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Unifying Concepts (unifying + concept)
Selected AbstractsUNIFYING CONCEPTS IN TEACHING OPTICAL METHODSEXPERIMENTAL TECHNIQUES, Issue 2 2002G. Cloud First page of article [source] The immunocompromised district: a unifying concept for lymphoedematous, herpes-infected and otherwise damaged sitesJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 12 2009V Ruocco Abstract Systemic immunodeficiency is known to facilitate the onset of opportunistic infections, tumours and immune disorders in any district of the body. There are clinical events, such as chronic lymphoedema, herpetic infections, vaccinations and heterogeneous physical injuries which can selectively damage and immunologically mark the cutaneous district they act upon. After the causing event has disappeared, the affected district may appear clinically normal, but its immune behaviour is often compromised forever. An immunocompromised district becomes a site which is particularly susceptible to subsequent outbreaks of opportunistic infections, tumours and immune disorders confined to the district itself. In this review, there is an ample case-report collection of opportunistic disorders (infectious, neoplastic, immune) which appeared in immunocompromised districts. The cases have been grouped according to the clinical settings responsible for the local immune imbalance: regional chronic lymphoedema; herpes-infected sites, which feature the well-known Wolf's isotopic response; and otherwise damaged areas, comprising sites of vaccination, ionizing or UV radiation, thermal burns and traumas. Whatever the immunocompromising factor, a common denominator which facilitates the occurrence of tumours, infections and dysimmune reactions in an immunocompromised district may reside in locally hampered lymph drainage and/or locally altered neuromediator signalling. In fact, any obstacle to the normal trafficking of immunocompetent cells through lymphatic channels or any interference with the signals that the neuropeptides and neurotransmitters released by peripheral nerves send to cell membrane receptors of immunocompetent cells, can significantly alter the local immune response, thus paving the way for heterogeneous opportunistic disorders in the immunocompromised district. [source] Lactate efflux and the neuroenergetic basis of brain functionNMR IN BIOMEDICINE, Issue 7-8 2001Robert G. Shulman Abstract In the unstimulated brain energy is primarily supplied by the oxidation of glucose. However the oxygen-to-glucose index (OGI), which is the ratio of metabolic rates of oxygen to glucose, CMRO2/CMRglc, diverges from the theoretical value of 6 as activity is increased. In vivo measurements of brain lactate show its concentration to increase with stimulation. The decreasing OGI with stimulation had led to the suggestion that activation, unlike resting activity, is supported by anaerobic glycolysis. To date a unifying concept that accommodates glucose oxidation at rest with lactate generation and OGI decrease during stimulation of brain is lacking. Furthermore, energetics that change with increasing activity are not consistent with a neuroenergetic model that has been proposed from 1- 13C-glucose MRS experiments. That model, based upon in vivo MRS measurements and cellular studies by Pellerin and Magistretti, showed that glutamate neurotransmitter cycling was coupled to glucose oxidation over a wide range of brain activities from rest down to deep anesthesia. Here we reconcile these paradoxical observations by suggesting that anaerobic glucose consumption (which can provide energy rapidly) increases with activation to meet the power requirements of millisecond neuronal firing. It is proposed, in accord with our neuroenergetic model, that the extra glucose mobilized rapidly for glial clearance of glutamate, is not needed for the oxidative processes that are responsible for neuronal firing and glutamate release, and consequently it is effluxed as lactate. A stoichiometric relation between OGI and lactate concentration is derived from the neuroenergetic model, showing that the enhanced glucose uptake during activation is consistent with neuronal activity being energetically supported by glucose oxidation. Copyright © 2001 John Wiley & Sons, Ltd. [source] `Making the molecular movie': first framesACTA CRYSTALLOGRAPHICA SECTION A, Issue 2 2010R. J. Dwayne Miller Recent advances in high-intensity electron and X-ray pulsed sources now make it possible to directly observe atomic motions as they occur in barrier-crossing processes. These rare events require the structural dynamics to be triggered by femtosecond excitation pulses that prepare the system above the barrier or access new potential energy surfaces that drive the structural changes. In general, the sampling process modifies the system such that the structural probes should ideally have sufficient intensity to fully resolve structures near the single-shot limit for a given time point. New developments in both source intensity and temporal characterization of the pulsed sampling mode have made it possible to make so-called `molecular movies', i.e. measure relative atomic motions faster than collisions can blur information on correlations. Strongly driven phase transitions from thermally propagated melting to optically modified potential energy surfaces leading to ballistic phase transitions and bond stiffening are given as examples of the new insights that can be gained from an atomic level perspective of structural dynamics. The most important impact will likely be made in the fields of chemistry and biology where the central unifying concept of the transition state will come under direct observation and enable a reduction of high-dimensional complex reaction surfaces to the key reactive modes, as long mastered by Mother Nature. [source] Understanding fish habitat ecology to achieve conservation,JOURNAL OF FISH BIOLOGY, Issue 2005J. C. Rice Habitat science can provide the unifying concepts to bring together ecological studies of physiological tolerances, predator