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61.
The literature remains unclear about the effects of prenatal cocaine exposure on child development. Meanwhile, the implications for public policy and treatment and for our scientific understanding of the toxicity of cocaine are substantial. In this article we describe; (1) our current understanding of the effects of prenatal cocaine use and child outcome, (2) the issues that need to be investigated, and (3) implications for treatment of cocaine exposed children. Findings from our database of the published literature shows that our knowledge is still limited, scattered, and compromised by methodological problems that mitigate any conclusions about whether or not or how prenatal cocaine exposure affects child outcome. The cocaine problem is more complicated than first envisioned--it is a multifactorial problem including the use of other drugs, parenting, and environmental lifestyle issues. However, we also show that, even though the effects may be more subtle than initially anticipated, prenatal cocaine exposure will substantially increase in the number of school age children who will need special education services. Clinicians working with these children and families need to be prepared to address psychosocial and environmental issues, as well as developmental performance, in order to optimize their assessment and intervention. 相似文献
62.
Martin A. Green Keith Emery Yoshihiro Hishikawa Wilhelm Warta Ewan D. Dunlop 《Progress in Photovoltaics: Research and Applications》2014,22(7):701-710
Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and new entries since January 2014 are reviewed. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
63.
Eduarda Cristovam Caroline Russell Alistair Paterson Ewan Reid 《Food quality and preference》2000,11(6):97-444
Espresso, cappuccino and latte are new coffee products entering the daily lives of many consumers. There is increasing consumption of such speciality coffees but no sensory basis for new product development. This study was designed to meet this need. Preference in 100 consumers was studied using six espresso blends of coffee beans. Blends were specifically developed to match key European and North American styles. Products prepared were both espresso and espresso-milk coffees. It was observed that females and males had different preferences for espresso coffee but that this effect was reduced on addition of milk. Gender of target consumer, and end use of espresso, should be thus considered in developing coffee blends. In this way acceptability in specific or target groups of consumers can be maximised. In addition individuals may experience a development of appreciation of coffee character reflected in a change in preference. 相似文献
64.
Ewan Galloway Marc Armbrüster Kirill Kovnir Mintcho S. Tikhov Richard M. Lambert 《Journal of Catalysis》2009,261(1):60-65
The phase pure, unsupported intermetallic compound PtZn is intrinsically active and selective for chemoselective hydrogenation of crotonaldehyde to crotyl alcohol in the absence of any support effects or auxiliary phases. During un-promoted reaction conditions, the PtZn surface becomes platinum enriched within the XPS sampling depth with respect to the 1:1 bulk stoichiometry. Catalyst modification by co-feeding ppm levels of bromoethane results in (i) surface enrichment by zinc, (ii) pronounced formation of a chemically distinct Znδ+ species and (iii) substantial improvements in selectivity toward crotyl alcohol (up to 88% at 10% reactant conversion). Bromoethane promotion acts both by suppressing formation of the undesired products and by enhancing crotyl alcohol formation, likely due to activation of the CO bond by coordination to the Znδ+ sites. Haloalkanes containing F, Cl or I do not induce any significant effects in either surface composition or electronic structure, serving only to poison the system. 相似文献
65.
Peter R. Foster Alan J. Dickson Alexander Stenhouse Ewan P. Walker 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1986,36(10):461-466
Precipitation is the principal technique used by the blood plasma fractionation industry for the separation and concentration of human proteins for clinical use. Although precipitation has many attractions it is particularly difficult to control and the resultant overshoot of key parameters is responsible for loss of product yield and sometimes quality. Much of this problem is due to the inefficiency of mixing and heat transfer in large bulk volumes of protein solution; hence control is limited by the process design. Therefore we have applied the concept of continuous-flow processing to scale-down process volumes, to improve the efficiency of mixing and heat transfer and to allow the opportunity for in-line monitoring and control of important parameters. Ten years experience with a routine manufacturing process of this type has illustrated the benefits of this approach and has led to the modernisation of the process with replacement of centralised computer control by a microprocessor-based system. 相似文献
66.
