Science.gov

Sample records for current construction activities

  1. Space construction activities

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Center for Space Construction at the University of Colorado at Boulder was established in 1988 as a University Space Engineering Research Center. The mission of the Center is to conduct interdisciplinary engineering research which is critical to the construction of future space structures and systems and to educate students who will have the vision and technical skills to successfully lead future space construction activities. The research activities are currently organized around two central projects: Orbital Construction and Lunar Construction. Summaries of the research projects are included.

  2. Girls' Bodily Activities in Physical Education How Current Fitness and Sport Discourses Influence Girls' Identity Construction

    ERIC Educational Resources Information Center

    Walseth, Kristin; Aartun, Iselin; Engelsrud, Gunn

    2017-01-01

    Girls' identity constructions are influenced by the dominant sport, health and beauty discourses in their society. Recent research indicates that sport and health discourses embedded in physical education (PE) compete for influence. Some of these studies have illustrated how these discourses inform girls' social construction of body ideals and…

  3. PARTICULATE EMISSIONS FROM CONSTRUCTION ACTIVITIES

    EPA Science Inventory

    Although it has long been recognized that road and building construction activity constitutes an important source of PM emissions throughout the United States, until recently only limited research has been directed to its characterization. This paper presents the results of PM10...

  4. PARTICULATE EMISSIONS FROM CONSTRUCTION ACTIVITIES

    EPA Science Inventory

    Although it has long been recognized that road and building construction activity constitutes an important source of PM emissions throughout the United States, until recently only limited research has been directed to its characterization. This paper presents the results of PM10...

  5. Particulate emissions from construction activities.

    PubMed

    Muleski, Gregory E; Cowherd, Chatten; Kinsey, John S

    2005-06-01

    Although it has long been recognized that road and building construction activity constitutes an important source of particulate matter (PM) emissions throughout the United States, until recently only limited research has been directed to its characterization. This paper presents the results of PM10 and PM2.5 (particles < or = 10 microm and < or = 2.5 microm in aerodynamic diameter, respectively) emission factor development from the onsite testing of component operations at actual construction sites during the period 1998-2001. Much of the testing effort was directed at earthmoving operations with scrapers, because earthmoving is the most important contributor of PM emissions across the construction industry. Other sources tested were truck loading and dumping of crushed rock and mud and dirt carryout from construction site access points onto adjacent public paved roads. Also tested were the effects of watering for control of scraper travel routes and the use of paved and graveled aprons at construction site access points for reducing mud and dirt carryout. The PM10 emissions from earthmoving were found to be up to an order of magnitude greater than predicted by AP-42 emission factors drawn from other industries. As expected, the observed PM2.5:PM10 emission factor ratios reflected the relative importance of the vehicle exhaust and the resuspended dust components of each type of construction activity. An unexpected finding was that PM2.5 emissions from mud and dirt carryout were much less than anticipated. Finally, the control efficiency of watering of scraper travel routes was found to closely follow a bilinear moisture model.

  6. Mobile Libraries, Design and Construction: A Survey of Current Practice.

    ERIC Educational Resources Information Center

    Eastwood, C. R.; And Others

    Forty-one country libraries in Wales, Scotland and England were surveyed in 1970 in an attempt to establish current practice in the design and construction of mobile libraries. This report is the first step of the Branch and Mobile Libraries Group of the Library Association to establish standards for mobile library design and construction. The…

  7. Twistor-inspired construction of electroweak vector boson currents

    NASA Astrophysics Data System (ADS)

    Bern, Zvi; Forde, Darren; Kosower, David A.; Mastrolia, Pierpaolo

    2005-07-01

    We present an extension of the twistor-motivated MHV vertices and accompanying rules presented by Cachazo, Svrček and Witten to the construction of vector-boson currents coupling to an arbitrary source. In particular, we give rules for constructing off-shell vector-boson currents with one fermion pair and n gluons of arbitrary helicity. These currents may be employed directly in the computation of electroweak amplitudes. The rules yield expressions in agreement with previously-obtained results for Z,W,γ*→q¯q+n gluons (analytically up to n=3, beyond via the Berends-Giele recursion relations). We also confirm that the contribution to a seven-point amplitude containing the nonabelian triple vector-boson coupling obtained using the next-to-MHV currents matches the previous result in the literature.

  8. Chinese Children's Constructive Activity and Text Comprehension

    ERIC Educational Resources Information Center

    Law, Yin-Kum

    2008-01-01

    This study investigated how constructive activities are involved when Chinese students are performing reading tasks that require deeper levels of understanding. Forty students from Grade 5 (19 boys and 21 girls), and 42 students from Grade 6 (20 boys and 22 girls) participated in this study. To reveal the children's constructive processes in…

  9. Current trends in health facility planning, design, and construction.

    PubMed

    Beale, Craig; Kittredge, Frank D

    2014-01-01

    It is critical now more than ever for today's healthcare facilities to serve as more than just a backdrop to the care provided--they can, and should, be an integral part of that care. In addition to promoting efficacy, delighting the senses, and placing patients and families at ease, facilities need to be high-performing, sustainable, and healthy environments. Creating today's healthcare facilities requires breaking through barriers in unexpected ways, and it often requires looking outside the healthcare profession for guidance. In this article, we explore current trends in health facility planning, design, and construction. Our focus is on the buildings that serve as venues for the provision of healthcare services across the full continuum, from prevention to critical care. In particular, we discuss four current broad trends and conclude with thoughts on future developments.

  10. Wakimoto realizations of current algebras: an explicit construction

    SciTech Connect

    de Boer, Jan; Feher, Laszlo

    1996-11-12

    A generalized Wakimoto realization of $\\widehat\\cal G_K$ can be associated with each parabolic subalgebra $\\cal P=(\\cal G_0 +\\cal G_+)$ of a simple Lie algebra $\\cal G$ according to an earlier proposal by Feigin and Frenkel. In this paper the proposal is made explicit by developing the construction of Wakimoto realizations from a simple but unconventional viewpoint. An explicit formula is derived for the Wakimoto current first at the Poisson bracket level by Hamiltonian symmetry reduction of the WZNW model. The quantization is then performed by normal ordering the classical formula and determining the required quantum correction for it to generate $\\widehat\\cal G_K$ by means of commutators. The affine-Sugawara stress-energy tensor is verified to have the expected quadratic form in the constituents, which are symplectic bosons belonging to $\\cal G_+$ and a current belonging to $\\cal G_0$. The quantization requires a choice of special polynomial coordinates on the big cell of the flag manifold $P\\backslash G$. The effect of this choice is investigated in detail by constructing quantum coordinate transformations. Finally, the explicit form of the screening charges for each generalized Wakimoto realization is determined, and some applications are briefly discussed.

  11. Current-reinforced random walks for constructing transport networks

    PubMed Central

    Ma, Qi; Johansson, Anders; Tero, Atsushi; Nakagaki, Toshiyuki; Sumpter, David J. T.

    2013-01-01

    Biological systems that build transport networks, such as trail-laying ants and the slime mould Physarum, can be described in terms of reinforced random walks. In a reinforced random walk, the route taken by ‘walking’ particles depends on the previous routes of other particles. Here, we present a novel form of random walk in which the flow of particles provides this reinforcement. Starting from an analogy between electrical networks and random walks, we show how to include current reinforcement. We demonstrate that current-reinforcement results in particles converging on the optimal solution of shortest path transport problems, and avoids the self-reinforcing loops seen in standard density-based reinforcement models. We further develop a variant of the model that is biologically realistic, in the sense that the particles can be identified as ants and their measured density corresponds to those observed in maze-solving experiments on Argentine ants. For network formation, we identify the importance of nonlinear current reinforcement in producing networks that optimize both network maintenance and travel times. Other than ant trail formation, these random walks are also closely related to other biological systems, such as blood vessels and neuronal networks, which involve the transport of materials or information. We argue that current reinforcement is likely to be a common mechanism in a range of systems where network construction is observed. PMID:23269849

  12. Risk compensation behaviours in construction workers' activities.

    PubMed

    Feng, Yingbin; Wu, Peng

    2015-01-01

    The purpose of this study was to test whether the construction workers have the tendency of engaging in risk compensation behaviours, and identify the demographic variables, which may influence the extent to which the construction workers may show risk compensation behaviours. Both quantitative (survey) and qualitative (interviews) approaches were used in this study. A questionnaire survey was conducted with all the construction workers on three building construction sites of a leading construction company in Australia. Semi-structured interviews were then conducted to validate the findings of the quantitative research. The findings indicate that workers tend to show risk compensation behaviours in the construction environment. The workers with more working experience, higher education, or having never been injured at work before have a higher tendency to show risk compensation in their activities than the others. The implication is that contractors need to assess the potential influence of workers' risk compensation behaviours when evaluating the effect of risk control measures. It is recommended that supervisors pay more attention to the behavioural changes of those workers who have more experience, higher education, and have never been injured before after the implementation of new safety control measures on construction site.

