PHYTOCHEMICAL ANALYSIS, Issue 5 2010
Xiao-Feng Sun
Abstract Introduction , Extraction and characterisation of hemicelluloses are very important for converting them into functional materials and chemicals. Objective , To develop a method for isolation of hemicelluloses from all cell walls. Methodology , Sequential steps using 90% dioxane, 80% acidic dioxane, 100% dimethyl sulphoxide and 8% NaOH were used for extraction of the hemicellulosic preparations (H1, H2, H3 and H4) from maize stem. Advanced NMR techniques were used for the analysis of native hemicelluloses. Results , Hemicelluloses with high yieldd were isolated from all cell walls, and contained arabinoxylan as the major polysaccharide. H3 was substituted by , - l -arabinofuranose, , - d -xylopyranose, and acetyl groups (degree of saturation = 0.12/0.09) at O -3/O -2 of xylan. H4 had a long continuous side chain of arabinose residues, and associated closely with non-cellulosic glucose. The hemicelluloses formed more linkages with guaiacyl lignins, and some p -coumaric acids built a bridge between hemicelluloses and lignin in maize stem. Conclusion , This modified method is successful for the isolation of hemicelluloses with high yields from all cell walls of maize stem. Copyright © 2010 John Wiley & Sons, Ltd. [source]

A novel organic rectorite modified bismaleimide/diallylbisphenol A system

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 11 2009
Li Yuan
Abstract 4,4,-Bismaleimidodiphenylmethane (BMIPM)/O,O,-diallylbisphenol A (BA) system was modified by organic rectorite (OREC) to develop a novel BMI/BA/OREC nanocomposite. The effect of OREC on the viscosity and reactivity of BMIPM/BA system was investigated. The mechanical properties of BMIPM/BA/OREC composites such as the flexural and impact strength were evaluated. The morphology of cured BMIPM/BA/OREC systems was investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The hot water resistance of BMIPM/BA/OREC systems was discussed. The thermal property of BMIPM/BA/OREC systems was investigated using thermogravimetric analysis (TGA). The dynamic mechanical properties of BMIPM/BA/OREC systems were also measured. Results show that the addition of OREC has a significant influence on the reactivity of the BMIPM/BA system. Proper content of OREC can improve the flexural strength, impact strength, and hot water resistance of a BMIPM/BA system. The addition of OREC cannot decrease the thermal degradation temperature of cured BMIPM/BA system with a slight sacrifice of the glass transition temperature (Tg). Copyright © 2008 John Wiley & Sons, Ltd. [source]

Numerical Analysis of the Catalytic Combustion of Premixed Methane/Air Mixtures in Microtubes

CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 9 2008
J. Zhong
Abstract The combustion characteristics and extinction limits for the catalytic combustion of a methane/air mixture in a microtube are investigated computationally using the commercial CFD code FLUENT coupled to an external subroutine DETCHEM. The effects of the microtube dimensions, conductivities of wall materials, external heat losses and flow velocity on the combustion stability, are also studied. The numerical model is set as either adiabatic or non-adiabatic with a fixed exterior heat transfer coefficient. Numerical results indicate that thermal conductivity and wall thickness are vital to preheat the methane/air mixture through the conducting wall. Two types of extinction occur, i.e., thermal quenching and blow out. These extinction limits are characterized by wall surface temperature in the microtube and the ratio of Pt(s)/O(s). [source]

Investigation of virulence genes in clinical isolates of Yersinia enterocolitica

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2008
Haoxuan Zheng
Abstract In this study, we aimed to investigate the distribution of virulence genes in clinical isolates of pathogenic Yersinia enterocolitica. Two thousand six hundred stool samples were collected from 2600 patients with diarrhea, and were tested using the culture method and real-time PCR. Then, all isolates of pathogenic Y. enterocolitica cultured from the culture method were examined for virulence genes (inv, ail, ystA, ystB, ystC, yadA, virF) by PCR and for the presence of plasmid by four phenotypic tests. As a result, 160 pathogenic strains were successfully detected by the culture method, including bio/serotype 1A/unknown (4), 1B/unknown (8), 2/O:9 (39), 2/unknown (7), 3/O:3 (22), 3/unknown (6), 4/O:3 (55), 4/unknown (10) and 5/unknown (9). The positive rate of virulence genes tested in 160 isolates was inv (100%), ail (94%), ystA (93%), ystB (7.5%), ystC (5%), yadA (89%) and virF (82%) while the phenotypic test included autoagglutination (87%), binding of crystal violet (89%), calcium-dependent growth (74%) and Congo red absorption (78%), respectively. Finally, we found that not all pathogenic Y. enterocolitica necessarily carry all traditional virulence genes in both chromosomes and plasmids to cause illness. Perhaps, some of them, lacking some traditional virulence genes, contain other unknown virulence markers that interact with each other and play an important role in the diverse pathogenesis of pathogenic Y. enterocolitica. [source]

