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Kinds of Single Terms modified by Single Selected AbstractsUncertainty and multiple objective calibration in regional water balance modelling: case study in 320 Austrian catchmentsHYDROLOGICAL PROCESSES, Issue 4 2007J. Parajka Abstract We examine the value of additional information in multiple objective calibration in terms of model performance and parameter uncertainty. We calibrate and validate a semi-distributed conceptual catchment model for two 11-year periods in 320 Austrian catchments and test three approaches of parameter calibration: (a) traditional single objective calibration (SINGLE) on daily runoff; (b) multiple objective calibration (MULTI) using daily runoff and snow cover data; (c) multiple objective calibration (APRIORI) that incorporates an a priori expert guess about the parameter distribution as additional information to runoff and snow cover data. Results indicate that the MULTI approach performs slightly poorer than the SINGLE approach in terms of runoff simulations, but significantly better in terms of snow cover simulations. The APRIORI approach is essentially as good as the SINGLE approach in terms of runoff simulations but is slightly poorer than the MULTI approach in terms of snow cover simulations. An analysis of the parameter uncertainty indicates that the MULTI approach significantly decreases the uncertainty of the model parameters related to snow processes but does not decrease the uncertainty of other model parameters as compared to the SINGLE case. The APRIORI approach tends to decrease the uncertainty of all model parameters as compared to the SINGLE case. Copyright © 2006 John Wiley & Sons, Ltd. [source] EFFECTS OF A SINGLE, SHORT INTRAVENOUS DOSE OF ACETYL- l -CARNITINE ON PATTERN-REVERSAL VISUAL-EVOKED POTENTIALS IN CIRRHOTIC PATIENTS WITH HEPATIC ENCEPHALOPATHYCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 1-2 2006Massimo Siciliano SUMMARY 1In animals and in cultured neurons, l -carnitine and acetyl- l -carnitine (ALCAR) have been shown to counteract some of the toxic effects of ammonia. In order to detect similar properties in humans, we studied neuronal function after ALCAR administration in cirrhotics with hepatic encephalopathy (HE). 2Eighteen cirrhotic patients with persistent HE and hyperammonaemia were investigated in the present study and six subjects with a prior transient ischaemic attack were used as controls. 3The prominent positive component that occurs approximately 100 msec after the pattern reversal (P100) latencies of visual-evoked potentials were used to evaluate neuronal function. At first, the P100 latency was measured in six cirrhotic patients with HE and in the six controls before the administration of 0.5 g ALCAR in 50 mL isotonic saline (infusion rate 10 mL/min) and 15, 30, 60 and 90 min later. 4A significant reduction in P100 latencies was identified 30 min after ALCAR infusion in HE patients, whereas no differences were observed in controls. 5Thereafter, the P100 latency was evaluated in the 12 other cirrhotic patients with HE only before and 30 min after ALCAR infusion. The mean of the P100 latencies measured in these subjects was significantly shorter after ALCAR infusion compared with values obtained before ALCAR administration (mean (SD) 130.78 5.50 vs 136.08 6.45 msec, respectively; P = 0.0013). 6The present study suggests that a single intravenous dose of ALCAR may transiently improve neuronal function in cirrhotic patients with persistent HE and hyperammonaemia. [source] Single Left Ventricle and PheochromocytomaCONGENITAL HEART DISEASE, Issue 5 2008Yat W. Cheung MD ABSTRACT We report a patient born with a Holmes heart who was later diagnosed with pheochromocytoma in her teenage years. A review of the literature showed only two such cases reported. The findings of these two rare conditions simultaneously in several individuals is suggestive of an association. [source] Single mechano-gated channels activated by mechanical deformation of acutely isolated cardiac fibroblasts from ratsACTA PHYSIOLOGICA, Issue 3 2010A. Kamkin Abstract Aim:, Mechanosensitive conductances were reported in cardiac fibroblasts, but the properties of single channels mediating their mechanosensitivity remain uncharacterized. The aim of this work was to investigate single mechano-gated channels (MGCs) activated by mechanical deformations of cardiac fibroblasts. Methods:, Currents through single MGCs and mechanosensitive whole-cell currents were recorded from isolated rat atrial fibroblasts using the cell-attached and whole-cell patch-clamp configurations respectively. Defined mechanical stress was applied via the patch pipette used for the whole-cell recordings. Results:, Under resting conditions occasional short openings of two types of single MGCs with conductances of 43 and 87 pS were observed. Both types of channels displayed a linear current,voltage relationship with the reversal potential around 0 mV. Small (1 ,m) mechanical deformations affected neither single nor whole-cell mechano-gated currents. Cell compressions (2, 3 and 4 ,m) augmented the whole-cell currents and increased the frequency and duration of single channel openings. Cell stretches (2, 3 and 4 ,m) inactivated the whole-cell currents and abolished the activity of single MGCs. Gd3+ (8 ,m) blocked the whole-cell currents within 5 min. No single channel activity was observed in the cell-attached mode when Gd3+ was added to the intrapipette solution. Cytochalasin D and colchicine (100 ,m each) completely blocked both the whole-cell and single channel currents. Conclusions:, These findings show that rat atrial fibroblasts express two types of MGCs whose activity is governed by cell deformation. We conclude that fibroblasts can sense the direction of applied stress and contribute to mechano-electrical coupling in the heart. [source] Silicon transport under rotating and combined magnetic fields in liquid phase diffusion growth of SiGeCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2010N. Armour Abstract The effect of applied rotating and combined (rotating and static) magnetic fields on silicon transport during the liquid phase diffusion growth of SiGe was experimentally studied. 72-hour growth periods produced some single crystal sections. Single and polycrystalline sections of the processed samples were examined for silicon composition. Results show that the application of a rotating magnetic field enhances silicon transport in the melt. It also has a slight positive effect on flattening the initial growth interface. For comparison, growth experiments were also conducted under combined (rotating and static) magnetic fields. The processed samples revealed that the addition of static field altered the thermal characteristics of the system significantly and led to a complete melt back of the germanium seed. Silicon transport in the melt was also enhanced under combined fields compared with experiments with no magnetic field. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Single cause, polymorphic neuronal migration disorders: an animal modelDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 10 2000Glenn D Rosen PhD Injury to the developing cortical plate can result in a variety of neuronal migration disorders. The results are reported of experimental research aimed at determining whether these different types of neocortical malformations are the consequence of comparable injury of varying intensity. Freezing probes were placed on the skulls of 44 newborn rats (age equivalent to 4 to 5 months of gestation in humans) and induced either one or two freezing injuries of durations ranging from 2 to 20 seconds. A variety of cortical malformations including minor laminar dysplasias, molecular layer ectopias, microgyria, and porencephalic cysts were seen in the brains of these animals when they were examined on postnatal day (P)2, P21, and P60. The severity of the malformation was directly related to the strength (number of hits and duration) of the freezing injury. These results suggest that a single etiologic event of varying severity during neuronal migration to the neocortex can induce widely disparate malformations of the cortex. [source] Coarse Grained Molecular Dynamics Simulation of Electromechanically-Gated DNA Modified Conical NanoporesELECTROANALYSIS, Issue 3 2008Lajos Höfler Abstract Nanopore-based devices are emerging as tools for single molecule manipulation, characterization and chemical analysis. Single or random arrays of chemically modified nanopores have been established as platforms for selective chemical and biosensing. However, it is little known about the orientation and behavior of surface tethered species in the nanopore environment as function of applied transpore voltages. In this study we report on coarse grained modeling of short (5-, 15-mer) DNA modified conical gold nanopores subjected to electrical field gradients of 5 and 50,mV/nm. An electromechanical gating effect in the single stranded DNA modified conical nanopores is predicted, which is due to the obstruction of the tip entrance by DNA strands oriented by the external electrical field. The magnitude of the rectification effect increases with increasing DNA length and decreasing tip diameter of the conical nanopore. The direction of on/off switching was found to be dependent on the location of the immobilized DNAs on the membrane supporting the nanopore. [source] Early signs of lethal effects in Daphnia magna (Branchiopoda, Cladocera) exposed to the insecticide cypermethrin and the fungicide azoxystrobinENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2010Ursula Friberg-Jensen Abstract This study presents the effects of sublethal concentrations of pesticides cypermethrin and azoxystrobin on the activity of several physiological parameters of egg-carrying Daphnia magna studied using a video-image technique. Single tethered daphnids were continuously recorded for 24,h of pesticide exposure, and the activity of the heart, the filtering limbs, the mandibles, and the focal spine were subsequently analyzed. Acute toxicity tests based on the criteria of immobilization were performed on egg-carrying D. magna, and sublethal concentrations of 0.1, 1.0, and 10,µg/L cypermethrin and 0.5, 1.0, and 2.0,mg/L azoxystrobin were established. At a concentration as low as 0.1,µg/L cypermethrin, the 5% effective concentration after 24,h of exposure (EC5,24h), the activity of the focal spine increased and the filtering limb activity decreased. The activity of the mandibles was reduced by exposure to 1.0 (EC18,24,h) and 10,µg/L (EC41,24,h) cypermethrin, whereas