avoidance, foraging and feeding, reproduction and life histories. Its unifying role is built on two assumptions, imported from terrestrial habitat science and not always stated explicitly: that competition is present interspecifically and intraspecifically under at least some conditions, and that habitat features have some persistence and predictability in space and time. Consistent with its central conceptual position in ecology, habitat science has contributed importantly to scientific advice on pollution, coastal zone management and many other areas of environmental quality, although it has been largely divorced from developments in fish populations dynamics done in support of fisheries management. Commitments by most management agencies to apply an integrated, ecosystem approach to management of human activities in marine systems, poses new challenges to marine science advisors to management. Integrated management and ecosystem approaches both inherently require spatial thinking and spatial tools, making habitat science a particularly relevant advisory framework, particularly because of the unifying role of habitat in ecology. The basic mechanisms behind ocean biological dynamics, productivity, concentration and retention, however, present much weaker opportunities for competition and less persistence and predictability, weakening the foundations of theory and concepts behind current habitat science. The paper highlights the new types of thinking about ,habitat' that will be required, if habitat science is to meet the advisory needs of the new approaches to management. [source] Principles in quality assurance.QUALITY ASSURANCE JOURNAL, Issue 4 2002Part 1. Abstract The regulated pharmaceutical industry is an ocean of complexity and detail through which Quality Assurance (QA) professionals must steer the best course, playing a crucial role in the profitability of the industry and the well-being of patients. How best to keep the 'good ship' QA stable and effective while being battered by the numerous changing priorities, last-minute demands, or unforeseen events, is a challenge to us all, and the subject of this paper. The ideas presented here are simple, perhaps simplistic, and stem from the idea that, in order to be effective in this complex environment, we have to find some fundamental unifying concepts that can be applied consistently to our work. Semantics aside, we will consider these unifying concepts to be 'principles' and this paper will describe their definition and application within a bioanalytical Contract Research Organization (CRO). Copyright © 2002 John Wiley & Sons, Ltd. [source] The Analogy between Light and Sound in the History of Optics from the ancient Greeks to Isaac Newton.CENTAURUS, Issue 3 2010Part Analogies between hearing and seeing already existed in ancient Greek theories of perception. The present paper follows the evolution of such analogies until the rise of 17th century optics, with due regard to the diversity of their origins and nature but with particular emphasis on their bearing on the physical concepts of light and sound. Whereas the old Greek analogies were only side effects of the unifying concepts of perception, the analogies of the 17th century played an important role in constructing optical theories by imitation of acoustic theories, or vice versa. This transition depended on several factors including the changing relations between optics, music, mathematics, and physics, the diversity of early modern concepts of sound, and the rise of a new physics based on experimentation and mechanical explanation. [source] The Analogy between Light and Sound in the History of Optics from the Ancient Greeks to Isaac Newton.CENTAURUS, Issue 2 2010Part Analogies between hearing and seeing already existed in ancient Greek theories of perception. The present paper follows the evolution of such analogies until the rise of 17th century optics, with due regard to the diversity of their origins and nature but with particular emphasis on their bearing on the physical concepts of light and sound. Whereas the old Greek analogies were only side effects of the unifying concepts of perception, the analogies of the 17th century played an important role in constructing optical theories by imitation of acoustic theories, or vice versa. This transition depended on several factors including the changing relations between optics, music, mathematics, and physics, the diversity of early modern concepts of sound, and the rise of a new physics based on experimentation and mechanical explanation. [source] The Mechanism of Water Oxidation: From Electrolysis via Homogeneous to Biological CatalysisCHEMCATCHEM, Issue 7 2010Holger Dau Prof. Abstract Striving for new solar fuels, the water oxidation reaction currently is considered to be a bottleneck, hampering progress in the development of applicable technologies for the conversion of light into storable fuels. This review compares and unifies viewpoints on water oxidation from various fields of catalysis research. The first part deals with the thermodynamic efficiency and mechanisms of electrochemical water splitting by metal oxides on electrode surfaces, explaining the recent concept of the potential-determining step. Subsequently, novel cobalt oxide-based catalysts for heterogeneous (electro)catalysis are discussed. These may share structural and functional properties with surface oxides, multinuclear molecular catalysts and the catalytic manganese,calcium complex of photosynthetic water oxidation. Recent developments in homogeneous water-oxidation catalysis are outlined with a focus on the discovery of mononuclear ruthenium (and non-ruthenium) complexes that efficiently mediate O2 evolution from water. Water oxidation in photosynthesis is the subject of a concise presentation of structure and function of the natural paragon,the manganese,calcium complex in photosystem,II,for which ideas concerning redox-potential leveling, proton removal, and OO bond formation mechanisms are discussed. The last part highlights common themes and unifying concepts. [source] | |||||||||||||