Home About us Contact
|
Home About us Contact | ||
|
|
||
Very Important Role (very + important_role)
Selected AbstractsInfluence of the Wall Characteristics on the Development of MARFE in TokamaksCONTRIBUTIONS TO PLASMA PHYSICS, Issue 7-9 2006O. Marchuk Abstract Multifaceted asymmetric radiation from the edge (MARFE) normally develops in fusion devices close to the density limit. MARFE is considered a result of thermal instabilities excited under critical conditions through different mechanisms: impurity radiation, recycling of neutral particles, anomalous transport of charged particles and energy. Recent experiments on tokamaks TEXTOR and JET show that plasma-wall interaction, leading to release of recycling neutrals and impurities, plays a very important role for the formation of MARFE. In the present contribution we develop further the MARFE models based on the instability of particle recycling on the tokamak wall by including a simple description for the release of recycling neutrals from the wall surface into the plasma. This development takes into account the time delay between the out flow of charged particles from the plasma and in flux of neutrals. The linear stability analysis shows that this does not change the critical plasma density for the MARFE formation but modifies significantly the growth rate of unstable perturbations developing when the density exceeds the threshold. These findings are confirmed in a non-linear consideration by solving the equations for the particle, momentum and energy transfer in the plasma coupled with the wall particle balance equations. This is done in a one-dimensional approximation by taking into account the variation of the main plasma parameters in the poloidal direction and making averaging in the radial direction over the plasma edge width of the penetration depth of neutrals. The intrinsic poloidal asymmetry of the system, defining the MARFE localization, is introduced by the Shafranov shift of magnetic flux surfaces. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Development and experimental validation of a conceptual model for biotrickling filtration of H2SENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2003Seongyup Kim A dynamic model that describes the behavior of high-performance hydrogen sulfide (H2S)-degrading biotrickling filters for odor control was developed. The model attempts to accurately describe pollutant mass transfer in the biotrickling filter, i.e., external mass transfer resistances, and both direct gas-biofilm and gas-liquid-biofilm mass transfer were considered. In order to calibrate the model, an innovative differential biotrickling filter was constructed in which the effect of air velocity on the removal of H2S could be studied. Model outputs were compared with experimental data to determine the sensitivity of the system to selected parameters. At low H2S concentration, diffusion of H2S within the biofilm, and biofilm thickness were the major governing factors among nine considered model parameters. At higher H2S concentrations and lower air flow rates, external mass transfer played a very important role. This new finding, confirmed experimentally, has important implications, as it proves that the performance limit of H2S degrading biotrickling filters has not yet been reached. [source] Automated normalized FLAIR imaging in MRI-negative patients with refractory focal epilepsyEPILEPSIA, Issue 6 2009Niels K. Focke Summary Background:, Patients with focal epilepsy that is refractory to medical treatment are often considered candidates for resective surgery. Magnetic resonance imaging (MRI) has a very important role in the presurgical work-up of these patients, but is unremarkable in about one-third of cases. These patients are often deferred from surgery or have a less positive outcome if surgery is eventually undertaken. The aim of this study was to evaluate our recently described voxel-based technique using routine T2-FLAIR (fluid-attenuated inversion-recovery) scans in MRI-negative patients and to compare the results with video-EEG (electroencephalography) telemetry (VT) findings. Methods:, We identified 70 epilepsy patients with refractory focal seizures who underwent VT and had a normal routine MRI. T2-FLAIR scans were bias-corrected, and intensity and spatially normalized (nFSI) using Statistical Parametric Mapping 5 (SPM5) as previously described. Individual scans were then compared against a set of 25 normal controls using a voxel-based method. Results:, SPM5 identified 10 patients with suprathreshold clusters (14.3%). In 50% of these there was concordance between the lobe of the most significant cluster and the presumed lobe of seizure onset, as defined by VT. All cases were concordant with respect to lateralization of the putative focus. Conclusion:, Using nFSI we identified focal structural cerebral abnormalities in 11.4% of patients with refractory focal seizures, and normal conventional MRI, that were fully or partially concordant with scalp VT. This voxel-based analysis of FLAIR scans, which are widely available, could provide a useful tool in the presurgical evaluation of epilepsy patients. Ongoing work is to compare these imaging findings with the results of intracranial EEG and histology of surgical resections. [source] IL-6: Regulator of Treg/Th17 balanceEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2010Akihiro Kimura Abstract IL-6 is a pleiotropic cytokine involved in the physiology of virtually every organ system. Recent studies have demonstrated that IL-6 has a very important role in regulating the balance between IL-17-producing Th17 cells and regulatory T cells (Treg). The two T-cell subsets play prominent roles in immune functions: Th17 cell is a key player in the pathogenesis of autoimmune diseases and protection against bacterial infections, while Treg functions to restrain excessive effector T-cell responses. IL-6 induces the development of Th17 cells from naïve T cells together with TGF-,; in contrast, IL-6 inhibits TGF-,-induced Treg differentiation. Dysregulation or overproduction of IL-6 leads to autoimmune diseases such as multiple sclerosis (MS) and rheumatoid arthritis (RA), in which Th17 cells are considered to be the primary cause of pathology. Given the critical role of IL-6 