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Different Experiments (different + experiment)
Selected AbstractsDynamic peroxide method for kLaO2 estimationJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2009Marcos Marcelino Abstract BACKGROUND: A reliable kLaO2 estimation methodology in bioreactors is a recurrent topic in the literature owing to the significance of this value, particularly in respirometric measurements. The most common methodologies for kLaO2 estimation consist of modeling the profile of dissolved oxygen (DO) obtained after a perturbation of the system aeration. Among them, the dynamic peroxide method (DPM), which consists of a small addition of peroxide hydrogen for a sudden increase in the DO level, is a promising methodology. RESULTS: This work studies the reliability of kLaO2 estimates using DPM. Different experiments were performed with sludge cultures enriched with heterotrophs, nitrifiers and polyphosphate accumulating organisms (PAO). The influence of several operational conditions (i.e. air flow, sludge concentration, H2O2 volume addition) on kLaO2 estimates was studied and the reliability of DPM was compared with the widely used reaeration methodology. An application of DPM in the assessment of oxygen surface transfer in a mechanically stirred bioreactor is described. CONCLUSION: DPM is a reliable methodology for kLaO2 estimation that can be successfully applied to heterotrophs, nitrifiers and PAO without observing any inhibitory effect ([H2O2] , 6 mg L,1). Copyright © 2009 Society of Chemical Industry [source] Community effects of praying mantids: a meta-analysis of the influences of species identity and experimental designECOLOGICAL ENTOMOLOGY, Issue 4 2002William F. Fagan Abstract ,1. Generalist arthropod predators are ubiquitous in terrestrial ecosystems but experimental studies have yielded little agreement as to their effects on prey assemblages. Drawing on results from a suite of experimental field studies, a meta-analysis was conducted of the impact of praying mantids (Mantodea: Mantidae) on arthropod assemblages in order to identify predictable and unpredictable effects of these extremely generalised predators. 2. Results across different experiments were synthesised using the log response ratio framework, with a focus on quantifying net mantid impacts on arthropod density across taxonomic orders and trophic levels of arthropods, paying special attention to the contribution of mantid species identity and experimental design variables, such as the use of cages, length of experiment, and manipulated mantid density. 3. Calculated on a per mantid-day basis, the net impacts of Tenodera sinensis on arthropod density were generally weaker but more predictable than the effects of Mantis religiosa. Mantids in general had weak negative effects on density for most taxa but exhibited strong negative and positive effects on some taxa. Tenodera sinensis tended to have negative effects on Homoptera, Diptera, and Hemiptera and herbivores as a group, however M. religiosa exhibited greater variation in response of different taxa that appeared to be affected more strongly by experimental design. The effects of Stagmomantis carolina tended to be negative or non-significant. 4. Experimental cages had little influence on either the sign or magnitude of net community impacts for T. sinensis, however cage experiments reversed the sign of the mean effect for two of six taxonomic orders when the experimental predator was M. religiosa. Cages also increased the variability of effect size greatly for M. religiosa but not for T. sinensis. 5. It was concluded that it is possible to use log response ratios to determine general, predictable trends in a well-studied system. Similar meta-analyses of generalist predator effects in other systems should produce predictions of how these predators influence food webs, an important step towards defining more clearly the influences of generalist predators on community structure and dynamics. [source] Brain Sterols in the AY-9944 Rat Model of Atypical Absence SeizuresEPILEPSIA, Issue 1 2002Miguel A. Cortez Summary: ,Purpose: The AY-9944 (AY)-treated rat is a reproducible and clinically relevant animal model of atypical absence seizures. AY inhibits cholesterol synthesis, but the relation between brain sterol levels and the spontaneously recurrent absence seizures has not been determined. Methods: Long,Evans hooded rats were treated every 6 days from postnatal day (P)2 to P20 with AY (7.5 mg/kg, s.c.) or saline. Electrodes were permanently implanted under pentobarbital anesthesia at P50. Spike-and-wave discharge (SWD) duration and amplitude were quantified at P55. Changes in brain sterols after AY were examined in three different experiments, looking at brain regions (experiment 1), recovery after stopping AY (experiment 2), or gender differences (experiment 3). Results: Experiment 1: AY caused spontaneously recurrent slow SWD that lasted 59 times longer and had a 3.2-fold higher amplitude than that in controls. At P55, brain cholesterol was reduced and 7-dehydrocholesterol was increased