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Validation

Distribution by Scientific Domains
Medical Sciences38%
Chemistry20%
Life Sciences11%
Engineering11%
Earth and Environmental Science4%
Psychology3%
Business, Economics, Finance and Accounting2%
Polymers and Materials Science2%
5 Other Domains9%
Distribution within Medical Sciences
Neurology5%
78 Other Subdomains85%

Kinds of Validation

  • and validation
  • bioanalytical method validation
  • clinical validation
  • construct validation
  • cross validation
  • cross-cultural validation
  • empirical validation
  • experimental validation
    		•
  • extensive validation
  • external validation
  • field validation
  • functional validation
  • initial validation
  • internal validation
  • leave-one-out cross validation
  • marker validation
    		•
  • method validation
  • model validation
  • numerical validation
  • preliminary validation
  • prospective validation
  • psychometric validation
  • quantitative validation
  • statistical validation
    		•
  • structure validation
  • target validation
  • testing and validation
  • vivo validation

    • Terms modified by Validation

  • validation analysis
  • validation cohort
  • validation criterioN
  • validation data
  • validation data set
  • validation dataset
  • validation experiment
    		•
  • validation group
  • validation method
  • validation methods
  • validation parameter
  • validation period
  • validation procedure
  • validation process
    		•
  • validation protocol
  • validation purpose
  • validation result
  • validation sample
  • validation set
  • validation strategy
  • validation studies
    		•
  • validation study
  • validation techniques
  • validation test
  • validation trials

    • Selected Abstracts

    DEVELOPMENT AND VALIDATION OF A NEW FACILITY FOR LOW EARTH ORBIT THERMAL CYCLING SIMULATION

    EXPERIMENTAL TECHNIQUES, Issue 5 2009
    P. Micciché
    First page of article [source]

    BIOLOGICAL VALIDATION OF TOMATO PULP CONTINUOUS HEAT PROCESS

    JOURNAL OF FOOD PROCESS ENGINEERING, Issue 6 2004
    CRISTIANA DE PAULA PACHECO
    ABSTRACT This research validated the commercial process applied to tomato pulp (pH 4.3 and 8 Brix) packed in Tetra Brik packages. Spores of Bacillus coagulans and Neosartorya fischeri were selected as targets. The heat resistance of both microorganisms, tested independently, was compared. The redesigned thermal processes were carried out in a aseptic processing and tested by indirect inoculation and retrieval with spores immobilized in alginate/tomato balls. The results showed that processes for 30 s at 115C or greater did not allow the survival of heat-resistant molds. For bacterial spores, processes for 30 s at 109C or greater showed no survivors. Although, 30 s at 115C will control both types of spoilage spores, concern for possible C. botulinum growth attributed to metabiosis in product with varying initial populations of molds and residual oxygen content dictated, a process recommendation of 60 s at 126C for safety reasons. [source]

    VALIDATION OF PATHOGEN DESTRUCTION DURING MANUFACTURE OF A MEAT-BASED POTATO SNACK (CHIPAROO)

    JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 6 2003
    S. J. KIERAS
    ABSTRACT A Chiparoo is a comminuted rabbit and sweet potato dehydrated snack chip manufactured using a process suitable for underdeveloped regions of the world. The purpose of this study was to evaluate the ability of the Chiparoo manufacturing process to adequately deliver 5 log reductions in Listeria monocytogenes, Escherichia coli O157:H7, Salmonella typhimurium, and Staphylococcus aureus per gram of food product. These four pathogens were inoculated into regular (pH , 6.0) and lime juice added (pH , 5.0) formulations of rabbit and sweet potato Chiparoos. They were inoculated as a cocktail of four microorganisms at concentrations of approximately 106/g of each pathogen. Individual inoculations of each pathogen at the same concentration (106/g) were also prepared. After inoculation, the product was held for 5 h at 37C, to simulate the maximum hold time in a sub-Saharan Africa manufacturing facility, then dehydrated at 55C (+/- 5C) for 9 h. Samples of the product were taken during the hold and dehydration steps, decimally diluted and plated on the appropriate enumeration medium. The regular formulation (pH , 6.0) did not achieve the required 5 log reduction of each of the four pathogens, while the lime juice added formulation (pH , 5.0) achieved the desired minimum 5 log reduction for each of the four foodborne pathogens tested. [source]

    DESIGN, CONSTRUCTION AND VALIDATION OF A SANITARY GLOVE BOX PACKAGING SYSTEM FOR PRODUCT SHELF-LIFE STUDIES

    JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 3 2001
    ZEHRA AYHAN
    A glove box has been constructed as pan of an integrated pilot plant scale pulsed electric field processing and packaging system to facilitate studies of product shelf-life with selected packaging materials. The glove box was sanitized using combination of hydrogen peroxide and germicidal UV light. A HEPA air filter provided positive pressure of bacteria-free air. Nonselective nutrient broth was sterilized and filled into presanitized bottles inside the glove box. Negative and positive controls were included in the experiment. All bottles were incubated at 22C and 37C for two weeks and checked for rnicrobial growth by measuring optical density at 600 nm using a spectrophotometer and by plating on plate count agar and potato dextrose agar for total aerobic and, yeast and mold counts, respectively. No turbidity or microbial growth was observed in the media filled in the sanitized bottles using the sanitized glove box at 22 and 37C. PEF processed orange juice using this system had a shelf-life of more than 16 weeks at 4C. [source]

    TRAINING, VALIDATION AND MAINTENANCE OF A PANEL TO EVALUATE THE TEXTURE OF DRY BEANS (PHASEOLUS VULGARIS L.)

