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Measurement Techniques (measurement + techniques)
Selected AbstractsComparative Overview of Cardiac Output Measurement Methods: Has Impedance Cardiography Come of Age?CONGESTIVE HEART FAILURE, Issue 2 2000Anthony N. De Maria MD Cardiac output, usually expressed as liters of blood ejected by the left ventricle per minute, is a fundamental measure of the adequacy of myocardial function to meet the perfusion needs of tissue at any time. Decreases in cardiac output over time (when cardiac output is measured under similar conditions) may signal myocardial functional deterioration and the onset or progression of heart failure. Conversely, improvements in cardiac output may indicate a positive response to medical therapy. However, most methods for evaluating cardiac output are technically demanding, require specialized training and specialized environments for measurement, and are costly. Therefore, most measurement techniques are impractical for routine evaluation of disease progression and/or response to treatment in the prevention and/or management of heart failure. This paper provides a comparative overview of commonly employed cardiac output measurement strategies with emphasis on developments in impedance cardiography which suggest that impedance cardiography has the potential to make routine assessment and trending of cardiac output a viable alternative to assist in the management of both chronically and acutely ill patients, including those with heart failure. [source] Implementing life cycle assessment in product developmentENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 4 2003Gurbakhash Singh Bhander The overall aim of this paper is to provide an understanding of the environmental issues involved in the early stages of product development, and the capacity of Life Cycle Assessment (LCA) techniques to address these issues. The paper aims to outline the problems for the designer in evaluating the environmental benignity of a product from the outset, and to provide a framework for decision support based on the performance evaluation at different stages of the design process. The barriers that prevent product developers from using LCA are presented, as well as opportunities for introducing environmental criteria in the design process by meeting the designer's information requirements at the different life cycle stages. This can lead to an in-depth understanding of the attitudes of product developers towards the subject area, and an understanding of possible future directions for product development. This paper introduces an Environmentally Conscious Design method, and presents trade-offs between design degrees of freedom and environmental solutions. Life cycle design frameworks and strategies are also addressed. The paper collects experiences and ideas around the state-of-the-art in eco-design, from literature and personal experience, and provides eco-design life cycle assessment strategies. The end result of this presentation is to define the requirements for performance measurement techniques, and the environment needed to support life cycle evaluation throughout the evaluation of early stages of a product system. [source] Cerebral Damage in Epilepsy: A Population-based Longitudinal Quantitative MRI StudyEPILEPSIA, Issue 9 2005Rebecca S. N. Liu Summary:,Purpose: Whether cerebral damage results from epileptic seizures remains a contentious issue. We report on the first longitudinal community-based quantitative magnetic resonance imaging (MRI) study to investigate the effect of seizures on the hippocampus, cerebellum, and neocortex. Methods: One hundred seventy-nine patients with epilepsy (66 temporal lobe epilepsy, 51 extratemporal partial epilepsy, and 62 generalized epilepsy) and 90 control subjects underwent two MRI brain scans 3.5 years apart. Automated and manual measurement techniques identified changes in global and regional brain volumes and hippocampal T2 relaxation times. Results: Baseline hippocampal volumes were significantly reduced in patients with temporal lobe epilepsy and could be attributed to an antecedent neurologic insult. Rates of hippocampal, cerebral, and cerebellar atrophy were not syndrome specific and were similar in control and patient groups. Global and regional brain atrophy was determined primarily by age. A prior neurologic insult was associated with reduced hippocampal and cerebellar volumes and an increased rate of cerebellar atrophy. Significant atrophy of the hippocampus, neocortex, or cerebellum occurred in 17% of patients compared with 6.7% of control subjects. Patients with and without significant volume reduction were comparable in terms of seizure frequency, antiepileptic drug (AED) use, and epilepsy duration, with no identifiable risk factors for the development of atrophy. Conclusions: Overt structural cerebral damage is not an inevitable consequence of epileptic seizures. In general, brain volume reduction in epilepsy is the cumulative effect of an initial precipitating injury and age-related cerebral atrophy. Significant atrophy developed in individual patients, particularly those with temporal lobe and generalized epilepsy. Longer periods of observation may detect more subtle effects of seizures. [source] The neuroanatomy of grapheme,color synesthesiaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2009Lutz Jäncke Abstract Grapheme,color synesthetes perceive particular colors when seeing a letter, word or number (grapheme). Functional neuroimaging studies have provided some evidence in favor of a neural basis for this type of synesthesia. Most