Effects of intramuscular injections of selenium and vitamin E on lesions in pigs with selenium-vitamin E deficiency syndrome were determined in 2 factorial experiments, using a total 69 pigs. The pigs were fed a selenium-vitamin E deficient, 22.3% protein ration, supplemented with methionine, minerals, and vitamins. Weekly intramuscular injections of isotonic saline solution, vitamin E, selenium, or vitamin E and selenium were given to the respective treatment groups. Selenium-vitamin E deficiency lesions occurred only in pigs that were given saline injections. Weekly intramuscular injections of either selenium (as selenous acid buffered to pH (7.3) at the rate of 0.05 mg/kg of body weight or vitamin E at the rate of 20 IU/kg of body weight or the combination of selenium and vitamin E prevented cardiac and skeletal myodegeneration, hepatic necrosis, and death. Significant increases of serum aspartate aminotransferase activity values were noted in pigs with liver, heart, or skeletal muscle lesions, but these increases were not correlated with the extent of the lesions. Vascular lesions, epicardial and endocardial hemorrhages, and yellow discoloration of body fat were not features of this experimentally induced disease. These lesions may be related to factors other than the deficiency of selenium, vitamin E, or selenium and vitamin E in rations previously used in reported studies. 相似文献
67.
Yang Z Xiang F Minter EJ Lü K Chen Y Montagnes DJ 《Journal of hazardous materials》2011,190(1-3):113-118
Elevated nitrite and microcystin concentrations co-occur during degradation of Microcystis blooms and are toxic to aquatic organisms. We studied the relative and combined effects of these on Daphnia obtusa life-history. Nitrite and microcystin-LR treatments were: 0, 1, 3 mg L(-1) and 0, 10, 100, 300 μg L(-1), respectively. Experiments were factorial with 12 treatment combinations. Incubations were 15 d and recorded: moult number; time to first batch of eggs; time to first clutch; size at first batch of eggs; size at first clutch; number of clutches per female; number of offspring per clutch; total offspring per female. Interactive effects of the toxins occurred for time to first batch of eggs and time to first clutch. The remaining traits were negatively affected by nitrite: a significant decrease occurred in number of offspring per clutch and total number of offspring per mother (both decreased by ~ 50%); total clutches per mother; number of moults; mother size at first clutch; and first appearance of eggs (primarily at the highest nitrite concentration). We support the literature, recognising nitrite is toxic, and although Microcystis is toxic to zooplankton, the main threat is not from dissolved microcystin but from degradative products such as nitrite. 相似文献
68.
A site investigation and sampling was carried out on a sulfate-attacked concrete structure in Bapanxia Hydraulic Power Plant in Western China. The concrete had been exposed to ground water containing substantial concentrations of salts (SO42−, CO32− and Cl−) for about 6 years and was analyzed with X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), laser-Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. It is shown that a white mushy mixture consisting of thaumasite, ettringite, gypsum and calcite is present in the residual concrete. This paper reports the first instance of the thaumasite form of sulfate attack of concrete in China. 相似文献
69.
Potential of solar electricity generation in the European Union member states and candidate countries 总被引:5,自引:0,他引:5
During the years 2001–2005, a European solar radiation database was developed using a solar radiation model and climatic data integrated within the Photovoltaic Geographic Information System (PVGIS). The database, with a resolution of 1 km × 1 km, consists of monthly and yearly averages of global irradiation and related climatic parameters, representing the period 1981–1990. The database has been used to analyse regional and national differences of solar energy resource and to assess the photovoltaic (PV) potential in the 25 European Union member states and 5 candidate countries. The calculation of electricity generation potential by contemporary PV technology is a basic step in analysing scenarios for the future energy supply and for a rational implementation of legal and financial frameworks to support the developing industrial production of PV. Three aspects are explored within this paper: (1) the expected average annual electricity generation of a ‘standard’ 1 kWp grid-connected PV system; (2) the theoretical potential of PV electricity generation; (3) determination of required installed capacity for each country to supply 1% of the national electricity consumption from PV. The analysis shows that PV can already provide a significant contribution to a mixed renewable energy portfolio in the present and future European Union. 相似文献
70.
Derek J. Gardiner Ewan M. Baird Carolyn Craggs Martin P. Dare-Edwards John C. Bell 《Lubrication Science》1989,1(4):301-313
The design and operation of two closely-related pieces of apparatus which allow the acquisition of Raman spectra from lubricant fluids ‘in lubro’ in an elastohydrodynamic contact are reported. Spectroscopic sensitivity was not sufficient to allow a detailed structural interpretation of the spectra under these extreme conditions. However, the systems have been used in a novel way to obtain profiles and maps of the pressure distribution, as experienced by the fluid in the working elastohydrodynamic contact. 相似文献