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Selected AbstractsBismuth Film Electrode as an Alternative for Mercury Electrodes: Determination of Azo Dyes and Application for Detection in Food StuffsELECTROANALYSIS, Issue 21 2007Benoît Claux Abstract Bismuth electrodes were investigated and exhibit electrochemical properties similar to mercury electrodes but with much lower toxicity. An electrochemical application of bismuth film modified glassy carbon electrode for azo dyes determination was investigated. The plating step was optimized in order to achieve its analytical efficiency. A plating potential of ,0.9,V in a solution of 200,mg/L Bi(NO3)3, 0.5,M HNO3 for 100,s yields to a suitable electrode (in terms of stability and detection). Azo dyes such as azorubine (i.e., carmoisine, E122), amaranth (E123), ponceau 4R (i.e., new coccine, E124) and allura red (E129) were determined by differential pulse voltammetry in a NaCl solution in the concentration range of few ppm to 100 ppm. The reproducibility of the signal, characterized by the relative standard deviation, was found to be less than 5%, the detection and quantification limits were few mg/L. The influence of other food components on the signal was studied and the applicability was tested on real beverages samples. [source] Storage stability study of margarines produced from enzymatically interesterified fats compared to margarines produced by conventional methods.EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 7-8 2005Physical properties Abstract In this study, margarine hardstocks were produced from two enzymatically interesterified fats at conversion degrees of 80 and 100%, a chemically randomized fat and a physically mixed fat, respectively. These four hardstocks blended with 50% of sunflower oil were mainly used for the production of table margarines in a pilot plant. Storage stability studies were carried out at storage temperatures of 5 and 25,°C during 12,wk. Margarines from the enzymatically interesterified fats were compared to the margarines produced by conventional methods and to selected commercial products. The changes in the physical properties of margarines, including hardness, dropping point, crystal form, and sensory evaluation, were examined during storage. It was observed that margarine storage stability increased with increasing conversion degree. The color of margarines made from the enzymatically interesterified fats was more similar to that of the physically mixed fat than that of the margarine from the chemically randomized fat, which had less color. Crystal transformation was accelerated at high storage temperature. Crystal size was not only related to the types of crystals, but also to the driving force of temperature difference. A larger crystal size was observed at 5,°C than at 25,°C for the margarine made from the blend. Margarines produced from interesterified fats had better physical properties than the blend. Overall, the margarine produced from the enzymatically fully converted fat had physical properties similar to the margarine produced from the chemically interesterified fat. [source] The organization of visual object representations: a connectionist model of effects of lesions in perirhinal cortexEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2002Timothy J. Bussey Abstract We have developed a simple connectionist model based on the idea that perirhinal cortex has properties similar to other regions in the ventral visual stream, or ,what' pathway. The model is based on the assumption that representations in the ventral visual stream are organized hierarchically, such that representations of simple features of objects are stored in caudal regions of the ventral visual stream, and representations of the conjunctions of these features are stored in more rostral regions. We propose that a function of these feature conjunction representations is to help to resolve ,feature ambiguity', a property of visual discrimination problems that can emerge when features of an object predict a given outcome (e.g. reward) when part of one object, but predict a different outcome when part of another object. Several recently reported effects of lesions of perirhinal cortex in monkeys have provided key insights into the functions of this region. In the present study these effects were simulated by comparing the performance of connectionist networks before and after removal of a layer of units corresponding to perirhinal cortex. The results of these simulations suggest that effects of lesions in perirhinal cortex on visual discrimination may be due not to the impairment of a specific type of learning or memory, such as declarative or procedural, but to compromising the representations of visual stimuli. Furthermore, we propose that attempting to classify perirhinal cortex function as either ,perceptual' or ,mnemonic' may be misguided, as it seems unlikely that these broad constructs will map neatly onto anatomically defined regions of the brain. [source] Homeostatic plasticity induced by chronic block of AMPA/kainate receptors modulates the generation of rhythmic bursting in rat spinal cord organotypic culturesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2001Micaela Galante Abstract Generation of spontaneous rhythmic activity is a distinct feature of developing spinal networks. We report that rat embryo organotypic spinal cultures contain the basic circuits responsible for pattern generation. In this preparation rhythmic activity can be recorded from ventral interneurons and is developmentally regulated. When chronically grown in the presence of an AMPA/kainate receptor blocker, this circuit expresses long-term plasticity consisting largely of increased frequency of fast synaptic activity and reduction in slow GABAergic events. We examined whether, once this form of homeostatic plasticity is established, the network could still exhibit rhythmicity with properties similar to controls. Control or chronically treated ventral interneurons