  13. Comprehension of Architectural Construction through Multimedia Active Learning

    ERIC Educational Resources Information Center

    Mas, Ángeles; Blasco, Vicente; Lerma, Carlos; Angulo, Quiteria

    2013-01-01

    This study presents an investigation about the use of multimedia procedures applied to architectural construction teaching. We have applied current technological resources, aiming to rationalize and optimize the active learning process. The experience presented to students is very simple and yet very effective. It has consisted in a simulation of…

  14. Activity measurements of radon from construction materials.

    PubMed

    Fior, L; Nicolosi Corrêa, J; Paschuk, S A; Denyak, V V; Schelin, H R; Soreanu Pecequilo, B R; Kappke, J

    2012-07-01

    This work presents the results of radon concentration measurements of construction materials used in the Brazilian industry, such as clay (red) bricks and concrete blocks. The measurements focused on the detection of indoor radon activity during different construction stages and the analysis of radionuclides present in the construction materials. For this purpose, sealed chambers with internal dimensions of approximately 60×60×60 cm3 were built within a protected and isolated laboratory environment, and stable air humidity and temperature levels were maintained. These chambers were also used for radon emanation reduction tests. The chambers were built in four major stages: (1) assembly of the walls using clay (red) bricks, concrete blocks, and mortar; (2) installation of plaster; (3) finishing of wall surface using lime; and (4) insulation of wall surface and finishing using paint. Radon measurements were performed using polycarbonate etched track detectors. By comparing the three layers applied to the masonry walls, it was concluded that only the last step (wall painting using acrylic varnish) reduced the radon emanation, by a factor of approximately 2. Samples of the construction materials (clay bricks and concrete blocks) were ground, homogenized, and subjected to gamma-ray spectrometry analysis to evaluate the activity concentrations of 226Ra, 232Th and 40K. The values for the index of the activity concentration (I), radium equivalent activity (Raeq), and external hazard index (Hext) showed that these construction materials could be used without restrictions or concern about the equivalent dose limit (1 mSv/year). Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Activities of the Center for Space Construction

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Center for Space Construction (CSC) at the University of Colorado at Boulder is one of eight University Space Engineering Research Centers established by NASA in 1988. The mission of the center is to conduct research into space technology and to directly contribute to space engineering education. The center reports to the Department of Aerospace Engineering Sciences and resides in the College of Engineering and Applied Science. The college has a long and successful track record of cultivating multi-disciplinary research and education programs. The Center for Space Construction is prominent evidence of this record. At the inception of CSC, the center was primarily founded on the need for research on in-space construction of large space systems like space stations and interplanetary space vehicles. The scope of CSC's research has now evolved to include the design and construction of all spacecraft, large and small. Within this broadened scope, our research projects seek to impact the underlying technological basis for such spacecraft as remote sensing satellites, communication satellites, and other special purpose spacecraft, as well as the technological basis for large space platforms. The center's research focuses on three areas: spacecraft structures, spacecraft operations and control, and regolith and surface systems. In the area of spacecraft structures, our current emphasis is on concepts and modeling of deployable structures, analysis of inflatable structures, structural damage detection algorithms, and composite materials for lightweight structures. In the area of spacecraft operations and control, we are continuing our previous efforts in process control of in-orbit structural assembly. In addition, we have begun two new efforts in formal approach to spacecraft flight software systems design and adaptive attitude control systems. In the area of regolith and surface systems, we are continuing the work of characterizing the physical properties of lunar

  16. Scene Construction, Visual Foraging, and Active Inference

    PubMed Central

    Mirza, M. Berk; Adams, Rick A.; Mathys, Christoph D.; Friston, Karl J.

    2016-01-01

    This paper describes an active inference scheme for visual searches and the perceptual synthesis entailed by scene construction. Active inference assumes that perception and action minimize variational free energy, where actions are selected to minimize the free energy expected in the future. This assumption generalizes risk-sensitive control and expected utility theory to include epistemic value; namely, the value (or salience) of information inherent in resolving uncertainty about the causes of ambiguous cues or outcomes. Here, we apply active inference to saccadic searches of a visual scene. We consider the (difficult) problem of categorizing a scene, based on the spatial relationship among visual objects where, crucially, visual cues are sampled myopically through a sequence of saccadic eye movements. This means that evidence for competing hypotheses about the scene has to be accumulated sequentially, calling upon both prediction (planning) and postdiction (memory). Our aim is to highlight some simple but fundamental aspects of the requisite functional anatomy; namely, the link between approximate Bayesian inference under mean field assumptions and functional segregation in the visual cortex. This link rests upon the (neurobiologically plausible) process theory that accompanies the normative formulation of active inference for Markov decision processes. In future work, we hope to use this scheme to model empirical saccadic searches and identify the prior beliefs that underwrite intersubject variability in the way people forage for information in visual scenes (e.g., in schizophrenia). PMID:27378899

  17. Silica dust exposures during selected construction activities.

    PubMed

    Flanagan, Mary Ellen; Seixas, Noah; Majar, Maria; Camp, Janice; Morgan, Michael

    2003-01-01

    This study characterized exposure for dust-producing construction tasks. Eight common construction tasks were evaluated for quartz and respirable dust exposure by collecting 113 personal task period samples for cleanup; demolition with handheld tools; concrete cutting; concrete mixing; tuck-point grinding; surface grinding; sacking and patching concrete; and concrete floor sanding using both time-integrating filter samples and direct-reading respirable dust monitors. The geometric mean quartz concentration was 0.10 mg/m(3) (geometric standard deviation [GSD]=4.88) for all run time samples, with 71% exceeding the threshold limit value. Activities with the highest exposures were surface grinding, tuck-point grinding, and concrete demolition (GM[GSD] of 0.63[4.12], 0.22[1.94], and 0.10[2.60], respectively). Factors recorded each minute were task, tool, work area, respiratory protection and controls used, estimated cross draft, and whether anyone nearby was making dust. Factors important to exposure included tool used, work area configuration, controls employed, cross draft, and in some cases nearby dust. More protective respirators were employed as quartz concentration increased, although respiratory protection was found to be inadequate for 42% of exposures. Controls were employed for only 12% of samples. Exposures were reduced with three controls: box fan for surface grinding and floor sanding, and vacuum/shroud for surface grinding, with reductions of 57, 50, and 71%, respectively. Exposures were higher for sweeping compound, box fan for cleanup, ducted fan dilution, and wetted substrate. Construction masons and laborers are frequently overexposed to silica. The usual protection method, respirators, was not always adequate, and engineering control use was infrequent and often ineffective.

  18. Nonuniform discharge currents in active plasma lenses

    NASA Astrophysics Data System (ADS)

    van Tilborg, J.; Barber, S. K.; Tsai, H.-E.; Swanson, K. K.; Steinke, S.; Geddes, C. G. R.; Gonsalves, A. J.; Schroeder, C. B.; Esarey, E.; Bulanov, S. S.; Bobrova, N. A.; Sasorov, P. V.; Leemans, W. P.

    2017-03-01

    Active plasma lenses have attracted interest in novel accelerator applications due to their ability to provide large-field-gradient (short focal length), tunable, and radially symmetric focusing for charged particle beams. However, if the discharge current is not flowing uniformly as a function of radius, one can expect a radially varying field gradient as well as potential emittance degradation. We have investigated this experimentally for a 1-mm-diameter active plasma lens. The measured near-axis field gradient is approximately 35% larger than expected for a uniform current distribution, and at overfocusing currents ring-shaped electron beams are observed. These observations are explained by simulations.

  19. Current Neural and Behavioral Dimensional Constructs across Mood Disorders

    PubMed Central

    Langenecker, Scott A.; Jacobs, Rachel H.; Passarotti, Alessandra M.

    2014-01-01

    Our understanding of the underlying neurobiology for mood disorders is still limited. We present an integrated model for conceptualizing and understanding mood disorders drawing upon a broad literature pertinent to mood disorders. The integrated model of emotion processing and regulation incorporates the linguistic constructs of the Research Domain Criteria (RDoC) initiative. In particular, we focus on the Positive Valence domain/circuit (PVC), highlighting recent reward research and the Negative Valence domain/circuit (NVC), highlighting rumination. Furthermore, we also illustrate the Cognitive Control and Problem Solving (CCaPS) circuit, which is heavily involved in emotion regulation, as well as the default mode network (DMN) and interactions between circuits. We conclude by proposing methods for addressing challenges in the developmental study of mood disorders including using high-risk design that incorporates risk for many disorders. PMID:25147755

  20. Microbial biomass, activity and community composition in constructed wetlands.

    PubMed

    Truu, Marika; Juhanson, Jaanis; Truu, Jaak

    2009-06-15

    The aim of the current article is to give an overview about microbial communities and their functioning but also about factors affecting microbial activity in the three most common types (surface flow and two types of sub-surface flow) of constructed wetlands. The paper reviews the community composition and structural diversity of the microbial biomass, analyzing different aspects of microbial activity with respect to wastewater properties, specific wetland type, and environmental parameters. A brief introduction about the application of different novel molecular techniques for the assessment of microbial communities in constructed wetlands is also given. Microbially mediated processes in constructed wetlands are mainly dependent on hydraulic conditions, wastewater properties, including substrate and nutrient quality and availability, filter material or soil type, plants, and different environmental factors. Microbial biomass is within similar ranges in both horizontal and vertical subsurface flow and surface flow constructed wetlands. Stratification of the biomass but also a stratified structural pattern of the bacterial community can be seen in subsurface flow systems. Microbial biomass C/N ratio is higher in horizontal flow systems compared to vertical flow systems, indicating the structural differences in microbial communities between those two constructed wetland types. The total activity of the microbial community is in the same range, but heterotrophic growth is higher in the subsurface (vertical flow) system compared to the surface flow systems. Available species-specific data about microbial communities in different types of wetlands is scarce and therefore it is impossible make any general conclusions about the dynamics of microbial community structure in wetlands, its relationship to removal processes and operational parameters.