heart activity increased at a concentration of 10,µg/L (EC41,24,h). With regard to azoxystrobin, the activity of all response parameters except the focal spine decreased by exposure to 0.5,mg/L (EC4,24h) azoxystrobin. The focal spine was not affected by azoxystrobin. The results show that physiological mechanisms important for ingestion of food in D. magna may be impaired by low concentrations of commonly used pesticides. Environ. Toxicol. Chem. 2010;29:2371,2378. © 2010 SETAC [source] Single- and two-species tests to study effects of the anthelmintics ivermectin and morantel and the coccidiostatic monensin on soil invertebratesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2009John Jensen Abstract Soil invertebrates in arable land are potentially exposed to veterinary medicines excreted by husbandry. The toxicity of three widely used pharmaceuticals was therefore investigated with the use of common soil invertebrates exposed in the laboratory in single- or two-species test system. The anthelmintic morantel did not cause significant mortality to either Folsomia fimetaria or Enchytraeus crypticus even at the highest tested concentration of 900 mg kg,1 dry soil. The coccidiostatic monensin affected the reproduction of F. fimetaria and E. crypticus with soil concentrations estimated to cause a 10% effect at values of approximately 109 and 71.8 mg kg,1 dry soil, respectively, but caused no mortality to adult. The anthelmintic ivermectin did not affect the survival of adult Hypoaspis aculeifer. Reproduction of H. aculeifer declined approximately 45% in response to ivermectin exposure of 5 mg kg,1 dry soil. Ivermectin was highly toxic to F. fimetaria and affected the survival of adults with soil concentrations estimated to cause a 50% mortality at values of 5.3 mg kg,1 dry soil in the single-species test system and 0.14 mg kg,1 dry soil in the two-species test system. Reproduction of F. fimetaria was reduced by ivermectin with 10% effective concentration at 0.19 mg kg,1 dry soil in the single-species test system and 0.02 mg kg,1 dry soil in two-species test system. It was shown that species interactions may influence the response of test organisms to toxic substances. The data from this study and previously published data showed that, whereas ivermectin is likely to pose a risk to soil-dwelling invertebrates, adverse effects of morantel and monensin are unlikely to occur as a result of residue excretion from treated farm animals. [source] Evidence for vesicular glutamate transporter synapses onto gonadotropin-releasing hormone and other neurons in the rat medial preoptic areaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2003J. Kiss Abstract The medial preoptic area is a key structure in the control of reproduction. Several data suggest that excitatory amino acids are involved in the regulation of this function and the major site of this action is the medial preoptic region. Data concerning the neuromorphology of the glutamatergic innervation of the medial preoptic area are fragmentary. The present investigations were focused on: (i) the morphology of the vesicular glutamate transporter 1 (VGluT1)- and vesicular glutamate transporter 2 (VGluT2)-immunoreactive nerve terminals, which are considered to be specific to presumed glutamatergic neuronal elements, in the medial preoptic area of rat; and (ii) the relationship between these glutamate transporter-positive endings and the gonadotropin-releasing hormone (GnRH) neurons in the region. Single- and double-label immunocytochemistry was used at the light and electron microscopic level. There was a weak to moderate density of VGluT1- and a moderate to intense density of VGluT2-immunoreactive elements in the medial preoptic area. Electron microscopy revealed that both VGluT1- and VGluT2-immunoreactive boutons made asymmetric type synaptic contacts with unlabelled neurons. VGluT2-labelled, but not VGluT1-labelled, axon terminals established asymmetric synaptic contacts on GnRH-immunostained neurons, mainly on their dendrites. The present findings are the first electron microscopic examinations on the glutamatergic innervation of the rat medial preoptic area. They provide direct neuromorphological evidence for the existence of direct glutamatergic innervation of GnRH and other neurons in the rat medial preoptic area. [source] Innervation of interneurons immunoreactive for VIP by intrinsically bursting pyramidal cells and fast-spiking interneurons in infragranular layers of juvenile rat neocortexEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2002Jochen F. Staiger Abstract Cortical columns contain specific neuronal populations with characteristic sets of connections. This wiring forms the structural basis of dynamic information processing. However, at the single-cell level little is known about specific connectivity patterns. We performed experiments in infragranular layers (V and VI) of rat somatosensory cortex, to clarify further the input patterns of inhibitory interneurons immunoreactive (ir) for vasoactive intestinal polypeptide (VIP). Neurons in acute slices were electrophysiologically characterized using whole-cell recordings and filled with biocytin. This allowed us to determine their firing pattern as regular-spiking, intrinsically bursting and fast-spiking, respectively. Biocytin was