522 resultados para Microwavehydrothermal method
Resumo:
Samples of Forsythia suspensa from raw (Laoqiao) and ripe (Qingqiao) fruit were analyzed with the use of HPLC-DAD and the EIS-MS techniques. Seventeen peaks were detected, and of these, twelve were identified. Most were related to the glucopyranoside molecular fragment. Samples collected from three geographical areas (Shanxi, Henan and Shandong Provinces), were discriminated with the use of hierarchical clustering analysis (HCA), discriminant analysis (DA), and principal component analysis (PCA) models, but only PCA was able to provide further information about the relationships between objects and loadings; eight peaks were related to the provinces of sample origin. The supervised classification models-K-nearest neighbor (KNN), least squares support vector machines (LS-SVM), and counter propagation artificial neural network (CP-ANN) methods, indicated successful classification but KNN produced 100% classification rate. Thus, the fruit were discriminated on the basis of their places of origin.
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Reported homocysteine (HCY) concentrations in human serum show poor concordance amongst laboratories due to endogenous HCY in the matrices used for assay calibrators and QCs. Hence, we have developed a fully validated LC–MS/MS method for measurement of HCY concentrations in human serum samples that addresses this issue by minimising matrix effects. We used small volumes (20 μL) of 2% Bovine Serum Albumin (BSA) as surrogate matrix for making calibrators and QCs with concentrations adjusted for the endogenous HCY concentration in the surrogate matrix using the method of standard additions. To aliquots (20 μL) of human serum samples, calibrators or QCs, were added HCY-d4 (internal standard) and tris-(2-carboxyethyl) phosphine hydrochloride (TCEP) as reducing agent. After protein precipitation, diluted supernatants were injected into the LC–MS/MS. Calibration curves were linear; QCs were accurate (5.6% deviation from nominal), precise (CV% ≤ 9.6%), stable for four freeze–thaw cycles, and when stored at room temperature for 5 h or at −80 °C (27 days). Recoveries from QCs in surrogate matrix or pooled human serum were 91.9 and 95.9%, respectively. There was no matrix effect using 6 different individual serum samples including one that was haemolysed. Our LC–MS/MS method has satisfied all of the validation criteria of the 2012 EMA guideline.
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The need to attract and retain a high calibre cadre of public servants today has resulted in a renaissance of interest in public service motivation (PSM) within public management literature. This article outlines a study of PSM with graduate employees within an Australian public sector. The study extends our understanding of PSM by adopting a longitudinal, mixed method design, including surveys and individual interviews, to consider the effects of socialisation on levels of PSM. Results show an organisation's mission and values do not affect individual PSM while work type and communication style is vital and organisational socialisation can provide a negative influence.
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There is much for non-Indigenous researchers to consider when researching in Indigenous contexts. This paper is a story of discovery for two researchers working on a project with the Indigenous Sports Program section of the Australian Sports Commission. It documents the slow, meticulous and sometimes clumsy steps taken to gain access to communities and conduct research guided by a social justice ethic. The research was successful in that eventually it was possible to develop the trust of individuals and some of the Indigenous communities more broadly, so that information could be gathered and given within the context of shared understandings and mutual interest. However, it is the turbulent journey, filled as it is, with latent tendencies, privileged assumptions and eventually reflexive readings of the data, which remains the focus of this paper. Tentative recommendations are offered to those wishing to advance this politically and epistemologically challenging approach to culturally based research
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In this chapter, I consider the efficacy of creative practice as a research method, concentrating specifically on its applications in the performing arts, using one of my own recent projects, The Ex/centric Fixations Project (2009), as an example.
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This invention concerns the control of rotating excavation machinery, for instance to avoid collisions with obstacles. In a first aspect the invention is a control system for autonomous path planning in excavation machinery, comprising: A map generation subsystem to receive data from an array of disparate and complementary sensors to generate a 3-Dimensional digital terrain and obstacle map referenced to a coordinate frame related to the machine's geometry, during normal operation of the machine. An obstacle detection subsystem to find and identify obstacles in the digital terrain and obstacle map, and then to refine the map by identifying exclusion zones that are within reach of the machine during operation. A collision detection subsystem that uses knowledge of the machine's position and movements, as well as the digital terrain and obstacle map, to identify and predict possible collisions with itself or other obstacles, and then uses a forward motion planner to predict collisions in a planned path. And, a path planning subsystem that uses information from the other subsystems to vary planned paths to avoid obstacles and collisions. In other aspects the invention is excavation machinery including the control system; a method for control of excavation machinery; and firmware and software versions of the control system.
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Porosity is one of the key parameters of the macroscopic structure of porous media, generally defined as the ratio of the free spaces occupied (by the volume of air) within the material to the total volume of the material. Porosity is determined by measuring skeletal volume and the envelope volume. Solid displacement method is one of the inexpensive and easy methods to determine the envelope volume of a sample with an irregular shape. In this method, generally glass beads are used as a solid due to their uniform size, compactness and fluidity properties. The smaller size of the glass beads means that they enter into the open pores which have a larger diameter than the glass beads. Although extensive research has been carried out on porosity determination using displacement method, no study exists which adequately reports micro-level observation of the sample during measurement. This study set out with the aim of assessing the accuracy of solid displacement method of bulk density measurement of dried foods by micro-level observation. Solid displacement method of porosity determination was conducted using a cylindrical vial (cylindrical plastic container) and 57 µm glass beads in order to measure the bulk density of apple slices at different moisture contents. A scanning electron microscope (SEM), a profilometer and ImageJ software were used to investigate the penetration of glass beads into the surface pores during the determination of the porosity of dried food. A helium pycnometer was used to measure the particle density of the sample. Results show that a significant number of pores were large enough to allow the glass beads to enter into the pores, thereby causing some erroneous results. It was also found that coating the dried sample with appropriate coating material prior to measurement can resolve this problem.
