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Fundamental Research (fundamental + research)
Selected AbstractsDopaminergic and non-dopaminergic pharmacological hypotheses for gait disorders in Parkinson's diseaseFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 4 2010David Devos Abstract Gait disorders form one component of the axial disorders observed in Parkinson's disease (PD). Indeed, short steps with a forward-leaning stance are diagnostic criteria for PD in the early stages of the condition. Gait disorders also represent a major source of therapeutic failure in the advanced stages of PD (with the appearance of freezing of gait and falls) because they do not respond optimally to the two hand late-stage therapeutics , levodopa and electrical subthalamic nucleus (STN) stimulation. The late onset of doparesistance in these disorders may be linked to propagation of neurodegeneration to structures directly involved in gait control and to non-dopaminergic neurotransmitter systems. The coeruleus locus (a source of noradrenaline) is rapidly and severely affected, leading to a major motor impact. The pedunculopontine nucleus (PPN) and lateral pontine tegmentum (rich in acetylcholine) are both involved in gait. Degenerative damage to the serotoninergic raphe nuclei appears to be less severe, although serotonin-dopamine interactions are numerous and complex. Lastly, dopaminergic depletion leads to glutamatergic hyperactivity of the efferent pathways from the the STN to the PPN. However, the relationships between the various parkinsonian symptoms (and particularly gait disorders) and these pharmacological targets have yet to be fully elucidated. The goal of this review is to develop the various pathophysiological hypotheses published to date, in order to underpin and justify ongoing fundamental research and clinical trials in this disease area. [source] Diamond Transistor Array for Extracellular Recording From Electrogenic CellsADVANCED FUNCTIONAL MATERIALS, Issue 18 2009Markus Dankerl Abstract The transduction of electric signals from cells to electronic devices is mandatory for medical applications such as neuroprostheses and fundamental research on communication in neuronal networks. Here, the use of diamond with its advantages for biological applications as a new material for biohybrid devices for the detection of cell signals is investigated. Using the surface conductivity of hydrogen-terminated single-crystalline diamond substrates, arrays of solution-gate field-effect transistors were fabricated. The characterization of the transistors reveals a good stability in electrolyte solutions for at least 7 days. On these devices, cardiomyocyte-like HL-1 cells as well as human embryonic kidney cells (HEK293), which were stably transfected with potassium channels, are cultured. Both types of cells show healthy growth and good adhesion to the substrate. The diamond transistors are used to detect electrical signals from both types of cells by recording the extracellular potential. For the HL-1 cells, the shape of action potentials can be resolved and the propagation of the signal across the cell layer is visible. Potassium currents of HEK293 cells are activated with the patch-clamp technique in voltage-clamp mode and simultaneously measured with the field-effect transistors. The ion sensitivity of the diamond surface enables the detection of released potassium ions accumulated in the cleft between transistor and cell. [source] High-Density Carrier Accumulation in ZnO Field-Effect Transistors Gated by Electric Double Layers of Ionic LiquidsADVANCED FUNCTIONAL MATERIALS, Issue 7 2009Hongtao Yuan Abstract Very recently, electric-field-induced superconductivity in an insulator was realized by tuning charge carrier to a high density level (1,×,1014 cm,2). To increase the maximum attainable carrier density for electrostatic tuning of electronic states in semiconductor field-effect transistors is a hot issue but a big challenge. Here, ultrahigh density carrier accumulation is reported, in particular at low temperature, in a ZnO field-effect transistor gated by electric double layers of ionic liquid (IL). This transistor, called an electric double layer transistor (EDLT), is found to exhibit very high transconductance and an ultrahigh carrier density in a fast, reversible, and reproducible manner. The room temperature capacitance of EDLTs is found to be as large as 34,µF cm,2, deduced from Hall-effect measurements, and is mainly responsible for the carrier density modulation in a very wide range. Importantly, the IL dielectric, with a supercooling property, is found to have charge-accumulation capability even at low temperatures, reaching an ultrahigh carrier density of 8×1014 cm,2 at 220,K and maintaining a density of 5.5×1014 cm,2 at 1.8,K. This high carrier density of EDLTs is of great importance not only in practical device applications but also in fundamental research; for example, in the search for novel electronic phenomena, such as superconductivity, in oxide systems. [source] Non-invasive Detection of Cellular Bioelectricity Based on Carbon Nanotube Devices for High-Throughput Drug ScreeningADVANCED MATERIALS, Issue 29 2010Tze-Sian Pui Nanoelectronic biosensors based on readily fabricated networks of single-walled carbon nanotubes (SWNT-net) were used to non-invasively detect cellular bioelectrical signals. This