in altering the balance between Treg and Th17 cells, controlling IL-6 activities is potentially an effective approach in the treatment of various autoimmune and inflammatory diseases. Here, we review the role of IL-6 in regulating Th17/Treg balance and describe the critical functions of IL-6 and Th17 in immunity and immune-pathology. [source] Neural selectivity for hue and saturation of colour in the primary visual cortex of the monkeyEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2000Akitoshi Hanazawa Abstract In the inferior temporal (IT) cortex of monkeys, which has been shown to play a critical role in colour discrimination, there are neurons sensitive to a narrow range of hues and saturation. By contrast, neurons in the retina and the parvocellular layer of the lateral geniculate nucleus (pLGN) encode colours in a way that does not provide explicit representation of hue or saturation, and the process by which hue- and saturation-selectivity is elaborated remains unknown. We therefore tested the colour-selectivity of neurons in the primary visual cortex (V1) and compared it with those of pLGN and IT neurons. Quantitative analysis was performed using a standard set of colours, systematically distributed within the CIE (Commission Internationale de l'Eclairage)-xy chromaticity diagram. Selectivity for hue and saturation was characterized by analysing response contours reflecting the overall distribution of responses across the chromaticity diagram. We found that the response contours of almost all pLGN neurons were linear and broadly tuned for hue. Many V1 neurons behaved similarly; nonetheless, a considerable number of V1 neurons had clearly curved response contours and were selective for a narrow range of hues or saturation. The relative frequencies of neurons exhibiting various selectivities for hue and saturation were remarkably similar in the V1 and IT cortex, but were clearly different in the pLGN. Thus, V1 apparently plays a very important role in the conversion of colour signals necessary for generating the elaborate colour selectivity observed in the IT cortex. [source] Output of the Spanish Cortes (1979,2000): A case of adaptation to party governmentEUROPEAN JOURNAL OF POLITICAL RESEARCH, Issue 4 2006MANUEL SANCHEZ DE DIOS It mainly examines the output of the lower chamber due to the asymmetrical bicameralism and weak status of the Senate. In Spain, the legislative output has been dependent on different situations of party government. In general terms, the Cortes have been always very active in controlling the executive and its participation in law-making was highly relevant when there was a minority government. Because parties are central actors in parliament and due to the strong party discipline in the Spanish case, the author mainly studied parliament output from the viewpoint of strategies of opposition parties. Sometimes parties behaved in parliament procedures in a competitive way, while in others they behave cooperatively. There was a great variety of patterns of strategic behaviour on account of the different situations of party government and the diverse opposition parties. Half of the parliaments had minority governments in which minority parties played a very important role by supporting the government in parliament; however, the main opposition party was never the same since there were two changes of government. [source] Carbonyl cyanide m -chlorophenylhydrazone induced calcium signaling and activation of plasma membrane H+ -ATPase in the yeast Saccharomyces cerevisiaeFEMS YEAST RESEARCH, Issue 4 2008Michele B.P. Pereira Abstract The plasma membrane H+ -ATPase from Saccharomyces cerevisiae is an enzyme that plays a very important role in the yeast physiology. The addition of protonophores, such as 2,4-dinitrophenol (DNP) and carbonyl cyanide m -chlorophenylhydrazone (CCCP), also triggers a clear in vivo activation of this enzyme. Here, we demonstrate that CCCP-induced activation of the plasma membrane H+ -ATPase shares some similarities with the sugar-induced activation of the enzyme. Phospholipase C and protein kinase C activities are essential for this activation process while Gpa2p, a G protein involved in the glucose-induced activation of the ATPase, is not required. CCCP also induces a phospholipase C-dependent increase in intracellular calcium. Moreover, we show that the availability of extracellular calcium is required for CCCP stimulation of H+ -ATPase, suggesting a possible connection between calcium signaling and activation of ATPase. [source] Evaluation of a job-aiding tool in inspection systemsHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 1 2008Edem Tetteh Visual inspection plays a very important role in ensuring quality in the manufacturing and service industries. Two determinants of inspection performance are visual search and decision-making. Improvement in any one of the components will have an impact on system performance. Job-aids, accompanied by training, have proven to be effective in enhancing accuracy and reducing search time in visual inspection systems. This article aims to investigate the effects of search strategy along with task complexity and pacing on inspection performance using a job-aiding tool. To facilitate the experiments, an enhanced job-aiding tool in a simulated visual inspection environment was developed. This tool enables an inspector to track his or her search path in visual inspection systems. A pilot study and two experiments were conducted using this tool. The pilot study examined the effectiveness of the job-aiding tool. The first experiment studied the effect of search strategy and task complexity on inspection system performance and the second experiment studied the impact of search strategy, task complexity, and pacing on system performance. Results from this research can be used to better design an inspection system. © 2007 Wiley Periodicals, Inc. [source] Hydrometeorological behaviour of pine and larch forests in eastern SiberiaHYDROLOGICAL PROCESSES, Issue 1 2004Shuko Hamada Abstract Seasonal changes in the water and energy exchanges over a pine forest in eastern Siberia were investigated and compared with published data from a nearby larch forest. Continuous observations (April to August 2000) were made