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In the health care industry, Job Satisfaction (JS) is linked with work performance, psychological well-being and employee turnover. Although research into JS among health professionals has a long history worldwide, there has been very little analysis in Vietnam. No study has addressed JS of preventive medicine workers in Vietnam, and there is no reliable and valid instrument in Vietnamese language and context for evaluation of JS in this group. This project was conducted to fill these gaps. The findings contribute evidence regarding factors that influence JS in this sector of the health industry that should be applied to personnel management policies and practices in Vietnam.
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This paper relates to the importance of impact of the chosen bottle-point method when conducting ion exchange equilibria experiments. As an illustration, potassium ion exchange with strong acid cation resin was investigated due to its relevance to the treatment of various industrial effluents and groundwater. The “constant mass” bottle-point method was shown to be problematic in that depending upon the resin mass used the equilibrium isotherm profiles were different. Indeed, application of common equilibrium isotherm models revealed that the optimal fit could be with either the Freundlich or Temkin equations, depending upon the conditions employed. It could be inferred that the resin surface was heterogeneous in character, but precise conclusions regarding the variation in the heat of sorption were not possible. Estimation of the maximum potassium loading was also inconsistent when employing the “constant mass” method. The “constant concentration” bottle-point method illustrated that the Freundlich model was a good representation of the exchange process. The isotherms recorded were relatively consistent when compared to the “constant mass” approach. Unification of all the equilibrium isotherm data acquired was achieved by use of the Langmuir Vageler expression. The maximum loading of potassium ions was predicted to be at least 116.5 g/kg resin.
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Any government deciding to invoke widespread change in its higher education sector through implementation of new policies impacts on every institution and all staff and students, often in both the time taken up and the heightened emotions caused. The central phenomenon that this study addresses is the process and consequences of policy changes in higher education in Australia. The aim of this article is to record the research design through the perspective (evaluation research), theoretical framework (program evaluation) and methods (content analysis, descriptive statistical analysis and bibliometric analysis) applied to the investigation of the 2003 federal government higher education reform package. This approach allows both the intended and unintended consequences arising from the policy implementation of three national initiatives focused on learning and teaching in higher education in Australia to surface. As a result, this program evaluation, also known in some disciplines as policy implementation analysis, will demonstrate the applicability of illuminative evaluation as a methodology and reinforce how program evaluation will assist and advise future government reform and policy implementation, and will serve as a legacy for future evaluative research.Any government deciding to invoke widespread change in its higher education sector through implementation of new policies impacts on every institution and all staff and students, often in both the time taken up and the heightened emotions caused. The central phenomenon that this study addresses is the process and consequences of policy changes in higher education in Australia. The aim of this article is to record the research design through the perspective (evaluation research), theoretical framework (program evaluation) and methods (content analysis, descriptive statistical analysis and bibliometric analysis) applied to the investigation of the 2003 federal government higher education reform package. This approach allows both the intended and unintended consequences arising from the policy implementation of three national initiatives focused on learning and teaching in higher education in Australia to surface. As a result, this program evaluation, also known in some disciplines as policy implementation analysis, will demonstrate the applicability of illuminative evaluation as a methodology and reinforce how program evaluation will assist and advise future government reform and policy implementation, and will serve as a legacy for future evaluative research.
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This paper presents a new metric, which we call the lighting variance ratio, for quantifying descriptors in terms of their variance to illumination changes. In many applications it is desirable to have descriptors that are robust to changes in illumination, especially in outdoor environments. The lighting variance ratio is useful for comparing descriptors and determining if a descriptor is lighting invariant enough for a given environment. The metric is analysed across a number of datasets, cameras and descriptors. The results show that the upright SIFT descriptor is typically the most lighting invariant descriptor.
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Exogenous adenosine causes a monophasic dilation of the coronary vessels in paced, perfused rat heart preparations. Because levels of endogenous adenosine in paced hearts may mask the presence of high potency adenosine receptors, we have developed a method to measure coronary vascular responses in a potassium-arrested heart. Hearts from adult male, Wistar rats were perfused at a constant flow rate of 10 mL/min in the nonrecirculating, Langendorff mode, using Krebs-Henseleit buffer. After 30 min, coronary perfusion pressure was 44 +/- 1 mmHg (mean +/- SEM). Hearts were then perfused with a modified Krebs-Henseleit buffer containing 35 mM potassium. Coronary perfusion pressure increased by 84 +/- 3 mmHg. Adenosine-induced reductions in coronary perfusion pressure were expressed as a percentage of the maximal increase in pressure produced by modified Krebs-Henseleit buffer from the equilibration level. A concentration-response curve for adenosine (n = 6) was biphasic and best described by the presence of two adenosine receptors, with negative log EC50 values of 8.8 +/- 0.3 and 4.3 +/- 0.1, representing 29 +/- 3 and 71 +/- 3%, respectively, of the observed response. Interstitial adenosine sampled by microdialysis during potassium arrest was 25% of the concentration found in paced hearts. Endogenous adenosine in nonarrested hearts may obscure the biphasic response of the coronary vessels to adenosine.
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This paper aims to develop a meshless approach based on the Point Interpolation Method (PIM) for numerical simulation of a space fractional diffusion equation. Two fully-discrete schemes for the one-dimensional space fractional diffusion equation are obtained by using the PIM and the strong-forms of the space diffusion equation. Numerical examples with different nodal distributions are studied to validate and investigate the accuracy and efficiency of the newly developed meshless approach.