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Drastic Reduction (drastic + reduction)
Selected AbstractsScavenging efficiency of rainfall on black carbon aerosols over an urban environmentATMOSPHERIC SCIENCE LETTERS, Issue 3 2005K. Madhavi Latha Abstract Black carbon (BC) aerosols are the optically absorbing part of carbonaceous aerosols that have significantly different optical and radiative properties. The present study addresses the estimation of black carbon aerosol scavenging coefficient by using ground-based measurements over an urban environment of India, namely, Hyderabad. Extensive ground measurements of black carbon have been carried out during January to December 2004 over a tropical urban environment of Hyderabad. Seasonal variations of black carbon aerosol mass concentration showed high values during dry season and low values during monsoon season. The diurnal variations of BC suggest that the concentrations increased by a factor of ,2 during morning and evening hours compared to afternoon hours. Drastic reduction in black carbon aerosol loading has been observed during rainy days. The statistical fit between black carbon aerosol mass concentration and rainfall suggests the reduction of ,3.6 µg/m3 in atmospheric black carbon aerosol loading for every 1-mm increase in rainfall intensity over the study area. The scavenging coefficient of black carbon aerosols is found to be 1.64 × 10,5 s,1. © Crown Copyright 2005. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd. [source] The gluten connection: the association between schizophrenia and celiac diseaseACTA PSYCHIATRICA SCANDINAVICA, Issue 2 2006A. E. Kalaydjian Objective:, Schizophrenia affects roughly 1% of the population and is considered one of the top 10 causes of disability worldwide. Given the immense cost to society, successful treatment options are imperative. Based on initial findings, gluten withdrawal may serve as a safe and economical alternative for the reduction of symptoms in a subset of patients. Method:, A review of the literature relevant to the association between schizophrenia and celiac disease (gluten intolerance) was conducted. Results:, A drastic reduction, if not full remission, of schizophrenic symptoms after initiation of gluten withdrawal has been noted in a variety of studies. However, this occurs only in a subset of schizophrenic patients. Conclusion:, Large-scale epidemiological studies and clinical trials are needed to confirm the association between gluten and schizophrenia, and address the underlying mechanisms by which this association occurs. [source] Physiological and biochemical analyses of microcystin-RR toxicity to the cyanobacterium Synechococcus elongatusENVIRONMENTAL TOXICOLOGY, Issue 6 2004Zhi-quan Hu Abstract Freshwater Microcystis may form dense blooms in eutrophic lakes. It is known to produce a family of related cyclic hepatopeptides (microcystins, MC) that constitute a threat to aquatic ecosystems. Most toxicological studies of microcystins have focused on aquatic animals and plants, with few examining the possible effects of microcystins on phytoplankton. In this study we chose the unicellular Synechococcus elongatus (one of the most studied and geographically most widely distributed cyanobacteria in the picoplankton) as the test material and investigated the biological parameters: growth, pigment (chlorophyll-a, phycocyanin), photosynthetic activity, nitrate reductase activity, and protein and carbohydrate content. The results revealed that microcystin-RR concentrations above 100 ,g · L,1 significantly inhibited the growth of Synechococcus elongatus. In addition, a change in color of the toxin-treated algae (chlorosis) was observed in the experiments. Furthermore, MC-RR markedly inhibited the synthesis of the pigments chlorophyll-a and phycocyanin. A drastic reduction in photochemical efficiency of PSII (Fv/Fm) was found after a 96-h incubation. Changes in protein and carbohydrate concentrations and in nitrate reductase activity also were observed during the exposure period. This study aimed to evaluate the mechanisms of microcystin toxicity on a cyanobacterium, according to the physiological and biochemical responses of Synechococcus elongatus to different doses of microcystin-RR. The ecological role of microcystins as an allelopathic substance also is discussed in the article. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 571,577, 2004. [source] Lewis Acid Induced [2+2] Cycloadditions of Silyl Enol Ethers with ,,,-Unsaturated Esters: A DFT AnalysisEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2005Manuel Arnó Abstract The Lewis acid (LA) induced cycloaddition of trimethysilyl vinyl ether with methyl acrylate has been studied by DFT methods at the B3LYP/6-31G* level. In the absence of an LA, a [4+2] cycloaddition between the silyl enol ether and methyl acrylate in the s-cis conformation takes place through an asynchronous, concerted bond-formation process. This cycloaddition presents a large activation enthalpy of 21.1 kcal,mol,1. Coordination of the LA AlCl3 to the carbonyl oxygen atom of methyl acrylate yields a change of molecular mechanism from a concerted to a two-step mechanism and produces a drastic reduction of the activation energy. This stepwise mechanism is initialized by the nucleophilic attack of the enol ether at the ,-position of methyl acrylate in a Michael-type addition. The very low activation energy (7.1 kcal,mol,1)associated with this nucleophilic attack can be related to the increase of the electrophilicity of the LA-coordinated ,,,-unsaturated ester, which favors the cycloaddition through a polar process. The subsequent ring-closure allows the formation of the corresponding [2+2] and [4+2] cycloadducts. While the [4+2] cycloadduct is formed by kinetic control, the [2+2] cycloadducts are formed by thermodynamic control. The energetic results provide an explanation for the conversion of [4+2] cycloadducts into the thermodynamically more stable [2+2] ones. The cis/trans ratio found for the catalytic [2+2] process is in agreement with the experimental outcome. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Physiological and morphological responses of the soil bacterium Rhodococcus opacus strain PD630 to water stressFEMS MICROBIOLOGY ECOLOGY, Issue 2 2004Héctor M. Alvarez Abstract Rhodococcus opacus PD630 was investigated for physiological and morphological changes under water stress challenge. Gluconate- and hexadecane-grown cells were extremely resistant to these conditions, and survival accounted for up to 300 and 400 days; respectively, when they were subjected to slow air-drying. Results of this study suggest that strain PD630 has specific mechanisms to withstand water stress. Water-stressed cells were sensitive to the application of ethanol, high temperatures and oxidative stress, whereas they exhibited cross-protection solely against osmotic stress during the first hours of application. Results indicate that the resistance programme for water stress in R. opacus PD630 includes the following physiological and morphological changes, among others: (1) energetic adjustments with drastic reduction of the metabolic activity (,39% decrease during the first 24 h and about 90% after 190 days under dehydration), (2) endogenous metabolism using intracellular triacylglycerols for generating energy and precursors, (3) biosynthesis of different osmolytes such as trehalose, ectoine and hydroxyectoine, which may achieve a water balance through osmotic adjustment and may explain the overlap between water and osmotic stress, (4) adjustments of the cell-wall through the turnover of mycolic acid species, as preliminary experiments revealed no evident changes in the thickness of the cell envelope, (5) formation of short fragmenting-cells as probable resistance forms, (6) production of an extracellular slime covering the surface of colonies, which probably regulates internal and external c anges in water potential, and (7) formation of compact masses of cells. This contributes to understanding the water stress resistance processes in the soil bacterium R. opacus PD630. [source] Integrated Optimization by Multi-Objective Particle Swarm OptimizationIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 1 2010Masaru Kawarabayashi Student Member Abstract In this letter, integrated optimization system, a new framework of practical optimization, is expanded to multi-objective optimization problem. This system is used in order to reduce the number of accesses to a simulator. On the basis of simulation results using some typical benchmark problems, it is shown that the proposed integrated optimization system enables to obtain relatively good Pareto solutions with drastic reduction in the number of function calls for evaluating the performance index values of systems. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] An unusual association of pemphigus vulgaris with hyperprolactinemiaINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 10 2002MNAMS, Sujay Khandpur MD A 21-year-old unmarried woman presented with oral ulcerations and generalized, itchy, fluid-filled, skin lesions of 10 days' duration. The lesions ruptured spontaneously, resulting in extensive denuded areas covered by crusts. One month prior to this, she experienced pain and enlargement of both breasts with galactorrhea. Her menstrual cycles were normal initially, but later she developed menstrual irregularities. No past history suggestive of any other systemic or skin disease, including atopy or drug allergies, could be obtained. Her family history was not contributory. Dermatologic examination revealed multiple, flaccid bullae and extensive denuded areas of skin covered with crusts over the scalp, face, trunk, and upper and lower limbs (Fig. 1). Bulla spread sign and Nikolsky's sign were positive. The oral mucosa, including the lips, buccal surface, tongue, and palate, showed multiple erosions covered with necrotic slough. The rest of the mucocutaneous and systemic examination was within normal limits. Figure 1. Extensive erosions and flaccid bullae over the trunk with breast enlargement The patient's diagnostic work-up revealed: hemoglobin, 11.2 g%; total leukocyte count, 7400/mm3; differential leukocyte count, P62L34E2M2; erythrocyte sedimentation rate, 34 mm/h. A peripheral blood smear examination, urinalysis, blood sugar, and renal and liver function tests were normal. Venereal Disease Research Laboratory (VDRL) test and enzyme-linked immunoabsorbent assay (ELISA) for human immunodeficiency virus (HIV) were nonreactive. Antinuclear antibody, lupus