Safety and efficacy of two sustained-release intrareticular selenium supplements and the associated placental and colostral transfer of selenium in beef cattle     

D T Campbell  J Maas  D W Weber  O R Hedstrom  B B Norman 《American journal of veterinary research》1990,51(5):813-817

One hundred fifty Se-deficient, pregnant, crossbred beef cows were assigned to 1 of 4 treatment groups: group A, Se-deficient control; group B, 1 Se bolus at 0 and 119 days; group C, 1 Se bolus at 0 days; and group D, 2 Se pellets at 0 days. The Se bolus is an osmotic pump designed to release 3 mg of Se/d into the reticulorumen. The Se pellets weight approximately 30 g and contain 10% elemental Se, which is liberated in the reticulorumen. The Se bolus is designed to provide Se supplementation for 120 days and the Se pellets provide supplementation for up to 18 months. Cattle were maintained on Se-deficient pasture or forages prepared from these pastures for the duration of the experiment. Blood samples were collected from cows prior to treatment (time 0) and at 28, 52, 119, and 220 days thereafter and analyzed for blood Se (BSe) concentration. Body weights were recorded at each sampling time. Blood Se concentration of cows from all supplemented groups were significantly (P less than 0.01) higher than control values at all sample dates after treatments began. By the end of the 220-day study, treatment group-B cattle had significantly (P less than 0.01) higher BSe concentrations than any other group. Body weights of treatment groups fluctuated throughout the study, but did not differ (P greater than 0.05) between groups. One cow and 6 calves born to cows during the experimental period died. Necropsy of 5 calves provided no evidence linking these deaths to treatments.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

A RIGHT-TO-LEFT SHUNTING PATENT DUCTUS ARTERIOSUS WITH SECONDARY PULMONARY HYPERTENSION IN A DOG     

Dr. Norman  Ackerman 《Veterinary radiology & ultrasound》1992,33(3):141-144

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Androgenetic response of heterozygous triticale populations using a greenhouse hydroponic system     

Ahmad Arzani  Norman L. Darvey 《Euphytica》2002,127(1):53-60

Production of haploids, followed by chromosome doubling to produce doubled haploids (DH) represents the most rapid means of achieving complete inbreeding. In order to improve the androgenetic responses and maximize the production of green regenerants from selected plants of twenty-five triticale (× Triticosecale, Wittmack) populations (BC₁F₁, TC₁F₁, and F₂) we used a uniform and optimal growth environment for anther donor plants within a greenhouse hydroponic system. Non-orthogonal analysis of deviance showed highly significant differences (p < 0.001) among populations for both induction and regeneration. The overall induction response of the populations was very high with a mean of 50.4 embryoids per 100 anthers plated. Among all tested-populations, M86-6068/TW179//EP80 (TC₁F₁) was the most responsive for both induction and regeneration which could be associated to its Triticum timopheevii cytoplasm. On the other hand, although populations 80465/II83-194 both as BC₁F₁ and F₂ had a high level of induction response, only a few green plants were regenerated. These populations probably possess a partial Secale montanum genome, which could be contributing to the low regeneration ability. In conclusion, the need for optimization of donor plant growth conditions to effectively assess the androgenetic ability of individual populations/lines would be emphasized. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Vitamin D: A cholecalciferol metabolite highly active in promoting intestinal calcium transport   总被引：8，自引：0，他引：8  

J F Myrtle  A W Norman 《Science (New York, N.Y.)》1971,171(966):79-82

A major polar metabolite of cholecalciferol (vitamin D(3)) obtained from chick intestines is over four times as effective as cholecalciferol and over two times as effective as 25-hydroxycholecalciferol in stimulating intestinal calcium transport 24 hours after administration. Following a considerable lag, cholecalciferol and its 25-hydroxy derivative produce a maximum stimulation of the transport response at 24 to 48 hours. The polar intestinal metabolite greatly shortens this lag, stimulating maximum calcium transport by 9 hours. At 9 hours this metabolite is at least 13 times as active as the parent cholecalciferol and as such is a likely candidate for the biologically active form of cholecalciferol in the intestine.  相似文献   

Soviets Disinvited to Join Drilling Program: An invitation to join the international Ocean Drilling Program has been withdrawn because of objections by DOD     

Norman C 《Science (New York, N.Y.)》1987,236(4802):659-660

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Chiral fiber gratings     

Kopp VI  Churikov VM  Singer J  Chao N  Neugroschl D  Genack AZ 《Science (New York, N.Y.)》2004,305(5680):74-75

Chiral gratings with double helix symmetry were produced by twisting glass optical fiber with a noncircular core cross section as it passed through a miniature oven. We observed polarization-selective transmission in chiral fibers with pitches of tens of micrometers. Two modes of optical interaction were differentiated. In chirallong-period gratings, dips in transmission were observed at wavelengths associated with scattering into distinct cladding modes mediated by the chiral grating. In chiral intermediateperiod gratings, a broad scattering band was observed. These gratings can be used to produce sharp or broad polarization-selective filters.  相似文献   

Virus scare halts hormone research   总被引：1，自引：0，他引：1  

C Norman 《Science (New York, N.Y.)》1985,228(4704):1176-1177

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Plasticity of motor behavior in monkeys with crossed forelimb nerves   总被引：1，自引：0，他引：1  

C Brinkman  R Porter  J Norman 《Science (New York, N.Y.)》1983,220(4595):438-440

Monkeys in which nerves innervating the flexor muscles of the forearm and hand (the ulnar or the median nerve) had been surgically cross-united with the nerve innervating the extensor muscles (the radial nerve), and vice versa, showed excellent (ulnar-radial crosses) to moderate (median-radial crosses) control of movement performance after regeneration. Antagonistic movement responses were seen occasionally, but these were corrected almost immediately. Stimulation of the crossed nerves showed that they had innervated the antagonistic muscle groups. The results reveal the capacity of the primate central nervous system to adapt to gross disturbances imposed on the execution of movements by changes in peripheral innervation.  相似文献   

Feeding a hungry world   总被引：2，自引：0，他引：2  

Borlaug N 《Science (New York, N.Y.)》2007,318(5849):359

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Collaborations as an alternative to projects: Cornell experience with university-NGO-Government networking     

Norman Uphoff 《Agriculture and Human Values》1996,13(2):42-51

Given the limitations of the “project” mode of development assistance, and the likelihood that funding will not be as available in the future for financing large development projects as it has in the past, it is appropriate to consider alternative mechanisms for American institutions and professionals to remain engaged in development efforts overseas. One hopes these will be more effective and cost-effective than previous channels of development aid. The “collaboration” is suggested here as such a mechanism. It involves a US university with overseas universities, government agencies, and nongovernmental organizations (NGOs) in interdisciplinary problem solving, with sustainable agricultural and rural development as the goal, requiring relatively modest levels of funding. There are also benefits to the US institution as it becomes more current and knowledgeable about development problems and opportunities, and better able to provide relevant teaching and research. New partnerships supported by private funding can usefully complement larger-scale official efforts and can fill in gaps where flexible operations relying on the quality of ideas and strong personal relationships offer high returns.  相似文献