spontaneously generated (with similar probability) irregular, network-driven bursts over a background of ongoing synaptic activity. In control cultures increasing network excitability by strychnine plus bicuculline, or by raising [K+]o, induced rapid-onset, regular rhythmic bursts. In treated cultures the same pharmacological block of Cl, -mediated transmission or high-K+ application also induced regular patterned activity, although significantly faster and, in the case of high K+, characterized by slow onset due to postsynaptic current summation. Enhancing GABAergic transmission by pentobarbital surprisingly accelerated the high-K+ rhythm of control cells (though depressing background activity), whereas it slowed it down in chronically treated cells. This contrasting effect of pentobarbital suggests that, to preserve bursting ability, chronic slices developed a distinct GABAergic inhibitory control on over-expressed bursting circuits. Conversely, in control slices GABAergic transmission depressed spontaneous activity but it facilitated bursting frequency. Thus, even after homeostatic rearrangement, developing mammalian spinal networks still generate rhythmic activity. [source] Mutagenic probes of the role of Ser209 on the cavity shaping loop of human monoamine oxidase AFEBS JOURNAL, Issue 16 2009Jin Wang The available literature implicating human monoamine oxidase A (MAO A) in apoptotic processes reports levels of MAO A protein that do not correlate with activity, suggesting that unknown mechanisms may be involved in the regulation of catalytic function. Bioinformatic analysis suggests Ser209 as a possible phosphorylation site that may be relevant to catalytic function because it is adjacent to a six-residue loop termed the ,cavity shaping loop' from structural data. To probe the functional role of this site, MAO A Ser209Ala and Ser209Glu mutants were created and investigated. In its membrane-bound form, the MAO A Ser209Glu phosphorylation mimic exhibits catalytic and inhibitor binding properties similar to those of wild-type MAO A. Solubilization in detergent solution and purification of the Ser209Glu mutant results in considerable decreases in these functional parameters. By contrast, the MAO A Ser209Ala mutant exhibits similar catalytic properties to those of wild-type enzyme when purified. Compared to purified wild-type and Ser209Ala MAO A proteins, the Ser209Glu MAO A mutant shows significant differences in covalent flavin fluorescence yield, CD spectra and thermal stability. These structural differences in the purified MAO A Ser209Glu mutant are not exhibited in quantitative structure,activity relationship patterns using a series of para -substituted benzylamine analogs similar to the wild-type enzyme. These data suggest that Ser209 in MAO A does not appear to be the putative phosphorylation site for regulation of MAO A activity and demonstrate that the membrane environment plays a significant role in stabilizing the structure of MAO A and its mutant forms. [source] Putative reaction mechanism of heterologously expressed octopine dehydrogenase from the great scallop, Pecten maximus (L)FEBS JOURNAL, Issue 24 2007Andre Müller cDNA for octopine dehydrogenase (ODH) from the adductor muscle of the great scallop, Pecten maximus, was cloned using 5,- and 3,-RACE. The cDNA comprises an ORF of 1197 nucleotides and the deduced amino acid sequence encodes a protein of 399 amino acids. ODH was heterologously expressed in Escherichia coli with a C-terminal penta His-tag. ODH,5His was purified to homogeneity using metal,chelate affinity chromatography and Sephadex G-100 gel filtration. Recombinant ODH had kinetic properties similar to those of wild-type ODH isolated from the scallop's adductor muscle. Site-directed mutagenesis was used to elucidate the involvement of several amino acid residues for the reaction catalyzed by ODH. Cys148, which is conserved in all opine dehydrogenases known to date, was converted to serine or alanine, showing that this residue is not intrinsically important for catalysis. His212, Arg324 and Asp329, which are also conserved in all known opine dehydrogenase sequences, were subjected to site-directed mutagenesis. Modification of these residues revealed their importance for the catalytic activity of the enzyme. Conversion of each of these residues to alanine resulted in strong increases in Km and decreases in kcat values for pyruvate and l -arginine, but had little effect on the Km and kcat values for NADH. Assuming a similar structure for ODH compared with the only available structure of a bacterial opine dehydrogenase, these three amino acids may function as a catalytic triad in ODH similar to that found in lactate dehydrogenase or malate dehydrogenase. The carboxyl group of pyruvate is then stabilized by Arg324. In addition to orienting the substrate, His212 will act as an acid,base catalyst by donating a proton to the carbonyl group of pyruvate. The acidity of this histidine is further increased by the proximity of Asp329. [source] CK2,tes gene encodes a testis-specific isoform of the regulatory subunit of casein kinase 2 in Drosophila melanogasterFEBS JOURNAL, Issue 5 2002Alla I. Kalmykova An earlier described CK2,tes gene of Drosophila melanogaster is shown to encode a male germline specific isoform of regulatory ,,subunit of casein kinase 2. Western-analysis using anti-CK2,tes Ig revealed CK2,tes protein in Drosophila testes extract. Expression of a CK2,tes,,-galactosidase fusion protein driven by the CK2,tes promoter was found in transgenic flies at postmitotic stages of spermatogenesis. Examination of biochemical characteristics of a recombinant CK2,tes protein expressed in Escherichia coli revealed properties similar to those of CK2,: (a) CK2,tes protein stimulates CK2, catalytic activity toward synthetic peptide; (b) it inhibits phosphorylation of calmodulin and mediates stimulation of CK2, by polylysine; (c) it is able to form (CK2,tes)2 dimers, as well as (CK2,)2(CK2,tes)2 tetramers. Using