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Efficient Means (efficient + mean)
Selected AbstractsEffects of methylcyclodextrin on lysosomesFEBS JOURNAL, Issue 5 2001Michel Jadot The cholesterol complexing agent methyl-cyclodextrin (MCD) provides an efficient mean for the removal of cholesterol from biological membranes. In order to study the effects of this agent on the lysosomal membrane in situ, we treated HepG2 cells with MCD and studied the effects of this treatment on lysosomes in isolated fractions. We found that lysosomes prepared from treated cells are more sensitive to various membrane perturbing treatments such as: incubation of lysosomes in isotonic glucose, in hypotonic sucrose or in the presence of the lytic agent glycyl- l -phenylalanine 2-naphthylamide. The lysosomal membrane is also less resistant to increased hydrostatic pressure. Centrifugation methods were used to analyse the effect of MCD on lysosomes. Isopycnic centrifugation in sucrose density gradients demonstrates that the drug induces a reversible density increase of the lysosomes. Our study indicates that extracellularly added MCD can modify the properties of the lysosomal membrane in living cells. It suggests that MCD could be an effective tool to modulate the physical properties of lysosomes within intact cells and to monitor the cellular responses to such modifications. [source] Joule heating in electrokinetic flowELECTROPHORESIS, Issue 1 2008Xiangchun Xuan ProfessorArticle first published online: 30 NOV 200 Abstract Electrokinetic flow is an efficient means to manipulate liquids and samples in lab-on-a-chip devices. It has a number of significant advantages over conventional pressure-driven flow. However, there exists inevitable Joule heating in electrokinetic flow, which is known to cause temperature variations in liquids and draw disturbances to electric, flow and concentration fields via temperature-dependent material properties. Therefore, both the throughput and the resolution of analytic studies performed in microfluidic devices are affected. This article reviews the recent progress on the topic of Joule heating and its effect in electrokinetic flow, particularly the theoretical and experimental accomplishments from the aspects of fluid mechanics and heat/mass transfer. The primary focus is placed on the temperature-induced flow variations and the accompanying phenomena at the whole channel or chip level. [source] Monogenic diabetes: information seeking and genetic testing access via e-mailEUROPEAN DIABETES NURSING, Issue 2 2010M Shepherd RGN, PhD Honorary Clinical Senior Lecturer Abstract Background: Confirmation of monogenic diabetes by molecular genetic testing has allowed many patients, often previously assumed to have type 1 diabetes, to transfer from insulin injections to sulphonylurea tablets, with improvements in glycaemic control and quality of life: www.diabetesgenes.org provides information about monogenic diabetes and genetic testing. Aim: To investigate key issues raised by individuals who e-mailed the monogenic diabetes team about genetic testing and monogenic diabetes management. Methods: Sixty e-mail enquiries, received over a six-month period from patients and professionals worldwide, were analysed using a qualitative thematic content approach. Results: Five themes emerged: 1. Accessing genetic technology: patients and professionals both enquired about access to testing; 2. Presentation of evidence: medical facts presented by patients and professionals included characteristics specifically relevant to diagnosing monogenic diabetes; 3. Experiences of healthcare: patients often researched their condition online and some felt dissatisfied with routine consultations; 4. Seeking specialist advice regarding treatment: specific information was sought relating to management of neonatal diabetes or monogenic diabetes and pregnancy; 5. Searching for a cure through genetic technology: patients questioned whether genetic advances would lead to a cure for diabetes. Conclusion: This project offers the first insights into use of e-mail as a means of gaining access to a specialist monogenic team and information about genetic testing. Although providing advice via e-mail can prove complicated, particularly when received from patients under the care of other clinicians, it is an efficient means of communicating specialist knowledge. Study findings will aid development of a ,frequently asked questions' section of www.diabetesgenes.org. Copyright © 2010 FEND [source] Frequency domain equalisation in CDMA detectionEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 2 2008Ihan Martoyo The present paper introduces frequency domain equalisation (FDE) as an efficient means for single-user detection (SUD) in universal mobile telecommunication systems (UMTS) handhelds. Such an SUD is, at least partially, able to remove multiple access interference (MAI) like a multi-user detector (MUD), however with several important advantages the operation principle of an FDE-SUD is simple and easy to understand, the FDE-SUD shows low numerical complexity and therefore, it is not power hungry like an MUD. The problem of applying FDE without zero-padding or cyclic-prefix insertion is solved by using the overlap-cut method. In this paper we also prove that the performance of the FDE-SUD is practically identical to that of linear MUD for a fully loaded UMTS cell. Furthermore, armed with the idea of FDE for code division multiple access (CDMA), we can construct a common receiver structure for CDMA, time division multiple access (TDMA), orthogonal frequency division multiplexing (OFDM) and multi-carrier CDMA (MC-CDMA) systems. This is an extremely useful idea in enabling a software-defined radio (SDR) which can operate seamlessly in several environments such as UMTS, the IEEE 802.11a and WiMaX. FDE