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Better Discrimination (good + discrimination)
Selected AbstractsDiscrimination of G-Quadruplexes from Duplex and Single-Stranded DNAs with Fluorescence and Energy-Transfer Fluorescence Spectra of Crystal VioletCHEMISTRY - A EUROPEAN JOURNAL, Issue 4 2009De-Ming Kong Dr. Abstract G-rich nucleic acid sequences with the potential to form G-quadruplex structures are common in biologically important regions. Most of these sequences are present with their complementary strands, so the development of a sensitive biosensor to distinguish G-quadruplex and duplex structures and to determine the competitive ability of quadruplex to duplex structures has received a great deal of attention. In this work, the interactions between two triphenylmethane dyes (malachite green (MG) and crystal violet (CV)) and G-quadruplex, duplex, or single-stranded DNAs were studied by fluorescence spectroscopy and energy-transfer fluorescence spectroscopy. Good discrimination between quadruplexes and duplex or single-stranded DNAs can be achieved by using the fluorescence spectrum of CV or the energy-transfer fluorescence spectra of CV and MG. In addition, by using energy-transfer fluorescence titrations of CV with G-quadruplexes, the binding-stoichiometry ratios of CV to G-quadruplexes can be determined. By using the fluorescence titrations of G-quadruplex,CV complexes with C-rich complementary strands, the fraction of G-rich oligonucleotide that engages in G-quadruplex structures in the presence of the complementary sequence can be measured. This study may provide a simple method for discrimination between quadruplexes and duplex or single-stranded DNAs and for measuring G-quadruplex percentages in the presence of the complementary C-rich sequences. [source] The effects of dispersal mode on the spatial distribution patterns of intertidal molluscsJOURNAL OF ANIMAL ECOLOGY, Issue 4 2001M. P. Johnson Summary 1As many species of marine benthic invertebrates have a limited capacity for movement as adults, dispersal mode is often considered as a determinant of geographical ranges, genetic structure and evolutionary history. Species that reproduce without a larval stage can only disperse by floating or rafting. It is proposed that the colonization processes associated with such direct developing species result in spatial distributions that show relatively greater fine scale patchiness than the distributions of species with a larval dispersal stage. This hypothesis was tested by collecting molluscs at different spatial scales in the Isle of Man. 2Spatial distribution patterns supported the predictions based on dispersal mode. Estimated variance components for species with larval dispersal suggested that the majority of the spatial variation was associated with variation between shores. In comparison, there was relatively more variability within shores for abundance counts of species with direct development. 3Multivariate analyses reflected the univariate results. An assemblage of direct developers provided a better discrimination between sites (100 m separation) but the group of species with larval dispersal gave a clearer separation of shores (separated by several km). 4The fine scale spatial structure of direct developing species was reflected in higher average species diversity within quadrats. Species richness also reflected dispersal mode, with a higher fraction of the regional species pool present for direct developers in comparison to species with larval dispersal. This may reflect the improved local persistence of taxa that avoid the larval dispersal stage. [source] Discrimination of Staphylococcus aureus biotypes by pulsed-field gel electrophoresis of DNA macro-restriction fragmentsJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2003J.A. Hennekinne Abstract Aims: To examine whether pulsed-field gel electrophoresis (PFGE) of DNA macro-restriction fragments could provide better discrimination among the different biotypes previously described within the species Staphylococcus aureus than the traditional biochemical approach. Methods and Results: Seventy three Staph. aureus strains from various sources (human, animal or food origin) and belonging to eight biotypes, including the poultry-like biotype, tentatively designated as an ,abattoir' biotype, were genotyped by PFGE after SmaI digestion of DNA. The PFGE patterns were compared using the average linkage matching method (UPGMA) with the Dice coefficient. A total of 61 PFGE patterns were observed, showing between 