914 resultados para Capillary Rise
Resumo:
A rapid, selective and specific capillary zone electrophoresis method to determine polyamines in organic extracts from roots of Canavalia ensiformis (Jack Beans) was developed using ultra violet (UV) detection. Canavalia ensiformis is relatively free from diseases and it is used as reference in allelopathy studies. Polyamines are widely distributed in plant and it could be involved in plant pathogen interactions. Optimal separation was achieved using 15 mmol.L-1formic acid (pH 3.0) + 4 mmol.L-1 imidazole as a background electrolyte. It was possible to identify and quantify the polyamines on herbal samples in the presence of other phytochemical substances and analyze them quickly (up to 6 min). The applicability of this method was evaluated in crude organic extracts from roots of Canavalia ensiformis.
Resumo:
A simple, fast, and sensitive liquid-liquid extraction method followed by nonaqueous capillary electrophoresis (LLE/NACE) was developed and validated for Simultaneous determination of four antidepressants (fluoxetine, sertraline, citalopram and paroxetine) in human plasma. Several experimental separation conditions using aqueous and nonaqueous media separation were tested by varying the electrolyte pH value (for aqueous medium) and the ionic strength concentration considering the similar mobility of the compounds. High-resolution separation was achieved with a mixture of 1.25 mol L(-1) of phosphoric acid in acetonitrile. The quantification limits of the LLE/CE method varied between 15 and 30 ng mL(-1), with a relative standard deviation (RSD) lower than 10.3%. The method was successfully applied in therapeutic drug monitoring and should be employed in the evaluation of plasma levels in urgent toxicological analysis. (C) 2009 Elsevier B.V. All rights reserved.
Resumo:
The performance of modular home made capillary electrophoresis equipment with spectrophotometric detection, at a visible region by means of a miniaturized linear charge coupled device, was evaluated for the determination of four food dyes. This system presents a simple but efficient home made cell detection scheme. A computer program that converts the spectral data after each run into the electropherograms was developed to evaluate the analytical parameters. The dyes selected for analytical evaluation of the system were Brilliant Blue FCF, Fast Green FCF, Sunset Yellow FCF, and Amaranth. Separation was carried out in a 29cm length and 75 mu m I.D fused silica capillary, using 10mmolL-1 borate buffer at pH 9, with separation voltage of 7.5kV. The detection limits for the dyes were between 0.3 and 1.5mgL-1 and the method presented adequate linearity over the ranges studied, with correlation coefficients greater than 0.99. The method was applied for determination and quantification of these dyes in fruit juices and candies.
Resumo:
Background: Newly graduated nurses are faced with a challenging work environment that may impede theirability to provide evidence-based practice. However, little is known about the trajectory of registered nurses’ use ofresearch during the first years of professional life. Thus, the aim of the current study was to prospectively examinethe extent of nurses’ use of research during the first five years after undergraduate education and specifically assesschanges over time.Method: Survey data from a prospective cohort of 1,501 Swedish newly graduated nurses within the nationalLANE study (Longitudinal Analyses of Nursing Education and Entry in Worklife) were used to investigate perceiveduse of research over the first five years as a nurse. The dependent variables consisted of three single itemsassessing instrumental, conceptual, and persuasive research use, where the nurses rated their use on a five-pointscale, from ‘never’ (1) to ‘on almost every shift’ (5). These data were collected annually and analyzed bothdescriptively and by longitudinal growth curve analysis.Results: Instrumental use of research was most frequently reported, closely followed by conceptual use, withpersuasive use occurring to a considerably lower extent. The development over time showed a substantial generalupward trend, which was most apparent for conceptual use, increasing from a mean of 2.6 at year one to 3.6 atyear five (unstandardized slope +0.25). However, the descriptive findings indicated that the increase started onlyafter the second year. Instrumental use had a year one mean of 2.8 and a year five mean of 3.5 (unstandardizedslope +0.19), and persuasive use showed a year one mean of 1.7 and a year five mean of 2.0 (unstandardized slope+0.09).Conclusion: There was a clear trend of increasing research use by nurses during their first five years of practice.The level of the initial ratings also indicated the level of research use in subsequent years. However, it took morethan two years of professional development before this increase ‘kicked in.’ These findings support previousresearch claiming that newly graduated nurses go through a ‘transition shock,’ reducing their ability to useresearch findings in clinical work.
Resumo:
Public and private actors increasingly cooperate in global governance, a realm previously reserved for states and intergovernmental organizations (IOs). This trend raises fascinating theoretical questions. What explains the rise in public-private institutions and their role in international politics? Who leads such institutional innovation and why? To address the questions, this paper develops a theory of the political demand and supply of public-private institutions and specifies the conditions under which IOs and non-state actors would cooperate, and states would support this public-private cooperation. The observable implications of the theoretical argument are evaluated against the broad trends in public-private cooperation and in a statistical analysis of the significance of demand and supply-side incentives in public-private cooperation for sustainable development. The study shows that public-private institutions do not simply fill governance gaps opened by globalization, but cluster in narrower areas of cooperation, where the strategic interests of IOs, states, and transnational actors intersect.
Resumo:
http://digitalcommons.colby.edu/atlasofmaine2006/1016/thumbnail.jpg
Resumo:
Maine's 3,500 miles of coastline is the longest coastline in the continental US. The goal of our study was to use GIS to estimate the impact future global sea level rise could potentially have on our state. We show the area of coastline and some of the economic and social impacts that would result from a rise of one meter and six meters. We used roads to estimate the impact on infrastructure and public building, including schools, libraries, hospitals, police and fire stations, as a measure of social impact. A sea level rise of six meters would result in a loss of over 650 km¬2 from coastal communities and cost the state of Maine over 3 million in repaving costs. Through our study, we hope coastal communities will be able to prepare for and react to the predicted changes in global sea level.
Resumo:
Absorbance detection in capillary electrophoresis (CE), offers an excellent mass sensitivity, but poor concentration detection limits owing to very small injection volumes (normally I to 10 nL). This aspect can be a limiting factor in the applicability of CE/UV to detect species at trace levels, particularly pesticide residues. In the present work, the optical path length of an on-column detection cell was increased through a proper connection of the column (75 mu m i.d.) to a capillary detection cell of 180 mu m optical path length in order to improve detectability. It is shown that the cell with an extended optical path length results in a significant gain in terms of signal to noise ratio. The effect of the increase in the optical path length has been evaluated for six pesticides, namely, carbendazim, thiabendazole, imazalil, procymidone triadimefon, and prochloraz. The resulting optical enhancement of the detection cell provided detection limits of ca. 0.3 mu g/mL for the studied compounds, thus enabling the residue analysis by CE/UV.
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)