  1. Inferred flows of electric currents in solar active regions

    NASA Technical Reports Server (NTRS)

    Ding, Y. J.; Hong, Q. F.; Hagyard, M. J.; Deloach, A. C.

    1985-01-01

    Techniques to identify sources of major current systems in active regions and their channels of flow are explored. Measured photospheric vector magnetic fields together with high resolution white light and H-alpha photographs provide the data base to derive the current systems in the photosphere and chromosphere of a solar active region. Simple mathematical constructions of active region fields and currents are used to interpret these data under the assumptions that the fields in the lower atmosphere (below 200 km) may not be force free but those in the chromosphere and higher are. The results obtained for the complex active region AR 2372 are: (1) Spots exhibiting significant spiral structure in the penumbral filaments were the source of vertical currents at the photospheric surface; (2) Magnetic neutral lines where the transverse magnetic field was strongly sheared were channels along which a strong current system flowed; (3) The inferred current systems produced a neutral sheet and oppositely-flowing currents in the area of the magnetic delta configuration that was the site of flaring.

  2. PARTICULATE EMISSION MEASUREMENTS FROM CONTROLLED CONSTRUCTION ACTIVITIES

    EPA Science Inventory

    The report summarized the results of field testing of the effectiveness of control measures for sources of fugitive particulate emissions found at construction sites. The effectiveness of watering temporary, unpaved travel surfaces on emissions of particulate matter with aerodyna...

  3. PARTICULATE EMISSION MEASUREMENTS FROM CONTROLLED CONSTRUCTION ACTIVITIES

    EPA Science Inventory

    The report summarized the results of field testing of the effectiveness of control measures for sources of fugitive particulate emissions found at construction sites. The effectiveness of watering temporary, unpaved travel surfaces on emissions of particulate matter with aerodyna...

  4. Current Activities of the ASME Subgroup NUPACK

    SciTech Connect

    Gerald M. Foster; D. Keith Morton; Paul McConnell

    2007-10-01

    Current activities of the American Society of Mechanical Engineers (ASME), Section III Subgroup on Containment Systems for Spent Fuel High-Level Waste Transport Packagings (also known as Subgroup NUPACK) are reviewed with emphasis on the recent revision of Subsection WB. Also, brief insightson new proposals for the development of rules for internal support structures and for a strain-based acceptance criteria are provided.

  5. Current and future offshore activities in Canada

    SciTech Connect

    Hnatiuk, J.

    1984-05-01

    The development of innovative exploratory drilling systems for Canada's harsh Arctic offshore areas over the past decade is described. Future activity in these areas, including possible production concepts, is also discussed. The results of the experience in Canadian waters can be applied in other Arctic areas of the world including offshore Alaska. This operating experience will serve to further advance the drilling technology and will serve as a basis for the design of Arctic offshore production and transportation systems. Artificial islands, first commenced in 1972, are still being constructed but with improved designs and equipment. A step forward has been the use of subsea berms on which concrete or steel segmented caissons have been placed. Integrated-type steel caissons have also been adapted for placement on subsea berms, one of which is half of a crude oil tanker and a second, a purpose-built steel caisson to be placed this summer.

  6. Saturn's Titan: Evidence for Current Cryovolcanic Activity

    NASA Astrophysics Data System (ADS)

    Nelson, Robert M.; Cassini VIMS Titan Surface Variability Group

    2009-09-01

    We report evidence suggesting current cryovolcanic activity on Titan. This is based on surface changes seen at selected locations by the Cassini Visual and Infrared Mapping Spectrometer (VIMS). Titan's surface is hard to observe because Titan's atmosphere is opaque at visual wavelengths due to methane absorption. However, VIMS is able to image the surface at selected infrared wavelengths where the methane is relatively transparent[1,2]. VIMS reported surface reflectance variability at Hotei Arcus (26S,78W) and that the variability might be due to deposition followed by coverage or dissipation of ammonia frost. Subsequently, Cassini RADAR images found that Hotei Arcus has lobate "flow” forms, consistent with the morphology of volcanic terrain [3]. Here we report the discovery of lobate "flow” patterns at Hotei Arcus in VIMS infrared images taken during Cassini close flybys during 2008-2009. These data further suggest that the brightness variability at Hotei Arcus is associated with ammonia, a compound expected in Titan's interior. This, combined with the previous evidence from VIMS and RADAR images, creates a strong case for Titan having a presently active surface, possibly due to cryovolcanism. It has not escaped our attention that gaseous ammonia, in association with methane and nitrogen in Titan's atmosphere, is similar to the terrestrial environment at the time that life first emerged. If Titan is currently active, then these results raise the following questions: What is the full extent of current geologic activity? What are the ongoing processes? Are Titan's chemical processes today supporting a prebiotic chemistry similar to that under which life evolved on Earth? This work done at JPL under contract with NASA. References: [1]R. M. Nelson et al., Icarus 199 (2009) 429-441. [2]R. M. Nelson et al., GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L04202, doi:10.1029/2008GL036206, 2009. [3]S. D. Wall GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L04203, doi:10.1029/2008GL

  7. Railgun current guard plates - Active current management and augmentation

    NASA Astrophysics Data System (ADS)

    Beno, Joseph H.; Weldon, William F.

    1989-06-01

    A system of auxiliary conductors designed to reduce current density peaks in railgun rails is described, and the effects on rail current density and projectile force are discussed. Performance comparisons with simple railguns and typical augmented railguns are made. It is shown that the wrap-around design of the guard plates can produce four to eight times the force produced by the usual augmented railgun design, without increasing local peak current densities. The range of performance contained in the factors between four and eight is primarily a function of the complexity of design. The more complex designs involve allowing the guard plates to overhang the rail slightly (intruding into the bore space, similar to rifling in a conventional gun barrel), and the use of separate power supplies for the rail and guard-plate conductors. These added complexities represent unacceptable complications for many applications, but may be justifiable for others.

  8. 75 FR 4612 - Agency Information Collection Activities: Notice of Request for Extension of Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-28

    ... construction time and traffic congestion; C. The development of engineering design criteria for innovative... Federal Highway Administration Agency Information Collection Activities: Notice of Request for Extension of Currently Approved Information Collection AGENCY: Federal Highway Administration (FHWA),...

  9. Student Constructions of "Active Citizenship": What Does Participation Mean to Students?

    ERIC Educational Resources Information Center

    Kennedy, Kerry J.

    2007-01-01

    "Active citizenship" is currently a popular term in citizenship education policy discourse. Despite this policy interest, there is no agreement about the meaning of "active citizenship". This article draws on data from the IEA Civic Education Study to explore how students themselves construct "active citizenship". The results show that students…

  10. Student Constructions of "Active Citizenship": What Does Participation Mean to Students?

    ERIC Educational Resources Information Center

    Kennedy, Kerry J.

    2007-01-01

    "Active citizenship" is currently a popular term in citizenship education policy discourse. Despite this policy interest, there is no agreement about the meaning of "active citizenship". This article draws on data from the IEA Civic Education Study to explore how students themselves construct "active citizenship". The results show that students…

  11. Pederson Current Dissipation In Emerging Active Regions

    NASA Astrophysics Data System (ADS)

    Leake, James E.; Linton, M. G.

    2011-05-01

    Pederson current dissipation in emerging active regions. Certain regions of the solar atmosphere, such as the photosphere and chromosphere, as well as prominences, contain a significant amount of neutral atoms, and a complete description of the plasma requires including the effects of partial ionization. In the chromosphere the dissipation of Pederson currents is important for the evolution of emerging magnetic fields. Due to the relatively high number density in the chromosphere, the ion-neutral collision time-scale is much smaller than timescales associated with flux emergence. Hence we use a single-fluid approach to model the partially ionized plasma. Looking at both the emergence of large-scale sub-surface structures, and the emergence and reconnection of undulatory fields, we investigate the effect of Pederson current dissipation on the state of the emerging field, on magnetic reconnection and on dissipative heating of the atmosphere. Specifically we examine the effect of motions across fieldlines in the partially ionized regions, and how this can increase the free energy supplied to the corona by flux emergence. We also look at reconnection associated with flux emergence in the partially ionized atmosphere, and how this can account for observed small-scale brightenings (Ellerman Bombs).

  12. Current Helicity of Emerging Active Regions

    NASA Astrophysics Data System (ADS)

    Pevtsov, A.