of these studies have reported extra activations in the fusiform gyrus, which is known to be involved in color, letter and word processing. The present study examined different neuroanatomical features (i.e. cortical thickness, cortical volume and cortical surface area) in a sample of 48 subjects (24 grapheme,color synesthetes and 24 control subjects), and revealed increased cortical thickness, volume and surface area in the right and left fusiform gyrus and in adjacent regions, such as the lingual gyrus and the calcarine cortex, in grapheme,color synesthetes. In addition, we set out to analyze structural connectivity based on fractional anisotropy (FA) measurements in a subsample of 28 subjects (14 synesthetes and 14 control subjects). In contrast to the findings of a recent neuroanatomical study using modern diffusion tensor imaging measurement techniques, we did not detect any statistically significant difference in FA between synesthetes and non-synesthetes in the fusiform gyri. Our study thus supports the hypothesis of local anatomical differences in cortical characteristics in the vicinity of the V4 complex. The observed altered brain anatomy in grapheme,color synesthetes might be the anatomical basis for this particular form of synesthesia but it is also possible that the detected effects are a consequence (rather than the primary cause) of the life-long experience of grapheme,color synesthesia. [source] Blood Pressure and Daily LifeGERMAN RESEARCH, Issue 1 2006Stefan Duschek Dr. Does chronically low blood pressure impair the brain's performance? Psychological performance tests and modern measurement techniques provide a novel answer [source] Canopy structure in savannas along a moisture gradient on Kalahari sandsGLOBAL CHANGE BIOLOGY, Issue 3 2004Robert J. Scholes Abstract Measurements of tree canopy architecture were made at six savanna sites on deep, sandy soils, along a gradient of increasing aridity. There was substantial variation in the leaf area estimated within each site, using the same sample frame, but different measurement techniques. The trends in canopy properties in relation to the aridity gradient were consistent, regardless of the technique used for estimating the properties. The effective plant area index for the tree canopy (the sum of the stem area index and the leaf area index (LAI)) declined from around 2 to around 0.8 m2 m,2 over a gradient of mean annual rainfall from 1000 to 350 mm. Stems contributed 2,5% of the tree canopy plant area index. Since the tree canopy cover decreased from 50% to 20% over this aridity range, the leaf area index within the area covered by tree canopies remained fairly constant at 3,4 m2 m,2. Tree leaves tended from a horizontal orientation to a more random orientation as the aridity increased. On the same gradient, the leaf minor axis dimension decreased from around 30 mm to around 3 mm, and the mean specific leaf area decreased from 14 to 5 m2 kgha,1. There was good agreement between LAI observed in the field using a line ceptometer and the LAI inferred by the MODIS sensor on the Terra satellite platform, 2 months later in the same season. [source] Using DCE and ranking data to estimate cardinal values for health states for deriving a preference-based single index from the sexual quality of life questionnaireHEALTH ECONOMICS, Issue 11 2009Julie Ratcliffe Abstract There is an increasing interest in using data derived from ordinal methods, particularly data derived from discrete choice experiments (DCEs), to estimate the cardinal values for health states to calculate quality adjusted life years (QALYs). Ordinal measurement strategies such as DCE may have considerable practical advantages over more conventional cardinal measurement techniques, e.g. time trade-off (TTO), because they may not require such a high degree of abstract reasoning. However, there are a number of challenges to deriving the cardinal values for health states using ordinal data, including anchoring the values on the full health,dead scale used to calculate QALYs. This paper reports on a study that deals with these problems in the context of using two ordinal techniques, DCE and ranking, to derive the cardinal values for health states derived from a condition-specific sexual health measure. The results were compared with values generated using a commonly used cardinal valuation technique, the TTO. This study raises some important issues about the use of ordinal data to produce cardinal health state valuations. Copyright © 2009 John Wiley & Sons, Ltd. [source] Towards a multidisciplinary approach to structuring in reduced saturated fat-based systems , a reviewINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 4 2010Paul Wassell Summary Although many food products are essentially emulsions, interest in the structuring of oil-continuous emulsions (and in specific cases water-continuous emulsions) is intense, particularly to meet the continuing challenge of reducing the degree of saturates in food systems. Consequently, it is necessary to observe the effects of structurants and to examine their impacts on current food systems. This is especially the case where novel structuring materials are used to wholly or partially replace traditional structurants. A multidisciplinary approach is discussed encompassing traditional and novel mechanisms considered able to structure within low saturated fat-based systems and which in themselves could also have emulsification properties. The presence of interfacial compositions as in emulsions requires a crucial understanding of the interactions within these compositions for the