of the eddy-correlation sensible heat flux and latent heat flux above the canopy. The energy balance was almost closed, although the sum of the turbulent fluxes sometimes exceeded the available energy flux (Rn , G) when the latent heat flux was large; this was related to the wind direction. We examined the seasonal variation in energy balance components at this site. The seasonal variation and magnitude of the sensible heat flux (H) was similar to that of the latent heat flux (,E), with maximum values occurring in mid-June. Consequently, the Bowen ratio was around 1·0 on many days during the study period. On some clear days just after rainfall, ,E was very large and the sum of H and ,E exceeded Rn , G. The evapotranspiration rate above the dry canopy from May to August was 2·2 mm day,1. The contributions of understory evapotranspiration (Eu) and overstory transpiration (Eo) to the evapotranspiration of the entire ecosystem (Et) were both from 25 to 50% throughout the period analysed. These results suggest that Eu plays a very important role in the water cycle at this site. From snowmelt through the tree growth season (23 April to 19 August 2000), the total incoming water, comprised of the sum of precipitation and the water equivalent of the snow at the beginning of the melt season, was 228 mm. Total evapotranspiration from the forest, including interception loss and evaporation from the soil when the canopy was wet, was 208,254 mm. The difference between the incoming and outgoing amounts in the water balance was from +20 to ,26 mm. The water and energy exchanges of the pine and larch forest differed in that ,E and H increased slowly in the pine forest, whereas ,E increased rapidly in the larch forest and H decreased sharply after the melting season. Consequently, the shape of the Bowen ratio curves at the two sites differed over the period analysed, as a result of the differences in the species in each forest and in soil thawing. Copyright © 2003 John Wiley & Sons, Ltd. [source] CLONING AND EXPRESSION OF SPODOPTERA LITURA UBIQUITIN GENEINSECT SCIENCE, Issue 1 2003LI Zhao-fei Abstract Ubiquitin (UBI) plays a very important role in regulated non-lysosomal ATP dependent protein degradation. In the present work, the coding sequence of Spodoptera litura UBI gene was isolated (GenBank Accession No. AF436066). The length of this ORF is 228bp, encoding a protein with Mr of 8.56 kD and isoelectric point of 6.56. Multiple sequence alignment indicated that S. litura UBI is very similar to the homologous proteins of other eukaryotic species and it has 84% identity with S. litura nucleopolyhedrovirus (SpltMNPV) UBI at amino acid level. RT-PCR analysis showed that S. litura UBI gene is ubiquitously expressed in larva tissues which are susceptible to SpltMNPV infection. By constructing E. coli expression vector, S. litura UBI was highly expressed and the recombinant protein was purified using Ni-NTA resin column, and currently further study on the function of S. litura UBI in SpltMNPV infection is underway. [source] Determining elastic constants of transversely isotropic rocks using Brazilian test and iterative procedureINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 3 2008Yen-Chin Chou Abstract The elastic constants of rocks are the basic parameters for rock mechanics, and play a very important role in engineering design. There are many laboratory methods to determine the elastic constants of transversely isotropic rocks, and the Brazilian test is a popular method. This paper presented a method combination of the Brazilian test, back calculation, and iterative procedure to evaluate the five independent elastic constants of transversely isotropic rocks in laboratory. The strain data at the centre of discs were obtained using Brazilian test. The stresses at the centre of discs were computed using numerical programs. By using back calculation, the temporary elastic constants were computed after the stresses and stains were substituted into elastic mechanics equations. After iterative procedure, the convergent values of the elastic constants can be obtained. One numerical example and three experimental cases were proposed to show the applicability of this method. The convergent values of the five independent elastic constants can be obtained in no more than 10 iterative cycles. The results coming from numerical analysis method exhibited satisfactory outcome in accordance with those of generalized reduced gradient method. The merits of this method include convenient specimen preparation of the Brazilian test, simple iterative procedure, and readily available commercially numerical programs, so that this method can be easily popularized in research and engineering analysis. Copyright © 2007 John Wiley & Sons, Ltd. [source] An integrated parameter identification method combined with sensor placement designINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 12 2008Yiqian Li Abstract Material parameter identification based on in situ measurements plays a very important role in engineering. Since noises are inevitable in measurements and the parameter identification is inherently ill posed, it is necessary to consider some methods to stabilize the identification procedure. One choice is properly designing the sensor placement, which has attracted much attention over the past 30 years. Most existing sensor placement design methods are based on certain sensitivity analysis, which commonly requires evaluating Jacobian matrix for given parameters. However, the ,true' values of parameters are unknown at that moment, because sensor placement design is carried out before the parameter identification. Consequently, roughly estimated ,true' parameters have to be used and less optimal sensor placement could be obtained. To solve this problem, this paper presents an integrated method in which the parameter identification and sensor placement design are carried out alternatively. The validity of the proposed method is illustrated by two simple academic examples. Then it is implemented to detect damages in a real highway bridge. Copyright © 2007 John Wiley & Sons, Ltd. [source] Numerical methods for large-eddy simulation in general co-ordinatesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 1 2004Gefeng Tang Abstract