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One System (one + system)
Selected AbstractsState of Research in High-consequence Hospital Surge CapacityACADEMIC EMERGENCY MEDICINE, Issue 11 2006Carl H. Schultz MD High-consequence surge research involves a systems approach that includes elements such as healthcare facilities, out-of-hospital systems, mortuary services, public health, and sheltering. This article focuses on one aspect of this research, hospital surge capacity, and discusses a definition for such capacity, its components, and future considerations. While conceptual definitions of surge capacity exist, evidence-based practical guidelines for hospitals require enhancement. The Health Resources and Services Administration's (HRSA) definition and benchmarks are extrapolated from those of other countries and rely mainly on trauma data. The most significant part of the HRSA target, the need to care for 500 victims stricken with an infectious disease per one million population in 24 hours, was not developed using a biological model. If HRSA's recommendation is applied to a sample metropolitan area such as Orange County, California, this translates to a goal of expanding hospital capacity by 20%,25% in the first 24 hours. Literature supporting this target is largely consensus based or anecdotal. There are no current objective measures defining hospital surge capacity. The literature identifying the components of surge capacity is fairly consistent and lists them as personnel, supplies and equipment, facilities, and a management system. Studies identifying strategies for hospitals to enhance these components and estimates of how long it will take are lacking. One system for augmenting hospital staff, the Emergency System for Advance Registration of Volunteer Health Professionals, is a consensus-derived plan that has never been tested. Future challenges include developing strategies to handle the two different types of high-consequence surge events: 1) a focal, time-limited event (such as an earthquake) where outside resources exist and can be mobilized to assist those in need and 2) a widespread, prolonged event (such as pandemic influenza) where all resources will be in use and rationing or triage is needed. [source] Biological warfare in the garden pond: tadpoles suppress the growth of mosquito larvaeECOLOGICAL ENTOMOLOGY, Issue 1 2003Allie Mokany Abstract. 1. Although tadpoles and mosquito larvae may compete for scarce resources in natural freshwater systems, the mechanisms involved in such competition remain largely unstudied. 2. Replicated artificial ponds were set up to examine the role of pathogenic interference (water-borne growth inhibitors) in two tadpole,mosquito systems from south-eastern Australia. One system comprised taxa that are commonly sympatric in freshwater ponds (tadpoles of Limnodynastes peronii and larvae of Culex quinquefasciatus) while the other comprised species that co-occur in brackish water ponds (tadpoles of Crinia signifera and larvae of Ochlerotatus australis). 3. Water that had previously contained tadpoles suppressed the rates of survival and pupation of mosquito larvae in both systems. Fungicide reduced or eliminated this effect, suggesting that the growth inhibitors may be fungal organisms (possibly the yeast Rhodotorula glutinis) from tadpole faeces. Fungicide also enhanced growth rates of tadpoles. 4. These results suggest that interference competition between tadpoles and mosquito larvae is mediated by other organisms in some ecological systems. [source] The ability of two different Vibrio spp. bacteriophages to infect Vibrio harveyi, Vibrio cholerae and Vibrio mimicusJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2004M. Payne Abstract Aims:, To determine the host range of the Vibrio harveyi myovirus-like bacteriophage (VHML) and the cholera toxin conversion bacteriophage (CTX ,) within a range of Vibrio cholerae and V. mimicus and V. harveyi, V. cholerae and V. mimicus isolates respectively. Methods and Results:, Three V. harveyi, eight V. cholerae and five V. mimicus isolates were incubated with VHML and CTX ,. Polymerase chain reaction (PCR) was used to determine the presence of VHML and CTX , in infected isolates. We demonstrated that it was possible to infect one isolate of V. cholerae (isolate ACM #2773/ATCC #14035) with VHML. This isolate successfully incorporated VHML into its genome as evident by positive PCR amplification of the sequence coding part of the tail sheath of VHML. Attempts to infect all other V. cholerae and V. mimicus isolates with VHML were unsuccessful. Attempts to infect V. cholerae non-01, V. harveyi andV. mimicus isolates with CTX , were unsuccessful. Conclusions:, Bacteriophage infection is limited by bacteriophage-exclusion systems operating within bacterial strains and these systems appear to be highly selective. One system may allow the co-existence of one bacteriophage while excluding another. VHML appears to have a narrow host range