creation of building blocks in oil or fat structuring. Where a co-surfactant structure may be used, together with novel structurants, for example, wax esters, phytosterols, it is necessary to understand how these may influence interfacial film thickness, strength and flexibility. Understanding how to measure mechanical visco-elastic properties of structurant interactions both in model and real time dynamic measurements will be necessary to account for diffusion, orientation and self-assembly mechanisms. This review discusses combining traditional techniques with novel structurant technology; developing and validating dynamic measurement techniques; and investigation of real systems as opposed to purely model systems. [source] Radiographic clues to fractures of distal humerus in archaeological remainsINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 4 2001B Glencross Abstract Today, distal humeral fractures occur most frequently in children and adolescents, and are usually the result of a fall onto extended arms, or less often on flexed elbows. Trauma to the distal humerus at the physis and epiphyses often produces non-displaced or mildly displaced fractures that are difficult to recognize radiographically. To help identify these types of injuries, clinicians have developed two measurement techniques that are applied to the X-rays of the injured bones. In a preliminary attempt to assess the usefulness of these measurement techniques for recognizing trauma in archaeological skeletal remains, 25 humeri from two Ontario ossuary samples were submitted to radiography. Clinical data on distal humeral fractures, their incidence, and mechanisms of injury were also used to interpret the lifestyles and cultural activities of the aboriginal individuals under study. While only one healed fracture was suspected after gross observation, a total of four fractures were ultimately identified using the two measurements, the humerotangential-angle (HTA) and the anterior hunieral line (AHL). Our results provide indirect, but telling, evidence of accidental childhood injuries to distal humerus in an archaeological population. Copyright © 2001 John Wiley & Sons, Ltd. [source] Downturn Credit Portfolio Risk, Regulatory Capital and Prudential Incentives,INTERNATIONAL REVIEW OF FINANCE, Issue 2 2010DANIEL RÖSCH ABSTRACT This paper analyzes the level and cyclicality of bank capital requirement in relation to (i) the model methodologies through-the-cycle and point-in-time, (ii) four distinct downturn loss rate given default concepts, and (iii) US corporate and mortgage loans. The major finding is that less accurate models may lead to a lower bank capital requirement for real estate loans. In other words, the current capital regulations may not support the development of credit portfolio risk measurement models as these would lead to higher capital requirements and hence lower lending volumes. The finding explains why risk measurement techniques in real estate lending may be less developed than in other credit risk instruments. In addition, various policy recommendations for prudential regulators are made. [source] Interlaboratory validation of oxidation-index measurement methods for UHMWPE after long-term shelf agingJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2002S. M. Kurtz Abstract An international oxidation index standard would greatly benefit the orthopedic community by providing a universal scale for reporting oxidation data of ultra-high molecular weight polyethylene (UHMWPE). We investigated whether severe oxidation associated with long-term shelf aging affects the repeatability and reproducibility of area-based oxidation index measurement techniques based on normalization with the use of 1370- or 2022-cm,1 infrared (IR) absorption reference peaks. Because an oxidation index is expected to be independent of sample thickness, subsurface oxidation was examined with the use of both 100- and 200-,m-thick sections from tibial components (compression-molded GUR 1120, gamma irradiated in air) that were shelf aged for up to 11.5 years. Eight institutions in the United States and Europe participated in the present study, which was administered in accordance with ASTM E691. On average, the 100-,m-thick samples were associated with significantly greater interlaboratory relative standard uncertainty (40.3%) when compared with the 200-,m samples (21.8%, p = 0.002). In contrast, the intralaboratory relative standard uncertainty was not significantly affected by the sample thickness (p = 0.21). The oxidation index method did not significantly influence either the interlaboratory or intralaboratory relative standard uncertainty (p = 0.32 or 0.75, respectively). Our interlaboratory data suggest that with the suitable choice of specimen thickness (e.g., 200 ,m) and either of the two optimal oxidation index methods, interlaboratory reproducibility of the most heavily oxidized regions in long-term shelf-aged components can be quantified with a relative standard uncertainty of 21% or less. Therefore, both the 1370-cm,1 and the 2022-cm,1 reference peaks appear equally suitable for use in defining a standard method for calculating an oxidation index for UHMWPE. