17 resultados para Validation of test results

em Aston University Research Archive


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CONTEXT: The homeless are a significant group within society, which is increasing in size. They have demonstrably greater physical and mental health needs than the housed, and yet often have difficulty accessing primary health care. Medical 'reluctance' to look after homeless people is increasingly suggested as part of the problem. Medical education may have a role in ameliorating this. OBJECTIVES: This paper reports on the development and validation of a questionnaire specifically developed to measure medical students' attitudes towards the homeless. METHOD AND RESULTS: The Attitudes Towards the Homeless Questionnaire, developed using the views of over 370 medical students, was shown to have a Pearson test-retest reliability correlation coefficient of 0.8 and a Cronbach's alpha coefficient of 0.74. CONCLUSIONS: The Attitudes Towards the Homeless Questionnaire appears to be a valid and reliable instrument, which can measure students' attitudes towards the homeless. It could be a useful tool in assessing the effectiveness of educational interventions.

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OBJECTIVE: The authors developed and validated a clozapine-specific side-effects scale capable of eliciting the subjectively unpleasant side-effects of clozapine. METHODS: Questions from the original Glasgow Antipsychotic Side-effects Scale (GASS) were compared to a list of the most commonly reported clozapine side-effects and those with a significant subjective burden were included in the GASS for Clozapine (GASS-C). The original authors of the GASS and a group of mental health professionals from the UK and Ireland were enlisted to comment on the questions in the GASS-C based on their clinical experience. 110 clozapine outpatients from two sites completed the GASS-C, the original GASS and a repeat GASS-C. Statistical analyses were performed using SPSS for Windows version 19. RESULTS: The GASS-C was shown to have construct validity, in that Spearman's correlation coefficient was 0.816 (p<0.001) with the original GASS, whilst Cohen's kappa coefficient was >0.77 (p<0.001) for one question and >0.81 (p<0.001) for remaining relevant questions. GASS-C was also shown to have strong test-retest reliability, in that Cronbach's alpha coefficient was >0.907 (p<0.001), whilst Cohen's kappa coefficient was >0.81 (p<0.001) for 12 questions and >0.61 (p<0.001) for the remaining four questions. CONCLUSION: The GASS-C is a valid and reliable clinical tool to enable a systematic assessment of the subjectively unpleasant side-effects of clozapine. Future research should focus on how the scale can be utilised as a clinical tool to improve real-world outcomes such as adherence to clozapine therapy and quality of life.

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The involvement of oxidatively modified low density lipoprotein (LDL) in the development of CHD is widely described. We have produced two antibodies, recognizing the lipid oxidation product malondialdehyde (MDA) on whole LDL or ApoB-100. The antibodies were utilized in the development of an ELISA for quantitation of MDA-LDL in human plasma. Intra- and inter-assay coefficients of variation (% CV) were measured as 4.8 and 7.7%, respectively, and sensitivity of the assay as 0.04 μg/ml MDA-LDL. Recovery of standard MDA-LDL from native LDL was 102%, indicating the ELISA to be specific with no interference from other biomolecules. Further validation of the ELISA was carried out against two established methods for measurement of lipid peroxidation products, MDA by HPLC and F2-isoprostanes by GC-MS. Results indicated that MDA-LDL is formed at a later stage of oxidation than either MDA or F2- isoprostanes. In vivo analysis demonstrated that the ELISA was able to determine steady-state concentrations of plasma MDA-LDL (an end marker of lipid peroxidation). A reference range of 34.3 ± 8.8 μg/ml MDA-LDL was established for healthy individuals. Further, the ELISA was used to show significantly increased plasma MDA-LDL levels in subjects with confirmed ischemic heart disease, and could therefore possibly be of benefit as a diagnostic tool for assessing CHD risk. © 2003 Elsevier Inc.

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Innovation has long been an area of interest to social scientists, and particularly to psychologists working in organisational settings. The team climate inventory (TCI) is a facet-specific measure of team climate for innovation that provides a picture of the level and quality of teamwork in a unit using a series of Likert scales. This paper describes its Italian validation in 585 working group members employed in health-related and other contexts. The data were evaluated by means of factorial analysis (including an analysis of the internal consistency of the scales) and Pearson’s product moment correlations. The results show the internal consistency of the scales and the satisfactory factorial structure of the inventory, despite some variations in the factorial structure mainly due to cultural differences and the specific nature of Italian organisational systems.