    2002-12-01

    We employ the SOHO MDI magnetograms and EIT images to study evolution of current helicity of solar active regions during early stages of their emergence. Using longitudinal magnetograms we compute linear force-free fields ∇ x B = α B and compare extrapolated field lines with bright coronal structures to constrain the value of α. At the beginning of emergence all studied regions have small α ~eq 0. As active region grows, α gradually increases and reaches a "plateau" within approximately one day of emergence. Using change in separation between negative and positive fluxes, we divide regions on "slow" and "rapid" emergence. Three regions show "slow" (> 1 day) emergence. For these regions α increases faster than the separation. In two "rapid" (< 1 day) emerging regions α grows slower that the separation. This observed evolution of current helicity is in agreement with Longcope and Welsch (2000) model of emergence of subphotospheric twisted flux rope into the corona. škip 0.5 truecm V. Maleev is NSO 2002 Summer Research Assistant from St. Petersburg State University, Russia

  13. Alternating Current Influences Anaerobic Electroactive Biofilm Activity.

    PubMed

    Wang, Xin; Zhou, Lean; Lu, Lu; Lobo, Fernanda Leite; Li, Nan; Wang, Heming; Park, Jaedo; Ren, Zhiyong Jason

    2016-09-06

    Alternating current (AC) is known to inactivate microbial growth in suspension, but how AC influences anaerobic biofilm activities has not been systematically investigated. Using a Geobacter dominated anaerobic biofilm growing on the electrodes of microbial electrochemical reactors, we found that high frequency AC ranging from 1 MHz to 1 kHz (amplitude of 5 V, 30 min) showed only temporary inhibition to the biofilm activity. However, lower frequency (100 Hz, 1.2 or 5 V) treatment led to 47 ± 19% permanent decrease in limiting current on the same biofilm, which is attributed to the action of electrohydrodynamic force that caused biofilm damage and loss of intercellular electron transfer network. Confocal microscopy images show such inactivation mainly occurred at the interface between the biofilm and the electrode. Reducing the frequency further to 1 Hz led to water electrolysis, which generated gas bubbles that flushed all attached cells out of the electrode. These findings provide new references on understanding and regulating biofilm growth, which has broader implications in biofouling control, anaerobic waste treatment, energy and product recovery, and general understanding of microbial ecology and physiology.

  14. Construct validity-Current issues and recommendations for future hand hygiene research.

    PubMed

    Neo, Jun Rong Jeffrey

    2017-03-10

    Health care-associated infection is a leading cause of morbidity and mortality. Hand hygiene is widely regarded as an effective prevention strategy. Often, hand hygiene research is designed and conducted by health care practitioners who may lack formal training in research methods, particularly in the area of social science. In a research context, a construct is a concept that can be measured or observed in some way. A construct can be directly or indirectly measured. For example, height can be directly measured by centimeters, whereas depression can be indirectly measured by a scale of 20 items. Every construct needs to be operationalized by measure(s) to make it a variable. Hence, construct validity refers to the degree of fit between the construct of interest and its operational measure. However, issues with construct validity often weaken the translation from construct to measure(s). This article will (1) describe the common threats to construct validity pertaining to hand hygiene research, (2) identify practical limitations in current research design, and (3) provide recommendations to improve construct validity in future hand hygiene research. By understanding how construct validity may affect hand hygiene research design, there is great potential to improve the validity of future hand hygiene research findings.

  15. GIS interoperability: current activities and military implications

    NASA Astrophysics Data System (ADS)

    Lam, Sylvia

    1997-07-01

    Geographic information systems (GIS) are gaining importance in military operations because of their capability to spatially and visually integrate various kinds of information. In an era of limited resources, geospatial data must be shared efficiently whenever possible. The military-initiated Global Geospatial Information and Services (GGI&S) Project aims at developing the infrastructure for GIS interoperability for the military. Current activities in standardization and new technology have strong implications on the design and development of GGI&S. To facilitate data interoperability at both the national and international levels, standards and specifications in geospatial data sharing are being studied, developed and promoted. Of particular interest to the military community are the activities related to the NATO DIGEST, ISO TC/211 Geomatics standardization and the industry-led Open Geodata Interoperability Specifications (OGIS). Together with new information technology, standardization provides the infrastructure for interoperable GIS for both civilian and military environments. The first part of this paper describes the major activities in standardization. The second part presents the technologies developed at DREV in support of the GGI&S. These include the Open Geospatial Datastore Interface (OGDI) and the geospatial data warehouse. DREV has been working closely with Defence Geomatics and private industry in the research and development of new technology for the GGI&S project.

  16. Construction of Effective Electromagnetic Currents for Two-Body Quasipotential Equations

    SciTech Connect

    Krioukov, Dmitri

    1998-09-01

    A systematic algebraic approach for the construction of effective electro-magnetic currents consistent with relativistic two-body quasipotential equations is presented. This approach generalizes the Mandelstam formalism and applies it to a generic quasipotential reduction method. The use of Ward-Takahashi identities for the effective currents guarantees conservation of current matrix elements involving any combination of bound and scattering states. This approach is shown to reproduce previous results for current matrix elements for the particular cases of the Gross and Blankenbecler-Sugar equations. A generic method of truncation of the quasipotential effective current with respect to the number of boson exchanges is introduced.

  17. Constructing arabinofuranosidases for dual arabinoxylan debranching activity.

    PubMed

    Wang, Weijun; Andric, Nikola; Sarch, Cody; Silva, Bruno Teixeira; Tenkanen, Maija; Master, Emma R

    2017-09-04

    Enzymatic conversion of arabinoxylan requires α-L-arabinofuranosidases able to remove α-L-arabinofuranosyl residues (α-L-Araf) from both mono- and double-substituted D-xylopyranosyl residues (Xylp) in xylan (i.e., AXH-m and AXH-d activity). Herein, SthAbf62A (a family GH62 α-L-arabinofuranosidase with AXH-m activity) and BadAbf43A (a family GH43 α-L-arabinofuranosidase with AXH-d3 activity), were fused to create SthAbf62A-BadAbf43A and BadAbf43A-SthAbf62A. Both fusion enzymes displayed dual AXH-m,d and synergistic activity towards native, highly branched wheat arabinoxylan (WAX). When using a customized arabinoxylan substrate comprising mainly α-(1→3)-L-Araf and α-(1→2)-L-Araf substituents attached to disubstituted Xylp (d-2,3-WAX), the specific activity of the fusion enzymes was twice that of enzymes added as separate proteins. Moreover, the SthAbf62A-BadAbf43A fusion removed 83% of all α-L-Araf from WAX after a 20 h treatment. (1) H NMR analyses further revealed differences in SthAbf62A-BadAbf43 rate of removal of specific α-L-Araf substituents from WAX, where 9.4 times higher activity was observed towards d-α-(1→3)-L-Araf compared to m-α-(1→3)- L-Araf positions. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  18. 2. General view of Mormon Flat looking upstream. Construction activity ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. General view of Mormon Flat looking upstream. Construction activity is visible at center right. Photographer unknown, September 30, 1923. Source: Salt River Project. - Mormon Flat Dam, On Salt River, Eastern Maricopa County, east of Phoenix, Phoenix, Maricopa County, AZ

  19. Constructing, Perceiving, and Maintaining Scenes: Hippocampal Activity and Connectivity

    PubMed Central

    Zeidman, Peter; Mullally, Sinéad L.; Maguire, Eleanor A.

    2015-01-01

    In recent years, evidence has accumulated to suggest the hippocampus plays a role beyond memory. A strong hippocampal response to scenes has been noted, and patients with bilateral hippocampal damage cannot vividly recall scenes from their past or construct scenes in their imagination. There is debate about whether the hippocampus is involved in the online processing of scenes independent of memory. Here, we investigated the hippocampal response to visually perceiving scenes, constructing scenes in the imagination, and maintaining scenes in working memory. We found extensive hippocampal activation for perceiving scenes, and a circumscribed area of anterior medial hippocampus common to perception and construction. There was significantly less hippocampal activity for maintaining scenes in working memory. We also explored the functional connectivity of the anterior medial hippocampus and found significantly stronger connectivity with a distributed set of brain areas during scene construction compared with scene perception. These results increase our knowledge of the hippocampus by identifying a subregion commonly engaged by scenes, whether perceived or constructed, by separating scene construction from working memory, and by revealing the functional network underlying scene construction, offering new insights into why patients with hippocampal lesions cannot construct scenes. PMID:25405941

  20. Current Practices in the Construction of State Courses of Study. Bulletin, 1931, No. 4

    ERIC Educational Resources Information Center

    Langvick, Mina M.

    1931-01-01

    The purpose of this study is to analyze current practices in the construction of State courses of study. Available State courses of study, reports of survey commissions and educational officials, and other State educational publications have been examined to discover the problems considered significant by State educational officials and the…

  1. Constructive Metacognitive Activity Shift in Mathematical Problem Solving

    ERIC Educational Resources Information Center

    Hastuti, Intan Dwi; Nusantara, Toto; Subanji; Susanto, Hery

    2016-01-01

    This study aims to describe the constructive metacognitive activity shift of eleventh graders in solving a mathematical problem. Subjects in this study were 10 students in grade 11 of SMAN 1 Malang. They were divided into 4 groups. Three types of metacognitive activity undertaken by students when completing mathematical problem are awareness,…

  2. Residential Construction. Technology Learning Activity. Teacher Edition. Technology Education Series.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This packet of technology learning activity (TLA) materials for residential construction for students in grades 6-10 consists of an instructor's section and student materials. The instructor's section contains background information, suggested activities, and a list of suggested resources. A lesson plan for the 10-day module includes assignments;…

  3. Enzyme and root activities in surface-flow constructed wetlands.

    PubMed

    Kong, Ling; Wang, Yu-Bin; Zhao, Li-Na; Chen, Zhang-He

    2009-07-01

    Sixteen small-scale wetlands planted with four plant species were constructed for domestic wastewater purification. The objective of this study was to determine the correlations between contaminant removal and soil enzyme activity, root activity, and growth in the constructed wetlands. The results indicated that correlations between contaminant removal efficiency and enzyme activity varied depending on the contaminants. The removal efficiency of NH4+ was significantly correlated with both urease and protease activity in all wetlands, and the removal of total phosphorus and soluble reactive phosphorus was significantly correlated with phosphatase activity in most wetlands, while the removal of total nitrogen, NO3(-) , and chemical oxygen demand (COD) was significantly correlated with enzyme activity only in a few instances. Correlations between soil enzyme activity and root activity varied among species. Activities of all enzymes were significantly correlated with root activity in Vetiveria zizanioides and Phragmites australis wetlands, but not in Hymenocallis littoralis wetlands. Significant correlations between enzyme activity and root biomass and between enzyme activity and root growth were found mainly in Cyperus flabelliformis wetlands. Root activity was significantly correlated with removal efficiencies of all contaminants except NO3(-) and COD in V. zizanioides wetlands. Enzyme activities and root activity showed single-peak seasonal patterns. Activities of phosphatase, urease, and cellulase were significantly higher in the top layer of the substrate than in the deeper layers, and there were generally no significant differences between the deeper layers (deeper than 15 cm).