31 and 100% similarity. In most cases, strains with the same biotype were grouped specifically into one, two or three separate sub-clusters. Strains from the ,abattoir' biotype were clustered in one separate sub-cluster. Conclusions: The PFGE typing is useful to distinguish the traditional biotypes of Staph. aureus and has a more discriminatory power than the biochemical typing. Significance and Impact of the Study: The PFGE typing confirms the ,abattoir' biotype as a separate group on a genetic level and is well suited to investigate modes of staphylococcal contamination of food. [source] Prognostic models in cirrhotics admitted to intensive care units better predict outcome when assessed at 48 h after admissionJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 8pt1 2008Evangelos Cholongitas Abstract Background and Aim:, The accuracy of prognostic models in critically ill cirrhotics at admission to intensive care units (ICU) may be unreliable. Predictive accuracy could be improved by evaluating changes over time, but this has not been published. The aim of the present study was to assess the performance of prognostic models in cirrhotics at admission (baseline) and at 48 h to predict mortality in the ICU or within 6 weeks after discharge from the ICU. Methods:, One hundred and twenty-eight cirrhotics (77 males, mean age 49 ± 11.3 years) were consecutively admitted and alive 48 h after admission with 89% on mechanical ventilation, 76% on inotrope support, and 42% with renal failure. Prognostic models used were Child-Turcotte-Pugh (CTP), Model for End-stage Liver Disease (MELD), Acute Physiology and Chronic Health Evaluation (APACHE) II, Sequential Organ Failure Assessment (SOFA), failing organ systems (FOS) at baseline and at 48 h, ,score (difference between baseline and at 48 h) and the mean score (MN , score admission + 48 h/2) which were compared by area under the receiver operating characteristic curves (AUC). Results:, Mortality was 54.7% (n = 70) due to multiple organ failure in 55%. CTP, MELD, APACHE II, SOFA and FOS performed better at 48 h (AUC: 0.78, 0.86, 0.78, 0.88 and 0.85, respectively) than at baseline (AUC: 0.75, 0.78, 0.75, 0.81 and 0.79, respectively). The mean score had better discrimination than the baseline score; the ,score had poor predictive ability (AUC < 0.70). SOFA score (48 h: 0.88, mean: 0.88) and FOS (mean: 0.88) had the best accuracy, with a SOFA and MN-SOFA , 10 predicting mortality in 93% and 91%, respectively, and MN-FOS , 1.5 in 98%. Conclusions:, In cirrhotics, prognostic scores in the ICU at 48 h had better discrimination than baseline scores for short-term mortality. SOFA and FOS models had the best performance. [source] A COMPARISON OF THE DISCRIMINATING POWER OF ANOVA AND R-INDEX ANALYSES OF HEDONIC DATA FOR VARIOUS PRODUCTS AND EXPERIMENTAL PROTOCOLSJOURNAL OF SENSORY STUDIES, Issue 3 2007HAENA PARK ABSTRACT Consumers rated a set of toothpastes and a set of orange-flavored beverages on a 9-point hedonic scale, using two experimental protocols: Rank-Rating where stimuli could continually be reassessed and a more traditional approach where they could not. A 21-point hedonic scale was also used in the Rank-Rating condition. The hedonic data were analyzed in the usual way using ANOVA with multiple comparisons and also by ranking the data and using an R-index analysis. Regarding the numbers of significant differences recorded, the two analyses were comparable, with a very slight and nonsignificant advantage for the ANOVA analysis. Unlike with intensity scaling, the difference between Rank-Rating and "traditional" scaling was slight but not for all products. The same was true for scale length effects. Differences among the products suggested effects due to the number of attributes that varied. PRACTICAL APPLICATIONS The key finding in this study is the use of Rank-Rating where stimuli could continually be re-assessed for the assessment of hedonic response of consumers in the various products. Rank-Rating may possibly give a better discrimination than more traditional scaling, depending on the number of attributes which varied. The results of the study also recommend the use of R-index analyses of ranked hedonic data in the analyses rather than ANOVA with multiple comparisons. [source] Precipitation analysis using the Advanced Microwave Sounding Unit in support of nowcasting applicationsMETEOROLOGICAL APPLICATIONS, Issue 2 2002Ralf Bennartz We describe a method to remotely sense precipitation and classify its intensity over water, coasts and land