Large scale unsteady motions in many practical engineering flows play a very important role and it is very unlikely that these unsteady flow features can be captured within the framework of Reynolds averaged Navier,Stokes approach. Large-eddy simulation (LES) has become, arguably, the only practical numerical tool for predicting those flows more accurately since it is still not realistic to apply DNS to practical engineering flows with the current and near future available computing power. Numerical methods for the LES of turbulent flows in complex geometry have been developed and applied to predict practical engineering flows successfully. The method is based on body-fitted curvilinear co-ordinates with the contravariant velocity components of the general Navier,Stokes equations discretized on a staggered orthogonal mesh. For incompressible flow simulations the main source of computational expense is due to the solution of a Poisson equation for pressure. This is especially true for flows in complex geometry. A multigrid 3D pressure solver is developed to speed up the solution. In addition, the Poisson equation for pressure takes a simpler form with no cross-derivatives when orthogonal mesh is used and hence resulting in increased convergence rate and producing more accurate solutions. Copyright © 2004 John Wiley & Sons, Ltd. [source] Study of conformational and optical rotation for the alaninamideINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 4 2007Shulei Zhao Abstract Six stationary points of alaninamide have been located on the potential surface energy (PES) at the B3LYP/6-311++G(2d,2p) level of theory both in the gas phase and in aqueous solution. In the aqueous solution, to take the water solvent effect into account, the polarizable continuum model (PCM) method has been used. Accurate geometric structures and their relative stabilities have been investigated. The results show that the intramolecular hydrogen bond plays a very important role in stabilizing the global minimum of the alaninamide. Moreover, the consistent result in relative energy using high-level computations, including the MP2 and MP3 methods with the same basis set [6-311++G(2d,2p)], indicates that the B3LYP/6-311++G(d,p) level may be applied to the analogue system. More importantly, the optical rotation of the optimized conformers (both in the gas phase and in aqueous solution) of alaninamide have been calculated using the density functional theory (DFT) and Hartree,Fock (HF) method at various basis sets (6-31+G*, 6-311++G(d,p), 6-311++G(2d,2p) and aug-cc-pvdz). The results show that the selection of the computation method and the basis set in calculation has great influence on the results of the optical rotations. The reliability of the HF method is less than that of DFT, and selecting the basis set of 6-311++G(2d,2p) and aug-cc-pvDZ produces relative reliable results. Analysis of the computational results of the structure parameters and the optical rotations yields the conclusion that just the helixes in molecules caused the chiral molecules to be optical active. The Boltzmann equilibrium distributions for the six conformers (both in the gas phase and in the aqueous solution) are also carried out. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [source] Flood control and land use management in Mengwa retention area, Huai River Basin,IRRIGATION AND DRAINAGE, Issue 4 2004Han Ruiguang Contrôle des crues; gestion de l'occupation du sol; aire d'épandage Abstract Retention areas have a very important role in flood alleviation in the Huai River Basin. With economic and societal development the former retention areas have been developed and some of them even became very important urban areas. When floods come, there is a lot of damage. The government has realized that the flood control standards in the whole river basin are low and has made a plan to increase flood control standards for the Mengwa retention area. The design water level will be 28.00,m+MSL at Runheji. In light of this the use of the Mengwa retention area needs to be considered. To arrive at decisions that reduce flood damage, one should take into account the following uncertainties: the river discharge, the flood damage given the discharge, the downstream water level given the discharge, and the costs of constructing embankments and dredging the river. By using the DUFLOW model and a GIS model, the present situation and the alternative development options have been analysed. How to use the Mengwa retention area is also discussed. Copyright © 2004 John Wiley & Sons, Ltd. Les zones d'expansion jouent un rôle important dans la réduction des crues du fleuve Huia. Ces zones ont connu le même développement économique et social que le reste de la région, et certaines sont maintenant fortement urbanisées. Les crues y provoquent beaucoup de dégâts. Le gouvernement a pris conscience que les critères pour contrôler les crues dans le bassin versant sont insuffisants, et a élaboré un plan pour améliorer ce contrôle dans l'aire d'épandage de Mengwa. Le niveau d'eau de référence retenu est à la cote 28,m, prise à Runheji. Ceci implique de reconsidérer l'utilisation de la zone d'expansion. Les décisions permettant de réduire les dégâts dus aux crues ont été élaborées à partir des paramètres suivants: débit du fleuve, relation entre le débit et les dégâts dus aux crues, niveau d'eau en aval, coûts de renforcement des digues, coût du dragage. La situation actuelle et les possibilités d'amélioration ont été analysées avec le modèle DUFLOW et un SIG. L'utilisation de la zone d'expansion de Mwenga est examinée également. Copyright © 2004 John Wiley & Sons, Ltd. [source] Evolution of the structure and function of the vertebrate tongueJOURNAL OF ANATOMY, Issue 1 2002Shin-ichi Iwasaki Abstract Studies of the comparative morphology of the tongues of living vertebrates have revealed how variations in the morphology and function of the organ might be related to evolutional events. The tongue, which plays a very important role in food intake by vertebrates, exhibits significant morphological variations that appear to represent adaptation to the current environmental conditions of each respective habitat. This review examines the fundamental importance of morphology in the evolution