special neurosurgery is done. There are at least five other complications that one may encounter: (1) A change of gait such as stumbling or forging has been noted, especially when the neurectomy has been done in one leg; (2) A vascular compromise has been found if there had been any complications in wound healing or excessive tissue insult. Excessive scar formation surrounding both the digital vein and artery can compromise the blood supply to the foot. When the posteriod digital nerves are severed the autonomic nerves are also interrupted. This results in a vasodilatation which may be responsible for faster hoof growth; (3) If the navicular bone had undergone osteolytic changes before the neurectomy it may fracture as soon as the horse starts to use the foot; (4) The deep flexor tendon may rupture where it passes over the navicular bone. This is especially true where adhesions between the bone and tendon were present; (5) Infections in the sole, bulbs of heel, frog, navicular bursa or coffin joint often go unattended because the horse does not show a lameness. 相似文献