the yeast two-hybrid system and coimmunoprecipitation analysis of protein extract from Drosophila testes, we demonstrated an association between CK2,tes and CK2,. Northern-analysis has shown that another regulatory (,,) subunit found recently in D. melanogaster genome is also testis-specific. Thus, we describe the first example of two tissue-specific regulatory subunits of CK2 which might serve to provide CK2 substrate recognition during spermatogenesis. [source] Engineering of a monomeric and low-glycosylated form of human butyrylcholinesteraseFEBS JOURNAL, Issue 2 2002Expression, characterization, crystallization, purification Human butyrylcholinesterase (BChE; EC 3.1.1.8) is of particular interest because it hydrolyzes or scavenges a wide range of toxic compounds including cocaine, organophosphorus pesticides and nerve agents. The relative contribution of each N-linked glycan for the solubility, the stability and the secretion of the enzyme was investigated. A recombinant monomeric BChE lacking four out of nine N-glycosylation sites and the C-terminal oligomerization domain was stably expressed as a monomer in CHO cells. The purified recombinant BChE showed catalytic properties similar to those of the native enzyme. Tetragonal crystals suitable for X-ray crystallography studies were obtained; they were improved by recrystallization and found to diffract to 2.0 Å resolution using synchrotron radiation. The crystals belong to the tetragonal space group I422 with unit cell dimensions a = b = 154.7 Å, c = 124.9 Å, giving a Vm of 2.73 Å3 per Da (estimated 60% solvent) for a single molecule of recombinant BChE in the asymmetric unit. The crystal structure of butyrylcholinesterase will help elucidate unsolved issues concerning cholinesterase mechanisms in general. [source] Heterologous gene expression in Lactococcus lactis; expression of the Azotobacter vinelandii algE6 gene product displaying mannuronan C-5 epimerase activityFEMS MICROBIOLOGY LETTERS, Issue 2 2003Janet M. Blatny Abstract The Azotobacter vinelandii mannuronan C-5 epimerases AlgE1,7 can be used to improve the properties of the commercially important polysaccharide alginate that is widely used in a variety of products, such as food and pharmaceuticals. Since lactic acid bacteria are generally regarded as safe, they are attractive candidates for production of the epimerases. A. vinelandii genes are GC-rich, in contrast to those of lactic acid bacteria, but we show here that significant expression levels of the epimerase AlgE6 can be obtained in Lactococcus lactis using the nisin-controlled expression system. A 1200-fold induction ratio was obtained resulting in an epimerase activity of 23,900 dpm mg,1 h,1, using a tritiated alginate substrate. The epimerase was detected by Western blotting and nuclear magnetic resonance spectroscopy analysis of its reaction product showed that the enzyme displayed catalytic properties similar to those produced in Escherichia coli. [source] Climatic controls on the carbon and water balances of a boreal aspen forest, 1994,2003GLOBAL CHANGE BIOLOGY, Issue 3 2007ALAN G. BARR Abstract The carbon and water budgets of boreal and temperate broadleaf forests are sensitive to interannual climatic variability and are likely to respond to climate change. This study analyses 9 years of eddy-covariance data from the Boreal Ecosystem Research and Monitoring Sites (BERMS) Southern Old Aspen site in central Saskatchewan, Canada and characterizes the primary climatic controls on evapotranspiration, net ecosystem production (FNEP), gross ecosystem photosynthesis (P) and ecosystem respiration (R). The study period was dominated by two climatic extremes: extreme warm and cool springs, which produced marked contrasts in the canopy duration, and a severe, 3-year drought. Annual FNEP varied among years from 55 to 367 g C m,2 (mean 172, SD 94). Interannual variability in FNEP was controlled primarily by factors that affected the R/P ratio, which varied between 0.74 and 0.96 (mean 0.87, SD 0.06). Canopy duration enhanced P and FNEP with no apparent effect on R. The fraction of annual photosynthetically active radiation (PAR) that was absorbed by the canopy foliage varied from 38% in late leaf-emergence years to 51% in early leaf-emergence years. Photosynthetic light-use efficiency (mean 0.0275, SD 0.026 mol C mol,1 photons) was relatively constant during nondrought years but declined with drought intensity to a minimum of 0.0228 mol C mol,1 photons during the most severe drought year. The impact of drought on FNEP varied with drought intensity. Years of mild-to-moderate drought suppressed R while having little effect on P, so that FNEP was enhanced. Years of severe drought suppressed both R and P, causing either little change or a subtle reduction in FNEP. The analysis produced new insights into the dominance of canopy duration as the most important biophysical control on FNEP. The results suggested a simple conceptual model for annual FNEP in boreal deciduous forests. When water is not limiting, annual P is controlled by canopy duration via its influence on absorbed PAR at constant light-use efficiency. Water stress suppresses P, by reducing light-use efficiency, and R, by limiting growth and/or suppressing microbial respiration. The high photosynthetic light-use efficiency showed this site to be a highly productive boreal deciduous forest, with properties similar to many temperate deciduous forests. [source] Parallel asynchronous variational integratorsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 3 2007Kedar G. Kale Abstract This paper presents a scalable parallel variational time integration algorithm for nonlinear elastodynamics with the distinguishing feature of allowing each element in the mesh to have a possibly different time step. Furthermore, the algorithm is obtained from a discrete variational principle, and hence it is termed parallel asynchronous variational integrator (PAVI). The underlying variational structure grants it outstanding