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Selected AbstractsRegional Diastolic and Systolic Function by Strain Rate Imaging for the Detection of Intramural Viability during Dobutamine Stress Echocardiography in a Porcine Model of Myocardial InfarctionECHOCARDIOGRAPHY, Issue 5 2010Carsten Schneider M.D. The aim of this study was to evaluate diastolic and systolic strain rate measurements for differentiation of transmural/nontransmural infarction during dobutamine stress echocardiography (DSE). An ameroid constrictor was placed around the circumflex artery in 23 pigs inducing chronic vessel occlusion. Five pigs without constrictor served as controls. During high-dose DSE systolic strain rates (SRsys), systolic and postsystolic strain values (,sys, ,ps) and early and late diastolic strain rates (SRE and SRA) were determined. At week 6, animals were evaluated regarding myocardial fibrosis. Histology revealed nontransmural in 14 and transmural infarction in 9 animals. In controls, dobutamine induced a linear increase of SRsys to 12.3 ± 0.4 s,1 at 40 ,g/kg per minute (P = 0.001) and a linear decrease of SRE to ,6.6 ± 0.3 s,1 (P = 0.001). In the nontransmural group, SRsys, ,sys, ,ps at rest, and during DSE were higher and SRE was lower than in the transmural infarction group (P = 0.01). Best predictors for viability were SRsys (ROC 0.96, P = 0.0003), SRE at 10 ,g/kg per minute dobutamine stimulation (ROC 0.94, P = 0.001) and positive SR values during isovolumetric relaxation at 40 ,g/kg per minute dobutamine (ROC 0.86, P = 0.004). The extension of fibrosis correlated with SRsys at rest, ,sys at rest, and SRE at rest (P < 0.001). For the detection of viability similar diagnostic accuracies of SRE and SRsys were seen (sensitivity 93%/93%, specificity 96%/94%, respectively). Diastolic SR analysis seems to be equipotent for the identification of viable myocardium in comparison to systolic SR parameters and allows the differentiation of nontransmural from transmural myocardial infarction with high diagnostic accuracy. (Echocardiography 2010;27:552-562) [source] Using Capsaicin Modified Multiwalled Carbon Nanotube Based Electrodes and p -Chloranil Modified Carbon Paste Electrodes for the Determination of Amines: Application to Benzocaine and LidocaineELECTROANALYSIS, Issue 23 2008Roohollah Abstract The utilization of the capsaicin modified carbon nanotube modified basal-plane pyrolytic graphite electrode or p -chloranil modified carbon paste electrodes are presented for the determination of pharmaceutical compounds containing amine functionality, such as benzocaine and lidocaine. In detection of benzocaine at a capsaicin modified electrode, the guaiacol functional group is irreversibly electrochemically oxidized to form the o -quinone derivative which then undergoes nucleophilic attack by the aromatic amine group in benzocaine via a 1,4-Michael addition mechanism forming a catechol-amine adduct. The electrochemically initiated formation of the capsaicin-benzocaine adduct causes a linear decrease in the voltammetric signal corresponding to capsaicin which correlates to the added concentration of benzocaine. [source] Morphological development and nutritive value of herbage in five temperate grass species during primary growth: analysis of time dynamicsGRASS & FORAGE SCIENCE, Issue 2 2009Abstract In a 2-year field experiment, morphological development and measures of the nutritive value of herbage for livestock during primary growth in Meadow foxtail, Tall oatgrass, Cocksfoot, Perennial ryegrass and Yorkshire fog were investigated. All measured variables were affected significantly by both species and sampling date, and their interaction (P < 0·001), in the period of primary growth. Changes with time in mean stage weight for Meadow foxtail and Cocksfoot were different from the other species due to their indeterminate growth habits. Mean stage weight of Tall oatgrass and Yorkshire fog increased more rapidly than that of Perennial ryegrass with time. Changes in mean stage weight with time were described by linear, parabolic and sigmoid relationships. Crude protein (CP) concentration of herbage was higher for Cocksfoot and Meadow foxtail than for Perennial ryegrass. A parabolic relationship of CP concentration with time was typical for all the species. Concentrations of neutral-detergent fibre (NDF) and acid-detergent fibre (ADF) in herbage of the species differed most during the mid-period of primary growth. Their increases with time showed curvilinear (sigmoid and parabolic) relationships. Perennial ryegrass had lower concentrations of both NDF and ADF in herbage than the other species. Differences between the in