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The object of this work was to further develop the idea introduced by Muaddi et al (1981) which enables some of the disadvantages of earlier destructive adhesion test methods to be overcome. The test is non-destructive in nature but it does need to be calibrated against a destructive method. Adhesion is determined by measuring the effect of plating on internal friction. This is achieved by determining the damping of vibrations of a resonating specimen before and after plating. The level of adhesion was considered by the above authors to influence the degree of damping. In the major portion of the research work the electrodeposited metal was Watt's nickel, which is ductile in nature and is therefore suitable for peel adhesion testing. The base metals chosen were aluminium alloys S1C and HE9 as it is relatively easy to produce varying levels of adhesion between the substrate and electrodeposited coating by choosing the appropriate process sequence. S1C alloy is the commercially pure aluminium and was used to produce good adhesion. HE9 aluminium alloy is a more difficult to plate alloy and was chosen to produce poorer adhesion. The "Modal Testing" method used for studying vibrations was investigated as a possible means of evaluating adhesion but was not successful and so research was concentrated on the "Q" meter. The method based on the use of a "Q" meter involves the principle of exciting vibrations in a sample, interrupting the driving signal and counting the number of oscillations of the freely decaying vibrations between two known preselected amplitudes of oscillations. It was not possible to reconstruct a working instrument using Muaddi's thesis (1982) as it had either a serious error or the information was incomplete. Hence a modified "Q" meter had to be designed and constructed but it was then difficult to resonate non-magnetic materials, such as aluminium, therefore, a comparison before and after plating could not be made. A new "Q" meter was then developed based on an Impulse Technique. A regulated miniature hammer was used to excite the test piece at the fundamental mode instead of an electronic hammer and test pieces were supported at the two predetermined nodal points using nylon threads. This instrument developed was not very successful at detecting changes due to good and poor pretreatments given before plating, however, it was more sensitive to changes at the surface such as room temperature oxidation. Statistical analysis of test results from untreated aluminium alloys show that the instrument is not always consistent, the variation was even bigger when readings were taken on different days. Although aluminium is said to form protective oxides at room temperature there was evidence that the aluminium surface changes continuously due to film formation, growth and breakdown. Nickel plated and zinc alloy immersion coated samples also showed variation in Q with time. In order to prove that the variations in Q were mainly due to surface oxidation, aluminium samples were lacquered and anodised Such treatments enveloped the active surfaces reacting with the environment and the Q variation with time was almost eliminated especially after hard anodising. This instrument detected major differences between different untreated aluminium substrates.Also Q values decreased progressively as coating thicknesses were increased. This instrument was also able to detect changes in Q due to heat-treatment of aluminium alloys.

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Lipid peroxidation products like malondialdehyde, 4-hydroxynonenal and F(2)-isoprostanes are widely used as markers of oxidative stress in vitro and in vivo. This study reports the results of a multi-laboratory validation study by COST Action B35 to assess inter-laboratory and intra-laboratory variation in the measurement of lipid peroxidation. Human plasma samples were exposed to UVA irradiation at different doses (0, 15 J, 20 J), encoded and shipped to 15 laboratories, where analyses of malondialdehyde, 4-hydroxynonenal and isoprostanes were conducted. The results demonstrate a low within-day-variation and a good correlation of results observed on two different days. However, high coefficients of variation were observed between the laboratories. Malondialdehyde determined by HPLC was found to be the most sensitive and reproducible lipid peroxidation product in plasma upon UVA treatment. It is concluded that measurement of malondialdehyde by HPLC has good analytical validity for inter-laboratory studies on lipid peroxidation in human EDTA-plasma samples, although it is acknowledged that this may not translate to biological validity.

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BACKGROUND: Gilles de la Tourette syndrome (GTS) is a chronic childhood-onset neuropsychiatric disorder with a significant impact on patients' health-related quality of life (HR-QOL). Cavanna et al. (Neurology 2008; 71: 1410-1416) developed and validated the first disease-specific HR-QOL assessment tool for adults with GTS (Gilles de la Tourette Syndrome-Quality of Life Scale, GTS-QOL). This paper presents the translation, adaptation and validation of the GTS-QOL for young Italian patients with GTS. METHODS: A three-stage process involving 75 patients with GTS recruited through three Departments of Child and Adolescent Neuropsychiatry in Italy led to the development of a 27-item instrument (Gilles de la Tourette Syndrome-Quality of Life Scale in children and adolescents, C&A-GTS-QOL) for the assessment of HR-QOL through a clinician-rated interview for 6-12 year-olds and a self-report questionnaire for 13-18 year-olds. RESULTS: The C&A-GTS-QOL demonstrated satisfactory scaling assumptions and acceptability. Internal consistency reliability was high (Cronbach's alpha > 0.7) and validity was supported by interscale correlations (range 0.4-0.7), principal-component factor analysis and correlations with other rating scales and clinical variables. CONCLUSIONS: The present version of the C&A-GTS-QOL is the first disease-specific HR-QOL tool for Italian young patients with GTS, satisfying criteria for acceptability, reliability and validity. © 2013 - IOS Press and the authors. All rights reserved.