which may be related to a common receptor protein in such strains. The lack of the vibrio pathogenicity island bacteriophage (VPI ,) in the isolates used in this study may explain why infections with CTX , were unsuccessful. Significance and Impact of the Study:, The current study has demonstrated that Vibrio spp. bacteriophages may infect other Vibrio spp. [source] ESR studies of gas adsorption on carbon nanotubesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 13 2006Catherine F. M. Clewett Abstract The effect of gas adsorption on different carbon nanotube systems is studied using ESR spectrosocpy. One system consists of purified and unpurified single-walled carbon nanotubes, one of unpurified multi-walled tubes, and one of multi-walled tubes where defects have been introduced purposefully at different levels. In single- and multi-walled tubes, hydrogen adsorbs preferentially on defects. Electron-donating ammonia seems to affect the interlayer interaction in multi-walled carbon nanotubes. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Nanosecond pulsed electric field generators for the study of subcellular effectsBIOELECTROMAGNETICS, Issue 3 2006Juergen F. Kolb Abstract Modeling and experimental studies have shown that pulsed electric fields of nanosecond duration and megavolt per meter amplitude affect subcellular structures but do not lead to the formation of large pores in the outer membrane. This "intracellular electromanipulation" requires the use of pulse generators which provide extremely high power but low energy pulses. In this study, we describe the concept of the required pulsed power sources, their design, operation, and the necessary diagnostics. Two types of pulse generators based on the Blumlein line principle have been developed and are described here. One system is designed to treat a large number of cells in cuvettes holding volumes from 0.1 to 0.8 ml. Pulses of up to 40 kV amplitude, with a duration of 10 ns and a rise time close to 1 ns can be applied to the cuvette. For an electrode gap of 1 mm this voltage corresponds to an average electric field of 40 MV/m. The second system allows for real time observation of individual cells under a microscope. It generates pulses of 10,300 ns duration with a rise time of 3.5 ns and voltage amplitudes up to 1 kV. Connected to a microreactor with an electrode gap of 100 µm, electric fields up to 10 MV/m are applied. Bioelectromagnetics 27:172,187, 2006. © 2005 Wiley-Liss, Inc. [source] Integrating Web-Based Documents, Shared Knowledge Bases, and Information Retrieval for User HelpCOMPUTATIONAL INTELLIGENCE, Issue 1 2000Doug Skuce We describe a prototype system, IKARUS, with which we investigated the potential of integrating web-based documents, shared knowledge bases, and information retrieval for improving knowledge storage and retrieval. As an example, we discuss how to implement both a user manual and an online help system as one system. The following technologies are combined: a web-based design, a frame-based knowledge engine, use of an advanced full-text search engine, and simple techniques to control terminology. We have combined graphical browsing with several unusual forms of text retrieval,for example, to the sentence and paragraph level. [source] Immersive Integration of Physical and Virtual EnvironmentsCOMPUTER GRAPHICS FORUM, Issue 3 2004Henry Fuchs We envision future work and play environments in which the user's computing interface is more closely integrated with the physical surroundings than today's conventional computer display screens and keyboards. We are working toward realizable versions of such environments, in which multiple video projectors and digital cameras enable every visible surface to be both measured in 3D and used for display. If the 3D surface positions were transmitted to a distant location, they may also enable distant collaborations to become more like working in adjacent offices connected by large windows. With collaborators at the University of Pennsylvania, Brown University, Advanced Network and Services, and the Pittsburgh Supercomputing Center, we at Chapel Hill have been working to bring these ideas to reality. In one system, depth maps are calculated from streams of video images and the resulting 3D surface points are displayed to the user in head-tracked stereo. Among the applications we are pursuing for this tele-presence technology, is advanced training for trauma surgeons by immersive replay of recorded procedures. Other applications display onto physical objects, to allow more natural interaction with them "painting" a dollhouse, for example. More generally, we hope to demonstrate that the principal interface of a future computing environment need not be limited to a screen the size of one or two sheets of paper. Just as a useful physical environment is all around us, so too can the increasingly ubiquitous computing environment be all around us -integrated seamlessly with our physical surroundings. [source] Analysis