in all brain regions (p < 0.0001). Experiment 2: Four hundred days after stopping AY-9944 treatment (P420), brain sterol levels had returned to normal levels, but the AY-induced SWD lasted twice as long as at P55. Experiment 3: At P55, AY-induced changes in plasma and liver (but not brain) sterols were significantly more severe in females compared with males. Conclusions: AY-induced seizures appear to be related to AY-induced changes in brain sterols but persisted long after the sterols had returned to normal after the last AY injection. Hence, there appears to be a critical developmental window during which the AY must be given but after which the AY-induced change in brain sterols is no longer essential to sustaining the seizures. [source] Enhancing multisensory spatial orienting by brain polarization of the parietal cortexEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2010Nadia Bolognini Abstract Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that induces polarity-specific excitability changes in the human brain, therefore altering physiological, perceptual and higher-order cognitive processes. Here we investigated the possibility of enhancing attentional orienting within and across different sensory modalities, namely visual and auditory, by polarization of the posterior parietal cortex (PPC), given the putative involvement of this area in both unisensory and multisensory spatial processing. In different experiments, we applied anodal or sham tDCS to the right PPC and, for control, anodal stimulation of the right occipital cortex. Using a redundant signal effect (RSE) task, we found that anodal tDCS over the right PPC significantly speeded up responses to contralateral targets, regardless of the stimulus modality. Furthermore, the effect was dependant on the nature of the audiovisual enhancement, being stronger when subserved by a probabilistic mechanism induced by blue visual stimuli, which probably involves processing in the PPC. Hence, up-regulating the level of excitability in the PPC by tDCS appears a successful approach for enhancing spatial orienting to unisensory and crossmodal stimuli. Moreover, audiovisual interactions mostly occurring at a cortical level can be selectively enhanced by anodal PPC tDCS, whereas multisensory integration of stimuli, which is also largely mediated at a subcortical level, appears less susceptible to polarization of the cortex. [source] Some questions on dispersion of human exhaled droplets in ventilation room: answers from numerical investigationINDOOR AIR, Issue 2 2010C. Chen Abstract, This study employs a numerical model to investigate the dispersion characteristics of human exhaled droplets in ventilation rooms. The numerical model is validated by two different experiments prior to the application for the studied cases. Some typical questions on studying dispersion of human exhaled droplets indoors are reviewed and numerical study using the normalized evaporation time and normalized gravitational sedimentation time was performed to obtain the answers. It was found that modeling the transient process from a droplet to a droplet nucleus due to evaporation can be neglected when the normalized evaporation time is <0.051. When the normalized gravitational sedimentation time is <0.005, the influence of ventilation rate could be neglected. However, the influence of ventilation pattern and initial exhaled velocity on the exhaled droplets dispersion is dominant as the airflow decides the droplets dispersion significantly. Besides, the influence of temperature and relative humidity on the dispersion of droplets can be neglected for the droplet with initial diameter <200 ,m; while droplet nuclei size plays an important role only for the droplets with initial diameter within the range of 10 ,m,100 ,m. Practical Implications Dispersion of human exhaled droplets indoor is a key issue when evaluating human exposure to infectious droplets. Results from detailed numerical studies in this study reveal how the evaporation of droplets, ventilation rate, airflow pattern, initial exhaled velocity, and particle component decide the droplet dispersion indoor. The detailed analysis of these main influencing factors on droplet dispersion in ventilation rooms may help to guide (1) the selection of numerical approach, e.g., if the transient process from a droplet to a droplet nucleus due to evaporation should be incorporated to study droplet dispersion, and (2) the selection of ventilation system to minimize the spread of pathogen-laden droplets in an indoor environment. [source] Online temperature measurement and simultaneous diameter estimation of fibers by thermography of the spinline in the melt spinning processADVANCES IN POLYMER TECHNOLOGY, Issue 3 2004M. Golzar Abstract Online measurements of the temperature and the diameter of fibers in the melt spinning process of thermoplastics are discussed. The temperature and the diameter of fibers can be applied in many fields such as fiber formation modelling, cooling rate behavior (Nusselt number), and rheological investigations (apparent extensional viscosity) of