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Objective - The aim of the current study was to validate child (PFA-QL) and parent–proxy (PFA-QL-PF) versions of the scale in a specialist allergy clinic and in parents of children with food allergy. Methods - For the clinic sample, a generic QoL scale (PedsQL) and the PFA-QL were completed by 103 children (age 6–16 yrs) with peanut or tree nut allergy; test–retest reliability of the PFA-QL was tested in 50 stable patients. For the non-clinical sample, 756 parents of food allergic children completed the PFA-QL-PF, the Child Health Questionnaire (CHQ-PF50), Food Allergy Quality of Life Parental Burden Scale (FAQL-PB) and a Food Allergy Impact Measure. Results - The PFA-QL and PFA-QL-PF had good internal consistency (a's of 0.77–0.82), and there was moderate-to-good agreement between the generic- and disease-specific questionnaires. The PFA-QL was stable over time in the clinic sample, and in both samples, girls were reported to have poorer QoL than boys. Conclusions - The PFA-QL and PFA-QL-PF are reliable and valid scales for use in both clinical and non-clinical populations. Unlike other available tools, they were developed and validated in the UK and thus provide a culture-specific choice for research, clinical trials and clinical practice in the UK. Validation in other countries is now needed.

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Purpose - Food allergy can have a profound effect on quality of life (QoL) of the family. The Food Allergy Quality of Life—Parental Burden Questionnaire (FAQL-PB) was developed on a US sample to assess the QoL of parents with food allergic children. The aim of this study was to examine the reliability and validity of the FAQL-PB in a UK sample and to assess the effect of asking about parental burden in the last week compared with parental burden in general, with no time limit for recall given. Methods - A total of 1,200 parents who had at least one child with food allergy were sent the FAQL-PB and the Child Health Questionnaire (CHQ-PF50); of whom only 63 % responded. Results - Factor analysis of the FAQL-PB revealed two factors: limitations on life and emotional distress. The total scale and the two sub-scales had high internal reliability (all a > 0.85). There were small to moderate but significant correlations between total FAQL-PB scores and health and parental impact measures on the CHQ-PF50 (p < 0.01). Significantly greater parental burden was reported for the no-time limited compared with the time-limited version (p < 0.01). Conclusions - The FAQL-PB is a reliable and valid measure for use in the UK. The scale could be used in clinic to assess the physical and emotional quality of life in addition to the impact on total quality of life.

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This thesis begins with a review of the literature on team-based working in organisations, highlighting the variations in research findings, and the need for greater precision in our measurement of teams. It continues with an illustration of the nature and prevalence of real and pseudo team-based working, by presenting results from a large sample of secondary data from the UK National Health Service. Results demonstrate that ‘real teams’ have an important and significant impact on the reduction of many work-related safety outcomes. Based on both theoretical and methodological limitations of existing approaches, the thesis moves on to provide a clarification and extension of the ‘real team’ construct, demarcating this from other (pseudo-like) team typologies on a sliding scale, rather than a simple dichotomy. A conceptual model for defining real teams is presented, providing a theoretical basis for the development of a scale on which teams can be measured for varying extents of ‘realness’. A new twelve-item scale is developed and tested with three samples of data comprising 53 undergraduate teams, 52 postgraduate teams, and 63 public sector teams from a large UK organisation. Evidence for the content, construct and criterion-related validity of the real team scale is examined over seven separate validation studies. Theoretical, methodological and practical implications of the real team scale are then discussed.