based receivers could be one important building-block for the next generation mobile communications. Copyright © 2008 John Wiley & Sons, Ltd. [source] Contribution of gravitational potential energy differences to the global stress fieldGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2009Attreyee Ghosh SUMMARY Modelling the lithospheric stress field has proved to be an efficient means of determining the role of lithospheric versus sublithospheric buoyancies and also of constraining the driving forces behind plate tectonics. Both these sources of buoyancies are important in generating the lithospheric stress field. However, these sources and the contribution that they make are dependent on a number of variables, such as the role of lateral strength variation in the lithosphere, the reference level for computing the gravitational potential energy per unit area (GPE) of the lithosphere, and even the definition of deviatoric stress. For the mantle contribution, much depends on the mantle convection model, including the role of lateral and radial viscosity variations, the spatial distribution of density buoyancies, and the resolution of the convection model. GPE differences are influenced by both lithosphere density buoyancies and by radial basal tractions that produce dynamic topography. The global lithospheric stress field can thus be divided into (1) stresses associated with GPE differences (including the contribution from radial basal tractions) and (2) stresses associated with the contribution of horizontal basal tractions. In this paper, we investigate only the contribution of GPE differences, both with and without the inferred contribution of radial basal tractions. We use the Crust 2.0 model to compute GPE values and show that these GPE differences are not sufficient alone to match all the directions and relative magnitudes of principal strain rate axes, as inferred from the comparison of our depth integrated deviatoric stress tensor field with the velocity gradient tensor field within the Earth's plate boundary zones. We argue that GPE differences calibrate the absolute magnitudes of depth integrated deviatoric stresses within the lithosphere; shortcomings of this contribution in matching the stress indicators within the plate boundary zones can be corrected by considering the contribution from horizontal tractions associated with density buoyancy driven mantle convection. Deviatoric stress magnitudes arising from GPE differences are in the range of 1,4 TN m,1, a part of which is contributed by dynamic topography. The EGM96 geoid data set is also used as a rough proxy for GPE values in the lithosphere. However, GPE differences from the geoid fail to yield depth integrated deviatoric stresses that can provide a good match to the deformation indicators. GPE values inferred from the geoid have significant shortcomings when used on a global scale due to the role of dynamically support of topography. Another important factor in estimating the depth integrated deviatoric stresses is the use of the correct level of reference in calculating GPE. We also elucidate the importance of understanding the reference pressure for calculating deviatoric stress and show that overestimates of deviatoric stress may result from either simplified 2-D approximations of the thin sheet equations or the assumption that the mean stress is equal to the vertical stress. [source] Combining spatial and phylogenetic eigenvector filtering in trait analysisGLOBAL ECOLOGY, Issue 6 2009Ingolf Kühn ABSTRACT Aim, To analyse the effects of simultaneously using spatial and phylogenetic information in removing spatial autocorrelation of residuals within a multiple regression framework of trait analysis. Location, Switzerland, Europe. Methods, We used an eigenvector filtering approach to analyse the relationship between spatial distribution of a trait (flowering phenology) and environmental covariates in a multiple regression framework. Eigenvector filters were calculated from ordinations of distance matrices. Distance matrices were either based on pure spatial information, pure phylogenetic information or spatially structured phylogenetic information. In the multiple regression, those filters were selected which best reduced Moran's I coefficient of residual autocorrelation. These were added as covariates to a regression model of environmental variables explaining trait distribution. Results, The simultaneous provision of spatial and phylogenetic information was effectively able to remove residual autocorrelation in the analysis. Adding phylogenetic information was superior to adding purely spatial information. Applying filters showed altered results, i.e. different environmental predictors were seen to be significant. Nevertheless, mean annual temperature and calcareous substrate remained the most important predictors to explain the onset of flowering in Switzerland; namely, the warmer the temperature and the more calcareous the substrate, the earlier the onset of flowering. A sequential approach, i.e. first removing the phylogenetic signal from traits and then applying a spatial analysis, did not provide more information or yield less autocorrelation than simple or purely spatial models. Main conclusions, The combination of spatial and spatio-phylogenetic information is recommended in the analysis of trait distribution data in a multiple regression framework. This approach is an efficient means for reducing residual autocorrelation and for testing the robustness of results, including the indication of incomplete parameterizations, and can facilitate ecological interpretation. [source] Sibling rivalry: competition between Pol X family members in V(D)J recombination and general double strand break repairIMMUNOLOGICAL REVIEWS, Issue 1 2004Stephanie A. Nick McElhinny Summary:, The nonhomologous end-joining