    JOURNAL OF SENSORY STUDIES, Issue 3 2008
    R. ROMERO DEL CASTILLO
    ABSTRACT The inclusion of dry beans in diets has clear health benefits. However, consumers in developed countries mainly choose beans for their sensory qualities, especially for their texture. This article describes the constitution, training and validation of a panel of judges to evaluate the texture of dry beans. The judges were trained in the perception of different textures, analyzed a wide range of beans and selected seed-coat roughness, seed-coat perceptibility and creaminess/mealiness of the cotyledon as the main attributes to be scored. After training, the panel was capable of discriminating between different varieties of beans and even between beans of the same variety grown at different locations. The analysis of the behavior of the panel in a standard tasting session 2 years after its formation showed that periodic inclusion of samples from the extremes of the scales for the attributes during tasting sessions was sufficient to keep the panel trained. PRACTICAL APPLICATIONS This article could serve as a guide for the training of sensory panels to evaluate the texture of dry beans. It describes the selection of the attributes on which the analysis is based, references for the extreme values of the attributes and how to train the panel. It also provides a practical example of the analysis of the behavior of the panel some time after training. [source]

    CROSS VALIDATION OF A SENSORY LANGUAGE FOR CHEDDAR CHEESE

    JOURNAL OF SENSORY STUDIES, Issue 3 2002
    M.A. DRAKE
    ABSTRACT Communication and replication of sensory data from different sites are important to track progress on fundamental research issues and to ensure that research efforts are not duplicated. A uniform anchored Cheddar cheese sensory language has previously been identified and refined. The objective of this study was to demonstrate application of the defined sensory language for Cheddar cheese for communication between sensory panels at three different sites. The defined and referenced sensory language for Cheddar cheese was disseminated to panel leaders at the three sites and sensory panels (n , 8) were trained for 40 to 80 h at each site. Ten forty-pound blocks of Cheddar cheese representing different ages were collected and evaluated by the panels. Cheeses were differentiated by the three panels by univariate and multivariate analysis (P<0.05). Cheeses were differentiated by the three panels in a similar manner. Results indicate that it is possible to calibrate panels using a standardized defined sensory language. [source]

    Architectural Methodology Based on Intentional Configuration of Behaviors

    COMPUTATIONAL INTELLIGENCE, Issue 1 2001
    François Michaud
    Intelligence has been an object of study for a long time. Different architectures try to capture and reproduce these aspects into artificial systems (or agents), but there is still no agreement on how to integrate them into a general framework. With this objective in mind, we propose an architectural methodology based on the idea of intentional configuration of behaviors. Behavior-producing modules are used as basic control components that are selected and modified dynamically according to the intentions of the agent. These intentions are influenced by the situation perceived, knowledge about the world, and internal variables that monitor the state of the agent. The architectural methodology preserves the emergence of functionality associated with the behavior-based paradigm in the more abstract levels involved in configuring the behaviors. Validation of this architecture is done using a simulated world for mobile robots, in which the agent must deal with various goals such as managing its energy and its well-being, finding targets, and acquiring knowledge about its environment. Fuzzy logic, a topologic map learning algorithm, and activation variables with a propagation mechanism are used to implement the architecture for this agent. [source]

    Validation and Clinical Utility of a Simple In-Home Testing Tool for Sleep-Disordered Breathing and Arrhythmias in Heart Failure: Results of the Sleep Events, Arrhythmias, and Respiratory Analysis in Congestive Heart Failure (SEARCH) Study

    CONGESTIVE HEART FAILURE, Issue 5 2006
    William T. Abraham MD
    Fifty patients with New York Heart Association class III systolic heart failure were enrolled in this prospective multicenter study that compared the diagnostic accuracy of a home-based cardiorespiratory testing system with standard attended polysomnography. Patients underwent at least 2 nights of evaluation and were scored by blinded observers. At diagnostic cutoff points of ,5, ,10, and ,15 events per hour for respiratory disturbance severity, polysomnography demonstrated a sleep-disordered breathing prevalence of 69%, 59%, and 49%, respectively. Compared with polysomnography, the cardiorespiratory testing system demonstrated predictive accuracies of 73%, 73%, and 75%, which improved to 87%, 87%, and 83%, respectively, when analysis of covariance suggested reanalysis omitting one site's data. The system accurately identified both suspected and unsuspected arrhythmias. The device was judged by 80% of patients to be easy or very easy to use, and 74% of patients expressed a preference for the in-home system. Therefore, this system represents a reasonable home testing device in these patients. [source]

    Total nucleated cell differential for blood and bone marrow using a single tube in a five-color flow cytometer,,

