Height Ratio (height + ratio)

Distribution by Scientific Domains

Kinds of Height Ratio

  • peak height ratio


  • Selected Abstracts


    Voltammetric Studies of Parallel Electrode Processes Under Low Ionic Strength Conditions.

    ELECTROANALYSIS, Issue 7 2006
    Influence of Convection
    Abstract It is known that either a very strong enhancement or an almost complete depression of the height of one of two waves can be obtained when two analytes (one appropriately charged and one uncharged) are present in a quiet solution containing no supporting electrolyte. In this paper we examine whether these effects can be extended for solutions with forced convection. Three two-analyte mixtures were examined voltammetrically under conditions of no added supporting electrolyte and added convection. The first mixture (1,1,-ferrocenedimethanol and ferrocenesulfonate anion) changes its total charge from ,1 to +1 after electrooxidation of both components. Under all applied conditions, the introduction of convection caused an increase of both waves without changing the wave height ratio. A similar behavior was observed for the mixture of ferrocene and 1,1,-ferrocenedimethanol. For this system the total charge changes from 0 to +2. A substantial influence of convection on the ratio of two waves was found for the third mixture: ferrocene and ferrocenylmethyltrimethylammonium cation (total charge changes from +1 to +3). For this system the convection strongly depressed the migrational effects. The obtained experimental results were verified with simulations using software MIOTRAS. This software is capable of modeling diffusion, migration, convection and following homogenous reactions. The agreement between experiment and simulations was fairly good. [source]


    Prediction of incipient pasture-associated laminitis from hyperinsulinaemia, hyperleptinaemia and generalised and localised obesity in a cohort of ponies

    EQUINE VETERINARY JOURNAL, Issue 2 2009
    R. A. CARTER
    Summary Reasons for performing study: The ability to predict ponies at increased risk of laminitic episodes, when exposed to nutrient dense pasture, would facilitate management to avoid disease. Objectives: To identify variables and clinically useful cut-off values with reproducible diagnostic accuracy for the prediction of ponies that subsequently developed laminitis when exposed to nutrient dense pasture. Methods: A cohort of predominantly Welsh and Dartmoor ponies from a closed herd was evaluated in March 2006 (n = 74) and March 2007 (n = 57). Ponies were categorised as never laminitic or previously laminitic according to reported laminitic history and as clinically laminitic (CL) if laminitis was observed within 3 months following evaluation. Body condition score (BCS), cresty neck score (CNS), girth and neck circumferences (NC), withers height, blood pressure and hoof surface temperature, and plasma insulin, glucose, triglyceride, leptin, cortisol, ACTH, uric acid and TNF-, concentrations were measured. Analysis of sensitivity, specificity and receiver operating characteristic curves was used to evaluate the diagnostic accuracy for a variable to predict CL ponies. Results: Variables with diagnostic accuracy for the prediction of CL ponies included insulin, leptin, BCS, CNS, and NC:height ratio. Specific cut-off values of insulin (>32 mu/l), leptin (>7.3 ng/ml), BCS (,7), CNS (,4) and NC:height ratio (>0.71) had reproducible diagnostic accuracy for the prediction of laminitis. Combining tests did not result in higher diagnostic accuracy than individual tests of insulin or leptin during either evaluation. Conclusions: Tests of insulin and leptin concentrations and measures of generalised (BCS) and localised (CNS or NC:height ratio) obesity were beneficial in the prediction of laminitic episodes. Potential relevance: These results highlight the importance of monitoring and reducing insulin concentration, and generalised and regional obesity in ponies to reduce risk of laminitis. [source]


    Relationship between presence of basidiomes, above-ground symptoms and root infection by Collybia fusipes in oaks