revealed histochemically and VIP immunohistochemically. Sections were examined for contacts between the axons of the filled neurons and the VIP-ir targets. Twenty pyramidal cells and five nonpyramidal (inter)neurons were recovered and sufficiently stained for further analysis. Regular-spiking pyramidal cells displayed no axonal boutons in contact with VIP-ir targets. In contrast, intrinsically bursting layer V pyramidal cells showed four putative single contacts with a proximal dendrite of VIP neurons. Fast-spiking interneurons formed contacts with two to six VIP neurons, preferentially at their somata. Single as well as multiple contacts on individual target cells were found. Electron microscopic examinations showed that light-microscopically determined contacts represent sites of synaptic interactions. Our results suggest that, within infragranular local cortical circuits, (i) fast-spiking interneurons are more likely to influence VIP cells than are pyramidal cells and (ii) pyramidal cell input probably needs to be highly convergent to fire VIP target cells. [source] Competition between Non-Classical Single and Double Epimerizations in Cyclitol ChemistryEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 9 2004Ralf Miethchen Abstract Two competitive regio- and stereoselective epimerization reactions were investigated in four cyclitols characterized by four contiguous OH groups with a cis - trans - trans sequence and by varied substituents (OMe, OBz, F, H) adjacent to this tetrol unit. The starting materials were synthesized from L -quebrachitol (compounds 5,7) and myo -inositol (compound 8). Their acetalization with the chloral/DCC reagent system gave cyclic acetals with one epimerized chiral ring atom and also with two epimerized chiral centres. The single epimerization takes place exclusively at the middle C-atom of the cis - trans triol unit in the tetrol sequence (products 15, 17, 19/20 and 24,27), whereas the double epimerization occurs at both of the "centrally located" C-atoms in the cis - trans - trans tetrol unit (products 16, 18, 21 and 28). The product ratios of singly to doubly inverted compounds change as follows: the lower the electron-withdrawing effect of the substituents adjacent to the tetrol unit, the higher the percentage of the corresponding doubly inverted product. However, the singly inverted products remain the major products in all cases. X-ray analyses are given for the starting material 1-fluoro-2- O -(methyl)cyclohexane-2,3,4,5,6-pentol (5) and for the products 1- O -cyclohexylcarbamoyl-2,3- O -(2,2,2-trichloroethylidene)5- O -(methyl)cyclohexane-1,2,3,4,5-pentol (17), 3- O -acetyl-1- O -benzoyl-6- O -cyclohexylcarbamoyl-2- O -methyl-4,5- O -(2,2,2-trichloroethylidene)- muco -inositol (22) and 2,3-di- O -ethylidene)-(+/-)- chiro -inositol (24). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Single- and dual-porosity modelling of multiple tracer transport through soil columns: effects of initial moisture and mode of applicationEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2001T. Kätterer Summary We investigated the effect of initial moisture contents and mode of application on the displacement of multiple conservative tracers through undisturbed columns of a Humic Gleysol. Bromide was applied at the soil surface and chloride was injected at 5 cm depth. The columns were irrigated with deuterium-enriched water. A dual-porosity model and two single-porosity models were calibrated separately to Br, and Cl, elution curves in the two columns. Elution curves were almost identical for Br, and Cl, under initially wet conditions, whereas the displacement of Br, was faster than that of Cl, in the initially dry column, indicating rapid transport with preferential flow. Only the dual-porosity model described the long-tailing breakthrough of Cl, in the initially dry column adequately. The parameter values giving acceptable fits for ,Br dry' were not compatible with the description of the three other elution curves, which could be adequately modelled with a single set of parameter values. The estimated set of common parameters was validated by comparing with the elution curves of deuterium water, nitrate and sulphate, as well as with resident tracer concentrations at four depths. The results showed that solutes can be displaced much faster when applied at the surface of initially dry soil than when applied to wet soil or when resident in the soil matrix. The simulation results suggest that solute transport under initially dry conditions was governed by preferential flow of infiltration water through macropores by-passing the matrix due to shrinkage cracks and water repellence of matrix surfaces. [source] Trimetazidine Reduces Basal Cytosolic Ca2+ Concentration During Hypoxia in Single Xenopus Skeletal MyocytesEXPERIMENTAL PHYSIOLOGY, Issue 3 2003C. M. Stary We tested the hypotheses that: (1) Ca2+ handling and force production would be irreversibly altered in skeletal muscle during steady-state contractions when subjected to severe, prolonged hypoxia and subsequent reoxygenation; and (2) application of the cardio-protective drug trimetazidine would attenuate these alterations. Single, living skeletal muscle fibres from Xenopus laevis were injected with the Ca2+ indicator fura 2, and incubated for 1 h prior to stimulation in 100 ,M TMZ-Ringer solution (TMZ; n = 6) or standard Ringer solution (CON; n = 6). Force and relative free cytosolic Ca2+ concentration ([Ca2+]c) were measured during continuous tetanic contractions produced every 5 s as fibres were sequentially perfused in the following manner: 3 min high extracellular PO2 (159 mmHg), 15 min hypoxic perfusion (3-5 mmHg) then 3 min high PO2. Hypoxia caused a decrease in force and peak [Ca2+]c in both the TMZ and CON fibres, with no significant (P < 0.05) difference between groups. However, basal [Ca2+]c was significantly lower during hypoxia in the TMZ group vs. the CON group. While reoxygenation generated only modest recovery of relative force and peak [Ca2+]c in both groups, basal [Ca2+]c remained significantly less in the TMZ group. These results demonstrated that in contracting, single skeletal muscle fibres, TMZ prevented increases in basal [Ca2+]c generated during a severe hypoxic insult and subsequent reoxygenation, yet failed to protect the cell from the deleterious effects of prolonged hypoxia followed by reoxygenation. [source] SOA genes encode proteins controlling lipase expression in response to triacylglycerol utilization in the yeast Yarrowia lipolyticaFEMS YEAST RESEARCH, Issue 1 2010Thomas Desfougčres Abstract The oleaginous yeast Yarrowia lipolytica efficiently metabolizes hydrophobic substrates such as alkanes, fatty acids or triacylglycerol. This yeast has been identified in oil-polluted water and in lipid-rich food. The enzymes involved in lipid breakdown, for use as a carbon source, are known, but the molecular mechanisms controlling the expression of the genes encoding these enzymes are still poorly understood. The study of mRNAs obtained from cells grown on oleic acid identified a new group of genes called SOA genes (specific for oleic acid). SOA1 and SOA2 are two small genes coding for proteins with no known homologs. Single- and double-disrupted strains were constructed. Wild-type and mutant strains were grown on dextrose, oleic acid and triacylglycerols. The double mutant presents a clear phenotype consisting of a growth defect on tributyrin and triolein, but not on dextrose or oleic acid media. Lipase activity was 50-fold lower in this mutant than in the wild-type strain. The impact of SOA deletion on the expression of the main extracellular lipase gene (LIP2) was monitored using a LIP2 -,-galactosidase promoter fusion protein. These data suggest that Soa proteins are components of a molecular mechanism controlling lipase gene expression in response to extracellular triacylglycerol. [source] Synthesis and Lithium Storage Properties of Co3O4 Nanosheet-Assembled Multishelled Hollow SpheresADVANCED FUNCTIONAL MATERIALS, Issue 10 2010Xi Wang Abstract Single-, double-, and triple-shelled hollow spheres assembled by Co3O4 nanosheets are successfully synthesized through a novel method. The possible formation mechanism of these novel structures was investigated using powder X-ray diffraction, scanning and transmission electron microscopies, Fourier transform IR, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Both poly(vinylpyrrolidone) (PVP) soft templates and the formation of cobalt glycolate play key roles in the formation of these novel multishelled hollow structures. When tested as the anode material in lithium-ion batteries (LIBs), these multishelled microspheres exhibit excellent cycling performance, good rate capacity, and enhanced lithium storage capacity. This superior cyclic stability and capacity result from the synergetic effect of small diffusion lengths in the nanosheet building blocks and sufficient void space to buffer the volume expansion. This facile strategy may be extended to synthesize other transition metal oxide materials with hollow multishelled micro-/nanostrucutures, which may find application in sensors and catalysts due to their unique structural features. [source] Carbon Nanotubes: (Thermal and Structural Characterizations of Individual Single-, Double-, and Multi-Walled Carbon Nanotubes) Adv.ADVANCED FUNCTIONAL MATERIALS, Issue 24 2009Funct. Here, M. T. Pettes and L. Shi report for the first time the thermal conductance, diameter, and chiral angle for a single single-walled carbon nanotube (SWCNT). A scanning electron micrograph of the suspended micro-thermometer device and transmission electron microscopy images used to determine the SWCNT's (22, 12) chirality are shown in this frontispiece image, along with the rendered unit cell. [source] Thermal and Structural Characterizations of Individual Single-, Double-, and Multi-Walled Carbon NanotubesADVANCED FUNCTIONAL MATERIALS, Issue 24 2009Michael T. Pettes Abstract Thermal conductance measurements of individual single- (S), double- (D), and multi- (M) walled (W) carbon nanotubes (CNTs) grown using thermal chemical vapor deposition between two suspended microthermometers are reported. The crystal structure of the measured CNT samples is characterized in detail using transmission electron microscopy (TEM). The thermal conductance, diameter, and chirality are all determined on the same individual SWCNT. The thermal contact resistance per unit length is obtained as 78,585,m,K,W,1 for three as-grown 10,14,nm diameter MWCNTs on rough Pt electrodes, and decreases by more than 2 times after the deposition of amorphous platinum,carbon