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 15,23, 2002 [source] Techniques for oxygen transfer measurement in bioreactors: a reviewJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2009S Suresh Abstract Oxygen is the most essential requirement for aerobic bioprocesses. The microbial growth in a bioreactor depends upon the oxygen transfer rate (OTR). The OTR is widely used to study the growth behavior of microbial and plant cell cultures. The mass transfer coefficient (kLa) determines the magnitude of the OTR. There are many techniques for measuring oxygen concentration and OTR in bioreactors. Zirconia, electrochemical, infrared, ultrasonic and laser cells are used to measure oxygen concentration in the liquid medium. Optical sensors are better alternatives to measure oxygen concentration in small bioreactors. Sulfite oxidation and gassing-out methods with a Clark-type electrode have been used for OTR measurements in bioreactors. Many new novel techniques have evolved recently for intermittent and continuous online measurement of OTR/kLa in various types of bioreactors. The present paper gives an overview of various measurement techniques and their limitations and/or suitability for measurement of OTR/kLa in various kinds of bioreactors, especially small bioreactors. Copyright © 2009 Society of Chemical Industry [source] Common components and specific weight analysis and multiple co-inertia analysis applied to the coupling of several measurement techniquesJOURNAL OF CHEMOMETRICS, Issue 5 2006M. Hanafi Abstract The present paper compares two multiblock techniques: the Common Components and Specific Weights Analysis (CCSWA) and the Multiple Co-inertia Analysis (MCoA). Both methods are used to (1) to investigate the relationships among various data tables and (2) to extract latent variables from information of different nature, reflecting different facets of a food product. Our objective is to study the ability of these methods to extract, from a set of data tables, latent characteristics which are representative of the whole modifications brought to a complex system (food product) by a modification of a given process factor. The comparison of these methods is based on the investigation of their conceptual framework by particularly highlighting new properties of CCSWA. Moreover, the two techniques of analysis are compared on the basis of a case study in cheese processing where each cheese sample is described by different kinds of measurements. Copyright © 2007 John Wiley & Sons, Ltd. [source] Accelerating the analyses of 3-way and 4-way PARAFAC models utilizing multi-dimensional wavelet compressionJOURNAL OF CHEMOMETRICS, Issue 11-12 2005Jeff Cramer Abstract Parallel factor analysis (PARAFAC) is one of the most popular methods for evaluating multi-way data sets, such as those typically acquired by hyphenated measurement techniques. One of the reasons for PARAFAC popularity is the ability to extract directly interpretable chemometric models with little a priori information and the capability to handle unknown interferents and missing values. However, PARAFAC requires long computation times that often prohibit sufficiently fast analyses for applications such as online sensing. An additional challenge faced by PARAFAC users is the handling and storage of very large, high-dimensional data sets. Accelerating computations and reducing storage requirements in multi-way analyses are the topics of this manuscript. This study introduces a data pre-processing method based on multi-dimensional wavelet transforms (WTs), which enables highly efficient data compression applied prior to data evaluation. Because multi-dimensional WTs are linear, the intrinsic underlying linear data construction is preserved in the wavelet domain. In almost all studied examples, computation times for analyzing the much smaller, compressed data sets could be reduced so much that the additional effort for wavelet compression was more than recompensated. For 3-way and 4-way synthetic and experimental data sets, acceleration factors up to 50 have been achieved; these data sets could be compressed down to a few per cent of the original size. Despite the high compression, accurate and interpretable models were derived, which are in good agreement with conventionally determined PARAFAC models. This study also found that the wavelet type used for compression is an important factor determining acceleration factors, data compression ratios and model quality. Copyright © 2006 John Wiley & Sons, Ltd. [source] Rapid saliva processing techniques for near real-time analysis of salivary steroids and proteinJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 6 2008Kelly R. Atkinson Abstract Introduction: Point-of-care (POC) measurements using saliva samples have immense potential to assess systemic health and wellbeing, but sample viscosity and contaminants can affect analyses. We sought a portable clean-up method for whole saliva appropriate for use with POC measurement techniques such as biosensors. Methods: Whole saliva from each of 13 male subjects was split into 5 fractions. Each fraction was treated with a different clean-up process: a freeze,thaw,centrifuge (FTC) step; centrifugation alone; or passage through a Mini-UniPrep polyethersulfone filter, cotton Salivette®, or foam Oracol device. Following clean-up, each subject's treated saliva fractions were assayed for cortisol, testosterone, dehydroepiandrosterone (DHEA), and proteinconcentrations. The effects of clean-upmethods on nonspecific binding (NSB) in a biosensor were also assessed. Results: Compared with FTC, no analytes were affected by centrifugation alone. Cotton Salivettes significantly altered all analytes, with increases in cortisol (+64%), testosterone (+126%), and DHEA (off-scale) levels, and decreased protein (,21%) and biosensor NSB (,75%). Oracol foam devices decreased DHEA levels by 28%. Mini-UniPrep filtration decreased testosterone (,45%) and DHEA (,66%) concentrations while increasing cortisol (+40%). Conclusion: No