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排序方式: 共有1762条查询结果,搜索用时 15 毫秒
1.
J Byrne S Kienzle D Johnson G Duke V Gannon B Selinger J Thomas 《Water science and technology》2006,53(10):327-334
Long-term trends in alpine and prairie snow pack accumulation and melt are affecting streamflow within the Oldman River Basin in southern Alberta, Canada. Unchecked rural and urban development also has contributed to changes in water quality, including enhanced microbial populations and increased waterborne pathogen occurrence. In this study we look at changing environment within the Oldman River Basin and its impact on water quality and quantity. The cumulative effects include a decline in net water supplies, and declining quality resulting in increased risk of disease. Our data indicates that decreases in the rate of flow of water can result in sedimentation of bacterial contaminants within the water column. Water for ecosystems, urban consumption, recreation and distribution through irrigation is often drawn from waterholding facilities such as dams and weirs, and concern must be expressed over the potential for contaminate build-up and disproportionate potential of these structures to pose a risk to human and animal health. With disruption of natural flow rates for water resulting from environmental change such as global warming and/or human intervention, increased attention needs to be paid to use of best management practices to protect source water supplies. 相似文献
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R Byrne 《Canadian Metallurgical Quarterly》1998,69(7):24-6 contd; quiz 27
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Expanded polytetrafluoroethylene (ePTFE) membranes were modified by graft copolymerization with methacryloxyethyl phosphate (MOEP) in methanol and 2‐butanone (methyl ethyl ketone (MEK)) at ambient temperature using gamma irradiation. The effect of dose rate (0.46 and 4.6 kGy h?1), monomer concentration (1–40 %) and solvent were studied and the modified membranes were characterized by weight increase, X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). XPS was used to determine the % degree of surface coverage using the C? F (ePTFE membrane) and the C? C (MOEP graft copolymer) peaks. Grafting yield, as well as surface coverage, were found to increase with increasing monomer concentration and were significantly higher for samples grafted in MEK than in methanol solution. SEM images showed distinctly different surface morphologies for the membranes grafted in methanol (smooth) and MEK (globular), hence indicating phase separation of the homopolymer in MEK. We propose that in our system, the non‐solvent properties of MEK for the homopolymer play a more important role than solvent chain transfer reactions in determining grafting outcomes. Copyright © 2005 Society of Chemical Industry 相似文献
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D Brodaty G Dreyfus C Dubois P De Lentdecker C Barbagelatta PF Bouchet LJ Couderc O Bletry P Honderlick D Guilmet 《Canadian Metallurgical Quarterly》1998,91(12):1525-1529
The authors report a case of giant cell myocarditis leading to rapidly progressive cardiac failure despite immuno-suppressor treatment in a 20 year old woman. The cardiac failure was successfully managed by implantation of a left ventricular assist device and then cardiac transplantation. The problems encountered underline the importance of accurate diagnosis by endomyocardial biopsy before undertaking treatment and the difficulties in the choice of appropriate method of assistance in this indication. Giant cell myocarditis is a rare cause of cardiac failure and should be considered in the differential diagnosis in view of its clinical features and risk of progression. The literature and the therapeutic implications are discussed. 相似文献
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PF Beales 《Canadian Metallurgical Quarterly》1997,91(7):713-718
Mortality from malarial anaemia and malarial infection in those who are already anaemic yet have some degree of compensation is now beginning to receive the attention it deserves. It is of particular concern in Africa and especially in young children and pregnant women. The asymptomatic parasitaemia remaining after poor response to full antimalarial treatment may lead to life-threatening anaemia; as drug-resistant strains of the malarial parasite proliferate this is becoming increasingly important. It is now possible to estimate haemoglobin levels, simply, cheaply, easily and safely, using a haemoglobin colour scale which is being developed by the World Health Organization. The potential and practical value of this scale in malaria-control programmes was demonstrated in a small, preliminary trial in 1995. Estimation of anaemia should become an additional parameter in the traditional malariometric survey. Haemoglobin concentrations should also be taken into consideration in the management of malaria patients at the primary-care level, particularly in deciding whether a patient should be referred to an appropriate treatment centre. The accurate prediction of clinical outcome of malaria and anaemia, and indication of the appropriate action (determined by a case-based reasoning device) should be possible in the near future. 相似文献
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