conservation properties. Based on a domain decomposition strategy, PAVI combines a careful scheduling of computations with fully asynchronous communications to provide a very efficient methodology for finite element models with even mild distributions of time step sizes. Numerical tests are shown to illustrate PAVI's performance on both slow and fast networks, showing scalability properties similar to the best parallel explicit synchronous algorithms, with lower execution time. Finally, a numerical example in which PAVI needs ,100 times less computing than an explicit synchronous algorithm is shown. Copyright © 2006 John Wiley & Sons, Ltd. [source] Microstructural Characterization and Mechanical Properties of Si3N4 Formed by Fused Deposition of CeramicsINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 2 2008S. Iyer We present processing (green and sintered), part shrinkage and warping, microstructural characterization, and mechanical properties of Si3N4 made by fused deposition of ceramics (FDC), using optical microscopy, scanning electron microscopy, and X-ray diffraction. The mechanical properties (fracture strength, fracture toughness, and Weibull modulus) are also reported. Proper FDC build parameters resulted in dense, homogeneous, near-net-shape Si3N4, with microstructures and mechanical properties similar to conventionally processed material. Mechanical properties are shown to be isotropic, while there is some degree of microstructural texturing (preferred ,-Si3N4 grain orientation) in sintered components. [source] Development of a healthy low-fat fish sausage containing dietary fibreINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2008Carlos Cardoso Summary In order to develop a healthy low-fat fish sausage containing dietary fibre (DF), three fundamental changes were made to an ordinary pork sausage recipe: incorporation of 4% (w/w) of Swelite® (a DF obtained from inner pea), different levels of pork meat replacement (0%, 50% and 100%) by hake mince and the combination of varying amounts of Fibruline® (a DF obtained from chicory root) and hake mince (Fibruline: additional hake mince, 2.6:5.2, 5.2:2.6 and 7.8:0.0, % w/w) as a substitute for pork fat. It was found that the addition of Swelite to pork sausage favoured greater gel strength and hardness. On the contrary, increasing levels of pork meat replacement by hake reduced the sausages' gel strength and hardness. Finally, sausages without pork fat showed promising textural and colour parameters. High-Fibruline sausages were less cohesive and chewable than pork fat sausages (control), but also exhibited a greater gel strength. Low-Fibruline ones presented almost all textural properties similar to the control, with exception of hardness and gumminess. Therefore, regarding some key textural parameters, it was possible to produce low-fat fish sausages similar to the ordinary pork sausages. [source] Cellulose as a renewable resource for the synthesis of wood consolidantsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Giacomo Cipriani Abstract Crosslinkable cellulose ethers as allyl cellulose, allyl carboxymethyl cellulose, and allyl n -hydroxypropyl cellulose were synthesized and characterized, and their use as consolidating agents for waterlogged wood was studied. For this kind of application, structural properties similar to those of wood's polysaccharide components are desired in the design stage of new consolidants. The choice to synthesize cellulose ethers was determined from the possibility of using cellulose as the starting material because of its large availability in nature, biocompatibility, and low cost. In addition, cellulose ethers are quite easy to obtain, and they can have different properties, depending on the nature and the amount of the functional groups introduced. For this purpose, a cellulose with a lower degree of polymerization was also used for the synthesis of related cellulose ethers. By means of Fourier transform infrared spectroscopy, the affinity of the cellulose derivatives for degraded lignin flours was detected. The preliminary results of this study show that these polysaccharide compounds may be proposed as wood consolidating agents. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Efficient assessment of social problem-solving abilities in medical and rehabilitation settings: a rasch analysis of the social problem-solving inventory-revisedJOURNAL OF CLINICAL PSYCHOLOGY, Issue 7 2009Laura E. Dreer Abstract The Social Problem Solving Inventory-Revised Scale (SPSI-R) has been shown to be a reliable and valid self-report measure of social problem-solving abilities. In busy medical and rehabilitation settings, a brief and efficient screening version with psychometric properties similar to the SPSI-R would have numerous benefits including decreased patient and caregiver assessment burden and administration/scoring time. Thus, the aim of the current study was to identify items from the SPSI-R that would provide for a more efficient assessment of global social problem-solving abilities. This study consisted of three independent samples: 121 persons in low-vision rehabilitation (M age=71 years old, SD=15.53), 301 persons living with diabetes mellitus (M age=58, and SD=14.85), and 131 family caregivers of persons with severe disabilities (M age=56 years old, SD=12.15). All persons completed a version of the SPSI-R, Center for Epidemiological Studies Depression Scale (CES-D), and the Satisfaction with Life Scale (SWLS). Using Rasch scaling of the SPSI-R short-form, we identified a subset of 10 items that reflected the five-component model of social problem solving. The 10 items were separately validated on the sample of persons living with diabetes mellitus and the sample of family caregivers of persons with severe disabilities. Results indicate that the efficient 10-item version, analyzed separately for all three samples, demonstrated good reliability and validity characteristics similar to the established SPSI-R short form. The 