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51.
Effects of supplementation of medium with different antioxidants during in vitro maturation of bovine oocytes on subsequent embryo production 下载免费PDF全文
TC Sovernigo PR Adona PS Monzani S Guemra FDA Barros FG Lopes CLV Leal 《Reproduction in domestic animals》2017,52(4):561-569
The aim of this study was to assess the effects of different antioxidants on the levels of reactive oxygen species (ROS) and glutathione (GSH) in oocytes during in vitro maturation (IVM), as well as on the production of embryos. Oocyte of slaughterhouse‐derived cattle ovaries were placed in IVM with different antioxidants: quercetin (2 μM), cysteamine (100 μM), carnitine (0.5 mg/ml), vitamin C (50 μg/ml) or resveratrol (2 μM). Oocytes matured without any antioxidant supplementation were used as control. The oocytes were assessed for maturation rates and for ROS and GSH levels by fluorescence staining in 2′,7′‐dichlorodihydrofluorescein diacetate and Cell Tracker Blue, respectively. Embryo production was assessed in terms of cleavage, blastocysts and hatching rates and embryo cell numbers. The results expressed in arbitrary fluorescence units showed ROS reduction (p < .05) in the groups with quercetin (27.5 ± 3.4), vitamin C (27.1 ± 3.0) or resveratrol (28.1 ± 4.7), in comparison with those with cysteamine (34.9 ± 4.5), carnitine (34.6 ± 3.8) or to the control group (36.5 ± 5.2). GSH levels increased (p < .05) in cysteamine (63.5 ± 5.5) or carnitine (60.8 ± 4.4) groups in comparison with quercetin (52.7 ± 5.1), vitamin C (53.0 ± 3.8), resveratrol (53.1 ± 4.4) or to the control (49.6 ± 4.5). Nuclear maturation cleavage and hatched blastocysts rates did not differ (p > .05) between groups. However, blastocyst rates after in vitro fertilization in quercetin (53.5 ± 3.9%), vitamin C (52.1 ± 3.1%) resveratrol (54.2 ± 4.0%), cysteamine (52.4 ± 2.7%) or carnitine (54.2 ± 3.1%) groups were higher (p < .05) than in the control (47.2 ± 2.7%). Total cell numbers in embryos from the vitamin C, resveratrol, cysteamine or carnitine groups were higher than in quercetin and control groups, which were similar to each other. The results suggest that using antioxidants during IVM may reduce oxidative stress either by decreasing ROS levels directly or by increasing GSH levels in oocytes, depending on the type of antioxidant used. Overall, oxidative stress control during IVM with the antioxidants examined here improved blastocyst development with similar efficacy. 相似文献
52.
Combined surgical and radiotherapy treatment of a mandibular ameloblastic carcinoma in a pony 下载免费PDF全文
R. J. M. Reardon P. M. Dixon J. Kane‐Smyth T. Froydenlund S. A. Booth J. Dobson K. Smith 《Equine Veterinary Education》2017,29(12):641-646
A 9‐year‐old Welsh Section D gelding was referred to an equine hospital for evaluation and computed tomographic (CT) imaging of a left mandibular swelling. An expansile mass, found within the left mandible at the level of the caudal 2 cheek teeth, was surgically debulked and histology of the lesion identified it as an ameloblastic carcinoma. Radiotherapy using 4 fractions of 800 cGy, 7 days apart, was subsequently undertaken. The pony made excellent clinical progression following treatment. Repeat CT imaging at 7.5 and 19.5 months post surgery showed no apparent recurrence of the lesion and marked improvement in the remodelling of the mandible. In conclusion, radiotherapy in conjunction with surgical debulking appears to have been successful in treating an ameloblastic carcinoma in this pony and could be considered for similar tumours in other cases. 相似文献
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56.