of the vertebrate tongue, focusing on the origin of the tongue and on the relationship between morphology and environmental conditions. Tongues of various extant vertebrates, including those of amphibians, reptiles, birds and mammals, were analysed in terms of gross anatomy and microanatomy by light microscopy and by scanning and transmission electron microscopy. Comparisons of tongue morphology revealed a relationship between changes in the appearance of the tongue and changes in habitat, from a freshwater environment to a terrestrial environment, as well as a relationship between the extent of keratinization of the lingual epithelium and the transition from a moist or wet environment to a dry environment. The lingual epithelium of amphibians is devoid of keratinization while that of reptilians is keratinized to different extents. Reptiles live in a variety of habitats, from seawater to regions of high temperature and very high or very low humidity. Keratinization of the lingual epithelium is considered to have been acquired concomitantly with the evolution of amniotes. The variations in the extent of keratinization of the lingual epithelium, which is observed between various amniotes, appear to be secondary, reflecting the environmental conditions of different species. [source] Effects of addition of acrylic compatibilizer on the morphology and mechanical behavior of amorphous polyamide/SAN blendsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010D. Becker Abstract Amorphous polyamide (aPA)/acrylonitrile-styrene copolymer (SAN) blends were prepared using methyl methacrylate-maleic anhydride copolymer MMA-MA as compatibilizer. The aPA/SAN blends can be considered as a less complex version of the aPA/ABS (acrylonitrilebutadiene-styrene) blends, due to the absence of the ABS rubber phase in the SAN material. It is known that acrylic copolymer might be miscible with SAN, whereas the maleic anhydride groups from MMA-MA can react in situ with the amine end groups of aPA during melt blending. As a result, it is possible the in situ formation of aPA-g-MMA-MA grafted copolymers at the aPA/SAN interface during the melt processing of the blends. In this study, the MA content in the MMA-MA copolymer and its molecular weight was varied independently and their effects on the blend morphology and stress,strain behavior were evaluated. The morphology of the blends aPA/SAN showed a minimum in the SAN particle size at low amounts of MA in the compatibilizer, however, as the MA content in the MMA-MA copolymer was increased larger SAN particle sizes were observed in the systems. In addition, higher MA content in the compatibilizer lead to less ductile aPA/SAN blends under tensile testing. The results shown the viscosity ratio also plays a very important role in the morphology formation and consequently on the properties of the aPA/SAN blends studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Influences of passivating elements on the corrosion and biocompatibility of super stainless steelsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2008Young-Ran Yoo Abstract Biometals need high corrosion resistance since metallic implants in the body should be biocompatible and metal ion release should be minimized. In this work, we designed three kinds of super stainless steel and adjusted the alloying elements to obtain different microstructures. Super stainless steels contain larger amounts of Cr, Mo, W, and N than commercial alloys. These elements play a very important role in localized corrosion and, thus, their effects can be represented by the "pitting resistance equivalent number (PREN)." This work focused on the behavior which can arise when the bare surface of an implant in the body is exposed during walking, heavy exercise, and so on. Among the experimental alloys examined herein, Alloy Al and 316L stainless steels were mildly cytotoxic, whereas the other super austenitic, duplex, and ferritic stainless steels were noncytotoxic. This behavior is primarily related to the passive current and pitting resistance of the alloys. When the PREN value was increased, the passivation behavior in simulated body solution was totally different from that in acidic chloride solution and, thus, the Cr2O3/Cr(OH)3 and [Metal oxide]/[Metal + Metal oxide] ratios of the passive film in the simulated body solution were larger than those in acidic chloride solution. Also, the critical current density in simulated body solution increased and, thus, active dissolution may induce metal ion release into the body when the PREN value and Ni content are increased. This behavior was closely related to the presence of EDTA in the simulated body solution. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] Grb10 adapter protein as regulator of insulin-like growth factor receptor signalingJOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2003Andrea Morrione Grb10 is a member of a superfamily of adapter proteins that includes Grb10, 7, 14, and a protein of Caenorhabditis elegans called Mig10. Grb10 proteins are binding partners for several trans-membrane tyrosine-kinase receptors, including the insulin-like growth factor receptor (IGF-IR) and the insulin receptor (IR). Many recent reports have suggested a very important role of Grb10 in regulating IGF-IR signaling. In this review, we will focus on the role of Grb10 in IGF-I-induced mitogenesis and we will discuss the recent findings that show the involvement of Grb10 in the regulation of ligand-induced ubiquitination, internalization, and stability of the IGF-IR. J. Cell. Physiol. 