vitro dry matter (DM) digestibility among the grasses increased in mid- and late periods of primary growth. Perennial ryegrass had higher values for in vitro DM digestibility but the difference from other species was small in the early period of primary growth and from cocksfoot in the late period of primary growth. In vitro DM digestibility showed, in most cases, a sigmoid and, in others, a linear decrease with time. Principal component analysis showed that perennial ryegrass and meadow foxtail were the most distinctive of the species in characteristics relating to morphological development and the nutritive value of herbage to livestock. [source] Chronic effects of low to moderate alcohol consumption on structural and functional properties of the brain: beneficial or not?,HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 3 2009Marinus N. Verbaten Abstract Objective Some studies suggest that the effects of low to moderate drinking (about 1,3 standard glasses of alcohol per day) on the brain and cognitive performance are positive. In the present study this hypothesis is investigated. Methods For this purpose studies on the effects of low to moderate drinking on brain structure (Magnetic Resonance Induction (MRI) studies) and on cognitive performance were analysed and discussed Results In MRI studies, a linear negative effect of alcohol consumption on brain volume was found. Furthermore, a linear decrease in grey matter concurring with a linear increase in white matter volumes as a function of number of drinks was reported in males, but not in females. Only in elderly low to moderate drinkers (aged,>,65 years) there appeared to be an U-shaped relationship between alcohol consumption and white matter integrity (grade) on the one hand and cognition on the other hand. Conclusions The changes reported in brain shrinkage, grey matter and white matter volume, as a result of low to moderate alcohol consumption sooner offer support for the contention that such drinking decreases brain health than for its beneficial effect. An exception might hold for elderly light and moderate drinkers where less white matter damage was found than in abstainers concurring with better cognitive performance. However, methodological problems impose limits on this conclusion. Copyright © 2009 John Wiley & Sons, Ltd. [source] Small-angle neutron scattering investigation of plastically deformed stainless steelJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3-1 2003Vassily Lebedev The microstuctural evolution of plastically deformed steels has been studied by small-angle neutron scattering at ambient temperature in the range of momentum transfer q = (4,/,)sin(,/2) = 0.01,5 nm,1 where , is neutron wavelength and , is the scattering angle. Samples of austenite stainless steels were pulled on a standard bench to cause a plastic deformation, S = 0,60%, up to the fracture of the material. As a result of the deformation an increase of an order of magnitude was observed in the scatterred intensity I(q)~1/[1+(qRC)2](6- Ds)/2. The analysis of the I(q) distribution has shown the surface fractal nature of the observed nano-scale structures. The evolution of internal surface via intensive growth of pores (size RC~20,40 nm) was found and a linear decrease of the surface fractal dimension 2.9,Ds(S),2.1 was observed. These findings can be used to design the fracture criteria for materials of industrial application. [source] The Potential Use of a Silicon Source as a Component of an Ecological Management of Coffee PlantsJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2008J. C. Martinati Abstract Coffee is one of the most important agricultural export commodities in the world and it represents the main export from some developing countries. Therefore, the development of new methods of coffee management that improves production without causing any damage to the environment is an attractive alternative for producers. Much effort has been invested towards understanding the mode of action of compounds that can induce resistance against several pathogens without injuring the environment. Many researches have considered silicon efficient in avoiding plant pathogen penetration and development. Our aim was to verify the effect of potassium silicate and calcium/magnesium silicate in the development of coffee seedlings (Coffea arabica cv. Mundo Novo) as well as to evaluate the incidence of coffee leaf rust development under greenhouse conditions. The experiment was a completely randomized design with 12 treatments with 10 plants per treatment. The treatments were 0, 0.25, 1.25, 2.5, 4 and 5 ,m of Si for each source of silicon incorporated into the