  4. Examining the construct validity of affective judgments of physical activity measures.

    PubMed

    Chmielewski, Michael; Sala, Margarita; Tang, Rui; Baldwin, Austin

    2016-09-01

    Affective judgments of physical activity have emerged as important predictors of physical activity and interventions targeting affective judgments are a promising approach to improving regular physical activity. Currently, measures assessing a variety of potentially distinct constructs are treated as interchangeable assessments of affective judgments of physical activity. Moreover, little is known about the construct validity of the purported measures of this construct. We review several components of construct validity; highlighting their importance for health psychology research. Then, we examine the construct validity of a wide variety of affective judgment of physical activity measures in MTurk and student samples. Cronbach's alpha for the included measures was uniformly high; however, several scales contained excessively redundant items that ultimately lessen their construct validity. Moreover, dependability estimates for the majority of measures was poor, indicating high levels of transient measurement error. The included measures significantly predicted levels of physical activity; however, their relative predictive power was strongly associated with their dependability. In general, the affective judgment measures demonstrated poor convergent validity suggesting they are not interchangeable and best viewed as assessing distinct, albeit related, constructs. Another important limitation of these measures is that they exhibited poor discriminant validity from exercise self-efficacy, which represents an important theoretical and empirical issue for the field of health behavior research. Overall, the current findings indicate the available affective judgments of physical activity measures are suboptimal, have considerable construct validity limitations, and thereby prevent the further advancement of science, theory, and intervention development in this promising area of research. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  5. Contingency planning and emergency response in construction activities: Training the construction worker

    SciTech Connect

    Jones, E.

    1987-01-01

    Construction activities have the potential for environmental and/or health impacts at Oak Ridge National Laboratory (ORNL) particularly as site cleanup and restoration plans are initiated. ORNL has instituted special training for all construction workers and related contractors. Individuals learn how construction activities at ORNL can potentially have adverse effects on the environment and their health, and to learn how to respond to potential chemical and radiation hazards. Workers are given a review of basic information on radiation and chemicals in a framework that emphasizes the situations in which workers or the environment may be exposed to potential risk. Specific instructions are presented on what to do when contamination is suspected, with identification of emergency procedures and response personnel. 5 refs., 1 fig.

  6. Active Debris Removal: Current Status of Activities in CNES

    NASA Astrophysics Data System (ADS)

    Bonnal, Christophe; Ruault, Jean-Marc; Desjean, Marie-Christine

    2013-08-01

    Most of the ongoing studies led at worldwide level, mainly through IADC Actions, conclude that in order to keep a stable Low Earth Orbit environment in the coming decades, it may be necessary to retrieve some 5 to 10 large objects annually. These operations, known as Active Debris Removal (ADR), raise a huge amount of difficulties in numerous domains: political, legal, insurance, defense, financing and, last but not least, technical questions. The current paper aims at reviewing the current status of the ADR activities led by CNES both at National and Multi-lateral level. The first question which is raised is that of the high level requirements to be applied. What are the requirements coming from the operators; do we want to stabilize the environment, decrease it or could we accept some increase over the years; when do we have to act; can we baseline random reentry of such large objects or do we have to stick to controlled destructive reentries?… There may not yet be clear answers to these points, so efforts at international level are required. The second part of the paper deals with the potential solutions at system level. Numerous possibilities can be identified, depending on the size of the launcher and of the strategy selected to de-orbit the debris. Large space tugs visiting some 10 debris or small dedicated chasers launched as piggyback are among the solutions which have been traded. The currently preferred solution is described in details. The third part of the paper is devoted to the chaser-debris operations themselves, following five key functions; - the long range rendezvous, - the short range rendezvous up to contact, - the mechanical interfacing of the debris, - its control by the chaser, when required, - the de-orbiting maneuver itself. For each of these functions, the current status of available technologies is described, enabling the identification of the most critical ones requiring additional R&T effort and subsequent demonstrations. Among them

  7. Sailing toward Understanding Surface Currents: A Science and Geography Integration Activity for Upper-Elementary Students

    ERIC Educational Resources Information Center

    Eidietis, Laura; Rutherford, Sandra

    2009-01-01

    In the activities presented in this article, students mimic real scientists while constructing predictions and scientific explanations about surface currents. The activities are inspired by and couched within true scientific inquiries regarding the ocean and the North American Great Lakes. Students engage in a classroom inquiry and use map-reading…

  8. Sailing toward Understanding Surface Currents: A Science and Geography Integration Activity for Upper-Elementary Students

    ERIC Educational Resources Information Center

    Eidietis, Laura; Rutherford, Sandra

    2009-01-01

    In the activities presented in this article, students mimic real scientists while constructing predictions and scientific explanations about surface currents. The activities are inspired by and couched within true scientific inquiries regarding the ocean and the North American Great Lakes. Students engage in a classroom inquiry and use map-reading…

  9. Chaos as a psychological construct: historical roots, principal findings, and current growth directions.

    PubMed

    Guastello, Stephen J

    2009-07-01

    The landmarks in the use of chaos and related constructs in psychology were entwined with the growing use of other nonlinear dynamical constructs, especially catastrophes and self-organization. The growth in substantive applications of chaos in psychology is partially related to the development of methodologies that work within the constraints of psychological data. The psychological literature includes rigorous theory with testable propositions, lighter-weight metaphorical uses of the construct, and colloquial uses of "chaos" with no particular theoretical intent. The current state of the chaos construct and supporting empirical research in psychological theory is summarized in neuroscience, psychophysics, psychomotor skill and other learning phenomena, clinical and abnormal psychology, and group dynamics and organizational behavior. Trends indicate that human systems do not remain chaotic indefinitely; they eventually self-organize, and the concept of the complex adaptive system has become prominent. Chaotic turbulence is generally higher in healthy systems compared to unhealthy systems, although opposite appears true in mood disorders. Group dynamics research shows trends consistent with the complex adaptive system, whereas organizational behavior lags behind in empirical studies relative to the quantity of its theory. Future directions for research involving the chaos construct and other nonlinear dynamics are outlined.

  10. Investigation of a staged plasma-focus apparatus. [pinch construction and current sheet dynamics investigation

    NASA Technical Reports Server (NTRS)

    Lee, J. H.; Mcfarland, D. R.; Harries, W. L.

    1978-01-01

    A new staged plasma-focus geometry combining two Mather-type plasma-focus guns was constructed, and the current-sheet dynamics were investigated. The production of simultaneous pairs of plasma foci was achieved. The intensities of X-ray and fusion-neutron emission were measured and found to agree with the scaling law for a plasma focus. Advantages of this new geometry include the possibility of using plasma-focus type pinches in multiple arrays at power levels beyond the validity regime of the current scaling law for a single gun.

  11. Current experimental activities for solid breeder development

    SciTech Connect

    Johnson, C.E.; Hollenberg, G.W.; Roux, N.; Watanabe, H.

    1988-01-01

    The current data base for ceramic breeder materials does not exhibit any negative features as regards to thermophysical, mechanical, and irradiation behavior. All candidate materials show excellent stability for irradiation testing to 3% burnup. In-situ tritium recovery tests show very low tritium inventories for all candidates. Theoretical models are being developed to accurately predict real time release rates. Fabrication of kilogram quantities of materials has been achieved and technology is available for further scale-up.

  12. Infection control considerations during construction activities: land excavation and demolition.

    PubMed

    Cheng, S M; Streifel, A J

    2001-10-01

    Because current trends in hospital restructuring in North America, amalgamations and mergers, and the aging of health care facilities, the need to restructure physical buildings has become greater. Hospital construction carries with it risks to patients. One key concern is the risk of aspergillosis associated with hospital construction. Infection control practitioners must consider some key factors when addressing land excavation and building demolition, which differ in some ways from construction that occurs within a health care facility. The key factors to consider are project concept, risk assessment of patients, procedures and environment, air quality, routes of entry and egress, soil management, conducting inspections, contingency planning, housekeeping, and lines of cooperation and communication with various stakeholders. Considering these areas will help ensure that health care facility personnel and the workers have exercised diligence in patient care.

  13. Oblique overview, looking eastsoutheast, of fish ladder construction activity after ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Oblique overview, looking east-southeast, of fish ladder construction activity after dewatering of north side. The east abutment wall, concrete crest, and north side apron are exposed. Easternmost roller gate (raised position) and service bridge at upper right - Grand Valley Diversion Dam, Half a mile north of intersection of I-70 & Colorado State Route 65, Cameo, Mesa County, CO

  14. The Reciprocal Organization of Constructive Activity in Drug Addiction

    ERIC Educational Resources Information Center

    Akhmetzyanova, Anna I.; Nikishina, Vera B.; Klyueva, Nadezhda V.; Petrash, Ekaterina A.