    FOREST PATHOLOGY, Issue 1 2000
    B. Maris
    Summary Collybia fusipes is a common cause of root rot on oak in the north of France. Collybia fusipes basidiomes can be as frequent on oaks in stands where no decline of the trees occurs compared with stands where the decline is chronic. This might be explained by differences in the amount of roots damaged by the parasite. To test that hypothesis, 430 oak trees, Quercus petraea, Quercus robur and Quercus rubra, located in six forests were selected. Half of them showed C. fusipes basidiomes at the trunk base. The association between presence of basidiomes and decline of affected trees depended on the forest. The level of infection of each tree by C. fusipes, as well as the crown appearance, the tree height : diameter at breast height ratio, age and sapwood width were determined. The presence of C. fusipes basidiomes was always associated with significant root infections. The crowns of the trees deteriorated with increasing level of root infection and the decline was severe only when the root damage was heavy. Although the decline of trees that were heavily damaged by C. fusipes was severe in some of the stands, in others, it was only mild, and so the differences in tree decline between the stands could not be attributed solely to differences in root infection severity. Trees damaged by C. fusipes seemed not to be subjected to more competition than their undamaged neighbour as reflected by a similar tree height: diameter at breast height ratio. [source]


    Host-specific aphid population responses to elevated CO2 and increased N availability

    GLOBAL CHANGE BIOLOGY, Issue 11 2005
    Erika A. Sudderth
    Abstract Sap-feeding insects such as aphids are the only insect herbivores that show positive responses to elevated CO2. Recent models predict that increased nitrogen will increase aphid population size under elevated CO2, but few experiments have tested this idea empirically. To determine whether soil nitrogen (N) availability modifies aphid responses to elevated CO2, we tested the performance of Macrosiphum euphorbiae feeding on two host plants; a C3 plant (Solanum dulcamara), and a C4 plant (Amaranthus viridis). We expected aphid population size to increase on plants in elevated CO2, with the degree of increase depending on the N availability. We found a significant CO2 N interaction for the response of population size for M. euphorbiae feeding on S. dulcamara: aphids feeding on plants grown in ambient CO2, low N conditions increased in response to either high N availability or elevated CO2. No population size responses were observed for aphids infesting A. viridis. Elevated CO2 increased plant biomass, specific leaf weight, and C : N ratios of the C3 plant, S. dulcamara but did not affect the C4 plant, A. viridis. Increased N fertilization significantly increased plant biomass, leaf area, and the weight : height ratio in both experiments. Elevated CO2 decreased leaf N in S. dulcamara and had no effect on A. viridis, while higher N availability increased leaf N in A. viridis and had no effect in S. dulcamara. Aphid infestation only affected the weight : height ratio of S. dulcamara. We only observed an increase in aphid population size in response to elevated CO2 or increased N availability for aphids feeding on S. dulcamara grown under low N conditions. There appears to be a maximum population growth rate that M. euphorbiae aphids can attain, and we suggest that this response is because of intrinsic limits on development time and fecundity. [source]


    Infrared Microscopic Imaging of Bone: Spatial Distribution of CO32,

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2001
    H. Ou-Yang
    Abstract This article describes a novel technology for quantitative determination of the spatial distribution of CO32, substitution in bone mineral using infrared (IR) imaging at ,6 ,m spatial resolution. This novel technology consists of an IR array detector of 64 64 elements mapped to a 400 ,m 400 ,m spot at the focal plane of an IR microscope. During each scan, a complete IR spectrum is acquired from each element in the array. The variation of any IR parameter across the array may be mapped. In the current study, a linear relationship was observed between the band area or the peak height ratio of the CO32, v3 contour at 1415 cm,1 to the PO43, v1,v3 contour in a series of synthetic carbonated apatites. The correlation coefficient between the spectroscopically and analytically determined ratios (R2 = 0.989) attests to the practical utility of this IR area ratio for determination of bone CO32, levels. The relationship forms the basis for the determination of CO32, in tissue sections using IR imaging. In four images of trabecular bone the average CO32, levels were 5.95 wt% (2298 data points), 6.67% (2040 data points), 6.66% (1176 data points), and 6.73% (2256 data points) with an overall average of 6.38 0.14% (7770 data points). The highest levels of CO32, were found at the edge of the trabeculae and immediately adjacent to the Haversian canal. Examination of parameters derived from the phosphate v1,v3 contour of the synthetic apatites revealed that the crystallinity/perfection of the hydroxyapatite (HA) crystals was diminished as CO32, levels increased. The methodology described will permit evaluation of the spatial distribution of CO32, levels in diseased and normal mineralized tissues. [source]