erythematosus (LE) cell, rheumatoid factor, and anti-dsDNA levels were normal. Serum protein electrophoresis demonstrated increased levels of immunoglobulin G (IgG) antibody. The serum prolactin level was significantly raised to 139.49 ng/mL (normal, 3.6,18.9 ng/mL). The sex hormone levels, however, including follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, and progesterone, were within normal limits. The thyroid hormone profile was also unaltered. Chest X-ray was normal. Ultrasound of the abdomen and pelvis revealed no visceral abnormality and computerized tomography (CT) scan of the pituitary sella showed no adenoma. Mammography was negative for breast malignancy. A Tzanck smear prepared from the base of the erosion showed multiple acantholytic cells and lymphocytes. Histologic examination from an intact vesicle was suggestive of pemphigus vulgaris (PV), showing a suprabasal cleft with acantholytic cells and the basal layer demonstrating a "row of tombstones" appearance (Fig. 2). Direct immunofluorescence (DIF) revealed the intercellular deposition of IgG and C3 throughout the epidermis in a "fishnet pattern." Indirect immunofluorescence (IIF) test performed on rat esophagus for circulating IgG antibody was positive in a titer of 1 : 120. Figure 2. Photomicrograph showing suprabasal cleft with "row of tombstones" appearance, suggestive of pemphigus vulgaris (hematoxylin and eosin, × 40) Based on the clinical and immunohistological features, a diagnosis of PV with idiopathic hyperprolactinemia was made. The patient was treated with bromocriptine mesylate (Tablet Proctinal, Glaxo Wellcome Ltd, India) at a dose of 2.5 mg twice a day. After 2 months of therapy, significant improvement in the skin lesions was observed. The existing lesions re-epithelialized with a drastic reduction in the number and distribution of new vesicles. However, no change in the mucosal erosions was noticed. IIF test demonstrated a lower antibody titer (1 : 40). The breast complaints also improved with a reduction in serum prolactin level to 6.5 ng/mL. The patient refused further treatment as she experienced nausea and dizziness with bromocriptine. After 2 weeks, the disease relapsed with the appearance of new vesicles over the forearms, abdomen, back, and thighs. She again complained of breast tenderness and galactorrhea, and the serum prolactin level was 95 ng/mL. The IgG titer increased to 1 : 120. Hence, treatment with oral prednisolone (2 mg/kg/day) and bromocriptine (2.5 mg twice a day) with an antiemetic was initiated. After 6 weeks, the skin lesions had cleared completely, the breast symptoms had improved, menses had become regular, and the prolactin level had decreased to 4 ng/mL. IIF test was negative for circulating antibody. Steroids were tapered off and maintenance therapy with bromocriptine at a dose of 2.5 mg/day was continued. [source] Kinetic Analysis of L -Carnosine Formation by ,-AminopeptidasesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010Tobias Heck Abstract The ,,,-dipeptide L -carnosine occurs in high concentrations in long-lived innervated mammalian tissues and is widely sold as a food additive. On a large scale L -carnosine is produced by chemical synthesis procedures. We have established two aqueous enzymatic reaction systems for the preparation of L -carnosine using the dissolved bacterial ,-aminopeptidases DmpA from Ochrobactrum anthropi and BapA from Sphingosinicella xenopeptidilytica as catalysts and investigated the kinetics of the enzyme-catalyzed peptide couplings. DmpA catalyzed the formation of L -carnosine from C-terminally activated ,-alanine derivatives (acyl donor) and L -histidine (acyl acceptor) in an aqueous reaction mixture at pH,10 with high catalytic rates (Vmax=19.2,,mol,min,1 per mg of protein, kcat=12.9,s,1), whereas Vmax in the BapA-catalyzed coupling reaction remained below 1.4,,mol,min,1 per mg of protein (kcat=0.87,s,1). Although the equilibrium of this reaction lies on the side of the hydrolysis products, the reaction is under kinetic control and L -carnosine temporarily accumulated to concentrations that correspond to yields of more than 50% with respect to the employed acyl donor. However, competing nucleophiles caused unwanted hydrolysis and coupling reactions that led to decreased product yield and to formation of various peptidic by-products. The substitution of L -histidine for L -histidine methyl ester as acyl acceptor shifted the pKa of the amino functionality from 9.25 to 6.97, which caused a drastic reduction in the amount of coupling by-products in an aqueous reaction system at pH,8. [source] Microwave-Assisted Synthesis of N-Heterocyclic Carbene- Palladium(II) ComplexesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2010Abstract The microwave-assisted synthesis of two different types of N-heterocyclic carbene-palladium(II) complexes, (NHC)Pd(acac)Cl (NHC=N-heterocyclic carbene; acac=acetylacetonate) and (NHC)PdCl2(3-chloropyridine), has been carried out. A drastic reduction in reaction times (20 to 88 times faster, depending on the complex) was observed when compared to the previously described, conventionally-heated synthesis of these complexes. The protocol also allowed for the synthesis of (IPr)Pd(acac)Cl [IPr=1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene] on a 5-mmol