of the current methods used to size a wind/hydrogen/fuel cell-integrated system: A new perspectiveINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 12 2010H. G. Geovanni Abstract As an alternative to the production and storage of intermittent renewable energy sources, it has been suggested that one can combine several renewable energy technologies in one system, known as integrated or hybrid system, that integrate wind technology with hydrogen production unit and fuel cells. This work assesses the various methods used in sizing such systems. Most of the published papers relate the use of simulation tools such as HOMER, HYBRID2 and TRNSYS, to simulate the operation of different configurations for a given application in order to select the best economic option. But, with these methods one may not accurately determine certain characteristics of the energy resources available on a particular site, the profiles of estimated consumption and the demand for hydrogen, among other factors, which will be the optimal parameters of each subsystem. For example, velocity design, power required for the wind turbine, power required for the fuel cell and electrolyzer and the storage capacity needed for the system. Moreover, usually one makes excessive use of bi-parametric Weibull distribution function to approximate the histogram of the observed wind to the theoretical, which is not appropriate when there are bimodal frequency distributions of wind, as is the case in several places in the world. A new perspective is addressed in this paper, based on general system theory, modeling and simulation with a systematic approach and the use of exergoeconomic analysis. There are some general ideas on the advantages offered in this method, which is meant for the implementation of wind/hydrogen/fuel cell-integrated systems and in-situ clean hydrogen production. Copyright © 2009 John Wiley & Sons, Ltd. [source] Design aspects of satellite,cellular hybrid wireless systemsINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 2 2002Tamer ElBatt Abstract In this paper we investigate various issues related to the design of satellite,cellular hybrid systems. First, we review the fundamental problems of channel partitioning and call admission/assignment. Second, we study the impact of different frequency reuse constraints, in both layers, on the optimum channel partitioning. Third, we investigate, analytically and via simulation, the effect of reducing the cell size. We emphasize the blocking-forced termination probabilities trade-off for pure cellular and satellite,cellular hybrid systems. Accordingly, an optimization problem with respect to the cell size is formulated. Finally, we search for the optimum dynamic call re-assignment policy that improves the system capacity at the expense of the complexity associated with tearing down a connection in one system and setting-up an alternative one in the other system. For a small hybrid system, we characterized the optimum re-assignment policies that minimize the blocking probability, dropping probability, and a weighted cost function of these probabilities. Copyright © 2002 John Wiley & Sons, Ltd. [source] Effect of thermochemical sludge pretreatment on sludge reduction and on performances of anoxic-aerobic membrane bioreactor treating low strength domestic wastewaterJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2009Khac-Uan Do Abstract BACKGROUND: Reduction of excess sludge production has become an urgent issue. An investigation into the influence of thermochemical sludge pretreatment on sludge reduction in a bench-scale anoxic-aerobic membrane bioreactor was performed. Two systems were operated. In one system, part of the mixed liquid (1.5% of the influent flow rate) was pretreated thermochemically (at 80 °C, pH 11 and 3 h) and returned to the bioreactor. This study examined and evaluated the effect of thermochemical sludge pretreatment on the reduction of excess sludge and on the performance of the system. RESULTS: The average solubilization efficiency of the pretreated sludge was found to be about 0.2. The sludge production rate of the experimental system (E-MBR) was less than that of the control (C-MBR) by about 33%. The total phosphorus was removed mainly by normal cell synthesis, with removal efficiencies of 38,40% and 40,42% for the E-MBR and C-MBR, respectively. The total nitrogen removal in the E-MBR was slightly higher than in the C-MBR due to supply of soluble chemical oxygen demand (SCOD) from the digested sludge solution as an external carbon source. The mixed liquor volatile suspended solids (MLVSS) and mixed liquor suspended solids (MLSS) ratios for the two systems were almost identical, in the range 74,77%, indicating that the inorganics from the disintegrated cells do not accumulate as particulates in the reactor. The TMP was maintained at less than 6 cmHg for 180 days without membrane cleaning. CONCLUSION: Thermochemical sludge pretreatment can play an important