polymers. The online measurements along the spinline were carried out with an infrared camera during the melt spinning process. Two different experiments were designed and carried out to find the correction factor, i.e., the emissivity. The results show that the emissivity correction factor depends on the polymer type and the fiber diameter. Usually the diameter of the fibers is measured by an instrument or by direct velocity measurements invoking the continuity equation. In this new approach the diameter is found directly by the evaluation of the measured temperature. Therefore only one apparatus, namely an infrared camera taking snapshots, is required to find the fiber diameter. The key of this method can be seen in the temperature difference between the fiber and the environment. A mathematical procedure was developed to estimate the diameter of the fiber from the distribution curve. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 176,185, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20008 [source] Reduction of Alcohol's Reinforcing and Motivational Properties by the Positive Allosteric Modulator of the GABAB Receptor, BHF177, in Alcohol-Preferring RatsALCOHOLISM, Issue 10 2009Paola Maccioni Background:, The positive allosteric modulators of the GABAB receptor, CGP7930 and GS39783, have been found to reduce alcohol self-administration in alcohol-preferring rats. The present study was designed to assess the effect of the newly synthesized positive allosteric modulator of the GABAB receptor, BHF177, on alcohol's reinforcing and motivational properties in selectively bred Sardinian alcohol-preferring (sP) rats. Methods:, sP rats were initially trained to respond on a lever [on a fixed ratio 4 (FR4) schedule of reinforcement] to orally self-administer alcohol (15%, v/v) or sucrose (1 to 3%, w/v) in daily 30-minute sessions. Once responding reached stable levels, rats were allocated to 2 different experiments: in the first experiment, rats were exposed to sessions with the FR4 schedule of reinforcement; in the second experiment, rats were exposed to sessions with a conventional progressive ratio (PR) schedule of reinforcement. In both experiments, the effect of BHF177 (0, 12.5, 25, and 50 mg/kg; i.g.) on responding for alcohol and sucrose (FR experiment: 1%, w/v; PR experiment: 3%, w/v) was determined. Results:, In the FR experiment, pretreatment with 25 and 50 mg/kg BHF177 produced a 30 and 45% reduction, respectively, in responding for alcohol. In the PR experiment, pretreatment with 50 mg/kg BHF177 resulted in a 35% reduction in breakpoint for alcohol (defined as the lowest response requirement not achieved by each rat and used as index of the motivational strength of alcohol). In both experiments, the effect of BHF177 on alcohol self-administration was specific, since responding for sucrose was unaltered by BHF177 pretreatment. Conclusions:, The present results extend to BHF177 the capacity of the 2 previously tested positive allosteric modulators of the GABAB receptor, CGP7930 and GS39783, to specifically suppress alcohol's reinforcing and motivational properties in alcohol-preferring rats. [source] Activation Of Mitogen Activated Protein Kinases (Mapks) In Response To High Glucose In Primary Sensory NeuronesJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 3 2000T Purves In diabetes high glucose stresses cells as a prelude to complications. The MAPKs are serine-threonine kinases, which are putative glucose stress transducers, comprising extracellular signal regulated kinases (ERKs), p38 and c-Jun, n-terminal kinases (JNKs). In 10 week streptozotocin-induced diabetic rats JNK activation was increased when compared to age matched controls. This study aimed to determine the signaling pathways activated in response to high glucose in adult sensory neurones in vitro. Cultures of adult rat dorsal root ganglia (DRG) were treated with 10mM, 25mM and 50mM glucose for 16 hours. MAPK activation was examined in Western blots using antibodies raised against phosphorylated and non-phosphorylated epitopes (results expressed as a ratio of phosphorylated to non-phosphorylated kinase). Glucose caused a concentration-dependent increase in phospho-p38 with a 1.6 fold increase at 25mM (0.77 ± 1.04) and a 2.4 fold increase at 50mM (1.18 ± 1.44) when compared to 10mM (0.49 ± 0.60) glucose. Phosphorylation of the p56 JNK isoform increased 2.4 fold (4.37 ± 3.59) and the p46 isoform 2.2 fold (1.95 ± 1.35) at 50mM glucose when compared to 10mM (p56 1.80 ± 0.99, p46 0.88 ± 0.31). ERK phosphorylation remained unchanged in 3 different experiments. Immunocytochemistry located these changes to neurones, rather than the small percentage of non-neurones that remain in culture. Transcription factor activation as a result of MAPK activation is being investigated using electrophoretic mobility shift assays. We conclude that the activation of MAPK pathways is involved in the response of neuronal cells to high glucose stress. [source] Different postharvest dehydration rates affect quality characteristics and volatile compounds of Malvasia, Trebbiano and Sangiovese