10-item version of the SPSI-R represents a brief, effective way in which clinicians and researchers in busy health care settings can quickly assess global problem-solving abilities and identify those persons at-risk for complicated adjustment. Implications for the assessment of social problem-solving abilities are discussed. © 2009 Wiley Periodicals, Inc. J Clin Psychol 65: 1,15, 2009. [source] AN ESTEROLYTIC ACTIVITY FROM A WILD EDIBLE MUSHROOM, LYCOPERDON PERLATUMJOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2009AHMET COLAK ABSTRACT Lycoperdon perlatum Pers. (Lycoperdaceae, Agaricales, Agaricomycetidae, Agaricomycetes, Basidiomycota, Fungi) was evaluated for its esterolytic potential. Native electrophoresis of the crude extracts showed four bands having Rf values of 0.34, 0.39, 0.52 and 0.59. The esterase showed the highest activity toward a short-chain substrate, p -nitrophenyl acetate. Optimum reaction conditions for L. perlatum crude extract were attained at pH 8.0 and 40C. Esterolytic activity of enzyme extract was stimulated in the presence of Mn2+, Fe2+, Ca2+ and Zn2+ in the reaction mixture. The enzyme activity was stimulated by incubation at pH 6.0 but retained 77% of its original activity at its optimum pH after 24 h. Thermal inactivation was displayed after incubation for 20 min at various temperatures above 30C. At 1 mM final concentration, 2-mercaptoethanol, dithiothreitol, ethylenediamine tetraacetic acid and p -methylphenyl sulfonylfluoride inhibited the esterolytic reaction. These results support that the crude L. perlatum extract possesses an esterolytic activity having properties similar to other esterases. PRACTICAL APPLICATIONS Esterases catalyzing the cleavage and formation of ester bonds are known ,/,-hydrolases (EC 3.1.1.X). Esterases are used for the synthesis of flavor esters for the food industry, modification of triglycerides for fat and oil industry and resolution of racemic mixtures used for the synthesis of fine chemicals for the pharmaceutical industry. Therefore, the search for new enzyme sources is important for the development of new enzymes and applications. [source] Comparison of the pharmacological properties of GK11 and MK801, two NMDA receptor antagonists: towards an explanation for the lack of intrinsic neurotoxicity of GK11JOURNAL OF NEUROCHEMISTRY, Issue 4 2007D. Vandame Abstract Over-stimulation of NMDA receptors (NMDARs) is involved in many neurodegenerative disorders. Thus, developing safe NMDAR antagonists is of high therapeutic interest. GK11 is a high affinity uncompetitive NMDAR antagonist with low intrinsic neurotoxicity, shown to be promising for treating CNS trauma. In the present study, we investigated the molecular basis of its interaction with NMDARs and compared this with the reference molecule MK801. We show, on primary cultures of hippocampal neurons, that GK11 exhibits neuroprotection properties similar to those of MK801, but in contrast with MK801, GK11 is not toxic to neurons. Using patch-clamp techniques, we also show that on NR1a/NR2B receptors, GK11 totally blocks the NMDA-mediated currents but has a six-fold lower IC50 than MK801. On NR1a/NR2A receptors, it displays similar affinity but fails to totally prevent the currents. As NR2A is preferentially localized at synapses and NR2B at extrasynaptic sites, we investigated, using calcium imaging and patch-clamp approaches, the effects of GK11 on either synaptic or extrasynaptic NMDA-mediated responses. Here we demonstrate that in contrast with MK801, GK11 better preserve the synaptic NMDA-mediated currents. Our study supports that the selectivity of GK11 for NR2B containing receptors accounts contributes, at least partially, for its safer pharmacological profile. [source] In vitro proliferation of axotomized rat facial nucleus-derived activated microglia in an autocrine fashionJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2006Kazuyuki Nakajima Abstract Transection of rat adult facial nerve leads to an increase in the number of activated microglia in the facial nucleus (FN), with a peak in proliferation 3 days after transection. To investigate the characteristics of these activated microglia, we isolated the cells with high purity from axotomized FN (axFN) 3 days after transection according to the previously reported procedure for explant culture. The isolated microglia exhibited immunocytochemical properties similar to those in vivo, and their numbers increased approximately five- to sevenfold over a period of 10 days without the addition of any mitogens, suggesting that self-reproduction was occurring. Actually, the microglia actively incorporated bromodeoxyuridine (BrdU) and strongly expressed an S-phase-specific protein marker, proliferating cell nuclear antigen (PCNA). To examine the mechanism underlying this proliferation, the expression of the mitogens and specific receptors of the microglia were analyzed in conditioned medium (CM) and cells. Macrophage-colony stimulating factor (M-CSF) and granulocyte macrophage-CSF (GM-CSF) were detected in the CM as well as in the cells. Their specific receptor proteins, c-Fms and GMCSFR,, were also detected in the cell homogenate. These proliferating microglia were not found to produce deleterious factors for neurons. In summary, the microglia isolated from the axFN were found to be proliferative in an autocrine fashion and to have some cellular properties in common with those observed in vivo. © 2006 Wiley-Liss, Inc. [source] DEVELOPMENT OF A SOY-BASED CREAM CHEESEJOURNAL OF TEXTURE STUDIES, Issue 6 2008MUSFIRAH ZULKURNAIN ABSTRACT Various amounts of blended tofu, oil, salt, carrageenan, pectin and maltodextrin were used to develop soy cream cheese products that were trans fat free, with texture properties similar to those of commercial dairy cream cheese. Response surface methodology predicted three formulations with similar spreadability value of that obtained from commercial cheese. Carrageenan and salt were useful to impart the desired firmness, while