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51.
Animal production systems convert plant protein into animal protein. Depending on animal species, ration and management, between 5% and 45 % of the nitrogen (N) in plant protein is converted to and deposited in animal protein. The other 55%-95% is excreted via urine and feces, and can be used as nutrient source for plant (= often animal feed) production. The estimated global amount of N voided by animals ranges between 80 and 130 Tg N per year, and is as large as or larger than the global annual N fertilizer consumption. Cattle (60%), sheep (12%) and pigs (6%) have the largest share in animal manure N production. The conversion of plant N into animal N is on average more efficient in poultry and pork production than in dairy production, which is higher than in beef and sheep production. However, differences within a type of animal production system can be as large as differences between types of animal production systems, due to large effects of the genetic potential of animals, animal feed and management. The management of animals and animal feed, together with the genetic potential of the animals, are key factors to a high efficiency of conversion of plant protein into animal protein. The efficiency of the conversion of N from animal manure, following application to land, into plant protein ranges between 0 and 60%, while the estimated global mean is about 15%. The other 40%-100% is lost to the wider environment via NH3 volatilization, denitrification, leaching and run-off in pastures or during storage and/or following application of the animal manure to land. On a global scale, only 40%-50% of the amount of N voided is collected in barns, stables and paddocks, and only half of this amount is recycled to crop land. The N losses from animal manure collected in barns, stables and paddocks depend on the animal manure management system. Relative large losses occur in confined animal feeding operations, as these often lack the land base to utilize the N from animal manure effectively. Losses will be relatively low when all manure are collected rapidly in water-tight and covered basins, and when they are subsequently applied to the land in proper amounts and at the proper time, and using the proper method (low-emission techniques). There is opportunity for improving the N conversion in animal production systems by improving the genetic production potential of the herd, the composition of the animal feed, and the management of the animal manure. Coupling of crop and animal production systems, at least at a regional scale, is one way to high N use efficiency in the whole system. Clustering of confined animal production systems with other intensive agricultural production systems on the basis of concepts from industrial ecology with manure processing is another possible way to improve N use efficiency. 相似文献
52.
53.
GV Pavlova AA Vergun EY Rybalkina PR Butovskaya AP Ryskov 《Cell cycle (Georgetown, Tex.)》2015,14(2):200-205
Random amplified polymorphic DNA (RAPD) analysis was adapted for genomic identification of cell cultures and evaluation of DNA stability in cells of different origin at different culture passages. DNA stability was observed in cultures after no more than 5 passages. Adipose-derived stromal cells demonstrated increased DNA instability. RAPD fragments from different cell lines after different number of passages were cloned and sequenced. The chromosomal localization of these fragments was identified and single-nucleotide variations in RAPD fragments isolated from cell lines after 8–12 passages were revealed. Some of them had permanent localization, while most variations demonstrated random distribution and can be considered as de novo mutations. 相似文献
54.
Abstact Milk and dairy products purchased at Egyptian markets and breast milk from lactating mothers in Cairo and Giza governorates
were analyzed for some mycotoxins. Three of 15 cows’ milk samples were found positive for Afl. M1 with mean value 6.3 ppb. Only one sample of dried milk was positive (5 ppb). Two of 10 hard cheese samples contained detectable
levels of Afl. M1 (3and 6 ppb), whereas one sample containing Afl. B1 and G1 (10 and 4 ppb resp.). For soft cheese one sample of 10 was positive for Afl. M1 (0.5 ppb). Blue veined cheeses were free of Afl. M1 and PR-toxins.
For breast milk two of 10 samples were positive for Afl. M1 (20%) with mean value 2.75 ppb, while 3 of 10 samples were positive for Ochratoxin A (30 %). 相似文献
55.
56.
Background
Monetary incentives are an effective way of increasing response rates to surveys, though they are generally less effective in physicians, and are more effective when the incentive is paid up-front rather than when made conditional on completion. 相似文献57.
Geert Zegels Geert AA Van Raemdonck Wiebren AA Tjalma Xaveer WM Van Ostade 《Proteome science》2010,8(1):63
Cervicovaginal fluid has an important function in the homeostasis and immunity of the lower female genital tract. Analysis
of the cervicovaginal fluid proteome may therefore yield important information about the pathogenesis of numerous gynecological
pathologies. Additionally, cervicovaginal fluid has great potential as a source of biomarkers for these conditions. 相似文献
58.
Lauren Anton David C Merrill Liomar AA Neves Courtney Gruver Cheryl Moorefield K Bridget Brosnihan 《Reproductive biology and endocrinology : RB&E》2010,8(1):135
Background
During preeclampsia, placental angiogenesis is impaired. Factors released from the placenta including vascular endothelial growth factor (VEGF), placental growth factor (PLGF), soluble VEGF receptor 1 (sFlt1), and soluble endoglin (sEng) are regulatory molecules of placental development and function. While the renin angiotensin system has been shown to regulate angiogenic factors in other research fields, these mechanisms have not been extensively studied during pregnancy. 相似文献59.
Zirconyl hematoxylin stains acidic mucins darkly and specifically using a solution of 100 mg hematoxylin, 5 ml ethanol, 5 ml 0.5% sodium iodate, 400 mg zirconyl chloride octahydrate, and 30 ml 25% aqueous glycerol. The stain is especially advantageous for studying goblet cells and Paget cells. 相似文献
60.
Integrated chorda tympani nerve responses to NaCl were studied in two mouse
strains, an NaCl-preferring NZB/B1NJ and an NaCl-avoiding CBA/J. The NaCl
responses of both strains had similar magnitude and were suppressed by
amiloride to a similar extent. This suggests that peripheral gustatory
responsiveness to NaCl is not the only mechanism underlying mouse strain
variation in NaCl acceptance.
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