pathway is a major means for repairing double-strand breaks (DSBs) in all mitotic cell types. This repair pathway is also the only efficient means for resolving DSB intermediates in V(D)J recombination, a lymphocyte-specific genome rearrangement required for assembly of antigen receptors. A role for polymerases in end-joining has been well established. They are a major factor in determining the character of repair junctions but, in contrast to ,core' end-joining factors, typically appear to have a subtle impact on the efficiency of end-joining. Recent work implicates several members of the Pol X family in end-joining and suggests surprising complexity in the control of how these different polymerases are employed in this pathway. [source] Photoluminescent Nanoparticle Surfaces: The Potential of Alkaline Earth Oxides for Optical Applications,ADVANCED MATERIALS, Issue 24 2008Andreas Sternig The surfaces of alkaline earth oxides emit bright, colored light and have potential as thermally stable inorganic phosphors with adsorption-dependent optical properties. The doping of thermally stable MgO nanocubes with low-coordinated BaO surface elements (see figure) clearly demonstrates that chemical manipulation of the solid,gas interface provides an efficient means to adjust the optical properties of powders in controlled gas atmospheres. [source] Nursing Outcomes for Evaluations of Caregiver Outcomes in a Rural Alzheimer Demonstration ProjectINTERNATIONAL JOURNAL OF NURSING TERMINOLOGIES AND CLASSIFICATION, Issue 2003Janet Specht PURPOSE To evaluate the effectiveness of the interventions of nurse care managers in the care of family members of people with dementia. METHODS Data were collected as part of a 3-year Administration on Aging,funded Alzheimer Demonstration Project to provide expanded in-home services to rural Iowans affected by Alzheimer disease and related disorders in 8 rural Iowa counties,randomly selected to have a nurse care manager and 4 designated control counties that had traditional case management service. Nurse care managers were trained in the care of people with dementia and their caregivers, the use of role transition theory, and the Progressively Lowered Stress Threshold model of care to provide and coordinate services for enrollees. All referred people with cognitive impairment and their families in the 8 study counties were eligible for inclusion. Three selected NOC outcomes were tested in clinical settings. Interrater reliability for the outcomes was good (87%,95%). The construct validity of Caregiver Stressors Outcome was .74 when correlated with the Caregiver Stress Index. FINDINGS Of the 142 subjects with cognitive impairment enrolled within the first year of the grant, 113 had a caregiver. The outcomes were used to evaluate differences in caregiver outcomes at baseline and at 6-month intervals. The majority of caregivers at follow-up was female and had been providing care for ,5 years. For each of the outcomes the majority of caregivers had improved scores, with only 2,4 caregivers getting scores indicating worsening conditions or remaining the same. CONCLUSIONS Preliminary analysis shows a trend of improved outcomes with the use of a nurse care manager. The NOC caregiver outcomes showed good variability among caregivers at baseline, with caregiver responses distributed throughout the scales. The NOC outcomes also provide guidance for interventions of the nurse care managers. Further evaluation of the outcomes is needed, including examining the relationships of placement, health status, and service use of each outcome. The caregiver outcomes offer an effective and efficient means to evaluate services delivered to caregivers of people with dementia. [source] Cognitive Screening Using a Tape Recorder: A Pilot StudyJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 3 2003Peter W. Schofield MD OBJECTIVES: To determine whether a tape recorder can be used to administer cognitive tests efficiently and yield valid results. DESIGN: Convenience sample. Administration of cognitive test materials by tape recorder and conventional technique. SETTING: Outpatient clinic. PARTICIPANTS: Subjects from memory disorder clinic, hostel accommodation, and community. MEASUREMENTS: Responses to Hopkins Verbal Learning Test,revised, verbal fluency items from the controlled oral word association test, 10-item naming task, a construction task, and speed writing task. RESULTS: Performances on the tape- and clinician-administered battery of tests were highly correlated. Memory impairment was accurately detected using the tape battery. Data from 30 minutes of testing via tape were obtained at the cost to the clinician of 2 to 3 minutes of scoring time. CONCLUSION: Tape-administration of cognitive test material warrants further study as an efficient means of cognitive screening. [source] A cyberenvironment for crystallography and materials science and an integrated user interface to the Crystallography Open Database and Predicted Crystallography Open DatabaseJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2008Jacob R. Fennick With the advent and subsequent evolution of the Internet the ways in which computational crystallographic research is conducted have dramatically changed. Consequently, secure, robust and efficient means of accessing remote data and computational resources have become a necessity. At present scientists in computational crystallography access remote data and resources via separate technologies, namely SSH and Web services. Computational Science and Engineering Online (CSE-Online) combines these two methods into a single seamless environment while simultaneously addressing issues such as stability with regard to Internet interruption. Presently CSE-Online contains several applications which are useful to crystallographers; however, continued development