    Height and relative leg length as indicators of the quality of the environment among Mozambican juveniles and adolescents

    AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 2 2009
    Cristina Padez
    The growth status of Mozambique adolescents was assessed to test the hypothesis that relative leg length is a more sensitive indicator of the quality of the environment than the total height. The sample comprised 690 boys and 727 girls, aged between 9 and 17 years, from Maputo. It is divided between those living in the Centre of Maputo and those living in the slums on the periphery of the city. Height, weight, and sitting height were measured and the sitting height ratio was calculated. The hypothesis that relative leg length is more sensitive than total stature as an indicator of environmental quality is not uniformly confirmed. Overall, mean stature is greater for the centre group than the slum group, but relative leg length as measured by the sitting height ratio does not differ. Compared with African-American references (NHANES II), all centre girls, 9- to 14-year-old slum girls, all slum boys, and the oldest centre boys show relatively shorter legs. These findings show that within the Mozambique sample, relative leg length is not sensitive enough to distinguish the quality of the living environment. Mozambique was a colony of Portugal until 1975. Civil unrest and warfare characterized the late Colonial period and the postindependence period until a peace settlement was concluded in 1992. It is possible that all socioeconomic status groups within the country suffered sufficiently to reduce relative leg length compared with the better-off African-American reference sample. Possible genetic influences on relative leg length are also discussed. Am. J. Hum. Biol. 2009. 2008 Wiley-Liss, Inc. [source]


    Sensitivity improvement of circular dichroism detection in HPLC by using a low-pass electronic noise filter: Application to the enantiomeric determination purity of a basic drug

    CHIRALITY, Issue 2 2007
    Marie Lorin
    Abstract The quality control of chiral drugs requires the determination of their enantiomeric purity. Nowadays, circular dichroism (CD) spectroscopy is gaining increasing importance in pharmaceutical analysis because of the commercially available CD detector in liquid chromatography. The separation of the two enantiomers of a basic drug (efaroxan) was achieved by high performance liquid chromatography using an amylose-derivated column with both UV and CD detections. A baseline-resolved separation (resolution: 5) was obtained after optimization of the mobile phase composition with hexane-ethanol-diethylamine (90:10:0.05; v/v/v). The use of a commercial low-pass electronic noise filter of the CD signal has improved the signal-to-noise ratio by a factor twelve and allowed the quantitation of each enantiomer in the 1.25,300 ,g ml,1 concentration range. The CD linear calibration curve, expressed in terms of stereoisomer height ratio versus concentration ratio, was plotted over the 0.4,6% range. A correlation coefficient greater than 0.999 was obtained by least-squares regression and the limit of detection for the distomer/eutomer ratio was estimated at 0.14%. Although the method validation showed good repeatability on the retention times (RSD < 0.9%), on the peak height ratios (RSD < 8.7%) of each enantiomer only up to 99.2% enantiomeric purity was achieved. Chirality, 2006. 2006 Wiley-Liss, Inc. [source]


    Effects of mild aerobic physical exercise on membrane fluidity of erythrocytes in essential hypertension

    CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2003
    Kazushi Tsuda
    Summary 1.,The present study was undertaken to investigate the effects of aerobic physical exercise on membrane function in mild essential hypertension. 2.,Hypertensive patients were divided into an exercise group (n = 8) and a non-exercise (control) group (n = 8). Physical exercise within the intensity of the anaerobic threshold level was performed twice a week for 6 months. Membrane fluidity of erythrocytes was examined by means of electron paramagnetic resonance (EPR) and spin-labelling methods before and after the trial period in both groups. 3.,After physical exercise, blood pressure decreased significantly. 4.,Compared with the non-exercise group, in the exercise group both the order parameter (S) and the peak height ratio (ho/h -1) in the EPR spectra of erythrocytes were significantly reduced (S, 0.717 0.004 vs 0.691 0.008, respectively (n = 8), P < 0.05; ho/h -1, 5.38 0.06 vs 4.89 0.06, respectively (n = 8), P < 0.05). These findings indicated that exercise increased membrane fluidity and improved the membrane microviscosity of erythrocytes. 5.,There was no direct correlation between blood pressure reduction and the exercise-induced increase in membrane fluidity of erythrocytes. 6.,In the non-exercise (control) group, blood pressure and membrane fluidity were not changed after a 6 month follow-up period. 7., The results show that aerobic physical exercise increased erythrocyte membrane fluidity and improved the rigidity of cell membranes in hypertensive patients. The improvement of rheological properties of erythrocytes may explain, in part, the cellular mechanisms for the beneficial effects of physical exercise in hypertension. [source]