Melatonin protects fetal rat brain against oxidative mitochondrial damage

JOURNAL OF PINEAL RESEARCH, Issue 1 2001
Akihiko Wakatsuki
Our objective was to investigate the effects of melatonin on the free radical-induced oxidative damage to mitochondria in fetal rat brain. Female Wistar rats on day 19 of pregnancy were used. Melatonin (10 mg/kg) or vehicle (control) was injected intraperitoneally 60 min prior to laparotomy for removal of the fetuses. The mitochondrial fraction was isolated from the fetal rat brain of each group. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were measured. As indicators of mitochondrial respiratory activity, we determined the respiratory control index (RCI) and the adenosine 5-diphosphate/oxygen (ADP/O) ratio in the presence and absence of 2.5 ,M hypoxanthine and 0.02 units/mL xanthine oxidase. Mitochondrial lipid peroxidation was determined by measuring the concentration of thiobarbituric acid reactive substances in fetal brain mitochondria in the presence or absence of 2.5 ,M hypoxanthine, 0.02 units/mL xanthine oxidase, and 50 ,M FeSO4. The free radical-induced rates of inhibition of mitochondrial RCI and the ADP/O ratio were both significantly lower in the fetal rat brains treated with melatonin compared with those of the controls (RCI, 44.25±15.02% vs. 25.18±5.86%, P<0.01; ADP/O ratio, 50.74±23.05% vs. 13.90±7.80%, P<0.001). The mitochondrial lipid peroxidation induced by free radicals was significantly reduced in the melatonin-treated group compared with the controls (484.2±147.2% vs. 337.6±61.0%, P<0.01). Pretreatment with melatonin significantly increased the activity of GSH-Px (20.35±5.27 to 28.93±11.01 mU/min mg,1 protein, P<0.05) in fetal rat brain mitochondria, but the activity of SOD did not change significantly. Results indicate that the administration of melatonin to the pregnant rat may prevent the free radical-induced oxidative mitochondrial damage to fetal rat brain by a direct antioxidant effect and the activation of GSH-Px. [source]

Identification of arid phases during the last 50,cal. ka BP from the Fuentillejo maar-lacustrine record (Campo de Calatrava Volcanic Field, Spain),

JOURNAL OF QUATERNARY SCIENCE, Issue 7 2010
Juana Vegas
Abstract Geochemical (element analysis, molecular analysis of organic compounds), physical, palynological, mineralogical and sedimentary facies analysis were performed to characterise the sedimentary record in Fuentillejo maar-lake in the Central Spanish Volcanic Field of Campo de Calatrava, in order to reconstruct the palaeoenvironmental and palaeoclimatic processes which controlled vegetation patterns and deposition of different sedimentary facies. The upper 20,m of core FUENT-1 show variations in clastic input, water chemistry, vegetation and organic fraction sources in the lake throughout the Late Pleistocene and Holocene. The temporal framework provided by 14C accelerator mass spectrometry dating allows assigning the sequence to the last 50,cal. ka BP. Arid phases identified in the FUENT-1 sequence are correlated to Heinrich events (HE) and to stadials of the Dansgaard/Oeschger (D/O) cycles. Siliciclastic facies with high magnetic susceptibility values, high Juniperus pollen content, a low Paq index (aquatic macrophysics proxy index), a decrease in the relative percentage of the n -C27 and an increase in the n -C31 alkanes are indicative of arid and colder climatic events related to HE 2, HE 1 and the Younger Dryas (YD). Similar short cold and arid phases during the Holocene were identified at 9.2,8.6, 7.5,7 and 5.5,5,cal. ka BP. In dolomite,mud facies, the pollen data show an increase in the herbs component, mainly , Chenopodiaceae, Artemisia and Ephedra , steppe taxa; a low Paq index, a decrease in the relative percentage of the n -C27 alkane and an increase in the n -C31 alkane are also observed. This facies was probably the result of lower lake levels and more saline,alkaline conditions, which can be interpreted as linked to arid,warm periods. These warm and arid phases were more frequent during Marine Isotope Stage (MIS) 3 and the interstadials of MIS 2. HE 4, HE 2, HE 1 and the YD in core FUENT-1 were immediately followed by increases of warm steppe pollen assemblages that document rapid warming similar to the D/O cycles but do not imply increasing humidity in the area. Fuentillejo hydrology is controlled by changes in the atmospheric and oceanic systems that operated on the North Atlantic region at millennial scale during the last 50,cal. ka BP. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Cardiovascular, general surgery, thoracic, orthopedic surgery; Dentistry/O & M