surfaces. This method is intended to be used in an operational nowcasting environment. It is based on data obtained from the Advanced Microwave Sounding Unit (AMSU) onboard NOAA-15. Each observation is assigned a probability of belonging to four classes: precipitation-free, risk of precipitation, precipitation between 0.5 and 5 mm/h, and precipitation higher than 5 mm/h. Since the method is designed to work over different surface types, it relies mainly on the scattering signal of precipitation-sized ice particles received at high frequencies. For the calibration and validation of the method we use an eight-month dataset of combined weather radar and AMSU data obtained over the Baltic area. We compare results for the AMSU-B channels at 89 GHz and 150 GHz and find that the high frequency channel at 150 GHz allows for a much better discrimination of different types of precipitation than the 89 GHz channel. While precipitation-free areas, as well as heavily precipitating areas (>5 mm/h), can be identified to high accuracy, the intermediate classes are more ambiguous. This stems from the ambiguity of the passive microwave observations as well as from the non-perfect matching of the different data sources and sub-optimal radar adjustment. In addition to a statistical assessment of the method's accuracy, we present case studies to demonstrate its capabilities to classify different types of precipitation and to work over highly structured, inhomogeneous surfaces. Copyright © 2002 Royal Meteorological Society [source] Chiral discrimination of , -amino acids by DNA tetranucleotides under electrospray ionization conditionsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 2 2008T. Sivaleela A set of DNA tetranucleotides, which are 3,- or 5,-end extended versions of GCA, was used as chiral selectors for the discrimination of enantiomers of , -amino acids. The [X+Y,2H]2, ions of the 1:1 complexes were generated by electrospraying a mixture of tetranucleotide (X) and amino acid (Y) solution. Chiral discrimination was achieved by studying the collision-induced dissociation spectra of the [X+Y,2H]2, ion and the ratio of relative abundance of precursor ion to that of the product ion was used to measure the extent of discrimination. Among the tetranucleotides used, GCAA and GGCA exhibited better discrimination, in which GCAA showed D-selectivity and GGCA showed L-selectivity for the studied amino acids. In addition, binding constants were measured for the 1:1 complexes of phenylalanine enantiomers with GCAA and GGCA. Copyright © 2007 John Wiley & Sons, Ltd. [source] Model-based prediction of defective DNA mismatch repair using clinicopathological variables in sporadic colon cancer patientsCANCER, Issue 7 2010Frank Sinicrope MD Abstract BACKGROUND: Colon cancers with defective DNA mismatch repair (MMR) have a favorable prognosis and may lack benefit from 5-fluorouracil,based adjuvant chemotherapy. The authors developed models to predict MMR deficiency in sporadic colon cancer patients using routine clinical and pathological data. METHODS: TNM stage II and III colon carcinomas (n = 982) from 6 5-fluorouracil,based adjuvant therapy trials were analyzed for microsatellite instability and/or MMR protein expression. Tumor-infiltrating lymphocytes (TILs) were quantified (n = 326). Logistic regression and a recursive partitioning and amalgamation analysis were used to identify predictive factors for MMR status. RESULTS: Defective MMR was detected in 147 (15%) cancers. Tumor site and histologic grade were the most important predictors of MMR status. Distal tumors had a low likelihood of defective MMR (3%; 13 of 468); proximal tumors had a greater likelihood (26%; 130 of 506). By using tumor site, grade, and sex, the logistic regression model showed excellent discrimination (c statistic = 0.81). Proximal site, female sex, and poor differentiation showed a positive predictive value (PPV) of 51% for defective MMR. In a patient subset (n = 326), a model including proximal site, TILs (>2/high-power field), and female sex showed even better discrimination (c statistic = 0.86), with a PPV of 81%. CONCLUSIONS: Defective MMR is rare in distal, sporadic colon cancers, which should generally not undergo MMR testing. Proximal site, poor differentiation, and female sex detect 51% of tumors with defective MMR; substituting TILs for grade increases the PPV to 81%. These data can increase the efficiency of MMR testing to assist in clinical decisions. Cancer 2010. © 2010 American Cancer Society. [source] Changes of QT dispersion in