maltodextrin provided body to the product. Pectin introduced viscous behavior to the final texture but was proven useful in preventing syneresis. Rheological study at 25 and 4C manifested that, although the developed products mimicked the texture of the commercial sample, they had less elasticity. Chemical analysis revealed that the soy cream cheeses had lower fat and higher protein and fiber contents than the commercial sample. They were also stable against syneresis and oil separation over storage of 20 days. PRACTICAL APPLICATIONS The production of soy-based products as alternatives to dairy products has attracted much attention recently. In addition to their lactose-free and reduced fat content, soy-based products are also a good source of protein. There has yet to be any published data on the development of a soy-derivative cream cheese. This paper emphasizes the rheological development of soy cream cheeses in the presence of food hydrocolloids. Their main and interaction effects on texture properties were assessed to mimic those of dairy cream cheese. A comprehensive and systematic approach of formulating the soy cream cheeses was applied by using response surface methodology. In addition, the chemical and nutritional properties of the products were also evaluated and compared with those of the commercial dairy counterpart. [source] Reinforcement of rigid PVC/wood-flour composites with multi-walled carbon nanotubesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2008Omar Faruk Multi-walled carbon nanotubes (CNT) were compounded with PVC by a melt blending process based on fusion behaviors of PVC. The effects of CNT content on the flexural and tensile properies of the PVC/CNT composites were evaluated in order to optimize the CNT content. The optimized CNT-reinforced PVC was used as a matrix in the manufacture of wood-plastic composites. Flexural, electrical, and thermal properties of the PVC/wood-flour composites were evaluated as a function of matrix type (nonreinforced vs. CNT-reinforced). The experimental results indicated that rigid PVC/wood-flour composites with properties similar to those of solid wood can be made by using CNT-reinforced PVC as a matrix. The CNT-reinforced PVC did not influence the electrical and thermal conductivity of the PVC/wood-flour composites. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers. [source] Dwarf nova oscillations and quasi-periodic oscillations in cataclysmic variables , VII.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2009OY Carinae, oscillations in dwarf novae in quiescence ABSTRACT We have observed dwarf nova oscillations (DNOs) in OY Car during outburst, down through decline and beyond; its behaviour is similar to what we have previously seen in VW Hyi, making it only the second dwarf nova to have DNOs late in outburst that continue well into quiescence. There are also occasional examples of DNOs in deep quiescence, well away from outburst , they have properties similar to those during outburst, indicating similar physical causes and structures. We discuss the occurrence of DNOs in other dwarf novae and conclude that DNOs during quiescence are more common than often supposed and exhibit properties similar to those seen in outburst. [source] Elastic-constant systematics in f.c.c. metals, including lanthanides,actinidesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 1 2008Hassel Ledbetter Abstract For f.c.c. metals, using Blackman's diagram of dimensionless elastic-constant ratios, we consider the systematics of physical properties and interatomic bonding. We focus especially on the lanthanides,actinides La, Ce, Yb, Th, U, Pu, those for which we know some monocrystal elastic constants. Their behavior differs from the other f.c.c. metals, and all except La show a negative Cauchy pressure, contrary to most f.c.c. metals, which show a positive Cauchy pressure. Among the lanthanides,actinides, ,-Pu stands apart, consistent with its many odd physical properties. Based on elastic-constant correlations, we suggest that ,-Pu possesses a strong s-electron interatomic-bonding component together with a covalent component. Elastically, ,-Pu shows properties similar to Yb. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Endothelin-1 activates a Ca2+ -permeable cation channel with TRPC3 and TRPC7 properties in rabbit coronary artery myocytesTHE JOURNAL OF PHYSIOLOGY, Issue 3 2007C. M. Peppiatt-Wildman In the present work we used patch pipette techniques to study the properties of a novel Ca2+ -permeable cation channel activated by the potent coronary vasoconstrictor endothelin-1 (ET-1) in freshly dispersed rabbit coronary artery myocytes. With cell-attached recording bath application of 10 nm ET-1 evoked cation channel currents (Icat) with subconductance states of about 18, 34 and 51 and 68 pS, and a reversal potential of 0 mV. ET-1 evoked channel activity when extracellular Ca2+ was the charge carrier, illustrating significant Ca2+ permeability. ET-1-induced responses were inhibited by the ETA receptor antagonist BQ123 and the phospholipase C (PLC) inhibitor U73122. The diacylglycerol analogue 1-oleoyl-2-acetyl- sn -glycerol (OAG) also stimulated Icat, but the protein kinase C (PKC) inhibitor chelerythrine did not inhibit either the OAG- or ET-1-induced Icat. Inositol 1,4,5-trisphosphate (IP3) did not activate Icat, but greatly potentiated the response to OAG and this effect was blocked by heparin. Bath application of anti-TRPC3 and anti-TRPC7 antibodies to inside-out patches markedly inhibited ET-1-evoked Icat, but antibodies to TRPC1, C4, C5 and C6 had no effect. Immunocytochemical studies demonstrated preferential TRPC7 expression in the plasmalemma, whereas TRPC3 was distributed throughout the myocyte, and moreover co-localization of TRPC3 and TRPC7 signals was observed at, or close to, the plasma membrane. Flufenamic acid, Gd3+, La3+ and extracellular Ca2+ inhibited Icat with IC50 values of 2.45 ,m, 3.8 ,m, 7.36 ,m and 22 ,m, respectively. These