LASERS IN SURGERY AND MEDICINE, Issue S13 2001
Article first published online: 29 MAR 200
First page of article [source]

Dentistry/O & M; Dermatology/plastic surgery

LASERS IN SURGERY AND MEDICINE, Issue S13 2001
Article first published online: 29 MAR 200
First page of article [source]

Characterization of Aroma-Active Compounds in Microwave Blanched Peanuts

JOURNAL OF FOOD SCIENCE, Issue 9 2006
A.V. Schirack
ABSTRACT:, Microwave blanching of peanuts has been explored as an alternative to conventional oven methods based on its speed of operation, energy savings, and efficiency of process control. Although processing times can be greatly reduced, the occurrence of stale/floral and ashy off-flavors has been reported at high process temperatures. This study examined the chemical compounds responsible for this off-flavor using solvent extraction/solvent assisted flavor evaporation (SAFE), gas chromatography-olfactometry (GC/O), gas chromatography-mass spectrometry (GC/MS), and aroma extract dilution analysis (AEDA). Select compounds were quantified based on AEDA results using SAFE and GC/MS. Quantification, threshold testing, and analysis of model systems revealed increased formation of guaiacol and phenylacetaldehyde in the off-flavored peanuts, which resulted in the burnt and stale/floral flavors noted by a trained panel. [source]

G,, that interacts with adenylyl cyclase in opioid tolerance originates from a Gs protein

DEVELOPMENTAL NEUROBIOLOGY, Issue 12 2006
Hoau-Yan Wang
Abstract We previously demonstrated that chronic morphine induces a change in G protein coupling by the mu opioid receptor (MOR) from Gi/o to Gs, concurrent with the instatement of an interaction between G,, and adenylyl cyclase types II and IV. These two signaling changes confer excitatory effects on the cell in place of the typical inhibition by opioids and are associated with morphine tolerance and dependence. Both signaling changes and these behavioral manifestations of chronic morphine are attenuated by cotreatment with ultra-low-dose naloxone. In the present work, using striatum from chronic morphine-treated rats, we isotyped the G, within Gs and Go heterotrimers that coupled to MOR and compared these to the G, isotype of the G,, that interacted with adenylyl cyclase II or IV after chronic morphine treatment. Isotyping results show that chronic morphine causes a Gs heterotrimer associated with MOR to release its G,, to interact with adenylyl cyclase. These data suggest that the switch to Gs coupling by MOR in response to chronic morphine, which is attenuated by ultra-low-dose opioid antagonist cotreatment, leads to a two-pronged stimulation of adenylyl cyclase utilizing both G, and G,, subunits of the Gs protein novel to this receptor. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source]

AMPA receptor-mediated presynaptic inhibition at cerebellar GABAergic synapses: a characterization of molecular mechanisms

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2004
Shin'Ichiro Satake
Abstract A major subtype of glutamate receptors, AMPA receptors (AMPARs), are generally thought to mediate excitation at mammalian central synapses via the ionotropic action of ligand-gated channel opening. It has recently emerged, however, that synaptic activation of AMPARs by glutamate released from the climbing fibre input elicits not only postsynaptic excitation but also presynaptic inhibition of GABAergic transmission onto Purkinje cells in the cerebellar cortex. Although presynaptic inhibition is critical for information processing at central synapses, the molecular mechanisms by which AMPARs take part in such actions are not known. This study therefore aimed at further examining the properties of AMPAR-mediated presynaptic inhibition at GABAergic synapses in the rat cerebellum. Our data provide evidence that the climbing fibre-induced inhibition of GABA release from interneurons depends on AMPAR-mediated activation of GTP-binding proteins coupled with down-regulation of presynaptic voltage-dependent Ca2+ channels. A Gi/o -protein inhibitor, N-ethylmaleimide, selectively abolished the AMPAR-mediated presynaptic inhibition at cerebellar GABAergic synapses but did not affect AMPAR-mediated excitatory actions on Purkinje cells. Furthermore, both Gi/o -coupled receptor agonists, baclofen and DCG-IV, and the P/Q-type calcium channel blocker ,-agatoxin IVA markedly occluded the AMPAR-mediated inhibition of GABAergic transmission. Conversely, AMPAR activation inhibited action potential-triggered Ca2+ influx into individual axonal boutons of cerebellar GABAergic interneurons. By suppressing the inhibitory inputs to Purkinje cells, the AMPAR-mediated presynaptic inhibition could thus provide a feed-forward mechanism for the information flow from the cerebellar cortex. [source]

Contribution of Kir3.1, Kir3.2A and Kir3.2C subunits to native G protein-gated inwardly rectifying potassium currents in cultured hippocampal neurons