    2016-01-01

    The urgency of the problem stated in the article is caused by the fact that modern scientific studies show that sustainable neuro-associative connections with the object of addiction arise at chemical addiction. The aim of this study is to examine the features of the reciprocal organization of constructive activities in drug addiction. Study of…

  15. Current federal activities in school health education.

    PubMed Central

    Gilbert, G G; Davis, R L; Damberg, C L

    1985-01-01

    In 1979, the Federal Government released a report, "Healthy People," that examined the major health problems and the associated preventable risks facing Americans. For the school-age population in particular, several problem areas are notable, such as violence (suicide and homicide), accidents, and drug and alcohol abuse. A number of risk factors related to personal behavior have been identified for these and other health problems facing young Americans. Comprehensive school-based health promotion programs have the potential to influence positively the health status of the school-age population. This article highlights some of the more important recent Federal activities related to school-based health education. PMID:3931164

  16. Current and future offshore activities in Canada

    SciTech Connect

    Hnatiuk, J.

    1987-06-01

    The development of innovative exploratory drilling systems for Canada's harsh Arctic offshore areas over the past decade and future activity in these areas, including possible production concepts, are discussed. The results can be applied in other Arctic areas of the world, including offshore Alaska. This operating experience will advance technology and serve as a basis for the design of Arctic offshore production and transportation systems. Unique technology has been developed and successfully used in the discovery of major accumulations of hyrodcarbons. Continued technological advances are anticipated to have widespread Arctic applications in both exploratory and production operations.

  17. A voltage-activated proton current in human cardiac fibroblasts

    SciTech Connect

    El Chemaly, Antoun; Guinamard, Romain; Demion, Marie; Fares, Nassim; Jebara, Victor; Faivre, Jean-Francois; Bois, Patrick . E-mail: patrick.bois@univ-poitiers.fr

    2006-02-10

    A voltage-activated proton current in human cardiac fibroblasts, measured using the whole-cell recording configuration of the patch-clamp technique, is reported. Increasing the pH of the bathing solution shifted the current activation threshold to more negative potentials and increased both the current amplitude and its rate of activation. Changing the pH gradient by one unit caused a 51 mV shift in the reversal potential of the current, demonstrating a high selectivity for protons of the channel carrying the current. Extracellularly applied Zn{sup 2+} reversibly inhibited the current. Activation of the current contributes to the resting membrane conductance under conditions of intracellular acidosis. It is proposed that this current in cardiac fibroblasts is involved in the regulation of the intracellular pH and the membrane potential under physiological conditions as well as in response to pathological conditions such as ischemia.

  18. Transient sodium current at subthreshold voltages: activation by EPSP waveforms.

    PubMed

    Carter, Brett C; Giessel, Andrew J; Sabatini, Bernardo L; Bean, Bruce P

    2012-09-20

    Tetrodotoxin (TTX)-sensitive sodium channels carry large transient currents during action potentials and also "persistent" sodium current, a noninactivating TTX-sensitive current present at subthreshold voltages. We examined gating of subthreshold sodium current in dissociated cerebellar Purkinje neurons and hippocampal CA1 neurons, studied at 37°C with near-physiological ionic conditions. Unexpectedly, in both cell types small voltage steps at subthreshold voltages activated a substantial component of transient sodium current as well as persistent current. Subthreshold EPSP-like waveforms also activated a large component of transient sodium current, but IPSP-like waveforms engaged primarily persistent sodium current with only a small additional transient component. Activation of transient as well as persistent sodium current at subthreshold voltages produces amplification of EPSPs that is sensitive to the rate of depolarization and can help account for the dependence of spike threshold on depolarization rate, as previously observed in vivo.

  19. Transient sodium current at subthreshold voltages: activation by EPSP waveforms

    PubMed Central

    Carter, Brett C.; Giessel, Andrew J.; Sabatini, Bernardo L.; Bean, Bruce P.

    2012-01-01

    Summary Tetrodotoxin (TTX)-sensitive sodium channels carry large transient currents during action potentials and also “persistent” sodium current, a non-inactivating TTX-sensitive current present at subthreshold voltages. We examined gating of subthreshold sodium current in dissociated cerebellar Purkinje neurons and hippocampal CA1 neurons, studied at 37 °C with near-physiological ionic conditions. Unexpectedly, in both cell types small voltage steps at subthreshold voltages activated a substantial component of transient sodium current as well as persistent current. Subthreshold EPSP-like waveforms also activated a large component of transient sodium current, but IPSP-like waveforms engaged primarily persistent sodium current with only a small additional transient component. Activation of transient as well as persistent sodium current at subthreshold voltages produces amplification of EPSPs that is sensitive to the rate of depolarization and can help account for the dependence of spike threshold on depolarization rate, as previously observed in vivo. PMID:22998875

  20. Utility of pedometers for assessing physical activity: construct validity.

    PubMed

    Tudor-Locke, Catrine; Williams, Joel E; Reis, Jared P; Pluto, Delores

    2004-01-01

    Valid assessment of physical activity is necessary to fully understand this important health-related behaviour for research, surveillance, intervention and evaluation purposes. This article is the second in a companion set exploring the validity of pedometer-assessed physical activity. The previous article published in Sports Medicine dealt with convergent validity (i.e. the extent to which an instrument's output is associated with that of other instruments intended to measure the same exposure of interest). The present focus is on construct validity. Construct validity is the extent to which the measurement corresponds with other measures of theoretically-related parameters. Construct validity is typically evaluated by correlational analysis, that is, the magnitude of concordance between two measures (e.g. pedometer-determined steps/day and a theoretically-related parameter such as age, anthropometric measures and fitness). A systematic literature review produced 29 articles published since > or =1980 directly relevant to construct validity of pedometers in relation to age, anthropometric measures and fitness. Reported correlations were combined and a median r-value was computed. Overall, there was a weak inverse relationship (median r = -0.21) between age and pedometer-determined physical activity. A weak inverse relationship was also apparent with both body mass index and percentage overweight (median r = -0.27 and r = -0.22, respectively). Positive relationships regarding indicators of fitness ranged from weak to moderate depending on the fitness measure utilised: 6-minute walk test (median r = 0.69), timed treadmill test (median r = 0.41) and estimated maximum oxygen uptake (median r = 0.22). Studies are warranted to assess the relationship of pedometer-determined physical activity with other important health-related outcomes including blood pressure and physiological parameters such as blood glucose and lipid profiles. The aggregated evidence of convergent

  1. Multiple sclerosis: impact of physical activity on psychosocial constructs.

    PubMed

    Plow, Matthew A; Mathiowetz, Virgil; Resnik, Linda

    2008-01-01

    To determine the impact of physical activity (PA) interventions and experience with PA on psychosocial constructs. PA, self-efficacy, self-identity, social support, and expected PA frequency were measured pre and post intervention in 39 persons with multiple sclerosis. The MANOVA analysis indicated that self-efficacy and expectation decreased, whereas self-identity and PA improved (P<0.05). Regressions analyses indicated pretest self-identity (beta(2)=0.44) and social support (beta(2)=0.34) were associated with PA. Posttest self-efficacy (beta(2)=0.38) and social support (beta(2)=0.31) were associated with PA (P<0.05). The interventions and experience with PA caused changes in psychosocial constructs, which subsequently affected the correlation of these constructs with PA.

  2. Antimicrobial activity of hydroxytyrosol: a current controversy.

    PubMed

    Medina-Martínez, María S; Truchado, Pilar; Castro-Ibáñez, Irene; Allende, Ana

    2016-01-01

    This study focus on the main factors that affect the antimicrobial capacity of hydroxytyrosol, including the concentration (200, 400, and 1000 μg/mL), target strains, and the culture media (nutrient-rich and less-rich culture media). The potential HT degradation was also evaluated by HPLC-PAD. Kinetic parameters from growth curves showed that HT concentrations produced a doses-dependent shift when compared to the untreated control. In most of the cases, the highest tested dose (1000 μg/mL) was needed to inhibit growth of the selected strains. However, all the strains were able to grow even at the highest HT dose when cultivated in nutrient-rich culture media. It was observed that HT concentrations were reduced by about 15%, except for Escherichia coli 533 and 679 in Muller Hinton broth, where HT was reduced up to 35%. The results showed a limited antimicrobial activity, contrary to information previously published in some research papers.

  3. NASA Lunar Mining and Construction Activities and Plans

    NASA Technical Reports Server (NTRS)

    Sanders, Gerald B.; Larson, William E.; Sacksteder, Kurt R.

    2009-01-01

    the need to implement efforts that are sustainable and affordable. One area NASA is developing that can significantly change how systems required for sustained human presence are designed and integrated, as well as potentially break our reliance on Earth supplied logistics, is In-Situ Resource Utilization (ISRU). ISRU, also known living off the land, involves the extraction and processing of local resources into useful products. In particular, the ability to make propellants, life support consumables, fuel cell reagents, and radiation shielding can significantly reduce the cost, mass, and risk of sustained human activities beyond Earth. Also, the ability to modify the lunar landscape for safer landing, transfer of payloads from the lander an outpost, dust generation mitigation, and infrastructure placement and buildup are also extremely important for long-term lunar operations. While extra-terrestrial excavation, material handling and processing, and site preparation and construction may be new to NASA and other space agencies, there is extensive terrestrial hardware and commercial experience that can be leveraged. This paper will provide an overview of current NASA activities in lunar ISRU mining and construction and how terrestrial experience in these areas are important to achieving the goal of affordable and sustainable human exploration.