results suggest that in rabbit coronary artery myocytes ET-1 evokes a Ca2+ -permeable non-selective cation channel with properties similar to TRPC3 and TRPC7, and indicates that these proteins may be important components of this conductance. [source] The Platysma Myocutaneous Flap: Underused Alternative for Head and Neck Reconstruction,THE LARYNGOSCOPE, Issue 7 2002Wayne M. Koch MD Abstract Objectives The use, advantages, and disadvantages of the platysma flap were assessed. Study Design Retrospective review of the medical records of patients undergoing platysma flap reconstruction of the upper aerodigestive tract from 1987 to 2001. Methods Information regarding the tumor, surgical procedure, flap design, and outcome emphasizing complications and function was extracted. Associations between putative risk factors for flap failure and outcome were assessed using the ,2 test. Results Thirty-four patients underwent reconstruction with platysma flaps. Surgical defects included the oropharynx, oral cavity, and hypopharynx. Nine patients had had prior radiation therapy and all had some dissection of the ipsilateral neck. There were 5 postoperative fistulas (15%), flap desquamation was noted in 6 cases (18%), and 2 patients experienced loss of the distal skin closing the donor site. Complications were not associated with prior radiation. Hospital stay ranged from 5 to 21 days (mean, 10 d). There were no returns to the operating room or need for additional reconstruction. All but 1 patient resumed a normal diet within 3 months of surgery. There were no recurrences of cancer in the dissected neck regions. Conclusions The platysma flap is simple and versatile with properties similar to the radial forearm free flap. The rate of complications is similar to other published series, and problems encountered were manageable using conservative methods with excellent functional and cosmetic outcomes. These facts support the contention that the platysma myocutaneous flap can serve as a viable alternative to free tissue transfer and has advantages over pectoralis major pedicled flaps for reconstruction of many head and neck defects. [source] Transport of cytokinins mediated by purine transporters of the PUP family expressed in phloem, hydathodes, and pollen of ArabidopsisTHE PLANT JOURNAL, Issue 1 2003Lukas Bürkle Summary Nucleobases and derivatives like cytokinins and caffeine are translocated in the plant vascular system. Transport studies in cultured Arabidopsis cells indicate that adenine and cytokinin are transported by a common H+ -coupled high-affinity purine transport system. Transport properties are similar to that of Arabidopsis purine transporters AtPUP1 and 2. When expressed in yeast, AtPUP1 and 2 mediate energy-dependent high-affinity adenine uptake, whereas AtPUP3 activity was not detectable. Similar to the results from cell cultures, purine permeases (PUP) mediated uptake of adenine can be inhibited by cytokinins, indicating that cytokinins are transport substrates. Direct measurements demonstrate that AtPUP1 is capable of mediating uptake of radiolabeled trans -zeatin. Cytokinin uptake is strongly inhibited by adenine and isopentenyladenine but is poorly inhibited by 6-chloropurine. A number of physiological cytokinins including trans- and cis- zeatin are also efficient competitors for AtPUP2-mediated adenine uptake, suggesting that AtPUP2 is also able to mediate cytokinin transport. Furthermore, AtPUP1 mediates transport of caffeine and ribosylated purine derivatives in yeast. Promoter,reporter gene studies point towards AtPUP1 expression in the epithem of hydathodes and the stigma surface of siliques, suggesting a role in retrieval of cytokinins from xylem sap to prevent loss during guttation. The AtPUP2 promoter drives GUS reporter gene activity in the phloem of Arabidopsis leaves, indicating a role in long-distance transport of adenine and cytokinins. Promoter activity of AtPUP3 was only found in pollen. In summary, three closely related PUPs are differentially expressed in Arabidopsis and at least two PUPs have properties similar to the adenine and cytokinin transport system identified in Arabidopsis cell cultures. [source] Biochemical and functional analysis of CTR1, a protein kinase that negatively regulates ethylene signaling in ArabidopsisTHE PLANT JOURNAL, Issue 2 2003Yafan Huang Summary CTR1 encodes a negative regulator of the ethylene response pathway in Arabidopsis thaliana. The C-terminal domain of CTR1 is similar to the Raf family of protein kinases, but its first two-thirds encodes a novel protein domain. We used a variety of approaches to investigate the function of these two CTR1 domains. Recombinant CTR1 protein was purified from a baculoviral expression system, and shown to possess intrinsic Ser/Thr protein kinase activity with enzymatic properties similar to Raf-1. Deletion of the N-terminal domain did not elevate the kinase activity of CTR1, indicating that, at least in vitro, this domain does not autoinhibit kinase function. Molecular analysis of loss-of-function ctr1 alleles indicated that several mutations disrupt the kinase catalytic domain, and in vitro studies confirmed that at least one of these eliminates kinase activity, which indicates that kinase activity is required for CTR1 function. One missense mutation, ctr1,8, was found to result from an amino acid substitution within a new conserved motif within the N-terminal domain. Ctr1,8 has no detectable effect on the kinase activity of CTR1 in vitro, but rather disrupts the interaction with the ethylene receptor ETR1. This mutation also disrupts the dominant negative effect that results from overexpression of the CTR1 amino-terminal domain in transgenic Arabidopsis. These results suggest that CTR1 interacts with ETR1 in vivo, and that this association is required to turn off the ethylene-signaling pathway. [source] Cryopreservation of isolated blastomeres and embryonic stem-like cells of Leopard danio, Brachydanio frankeiAQUACULTURE RESEARCH, Issue 4 