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2003
Joanne L. Leaney
Abstract G protein-gated inwardly rectifying potassium (GIRK) channels are found in neurons, atrial myocytes and neuroendocrine cells. A characteristic feature is their activation by stimulation of Gi/o -coupled receptors. In central neurons, for example, they are activated by adenosine and GABA and, as such, they play an important role in neurotransmitter-mediated regulation of membrane excitability. The channels are tetrameric assemblies of Kir3.x subunits (Kir3.1,3.4 plus splice variants). In this study I have attempted to identify the channel subunits which contribute to the native GIRK current recorded from primary cultured rat hippocampal pyramidal neurons. Reverse transcriptase,polymerase chain reaction revealed the expression of mRNA for Kir3.1, 3.2A, 3.2C and 3.3 subunits and confocal immunofluorescence microscopy was used to investigate their expression patterns. Diffuse staining was observed on both cell somata and dendrites for Kir3.1 and Kir3.2A yet that for Kir3.2C was weaker and punctate. Whole-cell patch clamp recordings were used to record GIRK currents from hippocampal pyramidal neurons which were identified on the basis of inward rectification, dependence of reversal potential on external potassium concentration and sensitivity to tertiapin. The GIRK currents were enhanced by the stimulation of a number of Gi/o -coupled receptors and were inhibited by pertussis toxin. In order to ascertain which Kir3.x subunits were responsible for the native GIRK current I compared the properties with those of the cloned Kir3.1 + 3.2A and Kir3.1 + 3.2C channels heterologously expressed in HEK293 cells. [source]

Coupling of Canine Serotonin 5-HT1B and 5-HT1D Receptor Subtypes to the Formation of Inositol Phosphates by Dual Interactions with Endogenous Gi/o and Recombinant G,15 Proteins

JOURNAL OF NEUROCHEMISTRY, Issue 3 2000
Thierry Wurch
Abstract: Molecular cloning and expression of canine (ca) serotonin 5-HT1B and ca 5-HT1D receptor subtypes showed that besides the lower binding affinity of ketanserin for the ca 5-HT1D receptor, the ligand binding profiles were similar to their human homologues. Site-directed mutagenesis studies suggest that a Gln189 residue in the second extracellular loop of the ca 5-HT1D receptor may partially account for the lower binding affinity of ketanserin. The coupling of ca 5-HT1B and ca 5-HT1D receptor subtypes to the phospholipase C pathway was analyzed by measuring stimulation of inositol phosphate formation in COS-7 cells. Zolmitriptan potently stimulated (EC50 = 4.9 nM) the inositol phosphate formation at ca 5-HT1D receptors in a fully pertussis toxin (PTX)-dependent manner, whereas only a weak PTX-resistant inositol phosphate response (26-29% at 10 ,M zolmitriptan) could be detected for the ca 5-HT1B receptor at a similar expression level. In contrast, both ca 5-HT1B and ca 5-HT1D receptor subtypes yielded a similar maximal magnitude of inositol phosphate formation (300-340% at 10 ,M zolmitriptan) upon co-expression with a mouse (m) G,15 protein. PTX treatment and co-expression with a ,-adrenergic receptor kinase C-terminal polypeptide partially (20-46%) abolished the m G,15 protein-dependent ca 5-HT1B and ca 5-HT1D receptor-mediated stimulation of inositol phosphate formation. This study suggests both 5-HT receptor subtypes can activate ,, subunits of endogenous Gi/o proteins besides their coupling to recombinant m G,15 protein. [source]

G protein-independent neuromodulatory action of adenosine on metabotropic glutamate signalling in mouse cerebellar Purkinje cells

THE JOURNAL OF PHYSIOLOGY, Issue 2 2007
Toshihide Tabata
Adenosine receptors (ARs) are G protein-coupled receptors (GPCRs) mediating the neuromodulatory actions of adenosine that influence emotional, cognitive, motor, and other functions in the central nervous system (CNS). Previous studies show complex formation between ARs and metabotropic glutamate receptors (mGluRs) in heterologous systems and close colocalization of ARs and mGluRs in several central neurons. Here we explored the possibility of intimate functional interplay between Gi/o protein-coupled A1 -subtype AR (A1R) and type-1 mGluR (mGluR1) naturally occurring in cerebellar Purkinje cells. Using a perforated-patch voltage-clamp technique, we found that both synthetic and endogenous agonists for A1R induced continuous depression of a mGluR1-coupled inward current. A1R agonists also depressed mGluR1-coupled intracellular Ca2+ mobilization monitored by fluorometry. A1R indeed mediated this depression because genetic depletion of A1R abolished it. Surprisingly, A1R agonist-induced depression persisted after blockade of Gi/o protein. The depression appeared to involve neither the cAMP-protein kinase A cascade downstream of the alpha subunits of Gi/o and Gs proteins, nor cytoplasmic Ca2+ that is suggested to be regulated by the beta-gamma subunit complex of Gi/o protein. Moreover, A1R did not appear to affect Gq protein which mediates the mGluR1-coupled responses. These findings suggest that A1R modulates mGluR1 signalling without the aid of the major G proteins. In this respect, the A1R-mediated depression of mGluR1 signalling shown here is clearly distinguished from the A1R-mediated neuronal responses described so far. These findings demonstrate a novel neuromodulatory action of adenosine in central neurons. [source]