role in reducing sludge production. The qualities of the effluent water were not significantly affected during 6 months of operation. Copyright © 2009 Society of Chemical Industry [source] OPTIMAL MANAGEMENT OF CHRONIC HEART FAILURE IN PATIENTS WITH CHRONIC KIDNEY DISEASEJOURNAL OF RENAL CARE, Issue 1 2009Donah Zachariah SUMMARY Chronic kidney disease and chronic heart failure are closely interlinked; an abnormality in one system adversely impacts upon the function of the other. Despite the wealth of evidence available for beneficial treatment strategies in chronic heart failure, the prognosis remains poor and optimum therapy under-utilised. The applicability of proven therapies to patients with co-morbidity remains a particular challenge, especially since marked renal impairment has often been an exclusion criteria in major studies. In this article we discuss the epidemiology and pathophysiology of the two conditions and then focus on the aspects of treatment most pertinent to those patients with heart failure patients and concomitant chronic kidney disease. [source] Upgrade of the CATS sample changer on FIP-BM30A at the ESRF: towards a commercialized standardJOURNAL OF SYNCHROTRON RADIATION, Issue 1 2009L. Jacquamet An upgraded version of the sample changer `CATS' (Cryogenic Automated Transfer System) that was developed on the FIP-BM30A beamline at the ESRF is presented. At present, CATS is installed at SLS (three systems), BESSY (one system), DLS (two systems) and APS (four systems for the LSCAT beamline). It consists mainly of an automated Dewar with an assortment of specific grippers designed to obtain a fast and reliable mounting/dismounting rate without jeopardizing the flexibility of the system. The upgraded system has the ability to manage any sample standard stored in any kind of puck. [source] Exchange of conserved quantities, shock loci and Riemann problemsMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 13 2001Michael Sever Systems of conservation laws admitting extensions, such as entropy density/flux functions, generate related systems obtained by exchanging the extension with one of the constituent equations. Often if not always, the smooth solutions of the two systems coincide, and weak solutions of one system containing only small discontinuities are approximate weak solutions of the other. The adiabatic approximation for the Euler system illustrates the utility of this procedure. Such an exchange of conserved quantities preserves hyperbolicity and genuine non-linearity in the sense of Lax. On the other hand, the topological structure of the shock locus of a point in phase space and the solvability of Riemann problems in the large can be strongly affected. A discussion of when and how this occurs is given here. In this paper the exchange of conserved quantities is conveniently described by a simple homotopy in an extended version of the usual ,symmetric variables'. A dynamical system in phase space is constructed, the trajectories of which describe the Hugoniot locus of a fixed point in phase space at each state of the homotopy. The appearance of critical points for this dynamical system is identified with the alteration of the topological structure of the Hugoniot locus by the exchange of conserved quantities. Copyright © 2001 John Wiley & Sons, Ltd. [source] How do membrane proteins sense water stress?MOLECULAR MICROBIOLOGY, Issue 4 2002Bert Poolman Summary Maintenance of cell turgor is a prerequisite for almost any form of life as it provides a mechanical force for the expansion of the cell envelope. As changes in extracellular osmolality will have similar physicochemical effects on cells from all biological kingdoms, the responses to osmotic stress may be alike in all organisms. The primary response of bacteria to osmotic upshifts involves the activation of transporters, to effect the rapid accumulation of osmo-protectants, and sensor kinases, to increase the transport and/or biosynthetic capacity for these solutes. Upon osmotic downshift, the excess of cytoplasmic solutes is released via mechanosensitive channel proteins. A number of breakthroughs in the last one or two years have led to tremendous advances in our understanding of the molecular mechanisms of osmosensing in bacteria. The possible mechanisms of osmosensing, and the actual evidence for a particular mechanism, are presented for well studied, osmoregulated transport systems, sensor kinases and mechanosensitive channel proteins. The emerging picture is that intracellular ionic solutes (or ionic strength) serve as a signal for the activation of the upshift-activated transporters and sensor kinases. For at least one system, there is strong evidence that the signal is transduced to the protein complex via alterations in the protein,lipid interactions rather than direct sensing of ion concentration or ionic strength by the proteins. The osmotic downshift-activated mechanosensitive channels, on the other hand, sense tension in the membrane