197: 307,311, 2003© 2003 Wiley-Liss, Inc. [source] Influence of cosurfactant in microemulsion systems for color removal from textile wastewaterJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2005Leocadia Terezinha Cordeiro Beltrame Abstract Microemulsion systems have proved very efficient in color removal from textile wastewater using n -butyl alcohol as cosurfactant. The cosurfactant has a very important role in microemulsified systems, as it is responsible for their stability, mainly in systems formed by ionic surfactants. Although very efficient, n -butyl alcohol is partially soluble in water, which would permit its passage to the effluent. In this work, isoamyl and octyl alcohols, due to their lower solubility in water, were used as cosurfactants to evaluate their influence in color removal. The colorimetry system used was the CIE L*a*b* (CIELAB) color space and CIE L*a*b* color difference (,E*ab). The wastewater used in this study was the reactive exhausted dye liquor from a dye house (first discharge) containing Procion Yellow H-E4R (CI Reactive Yellow 84), Procion Blue H-ERD (CI Reactive Blue 160) and Procion Red H-E3B (CI Reactive Red 120). The obtained results were modeled using an experimental planning (the Scheffé net) and evaluated through isoresponse diagrams by correlation graphs between experimental values and those obtained by the models with an error lower than 4%. All the optimized systems were very efficient and more than 94% of the dyes contained in the effluent were removed. The microemulsion load capacity was determined using a synthetic solution containing, the same dyes present in the reactive exhausted dyebath, but 200 times concentrated, and the dyes extraction was more than 99.6%. By comparing n -butyl, isoamyl and octyl alcohols, it was observed that the system using isoamyl alcohol presented slightly better color removal and much higher load capacity than the n -butyl and octyl alcohols. Copyright © 2004 Society of Chemical Industry [source] Analysis of degraded papers by non-destructive spectroscopic techniquesJOURNAL OF RAMAN SPECTROSCOPY, Issue 10 2006Marina Bicchieri Abstract Scientific approach to cultural heritage conservation is very important for cultural reasons and also in order to avoid mistakes in restoration work. Acidity and oxidation play a very important role in paper conservation. Deacidification is a widely used method to remove acidity on aged papers, but if a large amount of carbonyl groups is present in the paper, a strong deacidification can promote an alkali-catalysed ,-alkoxy elimination, leading to the breaking of the anhydroglucose ring in the cellulose chain. In this case, and also in the case of non-acidic but oxidised papers, a reduction treatment is necessary. Because of the high costs of restoration procedures, it is essential to determine whether the reduction treatment is a primary need. In this work we report a study, based on micron-scale space resolved Raman microscopy, infrared reflectance spectroscopy and atomic force microscopy, of differently degraded samples of paper. Non-treated and oxidised samples were investigated, as well as original ancient documents. The aim of this work is to achieve a better understanding of the degradation pattern of historical samples in order to be able to choose the most appropriate restoration treatment using non-destructive spectroscopic techniques. Analysis of the samples demonstrates that degradation processes occur mainly on fibrils and on the fibre wall, as shown also by atomic force microscopy measurements. Copyright © 2006 John Wiley & Sons, Ltd. [source] Role of mineral nutrition in minimizing cadmium accumulation by plantsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2010Nadeem Sarwar Abstract Cadmium (Cd) is a highly toxic heavy metal for both plants and animals. The presence of Cd in agricultural soils is of great concern regarding its entry into the food chain. Cadmium enters into the soil,plant environment mainly through anthropogenic activities. Compounds of Cd are more soluble than other heavy metals, so it is more available and readily taken up by plants and accumulates in different edible plant parts through which it enters the food chain. A number of approaches are being used to minimize the entry of Cd into the food chain. Proper plant nutrition is one of the good strategies to alleviate the damaging effects of Cd on plants and to avoid its entry into the food chain. Plant nutrients play a very important role in developing plant tolerance to Cd toxicity and thus, low Cd accumulation in different plant parts. In this report, the role of some macronutrients (nitrogen, phosphorus, sulfur and calcium), micronutrients (zinc, iron and manganese), and silicon (a beneficial nutrient) has been discussed in detail as to how these nutrients play their role in decreasing Cd uptake and accumulation in crop plants. Copyright © 2010 Society of Chemical Industry [source] Mutations in GPIIIa molecule as a cause for Glanzmann thrombasthenia in Indian patientsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 3 2005S. NAIR Summary.,Background:,Glanzmann thrombasthenia (GT) results from a quantitative or qualitative defect of GPIIb,IIIa complex, the fibrinogen receptor on platelets, which plays a very important role in platelet aggregation. In this report we describe the molecular studies on 22 patients with Glanzmann Thrombasthenia at our institute. Objectives:,The main objective was to identify the mutations present in our GT population in order to establish a strategy for genetic counseling and antenatal diagnosis. Methods:,Twenty-two patients with GT were included in the present study. Complete blood count (CBC), platelet aggregation, flow cytometry, Western blot, single strand conformation polymorphism (SSCP) and denaturing gradient gel electrophoresis (DGGE) were performed in all the patients. The patients showing an abnormal migration pattern in SSCP or DGGE were sequenced further on an automated sequencer. Results:,Of the 22 patients studied, mutations were detected in 12 individuals. Of these, 11 were novel mutations and one mutation Y115C was reported earlier. Flow cytometric analysis showed the absence of receptors in type I GT, highly reduced levels in type II GT and normal levels in type III GT. The DGGE analysis and SSCP analysis of the patients showed different migration patterns. Sequencing was performed in all patients showing an abnormal migration pattern. Of the 22 cases studied mutations could be detected in 12 cases of GT. We could detect six patients with point mutations, four patients with insertions and five patients with deletion mutations. Exon 4 has been found to be the most common site for mutations in our patients. Conclusion:,This study has shown a wide array of mutations present in our GT patients which would be extremely useful in genetic counseling and prenatal diagnosis, essential in preventing these disorders in succeeding generations. [source] Impact