    An analytical method for cyclosporine using liquid chromatography,mass spectrometry

    BIOMEDICAL CHROMATOGRAPHY, Issue 2 2010
    Srividya V. Kanduru
    Abstract A liquid chromatographic mass spectrometric (LC-MS) assay has been developed for cyclosporine A (CyA) in rat plasma using amiodarone as internal standard (IS). Rat plasma (100,L) containing drug and IS were extracted using liquid,liquid extraction with 4,mL of 95:5 ether:methanol. After evaporation of the organic layer the residue was reconstituted with 500,L of water. Then the aqueous layer was transferred to LC-MS sample vials. A 10,L volume was injected. The analysis was performed on a C8 column 3.5,m (2.1 50,mm) heated to 60C with a mobile phase consisting of acetonitrile:methanol:0.2% NH4OH (60:20:20) at an isocratic flow-rate of 0.2,mL/min. The ions used for quantitation of CyA and IS were m/z 1202.8 and 645.9, with retention times of 3.35 and 4.72,min, respectively. Linear relationships (r2,>,0.99) were achieved between plasma or blood concentration and peak height ratios (drug:IS) over the concentration range 50,5000,ng/mL. The CV% and mean error were <19%. Based on validation data, the lower limit of quantification for the assay was 50,ng/mL. The reported assay method displayed high measures of linearity, sensitivity, reliability and precision, allowing its applicability in pharmacokinetic studies in rat. Copyright 2009 John Wiley & Sons, Ltd. [source]


    Determination of halofantrine and its main metabolite desbutylhalofantrine in rat plasma by high-performance liquid chromatography with on-line UV irradiation and peroxyoxalate chemiluminescence detection

    BIOMEDICAL CHROMATOGRAPHY, Issue 1 2009
    Abena Amponsaa-Karikari
    Abstract A sensitive, selective and reliable method has been developed and validated for the determination of halofantrine and its metabolite desbutylhalofantrine in rat plasma using 9,10-diphenylanthracene as an internal standard. The method is based on peroxyoxalate chemiluminescence detection of hydrogen peroxide produced from fused aromatic rings in the structures of halofantrine and desbutylhalofantrine upon UV irradiation. Using spiked rat plasma, good linear relationships were obtained for both halofantrine and desbutylhalofantrine between peak height ratios (vs internal standard) and their corresponding concentrations over a range of 0.01,0.8 g/mL with correlation coefficients of at least 0.997. The detection limits at signal-to-noise ratio of 3 using 0.2 mL of rat plasma were 1.5 and 1.4 ng/mL for halofantrine and desbutylhalofantrine, respectively. Relative standard deviations (n = 3) intra- and inter-day were between 0.5 and 5.4% for all the studied concentrations. Using this method with simple sample treatment, halofantrine and desbutylhalofantrine in rat plasma could be precisely determined without interference from endogenous substances. The method was successfully applied to the measurement of the time courses of plasma halofantrine concentration after oral administration of the drug (7 mg/kg) to rats. Copyright 2008 John Wiley & Sons, Ltd. [source]


    Sensitivity improvement of circular dichroism detection in HPLC by using a low-pass electronic noise filter: Application to the enantiomeric determination purity of a basic drug