soil. The seedlings were inoculated with a urediniospores suspension of Hemileia vastatrix (2 mg/ml) at the seventh month after planting (six pair of leaves). Evaluations were performed by counting the number of lesions per leaf. The statistical analysis showed that the number of lesions reduced by up to 66% at the highest silicon dose when compared to the number of lesions in control plants. Infected plants were found to have a linear decrease of lesions with the increase of silicate concentration. The lowest number of lesions per leaf area was observed in plants that received 5 ,m of Si from potassium silicate. This result indicates the use of silicon as an alternative for an ecological management system for coffee disease protection. [source] Synthesis and properties of gradient copolymers based on 2-phenyl-2-oxazoline and 2-nonyl-2-oxazolineJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 23 2009Hanneke M. L. Lambermont-Thijs Abstract In this study, the structure,property relationships for a series of statistical 2-nonyl-2-oxazoline (NonOx) and 2-phenyl-2-oxazoline (PhOx) copolymers were investigated for the first time. The copolymerization kinetics were studied and the reactivity ratios were calculated to be rNonOx = 7.1 ± 1.4 and rPhOx = 0.02 ± 0.1 revealing the formation of gradient copolymers. The synthesis of a systematical series of NonOx,PhOx copolymers is described, whereby the amount of NonOx was increased in steps of 10 mol %. The thermal and surface properties were investigated for this series of well-defined copolymers. The thermal properties revealed a linear decrease in glass transition temperature for copolymers containing up to 39 wt % NonOx. Furthermore, the melting temperature of the copolymers containing 0 to 55 wt % PhOx linearly decreased most likely due to disturbance of the NonOx crystalline domains by incorporation of PhOx in the NonOx part of the copolymer. The surface energies of spincoated polymer films revealed a strong decrease in surface energy upon incorporation of NonOx in the copolymers due to strong phase separation between NonOx and PhOx allowing the NonOx chains to orient to the surface. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6433,6440, 2009 [source] Effects of Alcohol on Performance on a Distraction Task During Simulated DrivingALCOHOLISM, Issue 4 2009Allyssa J. Allen Background:, Prior studies report that accidents involving intoxicated drivers are more likely to occur during performance of secondary tasks. We studied this phenomenon, using a dual-task paradigm, involving performance of a visual oddball (VO) task while driving in an alcohol challenge paradigm. Previous functional MRI (fMRI) studies of the VO task have shown activation in the anterior cingulate, hippocampus, and prefrontal cortex. Thus, we predicted dose-dependent decreases in activation of these areas during VO performance. Methods:, Forty healthy social drinkers were administered 3 different doses of alcohol, individually tailored to their gender and weight. Participants performed a VO task while operating a virtual reality driving simulator in a 3T fMRI scanner. Results:, Analysis showed a dose-dependent linear decrease in Blood Oxygen Level Dependent activation during task performance, primarily in hippocampus, anterior cingulate, and dorsolateral prefrontal areas, with the least activation occurring during the high dose. Behavioral analysis showed a dose-dependent linear increase in reaction time, with no effects associated with either correct hits or false alarms. In all dose conditions, driving speed decreased significantly after a VO stimulus. However, at the high dose this decrease was significantly less. Passenger-side line crossings significantly increased at the high dose. Conclusions:, These results suggest that driving impairment during secondary task performance may be associated with alcohol-related effects on the above brain regions, which are involved with attentional processing/decision-making. Drivers with high blood alcohol concentrations may be less able to orient or detect novel or sudden stimuli during driving. [source] INFLUENCE OF CELL SIZE AND CELL WALL VOLUME FRACTION ON FAILURE PROPERTIES OF POTATO AND CARROT TISSUEJOURNAL OF TEXTURE STUDIES, Issue 1 2005ARTUR ZDUNEK ABSTRACT This article presents the influence of cell size and cell wall volume fraction on the failure parameters of potato tuber and carrot tissue. Confocal scanning laser microscope was used for obtaining images of the cell structure of the tissues. The mean cell face area and the cell wall volume fraction obtained from the images was compared with work to failure, failure stress, failure strain