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Increased Efficiency (increased + efficiency)
Selected AbstractsChemoenzymatic Synthesis and Application of Bicyclo[2.2.2]octadiene Ligands: Increased Efficiency in Rhodium-Catalyzed Asymmetric Conjugate Additions by Electronic Tuning,ANGEWANDTE CHEMIE, Issue 15 2010Yunfei Luo Liganden nach Wunsch: Eine Serie von bicyclischen 1,4-Dimethyl[2.2.2]dien-Liganden mit flexibler Substitution in der Brücke ist durch Lipase-katalysierte Racematspaltung mit anschließender sechsstufiger Reaktionssequenz zugänglich. Die Methylgruppen am Brückenkopf führen zu einer erhöhten Reaktionseffizienz, wodurch in der Titelreaktion weniger Arylboronsäure nötig ist. [source] ChemInform Abstract: Chemoenzymatic Synthesis and Application of Bicyclo[2.2.2]octadiene Ligands: Increased Efficiency in Rhodium-Catalyzed Asymmetric Conjugate Additions by Electronic Tuning.CHEMINFORM, Issue 34 2010Yunfei Luo Abstract A new series of 1,4-disubstituted 2,5-diaryl bicyclo[2.2.2]octadienes are prepared. [source] ChemInform Abstract: Increased Efficiency in Cross-Metathesis Reactions of Sterically Hindered Olefins.CHEMINFORM, Issue 27 2008Ian C. Stewart Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Knowledge Life Cycle, Knowledge Inventory, and Knowledge Acquisition Strategies,DECISION SCIENCES, Issue 1 2010Andrew N. K. Chen ABSTRACT For a knowledge- and skill-centric organization, the process of knowledge management encompasses three important and closely related elements: (i) task assignments, (ii) knowledge acquisition through training, and (iii) maintaining a proper level of knowledge inventory among the existing workforce. Trade-off on choices between profit maximization in the short run and agility and flexibility in the long term is a vexing problem in knowledge management. In this study, we examine the effects of different training strategies on short-term operational efficiency and long-term workforce flexibility. We address our research objective by developing a computational model for task and training assignment in a dynamic knowledge environment consisting of multiple distinct knowledge dimensions. Overall, we find that organizational slack is an important variable in determining the effectiveness of training strategies. Training strategies focused on the most recent skills are found to be the preferred option in most of the considered scenarios. Interestingly, increased efficiencies in training can actually create preference conflict between employees and the firm. Our findings indicate that firms facing longer knowledge life cycles, higher slack in workforce capacity, and better training efficiencies actually face more difficult challenges in knowledge management. [source] Maturation of action monitoring from adolescence to adulthood: an ERP studyDEVELOPMENTAL SCIENCE, Issue 6 2005Alexandra M. Hogan This study investigated the development of the frontal lobe action-monitoring system from late childhood and adolescence to early adulthood using ERP markers of error processing. Error negativity (ERN) and correct response negativity (CRN) potentials were recorded while adolescents and adults (aged 12,22 years, n = 23) performed two forced-choice visual reaction time tasks of differing complexity. Significant age differences were seen for behavioural and ERP responses to complex (infrequent, incompatible) trials: adolescents elicited an error negativity of reduced magnitude compared with adults. Furthermore, in contrast to adults, adolescents showed a non-significant differentiation between response-locked ERP components elicited by correct (CRN) and error responses (ERN). Behaviourally, adolescents corrected fewer errors in incompatible trials, and with increasing age there was greater post-error slowing. In conclusion, the neural systems underlying action-monitoring continue to mature throughout the second decade of life, and are associated with increased efficiency for fast error detection and correction during complex tasks. [source] An evaluation of a visual biofeedback intervention in dyslexic adultsDYSLEXIA, Issue 1 2005Elizabeth Liddle Abstract A prototype of a biofeedback system designed to treat dyslexia by improving heart-rate variability was evaluated in a single blind study of dyslexic adults. Treatment consisted of four 15 minute exposures to a visual display synchronized with either the participant's own cardiac cycle (intervention condition), or of a synthesized cardiac cycle (placebo condition). Repeated measures were made of picture naming speed, single word reading speed and accuracy, copying speed, heart-rate variability and performance on a lateralized visual temporal order judgement task. Small but significant improvements were found in reading and naming speed in the treatment group relative to the placebo group. No significant improvements were found in