    CYTOMETRY, Issue 2 2008
    Sven Björnsson
    Abstract Background: Flow cytometry allows the use of several antibodies in addition to light scatter, and most flow cytometers will provide at least seven measurements on each cell passing through the laser beam. A skilled microscopist will classify at least 14 cell classes in bone marrow or blood. Our goal was to use the seven parameters available in our flow cytometer to provide a reliable differential count using only one tube. Methods: Peripheral blood samples were analyzed on the Beckman Coulter LH750 cell counter, and the flagging and messages from the cell counter were used to select normal or pathological samples. Samples without flags (N = 50), with >2% erythroblasts (N = 80), or with "Blast" or "Verify diff" flags (N = 54) were investigated. We used a lyse-no-wash method to ensure minimal loss of fragile cells with live gating on DRAQ5-positive cells to acquire only nucleated cells. The FL-1 to FL-4 channels were used for the antibodies CD36-FITC, CD203-PE, CD138-PE, CD45-ECD, CD16-Pcy5, and CD56-Pcy5. FL-5 was used for the DNA-stain DRAQ5. Results: Using live gate acquisition on DRAQ5, we were able to classify total nucleated cells into 10 classes. We were unable to identify megakaryocytes, but platelets could be studied by rerunning the sample after dilution and gating on DRAQ5-negative CD36-posive events. Validation against digitized microscopy and cell counter showed linear correlations within each cell class with correlation coefficients that seem reasonable for cellular classification. The lowest correlation was found for basophil granulocytes. Flow cytometry detected twice as many immature neutrophils compared to microscopy. Conclusions: We have designed a one-tube immunophenotyping panel for classification of total nucleated cells and platelets in blood or bone marrow. The seven parameters available in one single tube in our cytometer seem to be enough for reliable differential count even in difficult pathological samples. The analytical imprecision of the flow cytometer differential was much lower than that obtained with microscopy or cell counter differentials. © 2007 Clinical Cytometry Society. [source]

    Validation of the Depression and Somatic Symptoms Scale by comparison with the Short Form 36 scale among psychiatric outpatients with major depressive disorder

    DEPRESSION AND ANXIETY, Issue 6 2009
    Ching-I Hung M.D.
    Abstract Background: The Depression and Somatic Symptoms Scale (DSSS) is a self-administered scale developed for monitoring both depression and somatic symptoms. The aims of this study were to establish the criterion-related validity of the DSSS by testing the correlation between the DSSS and the Short Form 36 (SF-36) scale and to compare the ability of the DSSS and two other scales in predicting the outcome of the SF-36. Methods: The study enrolled 135 outpatients with a major depressive episode, 95 of whom received treatment for 1 month. Four scales were administered and evaluated: the DSSS, the SF-36, the Hospital Anxiety and Depression Scale, and the Hamilton Depression Rating Scale. Pearson correlation was used to test correlations among scales. Multiple linear regressions were used to find the scales most effective in predicting the SF-36. Results: The three scales were significantly correlated with most of the SF-36 subscales. The depression and somatic subscales of the DSSS significantly correlated with the mental and physical subscales of the SF-36, respectively. The DSSS and the Hospital Anxiety and Depression Scale were better able to predict physical and mental subscales of the SF-36, respectively. The Hamilton Depression Rating Scale had a good ability to predict functional impairment. Conclusions: Psychometric scales with appropriate somatic symptoms might be more compatible with both physical and mental dimensions of the SF-36. DSSS proved to be a valid scale for monitoring both depression and somatic symptoms in patients with depression. Future studies should test whether the DSSS is better at predicting the treatment and prognosis of depression than conventional scales for depression. Depression and Anxiety, 2009. © 2009 Wiley-Liss, Inc. [source]

    Validation of an algorithm combining haemoglobin A1c and fasting plasma glucose for diagnosis of diabetes mellitus in UK and Australian populations

    DIABETIC MEDICINE, Issue 2 2009
    S. E. Manley
    Abstract Aim, To determine whether glycated haemoglobin (HbA1c) can be used in combination with fasting plasma glucose (FPG) for the diagnosis of diabetes in patients with impaired fasting glucose (IFG) and in a broader spectrum of patients. Methods, An algorithm was derived from oral glucose tolerance test (OGTT) capillary samples in 500 consecutive UK patients with IFG by World Health Organization criteria. It was validated in a further 500 UK patients and, with venous specimens, in 1175 unselected Australian patients. Results, The derivation cohort was aged 61 years (50,69 years) (median IQ range) with 52% male and 12% South Asian. Diabetes Control and Complications Trial-aligned HbA1c was 6.2% (5.8,6.6%) (reference interval < 6.0%) and FPG 6.7 mmol/l (6.3,7.2 mmol/l). FPG was in the diabetes range in 36% of patients, with an OGTT identifying a further 12% with diabetes. The derived algorithm, (HbA1c , 6.0% with FPG < 7.0 mmol/l) identified those patients requiring an OGTT to diagnose diabetes. When applied to the UK validation cohort, sensitivity was 97% and specificity 100%. The algorithm was equally effective in the unselected group, aged 59 years (49,68 years) and 54% male, with sensitivity 93% and specificity 100%. HbA1c was 6.0% (5.6,6.6%) and FPG 6.0 mmol/l (5.3,6.8 mmol/l), with 26% having IFG. Use of the algorithm would reduce the number of OGTTs performed in the UK validation cohort by 33% and by 66% in the Australian patients studied. Conclusions, Use of this algorithm would simplify procedures for diagnosis of diabetes and could also be used for monitoring pre-diabetes. Validation is now required in other populations and patient groups. [source]