2-{[(3-Fluorophenyl)amino]methylidene}-3-oxobutanenitrile and 5-{[(3-fluorophenyl)amino]methylidene}-2,2-dimethyl-1,3-dioxane-4,6-dione: X-ray and DFT studies

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2010
Vratislav Langer
In the crystal structures of the title compounds, C11H9FN2O, (I), and C13H12FNO4, (II), the molecules are joined pairwise via different hydrogen bonds and the constituent pairs are crosslinked by weak C,H...O hydrogen bonds. The basic structural motif in (I), which is partially disordered, comprises pairs of molecules arranged in an antiparallel fashion which enables C,H...N[triple-bond]C interactions. The pairs of molecules are crosslinked by two weak C,H...O hydrogen bonds. The constituent pair in (II) is formed by intramolecular bifurcated C,H...O/O, and combined inter- and intramolecular N,H...O hydrogen bonds. In both structures, F atoms form weak C,F...H,C interactions with the H atoms of the two neighbouring methyl groups, the H...F separations being 2.59/2.80 and 2.63/2.71,Å in (I) and (II), respectively. The bond orders in the molecules, estimated using the natural bond orbitals (NBO) formalism, correlate with the changes in bond lengths. Deviations from the ideal molecular geometry are explained by the concept of non-equivalent hybrid orbitals. The existence of possible conformers of (I) and (II) is analysed by molecular calculations at the B3LYP/6,31+G** level of theory. [source]

Pressure and gas composition effects on the operation of the pulsed flame photometric detector

ISRAEL JOURNAL OF CHEMISTRY, Issue 2 2001
Gad Frishman
The effect of pressure and hydrogen/oxygen ratio of a burning gas mixture on pulsed flame emission time-dependence was investigated in the range of 0.1,5 atm using a specially designed pulsed flame photometric detector (PFPD). We studied the pressure and gas composition effect on the pulsed flame delayed light emission of sulfur, phosphorus, and nitrogen-containing organic compounds. The optimal pressure conditions for nitrogen detection, intensity, and emission time delay was found to be 0.4 bar, at which the detection sensitivity could be improved by a factor of 2. For phosphorus, the optimal pressure obtained was 1.3 bar with 40% sensitivity improvement (compared with 1 bar). In the case of sulfur detection, two emission maxima were obtained, at 1.1 and 0.6 bar, at H/O ratio of 5. Increasing the H/O ratio resulted in the appearance of only one peak at 1 bar, and enhancement of the sensitivity by a factor of 2.4 at H/O ratio of 10.3. From the analytical point of view, we found that emission intensity is practically unchanged by the pressure and the H/O ratio for all three elements investigated in the range of 0.8,1.1 bar and H/O of 5,6. Thus, in addition to excellent sensitivity and improved selectivity, the PFPD can be applied under a variety of atmospheric pressure conditions in field environmental applications. [source]

Amperometric Sensor for Heparin: Sensing Mechanism and Application in Human Blood Plasma Analysis

ELECTROANALYSIS, Issue 13-14 2006
Jan Langmaier
Abstract Voltammetric measurements of heparin at a rotating glassy carbon (GC) electrode coated with a polyvinylchloride membrane are reported. A spin-coating technique is used to prepare thin membranes (20,40,,m) with a composition of 25% (w/w) PVC, 1,1,-dimethylferrocene as a reference electron donor for the GC|membrane interface, nitrophenyl octyl ether (o -NPOE) or bis(2-ethylhexyl) sebacate (DOS) as a plasticizer, and hexadecyltrimethylammonium tetrakis(4-chlorophenyl) borate (HTMATPBCl) or tridodecylmethylammonium tetrakis(4-chlorophenyl) borate (TDMATPBCl) as a background electrolyte. It is shown that the electrodes coated with either the HTMA+/o -NPOE (DOS) or TDMA+/o -NPOE (DOS) membrane provide a comparable amperometric response towards heparin (1,10,U mL,1) in the aqueous solution of 0.1,M LiCl. However, only the membranes formulated with TDMATPBCl can be used for an amperometric assay of heparin in human blood plasma with a detection limit of 0.2,U mL,1. Effects of membrane composition, heparin concentration, rotation speed and sweep rate on the voltammetric behavior of heparin provide some insight into the sensing mechanism. Theoretical analysis of the amperometric response is outlined, and the numeric simulation of the voltammetric behavior is presented. [source]

