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Hwan Chul Kim Dong Hwan Kim Jacky Park Jong Cheol Lim Young Wan Park 《Fibers and Polymers》2009,10(5):594-600
Epoxy resin containing bromine compound was melt blended with PET to obtain flame retardant polymer. The blend product was
characterized by DSC, SEM, intrinsic viscosity and melt index measurements. The reaction between the epoxy group of DGEBBA
(diglycidyl ether of brominated bisphenol A) and the carboxyl (or hydroxyl) end group of PET led to cross-linking of PET chains,
and the intrinsic viscosity and melt index (MI) were increased in the range of equivalent amount of epoxy resin (within 1
%). DSC data revealed that the epoxy resin was not located in the crystalline region but was appeared in the amorphous region
of PET matrix. Good miscibility of epoxy resin resulted in the decrease of crystallization temperature and glass transition
temperature of PET. The blend was spun into fiber without any problems such as swelling or draw resonance, however, the mechanical
properties were decreased as the amount of the DGEBBA was increased. 相似文献
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A rainfall simulator study of total nutrient movement due to overland flow on forest skid trails and general harvesting areas (GHA) in the native eucalypt forests of southeastern Australia, confirmed that the disturbed and compacted areas were the dominant sources of sediment-bound pollutants. Low runoff production and low sediment availability on the rough surfaces of the GHA reduced total nutrient yields. On the more recently disturbed and burnt sites, the solution pathway may have been more dominant due to runoff coming in contact with surface ash and charcoal. We also recorded significant reductions in the total nutrient yields as runoff from the skid trail was delivered to the adjacent hillslope via a cross bank (water bar). This was due primarily to coarse-grained sediment deposition at the base of the banks. Nutrient concentrations in the eroded sediment at the cross bank outlets, however, remained 9 times higher than the in-situ surface soils, due to the preferential delivery of fine aggregate material to the adjacent hillslope. Further reductions in total nutrient yields occurred as overland flow passed through the GHA, illustrating the effectiveness of vegetative filtering in reducing runoff volumes and sediment fluxes. Temporal trends in the data highlighted significant reductions in total nutrient movement on both areas of disturbance as sites regenerated over a period of ～ 5 years. Water pollution abatement practices in these environments should aim to locate skid trails to maximise the redistribution of runoff and sediment from highly disturbed areas to more vegetated parts of the hillslope, and by appropriate cross bank spacing, reduce the volume of overland flow carrying sediment and nutrients. 相似文献
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对价廉物美的动物产品需要量的增加和现代集约化养殖方式的出现促进了饲料添加剂的应用与发展,包括一些疾病预防性抗生素促生长剂(AGP).在过去的半个世纪里,廉价、具有疾病预防功能的抗生素得到了广泛使用.尽管抗生素的最佳效果的发挥需要依靠以下几个因素:饲养管理、致病菌数、饲养环境应激和日粮配方组成,但是抗生素的使用对提高肉鸡的生长速度与群体整齐度,以及提高饲料报酬上的作用得到养殖户一致的认可. 相似文献
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The motility and fertilizing ability of the Persian sturgeon, Acipenser persicus, spermatozoa were investigated. Optimum ionic content (Na+, K+, Ca2+ and Mg2+) and pH of activation solution as well as the optimum dilution rate were determined. The results show optimum motility characteristics of spermatozoa in buffered solutions containing 25, 0.2, 3 and 10 mM L?1 Na+, K+, Ca2+ and Mg2+, respectively, at dilution rate 1:50 and pH 8.0. To test the fertilizing ability of sperm, two buffered saline solutions were used as activation solution of sperm motility. The present study indicated (1) spermatozoa motility is one of key factors that influence on fertilizing ability of sperm, (2) a high fertilizing ability of sperm is obtained after dilution in saline solutions rather than in freshwater and (3) a maximum fertilization rate occurs in buffered saline solution containing 0.2 mM L?1 K+. There is also a good correlation between biochemical characteristics of seminal plasma and fertilizing ability of sperm. 相似文献
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Reannon L. Smith Tom W. May Jatinder Kaur Tim Sawbridge Ross Mann Jacky Edwards 《Plant pathology》2021,70(3):689-698
A strain of Podosphaera clandestina has been highlighted as a priority pest threat to the Australian cherry industry. Australia currently has no records of powdery mildew on cherry (Prunus avium). P. clandestina is reported to cause disease on a range of Rosaceae genera including Crataegus and Prunus; in Australia, P. clandestina has only been recorded on Crataegus. A recent species revision identified Podosphaera cerasi on P. avium as a separate species from P. clandestina. Therefore, a revision of which powdery mildew species is present in Australia on Crataegus is required to inform Australian plant biosecurity. Reference collection specimens from the Victorian Plant Pathology Herbarium (VPRI) recorded as Podosphaera spp. collected between 1889 to 2008 on cherry and three other host plant genera from Australia and overseas were sampled for DNA extraction and next-generation sequencing (NGS). Sequence data from preserved specimens were successfully mapped to internal transcribed spacer (ITS) sequences of P. clandestina in the strict sense, P. cerasi, and Podosphaera prunicola, and chloroplast matK sequences were used to identify plant hosts. Australian specimens on Crataegus hosts were P. clandestina in the strict sense and specimens on Prunus from the USA were identified as P. cerasi and P. prunicola. The outcome of this study confirmed the powdery mildew on Australian Crataegus specimens to be P. clandestina and none of the cherry powdery mildews (Podosphaera pruni-avium, P. cerasi, or P. prunicola) are present on Australian specimens in the VPRI collection, which suggests they are not present in Australia. 相似文献