scale in 30,min, with the reactants loaded in air. [source] Subcellular distribution of key enzymes of lipid metabolism during the euthermia-hibernation-arousal cycleJOURNAL OF ANATOMY, Issue 6 2009Anna Suozzi Abstract Mammalian hibernation is a natural, fully reversible hypometabolic state characterized by a drastic reduction of body temperature and metabolic activity, which ensures survival to many species under adverse environmental conditions. During hibernation, many hibernators rely for energy supply almost exclusively on lipid reserves; the shift from carbohydrate to lipid metabolism implies profound rearrangement of the anabolic and catabolic pathways of energetic substrates. However, the structural counterpart of such adaptation is not known. In this study we investigated, by using immunoelectron microscopy, the fine intracellular distribution of two key enzymes involved in lipid metabolism, namely, the fatty acid synthase (FAS) and the long-chain fatty acyl-CoA synthetase (ACSL), in hepatocytes of euthermic, hibernating and arousing hazel dormice. Our results show that the two enzymes are differentially distributed in cellular compartments (cytoplasm, mitochondria and cell nuclei) of hepatocytes during euthermia. Quantitative redistribution of both enzymes among cellular compartments takes place during hibernation and arousal, in accordance with the physiological changes. Interestingly, this redistribution follows different seasonal patterns in cytoplasm, mitochondria and nuclei. In conclusion, our data represent the first quantitative morphological evidence of lipid enzyme distribution in a true hibernator throughout the year cycle, thus providing a structural framework to biochemical changes associated with the hypometabolism of hibernation. [source] Rho kinase activates ezrin-radixin-moesin (ERM) proteins and mediates their function in cortical neuron growth, morphology and motility in vitroJOURNAL OF NEUROSCIENCE RESEARCH, Issue 1 2007Matilda A. Haas Abstract The ezrin-radixin-moesin (ERM) family of proteins contribute to cytoskeletal processes underlying many vital cellular functions. Their previously elucidated roles in non-neuronal cells are an indication of their potential importance in CNS neurons. The specific mechanisms of their activation are unknown, but are likely to depend on factors such as the cell type and biological context. For ERM proteins to become active they must be phosphorylated at a specific C-terminal threonine residue. In non-neuronal cells, several kinases, including the Rho GTPase family member Rho kinase, have been identified as capable of phosphorylating the C-terminal threonine. In these experiments we have investigated specifically the potential role of Rho kinase mediated ERM activation in cortical neurons, utilizing a new pharmacologic inhibitor of Rho kinase and quantitative analysis of aspects of neuronal functions potentially mediated by ERM proteins. Rho kinase inhibition significantly suppressed aspects of neuronal development including neurite initiation and outgrowth, as well as growth cone morphology, with a concomitant loss of phosphorylated ERM immunolabeling in areas associated with neuronal growth. The ability of the Rho kinase inhibitor to decrease the amount of pERM protein was shown by immunoblotting. Post-injury responses were negatively affected by Rho kinase inhibition, namely by a significant decrease in the number of regenerative neurites. We investigated a novel role for ERM proteins in neuron migration using a post-injury motility assay, where Rho kinase inhibition resulted in significant and drastic reduction in neuron motility and phosphorylated ERM immunolabeling. Thus, Rho kinase is an important activator of ERMs in mediating specific neuronal functions. © 2006 Wiley-Liss, Inc. [source] Influence of Starvation on Flesh Quality of Farmed Dentex, Dentex dentexJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2010María Dolores Suárez Dentex (mean initial weight 324 ± 5 g) from a fish farm were divided into two groups (control and fasted). At the end of experimental period (5 wk), dentex were sampled for gross muscle composition and quality analysis. For post mortem muscle analysis, after death, fish were kept in a cold chamber at 4 C, and muscle samples were taken at 4 (prerigor state), 24 (rigor state), and 82 (postrigor state) h after slaughtering. In each fish, textural and biochemical parameters were determined. During starvation, there was a drastic reduction in muscle lipid content and a relative increase of the proteolysis. There were little qualitative changes in the fatty-acid profile of muscle lipids, although a significant increase in n3/n6 ratio in the starved dentex was detected. Starved fish also showed higher muscle firmness, but no differences in pH and water holding capacity were observed. Total and myofibrillar protein and collagen content increased significantly in starved dentex. Firmness during post mortem storage was significantly higher in starved fish, compared with control group. Preslaughtering feeding status showed decisive influence on the evolution dentex muscle quality parameters during cold storage. [source] Splenic marginal zone antigen-presenting cells are critical for the primary allo-immune response to therapeutic factor VIII