unspeeded reading measures. Results from heart-rate measures indicated that treatment had effected a shift in the ratio between parameters reflecting the influence of the sympathetic and parasympathetic autonomic nervous systems (ANS), respectively, in favour of the parasympathetic. In the temporal order judgement task, participants who received treatment showed a reduced level of overall improvement relative to that seen in those who received placebo, coupled with evidence of a shift in visual attention from left to right hemifield in their pattern of performance. The results are interpreted as indicating that the treatment induces a shift in autonomic balance in favour of the parasympathetic ANS, and that this shift is also reflected in increased efficiency of left cerebral hemisphere circuits implicated in the perceptual-motor processes required for naming and reading fluency. Conversely, it is also reflected in lower spatial awareness of peripheral visual stimuli, particularly those presented to left hemifield. Copyright © 2004 John Wiley & Sons, Ltd. [source] Flies and concealed nectar sources: morphological innovations in the proboscis of Bombyliidae (Diptera)ACTA ZOOLOGICA, Issue 3 2002N. U. Szucsich Abstract Bee-flies (Bombyliidae) have morphological adaptations of the mouthparts to particular floral traits. To investigate this the short, plesiomorphic proboscis of Hemipenthes morio was compared with the long, apomorphic proboscis of Bombylius major. A novel feeding position enables B. major to use flowers that open to the side as additional nectar sources. The new horizontal feeding position is enabled by the prolonged ventral base of the proboscis. Bombylius major exploits deep corolla tubes with an elongate proboscis, and an increased efficiency in both the suction pumps and the sealing mechanisms of the proboscis. The exploitation of narrow corolla tubes is made possible by the shift from a sponging feeding mode, exhibited by H. morio, to the exclusively sucking mode in B. major. Besides quantitative changes in the proportions of the different proboscis components, labellar movements as well as the structures of saliva distribution are changed along with this shift. The labial musculature of B. major does not significantly differ from the plesiomorphic state, since both examined species do not only feed on nectar, but also on pollen. [source] Allee effect in larval resource exploitation in Drosophila: an interaction among density of adults, larvae, and micro-organismsECOLOGICAL ENTOMOLOGY, Issue 5 2002Bregje Wertheim Abstract 1. Aggregation pheromones can evolve when individuals benefit from clustering. Such a situation can arise with an Allee effect, i.e. a positive relationship between individual fitness and density of conspecifics. Aggregation pheromone in Drosophila induces aggregated oviposition. The aim of the work reported here was to identify an Allee effect in the larval resource exploitation by Drosophila melanogaster, which could explain the evolution of aggregation pheromone in this species. 2. It is hypothesised that an Allee effect in D. melanogaster larvae arises from an increased efficiency of a group of larvae to temper fungal growth on their feeding substrate. To test this hypothesis, standard apple substrates were infested with specified numbers of larvae, and their survival and development were monitored. A potential beneficial effect of the presence of adult flies was also investigated by incubating a varying number of adults on the substrate before introducing the larvae. Adults inoculate substrates with yeast, on which the larvae feed. 3. Fungal growth was related negatively to larval survival and the size of the emerging flies. Although the fungal growth on the substrate was largely reduced at increased larval densities, the measurements of fitness components indicated no Allee effect between larval densities and larval fitness, but rather indicated larval competition. 4. In contrast, increased adult densities on the substrates prior to larval development yielded higher survival of the larvae, larger emerging flies, and also reduced fungal growth on the substrates. Hence, adults enhanced the quality of the larval substrate and significant benefits of aggregated oviposition in fruit flies were shown. Experiments with synthetic pheromone indicated that the aggregation pheromone itself did not contribute directly to the quality of the larval resource. 