patients with coronary artery disease dependent on different methods of stress inductionCLINICAL CARDIOLOGY, Issue 3 2000B. Hailer M.D. Abstract Background: Episodes of stress-induced myocardial ischemia in patients with coronary artery disease (CAD) may cause increases of QT dispersion (QTd). Hypothesis: Aim of this study was to analyze the effect of increasing heart rates on QTd and to compare the effect of different methods of stress induction in patients with varying degrees of CAD when estimating QTd. Methods: We studied 58 patients, 22 with prior myocardial infarction (MI), 25 without MI or wall motion disturbances at rest, and 11 patients without evidence of CAD. Prior to coronary angiography, standard 12-lead ECGs were obtained at rest as well as during dynamic exercise and pharmacologic stress using arbutamine simultaneously with echocardiography. QTd was determined at each stress level by subtracting minimal from maximal QT interval duration. Results: QTd values at rest were not consistently higher in the patients with CAD. At maximal heart rate, QTd was statistically significantly higher in patients with CAD with a better discrimination between groups for pharmacologic stress (p < 0.005 for exercise, p < 0.0001 for arbutamine). Patients after MI had higher QTd values under all conditions than did the groups without MI. As in patients with CAD, the values of this group changed more radically as a result of pharmacologic stress. Conclusion: Patients with CAD can be identified on the basis of QTd under stress. These changes were not as marked in patients with MI as their rest values were already increased. Overall, drug-induced stress produced greater differences than dynamic exercise, suggesting that the ischemic threshold might be lower in the former. [source] Ion-Selective Electrodes for Thiocyanate Based on the Dinuclear Zinc(II) Complex of a Bis- N,O -bidentate Schiff BaseELECTROANALYSIS, Issue 12 2004Philippe Bühlmann Abstract An ion selective electrode based on the dinuclear complex formed by two zinc(II) ions and two molecules of the bis- N,O -bidentate Schiff base 2,2,-[methylenebis(4,1-phenylenenitrilomethylidyne)]bisphenol exhibits thiocyanate selectivity with a good discrimination of nitrite, nitrate, and azide. The selectivities of electrode membranes with various compositions indicate that this potentiometric selectivity is based on the formation of a 1,:,1 complex between the thiocyanate anion and the dinuclear ionophore. The 2,:,1 ratio of thiocyanate ions and the dinuclear ionophore that results from higher ratios of cationic sites and ionophore worsens the selectivity, suggesting that binding of a thiocyanate to both zinc(II) centers of the dinuclear ionophore is not favorable. Interestingly, the selectivity patterns of these electrodes differ radically from that of a highly sulfate selective electrode based on a compound reported previously to be the analogous mononuclear 1,:,1 complex of zinc(II) and the same Schiff base. It is suggested that the previously reported 1,:,1 complex with zinc(II) may indeed have been a polymer of the same elemental composition. [source] Fire regimes of China: inference from statistical comparison with the United StatesGLOBAL ECOLOGY, Issue 5 2009Meg A. Krawchuk ABSTRACT Aim, Substantial overlap in the climate characteristics of the United States and China results in similar land-cover types and weather conditions, especially in the eastern half of the two countries. These parallels suggest similarities in fire regimes as well, yet relatively little is known about the historical role of fire in Chinese ecosystems. Consequently, we aimed to infer fire regime characteristics for China based on our understanding of climate,fire relationships in the United States. Location, The conterminous United States and the People's Republic of China. Methods, We used generalized additive models to quantify the relationship between reference fire regime classes adopted by the LANDFIRE initiative in the United States, and a global climate data set. With the models, we determined which climate variables best described the distribution of fire regimes in the United States then used these models to predict the spatial distribution of fire regimes in China. The fitted models were validated quantitatively using receiver operating characteristic area under the curve (AUC). We validated the predicted fire regimes in China by comparison with palaeoecological fire data and satellite-derived estimates of current fire activity. Results, Quantitative validation