    CHIRALITY, Issue 2 2007
    Marie Lorin
    Abstract The quality control of chiral drugs requires the determination of their enantiomeric purity. Nowadays, circular dichroism (CD) spectroscopy is gaining increasing importance in pharmaceutical analysis because of the commercially available CD detector in liquid chromatography. The separation of the two enantiomers of a basic drug (efaroxan) was achieved by high performance liquid chromatography using an amylose-derivated column with both UV and CD detections. A baseline-resolved separation (resolution: 5) was obtained after optimization of the mobile phase composition with hexane-ethanol-diethylamine (90:10:0.05; v/v/v). The use of a commercial low-pass electronic noise filter of the CD signal has improved the signal-to-noise ratio by a factor twelve and allowed the quantitation of each enantiomer in the 1.25,300 ,g ml,1 concentration range. The CD linear calibration curve, expressed in terms of stereoisomer height ratio versus concentration ratio, was plotted over the 0.4,6% range. A correlation coefficient greater than 0.999 was obtained by least-squares regression and the limit of detection for the distomer/eutomer ratio was estimated at 0.14%. Although the method validation showed good repeatability on the retention times (RSD < 0.9%), on the peak height ratios (RSD < 8.7%) of each enantiomer only up to 99.2% enantiomeric purity was achieved. Chirality, 2006. 2006 Wiley-Liss, Inc. [source]


    Anthropometric indices as predictors of the metabolic syndrome and its components in adolescents

    PEDIATRICS INTERNATIONAL, Issue 3 2010
    Christian Jung
    Abstract Background:, Overweight and related health problems are becoming increasingly recognized, especially in children and adolescents. For early screening, different anthropometrical measurements of obesity have been proposed to identify individuals at risk. We compared body mass index (BMI), BMI standard deviation score, waist circumference, waist-to-hip ratio (WHR), and waist/height ratio with respect to their power to predict the metabolic syndrome, its components and low-grade inflammation. Methods:, A total of 79 male Caucasian German adolescents (13,17 years) were studied. All anthropometrical measurements of obesity were recorded and blood samples drawn. Predictive power was estimated using receiver operating characteristic curves, by comparing the area under the curve (AUC). Results:, Except for WHR, all tested anthropometrical measurements of obesity showed comparably good AUC values for correct prediction, with the highest AUC for BMI (P < 0.001, AUC = 0.885 0.039). Superior prediction power was not observed for BMI standard deviation score, waist circumference, WHR or waist/height ratio. Furthermore, BMI was the best predictor of elevated C-reactive protein levels as a marker for low-grade inflammation (P < 0.001, AUC = 0.786 0.064). Conclusions:, In this cross-sectional study the well-established parameter BMI was shown to have the best predictive power to identify metabolic syndrome, its components and markers for low-grade inflammation. Newly developed parameters did not provide superior values. Future longitudinal studies are needed to compare these anthropometrical markers in larger cohorts, incorporating different age groups and ethnic backgrounds. [source]


    Effect of individualized weight-loss programmes on adiponectin, leptin and resistin levels in obese adolescent boys

    ACTA PAEDIATRICA, Issue 9 2009
    M Elloumi
    Abstract Aim:, We investigate the effects of a 2-month weight-loss programme on plasma levels of adiponectin, leptin and resistin in obese adolescent boys. Methods:, Twenty-one obese adolescent boys (BMI = 30.8 3.2 kg/m2) completed the weight-loss programme including: 1/ either energy restriction (R), 2/ or individualized exercise training at the point of maximum lipid oxidation (Lipoxmax) (E), 3/ or energy restriction and training (RE). Body composition, lipid oxidation and plasma levels of adiponectin, leptin and resistin were measured before and after intervention. Results:, Following the weight-loss programme, adolescents of the RE group showed an improvement of their body composition (p < 0.01), an increase in plasma adiponectin (+73.7%, p < 0.01) and a decrease in plasma leptin (,38.8%, p < 0.01) leading to an increase in adiponectine/leptin ratio (ALR, +144.4%, p < 0.01) higher than the R or E groups. E and RE groups only showed a similar significant increase in plasma resistin (p < 0.05) and a significant improvement of lipid oxidation rate at Lipoxmax (p < 0.01 and p < 0.001). In addition, in RE group, ALR is correlated with waist/hip and waist/height ratios, resistin level, homoeostasis mode assessment (HOMA-IR) index and Lipoxmax. Conclusion:, In obese adolescents boys, moderate exercise training completed at Lipoxmax and combined with energy restriction improves their ability to oxidize lipids, which is associated with a normalization of their adiponectin, leptin and resistin levels resulting in an improved insulin sensitivity, as attested by a higher ALR and a lower HOMA-IR. [source]