5. The interaction among adults, micro-organisms, and larval growth is discussed in relation to the consequences for total fitness. [source] Toward detoxifying mercury-polluted aquatic sediments with rice genetically engineered for mercury resistanceENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2003Andrew C. P. Heaton Abstract Mercury contamination of soil and water is a serious problem at many sites in the United States and throughout the world. Plant species expressing the bacterial mercuric reductase gene, merA, convert ionic mercury, Hg(II), from growth substrates to the less toxic metallic mercury, Hg(0). This activity confers mercury resistance to plants and removes mercury from the plant and substrates through volatilization. Our goal is to develop plants that intercept and remove Hg(II) from polluted aquatic systems before it can undergo bacterially mediated methylation to the neurotoxic methylmercury. Therefore, the merA gene under the control of a monocot promoter was introduced into Oryza sativa L. (rice) by particle gun bombardment. This is the first monocot and first wetland-adapted species to express the gene. The merA -expressing rice germinated and grew on semisolid growth medium spiked with sufficient Hg(II) to kill the nonengineered (wild-type) controls. To confirm that the resistance mechanism was the conversion of Hg(II) to Hg(0), seedlings of merA -expressing O. sativa were grown in Hg(II)-spiked liquid medium or water-saturated soil media and were shown to volatilize significantly more Hg(0) than wild-type counterparts. Further genetic manipulation could yield plants with increased efficiency to extract soil Hg(II) and volatilize it as Hg(0) or with the novel ability to directly convert methylmercury to Hg(0). [source] Synaptic localization of GABAA receptor subunits in the substantia nigra of the rat: effects of quinolinic acid lesions of the striatumEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2002Fumino Fujiyama Abstract The inhibitory amino acid, ,-aminobutyric acid (GABA), plays a critical role in the substantia nigra (SN) in health and disease. GABA transmission is controlled in part by the type(s) of GABA receptor expressed, their subunit composition and their location in relation to GABA release sites. In order to define the subcellular localization of GABAA receptors in the SN in normal and pathological conditions, sections of SN from control rats and rats that had received quinolinic acid lesions of the striatum were immunolabelled using the postembedding immunogold technique with antibodies against subunits of the GABAA receptor. Immunolabelling for ,1, ,2/3 and ,2 subunits was primarily located at symmetrical synapses. Double-labelling revealed that ,2/3 subunit-positive synapses were formed by terminals that were enriched in GABA. Colocalization of ,1, ,2/3 and ,2 subunits occurred at individual symmetrical synapses, some of which were identified as degenerating terminals derived from the striatum. In the SN ipsilateral to the striatal lesion there was a significant elevation of immunolabelling for ,2/3 subunits of the GABAA receptor at symmetrical synapses, but not of GluR2/3 subunits of the AMPA receptor at asymmetrical synapses. It was concluded that fast GABAA -mediated transmission occurs primarily at symmetrical synapses within the SN, that different receptor subunits coexist at individual synapses and that the upregulation of GABAA receptors following striatal lesions is expressed as increased receptor density at synapses. The upregulation of GABAA receptors in Huntington's disease and its models is thus likely to lead to an increased efficiency of transmission at intact GABAergic synapses in the SN and may partly underlie the motor abnormalities of this disorder. [source] Solar Energy Collectors with Tunable TransmissionADVANCED FUNCTIONAL MATERIALS, Issue 9 2010Michael G. Debije Abstract A new type of "smart" window is proposed that makes use of fluorescent dye guests in a liquid-crystal host sandwiched between glass panels. The dye absorbs a variable amount of light depending on its orientation, and re-emits this light, of which a significant fraction is trapped by total internal reflection at the glass,air interface, and becomes concentrated along the edges. Such a device could both generate electricity via an attached photovoltaic as well as allow user control of the amount of transmitted light. By applying a voltage across the cell, absorption could be varied 31%, while the usable light output only varied 11% due to the increased efficiency of light collection at homeotropic dye orientation. [source] Environmental Values and Water PolicyGEOGRAPHICAL RESEARCH, Issue 3 2003Jeff Bennett Abstract The emergence of water markets has heralded the prospect of increased efficiency in the use of the resource for extractive purposes. However, water markets have not encompassed all elements of demand for the resource. Notably, demands for the environmental public goods provided by river flows have not been revealed in markets. State Governments have instituted regulations requiring ,environmental flows' to be quarantined from the market allocation process. This policy has triggered negative responses from irrigators and conservationists. Lobby groups have found that the