using the AUC indicated good discrimination of the distribution of fire regimes by models for the United States. Overall, fire regimes with more frequent return intervals were more likely in the east than in the west. The resolution of available historical and prehistorical fire data for China, including sediment cores, allowed only coarse, qualitative validation, but provided supporting evidence that fire has long been a part of ecosystem function in eastern China. MODIS satellite data illustrated that fire frequency within the last decade supported the classification of much of western China as relatively fire-free; however, much of south-eastern China experiences more fire activity than predicted with our models, probably as a function of the extensive use of fire by people. Conclusions, While acknowledging there are many cultural, environmental and historical differences between the United States and China, our fire regime models based on climate data demonstrate potential historical fire regimes for China, and propose that large areas of China share historical fire,vegetation,climate complexes with the United States. [source] Use of a novel technology for presenting screening measures to detect mild cognitive impairment in elderly patientsINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 9 2010D. W. Wright Summary Background:, Available screening tools for mild cognitive impairment (MCI), often a precursor to Alzheimer's disease, are insensitive or not feasible for administration in a busy primary care setting. Display Enhanced TEsting for Cognitive impairment and Traumatic brain injury (DETECTÔ) addresses these issues by creating an immersive environment for the brief administration of neuropsychological (NP) measures. Objective:, The aim of this study was to determine if the DETECTÔ cognitive subtests can identify MCI patients as accurately as standard pen and paper NP tests. Methods:, Twenty patients with MCI recruited from a memory disorders clinic and 20 age-matched controls were given both a full battery of NP tests (standard NP) and the DETECTÔ screen. Logistic regression models were used to determine whether individual tests were predictive of group membership (MCI or control). Demographic variables including age, race, education and gender were adjusted as covariates. Selection methods were used to identify subset models that exhibited maximum discrimination between MCI patients and controls for both testing methods. Results:, Both the standard NP model (C-index = 0.836) and the DETECTÔ model (C-index = 0.865) showed very good discrimination and were not significantly different (p = 0.7323). Conclusion:, The DETECTÔ system shows good agreement with standard NP tests and is capable of identifying elderly patients with cognitive impairment. [source] A comparison of SAPS II and SAPS 3 in a Norwegian intensive care unit populationACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2009K. STRAND Background: Simplified Acute Physiology Score (SAPS II) is the most widely used general severity scoring system in European intensive care medicine. Because its performance has been questioned in several external validation studies, SAPS 3 was recently released. To our knowledge, there are no published validation studies of SAPS II or SAPS 3 in the Scandinavian countries. We aimed to evaluate and compare the performance of SAPS II and SAPS 3 in a Norwegian intensive care unit (ICU) population. Method: Prospectively collected data from adult patients admitted to two general ICUs at two different hospitals in Norway were used. Probability of mortality was calculated using the SAPS 3 global equation (SAPS 3 G), the SAPS 3 Northern European equation (SAPS 3 NE), and the original SAPS II equation. Performance was assessed by the standardized mortality ratio (SMR), area under receiving operating characteristic, and the Hosmer and Lemeshow goodness-of-fit , test. Results: One thousand eight hundred and sixty-two patients were included after excluding readmissions, and patients who were admitted after coronary surgery or burns. The SMRs were SAPS 3 G 0.71 (0.65, 0.78), SAPS 3 NE 0.74 (0.68, 0.81), and SAPS II 0.82 (0.75, 0.91). Discrimination was good in all systems. Only the SAPS 3 equations displayed satisfactory calibration, as measured by the Hosmer,Lemeshow test. Conclusion: The performance of SAPS 3 was satisfactory, but not markedly better than SAPS II. Both systems considerably overestimated mortality and exhibited good discrimination, but only the SAPS 3 equations showed satisfactory