    Toward a Continuous Quality Improvement Paradigm for Hemodialysis Providers with Preliminary Suggestions for Clinical Practice Monitoring and Measurement

    HEMODIALYSIS INTERNATIONAL, Issue 1 2003
    Edmund G. Lowrie
    Background: Consensus processes using the clinical literature as the primary source for information generally drive projects to draft clinical practice guidelines (CPGs). Most such literature citations describe special projects that are not part of an organized quality management initiative, and the publication/review/consensus process tends to be long. This project describes an initiative to develop and explore a flexible and dedicated data-driven paradigm for deciding new CPGs that could be rapidly responsive to changing medical knowledge and practice. Methods: Candidate Clinical Practice Monitoring Measures (CPMM) were selected using a large, national database according to the natures and strengths of their associations with mortality risk among patients during 1994. Thresholds above or below which risk of death increased were evaluated for each CPMM using risk profile charts and spline functions. The fractions of patients outside of those thresholds in each dialysis unit (the %Var) were determined for the years 1993, 1994, and 1995. A standardized mortality ratio (SMR) was also determined for each year for each facility. The associations between the %Var and SMR were evaluated in several single-variable and multivariable statistical models. Results: Eleven CPMM were selected and evaluated based on their associations with death risk. These included the urea clearance x dialysis time product (Kt); the concentrations of albumin, potassium, phosphate, bicarbonate, hemoglobin, neutrophils, and lymphocytes in the blood; the body weight/height ratio; diastolic blood pressure; and vascular access type. Even though the CPMM were strongly associated with death risk among patients, the %Var were weakly and inconsistently associated with SMR among facilities. Conclusions: The paradigm was flexible, easy to implement, quickly executed, and potentially able to accommodate evolving medical practice assuming the availability of large database systems such as this. The primary associates of death risk were easily identified and the thresholds easily adopted. The SMR and %Var from the CPMM were only weakly associated, however, suggesting that one cannot be reliably predicted from the other. As such, quality management programs should likely monitor both the processes and outcomes of care among dialysis facilities. [source]


    Effects of folic acid on preschool children's appetite: Randomized triple-blind clinical trial

    PEDIATRICS INTERNATIONAL, Issue 5 2007
    NIKTA HATAMIZADEH
    Abstract Background: In recent years some Iranian pediatricians have used folic acid empirically as an appetite-enhancing drug in poor-appetite, low-weight children. Many parents have expressed their satisfaction with this treatment but until now no study has been done to confirm or exclude folic acid as an appetite enhancer. Methods: In order to determine if complementary folic acid has any effect on preschool children's appetite, 61 3,5-year-old children (27 girls and 34 boys) whose weight/age and weight/height ratios were below the 25 centile and whose parents regarded them as having poor appetite were randomly assigned to receive either folic acid (1 mg/day) or placebo for 20 days. The primary outcome measures were any appetite changes during and 1 month after the end of the intervention, measured by means of a questionnaire completed by parents on the 20th and 60th days. Secondary measures were mean weight gain on the 30th and 60th days. Results: Children who received folic supplement had a significantly better appetite on the 20th day than those who received placebo (mean difference of appetite score: 1.7; 95% confidence interval: 0.1,3.4; P = 0.04) and significantly more children receiving folic acid were reported to have increased appetite than the placebo group (P = 0.03). But 40 days after the end of the intervention there was no difference between the two groups. Weight gain did not significantly differ between groups. Conclusions: Although folic acid appears to improve preschool children's appetite, further study is necessary to determine whether it has any effect on growth as an adjunctive to management protocols of low appetite for undernourished children. [source]