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Mei M Ruan JQ Wu WJ Zhou RN Lei JP Zhao HY Yan R Wang YT 《Journal of agricultural and food chemistry》2012,60(9):2299-2308
Mulberroside A (MulA) is one of the main bioactive constituents in mulberry (Morus alba L.). This study examined the determining factors for previously reported oral pharmacokinetic profiles of MulA and its bacterial metabolite oxyresveratrol (OXY) on in vitro models. When incubated anaerobically with intestinal bacteria, MulA underwent rapid deglycosylation and generated two monoglucosides and its aglycone OXY sequentially. MulA exhibited a poor permeability and predominantly traversed Caco-2 cells via passive diffusion; yet, the permeation of OXY across Caco-2 cells was much more rapid and involved efflux (both p-glycoprotein and MRPs)-mediated mechanisms. Moreover, OXY underwent extensive hepatic glucuronidation; yet, the parent MulA was kept intact in liver subcellular preparations. There was insignificant species difference in intestinal bacterial conversion of MulA and the extent of OXY hepatic glucuronidation between humans and rats, while OXY exhibited a distinct positional preference of glucuronidation in the two species. Overall, these findings revealed a key role of intestinal bacterial conversion in absorption and systemic exposure of MulA and its resultant bacterial metabolite OXY in oral route in humans and rats and warranted further investigational emphasis on OXY and its hepatic metabolites for understanding the benefits of mulberry. 相似文献
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The role of Ca2+ and Na+ membrane transport in brook trout (Salvelinus fontinalis) spermatozoa motility 总被引：1，自引：0，他引：1
Olga Bondarenko Borys Dzyuba Jacky Cosson Marek Rodina Otomar Linhart 《Fish physiology and biochemistry》2014,40(5):1417-1421
The role of environmental ion composition and osmolality in Ca2+ signaled activation was assessed in spermatozoa of brook trout Salvelinus fontinalis. Milt from ten mature males was obtained by abdominal massage. Spermatozoa motility was evaluated in 0, 100, and 300 mOsm/kg NaCl or sucrose solutions, buffered by 10 mM Tris–HCl pH 8.5. For investigation of spermatozoa reaction to external Ca2+ concentration, 2 mM ethylene glycol tetraacetic acid (EGTA) was added to the activation media as a calcium ions chelator. For investigation of the effect of external Na+ concentration in conditions of low external Ca2+, 100 µM amiloride was added to the EGTA-containing solutions as a Na+ transport blocker. Low motility was observed in sucrose (Na+ free) solutions containing 2 mM EGTA but not in Na+ solutions containing 2 mM EGTA. Addition of amiloride led to significantly increased motility (P < 0.05) compared with sucrose (Na+ free) solutions containing 2 mM EGTA. We conclude that Na+ transport in Ca2+-free solutions plays a regulatory role in brook trout spermatozoa activation. The influence of competitive Na+ and Ca2+ transport on the control of spermatozoa activation requires further study with respect to its application for improvement of artificial activation and storage media. 相似文献
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Predictive erosion models are useful tools for evaluating the impact of land-use practices on soil and water properties, and as often used by environmental protection authorities, for setting guidelines and standards for regulation purposes. This study examines the application of three erosion models of varying complexity and design for predicting runoff and soil erosion from logged forest compartments in south eastern Australia. These are: the Universal Soil Loss Equation (USLE), the Water Erosion Prediction Project (WEPP), and TOPOG, a physically based hydrologic modelling package. Data on rates of soil loss and redistribution collected during a series of large-scale rainfall simulator experiments were used as model input parameters and validation. The models were evaluated in terms of general ease of use, input data requirements and accuracy of process understanding and prediction. Results suggest that in this application the USLE overestimated soil loss, and have the limitation that it does not predict sediment yield or sediment redistribution for specific storm events. When used at the hillslope scale, WEPP and TOPOG have predicted runoff and soil loss reasonably well, particularly on disturbed surfaces such as skid trails. On less disturbed surfaces such as the general harvesting area, both models performed less accurately, generally under-predicting soil loss and sediment yield, notably on sites with low observed values. The complexity and data requirements of WEPP and TOPOG limit their usability as a general-purpose, erosion hazard predicting tool. In terms of process understanding, none of the existing models accurately depict the nature and extent of sediment redistribution quantified in the rainfall simulator experiments. In order to advance the application and accuracy of modelling tools in forestry environments, this redistribution process should be considered integral to the refinement and redevelopment of future models. 相似文献