  4. Opening remarks: Current and future activities

    NASA Technical Reports Server (NTRS)

    Davarian, Faramaz

    1993-01-01

    It is our custom to present the Propagation Program's recent accomplishments and future plans at the onset of a NAPEX meeting. A summary is presented. The data analysis phase of the U.S. Olympus Campaign is nearing its end. The final report will be published by Virginia Tech by midsummer 1993. The report will comprise measurement analysis for 12 months. It will include monthly and annual attenuation statistics and statistics on scintillation effects. A number of prediction models will be presented. The ACTS propagation experiment preparations are moving forward as expected. The mobile/personal channel characterization efforts continued during the last year. Data collected by the University of Texas in 1992 are being analyzed and will become available by September 1993. We have recently started a study to characterize LEO mobile/personal channels. Topics such as indoor reception, tree shadowing, blockage, and delay spread will be investigated. These results will become available in one to two years from now. We have also collected Ka-band mobile data using Olympus 20 GHz beacon transmissions. The University of Texas has already collected five years of low-elevation angle, 11GHz propagation data. The work on database for propagation models has progressed very well. The first release is ready, and the participants of this meeting will receive a copy of the software. We had an active year where CCIR is concerned. An input document on land mobile satellite system (LMSS) propagation models was submitted to the U.S. national committee and was approved and sent to Geneva.

  5. Design, construction and mechanical optimisation process of electrode with radial current flow in the scala tympani.

    PubMed

    Deman, P R; Kaiser, T M; Dirckx, J J; Offeciers, F E; Peeters, S A

    2003-09-30

    A 48 contact cochlear implant electrode has been constructed for electrical stimulation of the auditory nerve. The stimulating contacts of this electrode are organised in two layers: 31 contacts on the upper surface directed towards the habenula perforata and 17 contacts connected together as one longitudinal contact on the underside. The design of the electrode carrier aims to make radial current flow possible in the cochlea. The mechanical structure of the newly designed electrode was optimised to obtain maximal insertion depth. Electrode insertion tests were performed in a transparent acrylic model of the human cochlea.

  6. Postpartum Physical Activity: Measuring Theory of Planned Behavior Constructs

    PubMed Central

    Hales, Derek; Evenson, Kelly R.; Wen, Fang; Wilcox, Sara

    2012-01-01

    Objective top develop and examine evidence for factor validity and longitudinal invariance of scales used to measure theory of planned behavior constructs applied to physical activity. Methods Self-report questionnaires were administered at 3- (n=267) and 12-months (n=333) postpartum. Longitudinal data were available for 185 of these women. Results A single factor model fit data from the normative beliefs, perceived behavioral control, and behavioral beliefs scales. Attitude and control beliefs were found to be multidimensional. Longitudinal invariance of all scales was supported. Conclusions Each scale had strong validity evidence. Future research using these measures will help identify areas for intervention and reveal how changes in constructs influence physical activity over time. PMID:20218751

  7. Activation of accelerator construction materials by heavy ions

    NASA Astrophysics Data System (ADS)

    Katrík, P.; Mustafin, E.; Hoffmann, D. H. H.; Pavlovič, M.; Strašík, I.

    2015-12-01

    Activation data for an aluminum target irradiated by 200 MeV/u 238U ion beam are presented in the paper. The target was irradiated in the stacked-foil geometry and analyzed using gamma-ray spectroscopy. The purpose of the experiment was to study the role of primary particles, projectile fragments, and target fragments in the activation process using the depth profiling of residual activity. The study brought information on which particles contribute dominantly to the target activation. The experimental data were compared with the Monte Carlo simulations by the FLUKA 2011.2c.0 code. This study is a part of a research program devoted to activation of accelerator construction materials by high-energy (⩾200 MeV/u) heavy ions at GSI Darmstadt. The experimental data are needed to validate the computer codes used for simulation of interaction of swift heavy ions with matter.

  8. Towards the design of 3D multiscale instructive tissue engineering constructs: Current approaches and trends.

    PubMed

    Oliveira, Sara M; Reis, Rui L; Mano, João F

    2015-11-01

    The design of 3D constructs with adequate properties to instruct and guide cells both in vitro and in vivo is one of the major focuses of tissue engineering. Successful tissue regeneration depends on the favorable crosstalk between the supporting structure, the cells and the host tissue so that a balanced matrix production and degradation are achieved. Herein, the major occurring events and players in normal and regenerative tissue are overviewed. These have been inspiring the selection or synthesis of instructive cues to include into the 3D constructs. We further highlight the importance of a multiscale perception of the range of features that can be included on the biomimetic structures. Lastly, we focus on the current and developing tissue-engineering approaches for the preparation of such 3D constructs: top-down, bottom-up and integrative. Bottom-up and integrative approaches present a higher potential for the design of tissue engineering devices with multiscale features and higher biochemical control than top-down strategies, and are the main focus of this review. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Design, construction and performance of the current lead test facility CuLTKa

    NASA Astrophysics Data System (ADS)

    Richter, T.; Bobien, S.; Fietz, W. H.; Heiduk, M.; Heller, R.; Hollik, M.; Lange, C.; Lietzow, R.; Rohr, P.

    2017-09-01

    The Karlsruhe Institute of Technology (KIT) has a longtime experience in the development of High Temperature Superconductor (HTS) Current Leads (CLs) for high currents leading to several contracts with national and international partners. Within these contracts series production and cold acceptance tests of such CLs were required. The cold test of a large number of CLs requires the availability of a flexible facility which allows fast and reproducible testing. With the Current Lead Test Facility Karlsruhe (CuLTKa) a versatile and flexible test bed for CLs was designed and constructed. The facility consists of five cryostats including two test boxes and is directly connected by a transfer line to a refrigerator with a capacity of 2 kW at 4.4 K. The refrigerator supplies supercritical helium at two different temperature levels simultaneously. Each of the two test cryostats can be equipped with a pair of CLs which is short-circuited at the low temperature level via a superconducting bus bar. For current tests a power supply can provide DC currents up to 30 kA. If required, the facility design offers the potential of withstanding high voltages of up to 50 kV on the test objects. The commissioning of the facility started in July 2014. In total a series of acceptance tests of the CLs for the Japanese JT-60SA will be carried out until second half of 2017 to qualify six CLs with a current of 26 kA and 20 CLs with a current of 20 kA. In the meantime, six CLs@26 kA and 16 CLs@20 kA have been tested in CuLTKa which demonstrates the very effective operation of the facility. This paper describes the setup of the facility from cryogenic, electrical and process control point of view and will highlight the design of particular technical aspects. Furthermore, an overview of the performance during the commissioning phase will be given.

  10. DISTRIBUTION OF ELECTRIC CURRENTS IN SOLAR ACTIVE REGIONS

    SciTech Connect

    Török, T.; Titov, V. S.; Mikić, Z.; Leake, J. E.; Archontis, V.; Linton, M. G.; Dalmasse, K.; Aulanier, G.; Kliem, B.

    2014-02-10

    There has been a long-standing debate on the question of whether or not electric currents in solar active regions are neutralized. That is, whether or not the main (or direct) coronal currents connecting the active region polarities are surrounded by shielding (or return) currents of equal total value and opposite direction. Both theory and observations are not yet fully conclusive regarding this question, and numerical simulations have, surprisingly, barely been used to address it. Here we quantify the evolution of electric currents during the formation of a bipolar active region by considering a three-dimensional magnetohydrodynamic simulation of the emergence of a sub-photospheric, current-neutralized magnetic flux rope into the solar atmosphere. We find that a strong deviation from current neutralization develops simultaneously with the onset of significant flux emergence into the corona, accompanied by the development of substantial magnetic shear along the active region's polarity inversion line. After the region has formed and flux emergence has ceased, the strong magnetic fields in the region's center are connected solely by direct currents, and the total direct current is several times larger than the total return current. These results suggest that active regions, the main sources of coronal mass ejections and flares, are born with substantial net currents, in agreement with recent observations. Furthermore, they support eruption models that employ pre-eruption magnetic fields containing such currents.

  11. Mesh optimization for microbial fuel cell cathodes constructed around stainless steel mesh current collectors

    NASA Astrophysics Data System (ADS)

    Zhang, Fang; Merrill, Matthew D.; Tokash, Justin C.; Saito, Tomonori; Cheng, Shaoan; Hickner, Michael A.; Logan, Bruce E.

    Mesh current collectors made of stainless steel (SS) can be integrated into microbial fuel cell (MFC) cathodes constructed of a reactive carbon black and Pt catalyst mixture and a poly(dimethylsiloxane) (PDMS) diffusion layer. It is shown here that the mesh properties of these cathodes can significantly affect performance. Cathodes made from the coarsest mesh (30-mesh) achieved the highest maximum power of 1616 ± 25 mW m -2 (normalized to cathode projected surface area; 47.1 ± 0.7 W m -3 based on liquid volume), while the finest mesh (120-mesh) had the lowest power density (599 ± 57 mW m -2). Electrochemical impedance spectroscopy showed that charge transfer and diffusion resistances decreased with increasing mesh opening size. In MFC tests, the cathode performance was primarily limited by reaction kinetics, and not mass transfer. Oxygen permeability increased with mesh opening size, accounting for the decreased diffusion resistance. At higher current densities, diffusion became a limiting factor, especially for fine mesh with low oxygen transfer coefficients. These results demonstrate the critical nature of the mesh size used for constructing MFC cathodes.