    Validation of the Mayo Dysphagia Questionnaire

    DISEASES OF THE ESOPHAGUS, Issue 3 2007
    A. B. M. Grudell
    SUMMARY., While multiple instruments characterize upper gastrointestinal symptoms, a validated instrument devoted to the measurement of a spectrum of esophageal dysphagia attributes is not available. Therefore, we constructed and validated the Mayo Dysphagia Questionnaire (MDQ). The 27 items of the MDQ underwent content validity, feasibility, concurrent validity, reproducibility, internal consistency, and construct validity testing. To assess content validity, five esophageal subspecialty gastroenterologists reviewed the items to ensure inclusion of pertinent domains. Feasibility testing was done with eight outpatients who refined problematic items. To assess concurrent validity, 70 patient responses on the MDQ were compared to responses gathered in a structured patient-physician interview. A separate group of 70 outpatients completed the MDQ twice to assess the reproducibility of each item. A total of 148 patients participated in the validation process (78 [53%] men; mean age 62). On average, the MDQ took 6 minutes to complete. A single item (odynophagia) tested poorly with a kappa value of < 0.4. Otherwise, the majority of concurrent validity kappa values were in the good to excellent range with a mean of 0.63 (95% CI 0.22,0.89). The majority of reproducibility kappa values were also in the good to excellent range with a median kappa value of 0.76 (interquartile range: 0.67,0.81). Cronbach's alpha values were excellent in the range of 0.86,0.88. Spearman rank correlation coefficients to assess construct validity were also excellent in the range of 0.87,0.98. Thus, the MDQ is a concise instrument that demonstrates overall excellent concurrent validity, reproducibility, internal consistency, and construct validity for the features of esophageal dysphagia. [source]

    Validation of the World Health Organization Alcohol, Smoking and Substance Involvement Screening Test (ASSIST): report of results from the Australian site

    DRUG AND ALCOHOL REVIEW, Issue 3 2005
    DAVID A. L. NEWCOMBE
    Abstract The concurrent, construct, discriminative and predictive validity of the World Health Organization's Alcohol Substance Involvement Screening Test (ASSIST) were examined in an Australian sample. One hundred and fifty participants, recruited from drug treatment (n = 50) and primary health care (PHC) settings (n = 100), were administered a battery of instruments at baseline and a modified battery at 3 months. Measures included the ASSIST; the Addiction Severity Index-Lite (ASI-Lite); the Severity of Dependence Scale (SDS); the MINI International Neuropsychiatric Interview (MINI-Plus); the Rating of Injection Site Condition (RISC); the Drug Abuse Screening Test (DAST); the Alcohol Use Disorders Identification Test (AUDIT); the Revised Fagerstrom Tolerance Questionnaire (RTQ); and the Maudsely Addiction Profile (MAP). Concurrent validity was demonstrated by significant correlations between ASSIST scores and scores from the ASI-lite, SDS, AUDIT and DAST; and significantly greater ASSIST scores for those with diagnoses of abuse or dependence. Construct validity was established by significant correlations between ASSIST scores and measures of risk factors for the development of drug and alcohol problems. Participants diagnosed with attention deficit/hyperactivity disorder or antisocial personality disorder had significantly higher ASSIST scores than those not diagnosed as such. Discriminative validity was established by the capacity of the ASSIST to discriminate between substance use, abuse and dependence. ROC analysis was able to establish cut-off scores for an Australian sample, with suitable specificities and sensitivities for most substances. Predictive validity was demonstrated by similarity in ASSIST scores obtained at baseline and at follow-up. The findings demonstrated that the ASSIST is a valid screening test for psychoactive substance use in individuals who use a number of substances and have varying degrees of substance use. [source]

    Contractile Reserve Assessed Using Dobutamine Echocardiography Predicts Left Ventricular Reverse Remodeling after Cardiac Resynchronization Therapy: Prospective Validation in Patients with Left Ventricular Dyssynchrony

    ECHOCARDIOGRAPHY, Issue 6 2010
    F.R.C.P.C., Mario Sénéchal M.D.
    Background: The presence of viable myocardium may predict response to cardiac resynchronization therapy (CRT). The aim of this study is to evaluate in patients with left ventricular (LV) dyssynchrony whether response to CRT is related to myocardial viability in the region of the pacing lead. Methods: Forty-nine consecutive patients with advanced heart failure, LV ejection fraction < 35%, QRS duration > 120 ms and intraventricular asynchronism , 50 ms were included. Dobutamine stress echocardiography was performed within the week before CRT implantation. Resting echocardiography was performed 6 months after CRT implantation. Viability in the region of LV pacing lead was defined as the presence of viability in two contiguous segments. Response to CRT was defined by evidence of reverse LV remodeling (,15% reduction in LV end-systolic volume). Results: Thirty-one patients (63%) were identified as responders at follow-up. The average of viable segments was 5.9 ± 2 in responders and 3.2 ± 3 in nonresponders (P = 0.0003). Viability in the region of the pacing lead had a sensitivity of 94%, a specificity of 67%, a positive predictive value of 83%, and a negative predictive value of 86% for the prediction of response to CRT. Conclusions: In patients with LV dyssynchrony, reverse remodeling after CRT requires viability in the region of the pacing lead. This simple method using echocardiography dobutamine for the evaluation of local viability (i.e., viability in two contiguous segments) may be useful to the clinician in choosing the best LV lead positioning. (Echocardiography 2010;27:668-676) [source]

    Validation of the Peak to Mean Pressure Decrease Ratio as a New Method of Assessing Aortic Stenosis Using the Gorlin Formula and the Cardiovascular Magnetic Resonance-Based Hybrid Method