in hemophilia AJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 11 2009A. NAVARRETE Summary.,Background: Alloimmune responses to intravenously administered protein therapeutics are the most common cause of failure of replacement therapy in patients with defective levels of endogenous proteins. Such a situation is encountered in some patients with hemophilia A, who develop inhibitory anti-factor (F)VIII alloantibodies after administration of FVIII to treat hemorrhages. Objectives: The nature of the secondary lymphoid organs involved in the initiation of immune responses to human therapeutic has not been studied. We therefore investigated this in the case of FVIII, a self-derived exogenous protein therapeutic. Methods: The distribution of intravenously administered FVIII was followed after FVIII-deficient mice were injected with radiolabeled FVIII and using immunohistochemistry. The role of the spleen and antigen-presenting cells (APC) in the onset of the anti-FVIII immune response was analyzed upon splenectomy or treatment of the mice with APC-depleting compounds. Results: FVIII preferentially accumulated in the spleen at the level of metallophilic macrophages in the marginal zone (MZ). Surgical removal of the spleen or selective in vivo depletion of macrophages and CD11c-positive CD8,-negative dendritic cells resulted in a drastic reduction in anti-FVIII immune responses. Conclusions: Using FVIII-deficient mice as a model for patients with hemophilia A, and human pro-coagulant FVIII as a model for immunogenic self-derived protein therapeutics, our results highlight the importance of the spleen and MZ APCs in the initiation of immune responses to protein therapeutics. Identification of the receptors implicated in retention of protein therapeutics in the MZ may pave the way towards novel strategies aimed at reducing their immunogenicity. [source] Immunomodulatory properties of Lactobacillus plantarum and its use as a recombinant vaccine against mite allergyALLERGY, Issue 3 2009P. Rigaux Background:, Selected lactic acid bacteria were reported to prevent atopic dermatitis and experimental asthma but the mechanisms of their immunomodulatory effects are not fully elucidated. In this study, the signaling pathways triggered by Lactobacillus plantarum NCIMB8826 were investigated and the potential use of this strain producing a variant of the mite allergen Der p 1 as live vaccine vehicle was evaluated. Methods:, Mouse bone marrow-derived dendritic cells were stimulated with wild-type or a L. plantarum teichoic acid mutant to evaluate the secretion of cytokines. A recombinant L. plantarum expressing Der p 1 was engineered, its in vitro immunomodulatory properties were characterized and its prophylactic potential was evaluated in a Der p 1-sensitization murine model. Results:, Mouse dendritic cells stimulated by L. plantarum triggered the release of interleukin-10 (IL-10), IL-12 p40, IL-12 p70 and tumor necrosis factor-alpha (TNF-,). IL-12 p40 secretion was dependent on nuclear factor-,B (NF-,B), mitogen-activated protein (MAP) kinases, Toll-like receptor 2 (TLR2), TLR9 and on the bacterial teichoic acid composition. Recombinant L. plantarum producing Der p 1 exhibited similar immunostimulatory properties as wild-type. Prophylactic intranasal pretreatment of mice with this recombinant strain prevented the development of the typical Th2-biased allergic response by a drastic reduction of specific IgE and the induction of protective allergen-specific IgG2a antibodies. Moreover, both wild-type or recombinant L. plantarum reduced airway eosinophilia following aerosolized allergen exposure and IL-5 secretion upon allergen restimulation. Conclusion:, By combining both Th1-type immunostimulatory properties and an efficient allergen delivery capacity, recombinant L. plantarum producing Der p 1 represents a promising vaccine against house dust mite allergy. [source] A variable time transformation method for mixed-integer optimal control problemsOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 3 2006Matthias Gerdts Abstract The article discusses a variable time transformation method for the approximate solution of mixed-integer non-linear optimal control problems (MIOCP). Such optimal control problems enclose real-valued and discrete-valued controls. The method transforms MIOCP using a discretization into an optimal control problem with only real-valued controls. The latter can be solved efficiently by direct shooting methods. Numerical results are obtained for a problem from automobile test-driving that involves a discrete-valued control for the gear shift of the car. The results are compared to those obtained by Branch&Bound and show a drastic reduction of computation time. This very good performance makes the suggested method applicable even for many discretization points. Copyright © 2006 John Wiley & Sons, Ltd. [source] Moisture sorption in moulded fibre trays and effect on static compression strengthPACKAGING TECHNOLOGY AND SCIENCE, Issue 4 2003Gitte Sørensen Abstract This study provides a basic understanding of moisture sorption in moulded fibre packaging for food at varying environmental temperatures and humidities, and the resultant effects on static compression strength. The Guggenheim,Anderson,de Boer (GAB) model is used successfully