but other factors such as hydration state of the protein may affect the equilibrium between open and closed states of the proteins. [source] Agroecosystem modeling and optimal economic decisions: Implications for sustainable agricultureOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 1 2008Craig A. Bond Abstract We adapt a biogeochemical model of an agroecosystem to account for optimal economic behavior on the part of agricultural producers. Two institutional management regimes are considered: one in which a representative producer does not account for stock pollution caused by use of agricultural inputs, and one in which the externality is internalized. Comparative statics of the steady state of the former problem are analyzed in order to gain insight into the effects of potential policy and technological changes. Results show that a more realistic ecosystem component that includes nutrient cycling can qualitatively change optimal management practices relative to a one-state representation, potentially rendering systems ,unsustainable' under some criteria and leading to policy instruments that exacerbate, rather than mitigate, external damages or the resource base. Moreover, the qualitative effect of changes in model parameters are not necessarily uniform across different agricultural systems, implying that a prescription for the so-called ,sustainable' management under one system may have unintended consequences under another system. Copyright © 2007 John Wiley & Sons, Ltd. [source] In situ kinetic modelling of intestinal efflux in rats: functional characterization of segmental differences and correlation with in vitro resultsBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 5 2007Isabel González-Alvarez Abstract The objective was to devise and apply a novel modelling approach to combine segmental in situ rat perfusion data and in vitro cell culture data, in order to elucidate the contribution of efflux in drug absorption kinetics. The fluoroquinolone CNV97100 was used as a model P-gp substrate. In situ intestinal perfusion was performed in rat duodenum, jejunum, ileum and colon to measure the influence of P-gp expression on efflux. Inhibition studies of CNV97100 were performed in the presence of verapamil, quinidine, cyclosporin A and p -aminohippuric acid. Absorption/efflux parameters were modelled simultaneously, using data from both in situ studies as well as in vitro studies. The maximal efflux velocity was modelled as a baseline value, corrected for each segment based on the expression level. CNV97100 passive diffusional permeability (Pdiff) and its affinity for the efflux carrier (Km) were assumed to be the same in all segments. The results indicate the new approach to combine in situ data and in vitro data succeed in yielding a unified, quantitative model for absorption/efflux. The model incorporated a quantitative relationship between P-gp expression level and the efflux functionality, both across in situ and in vitro systems, as well across different intestinal segments in the in situ studies. Permeability values decreased from duodenum to ileum in accordance with the increasing P-gp expression levels in rat intestine. The developed model reflects a strong correlation between in vitro and in situ results, including intrinsic differences in surface area. The successful application of a model approach to combine absorption data from two different experimental systems holds promise for future efforts to predict absorption results from one system to a second system. Copyright © 2007 John Wiley & Sons, Ltd. [source] Control of Biocatalytic Transformations by Programmed DNA AssembliesCHEMISTRY - A EUROPEAN JOURNAL, Issue 12 2010Ronit Freeman Abstract This study demonstrates the self-assembly of inhibitor/enzyme-tethered nucleic acid fragments or enzyme I-, enzyme II-modified nucleic acids into functional nanostructures that lead to the controlled inhibition of the enzyme or the activation of an enzyme cascade. In one system, the anti-cocaine aptamer subunits are modified with monocarboxy methylene blue (MB+) as the inhibitor and with choline oxidase (ChOx). The cocaine-induced self-assembly of the aptamer subunits complex results in the inhibition of ChOx by MB+. In a further configuration, two nucleic acids of limited complementarity are functionalized at their 3, and 5, ends with glucose oxidase (GOx) and horseradish peroxidase (HRP), respectively, or with MB+ and ChOx. In the presence of a target DNA sequence, synergistic complementary base-pairing occurs, thus leading to stable supramolecular Y-shaped nanostructures of the nucleic acid units. A GOx/HRP bienzyme cascade or the programmed inhibition of ChOx by MB+ is demonstrated in the resulting nucleic acid nanostructures. A quantitative theoretical model that describes the nucleic acid assemblies and that results in the inhibition of ChOx by MB+ or in the activation of the GOx/HRP cascade, respectively, is provided. [source] | ||||||||||||||||||||||