and secant modulus obtained in a compression test of potato and carrot tissue at two strain rates. Bigger cells and less amount of cell wall material weakened the tissue, which was visible as a linear decrease in the parameters: work to failure, failure stress and failure strain. There were differences between potato and carrot in the secant modulus. For carrot, the secant modulus changed with microstructural parameters, whereas for potato, the secant modulus did not depend on these values. The strain rate decreases all the failure properties for potato. For carrot, only the work to failure was affected by the strain rate. [source] Low-Loss Microwave Dielectrics in the Spinel-Structured (Mg1,xNix)Al2O4 Solid SolutionsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2010Cheng-Liang Huang Solid solutions of (Mg1,xNix)Al2O4 (x=0,1) have been prepared using the solid-state reaction method and their dielectric properties were measured at microwave frequencies. Formation of single-phase spinel-structured solid solutions was confirmed by X-ray diffraction analysis throughout the entire compositional range, and the measured lattice parameters varied linearly from 8.0810 Å at x=0 (MgAl2O4) to 8.0445 Å at x=1 (NiAl2O4) leading to a linear decrease in the unit cell volume from 527.71 to 520.59 Å3. The ionic polarizability obtained, however, increased with the increase of x to a maximum at x=0.25 and decreased thereafter. It shows only a small variance in the ,r with Ni substitution for Mg and a maximum ,r of 8.21 was achieved for (Mg0.75Ni0.25)Al2O4 in response to the highest ionic polarizability and relative density. However, the Q×f value can be significantly promoted up to a maximum value of 130 000 GHz (measured at 15.4 GHz) at x=0.25. In addition, substitution of Mg by Ni also helps to decline the ,f value from ,65 ppm/°C at x=0 to ,53.5 ppm/°C at x=0.25. [source] Salt-Induced Depression of Lower Critical Solution Temperature in a Surface-Grafted Neutral Thermoresponsive PolymerMACROMOLECULAR RAPID COMMUNICATIONS, Issue 9 2006Young K. Jhon Abstract Summary: Quartz crystal microbalance with dissipation monitoring (QCM-D) is employed to determine the effect of salt on the volume phase transition of thermoresponsive polymer brushes. Changes in mass and viscoelasticity of poly(N -isopropylacrylamide) (PNIPAM) layers grafted from a QCM-D crystal are measured as a function of temperature, upon contact with aqueous solutions of varying salt concentrations. The phase-transition temperature of PNIPAM brushes, TC,graft, quantified from the QCM-D measurements is found to decrease as the concentration of salt is increased. This phenomenon is explained by the tendency of salt ions to affect the structure of water molecules (Hofmeister effect). However, in contrast to the linear decrease in phase-transition temperature upon increasing salt concentration observed for free PNIPAM, the trend in TC,graft for PNIPAM brushes is distinctively non-linear. Schematic representation of the effect of salt concentration on the phase transition behavior of thermoresponsive polymer brushes. [source] Mn and Si influence on the hyperfine properties of the fcc and hcp phases in the Fe,Mn and Fe,Mn,Si systemsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2009Javier Martínez Abstract A study of the hyperfine properties of the fcc and hcp phases of the Fe,Mn and Fe,Mn,Si systems, performed on a systematic and accurate set of samples belonging to the 15 at% to 30 at% Mn and 0 at% to 12 at% Si composition ranges, is presented. The samples were characterized using Conversion Electron Mössbauer Spectroscopy. The evolution with the Mn and Si contents of the hyperfine parameters of both phases has been determined. A constancy of the isomer shift parameter of the hcp phase with both constituents of the alloy was observed. While constancy and a linear decrease of the isomer shift values of the fcc phase with Mn and Si, respectively, were determined. The magnetic hyperfine field of the fcc phase presents two different values depending on the Mn content in the binary system and a decrease with the addition of Si when the ternary alloy is considered. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] AlGaN metal-semiconductor-metal structure for pressure sensing applicationsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2006Z. Hassan Abstract We report on the effects of hydrostatic pressure on an Alx Ga1,xN metal-semiconductor-metal (MSM) structure with Ni Schottky contacts. Structural, optical, and electrical analysis of the Alx Ga1,xN film were carried out using atomic force microscopy (AFM), high resolution X-ray diffraction (HRXRD), Raman, UV-visible spectroscopy, and Hall effect measurements. The AlN mole fraction in this film was determined to be about 24%. Current-voltage (I-V) measurements of the MSM structure under hydrostatic pressure indicated a linear decrease of current with pressure. The decrease of the current under pressure was attributed to an increase in barrier height, tentatively attributed to a combination of piezoelectric and band structure effects. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Control Charts for Monitoring Field Failure DataQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 7 2006Robert G. Batson Abstract One responsibility of the reliability engineer is to monitor failure trends for fielded units to confirm that pre-production life testing results remain valid. This research suggests an approach that is computationally simple and can be used with a small number of failures per observation period. The approach is based on converting failure time data from fielded units to normal distribution data, using simple logarithmic or power transformations. Appropriate normalizing transformations for the classic life distributions (exponential, lognormal, and Weibull) are identified from the literature. Samples of size 500 field failure times are generated for seven different lifetime distributions (normal, lognormal, exponential, and four Weibulls of various shapes). Various control charts are then tested under three sampling schemes (individual, fixed, and random) and three system reliability degradations (large step, small step, and linear decrease in mean time between failures (MTBF)). The results of these tests are converted to performance measures of time to first out-of-control signal and persistence of signal after out-of-control status begins. Three of the well-known Western Electric sensitizing rules are used to recognize the assignable cause signals. Based on this testing, the ,X -chart with fixed sample size is the best overall for field failure monitoring, although the individual chart was better for the transformed exponential and another highly-skewed Weibull. As expected, the linear decrease in MTBF is the most difficult change for any of the charts to detect. Copyright © 2005 John Wiley & Sons, Ltd. [source] DNA markers for estimation of inbreeding depression and heterosis in the guppy Poecilia reticulataAQUACULTURE RESEARCH, Issue 11 2003Takahito Shikano Abstract Molecular markers have significant potential for use in precise breeding programmes in aquaculture. This paper reviews the use of DNA markers to estimate inbreeding depression and heterosis in the guppy Poecilia reticulata. Full-sib matings revealed that inbreeding causes declines in survival and salinity tolerance, but not in undwarfism, growth and high water temperature tolerance, indicating the effects of inbreeding differ among fitness-related traits. Salinity tolerance was used to quantify the level of inbreeding depression and heterosis because the trait is strongly sensitive to inbreeding and shows a linear decrease with an increase in inbreeding coefficient. A positive correlation was observed between heterozygosity at microsatellite loci and salinity tolerance among 17 guppy populations. This indicates that heterozygosity estimated from microsatellites is a useful indicator for the estimation of inbreeding depression, suggesting that overall heterozygosity is important for fitness-related traits that show inbreeding depression. Use of DNA markers to estimate the amount of heterosis in various strain combinations was examined using diallele and reciprocal crosses among four domestic strains. The amount of heterosis differed among the strain combinations and correlated with Nei's genetic distance measured by microsatellites and also by dissimilarity using random amplified polymorphic DNA (RAPD) analysis. This indicates that microsatellite and RAPD markers are useful for estimating the amount of heterosis in various strain combinations, further suggesting that the amount of heterosis depends on the genetic differences between the strains. The present study showed that DNA markers are useful tools for estimating inbreeding depression and heterosis in guppy breeding. [source] Impact of Flooding on the Species Richness, Density and Composition of Amazonian Litter-Nesting AntsBIOTROPICA, Issue 5 2009Amy L. Mertl ABSTRACT Litter-nesting ants are diverse and abundant in tropical forests, but the factors structuring their communities are poorly known. Here we present results of the first study to examine the impact of natural variation in flooding on a highly diverse (21 genera, 77 species) litter-nesting ant community in a primary