    ECHOCARDIOGRAPHY, Issue 4 2007
    Dariusch Haghi M.D.
    Background: We sought to validate the recently introduced peak to mean pressure decrease ratio (PMPDR), using the Gorlin formula and a hybrid method which combines cardiovascular magnetic resonance (CMR)-derived stroke volume with transaortic Doppler measurements to calculate aortic valve area (AVA). Methods: Data analysis in 32 patients with severe (AVA <= 0.75 cm2) or moderate aortic stenosis who had prospectively been entered into our aortic stenosis database. Results: Gorlin-derived AVA was 0.61 ± 0.10 cm2 in severe and 0.92 ± 0.14 cm2 in moderate aortic stenosis (P < 0.01). Corresponding values for PMPRD were 1.61 ± 0.10 and 1.73 ± 0.18, respectively (P < 0.05). Sensitivity, specificity, positive and negative predictive values for PMPDR <1.5 to predict severe aortic stenosis were 0.12, 0.92, 0.67, and 0.44 as assessed by the Gorlin formula. Conclusions: Using the Gorlin formula as the reference standard, our study confirms results of a previously reported study on the performance of PMPDR for assessment of aortic stenosis. [source]

    In Vitro Validation of a New Approach for Quantitating Regurgitations Using Proximal Isovelocity Surface Area

    ECHOCARDIOGRAPHY, Issue 7 2000
    A. Delouche
    The present work has been designed to validate the calculation of the effective regurgitant orifice (ERO) area with the use of a new formula that takes into account the velocity profile (Vr vs r) and that is insensitive to errors in the determination of the position of the orifice. Assuming a hemispheric model, ERO = 2,r2· Vr/Vo (with Vo= velocity at the orifice) and (Vo/Vr)0.5= (2,/ERO)0.5r. Thus, the slope of the corresponding linear regression allows ERO to be calculated as: ERO = 2,/slope2. This approach was tested in vitro in pulsatile conditions on circular, conical, and slit-like orifices. The calculated ERO was compared with the actual jet cross sectional area derived from the transverse velocity profile at the jet origin. For the purpose of comparison, the "classical" ERO was calculated for all the configurations, angulations, and threshold velocities. The relationship between (Vo/Vr)0.5 was linear (r > 0.98) over a wide range of velocities. The nonhemispheric components were found to modify the constant and not the slope. The mean variation of the calculated ERO was 6.5%. The correlation between the calculated and the actual ERO was very close (>0.97) with slope equal to 0.96. By comparison with the new method, the classical formula gave an underestimation of the ERO that dramatically increased when studying the flow closer to the orifice or in the case of error on the measurement of r. In conclusion, a method using velocity profiles instead of isolated values improves the accuracy of the proximal isovelocity surface area (PISA) method for measuring the ERO. [source]

    Role of Transthoracic Echocardiography in Atrial Fibrillation

    ECHOCARDIOGRAPHY, Issue 4 2000
    RICHARD W. ASINGER M.D.
    Atrial fibrillation is a major clinical problem that is predicted to be encountered more frequently as the population ages. The clinical management of atrial fibrillation has become increasingly complex as new therapies and strategies have become available for ventricular rate control, conversion to sinus rhythm, maintenance of sinus rhythm, and prevention of thromboembolism. Clinical and transthoracic echocardiographic features are important in determining etiology and directing therapy for atrial fibrillation. Left atrial size, left ventricular wall thickness, and left ventricular function have independent predictive value for determining the risk of developing atrial fibrillation. Left atrial size may have predictive value in determining the success of cardioversion and maintaining sinus rhythm in selected clinical settings but has less value in the most frequently encountered group, patients with nonvalvular atrial fibrillation, in whom the duration of atrial fibrillation is the most important feature. When selecting pharmacological agents to control ventricular rate, convert to sinus rhythm, and maintain normal sinus rhythm, transthoracic echocardiography (TTE) allows noninvasive evaluation of left ventricular function and hence guides management. The combination of clinical and transthoracic echocardiographic features also allows risk stratification for thromboembolism and hemorrhagic complications in atrial fibrillation. High-risk clinical features for thromboembolism supported by epidemiological observations, results of randomized clinical trials, and meta-analyses include rheumatic valvular heart disease, prior thromboembolism, congestive heart failure, hypertension, older (> 75 years old) women, and diabetes. Small series of cases also suggest those with hyperthyroidism and hypertrophic cardiomyopathy are at high risk. TTE plays a unique role in confirming or discovering high-risk features such as rheumatic valvular disease, hypertrophic cardiomyopathy, and decreased left ventricular function. Validation of the risk stratification scheme used in the Stroke Prevention in Atrial Fibrillation-III trial is welcomed by clinicians who are faced daily with balancing the benefit and risks of anticoagulation to prevent thromboembolism inpatients with atrial fibrillation. [source]

    Validation of daily increment formation and the effects of different temperatures and feeding regimes on short-term otolith growth in Australian smelt Retropinna semoni

    ECOLOGY OF FRESHWATER FISH, Issue 2 2008
    Z. Tonkin
    Abstract,,, To aid otolith interpretation of wild fish, we conducted a laboratory study using metalarval Australian smelt (Retropinna semoni) collected from the Murray River, to examine daily increment deposition and the effects of different temperatures and feeding regimes on otolith growth. Daily increment deposition was confirmed by comparing the number of increments from an oxytetracycline mark with the known number of days from marking. After holding fish at two temperature levels and three feeding rates, both food density and temperature were found to have a significant effect on otolith growth, with food density having the greatest influence. Overall trends in final lengths and condition of fish were well represented by recent otolith growth. The results of the experiment have implications for estimating growth histories and its relationship to various environmental conditions. [source]

    Stakeholders in Comprehensive Validation of Standards-Based Assessments: A Commentary