nanotube approach promises applications in both fundamental research and high-throughput drug screening targeting on ion channels. [source] Highly Ordered, Millimeter-Scale, Continuous, Single-Crystalline Graphene Monolayer Formed on Ru (0001)ADVANCED MATERIALS, Issue 27 2009Yi Pan A single-crystalline graphene monolayer is grown on a Ru(0001) surface by thermal annealing of a ruthenium single crystal containing carbon. The layer is highly ordered, continuous, and exhibits perfect crystallinity, with good long-range order on the order of millimeters (see figure). These findings offer high-quality graphene layers for fundamental research as well as large-scale graphene wafers for device fabrication and integration. [source] Glucocorticoid-inducible gene expression vectors for use in Drosophila melanogaster Schneider 2 cellsINSECT MOLECULAR BIOLOGY, Issue 2 2004J. Poels Abstract Inducible, vector-based, expression systems that allow fine control of transgene expression are gaining more and more use in fundamental research as well as in therapeutic applications. In an effort to develop a tightly regulated heterologous expression system for Drosophila Schneider 2 cells, three different inducible reporter constructs were compared. These comprised six copies of the glucocorticoid response element fused to one of three distinct types of Drosophila gene promoters: (1) a TATA-box containing, (2) a TATA-less and (3) a bidirectional core sequence. These were fused to a luciferase reporter gene. The promoter constructs displayed different basal as well as agonist-induced activities. The implications of the observations made are discussed in the context of promoter properties and of induction of genes that may be studied in Drosophila. [source] THE INFLUENCE OF FUNDAMENTALS ON EXCHANGE RATES: FINDINGS FROM ANALYSES OF NEWS EFFECTSJOURNAL OF ECONOMIC SURVEYS, Issue 4 2010Rafael R. Rebitzky Abstract As we survey the literature of macroeconomic news in the foreign exchange market, we can by now look back on nearly 30 years of research. The first studies which analysed news effects on exchange rates were established in the early 1990s (see, for example, Dornbusch). Almost at the same time Meese and Rogoff published their influential paper, revealing the forecasting inferiority in exchange rates of structural models against the random walk. This finding has shocked the pillars of exchange rate economics and thus cast general suspicion on research focusing on fundamentals in this field. The eventual rising popularity of event studies can partly be attributed to the re-establishment of the,raison d'être,of exchange rate economics. This work focuses on systematically surveying this literature with particular respect to its primary goal, i.e. shedding light on the analytical value of fundamental research. Thus, its major findings are, first, fundamental news does matter, whereas non-fundamental news matters to a lesser degree. Second, news influences exchange rates via two separated channels, i.e. incorporating common information into prices directly or indirectly based upon order flow. Third, with a few exceptions the impact of fundamental news on exchange rates is fairly stable over time. [source] Cellulose structure and biosynthesis: What is in store for the 21st century?JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2004R. Malcolm Brown Jr. Abstract This article briefly summarizes historical developments in fundamental research related to the structure and biosynthesis of cellulose. Major advances concerning the structure of cellulose include the discovery of a new suballomorph of cellulose I, the lattice imaging of glucan chains showing no fringe micelle structure, parallel chain orientation in cellulose I, and the discovery of nematic ordered cellulose. Major advances in biosynthesis include the discovery of the terminal synthesizing complex, the isolation and purification of cellulose synthase, the in vitro synthesis of cellulose I, and synthetic cellulose assembly. This article focuses on recent advances in molecular biology with cellulose, including the cloning and sequencing of cellulose synthase genes from bacteria, cyanobacteria, and vascular plants; proof of the terminal synthesizing complex as the site of the catalytic subunit of cellulose synthase; cellulose and callose synthase expression during growth and development; and phylogenetic aspects of cellulose synthase evolution. This article concludes with thoughts about future uses for the accumulating genetic information on cellulose biosynthesis for textiles and forest products and discusses possibilities of new global resources for cellulose production. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 487,495, 2004 [source] Hepatitis C and Alcohol: Fundamental and Translational Research DirectionsALCOHOLISM, Issue 4 2003Timothy R. Morgan The scientific knowledge base that would inform and direct the development of more effective treatment and intervention strategies for these linked pandemics is inadequate. Therefore, the National Institute on Alcohol Abuse and Alcoholism (NIAAA) organized a workshop in which a multidisciplinary group of experts was asked to review the state-of-the-science specific to alcohol in the context of hepatitis C infection. The panel was charged with identifying newly emerging areas likely to lead to advances in fundamental research and to identify those with the greatest potential for accelerating the development of more effective treatment options. The workshop panel made recommendations for research in four major categories: clinical studies of alcohol and HCV; virology and immunology; liver fibrosis and mechanisms of liver injury; and the development of model systems. This article summarizes the panel's deliberations and their recommendations for future research on alcohol and hepatitis C. [source] The Family of GFP-Like Proteins: Structure, Function, Photophysics and Biosensor Applications.PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2006Introduction, Perspective ABSTRACT In this issue, we offer a symposium-in-print that is focused on several new advancements in fundamental research related to the family of GFP (green fluorescent protein)-like proteins. A few applied aspects are also included to illustrate the impact this amazing set of colored proteins has made on our understanding of cell biology at the molecular level. The six articles presented here cut across several disciplines ranging from biological function to protein structure to photophysical aspects. These highly original pieces of work include both experimental and computational approaches, and will provide the reader with significant insight into current, state-of-the-art research activities in this very dynamic and fast-paced field. In the first part of this perspective, I will give a brief overview of the history and salient features of GFPs, cite some examples that illustrate their impact on biotechnology, and provide a brief review of the structural and chemical features that lend these proteins their fascinating appearance. In the second part, I will introduce each of the peer-reviewed contributions of the participating authors. [source] Examples for the integration of self-organized nanowires for functional devices by a fracture approachPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2010Dawit Gedamu Abstract Simple and versatile methods to form nanowires on microchips are of interest for fundamental research and hold the potentials for an industrial fabrication. In this review article, one of these methods based on thin film fracture will be described introducing the experimental parameters and the potential for research. The advantages of the utilization of thin film cracks as a template for the nanowire formation are numerous: nanowire generation ready with contacts, a wide ranging freedom in the choice of materials, influence on the internal structure of the nanowire or the precise positioning on a microchip. A detailed discussion about the fabrication steps and some preliminary experiments revealing the possibilities of the fracture approach will be given for obtained metallic, semiconducting and anodized nanowires. In contrast to their macroscopic counterparts, the conductivity through the nanowires is entirely different. The influence of the surrounding gas atmospheres and the application of electrical fields demonstrate the applicability of these nanowires fabricated by using such a fracture approach. Perspective scanning electron microscopy micrograph of Au nanowires fabricated by thin film fracture approach between Au contact lines. The wires form a zigzag pattern on the thermally oxidized layer substrate on a silicon chip. [source] Preface: phys. stat. sol. (c) 1/6PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2004Alexey Kavokin This volume contains some of the papers presented at the Third International Conference on Physics of Light,Matter Coupling in Nanostructures (PLMCN3) which took place in Acireale, Sicily, from 1 to 4 October 2003. This meeting was fourth in the series started by PLMCN (St. Nectaire, 2000) and continued by PLMCN1 (Rome, 2001) and PLMCN2 (Rithymnon, 2002). All four conferences had the same format (about 70 participants), similar subject scope (interface between fundamental physics of light,matter coupling phenomena and applied research on new semiconductor materials and low-dimensional structures), and the proceedings of all of them have been published in physica status solidi. During these four years, a huge progress has been achieved in the understanding of exciton,polariton effects in microcavities. From the discovery of stimulated scattering of polaritons in 1999 to the first experimental reports of polariton Bose condensation and lasing, attention to this rapidly developing research area has been increased drastically. It is clear now that realization of a new generation of opto-electronic devices, referred to as polariton devices, is a realistic task for the coming decade. To achieve this target, much work has to be done both in fundamental research on dynamics of exciton,polaritons in microcavities and experimental realization of high-quality microcavities presumably based on wide-band gap semiconductors like GaN, ZnO, ZnSe, suitable for the observation of strong exciton,light coupling at room temperature. Forty nine research teams from twelve European countries have created a Polariton Consortium aimed at integration of the European research effort towards fabrication of polariton devices. PLMCN3 was not only an international conference devoted, in particular, to the research on polariton devices, but also the first scientific meeting of this community. The PLMCN meetings since the very first