Nitrogen fertilization during planting and establishment of the urban forest: A collection of five studies 总被引:1,自引:0,他引:1
Today's urban forest increasingly consists of planted trees, especially as native forest fragments yield to urban sprawl. These trees are usually larger (over 2-m tall) than typical reforestation trees and grow very little for the first few years after planting. Stressful urban sites exacerbate this effect and many practitioners hope to shorten the time required to reach environmentally functional size by fertilizing at planting. This is a controversial practice since nitrogen (N) application creates the potential for water quality impairment and effectiveness is uncertain. It is not clear how nitrogen application affects large trees with radically altered root:shoot ratios or how nursery production methods and restrictive sites affect response. In a series of five separate studies, we tested several N rates on ten shade tree species (both field- and container-grown) and transplanted to a range of urban sites, from a relatively undisturbed forest fragment to a highly compacted cutover soil with an absent A horizon. Trunk diameter increase, as an integrative metric of tree biomass accumulation, was followed for up to 4 years on each experiment. Overall, we saw little effect from fertilizing at planting at any rate we tested, regardless of location. Three studies that included leaf analysis with a SPAD-502 chlorophyll meter indicated that neither SPAD meter values or N concentration within leaves was increased by fertilizing at planting, suggesting that the newly planted shade trees took up very little of the applied N. Overall, SPAD-502 readings correlated well with actual leaf N concentration (r=0.692). This group of studies indicates that fertilization at planting does not increase post-transplant growth, even in stressful urban sites and it is therefore not effective at shortening the establishment period of transplanted shade trees. 相似文献
57.
Dehai Zhao Michael Kane Robert Teskey Daniel Markewitz Dale Greene Bruce Borders 《Annals of Forest Science》2014,71(8):843-851
Context
To sustainably manage loblolly pine plantations for bioenergy and carbon sequestration, accurate information is required on the relationships between management regimes and energy, carbon, and nutrient export.Aims
The effects of cultural intensity and planting density were investigated with respect to energy, carbon, and essential nutrients in aboveground biomass of mid-rotation loblolly pine plantations, and the effects of harvesting scenarios on export of nutrients were tested.Methods
Destructive biomass sampling of a 12 years-old loblolly pine culture/density experiment, and analysis of variance were used to assess the effects of cultural intensity (operational vs. intensive) and six planting densities ranging from 741 to 4,448 trees ha?1. Two harvesting scenarios (stem-only vs. whole-tree harvesting) were assessed in terms of energy, carbon, and nutrient export.Results
The concentrations of energy, carbon, and nutrients varied significantly among stem wood, bark, branch, and foliage components. Cultural intensity and planting density did not significantly affect these concentrations. Differences in energy, carbon and nutrient contents among treatments were mainly mediated by changes in total biomass. Nutrient contents were affected by either cultural intensity or planting density, or both. Stem-only harvesting removed 71–79 % of aboveground energy and carbon, 29–45 % of N, 28–44 % of P, 44–57 % of K, 51–65 % of Ca, and 50–61 % of Mg.Conclusions
Stem-only harvesting would be preferred to whole-tree harvesting, from a site nutrient conservation perspective. 相似文献58.
59.
P F Kane 《Journal of the Association of Official Analytical Chemists》1986,69(4):664-666
The official AOAC manual Kjeldahl methods for determining crude protein in animal feeds have several disadvantages. For the HgO catalyst method, there are environmental concerns and a lengthy digestion. For the CuSO4 catalyst method, the digestion period is shorter, but still 90 min. A different catalyst combination, CuSO4-TiO2, makes 40 min digestion feasible. Comparison of these catalysts on a group of representative feeds resulted in a mean difference, Cu-Ti minus HgO, of 0.034% protein. Standard deviation of the differences was 0.36. A Student's t-test showed no significant difference. The method will be collaboratively studied. 相似文献
60.
The mesospheric sodium and iron layers at an altitude between about 80 and 110 kilometers are routinely monitored by atmospheric physicists using resonance fluorescence lidar techniques because these constituents are excellent tracers of mesopause chemistry and dynamics. The mesospheric metals are the products of meteoric ablation. Existing ablation profiles are model calculations based in part on radar observations of the ionized background atmosphere left in the wake of high-speed (> 20 kilometers per second) meteoroids. Thin trails of neutral metal atoms, ablated from individual meteoroids, are occasionally observed with high-power lidars. The vertical distribution of 101 sodium and 5 iron meteor trails observed during the past 4 years at Urbana, Illinois; Arecibo, Puerto Rico; and near Hawaii is approximately Gaussian in shape with a centroid height of 89.0 (+/- 0.3) kilometers and a root-mean-square width of 3.3 (+/- 0.2) kilometers. This directly measured ablation profile is nearly the same as the mean iron layer profile but is considerably different from existing models and the distribution of ionized meteor trails observed by radars. A lower limit on the influx to the mesopause region from the lidar meteors is approximately 1.6 x 10(3) sodium and 2.7 x 10(4) iron atoms per second per square centimeter, which corresponds to an annual flux of meteoric debris into the mesosphere of about 2.0 (+/-0.6) gigagrams. Because the lidars can detect only the ablation trails left by the larger meteors, the observations suggest that the actual meteoric influx may be larger than the more recently reported values, which range between 16 and 78 gigagrams per year. 相似文献