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Protein carbonyls are widely analysed as a measure of protein oxidation. Several different methods exist for their determination. A previous study had described orders of magnitude variance that existed when protein carbonyls were analysed in a single laboratory by ELISA using different commercial kits. We have further explored the potential causes of variance in carbonyl analysis in a ring study. A soluble protein fraction was prepared from rat liver and exposed to 0, 5 and 15 min of UV irradiation. Lyophilised preparations were distributed to six different laboratories that routinely undertook protein carbonyl analysis across Europe. ELISA and Western blotting techniques detected an increase in protein carbonyl formation between 0 and 5 min of UV irradiation irrespective of method used. After irradiation for 15 min, less oxidation was detected by half of the laboratories than after 5 min irradiation. Three of the four ELISA carbonyl results fell within 95% confidence intervals. Likely errors in calculating absolute carbonyl values may be attributed to differences in standardisation. Out of up to 88 proteins identified as containing carbonyl groups after tryptic cleavage of irradiated and control liver proteins, only seven were common in all three liver preparations. Lysine and arginine residues modified by carbonyls are likely to be resistant to tryptic proteolysis. Use of a cocktail of proteases may increase the recovery of oxidised peptides. In conclusion, standardisation is critical for carbonyl analysis and heavily oxidised proteins may not be effectively analysed by any existing technique.

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A new mesoscale simulation model for solids dissolution based on an computationally efficient and versatile digital modelling approach (DigiDiss) is considered and validated against analytical solutions and published experimental data for simple geometries. As the digital model is specifically designed to handle irregular shapes and complex multi-component structures, use of the model is explored for single crystals (sugars) and clusters. Single crystals and the cluster were first scanned using X-ray microtomography to obtain a digital version of their structures. The digitised particles and clusters were used as a structural input to digital simulation. The same particles were then dissolved in water and the dissolution process was recorded by a video camera and analysed yielding: the overall dissolution times and images of particle size and shape during the dissolution. The results demonstrate the coherence of simulation method to reproduce experimental behaviour, based on known chemical and diffusion properties of constituent phase. The paper discusses how further sophistications to the modelling approach will need to include other important effects such as complex disintegration effects (particle ejection, uncertainties in chemical properties). The nature of the digital modelling approach is well suited to for future implementation with high speed computation using hybrid conventional (CPU) and graphical processor (GPU) systems.

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PurposeTo develop and validate a classification system for focal vitreomacular traction (VMT) with and without macular hole based on spectral domain optical coherence tomography (SD-OCT), intended to aid in decision-making and prognostication.MethodsA panel of retinal specialists convened to develop this system. A literature review followed by discussion on a wide range of cases formed the basis for the proposed classification. Key features on OCT were identified and analysed for their utility in clinical practice. A final classification was devised based on two sequential, independent validation exercises to improve interobserver variability.ResultsThis classification tool pertains to idiopathic focal VMT assessed by a horizontal line scan using SD-OCT. The system uses width (W), interface features (I), foveal shape (S), retinal pigment epithelial changes (P), elevation of vitreous attachment (E), and inner and outer retinal changes (R) to give the acronym WISPERR. Each category is scored hierarchically. Results from the second independent validation exercise indicated a high level of agreement between graders: intraclass correlation ranged from 0.84 to 0.99 for continuous variables and Fleiss' kappa values ranged from 0.76 to 0.95 for categorical variables.ConclusionsWe present an OCT-based classification system for focal VMT that allows anatomical detail to be scrutinised and scored qualitatively and quantitatively using a simple, pragmatic algorithm, which may be of value in clinical practice as well as in future research studies.

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A novel simulation model for pyrolysis processes oflignocellulosicbiomassin AspenPlus (R) was presented at the BC&E 2013. Based on kinetic reaction mechanisms, the simulation calculates product compositions and yields depending on reactor conditions (temperature, residence time, flue gas flow rate) and feedstock composition (biochemical composition, atomic composition, ash and alkali metal content). The simulation model was found to show good correlation with existing publications. In order to further verify the model, own pyrolysis experiments in a 1 kg/h continuously fed fluidized bed fast pyrolysis reactor are performed. Two types of biomass with different characteristics are processed in order to evaluate the influence of the feedstock composition on the yields of the pyrolysis products and their composition. One wood and one straw-like feedstock are used due to their different characteristics. Furthermore, the temperature response of yields and product compositions is evaluated by varying the reactor temperature between 450 and 550 degrees C for one of the feedstocks. The yields of the pyrolysis products (gas, oil, char) are determined and their detailed composition is analysed. The experimental runs are reproduced with the corresponding reactor conditions in the AspenPlus model and the results compared with the experimental findings.

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Highlights •This paper assesses the validity of the DMQ-R (Cooper, 1994) among university students in six different European countries. •Results provide support for similar DMQ-R factor structures across countries. •Drinking motives have similar meanings among European university students.