one have been sponsored by the US Army European Research Office (ERO). This time, with the initiative of Jim Harvey from ERO, a special session has been organized on the devices of 21st century, where a number of intriguing ideas have been proposed on new light sources, polariton lasers, and quantum memory elements based on microcavities. A special prize for the most crazy but realizable idea has been won by Misha Portnoi (Exeter) for the concept of a white diode based on a microcavity. Each PLMCN meeting brings participants from new countries. This time, the traditionally strong participation from Japan, Russia, the European Union and the USA has been enforced by a representative delegation from Israel and two speakers from Mexico. We are looking forward for new-comers from other countries not yet involved in the PLMCN community, to join us for the next meeting to be held in St. Petersburg on 29 June,3 July 2004. Sergey Ivanov from the A. F. Ioffe Institute chairs the local Organizing Committee of this future conference. We are going to keep a unique informal and creative atmosphere being characteristic of the PLMCN meetings. We invite all those who wish to know more about light,matter coupling in solids or to present any new interesting results in this area and at the same time to enjoy the beautiful city of St. Petersburg, to contact Sergey Ivanov (ivan@beam.ioffe.rssi.ru) or myself (kavokin@lasmea.univ-bpclermont.fr). We are looking forward to welcoming you in St. Petersburg! [source] Changing views in Canadian geomorphology: are we seeing the landscape for the processes?THE CANADIAN GEOGRAPHER/LE GEOGRAPHE CANADIEN, Issue 3 2010IAN J. WALKER géomorphologie; révolution quantitative; formes du lit marin; éolien; transport des sédiments; dunes Geomorphology in Canada, as elsewhere, has evolved into an essentially bipartite discipline focusing either on ,process' or broader ,historical' (Quaternary) landscape interpretation. A growing emphasis on process-oriented research that relies increasingly on instrumentation and computational technologies has occurred. Critics of such research note limited applicability for landscape evolution, fashionability of methods and limited societal relevance. Indeed, some say we are not seeing the landscape for the processes. This article discusses the changing nature of geomorphology since the Quantitative Revolution of the 1950s including new advances, recent trends and challenges. Publication trends and recent advances suggest that the discipline is very healthy (following a slump in the early 1990s) and continues to evolve, which may reflect increasing research infrastructure and/or funding opportunities and new publications spotlighting Canadian research. Unfortunately, fundamental (less applied) research is threatened by funding program shifts, changing institutional pressures and a decline in research capacity from retirement attrition, and student recruitment challenges. Three research priorities are recommended: (1) continued fundamental research, (2) more integrated modelling to link micro scale processes to macro scale landform behaviour and(3) improvements in profiling our discipline amongst students and related professionals. L'évolution des perspectives de la géomorphologie canadienne : les processus occultent-ils le paysage? Le caractère bipartite que revêt aujourd'hui la géomorphologie au Canada, comme partout ailleurs dans le monde, marque l'aboutissement de l'évolution d'une discipline axée soit sur les «processus», soit sur une interprétation élargie et «historique» (quaternaire) du paysage. De plus en plus, la recherche porte sur les processus et s'inscrit dans le cadre du développement des technologies d'instrumentation et informatique. Plusieurs ont critiqué cette approche de recherche en soulignant ses limites pour étudier l'évolution des paysages, l'effet de mode des méthodes, et la faiblesse de son apport à la société. Certains vont jusqu'à dire que les processus nous cachent la vue du paysage. Cet article traite du caractère évolutif de la géomorphologie depuis les années 1950 quand les bases de la révolution quantitative ont étéétablies. La discussion porte entre autres sur le progrès des connaissances, les dernières tendances et les défis à relever. Les tendances en matière de publication et l'avancement des connaissances laissent croire que la discipline se porte bien (malgré un ralentissement au début des années 1990) et suit une trajectoire évolutive. Il est possible qu'une telle situation soit le reflet del'accroissement des capacités de recherche et/ou du financement et des nouvelles publications mettant en évidence les résultats de recherches canadiennes. Malheureusement, les modifications apportées aux programmes de subvention, les différentes pressions exercées par les institutions, la baisse de régime en matière de recherche causée par les départs à la retraite, et les défis pour assurer la relève universitaire constituent une menace pour la recherche fondamentale (c'est-à-dire moins appliquée). C'est dans cette foulée que trois chantiers de recherche sont proposés : (1) poursuivre la recherche fondamentale, (2) élaborer des modèles plus intégrés qui conjuguent les processus à l'échelle micro et les comportements des formes de relief, et (3) procéder à des améliorations du profilage des étudiants et des professionnels apparentés. [source] Extent and possible conservation implications of fish use for research, testing and education in North AmericaAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 6 2006Melissa Grey Abstract 1.Fish species are used globally for fundamental research, product and environmental testing, and education, but this use has not hitherto been documented. The number of fish used for research and education in North America currently represents approximately one-quarter of all animal use for these purposes; only mice are used in higher numbers. Data from the Canadian Council on Animal Care, various animal care committees from Canadian universities, and the United States Fish and Wildlife Service are collated and summarized. 