to construct moisture sorption isotherms in the range 2,25°C and 33,98% relative humidity (% r.h.) (R2 = 0.949,0.999), in which moisture content varies from 5.4 to 28.3,g/100,g dry fibre. Static compression strength (SCS) is substantially affected by changes in moisture content of moulded fibre and decreases exponentially with increasing moisture content. The results indicate a minor hysteresis effect on static compression strength. For adsorption of moisture, a relative strength measure, % SCS (experimental SCS in kg divided by a standard SCS in kg), is given by % SCS = 13.83 + 166.50,·,e,0.0978,m (m is moisture content). The temperature dependence of moisture adsorption is incorporated in the GAB model by relating GAB coefficients, m0 and C, exponentially to temperature, T. By combining this with the exponential model for % SCS, static compression strength can be predicted directly from the surrounding temperature and humidity. Illustrated in a response surface plot the effects of changes in the surroundings are simple and readily accessible, e.g. for packaging designers and sales people. It is noted that an increase in humidity from 50% r.h. to 95% r.h. at constant temperature results in a drastic reduction in % SCS from 100% to 40%, whereas the temperature effect is typically less than 10% SCS when reducing temperature from 25°C to 2°C. Copyright © 2003 John Wiley & Sons, Ltd. [source] Optical properties of single non-polar GaN quantum dotsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 7 2006F. Rol Abstract We present a microphotoluminescence study of non polar GaN/AlN quantum dots (QDs) grown along the [110] axis. Despite the high QD density, single exciton lines could be isolated on the high energy side of the spectral distribution of the QD array emission. Linewidths down to 0.5 meV are reported, which is one order of magnitude lower than previously reported linewidths for polar GaN/AlN QDs. This difference is attributed to the drastic reduction of the internal field in non-polar quantum dots. Temperature dependent measurements were performed up to 180 K. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] High efficiency all-GaAs solar cellPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 2 2010Abderrahmane Belghachi Abstract The reduction of surface recombination in GaAs solar cells is known to be a major concern for photovoltaic cells designers. A common technique used to reduce this effect is to cover the GaAs surface with a wide band gap window layer, therefore the creation of a heterojunction. To avoid a heterojunction with its inconveniences; interface surface states, poor photon absorption in addition to the technological exigencies, one can use an all-GaAs solar cell. In this type of structure, a thin highly doped layer is created at the surface known as a front surface field (FSF). The main role of an FSF layer is to reduce the effect of front surface recombination and the enhancement of light-generated free carriers' collection. This is achieved by the drastic reduction of the effective recombination at the emitter upper boundary. In this work, a simple analytical model is used to simulate the influence of the FSF layer on GaAs solar cell parameters; photocurrent, open circuit voltage and energy conversion efficiency. The effects of the FSF layer doping density and its thickness on the cell performance are discussed by using computed results. Copyright © 2010 John Wiley & Sons, Ltd. [source] Restoration of a Restinga Sandy Coastal Plain in Brazil: Survival and Growth of Planted Woody SpeciesRESTORATION ECOLOGY, Issue 1 2006Luiz R. Zamith Abstract In this article we report the results of an experiment introducing 17 native shrub and tree species into a Brazilian restinga (i.e., coastal sandy plain vegetation). Restingas have been affected by human impact for about 8,000 years, and human occupation for housing, tourism, and land speculation has recently increased in such a way that there is a need for conservation of remnant patches and restoration of degraded areas throughout the coast to protect biodiversity. Our study site is a remnant located in Rio de Janeiro, the second largest city in the country, and has been subjected in the past to deforestation, man-made fire, and sand extraction. Although trees and shrubs predominantly compose natural restinga vegetation, local vegetation after impact was replaced by an exotic grass cover, which meant a drastic reduction in species richness. Thus, in this experiment we removed the grass cover, introduced shrub and tree species, and monitored survival and growth of 20 plants per species for 2 years. Despite the adversities imposed by the nutrient-poor sandy soil, 70% of the species showed high survival percentage and considerable growth. This report on restoration initiatives in the restingas points out the viability of shrub and tree plantation following exotic grass removal as a strategy to restore Brazilian coastal vegetation. [source] Tribological properties of hydrophilic polymer brushes under wet conditionsTHE CHEMICAL RECORD, Issue 4 2010Motoyasu Kobayashi Abstract This article demonstrates a water-lubrication system using high-density hydrophilic polymer brushes consisting of 2,3-dehydroxypropyl methacrylate (DHMA), vinyl alcohol, oligo(ethylene