grapes for wine productionJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2004Andrea Bellincontro Abstract Experiments were carried out using an innovative technology for dehydration based on the passage of air through a tunnel. It was possible to study the postharvest behaviour, at different rates of dehydration, of Malvasia, Trebbiano and Sangiovese grapes. Malvasia and Trebbiano grapes were picked with 17.5% SSC (soluble solids content), while Sangiovese grapes were harvested fully ripe with 26% SSC. All the grapes, in different experiments, were placed in the tunnel with an air speed of 1,1.5 m s,1, 42% RH (relative humidity) and a temperature of 21 °C. After 18 days the weight loss was 50 and 34% respectively in tunnel-treated Malvasia and Trebbiano grapes, while it was only 13,14% in control grapes (outside the tunnel: RH around 65% and temperature about 20 °C without ventilation). The SSC rose to 35 and 27% respectively in tunnel-treated Malvasia and Trebbiano grapes compared with 23 and 21% respectively in control grapes. In the case of Sangiovese grapes, after 7 days (the end of treatment) the weight loss was 20.5% in tunnel-treated grapes and 10.5% in control grapes. The SSC rose to 32% and the acidity increased from 4.8 to 5.8 g l,1 in tunnel-treated grapes compared with 29% and 5 g l,1 respectively in control grapes. Total phenols and anthocyanins almost doubled in tunnel-treated Sangiovese berries. Volatile compound analysis revealed a higher ethanol concentration in all tunnel-treated grapes but a lower concentration of ethyl acetate and acetic acid. Copyright © 2004 Society of Chemical Industry [source] Long-range JCH heteronuclear coupling constants in cyclopentane derivatives.MAGNETIC RESONANCE IN CHEMISTRY, Issue 1 2007Part II Abstract Here we report the detailed measurement of long-range heteronuclear spin,spin coupling constants, especially 2, 3JCH spin,spin couplings for eight different cyclopentane derivatives. These 2, 3JCH constants were shown to be a useful tool in the determination of the relative stereochemistry in these rings. The coupling constant measurements reported here are based on two different experiments: a 2D heteronuclear correlation experiment named G-BIRDR, X -CPMG-HSQMBC and the 2D-coupled gHSQC {1H- 13C} experiment Copyright © 2006 John Wiley & Sons, Ltd. [source] Capacity of model biobeds to retain and degrade mecoprop and isoproturonPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 10 2003Vibeke V Henriksen Abstract Biobeds are used to increase the adsorption and degradation of pesticide spillage on sites used for mixing and loading and for cleaning of sprayers. The adsorption and the rate of degradation of 14C-labelled isoproturon and mecoprop (MCPP) at concentrations from 0.0005 to 25 000 mg kg,1 were determined in biobed soil. Further leaching of the two herbicides was determined in a model biobed with a surface area of 2 m2. The biobed material showed enhanced ability to adsorb the two herbicides. Kd was 5.2 litre kg,1 for isoproturon and 1.6 litre kg,1 for MCPP in biobed material, which is higher than in natural soil. In different experiments with natural soil, Kd ranges from 0.07 to 0.6 litre kg,1 for MCPP and from 1.5 to 4.6 litre kg,1 for isoproturon in soils with varying organic carbon content. Degradation of MCPP was rapid at concentrations from 0.0005 to 500 mg kg,1, delayed at 5000 mg kg,1, and very slow at 25 000 mg kg,1. For isoproturon, the relative degradation was most rapid at the lowest concentration and decreasing with increasing concentrations. After 120 days, between 55% and 8% 14C was evolved as 14CO2 at concentrations between 0.0005 and 25 000 mg kg,1. The rate of evolution of 14CO2 indicated that degradation rates at low concentrations were of first-order and at higher concentrations of zero-order. Leaching of MCPP and isoproturon was determined in a newly established model biobed during a 2-year period. About 13% of applied MCPP and 1.4% of applied isoproturon leached out during the winter following the first autumn application (worst-case scenario). Leaching was completely prevented when the biobed had a well-developed grass cover and was covered during the winter. Copyright © 2003 Society of Chemical Industry [source] Positron experiments at the new positron beam facility NEPOMUC at FRM IIPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 10 2007C. Hugenschmidt Abstract The in-pile positron source NEPOMUC of the Munich research reactor FRM II delivers a low-energy positron beam of highest intensity. Different source potentials can be applied in order to vary the primary kinetic energy of the positrons in the range between 15 eV and 1 keV. The maximum yield of slow positrons is up to 4 × 107 and 5 × 108 moderated positrons per second, respectively. New instruments for beam diagnostics have been implemented for the determination of the positron intensity and for positron beam profile measurements. The long-term stability and the degradation of the platinum moderator as well as the recovery procedure were investigated. In the present arrangement of NEPOMUC's instrumentation the monoenergetic positron beam is magnetically guided to different experiments: a coincident Doppler broadening spectrometer (CDBS) and an analysis chamber for positron induced Auger electron spectroscopy (PAES). In addition, an apparatus for the production of the negatively charged positronium ion was connected to the beam line in order to investigate this bound leptonic system in collaboration with the Max-Planck Institute for nuclear physics. An overview of the beam performance, the current status of the positron beam facility and the experiments is presented. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A Method for Pooling Alleles from Different Genotyping ExperimentsANNALS OF HUMAN GENETICS, Issue 2 2005Y. S. Aulchenko Summary Single tandem repeat (STR) polymorphisms are widely used in linkage and association studies. One of the drawbacks of using these markers is that genetic data coming from different experiments cannot be easily pooled together, because both allele length and binning distance may change. As large studies with multiple series of subjects sequentially included become more and more common, there is an increasing interest in pooling the genetic data obtained in different experiments. Correct reconstruction of allelic correspondences between genotyping experiments is particularly crucial for association-oriented studies, such as candidate gene studies and genome-wide association studies in isolated populations. Here, we suggest a maximum-likelihood framework to find the best correspondence between alleles typed in different genotyping experiments. We also address the issue of goodness-of-fit and robustness. We perform a study simulating results obtained in a genome scan using 787 STR markers. The simulations show that the suggested method yields good results with respect to the error rate, even if the sizes of the samples to be pooled are as low as 10 subjects (3% errors), though only 9% of alleles pass our tests. As sample sizes increase to 250 subjects the proportion of alleles pooled reaches 96% with an error rate of <0.1%. [source] The effects of age and professional expertise on working memory performanceAPPLIED COGNITIVE PSYCHOLOGY, Issue 3 2009Elena Cavallini Differences in professional choice and experience may explain age differences in working memory performance of elderly people. The aim of this study was to examine whether expertise and prolonged practice in verbal and visuo-spatial abilities reduce age differences in laboratory working memory tasks. The effects of age and expertise on working memory performance were examined in three age groups in two different experiments. Firstly, the role of visuo-spatial expertise was analysed by examining age differences in architects. Secondly, people with extensive experience in verbal abilities (literary people) were tested in order to evaluate the effect of professional verbal experience. Architects and literary people outperformed a group of unselected age peers on tasks related to professional expertise only, but not on general working memory tests. There was no interaction between age and experience, suggesting that professional experience does not increase differences between experts and non experts and cannot modulate age-related effects. Copyright © 2008 John Wiley & Sons, Ltd. [source] Complex 1H,13C-NMR relaxation and computer simulation study of side-chain dynamics in solid polylysineBIOPOLYMERS, Issue 3 2005Alexey Krushelnitsky Abstract The side-chain dynamics of solid polylysine at various hydration levels was studied by means of proton spin,lattice relaxation times measurements in the laboratory and tilted (off-resonance) rotating frames at several temperatures as well as Monte Carlo computer simulations. These data were analyzed together with recently measured carbon relaxation data (A. Krushelnitsky, D. Faizullin, and D. Reichert, Biopolymers, 2004, Vol. 73, pp. 1,15). The analysis of the whole set of data performed within the frame of the model-free approach led us to a conclusion about three types of the side-chain motion. The first motion consists of low amplitude rotations of dihedral angles of polylysine side chains on the nanosecond timescale. The second motion is cis,trans conformational transitions of the side chains with correlation times in the microsecond range for dry polylysine. The third motion is a diffusion of dilating defects described in (W. Nusser, R. Kimmich, and F. Winter, Journal of Physical Chemistry, 1988, Vol. 92, pp. 6808,6814). This diffusion causes almost no reorientation of chemical bonds but leads to a sliding motion of side chains with respect to each other in the nanosecond timescale. This work evidently demonstrates the advantages of the simultaneous quantitative analysis of data obtained from different experiments within the frame of the same mathematical formalism, providing for the detailed description of the nature and geometry of the internal molecular dynamics. © 2005 Wiley Periodicals, Inc. Biopolymers 78: 129,139, 2005 This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] | ||||||||||||||||