2.In Canada nearly a half a million fish were used for research and education each year from 1996 to 2001. We estimated that the United States used over four times that amount for the same purposes, totalling approximately 2.8 million fish each year. 3.At least 100 fish species, representing 27 taxonomic orders, were used for research and education in North America from 1996 to 2001. Close to one-third of the species had life-history characteristics that might make them particularly susceptible to over-exploitation. This potential vulnerability, coupled with data from animal care facilities in Canada suggesting that nearly half of all fish used for research and education were wild-caught, should prompt further documentation of such fish uses in order to assess their sustainability. Copyright © 2006 John Wiley & Sons, Ltd. [source] Managing grapevines to optimise fruit development in a challenging environment: a climate change primer for viticulturistsAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2010M. KELLER Abstract Grapevine reproductive development extends over two seasons, and the genotypic expression of yield potential and fruit composition is subject to environmental impacts, which include viticultural manipulations, throughout this period. This paper reviews current knowledge on yield formation and fruit composition and attempts to identify challenges, opportunities and priorities for research and practice. The present analysis of published information gives a critical appraisal of recent advances concerning variables, especially as they relate to global climate change, that influence yield formation and fruit composition at harvest. Exciting discoveries in fundamental research on the one hand and an increasing focus on outcomes and knowledge transfer on the other are enabling the development and implementation of practical recommendations that will impact grape production in the future. Future research should aim to minimise seasonal variation and optimise the profitable and sustainable production of high-quality fruit for specific uses in the face of climate change, water and labour shortages, shifting consumer preferences and global competition. Better control of product quantity and quality, and differentiation to meet consumer demands and market preferences will enhance the competitiveness and sustainability of the global grape and wine industries. [source] Online Particle Size Measurement in Microgel Particle Suspensions: Principles and Data AnalysisCHEMIE-INGENIEUR-TECHNIK (CIT), Issue 10 2010Prof. Dr.-Ing. Abstract If a gelled system is subjected to shearing or the concentration of reactive components is low, microgel particles are formed. Since labile microgel particles with high water capacities can often be found in food systems, and as they are important for the textural properties, particle size measurement is relevant for fundamental research and control of industrial processes. A chord length measurement system was tested for online particle sizing. [source] Membranen für Polymerelektrolyt-Brennstoffzellen,CHEMIE-INGENIEUR-TECHNIK (CIT), Issue 11 2003A. Glüsen Dr. rer. nat. Abstract Die Polymerelektrolyt-Membran ist das Herzstück von wasserstoffbetriebenen Polymerelektrolyt-Brennstoffzellen (PEFC) und methanolbetriebenen Direktmethanol-Brennstoffzellen (DMFC). Membranen aus sulfonierten Fluoropolymeren sind derzeit kommerziell erhältlich. Wichtige Forschungs- und Entwicklungsziele sind derzeit für die PEFC die Erhöhung der Betriebstemperatur, ohne die Membran zusätzlich befeuchten zu müssen, und für die DMFC die Verringerung des Methanoltransportes durch die Membran. Zusätzlich sollen durch die Verwendung fluorfreier Polymere die Kosten der Membran und die Umweltbelastung reduziert werden. Dabei spielen bereits in der industriellen Entwicklung befindliche Membranen ebenso eine Rolle wie neue Membrankonzepte aus der Grundlagenforschung. Membranes for Polymer Electrolyte Fuel Cells The polymer electrolyte membrane is the heart of hydrogen fuelled Polymer Electrolyte Fuel Cells (PEFC) and methanol fuelled Direct Methanol Fuel Cells (DMFC). Membranes of sulfonated fluoropolymers are already commercially available. Important goals for research and development are for PEFCs an increased operating temperature without the need for additional humidification and for DMFC the reduction of methanol transport through the membrane. The use of non-fluorinated polymers aims at a reduction in membrane cost and environmental hazards. Membranes already in industrial product development are considered as well as novel membrane concepts in fundamental research. [source] | ||||||||||||||||||||||