of new tools is necessary. Toward this end a Java application capable of running in CSE-Online, namely the Crystallography Open Database User Interface (CODUI), has been developed, which allows users to search for crystal structures stored in the Crystallography Open Database and Predicted Crystallography Open Database, to export structural data for visualization, or to input structural data in other CSE-Online applications. [source] How you count counts: the importance of methods research in applied ecologyJOURNAL OF APPLIED ECOLOGY, Issue 5 2008Chris S. Elphick Summary 1Methods papers play a crucial role in advancing applied ecology. Counting organisms, in particular, has a rich history of methods development with many key advances both in field sampling and the treatment of resulting data. 2Most counts, however, have associated errors due to portions of the population of interest being unavailable for detection (e.g. target population not fully sampled; individuals present but not detectable), detection mistakes (e.g. detectable individuals missed; non-existent individuals recorded), or erroneous counts (e.g. large groups miscounted; individuals misidentified). 3Developments in field methods focus on reducing biases in the actual counts. Simultaneously, statisticians have developed many methods for improving inference by quantifying and correcting for biases retrospectively. Prominent examples of methods used to account for detection errors include distance sampling and multiple-observer methods. 4Simulations, in which population characteristics are set by the investigator, provide an efficient means of testing methods. With good estimates of sampling biases, computer simulations can be used to evaluate how much a given counting problem affects estimates of parameters such as population size and decline, thereby allowing applied ecologists to test the efficacy of sampling designs. Combined with cost estimates for each field method, such models would allow the cost-effectiveness of alternative protocols to be assessed. 5Synthesis and applications. Major advances are likely to come from research that looks for systematic patterns, across studies, in the effects of different types of bias and assumption violation on the ecological conclusions drawn. Specifically, determining how often, and under what circumstances, errors contribute to poor management and policy would greatly enhance future application of ecological knowledge. [source] Decrease of enteric micro-organisms from rural sewage sludge during their composting in straw mixtureJOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2005A.-M. Pourcher Abstract Aims:, To study the decrease of enteric micro-organisms including viable nematode eggs, enteroviruses, faecal indicators (Escherichia coli and enterococci) and pathogenic bacteria (Listeria monocytogenes, Salmonella sp. and Clostridium perfringens) of a rural sewage sludge when it is composted for 7 months in mixture with straw. Methods and Results:, Numbers of the test organisms and the physico-chemical parameters were measured on a monthly basis on the mixture, on the compost after being turned, and on the pile in three positions representing the part by which air is incoming, the bottom of the pile and the part through which air is outgoing. The lowest temperature in the pile was observed at the bottom, where it did not exceed 50°C against 66°C in the two other areas. There were no significant differences between the three areas in terms of micro-organism survival. Infectious enteroviruses were inactivated rapidly and were not found after the first turning whereas some genomes were detected until after the third turning. Escherichia coli and enterococci presented a similar survival rate and their number decreased by 4 log10 whereas Salmonella decayed at a greater rate than L. monocytogenes. The numbers of C. perfringens decreased gradually to reach a final concentration in the mature compost of about 102 CFU g,1 dry matter (d.m.), which was similar to that of the faecal indicators. Conclusions:, The hygienic effect of sludge composting in mixture with straw results in a significant reduction of enteric micro-organisms, the concentration of the faecal indicators in the final product being <64 most probable number g,1 d.m. The concentrations of Salmonella, enteroviruses and viable nematode eggs in the final product were not detectable which is in accordance with the French legislation. Significance and Impact of the Study:, The results which pointed out the different behaviour of the test micro-organisms reflect the difficulty to propose a relevant indicator of hygienization. Otherwise, they show that composting is an efficient means for hygienization of sludge of rural wastewater treatment, where the straw is available close to their place of production. [source] Historical and contemporary distributions of carnivores in forests of the Sierra Nevada, California, USAJOURNAL OF BIOGEOGRAPHY, Issue 8 2005William J. Zielinski Abstract Aim, Mammalian carnivores are considered particularly sensitive indicators of environmental change. Information on the distribution of carnivores from the early 1900s provides a unique opportunity to evaluate changes in their distributions over a 75-year period during which the influence of human uses of forest resources in California greatly increased. We present information on the distributions of forest carnivores in the context of two of the most significant changes in the Sierra Nevada during this period: the expansion of human settlement and the reduction in mature forests by timber harvest. Methods, We compare the historical and contemporary distributions of 10 taxa of mesocarnivores in the conifer forests of the Sierra Nevada and southern Cascade Range by contrasting the distribution of museum and fur harvest records