composites at the contacts. The obtained intrinsic thermal conductivity of approximately 42,48, 178,336, and 269,343,W,m,1,K,1 at room-temperature for the three MWCNT samples correlates well with TEM-observed defects spaced approximately 13, 20, and 29,nm apart, respectively; whereas the effective thermal conductivity is found to be limited by the thermal contact resistance to be about 600,W,m,1,K,1 at room temperature for the as-grown DWCNT and SWCNT samples without the contact deposition. [source] Single and multigrain quartz-luminescence dating of irrigation-channel features in Santa Fe, New MexicoGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 4 2009Glenn W. Berger Acequias (irrigation channels and ditches) were used by Spanish settlers, their descendants, and Native Americans in New Mexico. Several such features were recently excavated in Santa Fe, but material for numeric dating was difficult to find. Therefore, for this high-energy-deposition irrigation-feature setting we applied optically stimulated luminescence (OSL) sediment dating methods to determine the timing of last filling of some of these acequias. We report multigrain single-aliquot quartz (MGSAQ) OSL dating results and the first single-grain quartz (SGQ) OSL dating results for irrigation features. One sample yielded an average age of 96 ± 13 yr, consistent with the maximum expected age of 127 yr (before 2007). An OSL age of 175 ± 15 yr for another sample delimits a sedimentation event since the first construction of that feature ca. 300 yr ago. A sample known to be younger than 400,450 yr but predating the mid-19th century gave an SGQ age of 376 ±31 yr. These results indicate that: (1) Regional quartz in New Mexico is highly favorable to OSL dating; (2) in this setting, SGQ OSL dating is preferred to MGSAQ dating; and (3) for the last 500,600 yr, SGQ OSL dating in such settings is preferred to 14C dating because OSL dating lacks those ambiguities inherent in converting 14C ages to calendar years. © 2009 Wiley Periodicals, Inc. [source] Shaping Carbon Nanotubes and the Effects on Their Electrical and Mechanical Properties,ADVANCED FUNCTIONAL MATERIALS, Issue 11 2006S. Wang Abstract A method is developed and shown to be able to shape a carbon nanotube (CNT) into a desired morphology while maintaining its excellent electrical and mechanical properties. Single, freestanding nanotubes are bent by a scanning tunneling microscopy probe, and their morphology is fixed by electron-beam-induced deposition (inside a transmission electron microscope) of amorphous carbon on the bent area. It is shown that the mechanical strength of the bent CNT may be greatly enhanced by increasing the amount of carbon glue or the deposition area, and the electrical conduction of the nanotube shows hardly any dependence on the bending deformation or on the deposition of amorphous carbon. Our findings suggest that CNTs might be manipulated and processed as interconnections between electronic devices without much degradation in their electrical conductance, and be used in areas requiring complex morphology, such as nanometer-scale transport carriers and nanoelectromechanical systems. [source] A new strategy for studying In Vitro the drug susceptibility of clinical isolates of human hepatitis B virusHEPATOLOGY, Issue 4 2004David Durantel Resistance of hepatitis B virus (HBV) to antivirals has become a major clinical problem. Our objective was to develop a new method for the cloning of naturally occurring HBV genomes and a phenotypic assay capable of assessing HBV drug susceptibility and DNA synthesis capacity in vitro. Viral DNA was extracted from sera and was amplified by polymerase chain reaction, and amplicons were cloned into vectors that enable, after cell transfection, the initiation of the intracellular HBV replication cycle. Single or multiple clones were used to transfect Huh7 cells. The viral DNA synthesis capacity and drug susceptibility were determined by measuring the level of intracellular DNA intermediate, synthesized in absence or presence of antiviral, using Southern blot analysis. We have developed, calibrated, then used this phenotypic assay to determine the drug susceptibility of HBV quasispecies isolated throughout the course of therapy from patients selected according to their mutation profile. A multiclonal and longitudinal analysis enabled us to measure the variation of drug susceptibility of different viral quasispecies by comparison of IC50/IC90s with standards. The presence of famciclovir- or lamivudine-induced mutations in the viral population caused a change in viral DNA synthesis capacity and drug susceptibility in vitro, demonstrating the clinical relevance of the assay. In conclusion, our phenotypic assay enables the in vitro characterization of DNA synthesis capacity and drug susceptibility of HBV quasispecies isolated from patients. This assay should allow a better monitoring of patients undergoing antiviral therapy, as well as the screening of novel drugs on emerging resistant strains. (Hepatology 2004;40:855,864). [source] From grid cells to place cells: A mathematical modelHIPPOCAMPUS, Issue 12 2006Trygve Solstad Abstract Anatomical connectivity and recent neurophysiological results imply that grid cells in the medial entorhinal cortex are the principal cortical inputs