process of determining environmental flows is a prospective site for rent seeking. To avoid policy being driven by rent seeking, information on the costs and benefits of environmental flows is useful. Whereas the costs of environmental flows are readily assessed through reference to market data on irrigators' surpluses foregone, the benefits must be estimated through the use of non-market, stated preference valuation techniques. These techniques , including contingent valuation and choice modelling , remain controversial. Some argue that they should not be used on ethical grounds. Others argue that they cannot be used on technical grounds. These arguments are discussed in this paper, using the context of the water policy debate. The evidence is that stated preference techniques are being used, and applications have been performed in Australia in the context of riverine health. However their use remains restricted relative to the scale of the Australian natural resource management task. Some possible explanations for this limited up-take are provided along with some suggested ways forward. [source] Photosensitization of TiO2 Nanostructures with CdS Quantum Dots: Particulate versus Tubular Support ArchitecturesADVANCED FUNCTIONAL MATERIALS, Issue 5 2009David R. Baker Abstract TiO2 nanotube arrays and particulate films are modified with CdS quantum dots with an aim to tune the response of the photoelectrochemical cell in the visible region. The method of successive ionic layer adsorption and reaction facilitates size control of CdS quantum dots. These CdS nanocrystals, upon excitation with visible light, inject electrons into the TiO2 nanotubes and particles and thus enable their use as photosensitive electrodes. Maximum incident photon to charge carrier efficiency (IPCE) values of 55% and 26% are observed for CdS sensitized TiO2 nanotube and nanoparticulate architectures respectively. The nearly doubling of IPCE observed with the TiO2 nanotube architecture is attributed to the increased efficiency of charge separation and transport of electrons. [source] Accounting for quality in the measurement of hospital performance: evidence from Costa RicaHEALTH ECONOMICS, Issue 7 2007Pablo Arocena Abstract This paper provides insights into how Costa Rican public hospitals responded to the pressure for increased efficiency and quality introduced by the reforms carried out over the period 1997,2001. To that purpose we compute a generalized output distance function by means of non-parametric mathematical programming to construct a productivity index, which accounts for productivity changes while controlling for quality of care. Our results show an improvement in hospital performance mainly driven by quality increases. The adoption of management contracts seems to have contributed to such enhancement, more notably for small hospitals. Further, productivity growth is primarily due to technical and scale efficiency change rather than technological change. A number of policy implications are drawn from these results. Copyright © 2006 John Wiley & Sons, Ltd. [source] COMPETITION AND REGULATION IN THE U.K. ELECTRICITY INDUSTRY (WITH A BRIEF LOOK AT CALIFORNIA)JOURNAL OF APPLIED CORPORATE FINANCE, Issue 4 2001Stephen C. Littlechild In this article, the U.K.'s Director General of Electricity Supply from 1989 to 1998 assesses the effects of deregulation and competition on the U.K. electricity industry after about a decade. Expansion of existing competitors, new entry, and further restructuring have reduced the aggregate share of the largest two generation companies from nearly 80% to 26%. Efficiency has improved and wholesale prices have fallen after an initial increase. Voluntary bilateral contracts markets are about to replace the mandatory "Pool," with centralised control limited to physically balancing the system and settling contract imbalances. Retail supply competition has been active for large industrial customers since the beginning, and 80% of them now buy from another supplier. The market for residential customers opened in early 1999, and already nearly a quarter of them have chosen another supplier. Incentive price controls on transmission and distribution have stimulated increased efficiency and significantly reduced use-of-system charges. Overall, prices for all classes of customers have fallen by 25,35% in real terms since privatisation, and quality of service has improved. California has adopted a policy that is similar in many respects, but with very different results. The problems there have stemmed partly from less favourable demand and supply conditions, but also from significant policy differences, including barriers to building new capacity, obstacles to the use of long-term supply (or hedging) contracts, retail price controls at untenable levels, and the requirement that (after a transition period) utilities