method was optimal for all analytes, highlighting the need for validation of saliva treatment methods before their adoption in rapid POC analyses. J. Clin. Lab. Anal. 22:395,402, 2008. © 2008 Wiley-Liss, Inc. [source] "Chips with Everything": A Laboratory Exercise for Comparing Subjective and Objective Measurements of Potato ChipsJOURNAL OF FOOD SCIENCE EDUCATION, Issue 3 2005Cathy Davies ABSTRACT: The following laboratory exercise was designed to aid student understanding of the differences between subjective and objective measurements. Students assess the color and texture of different varieties of potato chip (crisps) by means of an intensity rating scale and a rank test and objectively with a colorimeter and texture analyzer. For data analysis, student are instructed to critically determine, using basic statistics, any differences between the subjective and objective measurement techniques. This laboratory exercise is very versatile, and although it is designed as a hands-on exercise in an undergraduate Food Analysis course, it has also been a demonstration for High School students. [source] Repeatability of T1-quantification in dGEMRIC for three different acquisition techniques: Two-dimensional inversion recovery, three-dimensional look locker, and three-dimensional variable flip angleJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2010Carl Siversson MS Abstract Purpose: To evaluate the repeatability of the dGEMRIC (delayed gadolinium enhanced MRI of cartilage) method in osteoarthritis-prone knee joints for three different T1 quantification techniques: two-dimensional inversion recovery (2D-IR), three-dimensional Look-Locker (3D-LL), and three-dimensional variable flip angle (3D-VFA). Materials and Methods: Nine subjects were examined twice, with a 2-week interval, using all three measurement techniques. Four regions of interest were defined in the central medial and lateral femoral cartilage. The repeatability was evaluated for each measurement technique. For the 3D techniques, the variation between different slices was also evaluated. Results: Repeatability expressed by root-mean-square coefficient of variation (CVRMS) showed similar results for 2D-IR and 3D-LL (5.4,8.4%). For 3D-VFA CVRMS was higher (9.3,15.2%). Intraclass correlation coefficient showed both 2D-IR and 3D-LL reliability to be moderate, while 3D-VFA reliability was low. Inter-slice CVRMS and ICC was of the same magnitude as the repeatability. No clear differences could be interpreted between the condyles. Conclusion: Both 2D-IR and 3D-LL perform well in generating repeatable dGEMRIC results, while 3D-VFA results are somewhat inferior. Furthermore, repeatability results in this study are similar to previously published results for healthy subjects. Finally, the positioning of the analyzed images is crucial to generate reliable repeatability results. J. Magn. Reson. Imaging 2010;31:1203,1209. © 2010 Wiley-Liss, Inc. [source] Summary findings of the fourth international radiocarbon intercomparison (FIRI)(1998,2001)JOURNAL OF QUATERNARY SCIENCE, Issue 7 2002Elisabetta Boaretto Abstract Interlaboratory comparisons have been widely used in applied radiocarbon science. These are an important part of ongoing quality assurance (QA) programmes, which are vital to the appropriate interpretation of the evidence provided by the 14C record in Quaternary applications (including climate change and environmental reconstruction). International comparisons of laboratory performance are an essential component of the quality assurance process in radiocarbon dating. If the user community is to have confidence in radiocarbon results, it needs to be assured that laboratories world wide are producing measurements that are reliable and in accordance with ,good practice'. The findings from the most recent (completed in 2001) and extensive (more than 90 participating laboratories) radiocarbon intercomparison (FIRI) are reported here. This study was designed (i) to assess comparability, or otherwise, of the results from different laboratories and (ii) to quantify the extent and possible causes of any interlaboratory variation. The results demonstrate that there are no significant differences amongst the main measurement techniques (gas proportional counting, liquid scintillation counting and accelerator mass spectrometry (AMS)) but there is evidence of small laboratory offsets relative to known age samples for some laboratories. There is also evidence in some cases of underestimation of measurement precision. Approximately 10% of all results were classified as extreme (outliers) and these results were generated by 14% of the laboratories. Overall, the evidence supports the fact that radiocarbon laboratories are generally accurate and precise but that, notwithstanding internal QA procedures, some problems still occur, which can best be detected by participation in independent intercomparisons such as FIRI, where the results allow individual laboratories to assess their performance and to take remedial measures where necessary. The results from FIRI are significant in that they show a broad measure of agreement between measurements made in different laboratories on a wide range of materials and they also demonstrate no statistically significant difference between measurements made by radiometric or AMS techniques. Copyright © 2002 John Wiley & Sons, Ltd. [source] Solubility of Silver and Palladium in BaTiO3JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2004Shao-Ju Shih Silver, palladium, and their alloys are frequently used as electrode materials for BaTiO3 (BT) based dielectrics. However, the