Recent Developments and Applications of Haptic Devices

COMPUTER GRAPHICS FORUM, Issue 2 2003
S. D. Laycock
Abstract Over recent years a variety of haptic feedback devices have been developed and are being used in a number of important applications. They range from joysticks used in the entertainment industry to specialised devices used in medical applications. This paper will describe the recent developments of these devices and show how they have been applied. It also examines how haptic feedback has been combined with visual display devices, such as virtual reality walls and workbenches, in order to improve the immersive experience. ACM CSS: H.5.2 Information Interfaces and Presentation,Haptic I/O; I.3.8 Computer Graphics,Applications; I.6 Simulation and Modelling,Applications [source]

Task-induced modulation of motor evoked potentials in upper-leg muscles during human gait: a TMS study

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2002
Mireille Bonnard
Abstract The aim of this study was to determine the relative involvement of the corticospinal (CS) pathway in voluntarily controlled walking compared to unconstrained walking. In the voluntarily controlled walking condition, subjects had to walk at the same speed as in unconstrained walking with a mechanical constraint, which is known to affect specifically the upper-leg muscles. The motor cortex was activated transcranially using a focal magnetic stimulation coil in order to elicit motor evoked potentials (MEPs) in the rectus femoris (RF) and the biceps femoris (BF). The magnetic stimulation was delivered at the end of the swing (at 90% of the cycle duration), when the EMG backgrounds were similar in the two experimental conditions. For each subject in each condition, MEPs were measured for several stimulus intensities in order to establish the input/output (I/O) curve (MEPs amplitude plotted against stimulus strength). The results showed a significant increase in the MEPs amplitude of both the RF and BF in voluntarily controlled walking compared to unconstrained walking, which is the first evidence of cofacilitation of MEPs in antagonist upper-leg muscles during human gait. In conclusion, although a lot of studies have emphasized a privileged input of the corticospinal pathway to the distal lower-leg muscles, this study shows that, if a locomotory task requires fine control of the proximal upper-leg muscles, a selective facilitation of MEPs is observed in these muscles. [source]

Indoor/outdoor concentrations and elemental composition of PM10/PM2.5 in urban/industrial areas of Kocaeli City, Turkey

INDOOR AIR, Issue 2 2010
B. Pekey
Abstract, This study presents indoor/outdoor PM2.5 and PM10 concentrations measured during winter and summer in 15 homes in Kocaeli, which is one of the most industrialized areas in Turkey. Indoor and outdoor PM2.5 and PM10 mass concentrations and elemental composition were determined using an X-ray fluorescence spectrometer. Quantitative information was obtained on mass concentrations and other characteristics such as seasonal variation, indoor/outdoor (I/O) ratio, PM2.5/PM10 ratio, correlations and sources. Average indoor and outdoor PM2.5 concentrations were 29.8 and 23.5 ,g/m3 for the summer period, and 24.4 and 21.8 ,g/m3 for the winter period, respectively. Average indoor and outdoor PM10 concentrations were 45.5 and 59.9 ,g/m3 for the summer period, and 56.9 and 102.3 ,g/m3 for the winter period, respectively. A varimax rotated factor analysis (FA) was performed separately on indoor and outdoor datasets in an effort to identify possible heavy metal sources of PM2.5 and PM10 particle fractions. FA of outdoor data produced source categories comprising polluted soil, industry, motor vehicles, and fossil fuel combustion for both PM fractions, while source categories determined for indoor data for both PM2.5 and PM10 comprised industry, polluted soil, motor vehicles, and smoking, with an additional source category of cooking activities detected for the PM2.5 fraction. Practical Implications In buildings close to industrial areas or traffic arteries, outdoor sources may have an important effect on indoor air pollution. Therefore, indoor and outdoor investigations should be conducted simultaneously to assess the relationship between indoor and outdoor pollution. This study presents the simultaneous measurement of PM fractions (PM2.5 and PM10) and their elemental compositions to determine the sources of respirable PM and the heavy metals bound to these particles in indoor air. Factor analysis of indoor data indicated that the contribution of outdoor pollutant sources to indoor pollution was about 70%, making these sources the most significant for indoor heavy metal pollution, wheras other sources of indoor pollution included smoking and cooking activities. [source]