to place cells in the hippocampus. The authors propose a model in which place fields of hippocampal pyramidal cells are formed by linear summation of appropriately weighted inputs from entorhinal grid cells. Single confined place fields could be formed by summing input from a modest number (10,50) of grid cells with relatively similar grid phases, diverse grid orientations, and a biologically plausible range of grid spacings. When the spatial phase variation in the grid-cell input was higher, multiple, and irregularly spaced firing fields were formed. These observations point to a number of possible constraints in the organization of functional connections between grid cells and place cells. © 2006 Wiley-Liss, Inc. [source] Organic Electro-optic Single- Crystalline Thin Films Grown Directly on Modified Amorphous Substrates,ADVANCED MATERIALS, Issue 3 2008O-P. Kwon High quality organic electro-optic single crystalline thin films are produced on amorphous C,N-modified glass substrates (see figure), which is a mimic surface of a crystal, by slow evaporation and capillary methods. The films have a suitable size (shaped as rectangular plates with side lengths in the range of 5,10 mm and regular thicknesses in the range of 1,40 ,m) for the fabrication of photonic devices. [source] DNA-Wrapped Single Walled Carbon Nanotubes as Rigid Templates for Assembling Linear Gold Nanoparticle Arrays,ADVANCED MATERIALS, Issue 11 2007X. Han Nanotube templates assembly: Water-soluble conjugates between gold nanoparticles and DNA-wrapped single-walled carbon nanotubes (SWNTs), as shown in the figure, are constructed based on a self-assembly strategy that does not require any chemical modifications to the sidewalls of the SWNTs, which minimizes the possibility of changes to their structure and properties. The success of assembling Au nanoparticles (AuNPs) onto SWNTs paves a way for further decoration of AuNPs on SWNTs to achieve multifunctionalities. [source] Intrinsic Ferroelectric Properties of Strained Tetragonal PbZr0.2Ti0.8O3 Obtained on Layer,by,Layer Grown, Defect,Free Single,Crystalline Films,ADVANCED MATERIALS, Issue 13 2006I. Vrejoiu Ferroelectric single,crystalline PbZr0.2Ti0.8O3 thin films, free from extended defects, are grown by pulsed laser deposition onto vicinal SrTiO3(001) single crystals. The PbZr0.2Ti0.8O3 films are strained and exhibit enhanced tetragonality, c/a,,,1.06. They have a remnant polarization, Pr,,,110,,C,cm,2, dielectric constant, ,33,,,90, and piezoelectric coefficient, d33, up to 50,pm,V,1 (see figure). [source] Single, twin and triple buried heating pipes: on potential savings in heat losses and costsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 14 2005Benny Bųhm Abstract In order to make district heating systems competitive in areas with single family houses or in other areas with low heat demands it is necessary to reduce the heat losses from the pipes. In recent years the twin pipe has become popular in the Nordic countries. In the article we describe how the heat loss and the heat loss coefficients can be calculated. We introduce the triple pipe with three media pipes (two supply pipes and one return pipe). The temperature dependency and the ageing of polyurethane insulation are briefly discussed. A comparison is made for different 80 mm distribution pipes and for different service pipes with respect to heat losses and to resources, i.e. materials needed for the casing and polyurethane insulation and the gravel in the excavations. For the distribution pipe we found that an egg-shaped twin pipe can reduce the heat loss by 37% and the investments by 12% compared with a pair of single pipes. For the service pipes we found that the triple pipe reduces the heat loss by 45% compared with a common pair of single pipes and by 24% compared with circular twin pipes. The reduction in investment index is 21%. The article also addresses the question of the heat exchange between the two media pipes in a twin pipe. Copyright © 2005 John Wiley & Sons, Ltd. [source] Single dose intravenous thioacetamide administration as a model of acute liver damage in ratsINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2008Tse-Min Chen Summary Thioacetamide (TAA) has been used extensively in the development of animal models of acute liver injury. Frequently, TAA is administered intraperitoneally to induce liver damage under anaesthesia. However, it is rarely administered by intravenous injection in conscious rats. The experiments in this study were designed to induce acute liver damage by single intravenous injection of TAA (0, 70 and 280 mg/kg) in unrestrained rats. Biochemical parameters and cytokines measured during the 60-h period following TAA administration, included white blood cells (WBC), haemoglobulin (Hb), platelet, aspartate transferase (GOT), alanine transferase (GPT), total bilirubin (TBIL), direct bilirubin (DBI), albumin, ammonia (NH3), r-glutamyl transpeptidase (r-GT), tumour necrosis factor-, (TNF-,) and interleukin-6 (IL-6). Rats were sacrificed by decapitation 60 h after TAA administration and livers were removed immediately for pathology and immunohistochemical (IHC) examination. Another group of rats were sacrificed by decapitation 1, 6 and 24 h after TAA administration and livers were removed immediately for time course change of