glycol)methyl ether methacrylate, 2-(methacryloyloxy)ethyltrimethylammonium chloride (MTAC), 3-sulfopropyl methacrylate potassium salt (SPMK), and 2-methacryloyloxyethyl phosphorylcholine (MPC) prepared by surface-initiated controlled radical polymerization. Macroscopic frictional properties of brush surfaces were characterized by sliding a glass ball probe in water using a ball-on-plate type tribotester under the load of 0.1,0.49,N at the sliding velocity of 10,5,10,1,m,s,1 at 298,K. A poly(DHMA) brush showed a relatively larger friction coefficient in water, whereas the polyelectrolyte brushes, such as poly(SPMK) and poly(MPC), revealed significantly low friction coefficients below 0.02 in water and in humid air conditions. A drastic reduction in the friction coefficient of polyelectrolyte brushes in aqueous solution was observed at around 10,3,10,2,m,s,1 owing to the hydrodynamic lubrication effect, however, an increase in salt concentration in the aqueous solution led to the increase in the friction coefficients of poly(MTAC) and poly(SPMK) brushes. The poly(SPMK) brush showed a stable and low friction coefficient in water even after sliding over 450 friction cycles, indicating a good wear resistance of the brush film. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 208,216; 2010: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.201000001 [source] Gonadoinhibitory effects of Neb-colloostatin and Neb-TMOF on ovarian development in the mealworm, Tenebrio molitor L.ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 3 2007O. Wasielewski Abstract The gonadostatic action of the peptides Neb-colloostatin (SIVPLGLPVPIGPIVVGPR) and Neb-TMOF (NPTNLH) from Neobellieria bullata was studied in female mealworm Tenebrio molitor. Both peptides potently inhibit ovarian development and terminal oocyte maturation of mated females during their first reproductive cycle. Injection of 4 ,g of Neb-colloostatin or Neb-TMOFNeb-TMOF reduced, at day 4 of the cycle, the size of the terminal oocytes to about half or one third of the normal size in saline-injected controls. In addition, follicular patency was arrested. The injections of Neb-colloostatin and Neb-TMOF also caused a delay to the first ovulation and oviposition as well as a reduction of the number of eggs by about 50% in the first 3 days of the oviposition period. At 4 days after adult emergence, none of the peptides had caused significant changes in protein concentration or composition of the haemolymph. However, both peptides reduced total protein content in ovaries and induced qualitative changes in ovarian protein patterns. Electrophoretic analyses indicated that Neb-colloostatin and Neb-TMOF caused a loss of two proteins (150, 180 kDa) and a drastic reduction of 4 others (39, 43, 47, 130 kDa), which are the most abundant ones in ovaries of control females. On the other hand, they increased the concentration of 2 other polypeptides (65, 70 kDa), which normally occur in insignificant quantities in ovaries. Our results indicate that both peptides have a very similar mode of action despite the differences in their amino acid sequence. They seem to interfere with vitellogenin production by the fat body as well as with vitellogen uptake by the oocytes through modification of patency. Arch. Insect Biochem. Physiol. 64:131,141, 2007. © 2007 Wiley-Liss, Inc. [source] Contraction Process of an Electroactive Actuator Based on a One Microsecond Atomistic Molecular Dynamics SimulationCHEMISTRY - A EUROPEAN JOURNAL, Issue 9 2007David Zanuy Dr. Abstract The contraction process of an electroactive actuator constituted by calix[4]arene units and quaterthiophene segments has been investigated at the microscopic level by using atomistic molecular dynamics simulations in dichloromethane solution using explicit solvent molecules. Results derived from a 1,,s trajectory of the oxidized and deprotonated actuator indicate that the contraction occurs through a non-concerted mechanism in which each actuating units present in the system behave independently. The efficiency of the contraction process can be reduced by the presence of secondary conformational transitions in the calix[4]arene scaffolds. Accordingly, the drastic reduction of the molecular length expected during the contraction process can be limited by such transitions, which involve the rotational isomerism of a phenolate ring. However, such type of conformational transitions does not compromise the actuator power due to its intrinsic capacity to adopt compact molecular arrangements. On the other hand, the rate of the contraction process is influenced by the presence of solvent molecules, which have been found to reduce it by a factor of about 1000. [source] Expression and function of the ST2 gene in a murine model of allergic airway inflammationCLINICAL & EXPERIMENTAL ALLERGY, Issue 10 2002K. Oshikawa Summary Background We have recently reported that soluble ST2 protein levels are elevated in the sera of patients with asthma, and correlate well with the severity of asthma exacerbation. However, the role, function, and kinetics of soluble ST2 expression in asthma remain unclear. Objective The objective of the present study was to clarify the function and kinetics of soluble murine (m) ST2 expression in a murine asthma model. Methods We analyzed the