    EDUCATIONAL MEASUREMENT: ISSUES AND PRACTICE, Issue 1 2002
    Linda Crocker
    Linda Cracker is a Professor of Educational Psychology, University ofFlorida, P.O. Box 11 7047 Gainesville, FL 32611-7043. Her areas of specialization are assessment development, validation, and test-taking behavior. [source]

    Assessment Validation in the Context of High-Stakes Assessment

    EDUCATIONAL MEASUREMENT: ISSUES AND PRACTICE, Issue 1 2002
    Katherine Ryan
    Including the perspectives of stakeholder groups (e.g., teachers, parents) can improve the validity of high-stakes assessment interpretations and uses. How stakeholder groups view high-stakes assessments and their uses may differ significantly from state-level policy officials. The views of these stakeholders can contribute to identifying the strengths and weaknesses of the intended assessment interpretations and uses. This article proposes a process approach to validity that addresses assessment validation in the context of high-stakes assessment. The process approach includes a test evaluator or validator who considers the perspectives of five stakeholder groups at four different stages of assessment maturity in relationship to six aspects of construct validity. The tasks of the test evaluator and how stakeholders' views might be incorporated are illustrated at each stage of assessment maturity. How the test evaluator might make judgments about the merit of high-stakes assessment interpretations and uses is discussed. [source]

    Flow-Through Assay of Quinine Using Solid Contact Potentiometric Sensors Based on Molecularly Imprinted Polymers

    ELECTROANALYSIS, Issue 24 2009
    Ayman
    Abstract Miniaturized potentiometric membrane sensors for quinine incorporated with molecular imprinted polymer (MIP) were synthesized and implemented. Planar PVC based polymeric membrane sensors containing quinine-methacrylic and/or acrylic acid-ethylene glycol methacrylate were dispensed into anisotropically etched wells on polyimide wafers. The determination of quinine was carried out in acidic solution at pH,6, where positively charged species predominated prevalently. The suggested miniaturized planner sensors exhibited marked selectivity, sensitivity, long-term stability and reproducibility. At their optimum conditions, the sensors displayed wide concentration ranges of 4.0×10,6,1.0×10,2mol L,1 and 1.0×10,5,1.0×10,2 mol L,1 with slopes of about 61.3,55.7,mV decade,1; respectively. Sensors exhibit detection limits of 1.2×10,6 and 8.2×10,6 mol L,1 upon the use of methacrylic and acrylic acid monomers in the imprinted polymer, respectively. Validation of the assay method according to the quality assurance standards (range, within-day repeatability, between-day variability, standard deviation, accuracy, and good performance characteristics) which could assure good reliable novel sensors for quinine estimation was justified. Application of the proposed flow-through assay method for routine determination of quinine in soft drinks was assayed and the results compared favorably with data obtained by the standard fluorimetric method. [source]

    Novel Thorium Membrane Sensors with Anionic Response Based on Trioctylphosphine Oxide and Toluate Ionophores

    ELECTROANALYSIS, Issue 19 2008

    Abstract Two novel potentiometric polymeric membrane sensors for rapid and accurate determination of thorium are described. These are based on the use of trioctylphosphine oxide (TOPO) and thorium toluate (Th-TA) as ionophores dispersed in poly(vinyl chloride) matrix membranes plasticized with nitrophenyloctyl ether. In strong nitric acid medium, Th(IV) nitrate is converted into [Th(NO3)6]2, complex and sensed as anionic divalent ion which exclude most cationic effect. Validation of the assay methods using the quality assurance standards (linearity range, accuracy, precision, within-day variability, between-day-repeatability, lower detection limit and sensitivity) reveals excellent performance characteristics of both sensors. The sensors exhibit near-Nernstian response for 1.0×10,6,1.0×10,1 M Th over the pH range 2.5,4.5. Calibration slopes of ,32.3±0.3 and ,27.2±0.2,mV/decade, precision of ±0.5 and ±0.8% and accuracy of 98.8±0.9 and 97.9±0.7% are obtained with TOPO and Th-TA based sensors, respectively. Negligible interferences are caused by most interfering mono-, di-, tri-, tetra-, penta-, and hexa-valent elements commonly associated with thorium in naturally occurring minerals and ores. High concentrations of Cl,, F,, SO42,, and NO3, ions have no diverse effect. Complete removal of the effect of the interferents in complex matrices is achieved by retention of [Th(NO3)6]2, complex from 5,M nitric acid/methanol mixture (1,:,9,v/v) on a strong anion exchanger, washing out the cationic interferents followed by stripping off thorium anion complex and measurements. Both sensors are used for determining thorium in certified thorium ore samples (20,120,mg Th/kg) and some naturally occurring ores (200,600,mg Th/kg). The results obtained agree fairly well with the certified labeled values or the data obtained using X-ray fluorescence spectrometry [source]

    Lead(II) Potentiometric Sensor Based on 1,4,8,11-Tetrathiacyclotetradecane Neutral Carrier and Lipophilic Additives

    ELECTROANALYSIS, Issue 11 2008
    Mohamed
    Abstract A potentiometric sensor for lead(II) ions based on the use of 1,4,8,11-tetrathiacyclotetradecane (TTCTD) as a neutral ionophore and potassium tetrakis-(p -chlorophenyl)borate as a lipophilic additive in plasticized PVC membranes is developed. The sensor exhibits linear potentiometric response towards lead(II) ions over the concentration range of 1.0×10,5,1.0×10,2,mol L,1 with a Nernstian slope of 29.9,mV decade,1 and a lower limit of detection of 2.2×10,6,mol L,1 Pb(II) ions over the pH range of 3,6.5. Sensor membrane without a lipophilic additive displays poor response. The sensor shows high selectivity for Pb(II) over a wide variety of alkali, alkaline earth and transition metal ions. The sensor shows long life span, high reproducibility, fast response and long term stability. Validation of the method by measuring the lower limit of detection, lower limit of linear range, accuracy, precision and sensitivity reveals good performance characteristics of the proposed sensor. The developed sensor is successfully applied to direct determination of lead(II) in real samples. The sensor is also used as an indicator electrode for the potentiometric titration of Pb(II) with EDTA and potassium chromate. The results obtained agree fairly well with data obtained by AAS. [source]