pathology and IHC examination. TAA significantly increased blood WBC, GOT, GPT, TBIL, DBIL, NH3, r-GT, TNF-, and IL-6 levels but decreased the blood Hb, platelet and albumin level. The levels of histopathological damage in the liver after intravenous TAA administration were also increased with a dose-dependent trend and more increased at 60 h after TAA administration. The levels of inducible nitric oxide synthase (iNOS) and nuclear factor-,B (NF-,B) detected by IHC in the liver after intravenous TAA administration were also increased with a dose-dependent trend and more increased at 1 h after TAA administration. Single intravenous TAA administration without anaesthesia is a restorable animal model which may be used to investigate acute liver damage. [source] Ultrasonic welding of advanced thermoplastic composites: An investigation on energy-directing surfacesADVANCES IN POLYMER TECHNOLOGY, Issue 2 2010Irene Fernandez Villegas Abstract Ultrasonic welding is considered as one of the most promising welding techniques for continuous fiber-reinforced thermoplastic composites. Intermolecular friction within the bulk, resulting from the application of ultrasonic waves applied on the surfaces, generates the heat required for welding to take place at the interface of the joining members via the so-called "energy directors" (EDs). Energy directors consist of resin protrusions or artificially produced asperities on the composite surfaces and play an important role both in the welding process and in the quality of the resulting welds. This paper presents the results of a study on the effects of configuration of different EDs on the ultrasonic welding of carbon fiber/polyetherimide advanced thermoplastic composites in a near-field setup. Triangular EDs were molded on the surface of consolidated composite laminates with a hot platen press. Single lap-shear-welded samples were produced to investigate the influence of the orientation of the EDs with respect to the load direction, as well as the configuration of multiple EDs. The results indicate that the configuration of multiple transverse EDs was more effective in covering the overlap area, once the resin has melted, causing only a minimum fiber disruption at the welding interface. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:112,121, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20178 [source] Anesthesia for Heart or Single or Double Lung Transplantation in the Adult PatientJOURNAL OF CARDIAC SURGERY, Issue 3 2000Paul M. Chetham M.D. Patients with end-stage cardiac dysfunction have an impaired response to ,-agonist due to receptor downregulation. These patient will have isolated left ventricular dysfunction secondary to ischemic heart disease or present with biventricular failure with or without significant pulmonary hypertension. Increasingly, more patients have undergone prior major cardiac procedures and are at risk for significant perioperative bleeding. Patients undergoing single or double lung are particularly challenging because most of these procedures are performed without the aid of cardiopulmonary bypass. The anesthesiologist must be proficient at the management of one-lung ventilation techniques and have a rational physiologic approach to the management of intraoperative hypoxemia and auto-PEEP. [source] Role of Structural Complexities of Septal Tissue in Maintaining Ventricular Fibrillation in Isolated, Perfused Canine VentricleJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2001TAKANORI IKEDA M.D. Tissue Structure and VF.Introduction: It is unclear how the patterns of wavelet propagation during ventricular fibrillation (VF) vary between structurally different tissues. We hypothesized that the structural complexities of septal tissue influence the maintenance of reentrant wavelets in the ventricle. Methods and Results: Endocardial activation patterns during VF were analyzed in the isolated, perfused canine right ventricular (RV) free wall (n = 9), interventricular septum (n = 5), and left ventricular (LV) free wall (n = 6) using a computerized mapping system (2-mm resolution) with 120-msec consecutive windows. Each tissue sample was cut progressively to reduce the tissue mass until the VF was terminated. More wavelets were seen in the septa than in the RV and LV free walls at baseline (P = 0.004), and VF in the septa displayed a shorter cycle length than in the RV and LV free walls (P = 0.017). As the tissue mass decreased, VF became successively more organized in all regions: the number of wavelets decreased and the cycle length of VF lengthened. Single and "figure-of-eight" stationary, reentrant wavelets often were mapped after tissue mass reduction in the RV free walls and rarely in the LV free walls, but they were not observed in the septa. Less critical mass was required to maintain VF in the septa than in the RV and LV free walls (P = 0.0006). Gross anatomic and histologic examinations indicated that the tissue structure of the septa is more complex than that of the RV and LV free walls. Conclusion: VF activation patterns with progressive reduction of tissue mass differ for the septum and the ventricular free walls. The structural complexities of the septal tissue influence the maintenance of fibrillation in the ventricle. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||