Amazonian forest. Fifty-six 3 × 3 m plots experiencing strong variation in flooding and twenty-eight 3 × 3 m terra firme plots were exhaustively searched for litter-nesting ants to determine patterns of density, species richness and species composition. In each plot, flooding, litter depth, twig availability, canopy cover, plant density, percent soil nitrogen, carbon, and phosphorus were measured. Degree of flooding, measured as flood frequency and flood interval, had the strongest impact on ant density in flooded forest. Flooding caused a linear decrease in ant abundance, potentially due to a reduction of suitable nesting sites. However, its influence on species richness varied: low-disturbance habitat had species richness equal to terra firme forest after adjusting for differences in density. The composition of ant genera and species varied among flood categories; some groups known to contain specialist predators were particularly intolerant to flooding. Hypoponera STD10 appeared to be well-adapted to highly flooded habitat. Although flooding did not appear to increase species richness or abundance at the habitat scale, low-flooding habitat contained a mixture of species found in the significantly distinct ant communities of terra firme and highly flooded habitat. [source] Infants' Attention to Patterned Stimuli: Developmental Change From 3 to 12 Months of AgeCHILD DEVELOPMENT, Issue 3 2006Mary L. Courage To examine the development of look duration as a function of age and stimulus type, 14- to 52-week-old infants were shown static and dynamic versions of faces, Sesame Street material, and achromatic patterns for 20 s of accumulated looking. Heart rate was recorded during looking and parsed into stimulus orienting, sustained attention, and attention termination phases. Infants' peak look durations indicated that prior to 26 weeks there was a linear decrease with age for all stimuli. Older infants' look durations continued to decline for patterns but increased for Sesame Street and faces. Measures of heart rate change during sustained attention and the proportion of time spent in each phase of attention confirmed infants' greater engagement with the more complex stimuli. [source] Optimization of Reaction Conditions for Enzymatic Viscosity Reduction and Hydrolysis of Wheat Arabinoxylan in an Industrial Ethanol Fermentation ResidueBIOTECHNOLOGY PROGRESS, Issue 2 2006Hanne R. Sørensen This study examined enzyme-catalyzed viscosity reduction and evaluated the effects of substrate dry matter concentration on enzymatic degradation of arabinoxylan in a fermentation residue, "vinasse", resulting from industrial ethanol manufacture on wheat. Enzymatic catalysis was accomplished with a 50:50 mixture of an enzyme preparation from Humicola insolens, Ultraflo L, and a cellulolytic enzyme preparation from Trichoderma reesei, Celluclast 1.5 L. This enzyme mixture was previously shown to exhibit a synergistic action on arabinoxylan degradation. The viscosity of vinasse decreased with increased enzyme dosage and treatment time at pH 5, 50 °C, 5 wt % vinasse dry matter. After 24 h of enzymatic treatment, 76,84%, 75,80%, and 43,47%, respectively, of the theoretically maximal arabinose, xylose, and glucose releases were achieved, indicating that the viscosity decrease was a result of enzyme-catalyzed hydrolysis of arabinoxylan, ,-glucan, and cellulose. In designed response surface experiments, the optimal enzyme reaction conditions with respect to pH and temperature of the vinasse, the vinasse supernatant (mainly soluble material), and the vinasse sediment (mainly insoluble substances) varied from pH 5.2,6.4 and 41,49 °C for arabinose release and from pH 4.9,5.3 and 42,46 °C for xylose release. Even though only limited hydrolysis of the arabinoxylan in the vinasse sediment fraction was obtained, the results indicated that the same enzyme activities acted on the arabinoxylan in the different vinasse fractions irrespective of the state of solubility of the substrate material. The levels of liberated arabinose and xylose increased with increased dry matter concentration during enzymatic hydrolysis in the vinasse and the vinasse supernatant, but at the same time, increased substrate dry matter concentrations gave corresponding linear decreases in the hydrolytic efficiency as evaluated from levels of monosaccharide release per weight unit dry matter. The study thus documents that enzymatic arabinoxylan hydrolysis of the vinasse significantly decreases the vinasse viscosity and that a compromise in the dry matter must be found if enzymatic efficiency must be balanced with monosaccharide yields. [source] | |||||||||||||||||||||||||