electrodes and dielectrics usually are cofired at high temperatures, and silver and palladium can dissolve into the BT during cofiring. In the present study, the solubility of silver and palladium into BT after cofiring was determined. Three measurement techniques were used to determine solubility: chemical analysis, structural analysis, and dielectric analysis. The solubility of the silver in the BT was low, 450 ppm, after cofiring at 1290°C for 2 h in air. The diffusion distance of the silver ions into the BT was >5 ,m. The solubility of the palladium in the BT was even lower, 50 ppm at 1290°C, and the diffusion distance was ,1 ,m. The solubility of both the silver and the palladium in the BT decreased as the oxygen partial pressure of the sintering atmosphere decreased. These results demonstrated that both silver and palladium solutes act as acceptors for BT. [source] Review article: 5-aminosalicylate formulations for the treatment of ulcerative colitis , methods of comparing release rates and delivery of 5-aminosalicylate to the colonic mucosaALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 6 2008G. R. LICHTENSTEIN Summary Background, Many oral 5-aminosalicylic acid (5-ASA) formulations are designed to maximize 5-ASA release in the colon where it acts topically on the colonic mucosa. Delayed-release formulations and azo-prodrugs minimize 5-ASA absorption in the upper gastrointestinal (GI) tract. Aims, To review methods for assessing 5-ASA release and colonic distribution from oral formulations, and the potential use of this information for guiding clinical decisions. Methods, PubMed and recent conference abstracts were searched for articles describing techniques used to assess 5-ASA release from ulcerative colitis (UC) therapies. Results, In-vitro GI models, although unable to simulate more complex aspects of GI physiology, can provide useful data on 5-ASA release kinetics and bioaccessibility. Gamma-scintigraphy is useful for investigating GI disintegration of different formulations, but may not accurately reflect 5-ASA distribution. Plasma pharmacokinetic studies provide data on systemic exposure, but not on colonic distribution or mucosal uptake. Mucosal biopsies provide direct evidence of colonic distribution and may predict clinical efficacy, but must be interpreted cautiously because of considerable inter-subject variability and other confounding factors. Conclusion, While assessment of 5-ASA release is important, limitations of individual measurement techniques mean that randomized clinical studies in UC patients remain the best guide for dosing and treatment regimen decisions. [source] Local electrochemical properties of laser beam-welded high-strength Al,Zn,Mg,Cu alloysMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 1 2008J. Wloka Butt welds of two high-strength Al,Zn,Mg,Cu alloys with different zinc contents were welded by a laser beam welding technique. Due to the high energy density of the laser beam, the microstructural changes are confined to very thin regions. Electrochemical properties of the weld heat-affected zones are investigated by local electrochemical measurement techniques and correlated with microhardness measurements, macroscopic corrosion behaviour and metallographic sections. It turned out that microelectrochemical techniques, especially the EC-pen is a versatile and easy to handle tool for the resolution of changes in the electrochemical properties across a weld bead. It unveils modifications, which cannot be resolved by hardness measurements. By microcell measurements, local corrosion kinetics can be estimated. [source] Rater and occasion impacts on the reliability of pre-admission assessmentsMEDICAL EDUCATION, Issue 12 2009Rick D Axelson Context, Some medical schools have recently replaced the medical school pre-admission interview (MSPI) with the multiple mini-interview (MMI), which utilises objective structured clinical examination (OSCE)-style measurement techniques. Their motivation for doing so stems from the superior reliabilities obtained with the OSCE-style measures. Other institutions, however, are hesitant to embrace the MMI format because of the time and costs involved in restructuring recruitment and admission procedures. Objectives, To shed light on the aetiology of the MMI's increased reliability and to explore the potential of an alternative, lower-cost interview format, this study examined the relative contributions of two facets (raters, occasions) to interview score reliability. Methods, Institutional review board approval was obtained to conduct a study of all students who completed one or more MSPIs at a large Midwestern medical college during 2003,2007. Within this dataset, we identified 168 applicants who were interviewed twice in consecutive years and thus provided the requisite data for generalisability (G) and decision (D) studies examining these issues. Results, Increasing the number of interview occasions contributed much more to score reliability than did increasing the number of raters. Conclusions, Replicating a number of interviews, each with one rater, is likely to be superior to the often recommended panel interview approach and may offer a practical, low-cost method for enhancing MSPI reliability. Whether such a method will ultimately enhance MSPI validity warrants further investigation. [source] Structured review of enamel erosion literature (1980,1998): a critical appraisal of experimental, clinical and review publicationsORAL DISEASES, Issue 4 2000G. Maupome OBJECTIVE: To attain an objective account of the methods to measure enamel erosion used in 1980,1998 