calibration. Customization of these equations based on a larger cohort is recommended. [source] CT and Cross-sectional Anatomy of the Normal Head of the Loggerhead Sea Turtle (Caretta caretta)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005A. Arencibia The objective of this study is to describe the CT anatomy of the normal loggerhead sea turtle (Caretta caretta) head using three loggerhead sea turtle heads. CT imaging was performed using the following parameters: K.v.: 120 mAs: 220, and a soft-tissue window (WW 1880, WL 465): Transverse and sagittal CT images were obtained. Detailed anatomy of the head was acquired with the sagittal and transverse series. The heads were frozen and then sectioned using an electric saw, to compare them with the CT images. In CT, the grey scale is directly related to the radiation attenuation of the head structures. The skull and hyoid bones, and the lower jaw were easily identifiable due to the high CT density image compared to adjacent or surrounding structures such as the respiratory system, oral cavity, oesophagus and cranial cavity that appeared as a low opacity. The nervous structures, salt gland, eyeball, ramphoteca structure and different muscles of the head had an intermediate CT density and appeared grey. CT images of the loggerhead sea turtle head provided excellent detail of clinically relevant anatomy and correlated well with corresponding gross specimens. CT of the head has considerable advantages over other techniques: CT provides excellent spatial resolution and good discrimination between bone and soft tissue, and the structures are viewed without superimposition. The planimetric or sectional anatomy of the head allows a correct morphologic and topographic evaluation of the anatomic structures, which is a useful tool for the identification of the CT images. With developing technology, CT imaging may soon become more readily available for exotic animals imaging. In the same way, we consider it quite useful to be able to establish some references on head, in order to scan only selected parts during a clinical or experimental approach. The information presented in this communication should serve as an initial reference to evaluate CT images of the loggerhead sea turtle head and to assist interpretation of lesions of this region. [source] Elderly POSSUM, a dedicated score for prediction of mortality and morbidity after major colorectal surgery in older patientsBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 3 2010P. Tran Ba Loc Background: Several scores have been developed to evaluate surgical unit mortality and morbidity. The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) and derivatives use preoperative and intraoperative factors, whereas the Surgical Risk Scale (SRS) and Association Française de Chirurgie (AFC) score use four simple factors. To allow for advanced age in patients undergoing colorectal surgery, a dedicated score,the Elderly (E) POSSUM,has been developed and its accuracy compared with these scores. Methods: From 2002 to 2004, 1186 elderly patients, at least 65 years old, undergoing major colorectal surgery in France were enrolled. Accuracy was assessed by calculating the area under the receiver operating characteristic curve (AUC) (discrimination) and calibration. Results: The mortality and morbidity rates were 9 and 41 per cent respectively. The E-POSSUM had both a good discrimination (AUC = 0·86) and good calibration (P = 0·178) in predicting mortality and a reasonable discrimination (AUC = 0·77) and good calibration (P = 0·166) in predicting morbidity. The E-POSSUM was significantly better at predicting mortality and morbidity than the AFC score (Pc = 0·014 and Pc < 0·001 respectively). Conclusion: The E-POSSUM is a good tool for predicting mortality, and the only efficient scoring system for predicting morbidity after major colorectal surgery in the elderly. Copyright © 2010 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Rolling-Circle Amplification: Unshared Advantages in miRNA DetectionCHEMBIOCHEM, Issue 8 2009Saskia Neubacher Abstract Roll with it: The quantitative analysis of specific miRNAs from biological samples is very likely to revolutionize diagnostics of human disease. A novel method for miRNA analysis employing rolling-circle amplification (RCA) can homogeneously detect miRNA, even at concentrations as low as 10 fM. The use of T4 RNA ligase 2 (T4,RnL2) at elevated temperatures enables very good discrimination of miRNAs differing by a single nucleotide. [source] | ||||||||||||||||