from the early 1900s with the distribution of detections from baited track-plate and camera surveys conducted from 1996 to 2002. A total of 344 sample units (6 track plates and 1 camera each) were distributed systematically across c. 3,000,000 ha area over a 7-year period. Results, Two species, the wolverine (Gulo gulo) and the red fox (Vulpes vulpes), present in the historical record for our survey area, were not detected during the contemporary surveys. The distributions of 3 species (fisher [Martespennanti], American marten [M. americana], and Virginia opossum [Didelphisvirginiana]) have substantially changed since the early 1900s. The distributions of fishers and martens, mature-forest specialists, appeared to have decreased in the northern Sierra Nevada and southern Cascade region. A reputed gap in the current distribution of fishers was confirmed. We report for the first time evidence that the distribution of martens has become fragmented in the southern Cascades and northern Sierra Nevada. The opossum, an introduced marsupial, expanded its distribution in the Sierra Nevada significantly since it was introduced to the south-central coast region of California in the 1930s. There did not appear to be any changes in the distributions of the species that were considered habitat generalists: gray fox (Urocyon cinereoargenteus), striped skunk (Mephitis mephitis), western spotted skunk (Spilogale gracilis), or black bear (Ursus americanus). Detections of raccoons (Procyon lotor) and badgers (Taxidea taxus) were too rare to evaluate. Contemporary surveys indicated that weasels (M. frenata and M. erminea) were distributed throughout the study area, but historical data were not available for comparison. Main conclusions, Two species, the wolverine and Sierra Nevada red fox, were not detected in contemporary surveys and may be extirpated or in extremely low densities in the regions sampled. The distributions of the mature forest specialists (marten and fisher) appear to have changed more than the distributions of the forest generalists. This is most likely due to a combination of loss of mature forest habitat, residential development and the latent effects of commercial trapping. Biological characteristics of individual species, in combination with the effect of human activities, appear to have combined to affect the current distributions of carnivores in the Sierra Nevada. Periodic resampling of the distributions of carnivores in California, via remote detection methods, is an efficient means for monitoring the status of their populations. [source] Exploratory factor analysis of the research and development culture index among qualified nursesJOURNAL OF CLINICAL NURSING, Issue 9 2005Bill Watson MSc Aims and objectives., This paper presents the exploratory factor analysis of a rating instrument for assessing the strength of organizational Research and Development (R&D) culture. Background., Despite nursing's limited research capacity, the discipline is capitalising upon opportunities to become involved in research and is making strong progress. Within the context of the debate on nursing research capacity, the R&D Culture Index was developed as a means of appraising R&D culture within health care organizations. Design., Factor analysis was carried out on data collected from 485 nursing staff. The method of extraction was Principal Components Analysis with oblique rotation. Methods., The Index was developed from the findings of qualitative research conducted with NHS staff. Eighteen items, encompassing the main themes from the data, were initially included in the Index. This pilot instrument was distributed to nursing staff within three different types of NHS Trust. Factor analysis resulted in rejection of two items and the analysis was repeated using the remaining 16 items. Results., Three latent factors were extracted accounting for 58·0% of the variance in the data. The factors were: R&D Support, describing the perceived support within the working environment for R&D activity; Personal R&D Skills and Aptitude, describing an individual's perception of their ability towards R&D activity; and Personal R&D Intention, describing an individual's willingness to engage in R&D activity. Each factor had good internal reliability, as did the overall index. Conclusion., The R&D Culture Index provides an efficient means of assessing the strength of an organization's R&D culture in a way that captures the role of the individual practitioner and the organizational environment. Relevance to practice., These findings suggest that the continuing promotion of R&D within health care organizations is dependent upon a multi-faceted approach that addresses the learning needs of the organization as well as those of the individual practitioners. [source] Trauma focus group therapy for combat-related PTSD: An updateJOURNAL OF CLINICAL PSYCHOLOGY, Issue 8 2002David W. Foy Individual cognitive,behavioral therapy involving directed exposure to memories of traumatic events has been found to be effective in treating posttraumatic stress disorder. In this article, we present updated information on an alternative group form of exposure therapy: manualized trauma-focus group therapy (TFGT), designed as an efficient means of conducting directed exposure. We describe the cognitive,behavioral and developmental models from which the approach was derived, present an overview of session topics and a case illustration, provide guidelines for referring individuals to TFGT, and offer suggestions for future research. © 2002 Wiley Periodicals, Inc. J Clin Psychol/In Session 58: 907,918, 2002. [source] Effect of High-Pressure Processing on Vibrio parahaemolyticus Strains in Pure Culture and Pacific OystersJOURNAL OF FOOD SCIENCE, Issue 4 2002H. Calik ABSTRACT Different strains of Vibrio parahaemolyticus (Vp) in broth