publications, a structured review of the literature was undertaken. METHODS: Inclusion and exclusion criteria were applied to 731 clinical/experimental research and review reportS. Eighty-five included papers were subsequently rated according to ,hierarchy of evidence' guidelines to assess the strength of the report's design and the relevance of the evidence to replicating enamel erosion in vivo in humanS. Scores were assigned to rate each aspect in the guidelines. RESULTS: A total of 16 clinical, 13 review and 56 experimental papers were assessed; 36.4% were published during 1996,1998.Excluding reviews, 16 papers were qualitative and 56 quantitative; 51 used human enamel. Our classification yielded nine groups of methods (five scoring systems and 26 measurement techniques).CTFPHE (Can Med Assoc J 1992; 147: 443) grading of research reports indicated that 2.8% provided evidence grade I; 20.8%, grade IIa; 63.9%, grade III; and 12.5%, grade IV. CONCLUSIONS: There has been a consistent increase in the body of knowledge. The overall quality of publications has not substantially changed over time. Experimental studies were more often quantitative, and quantitative studies had better research designS. No single group of research methods had obviously superior research designs. [source] Exploring the third dimension in root resorptionORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 2 2004EKM Chan Structured Abstract Authors , Chan EKM, Darendeliler MA Objective , To review and investigate the validity of various 2D quantitative measurement techniques, and to explore the third dimension of root resorption. Design , A review of the literature involving various quantitative evaluation of root resorption. Results , Quantitative evaluation of resorption using radiographs has proven to be highly inaccurate because of magnification errors and their inability to be readily repeated and reproduced. Studies using histology sections of samples have proven to be laborious and technique sensitive. Inherent parallax errors and loss of material in data transfer have denied the true understanding of this 3D event. Conclusion , With the evolution in computing technology and digital imaging, the vision of evaluating the extent of root resorption in 3D has materialized. It was demonstrated that 3D volumetric quantitative evaluation of root resorption craters was feasible and its accuracy and repeatability was high. [source] Microsystems for Optical Cell Detection: Near versus Far FieldPARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 1 2008Stefan Kostner Abstract Optical flow cytometry is a process where physical and (bio-) chemical parameters of single biological cells can be obtained in a flow-through setup by optical measurement techniques. Unlike conventional systems, where measurements are conducted in the optical far field, the proposed system senses the cell's optical projection in the near field by using integrated photodiodes. This allows for the attainment of additional parameters, e.g., size and shape, which are usually hidden in the far field. In addition, parameters such as refractive index and absorption of the cell influence the sensor signal. Additionally, with another setup, a different approach is followed to measure similar parameters with external detection using a DVD laser pickup head and a microchannel equipped with a mirror. This low-cost setup does not measure in the near field, and therefore, is dedicated to different parameters. In this contribution, results from measurements with polystyrene particles and biological cells (yeast and Chinese hamster ovary) are presented and the advantages and limitations of both systems are outlined. [source] The measurement and importance of red cell survivalAMERICAN JOURNAL OF HEMATOLOGY, Issue 2 2009Robert S. Franco The measurement of red blood cell survival in the circulation has progressed from the original differential agglutination technique of Ashby to current isotopic and flow cytometric methods. While occasionally useful in the clinic, these methods find widespread use in a number of important research areas, including the evaluation of new red cell storage media in transfusion medicine and studies of the pathophysiology of sickle cell disease and diabetes. In this review, measurement techniques are placed in historical perspective and examined for relative merits and suitable application. Am. J. Hematol., 2009. © 2008 Wiley-Liss, Inc. [source] Optical, structural, and electrical properties of Cu2O thin filmsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2010Ferid Chaffar Akkari Abstract Glancing-angle deposition (GLAD) was used in this work to grow transparent oxide Cu2O thin films by annealing in air at 185,°C of copper films deposited firstly by this method onto glass substrates. The annealing temperature of 185,°C corresponds to the optimal temperature that corresponds to the formation of Cu2O phase. The copper was sculptured into a zigzag shape, which present case (i) one column with inclined angle ,, case (ii) two columns with inclined angles , and ,,, and case (iii) three copper inclined columns with inclined angles ,, ,,, and , where , is the deposition angle between the incident flux and the substrate surface normal. The films after annealing have thicknesses of 165, 185, and 265,nm for cases (i), (ii), and (iii), respectively. The air-annealed copper films were characterized for their structural, surface morphological; electrical and optical properties by using X-ray diffraction (XRD), scanning electron microscopy (SEM), electrical resistivity, and optical (transmittance and