of Solar Ultraviolet Radiation on Marine Phytoplankton of Patagonia, Argentina,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2005E. Walter Helbling ABSTRACT Patagonia area is located in close proximity to the Antarctic ozone "hole" and thus receives enhanced ultraviolet B (UV-B) radiation (280,315 nm) in addition to the normal levels of ultraviolet A (UV-A; 315,400 nm) and photosynthetically available radiation (PAR; 400-700 nm). In marine ecosystems of Patagonia, normal ultraviolet radiation (UVR) levels affect phytoplankton assemblages during the three phases of the annual succession: (1) prebloom season (late summer-fall), (2) bloom season (winter-early spring) and (3) postbloom season (late spring-summer). Small-size cells characterize the pre-and postbloom communities, which have a relatively high photosynthetic inhibition because of high UVR levels during those seasons. During the bloom, characterized by micro-plankton diatoms, photosynthetic inhibition is low because of the low UVR levels reaching the earth's surface during winter; this community, however, is more sensitive to UV-B when inhibition is normalized by irradiance (i.e. biological weighting functions). In situ studies have shown that UVR significantly affects not only photosynthesis but also the DNA molecule, but these negative effects are rapidly reduced in the water column because of the differential attenuation of solar radiation. UVR also affects photosynthesis versus irradiance (P vs E) parameters of some natural phytoplankton assemblages (i.e. during the pre- but not during the postbloom season). However, there is a significant temporal variability of P vs E parameters, which are influenced by the nutrient status of cells and taxonomic composition; taxonomic composition is in turn associated with the stratification conditions (e.g. wind speed and duration). In Patagonia, wind speed is one of the most important variables that conditions the development of the winter bloom by regulating the depth of the upper mixed layer (UML) and hence the mean irradiance received by cells. Studies on the interactive effects of UVR and mixing show that responses of phytoplankton vary according to the taxonomic composition and cell structure of assemblages; therefore cells use UVR if >90% of the euphotic zone is being mixed. In fact, cell size plays a very important role when estimating the impact of UVR on phytoplankton, with large cells being more sensitive when determining photosynthesis inhibition, whereas small cells are more sensitive to DNA damage. Finally, in long-term experiments, it was determined that UVR can shape the diatom community structure in some assemblages of coastal waters, but it is virtually unknown how these changes affect the trophody-namics of marine systems. Future studies should consider the combined effects of UVR on both phytoplankton and grazers to establish potential changes in biodiversity of the area. [source] Spirulina platensis protects against gentamicin-induced nephrotoxicity in ratsPHYTOTHERAPY RESEARCH, Issue 11 2008Ali Karadeniz Abstract The present study aimed to investigate the protective effect of Spirulina platensis (SP) on gentamicin sulphate (GS)-induced changes in the levels of lipid peroxidation and endogenous antioxidants in the kidney of rats. Sprague-Dawley rats were treated in separate groups as follows for 7 consecutive days: control (C), gentamicin sulphate (100 mg/kg i.p.) (GS), Spirulina platensis (1000 mg/kg orally) (SP) and Spirulina platensis (1000 mg/kg orally) plus gentamicin sulphate (100 mg/kg i.p.) (SP + GS). The degree of protection was evaluated by determining the effects of Spirulina platensis on malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPX) and nitric oxide (NO), and plasma creatinine and urea levels were estimated in kidney homogenates to evaluate antioxidant activity, and the kidney was histologically examined as well. Spirulina platensis elicited significant nephroprotective activity by decreasing lipid peroxidation (MDA) and elevated the levels of GSH, SOD, GPX, NO, creatinine and urea. Furthermore, these biochemical observations were supplemented by histological examination of the rat kidneys. In conclusion, the present study indicates a very important role of reactive oxygen species (ROS) and the relation to renal dysfunction and point to the therapeutic potential of Spirulina platensis in gentamicin sulphate induced nephrotoxicity. Copyright © 2008 John Wiley & Sons, Ltd. [source] Changes in the strategic management of technology: results of a global benchmarking studyR & D MANAGEMENT, Issue 2 2002Jakob Edler This contribution analyses main changes in the strategic management of technology of the world's most technology-intensive companies from western Europe, North America and Japan. The results presented here are based on a literature review and a survey which show the following main results: first, R&D and technology have become key cornerstones of corporate and business strategy. Second, there is a growing tendency to acquire technology from external sources throughout the sample. Third, internationalization of R&D plays a very important role in the strategies of the large companies investigated and the data shows that it will certainly gain further momentum. However, internationalization of R&D is confined to the Triad regions and is not ,global'. Based on our analysis, cornerstones of a future generation of R&D/technology management are developed. [source] Assessment of hidden and future customer needs in Finnish business-to-business companiesR & D MANAGEMENT, Issue 4 2001Hannu Kärkkäinen The development of new products should be based on the needs expected to exist even several years ahead , at the moment of market introduction and during the whole lifecycle of the product. To develop successful new products in the toughening business environment, companies should be able to surpass customers' expectations and to assess emerging customer needs proactively. Early, thorough understanding of the customer's real needs, including the assessment of hidden and future customer needs and requirements, plays a very important role in the successful development of new products. The purpose of our paper is to study the assessment of new (hidden and future) customer needs for product development in Finnish business-to-business companies. We have carried out a survey in 93 Finnish business-to-business companies and SBUs to study their common problems in the assessment of unrecognized customer needs and potentially effective ways in clarifying new customer needs and dealing with important problems. On the basis of the results, we propose several possible ways to facilitate the assessment of unrecognized customer needs. [source] Electron ionization mass spectral fragmentation of cholestane-3,,4,,5, -triol and cholestane-3,,5,,6,/, -triol bis- and tris-trimethylsilyl derivativesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 14 2005J.