pass through wholesale spot prices directly to their customers. Changes in such policies will eventually enable both producers and consumers in California to benefit from competition. [source] Hospitalists' awareness of patient charges associated with inpatient care,JOURNAL OF HOSPITAL MEDICINE, Issue 5 2010Jeremy D Graham MA Abstract Hospitalists' specialized focus on inpatient care services has been conjectured to offer increased efficiency and reduce costs of inpatient care. Hospitalists' estimates of the unadjusted patient-charges generated by commonly-used services were measured. Hospitalists' agreement with one another, and accuracy relative to the actual patient-charges were both low. Hospitalists' awareness of inpatient charges appears subject to the same opacity of pricing known to limit patient knowledge, and at present hospitalists' cognizance of charges and costs is unlikely to facilitate decreased care expenditures. Journal of Hospital Medicine 2010;5:295,297. © 2010 Society of Hospital Medicine [source] Supersensitivity of P2X7 receptors in cerebrocortical cell cultures after in vitro ischemiaJOURNAL OF NEUROCHEMISTRY, Issue 5 2005Kerstin Wirkner Abstract Neuronally enriched primary cerebrocortical cultures were exposed to glucose-free medium saturated with argon (in vitro ischemia) instead of oxygen (normoxia). Ischemia did not alter P2X7 receptor mRNA, although serum deprivation clearly increased it. Accordingly, P2X7 receptor immunoreactivity (IR) of microtubuline-associated protein 2 (MAP2)-IR neurons or of glial fibrillary acidic protein (GFAP)-IR astrocytes was not affected; serum deprivation augmented the P2X7 receptor IR only in the astrocytic, but not the neuronal cell population. However, ischemia markedly increased the ATP- and 2,-3,- O -(4-benzoylbenzoyl)-adenosine 5,-triphosphate (BzATP)-induced release of previously incorporated [3H]GABA. Both Brilliant Blue G and oxidized ATP inhibited the release of [3H]GABA caused by ATP application; the Brilliant Blue G-sensitive, P2X7 receptor-mediated fraction, was much larger after ischemia than after normoxia. Whereas ischemic stimulation failed to alter the amplitude of ATP- and BzATP-induced small inward currents recorded from a subset of non-pyramidal neurons, BzATP caused a more pronounced increase in the frequency of miniature inhibitory postsynaptic currents (mIPSCs) after ischemia than after normoxia. Brilliant Blue G almost abolished the effect of BzATP in normoxic neurons. Since neither the amplitude of mIPSCs nor that of the muscimol-induced inward currents was affected by BzATP, it is assumed that BzATP acts at presynaptic P2X7 receptors. Finally, P2X7 receptors did not enhance the intracellular free Ca2+ concentration either in proximal dendrites or in astrocytes, irrespective of the normoxic or ischemic pre-incubation conditions. Hence, facilitatory P2X7 receptors may be situated at the axon terminals of GABAergic non-pyramidal neurons. When compared with normoxia, ischemia appears to markedly increase P2X7 receptor-mediated GABA release, which may limit the severity of the ischemic damage. At the same time we did not find an accompanying enhancement of P2X7 mRNA or protein expression, suggesting that receptors may become hypersensitive because of an increased efficiency of their transduction pathways. [source] Potential prospects of chitosan derivative trimethyl chitosan chloride (TMC) as a polymeric absorption enhancer: synthesis, characterization and applicationsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 9 2008Jasjeet K. Sahni ABSTRACT In recent years, researchers have been working extensively on various novel properties of polymers to develop increased efficiency of drug delivery and improve bioavailability of various drug molecules, especially macromolecules. Chitosan, a naturally occurring polysaccharide, because of its protonated/polymeric nature, provides effective and safe absorption of peptide and protein drugs. Its transmucosal absorption is, however, limited to acidic media because of its strong intermolecular hydrogen bonds. A new partially quaternized chitosan derivative, N-trimethyl chitosan chloride (TMC), has been synthesized with improved solubility, safety and effectiveness as an absorption enhancer at neutral pH and in aqueous environment. It enhances the absorption, especially of peptide drugs, by reversible opening of tight junctions in between epithelial cells, thereby facilitating the paracellular diffusion of peptide drugs. This derivative thus opens new perspectives as a biomaterial for various pharmaceutical applications/drug delivery systems. This review deals with the potential use of the quaternized chitosan derivative as a permeation enhancer for the mucosal delivery of macromolecular drugs along with its other biomedical applications. [source] Food and feeding habits of smooth-coated