reflectance) measurement techniques. Optical studies show a direct allowed transition around 2.5,eV for the three cases. High absorptions coefficients in the range 2,×,105,3.7,×,106,cm,1 were found for photon energies higher than 2.7,eV. The Cu2O films exhibit in cases (i) and (ii) p-type conductivity but in case (iii) the Cu2O films exhibit n-type conductivity. [source] Studies on structural and optical properties of Cu-Sb-O thin filmsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2010Nadia Chaglabou Abstract We report in this paper the structural and optical properties of Cu-Sb-O thin films systems. Samples were prepared via sequential thermal vacuum deposition of Cu and Sb or Sb and Cu (10 -5 Torr) on glass substrates after what they were heated in vacuum at 200 °C for 1 hour. So, the obtained intermetallic multilayer systems (Cu/Sb)j=1,2,3 and (Sb/Cu)j=1,2,3 were annealed in air atmosphere between 30°C and 400 °C for 3 h for j=1; for 6 h for j=2 and for 9 h for j=3. These films were characterized for their structural, surface morphological, compositional, and optical properties by using X-ray diffraction (XRD) and optical (transmittance and reflectance) measurement techniques. The X-ray diffraction (XRD) patterns revealed the presence of CuO, Sb2O3 and Sb2O4phases. The absorption coefficient of Cu-Sb-O thin films in all cases is in the range104 -105 cm -1. The films after annealing have two direct band gap energies in the ranges 1.48,1.50 eV and 2.20-2.95 eV. The electrical measurements show a conversion from a metallic phase to the semiconductor phase after annealing. The samples exhibit p-type conductivity after annealing in air of the intermetallic multilayer systems (Cu/Sb)j=3 and (Sb/Cu)j=3. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Procedural considerations for photographic-based joint angle measurementsPHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 4 2005Colin Dunlevy Abstract Background and Purpose Measuring static joint angles is important to clinicians involved in assessing, diagnosing and treating musculoskeletal disorders. Ne measurement techniques such as the Uillinn Method © (UM) employ the relatively new technology of digital photography and software to form a virtual goniometer. It is of central importance that the errors associated such new measurement techniques are known. Precision in joint angle measurement is a challenge and errors can arise from three separate categories: equipment error, examiner error or biological error. The aim of the present study was to discover the amount of equipment error associated with the UM and to present guidelines for the optimal use of a photographic based measurement technique Method This was a non-clinical agreement study design that attempted to describe the best possible agreement between a mathematical control dataset and the angles calculated from the virtual goniometer, which in this case was the UM. When this was established, the effect of rotation and placing the angle at the periphery of the camera's field of view were tested. Results The repeatability coefficient (RC) between the UM and the control data under optimal conditions was 0.81°; the typical error (TE) was 0.29° (n = 120). When the angle appeared at the edge of the photograph the RC increased to 2° and the TE to 0.73° (n = 48). When 5° rotation was introduced between the camera and the angle no increase in error was detected. However, increasing amounts of rotation above 5° was proportional to increases in the RC (RC at 10° = 2.3°; 20° = 3.86°; 30° = 14.8°; 40° = 27.27°) and the TE (TE at 10° = 0.83°; 20° = 2.7°; 30° = 5.3°; 40° = 9.8°) scores. Conclusion Photographic-based joint angle measurement techniques are subject to error if careful procedures are not observed. Best procedures include photography from a perpendicular viewpoint and centring the lens on the target angle. Copyright © 2005 John Wiley & Sons, Ltd. [source] The Secret Lives of Liberals and Conservatives: Personality Profiles, Interaction Styles, and the Things They Leave BehindPOLITICAL PSYCHOLOGY, Issue 6 2008Dana R. Carney Although skeptics continue to doubt that most people are "ideological," evidence suggests that meaningful left-right differences do exist and that they may be rooted in basic personality dispositions, that is, relatively stable individual differences in psychological needs, motives, and orientations toward the world. Seventy-five years of theory and research on personality and political orientation has produced a long list of dispositions, traits, and behaviors. Applying a theory of ideology as motivated social cognition and a "Big Five" framework, we find that two traits, Openness to New Experiences and Conscientiousness, parsimoniously capture many of the ways in which individual differences underlying political orientation have been conceptualized. In three studies we investigate the relationship between personality and political orientation using multiple domains and measurement techniques, including: self-reported personality assessment; nonverbal behavior in the context of social interaction; and personal possessions and the characteristics of living and working spaces. We obtained consistent and converging evidence that personality differences between liberals and conservatives are robust, replicable, and behaviorally significant, especially with respect to social (vs. economic) dimensions of ideology. In general, liberals are more open-minded, creative, curious, and novelty seeking, whereas conservatives are more orderly, conventional, and better organized. [source] | ||||||||||||||||||||||||||||||||||