    Quantification of SMN1 and SMN2 genes by capillary electrophoresis for diagnosis of spinal muscular atrophy

    ELECTROPHORESIS, Issue 13 2008
    Chun-Chi Wang
    Abstract We present the first CE method for the separation and quantification of SMN1 and SMN2 genes. Spinal muscular atrophy (SMA) is an inherited neuromuscular disorder deleted or mutated in SMN1 gene and retained at least one copy of SMN2 gene. However, these two genes are highly homologous, differentiation and quantification of SMN1 and SMN2 are therefore required in diagnosis to identify SMA patients and carriers. We developed a fluorescence-labeled conformation-sensitive CE method to quantitatively analyze PCR products covering the variable position in the SMN1/SMN2 genes using a copolymer solution composed of hydroxyethylcellulose and hydroxypropylcellulose. The DNA samples included 24 SMA patients, 52 parents of SMA patients (obligatory carriers), and 255 controls. Those 331 samples were blind analyzed to evaluate the method, and the results compared with those obtained using denaturing HPLC (DHPLC). Validation of accuracy was performed by comparing the results with those of DHPLC. Nine of total samples showed different results. Diagnosis of one fetus DNA among them was related to abortion or not, which was further confirmed by gel electrophoresis and DNA sequencing. Our method showed good coincidence with them, and proved the misdiagnosis of DHPLC. This simple and reliable CE method is a powerful tool for clinical genotyping of large populations to detect carriers and SMA patients. [source]

    Analysis of flavonoids by CE using capacitively coupled contactless conductivity detection

    ELECTROPHORESIS, Issue 5 2007
    Stefan Bachmann
    Abstract A CE method employing capacitively coupled contactless conductivity (C4D) compared to indirect UV-detection was developed for the analysis of phytochemically relevant flavonoids, such as 6-hydroxyflavone, biochanin A, hesperetin and naringenin. To ensure fast separation at highest selectivity, sensitivity and peak symmetry, the pH value and the concentration of the running BGE had to be optimized regarding both co- and counter-EOF mode. Optimum conditions were found to be 1.0 and 5.0,mM chromate BGE (pH,9.50) in the counter- and co-EOF mode, respectively. Validation of the established CE-C4D method pointed out to be approximately seven times more sensitive compared to indirect UV-detection applying the same conditions. The lower LOD defined at an S/N of 3:1 was found between 0.12 and 0.21,µg/mL for the analytes of interest using C4D and between 0.77 and 1.20,µg/mL using indirect UV-detection. Compared to an earlier published CE method employing direct UV-detection, C4D was found to be approximately two times more sensitive. Due to the lower baseline noise, C4D showed an excellent regression coefficient >0.99 compared to 0.93 when using indirect UV detection calibrating within a concentration range between 1 and 10,µg/mL. The influence of the sugar moiety on the conductivity of a flavonoid was studied upon the analysis of the aglycon hesperetin and the rutinosid hesperidin. The sugar moiety in hesperedin shows a higher conductivity compared to hesperetin. Finally, the optimized established CE-C4D method was applied to the determination and quantification of naringenin in Sinupret®. [source]

    Validation of emergency physician ultrasound in diagnosing hydronephrosis in ureteric colic

    EMERGENCY MEDICINE AUSTRALASIA, Issue 3 2007
    Stuart Watkins
    Abstract Objective:, Patients presenting to the ED with obstructive nephropathies benefit from early detection of hydronephrosis. Out of hours radiological imaging is expensive and disruptive to arrange. Emergency physician ultrasound (EPU) could allow rapid diagnosis and disposition. If accurate it might avert the need for formal radiological imaging, exclude an obstruction and improve patient flow through the ED. Methods:, This was a prospective study of a convenience sample of all adult non-pregnant patients with presumed ureteric colic attending the ED with prior ethics committee approval. An emergency physician or registrar performed a focused ultrasound scan and were blinded to the patient's other management. A computerized tomography scan was also performed for all patients while in the ED or within 24 h of the EPU. The accuracy of EPU detection of hydronephrosis was determined; using computerized tomography scans reported by a senior radiologist as the ,gold-standard'. Results:, Sixty-three patients with suspected ureteric colic were enrolled of whom 57 completed both EPU and computerized tomography imaging. Forty-nine had confirmed nephrolithiasis by computerized tomography with 39 having evidence of hydronephrosis. Overall prevalence of hydronephrosis was 68% (95% confidence interval [CI] 56,79%); compared with computerized tomography, EPU had a sensitivity of 80% (95% CI 65,89%); specificity of 83% (95% CI 61,94%); positive predictive value of 91% (95% CI 75,98%) and negative predictive value of 65% (95% CI 43,83%). The overall accuracy was 81% (95% CI 69,89%). Conclusion:, Although the accuracy of detection of hydronephrosis after focused training in EPU is encouraging, further experience and training might improve the accuracy of EPU and allow its use as a screening tool. [source]