-F. Rontani The electron ionization (EI) mass spectral fragmentation of the bis- and tris-trimethylsilyl derivatives of cholestane-3,,4,,5, -triol, cholestane-3,,5,,6, -triol and cholestane-3,,5,,6, -triol was investigated. The EI mass spectrum of the 3,,4, -bis-trimethylsilyl derivative of cholestane-3,,4,,5, -triol exhibits interesting fragment ions at m/z 142 and 332 resulting from the initial loss of TMSOH between the carbons 2 and 3 and subsequent retro-Diels-Alder (RDA) cleavage of the ring A. Trimethylsilyl transfer between the 4, - and the 5, -hydroxy groups acts significantly before RDA cleavage affording an ion at m/z 404. Complete silylation of cholestane-3,,4,,5, -triol strongly stabilizes the molecule, affording an abundant molecular ion at m/z 636 and decreasing the abundance of the RDA cleavage. Loss of water (from the non-silylated 5, -hydroxy group) plays a very important role during the decomposition of the molecular ion of 3,,6,/, -bis-trimethylsilyl derivatives of cholestane-3,,5,,6,/, -triols. These derivatives appear to be very useful in assigning the configuration of the carbon 6. This assignment is based on the abundance of the fragment ions at m/z 321, 367 and 403, which are more prominent in the EI mass spectrum of the , -isomer. In contrast, EI mass spectra of the tris-trimethylsilyl derivatives of cholestane-3,,5,,6, -triol and cholestane-3,,5,,6, -triol differ only slightly and appear to be poorly informative. Copyright © 2005 John Wiley & Sons, Ltd. [source] Increasing throughput and information content for in vitro drug metabolism experiments using ultra-performance liquid chromatography coupled to a quadrupole time-of-flight mass spectrometerRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 6 2005Jose Castro-Perez The field of drug metabolism has been revolutionized by liquid chromatography/mass spectrometry (LC/MS) applications with new technologies such as triple quadrupoles, ion traps and time-of-flight (ToF) instrumentation. Over the years, these developments have often relied on the improvements to the mass spectrometer hardware and software, which has allowed users to benefit from lower levels of detection and ease-of-use. One area in which the development pace has been slower is in high-performance liquid chromatography (HPLC). In the case of metabolite identification, where there are many challenges due to the complex nature of the biological matrices and the diversity of the metabolites produced, there is a need to obtain the most accurate data possible. Reactive or toxic metabolites need to be detected and identified as early as possible in the drug discovery process, in order to reduce the very costly attrition of compounds in late-phase development. High-resolution, exact mass measurement plays a very important role in metabolite identification because it allows the elimination of false positives and the determination of non-trivial metabolites in a much faster throughput environment than any other standard current methodology available to this field. By improving the chromatographic resolution, increased peak capacity can be achieved with a reduction in the number of co-eluting species leading to superior separations. The overall enhancement in the chromatographic resolution and peak capacity is transferred into a net reduction in ion suppression leading to an improvement in the MS sensitivity. To investigate this, a number of in vitro samples were analyzed using an ultra-performance liquid chromatography (UPLC) system, with columns packed with porous 1.7,,m particles, coupled to a hybrid quadrupole time-of-flight (ToF) mass spectrometer. This technique showed very clear examples for fundamental gains in sensitivity, chromatographic resolution and speed of analysis, which are all important factors for the demands of today's HTS in discovery. Copyright © 2005 John Wiley & Sons, Ltd. [source] Quercetin protects hamster spermatogenic cells from oxidative damage induced by diethylstilboestrolANDROLOGIA, Issue 5 2010G. Li Summary Quercetin has been reported to be an efficient antioxidant which protects chicken spermatogonial cells from oxidative damage through increasing intracellular antioxidants and decreasing lipid peroxidation. Exposure to diethylstilboestrol (DES) could cause reproductive damage in males, which is associated with oxidative stress. This study was conducted to investigate the protective effects of quercetin on DES-induced oxidative damage in cultured hamster spermatogenic cells. The cells were treated with different concentrations of DES, and their growth status was observed under inverted microscope. The viability of spermatogenic cells was detected by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT). The contents of superoxide dismutase (SOD) in supernatants and glutathione peroxidase (GSH-Px) in cells were detected with spectrophotography. The results showed that quercetin significantly inhibited the DES-induced damage on spermatogenic cells, with the exception of the low-dose group in which no significant difference was observed. The cell survival rate increased significantly in the middle- and high-dose groups. The contents of SOD and GSH-Px were significantly elevated after medication with quercetin (P < 0.01). It can be concluded that quercetin protects spermatogenic cells against DES-induced oxidative damage through increasing intracellular antioxidants and decreasing lipid peroxidation. Quercetin plays a very important role in ameliorating reproductive toxicity induced by environmental oestrogens. [source] | |||||||||||||||||||||||||