cultures and Vp-inoculated live Pacific oysters (Crassostrea gigas) were subjected to high-pressure processing (HPP) at 241, 276, 310, and 345 MPa. Results showed Vp numbers were reduced by HPP in both pure culture and whole oysters. Vp inactivation was dependent on time and pressure. Optimum conditions for reducing Vp in pure culture and oysters to nondetectable levels were achieved at 345 MPa for 30 and 90 s, respectively. Resistance variations were detected between Vp in pure culture and in oysters. HPP proved to be an efficient means of reducing Vp in oysters. [source] Hairy Root and Its Application in Plant Genetic EngineeringJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 2 2006Zhi-Bi Hu Abstract Agrobacterium rhizogenes Conn. causes hairy root disease in plants. Hairy root-infected A. rhizogenes is characterized by a high growth rate and genetic stability. Hairy root cultures have been proven to be an efficient means of producing secondary metabolites that are normally biosynthesized in roots of differentiated plants. Furthermore, a transgenic root system offers tremendous potential for introducing additional genes along with the Ri plasmid, especially with modified genes, into medicinal plant cells with A. rhizogenes vector systems. The cultures have turned out to be a valuable tool with which to study the biochemical properties and the gene expression profile of metabolic pathways. Moreover, the cultures can be used to elucidate the intermediates and key enzymes involved in the biosynthesis of secondary metabolites. The present article discusses various applications of hairy root cultures in plant genetic engineering and potential problems associated with them. (Managing editor: Wei Wang) [source] Characterization of conantokin Rl -A: molecular phylogeny as structure/function studyJOURNAL OF PEPTIDE SCIENCE, Issue 8 2010Konkallu H. Gowd Abstract A multidisciplinary strategy for discovery of new Conus venom peptides combines molecular genetics and phylogenetics with peptide chemistry and neuropharmacology. Here we describe application of this approach to the conantokin family of conopeptides targeting NMDA receptors. A new conantokin from Conus rolani, ConRl -A, was identified using molecular phylogeny and subsequently synthesized and functionally characterized. ConRl -A is a 24-residue peptide containing three ,-carboxyglutamic acid residues with a number of unique sequence features compared to conantokins previously characterized. The HPLC elution of ConRl -A suggested that this peptide exists as two distinct, slowly exchanging conformers. ConRl -A is predominantly helical (estimated helicity of 50%), both in the presence and absence of Ca++. The order of potency for blocking the four NMDA receptor subtypes by ConRl -A was NR2B > NR2D > NR2A > NR2C. This peptide has a greater discrimination between NR2B and NR2C than any other ligand reported so far. In summary, ConRl -A is a new member of the conantokin family that expands our understanding of structure/function of this group of peptidic ligands targeted to NMDA receptors. Thus, incorporating phylogeny in the discovery of novel ligands for the given family of ion channels or receptors is an efficient means of exploring the megadiverse group of peptides from the genus Conus. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd. [source] Photosynthetic Responses of a Temperate Liana to Xylella fastidiosa Infection and Water StressJOURNAL OF PHYTOPATHOLOGY, Issue 1 2004A. J. McElrone Abstract Xylella fastidiosa is a xylem-limited bacterial plant pathogen that causes bacterial leaf scorch in its hosts. Our previous work showed that water stress enhances leaf scorch symptom severity and progression along the stem of a liana, Parthenocissus quinquefolia, infected by X. fastidiosa. This paper explores the photosynthetic gas exchange responses of P. quinquefolia, with the aim to elucidate mechanisms behind disease expression and its interaction with water stress. We used a 2 × 2-complete factorial design, repeated over two growing seasons, with high and low soil moisture levels and infected and non-infected plants. In both years, low soil moisture levels reduced leaf water potentials, net photosynthesis and stomatal conductance at all leaf positions, while X. fastidiosa -infection reduced these parameters at basally located leaves only. Intercellular CO2 concentrations were reduced in apical leaves, but increased at the most basal leaf location, implicating a non-stomatal reduction of photosynthesis in leaves showing the greatest disease development. This result was supported by measured reductions in photosynthetic rates of basal leaves at high CO2 concentrations, where stomatal limitation was eliminated. Repeated measurements over the summer of 2000 showed that the effects of water stress and infection were progressive over time, reaching their greatest extent in September. By reducing stomatal conductances at moderate levels of water stress, P. quinquefolia maintained relatively high leaf water potentials and delayed the onset of photosynthetic damage due to pathogen and drought-induced water stress. In addition, chlorophyll fluorescence measurements showed that P. quinquefolia has an efficient means of dissipating excess light energy that protects the photosynthetic machinery of leaves from irreversible photoinhibitory damage that may occur during stress-induced stomatal limitation of photosynthesis. However, severe stress induced by disease and drought eventually led to non-stomatal decreases in photosynthesis associated with leaf senescence. [source] Two-beam multiplexed CARS based on a broadband oscillator,JOURNAL OF RAMAN SPECTROSCOPY, Issue 8 2010Kentaro Furusawa Abstract A two-beam multiplexed coherent anti-Stokes Raman scattering (CARS) microscopy setup is demonstrated by using a broadband (BB) Ti:sapphire oscillator without using any specialty fibres. A well-defined spectral structure of the source leads to a delay-sensitive CARS measurement in two-colour CARS and also provides an efficient means of obtaining three-colour CARS signals combined with the dispersion compensation of the BB pulse. Our result implies that the background suppression is limited by the onset of the spurious signals caused by the different CARS process, qualitatively differing from what is typically observed in the CARS microscopy. Copyright © 2010 John Wiley & Sons, Ltd. [source] Orientation and Phase Relationships between Titania Films and Polycrystalline BaTiO3 Substrates as Determined by Electron Backscatter Diffraction MappingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2010Nina V. Burbure Titania films have been grown on polycrystalline BaTiO3 (BTO) substrates at 700°C by pulsed laser deposition. Electron backscatter diffraction (EBSD) was used to determine grain orientations in the substrate before growth, and the phase and orientation of the supported films after growth. All BaTiO3 grains within 26° of (001) were covered by anatase films with an orientation relationship of (001)Anatase||(001)BTO and [100]Anatase||[100]BTO. Rutile with a variety of orientations grew on BaTiO3 grains with orientations closer to (110) and (111). EBSD mapping provides an efficient means for determining phase and orientation relationships of films over all orientation parameters. [source] A Solvent Free Graft Copolymerization of Maleic Anhydride onto Cellulose Acetate Butyrate Bioplastic by Reactive ExtrusionMACROMOLECULAR MATERIALS & ENGINEERING, Issue 1 2006Arief C. Wibowo Abstract Summary: Interfacial adhesion between fibers and matrix is a crucial factor for effective stress transfer from matrix to fiber; especially in short fiber reinforced composite systems. The use of a chemical compatibilizer is an efficient means to achieve such adhesion. Maleic anhydride-grafted-cellulose acetate butyrate (CAB-g-MA) is one such compatibilizer which can be used in biocomposite fabrication, and this has been synthesized in our laboratory by utilizing a twin-screw reactive extrusion process in the presence of a free radical initiator (2,5-dimethyl-2,5-di(tert -butylperoxy)hexane). The unique feature of this process is its solvent-free approach for grafting of maleic anhydride onto CAB, without hydroxyl group protection. CAB-g-MA was characterized using FTIR as well as by a non-aqueous titration method. The effects of initiator and monomer concentrations and various processing conditions on the graft content were also investigated. The preliminary results show that by adding approximately 10 wt.-% of CAB-g-MA into a plasticized cellulose acetate butyrate (TEB)-industrial hemp fiber biocomposites system, an improvement in tensile strength (20%) and in tensile modulus (45%) were obtained. These results are promising in that they pave the way for future studies involving the use of CAB-g-MA as a suitable compatibilizer for cellulose ester-natural fiber biocomposites. [source] Additive angle method for fast large-tip-angle RF pulse design in parallel excitationMAGNETIC RESONANCE IN MEDICINE, Issue 4 2008William A. Grissom Abstract Current methods for parallel excitation RF pulse design are based on the small-tip-angle approximation, which provides a computationally efficient means of pulse calculation. In general, pulses designed with those methods are inaccurate when scaled to produce large-tip angles, and methods for large-tipangle pulse design are more computationally demanding. This paper introduces a fast iterative method for large-tip-angle parallel pulse design that is formulated as a small number of Bloch equation simulations and fast small-tip-angle pulse designs, the results of which add to produce large-tip-angle pulses. Simulations and a phantom experiment demonstrate that the method is effective in designingmultidimensional large-tip-angle pulses of high excitation accuracy, compared to pulses designed with small-tip-angle methods. Magn Reson Med 59:779,787, 2008. © 2008 Wiley-Liss, Inc. [source] Evaluating Peer Review in an Introductory Instructional Design CoursePERFORMANCE IMPROVEMENT QUARTERLY, Issue 3 2001Nicholas H. Woolf ABSTRACT A peer review process, in which students reviewed other students' projects in a graduate introductory instructional design course, was evaluated. Peer review was experienced by these students as a learning activity about the process of instructional design (ID). The role of traditional ID models in representing ID as overly procedural-ized was mitigated, and the value, inter-personal processes, and affective aspects of formative evaluation were recognized. The effectiveness of peer review was influenced by the culture of the course in which it was embedded and by the structure of the process itself. Peer review is proposed as an authentic and efficient means to introduce graduate students to the strategic knowledge needed to apply ID skills. Recommendations are made to increase the effectiveness of peer review. [source] Instructional Design and Powerful LearningPERFORMANCE IMPROVEMENT QUARTERLY, Issue 2 2001Gordon Rowland ABSTRACT Skillfully executed, instructional design can result in effective and efficient means to meet learning goals. However, more powerful learning experiences seem to go beyond effectiveness, efficiency, appeal, and even predetermined goals. This study sought to identify the key features of instructional design, to determine the nature of powerful learning experiences, and to explore how the two might relate. A survey of experts and a series of interviews with adult learners revealed overlap in some areas, for example, in the perceived importance of active engagement in authentic situations, and clear differences in others, most significantly