otters (Lutra perspicillata) and their significance to the fish population of Kerala, IndiaJOURNAL OF ZOOLOGY, Issue 1 2005K. R. Anoop Abstract Feeding habits of smooth-coated otters Lutra perspicillata were studied by analysing spraints collected from around the Periyar Lake within the Periyar Tiger Reserve, Kerala, India. Remains were identified by the comparison of body parts with a reference collection of appropriate prey species. Two methods were used to estimate the proportions of different prey consumed: frequency of occurrence and score-bulk estimate. The number of prey types in a spraint varied between one and seven. More prey species were found during low water levels (March,April). Fish was the major prey, followed by frogs, crabs, birds and insects. Throughout the study, the exotic tilapia and European carp constituted the major prey in the diet. The quantity of native Deccan mahsheer and endemic Periyar barb in the diet was insignificant. A higher intake of bottom-dwelling catfish was observed during periods of low water, probably because of the increased efficiency of otters to forage at these levels. By consuming large amounts of exotic species, such as tilapia and European carp, otters might contribute to the control of the rapid expansion of these species in the Periyar Lake and adjacent water bodies in the reserve. [source] Differential binding to and biofilm formation on, HEp-2 cells by Salmonella enterica Serovar Typhimurium is dependent upon allelic variation in the fimH gene of the fim gene clusterMOLECULAR MICROBIOLOGY, Issue 5 2002Jennifer D. Boddicker Summary Type 1 fimbria-mediated adherence to HEp-2 cells by two strains of Salmonella enterica serovar Typhimurium was found to be different. Although both strains exhibited a strong mannose-sensitive haemagglutination reaction with guinea pig erythrocytes, characteristic of the expression of type 1 fimbriae, only one of the strains adhered in large numbers to HEp-2 cells. Characterization of the fimH genes, encoding the fimbrial adhesins, indicated two allelic variants. Using fimH mutants of the two strains it was possible to demonstrate that binding to HEp-2 cells was associated with the presence of one of the alleles regardless of the host strain. Therefore, this differential binding was not a function of the type I fimbrial shaft or the presence of other types of fimbriae produced by one strain but not the other. These observations may explain the differences in HEp-2 binding by type 1 fimbriate strains of Salmonella previously reported by several groups. Also, our studies demonstrate that the FimH adhesin can influence the efficiency of biofilm formation on HEp-2 cells using once-flow-through continuous culture conditions. The formation of biofilms on eukaryotic cells using this procedure is more likely to represent those conditions found in the intestinal tract than conditions using batch culture techniques to investigate adherence and biofilm formation. Indeed, the increased efficiency of biofilm formation in the murine intestinal tract confirmed the role of one of the fimH alleles in this process. [source] Crops and genotypes differ in efficiency of potassium uptake and usePHYSIOLOGIA PLANTARUM, Issue 4 2008Zed Rengel Cultivars with increased efficiency of uptake and utilization of soil nutrients are likely to have positive environmental effects through reduced usage of chemicals in agriculture. This review assesses the available literature on differential uptake and utilization efficiency of K in farming systems. Large areas of agricultural land in the world are deficient in K (e.g. 3/4 of paddy soils in China, 2/3 of the wheatbelt in Southern Australia), with export in agricultural produce (especially hay) and leaching (especially in sandy soils) contributing to lowering of K content in the soil. The capacity of a genotype to grow and yield well in soils low in available K is K efficiency. Genotypic differences in efficiency of K uptake and utilization have been reported for all major economically important plants. The K-efficient phenotype is a complex one comprising a mixture of uptake and utilization efficiency mechanisms. Differential exudation of organic compounds to facilitate release of non-exchangeable K is one of the mechanisms of differential K uptake efficiency. Genotypes efficient in K uptake may have a larger surface area of contact between roots and soil and increased uptake at the root,soil interface to maintain a larger diffusive gradient towards roots. Better translocation of K into different organs, greater capacity to maintain cytosolic K+ concentration within optimal ranges and increased capacity to substitute Na+ for K+ are the main mechanisms underlying K utilization efficiency. Further breeding for increased K efficiency will be dependent on identification of suitable markers and compounding of efficiency