kinetics of gene and protein expression of mST2 in sera or lung tissue after allergen (ovalbumin; OVA) challenge in a murine model of allergic airway inflammation, the effects of mST2 protein on OVA-induced Th2 cytokine production in vitro from splenocytes of sensitized mice, and the effects of soluble mST2 on Th2-dependent allergic airway inflammation by in vivo gene transfer of mST2. Results Serum mST2 protein levels increased to the maximal level 3 h after the allergen challenge, before serum IL-5 levels peaked. The mRNA expression of mST2 in lung tissue was induced after the allergen challenge, while that in the spleen was constitutively detected. Furthermore, pre-treatment with mST2 protein significantly inhibited the production of IL-4 and IL-5, but not IFN-,, from OVA-stimulated splenocytes in vitro, and intravenous mST2 gene transfer resulted in a drastic reduction in the number of eosinophils and in the levels of IL-4 and IL-5 in bronchoalveolar lavage fluid, compared with those in response to transfer of non-coding plasmid vector or of lipid alone. Conclusion These results suggest that increases in endogenous mST2 protein after allergen exposure may modulate Th2-mediated airway inflammation, and that in vivo gene transfer of mST2 can be applicable to use in a novel immunotherapy for allergic diseases. [source] Feedback effects of chronic browsing on life-history traits of a large herbivoreJOURNAL OF ANIMAL ECOLOGY, Issue 4 2008M. Anouk Simard Summary 1Increasing ungulate populations are affecting vegetation negatively in many areas, but few studies have assessed the long-term effects of overbrowsing on individual life-history traits of ungulates. 2Using an insular population of white-tailed deer (Odocoileus virginianus Zimmermann; Anticosti, Québec, Canada) introduced in 1896, and whose density has remained high since the first evidence of severe browsing in the 1930s, we investigated potential feedbacks of long-term and heavy browsing on deer life-history traits. 3We assessed whether chronic browsing contributed to a decline of the quality of deer diet in early autumn during the last 25 years, and evaluated the impacts of reduced diet quality on deer body condition and reproduction. 4Rumen nitrogen content declined 22% between two time periods, 1977,79 and 2002,04, indicating a reduction in diet quality. 5After accounting for the effects of year within the time period, age and date of harvest in autumn, peak body mass of both sexes declined between the two time periods. At the end of November, males were on average 12% heavier and adult does 6% heavier in 1977,79 than in 2002,04. Hind foot length did not vary between time periods. 6The probability of conception increased 15% between the two time periods, but litter size at ovulation declined 7%, resulting in a similar total number of ovulations in 2002,04 and in 1977,79. 7Our results suggest that following a decline in diet quality, white-tailed deer females modified their life-history strategies to maintain reproduction at the expense of growth. 8Deer appear to tolerate drastic reductions in diet quality by modifying their life history traits, such as body mass and reproduction, before a reduction in density is observed. Such modifications may contribute to maintain high population density of large herbivores following population irruption. [source] Soil conservation in Polylepis mountain forests of Central Argentina: Is livestock reducing our natural capital?AUSTRAL ECOLOGY, Issue 4 2010DANIEL RENISON Abstract Mountain forests and their soils provide ecological services such as maintenance of biodiversity, provision of clean water, carbon capture and forage for livestock rearing, which is one of the principal economic activities in mountain areas. However, surprisingly little is known about livestock impact in South American mountain forest soils. With the aim of understanding how livestock and topography influence patterns of forest cover, soil compaction, soil loss and soil chemical properties, we analysed these parameters in 100 Polylepis australis woodland plots situated in the humid subtropical mountains of Central Argentina. We used distance from the nearest ranch as an objective index of historical livestock impact and measured standard topographic variables. Our main results reveal that distance from ranch in all cases partly explains tree canopy cover, soil loss, soil compaction and soil chemical properties; suggesting a strong negative effect of livestock. Intermediate altitudes had more tree canopy cover, while landscape roughness , a measure of the variability in slope inclination and aspect , was negatively associated to soil impedance and acidity, and positively associated to soil organic matter content. Finally, flatter areas were more acid. We conclude that livestock has had a substantial influence on forest soil degradation in the Mountains of Central Argentina and possibly other similar South American mountains. Soil degradation should be incorporated into decision making when considering long-term forest sustainability, or when taking into account retaining livestock for biodiversity conservation reasons. Where soil loss and degradation are ongoing, we recommend drastic reductions in livestock density. 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