the importance placed by learners on continual face-to-face personal interaction with a mentor/expert teacher. Speculations are offered on what similar results from additional studies might imply with regard to design actions and choices, and questions for further research are posed. [source] Crystal structure of the antibiotic albomycin in complex with the outer membrane transporter FhuAPROTEIN SCIENCE, Issue 5 2000Andrew D. Ferguson Abstract One alternative method for drug delivery involves the use of siderophore-antibiotic conjugates. These compounds represent a specific means by which potent antimicrobial agents, covalently linked to iron-chelating siderophores, can be actively transported across the outer membrane of Gram-negative bacteria. These "Trojan Horse" antibiotics may prove useful as an efficient means to combat multi-drug,resistant bacterial infections. Here we present the crystallo-graphic structures of the natural siderophore-antibiotic conjugate albomycin and the siderophore phenylferricrocin, in complex with the active outer membrane transporter FhuA from Escherichia coli. To our knowledge, this represents the first structure of an antibiotic bound to its cognate transporter. Albomycins are broad-host range antibiotics that consist of a hydroxamate-type iron-chelating siderophore, and an antibiotically active, thioribosyl pyrimidine moiety. As observed with other hydroxamate-type siderophores, the three-dimensional structure of albomycin reveals an identical coordination geometry surrounding the ferric iron atom. Unexpectedly, this antibiotic assumes two conformational isomers in the binding site of FhuA, an extended and a compact form. The structural information derived from this study provides novel insights into the diverse array of antibiotic moieties that can be linked to the distal portion of iron-chelating siderophores and offers a structural platform for the rational design of hydroxamate-type siderophore-antibiotic conjugates. [source] Democratic Governance: Systems and Radical PerspectivesPUBLIC ADMINISTRATION REVIEW, Issue 3 2006Mark Bevir How might we think about democratic governance? This paper distinguishes between system governance and radical democracy. System governance borrows the language of radical democracy while missing its spirit. It advocates increased participation through networks because new institutionalists suggest networks are an efficient means of service delivery. It advocates increased consultation to build consensus because communitarians suggest consensus is needed for effective political institutions. System governance is, then, a top-down discourse based on the alleged expertise of social scientists. Radical democrats concentrate instead on the self-government of citizens. Instead of the incorporation of established groups in networks, they promote a pluralism within which aspects of governance are handed over to associations in civil society. And instead of consultation prior to decision making, they promote a dialogue in which citizens play an active role in making and implementing public policy. [source] Isomer differentiation by combining gas chromatography, selective self-ion/molecule reactions and tandem mass spectrometry in an ion trap mass spectrometerRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 10 2003Hui-Fen Wu This study presents a novel, simple and rapid procedure for isomer differentiation by combining gas chromatography (GC), a selective self-ion/molecule reaction (SSIMR) and tandem mass spectrometry (MS/MS) in an ion trap mass spectrometer (ITMS). SSIMR product ions were produced from four isomers. For aniline, SSIMR induces the formation of the molecular ion, [M+H]+, [M+CH]+, adduct ions of fragments ([M+F]+, where F represents fragment ions) and [2MH]+. 2 and 3-Picoline produce [M+H]+, [2MH]+ and [M+F]+, while 5-hexynenitrile produces [M+H]+, [M+F]+ and [2M+H]+ ions. The proposed method provides a relatively easy, rapid and efficient means of isomer differentiation via a SSIMR in the ITMS. Typically, isomer differentiation can be achieved within several minutes. The superiority of the SSIMR technique for isomer differentiation over electronic ionization (EI) is also demonstrated. Copyright © 2003 John Wiley & Sons, Ltd. [source] RNA-containing adenovirus/polyethylenimine transfer complexes effectively transduce dendritic cells and induce antigen-specific T cell responsesTHE JOURNAL OF GENE MEDICINE, Issue 4 2004Tatjana C. Gust Abstract Background Dendritic cells (DCs) are the most potent antigen-presenting cells in initiating primary immune responses. Given the unique properties of DCs, gene-modified DCs represent a particularly attractive approach for immunotherapy of diseases such as cancer. Methods Gene-modified DCs were obtained by a receptor-mediated gene delivery system using adenovirus (Ad) particles as ligand and RNA or DNA condensed by polyethylenimine (PEI). In vitro transcribed polyadenylated or non-polyadenylated RNA was used. RNA-transduced DCs were generated expressing chicken ovalbumin (OVA) or chimeric constructs thereof, and compared with DNA-transduced DCs. Results Ad/PEI transfection complexes efficiently delivered RNA into DCs. Such RNA-transduced DCs induced OVA-specific T cell responses more effectively than DNA-transduced DCs. Furthermore, DCs transduced with polyadenylated RNA were more potent in stimulating CD4+ and CD8+ T cell responses than DCs transduced with non-polyadenylated RNA and this was particularly important for CD4+ T cell responses. Conclusions Ad/PEI/RNA transfection is an efficient means for generating RNA-transduced DCs and for stimulating antigen-specific T cell responses. Polyadenylation of RNA enhances CD8+ T cell responses and is essential for CD4+ T cell responses. Copyright © 2004 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||