2010Padmanav Routray Abstract This study aimed at developing a suitable cryopreservation protocol for embryonic stem (ES)-like cells of a tiny freshwater fish Leopard danio (Brachydanio frankei). Embryonic stem (ES)-like cells derived from blastomeres of the early blastulae stage of the developing embryo were cultured in vitro in a medium containing Leibowitz-15 supplemented with 10% foetal bovine serum, leopard danio embryo extract, sodium bicarbonate, sodium selenite, basic fibroblast growth factor, epidermal growth factor and leukaemia inhibitory factor. The ES-like cells showed properties similar to ES cells in other species. They were morphologically small, round to polygonal and present in patches and extensively expressed alkaline phosphatase and stage-specific embryonic antigen. The toxicity and chilling sensitivity of these cells were determined using ethylene glycol (EG), propylene glycol (PG) and glycerol as cryoprotective agents at molar concentrations of 0.6, 1.0, 1.4, 1.8 and 2.0. Among them, 1.8 M EG showed 70% significant viable ES-like cells (P<0.05). The post-thawed cells retained similar properties of non-cryopreserved ES-like cells with a viability rate of 65%. Similarly, blastomeres cryopreserved following the slow cooling rate with EG and PG yielded a viability of more than 70%. [source] Preservation of Muscular and Elastic Artery Distensibility After an Intercontinental Cryoconserved Exchange: Theoretical Advances in Arterial Homograft Generation and UtilizationARTIFICIAL ORGANS, Issue 8 2009Daniel Bia Abstract While the situation of tissue donation and transplantation differs between Latin American and European countries, a common problem is tissue deficiency. Hence, at present, there is a pressing need to generate alternatives so as to increase the possibilities of obtaining the requested materials. Consequently, it would be of significant interest to establish an intercontinental network for tissue exchange, to improve international cooperation, and to help patients that need tissue transplantation, and to evaluate the feasibility of using an intercontinental network for the exchange of cryopreserved arteries (cryografts), preserving the arterial distensibility and ensuring a reduced native artery,cryograft biomechanical mismatch. Distensibility was studied in ovine arteries divided into three groups: intact (in vivo tests, conscious animals), fresh control (in vitro tests immediately after the artery excision, Uruguay), and cryografts (in vitro tests of cryopreserved-transported-defrosted arteries, Spain). Histological studies were performed so as to analyze changes in the endothelial layer and elastic components. The comparison between fresh control and cryografts showed that neither the cryopreservation nor the exchange network impaired the distensibility, despite the expected histological changes found in the cryografts. The comparison between intact and cryografts showed that the cryografts would be capable of ensuring a reduced biomechanical mismatch. The cryopreservation and the intercontinental network designed for artery exchange preserved the arterial distensibility. It could be possible to transfer cryografts between Latin America and Europe to be used in cardiovascular surgeries and/or for tissue banking reprocessing, with basic biomechanical properties similar to those of the fresh and/or native arteries. [source] Improving the Clinical Patency of Prosthetic Vascular and Coronary Bypass Grafts: The Role of Seeding and Tissue EngineeringARTIFICIAL ORGANS, Issue 4 2002Alexander M. Seifalian Abstract: In patients requiring coronary or peripheral vascular bypass procedures, autogenous vein is currently the conduit of choice. If this is unavailable, then a prosthetic material is used. Prosthetic graft is liable to fail due to occlusion of the graft. To prevent graft occlusion, seeding of the graft lumen with endothelial cells is undertaken. Recent advances have also looked at developing a completely artificial biological graft engineered from the patient's cells with properties similar to autogenous vessels. This review encompasses the developments in the two principal technologies used in developing hybrid coronary and peripheral vascular bypass grafts, that is, seeding and tissue engineering. [source] Manganese alters mitochodrial integrity in the hearts of swine marginally deficient in magnesium,BIOFACTORS, Issue 2 2004Kevin B. Miller Abstract It was previously reported that pigs marginally deficient in magnesium (Mg) and fed diets high in manganese (Mn) died suddenly with signs of sudden cardiac death. Manganese, which has properties similar to Mg, may exacerbate Mg-deficiency and be accumulated by mitochondria resulting in ultrastructural damage. The objective of this study was to determine whether deaths of the type previously observed were mediated by adverse interactions of Mn and Mg resulting in ultrastructural damage to the myocardium, alterations in electrocardiographic recordings and tissue retention of Mn, Mg and calcium (Ca). Forty-eight pigs were fed one of six diets in a 2 × 3 factorial arrangement of Mg (100 or 1000 mg Mg/kg) and Mn (5, 50 or 500 mg Mn/kg) for 8 weeks. Left ventricle muscle samples were collected for examination by transmission electron microscopy. No differences in heart muscle ultrastructure were observed between pigs fed low and adequate dietary Mg. However, marked myocardial necrosis and mitochondrial swelling were observed in pigs fed high dietary Mn when combined with low Mg. Feeding low dietary Mg elevated minimum (P < 0.01), maximum (P < 0.05) and average (P < 0.001) heart rates. Low dietary Mg resulted in a 55% probability of a ventricular beat being recorded (P = 0.05) and lower Mg (P < 0.02) and Ca (P < 0.04) contents in heart atria and ventricles. These results suggest that high Mn, when fed in combination with low Mg, disrupts mitochondrial ultrastructure and is associated with the sudden deaths previously reported. [source] | |||||||||||||||||||||||||