    Validation of a tool to safely triage selected patients with chest pain to unmonitored beds

    EMERGENCY MEDICINE AUSTRALASIA, Issue 4 2002
    Ronald V Sultana
    Abstract Objective: To externally validate a chest pain protocol that triages low risk patients with chest pain to an unmonitored bed. Methods: Retrospective study of all patients admitted from the emergency department of a tertiary referral public teaching hospital with an admission diagnosis of ,unstable angina' or suspected ischemic chest pain. Data was collected on adverse outcomes and analysed on the basis of intention-to-treat according to the chest pain protocol. Results: There were no life-threatening arrhythmias, cardiac arrests or deaths within the first 72 h of admission in the group assigned to an unmonitored bed by the chest pain protocol ([0/244]; 0.0%: 95% confidence interval 0.0,1.5%). Four patients had an uncomplicated myocardial infarction, two patients had recurrent ischemic chest pain and one patient developed acute pulmonary oedema ([7/244]; 2.9%: 95% confidence interval 1.2,5.8%). Conclusion: This retrospective study externally validated the chest pain protocol. Care in a monitored bed would not have altered outcomes for patients triaged to an unmonitored bed by the chest pain protocol. Compared to current guidelines, application of the chest pain protocol could increase the availability of monitored beds. [source]

    Validation of the alcohol, smoking and substance involvement screening test (ASSIST)

    ADDICTION, Issue 6 2008
    Rachel Humeniuk
    ABSTRACT Aim The concurrent, construct and discriminative validity of the World Health Organization's Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) were examined in a multi-site international study. Participants One thousand and 47 participants, recruited from drug treatment (n = 350) and primary health care (PHC) settings (n = 697), were administered a battery of instruments. Measurements Measures included the ASSIST; the Addiction Severity Index-Lite (ASI-Lite); the Severity of Dependence Scale (SDS); the MINI International Neuropsychiatric Interview (MINI-Plus); the Rating of Injection Site Condition (RISC); the Drug Abuse Screening Test (DAST); the Alcohol Use Disorders Identification Test (AUDIT); the Revised Fagerstrom Tolerance Questionnaire (RTQ); and the Maudsley Addiction Profile (MAP). Findings Concurrent validity was demonstrated by significant correlations between ASSIST scores and scores from the ASI-Lite (r = 0.76,0.88), SDS (r = 0.59), AUDIT (r = 0.82) and RTQ (r = 0.78); and significantly greater ASSIST scores for those with MINI-Plus diagnoses of abuse or dependence (P < 0.001). Construct validity was established by significant correlations between ASSIST scores and measures of risk factors for the development of drug and alcohol problems (r = 0.48,0.76). Discriminative validity was established by the capacity of the ASSIST to discriminate between substance use, abuse and dependence. Receiver operating characteristic (ROC) analysis was used to establish cut-off scores with suitable specificities (50,96%) and sensitivities (54,97%) for most substances. Conclusions The findings demonstrated that the ASSIST is a valid screening test for identifying psychoactive substance use in individuals who use a number of substances and have varying degrees of substance use. [source]

    Validation of a modified Flory-Huggins concept for description of hydrophobic organic compound sorption on dissolved humic substances

    ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2002
    Anett Georgi
    Abstract Sorption coefficients(KDOC) on dissolved organic matter (DOM) have been determined by means of solid-phase microextraction (SPME) for hydrophobic organic compounds (HOCs) of various classes, for example, polycyclic aromatic hydrocarbons (PAHs), noncondensed arenes, and alkanes. Relating the KDOC values obtained to the octanol-water partition coefficients of the solutes results in class-specific correlations. Obviously, PAHs have a higher affinity to DOM than other HOCs with equal KOW values. The different KDOC to KOW correlations can be combined into one general formula based on a modified Flory-Huggins concept. It permits the calculation of sorption coefficients from the solubility parameters (,) and KOW values of the solutes and the solubility parameter of the sorbent. The latter value, which is specific to the DOM under consideration, can be determined from a single measured sorption coefficient. By applying the proposed Flory-Huggins concept, which is based on the presumption of nonspecific interactions between HOCs and DOM, the different affinities of PAHs, noncondensed arenes, and alkanes to DOM can be accurately predicted. [source]

    Biomimetic solid-phase microextraction to predict body residues and toxicity of chemicals that act by narcosis

    ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2002
    Heather A. Leslie
    Abstract A biomimetic extraction technique using solid-phase microextraction (SPME) fibers has been developed for the risk assessment of contaminants with a narcotic mode of action. Our goal is to apply this technique in the future for the prediction of total baseline toxicity of environmental water and effluent samples. Validation of this method requires establishing the relationship between contaminant accumulation and toxicity in biota and accumulation in the surrogate solid phase (the SPME fiber coating). For this purpose, we determined the median lethal concentration (LC50) values for Chironomus riparius midge larvae exposed to two halogenated aromatic compounds separately and measured body residues in the exposed larvae. Solid-phase microextraction fibers with an 85-,m polyacrylate (PA) coating served as the surrogate hydrophobic phase, mimicking the uptake of the compounds by midge larvae. The toxicant concentrations in SPME fibers measured directly by gas chromatography/mass spectrometry (GCMS) or calculated from the SPME fiber,water partition coefficient, KSPME, were related to the toxicant concentrations found in midge larvae. Our results demonstrated that the biomimetic SPME method enables the estimation of body residues in biota and prediction of the degree of baseline toxicity of a water medium. [source]