mechanisms into locally adapted germplasm. [source] Engineering photosynthetic light capture: impacts on improved solar energy to biomass conversionPLANT BIOTECHNOLOGY JOURNAL, Issue 6 2007Jan H. Mussgnug Summary The main function of the photosynthetic process is to capture solar energy and to store it in the form of chemical ,fuels'. Increasingly, the photosynthetic machinery is being used for the production of biofuels such as bio-ethanol, biodiesel and bio-H2. Fuel production efficiency is directly dependent on the solar photon capture and conversion efficiency of the system. Green algae (e.g. Chlamydomonas reinhardtii) have evolved genetic strategies to assemble large light-harvesting antenna complexes (LHC) to maximize light capture under low-light conditions, with the downside that under high solar irradiance, most of the absorbed photons are wasted as fluorescence and heat to protect against photodamage. This limits the production process efficiency of mass culture. We applied RNAi technology to down-regulate the entire LHC gene family simultaneously to reduce energy losses by fluorescence and heat. The mutant Stm3LR3 had significantly reduced levels of LHCI and LHCII mRNAs and proteins while chlorophyll and pigment synthesis was functional. The grana were markedly less tightly stacked, consistent with the role of LHCII. Stm3LR3 also exhibited reduced levels of fluorescence, a higher photosynthetic quantum yield and a reduced sensitivity to photoinhibition, resulting in an increased efficiency of cell cultivation under elevated light conditions. Collectively, these properties offer three advantages in terms of algal bioreactor efficiency under natural high-light levels: (i) reduced fluorescence and LHC-dependent heat losses and thus increased photosynthetic efficiencies under high-light conditions; (ii) improved light penetration properties; and (iii) potentially reduced risk of oxidative photodamage of PSII. [source] Compositional engineering of chemical bath deposited (Zn,Cd)S buffer layers for electrodeposited CuIn(S,Se)2 and coevaporated Cu(In,Ga)Se2 solar cellsPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 1 2009N. Naghavi Abstract A comparative study of chemical bath deposition (CBD) of ZnS, CdS, and a mixture of (Cd,Zn)S buffer layers has been carried out on electrodeposited CuIn(S,Se)2 (CISSe) and coevaporated Cu(In,Ga)Se2 (CIGS) absorbers. For an optimal bath composition with the ratio of [Zn]/[Cd],=,25, efficiencies higher than those obtained with CdS and ZnS recipes, both on co-evaporated CIGS and electrodeposited CISSe, have been obtained independent of the absorber used. In order to better understand the (Cd,Zn)S system and its impact on the increased efficiency of cells, predictions from the solubility diagrams of CdS and ZnS in aqueous medium were made. This analysis was completed by in situ growth studies with varying bath composition by quartz crystal microbalance (QCM). The morphology and composition of the films were studied using scanning electron microscopy (SEM) and X-ray photoelectron spectra (XPS) techniques. Preliminary XPS studies showed that films are composed of a mixture of CdS and Zn(O,OH) phases and not a pure ternary Cd1,,,xZnxS compound. The effect of the [Zn]/[Cd] molar ratio on properties of the corresponding CISSe and CIGS solar cells was investigated by current voltage [J(V)] and capacitance voltage [C(V)] characterizations. The origin of optimal results is discussed. Copyright © 2008 John Wiley & Sons, Ltd. [source] Next-generation transport systems: 4th generation MSPPSBELL LABS TECHNICAL JOURNAL, Issue 2 2006James A. Kraeutler Demand for Ethernet services is increasing exponentially worldwide. Improvements such as generic framing procedure (GFP) and virtual concatenation (VCAT) have been introduced, increasing the efficiency of synchronous optical network/synchronous digital hierarchy (SONET/SDH) transport for packet traffic. The growing volume of packet traffic necessitates further refinement of transport networking techniques toward a more packet-centric model that incorporates increased efficiency in handling packet traffic, and more packet-friendly optical networks; for example, multiprotocol label switching (MPLS) and generalized multiprotocol label switching (GMPLS) enabled networks. The most effective next-generation of multi-service provisioning platforms (MSPPs) must account for these realities and provide a solution for both bandwidth utilization and management capabilities while constituting a platform that can scale from last-mile access to metro core networks. These platforms should incorporate packet-based technologies including MPLS to provide a flexible and cost-effective mix of multi-service traffic engineering and encapsulation techniques, quality of service (QoS), security, and resiliency to providers competing in an increasingly