ACE4k: An analog I/O 64×64 visual microprocessor chip with 7-bit analog accuracy

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 2-3 2002
G. Liñán
Abstract This paper describes a full-custom mixed-signal chip which embeds distributed optical signal acquisition, digitally-programmable analog parallel processing, and distributed image memory cache on a common silicon substrate. This chip, designed in a 0.5 µm standard CMOS technology contains around 1.000.000 transistors, of which operate in analog mode; it is hence one the most complex mixed-signal chip reported to now. Chip functional features are: local interactions, spatial-invariant array architecture; programmable local interactions among cells; randomly-selectable memory of instructions (elementary instructions are defined by specific values of the cell local interactions); random storage/retrieval of intermediate images; capability to complete algorithmic image processing tasks controlled by the user-selected stored instructions and interacting with the cache memory, etc. Thus, as illustrated in this paper, the chip is capable to complete complex spatio-temporal image processing tasks within short computation time (<300 ns for linear convolutions) and using a low power budget (<1.2 W for the complete chip). The internal circuitry of the chip has been designed to operate in robust manner with >7-bits equivalent accuracy in the internal analog operations, which has been confirmed by experimental measurements. Such 7-bits accuracy is enough for most image processing applications. ACE4k has been demonstrated capable to implement up to 30 template,-either directly or through template decomposition. This means the 100% of the 3×3 linear templates reported in Roska et al. 1998, [1]. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Robust nonlinear ship course-keeping control by H, I/O linearization and , -synthesis

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 1 2003
Shr-Shiung Hu
Abstract In this paper, the H, input/output (I/O) linearization formulation is applied to design an inner-loop nonlinear controller for a nonlinear ship course-keeping control problem. Due to the ship motion dynamics are non-minimum phase, it is impossible to use the ordinary feedback I/O linearization to resolve. Hence, the technique of H, I/O linearization is proposed to obtain a nonlinear H, controller such that the compensated nonlinear system approximates the linear reference model in I/O behaviour. Then a , -synthesis method is employed to design an outer-loop robust controller to address tracking, regulation, and robustness issues. The time responses of the tracking signals for the closed-loop system reveal that the overall robust nonlinear controller is able to provide robust stability and robust performance for the plant uncertainties and state measurement errors. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Novel dual-mode DC-block triangular-patch bandpass filter

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2007
Ming Li
Abstract A novel dual-mode DC-block bandpass filter (BPF) using a pair of V-shape slots on triangular-patch resonators is developed in this letter. The V-shape slots perturb the field distributions of triangular-patch resonators and excite degenerate modes. Compared to our previous research, the length of input/output (I/O) lines of the proposed filter is reduced so that the circuit becomes compact. Finally, the good agreement between the simulated and measured results of the proposed BPF is presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1648,1649, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22520 [source]

Low-loss triangular-patch dual-mode bandpass filter with slotted input/output

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2007
Haiwen Liu
Abstract Without any perturbations on the surface of the patch resonator or orthogonal feed lines, a novel microstrip dual-mode triangular-patch bandpass filter with slotted I/O is introduced in this letter. The degenerate modes are excited by the use of the slotted I/O. Also, the coupling characteristics of two degenerate modes are studied with respect to main design parameters. A dual-mode filter with 0.8 dB insertion loss in the passband was designed and fabricated. Measurement verify the validity of the proposed design method. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 147,149, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22072 [source]

Investigation into microstrip dual-mode bandpass filters (BPFS) with in-line feed-line configurations

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2006
JiaLin Li
Abstract Based on the geometry relationship of the conventional dual-mode ring resonators, this study concisely describes the operation principle of a kind of dual-mode resonator filters with in-line feed-lines. The investigated filter topology is fed by two pairs of orthogonal branch lines and can realize in-line configuration for the input and output (I/O) ports, which is useful in many practical applications. Meanwhile, the influences of feed-lines on transmission-zeros (TZs) are, for the first time, investigated to guide the design of this kind of filters. Several demonstrators are designed and examined, and good results are obtained. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2008,2013, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21845 [source]

New design concept of dual-mode bandpass filter by using nonorthogonal input and output ports for wireless application

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2006
Han-Jan Chen
Abstract In this paper, new design concept of nonorthogonal input and output (I/O) ports applied to optimize dual-mode bandpass ring filter is proposed. Compared to conventional dual-mode filters, the proposed filter with nonorthogonal I/O could not only support two degenerate modes operation, but also increase design flexibility. Moreover, the design of dual-mode filters would not have an I/O geometry limitation, corresponding to high integration. Finally, a simple structure and high selectivity for the dual-mode bandpass filters were obtained. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 639,641, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21431 [source]

Bipolariton laser emission from a GaAs microcavity

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2007
L. M. Moreira
Abstract Biexciton emission properties were studied in a single GaAs quantum well (QW) semiconductor planar microcavity by photoluminescence measurements at low temperatures. At high pump intensity a bipolariton emission appears close to the lower polariton mode. This new mode appears when we detune the cavity resonance out of the lower polariton branch, showing a laser like behavior. Very small linewidths were measured, lying below 110 µeV and 150 µeV for polariton and bipolariton emission respectively. The input/output power (I/O) measurements show that the bipolariton emission has a weaker coupling efficiency compared to previous results for polariton emission. Varying the pump laser polarization, we were able to show the selection rules for the biexciton particle creation in the quantum well. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Improving the quality of industry and occupation data at a central cancer registry

AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 10 2010
Karla R. Armenti ScD
Abstract Background Central cancer registries are required to collect industry and occupation (I/O) information when available, but the data reported are often incomplete. Methods We audited the completeness of I/O data in the New Hampshire State Cancer Registry (NHSCR) database for diagnosis year 2005, and reviewed medical records for a convenience sample of 474 of these cases. We compared I/O data quality before and after a statewide registrar training session on occupationally related cancers. Results The original 2005 data contained both I/O data in 11.5% of cases, and lacked any I/O data in 74.5%. Corresponding figures for cases selected for audit were 15.2% and 77.2%, which improved to 54.2% and 11.8% after medical record review. After registrar training, 47% of reports contained both I/O data, and only 14.4% of cases lacked any I/O data. Conclusions Statewide training to highlight the importance of I/O data is an effective method to improve I/O data quality. Am. J. Ind. Med. 53:995,1001, 2010. © 2010 Wiley-Liss, Inc. [source]

Self-Regulation Research in Work and I/O Psychology

APPLIED PSYCHOLOGY, Issue 2 2005
Ruth Kanfer
Les recherches de psychologie industrielle/organisationnelle (I/O) sur les objectifs et l'autorégulation ont prospéré durant les trois dernières décennies. Initiés par le travail fécond de Locke, Latham et de leurs collègues qui ont souligné l'influence positive d'objectifs elairs et sollicitants sur les performances, de nombreux courants de recherche sont apparus pour étudier à la fois les déterminants et les conséquences des objectifs et des processus d'autorégulation sur les conduites et les variables dépendantes relatives au travail (voir par exemple Locke, Shaw, Saari, & Latham, 1981; Vancouver, 2000 pour une revue de questions). Vancouver et Day (2005) constatent que si les chercheurs en organisations ont tenté d'évaluer la validité externe et critérielle, ils se sont moins intéressés à la validité interne et de construction des variables-clés et de concepts tels que les objectifs, la rétroaction, la divergence et l'efficacité personnelle. Dans le même ordre d'idées, Vancouver et Day (2004) concluent que les validations des interventions I/O fondées sur la perspective objectif/autorégulation détectent généralement des effcts positifs, mais que ces travaux sont insuffisants pour déterminer les dimensions spécifiques du processus objectif/autorégulation qui sont en rapport avec l'amélioration de la performance. Dans ce court article, j'aborde ces problèmes concemant la recherche sur les objectifs et l'autorégulation d'un triple point de vue: le progrès scientifique, les applications et les buts des investigations I/O. Over the past three decades, industrial/organisational (I/O) research on goals and self-regulation has flourished. Beginning with the seminal work by Locke, Latham, and their colleagues showing the positive influence of difficult and specific goals on task performance, multiple streams of research have emerged to investigate both the determinants and consequences of goals and self-regulation processes on work-related behaviors and outcomes (see, e.g. Locke, Shaw, Saari, & Latham, 1981; Vancouver, 2000, for reviews). In a review of this work, Vancouver and Day (2005) suggest that although organisational researchers have sought evidence for external and criterion-related validity, less attention has been given to the construct and internal validity of key variables and concepts, such as goals, self-efficacy, feedback, discrepancy, and self-efficacy. In a related vein, Vancouver and Day (2005) conclude that although I/O intervention studies based on the goal/self-regulation perspective show generally positive effects, such studies are insufficient for understanding how specific aspects of the goal/self-regulation process relate to enhanced performance. In this short note, I consider these concerns about goal/self-regulation research in I/O psychology from three perspectives: (1) scientific progress, (2) applications, and (3) the goals of I/O research. [source]

Synthesis of Enantiomerically Pure 2,3,4,6-Tetrasubstituted Tetrahydropyrans by Prins-Type Cyclization of Methyl Ricinoleate and Aldehydes,

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 11 2006
Ursula Biermann
Abstract The AlCl3 -catalyzed Prins-type cyclization of methyl ricinoleate (1), an enantiomerically pure renewable compound, with aldehydes such as heptanal (2a), isobutyraldehyde (2b), pivaldehyde (2c) and benzaldehyde (2d) is a simple reaction for the diastereoselective synthesis of enantiomerically pure 2,3,6-trialkyl-substituted 4-chlorotetrahydropyrans. The respective 4-hydroxytetrahydropyrans are obtained e.g. with aldehydes 2a and 2d using montmorillonite KSF/O as the catalyst. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]