packet-centric market. This paper explains how new transport systems are using novel architectures and exploiting new technologies to support emerging applications with network architectures best suited to the changing characteristics of the traffic they are required to carry. © 2006 Lucent Technologies Inc. [source] Metabolism of PER.C6TM cells cultivated under fed-batch conditions at low glucose and glutamine levelsBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2006Luis Maranga Abstract This is the first study to examine PER.C6TM cell glucose/energy and glutamine metabolism with fed-batch cultures at controlled low glutamine, low glucose, and simultaneous low glucose and low glutamine levels. PER.C6TM cell metabolism was investigated in serum-free suspension bioreactors at two-liter scale. Control of glucose and/or glutamine concentrations had a significant effect on cellular metabolism leading to an increased efficiency of nutrient utilization, altered byproduct synthesis, while having no effect on cell growth rate. Cultivating cells at a controlled glutamine concentration of 0.25 mM reduced qGln and q by approximately 30%, qAla 85%, and qNEAA 50%. The fed-batch control of glutamine also reduced the overall accumulation of ammonium ion by approximately 50% by minimizing the spontaneous chemical degradation of glutamine. No major impact upon glucose/energy metabolism was observed. Cultivating cells at a glucose concentration of 0.5 mM reduced qGlc about 50% and eliminated lactate accumulation. Cells exhibited a fully oxidative metabolism with Y of approximately 6 mol/mol. However, despite no increase in qGln, an increased ammonium ion accumulation and Y were also observed. Effective control of lactate and ammonium ion accumulation by PER.C6TM cells was achieved using fed-batch with simultaneously controlled glucose and glutamine. A fully oxidative glucose metabolism and a complete elimination of lactate production were obtained. The qGln value was again reduced and, despite an increased q compared with batch culture, ammonium ion levels were typically lower than corresponding ones in batch cultures, and the accumulation of non-essential amino acids (NEAA) was reduced about 50%. In conclusion, this study shows that PER.C6TM cell metabolism can be confined to a state with improved efficiencies of nutrient utilization by cultivating cells in fed-batch at millimolar controlled levels of glucose and glutamine. In addition, PER.C6TM cells fall into a minority category of mammalian cell lines for which glutamine plays a minor role in energy metabolism. © 2006 Wiley Periodicals, Inc. [source] FOREIGN CAPITAL AND EFFICIENCY IN DEVELOPING COUNTRIESBULLETIN OF ECONOMIC RESEARCH, Issue 4 2008Camilla Mastromarco O47; O57 ABSTRACT This paper uses stochastic frontier methodology to analyse foreign direct investment, imported capital goods and human capital as channels for increased efficiency in less-developed countries. Empirical investigation reveals that developing countries differ with respect to the efficiency with which they use frontier technology. Foreign direct investment and human capital play a significant and quantitatively important role in explaining these differences. [source] Screening and prevention of diabetic blindnessACTA OPHTHALMOLOGICA, Issue 4 2000Einar Stefánsson ABSTRACT. : Diabetic eye disease remains a major cause of blindness in the world. Laser treatment for proliferative diabetic retinopathy and diabetic macular edema became available more than two decades ago. The outcome of treatment depends on the timing of laser treatment. The laser treatment is optimally delivered when high-risk characteristics have developed in proliferative retinopathy or diabetic macular edema and before this has significantly affected vision. Laser treatment is usually successful if applied during this optimal period whereas the treatment benefit falls sharply if the treatment is applied too late. In order to optimize the timing of laser treatment in diabetic eye disease screening programs have been established. The oldest screening program is 20 years old and several programs have been established during the last decade. In this paper the organisation and methods of screening programs are described including direct and photographic screening. The incidence and prevalence of blindness is much lower in populations where screening for diabetic eye disease has been established compared to diabetic populations without screening. Technical advantages may allow increased efficiency and telescreening. From a public health standpoint screening for diabetic eye disease is one of the most cost effective health procedures available. Diabetic eye disease can be prevented using existing technology and the cost involved is many times less than the cost of diabetic blindness. [source] | ||||||||||||||||||||||||||||||||||