  12. Construction monitoring activities in the ESF starter tunnel

    SciTech Connect

    Pott, J.; Carlisle, S.

    1994-05-01

    In situ design verification activities am being conducted in the North Ramp Starter Tunnel of the Yucca Mountain Project Exploratory Studies Facility. These activities include: monitoring the peak particle velocities and evaluating the damage to the rock mass associated with construction blasting, assessing the rock mass quality surrounding the tunnel, monitoring the performance of the installed ground support, and monitoring the stability of the tunnel. In this paper, examples of the data that have been collected and preliminary conclusions from the data are presented.

  13. Mechanical Activation of Construction Binder Materials by Various Mills

    NASA Astrophysics Data System (ADS)

    Fediuk, R. S.

    2016-04-01

    The paper deals with the mechanical grinding down to the nano powder of construction materials. During mechanical activation a composite binder active molecules cement minerals occur in the destruction of the molecular defects in the areas of packaging and breaking metastable phase decompensation intermolecular forces. The process is accompanied by a change in the kinetics of hardening of portland cement. Mechanical processes during grinding mineral materials cause, along with the increase in their surface energy, increase the Gibbs energy of powders and, respectively, their chemical activity, which also contributes to the high adhesion strength when contacting them with binders. Thus, the set of measures for mechanical activation makes better use of the weight of components filled with cement systems and adjust their properties. At relatively low cost is possible to provide a spectacular and, importantly, easily repeatable results in a production environment.

  14. Hypotonicity activates a native chloride current in Xenopus oocytes

    PubMed Central

    1994-01-01

    Xenopus oocytes are frequently utilized for in vivo expression of cellular proteins, especially ion channel proteins. A thorough understanding of the endogenous conductances and their regulation is paramount for proper characterization of expressed channel proteins. Here we detail a novel chloride current (ICl.swell) responsive to hypotonicity in Xenopus oocytes using the two-electrode voltage clamp technique. Reducing the extracellular osmolarity by 50% elicited a calcium-independent chloride current having an anion conductivity sequence identical with swelling-induced chloride currents observed in epithelial cells. The hypotonicity-activated current was blocked by chloride channel blockers, trivalent lanthanides, and nucleotides. G- protein, cAMP-PKA, and arachidonic acid signaling cascades were not involved in ICl.swell activation. ICl.swell is distinct from both stretch-activated nonselective cation channels and the calcium- activated chloride current in oocytes and may play a critical role in volume regulation in Xenopus oocytes. PMID:8189203

  15. Explorations of electric current system in solar active regions. I - Empirical inferences of the current flows

    NASA Technical Reports Server (NTRS)

    Ding, Y. J.; Hong, Q. F.; Hagyard, M. J.; Deloach, A. C.; Liu, X. P.

    1987-01-01

    Techniques to identify sources of electric current systems and their channels of flow in solar active regions are explored. Measured photospheric vector magnetic fields together with high-resolution white-light and H-alpha filtergrams provide the data base to derive the current systems in the photosphere and chromosphere. As an example, the techniques are then applied to infer current systems in AR 2372 in early April 1980.

  16. Constructing bioactive peptides with pH-dependent activities.

    PubMed

    Tu, Zhigang; Volk, Melanie; Shah, Khushali; Clerkin, Kevin; Liang, Jun F

    2009-08-01

    Many bioactive peptides are featured by their arginine and lysine rich contents. In this study, lysine and arginine residues in lytic peptides were selectively replaced by histidines. Although resulting histidine-containing lytic peptides had decreased activity, they did show pH-dependent cytotoxicity. The activity of the constructed histidine-containing lytic peptides increased 2-8 times as the solution pH changed from 7.4 to 5.5. More importantly, these histidine-containing peptides maintain the same cell killing mechanism as their parent peptides by causing cell lysis. Both the activity and pH-sensitivity of histidine-containing peptides are tunable by adjusting histidine substitution numbers and positions. This study has presented a general strategy to create bioactive peptides with desired pH-sensitivity to meet the needs of various applications such as cancer treatments.

  17. Constructing bioactive peptides with pH-dependent activities

    PubMed Central

    Tu, Zhigang; Volk, Melanie; Shah, Khushali; Clerkin, Kevin; Liang, Jun F.

    2009-01-01

    Many bioactive peptides are featured by their arginine and lysine rich contents. In this study, lysine and arginine residues in lytic peptides were selectively replaced by histidines. Although resulted histidine-containing lytic peptides had decreased activity, they did show pH-dependent cytotoxicity. The activity of the constructed histidine-containing lytic peptides increased 2 ~ 8 times as the solution pH changed from of 7.4 to 5.5. More importantly, these histidine-containing peptides maintain the same cell killing mechanism as their parent peptides by causing cell lysis. Both the activity and pH-sensitivity of histidine-containing peptides are tunable by adjusting histidine substitution numbers and positions. This study has presented a general strategy to create bioactive peptides with desired pH-sensitivity to meet the needs of various applications such as cancer treatments. PMID:19464332

  18. Active-constructive-interactive: a conceptual framework for differentiating learning activities.

    PubMed

    Chi, Michelene T H

    2009-01-01

    Active, constructive, and interactive are terms that are commonly used in the cognitive and learning sciences. They describe activities that can be undertaken by learners. However, the literature is actually not explicit about how these terms can be defined; whether they are distinct; and whether they refer to overt manifestations, learning processes, or learning outcomes. Thus, a framework is provided here that offers a way to differentiate active, constructive, and interactive in terms of observable overt activities and underlying learning processes. The framework generates a testable hypothesis for learning: that interactive activities are most likely to be better than constructive activities, which in turn might be better than active activities, which are better than being passive. Studies from the literature are cited to provide evidence in support of this hypothesis. Moreover, postulating underlying learning processes allows us to interpret evidence in the literature more accurately. Specifying distinct overt activities for active, constructive, and interactive also offers suggestions for how learning activities can be coded and how each kind of activity might be elicited.

  19. Beyond Peptides and mAbs - Current Status and Future Perspectives for Biotherapeutics with Novel Constructs

    PubMed Central

    AlDeghaither, Dalal; Smaglo, Brandon G; Weiner, Louis M.

    2014-01-01

    Biotherapeutics are attractive anti-cancer agents due to their high specificity and limited toxicity compared to conventional small molecules. Antibodies are widely used in cancer therapy, either directly or conjugated to a cytotoxic payload. Peptide therapies, though not as prevalent, have been utilized in hormonal therapy and imaging. The limitations associated with unmodified forms of both types of biotherapeutics have led to the design and development of novel structures, which incorporate key features and structures that have improved the molecules’ abilities to bind to tumor targets, avoid degradation and exhibit favorable pharmacokinetics. In this review we highlight the current status of monoclonal antibodies and peptides, and provide a perspective on the future of biotherapeutics using novel constructs. PMID:25707963

  20. Selective regulation of current densities underlies spontaneous changes in the activity of cultured neurons.

    PubMed

    Turrigiano, G; LeMasson, G; Marder, E

    1995-05-01

    We study the electrical activity patterns and the expression of conductances in adult stomatogastric ganglion (STG) neurons as a function of time in primary cell culture. When first plated in culture, these neurons had few active properties. After 1 d in culture they produced small action potentials that rapidly inactivated during maintained depolarization. After 2 d in culture they fired large action potentials tonically when depolarized, and their properties resembled very closely the properties of STG neurons pharmacologically isolated in the ganglion. After 3-4 d in culture, however, their electrical properties changed and they fired in bursts when depolarized. We characterized the currents expressed by these neurons in culture. They included two TTX-sensitive sodium currents, a calcium current, a delayed-rectifier-like current, a calcium-dependent potassium current, and two A-type currents. The changes in firing properties with time in culture were accompanied by an increase in inward and decrease in outward current densities. A single-compartment conductance-based model of an STG neuron was constructed by fitting the currents measured in the biological neurons. When the current densities in the model neuron were matched to those measured for the biological neurons in each activity state, the model neuron closely reproduced each state, indicating that the changes in current densities are sufficient to account for the changes in intrinsic properties. These data indicate that STG neurons isolated in culture change their intrinsic electrical properties by selectively adjusting the magnitudes of their ionic conductances.

  1. Voltage-activated proton current in eosinophils from human blood.

    PubMed Central

    Gordienko, D V; Tare, M; Parveen, S; Fenech, C J; Robinson, C; Bolton, T B

    1996-01-01

    1. The resting membrane potential of freshly purified normodense human eosinophils bathed in and dialysed with quasi-physiological solutions was -63 +/- 2 mV (n = 100). 2. In voltage-clamp mode with quasi-physiological internal and external solutions, voltage steps from the holding potential of -60 mV to levels positive to +20 mV resulted in development of a quasi-instantaneous outward current and a slowly developing outward current. The instantaneous current was absent when the cells were bathed in and dialysed with K(+)-free solution. 3. The slow outward current persisted following simultaneous replacement of K+, Na+ and most of the Cl- with largely impermeant ions (tetraethylammonium, N-methyl-D-glucamine and methanesulphonate) and was augmented when the cell was dialysed with a solution of increased buffering capacity for protons. The observed reversal potential of the current closely followed the hydrogen equilibrium potential over a wide range of internal-external pH combinations, indicating that the conductance underlying the slow outward current was highly selective for H+ ions. 4. Acidification of the pipette solution (increasing [H+]i) augmented the outward H+ current and shifted its activation range negatively, whilst acidification of the external solution had the opposite effect. The voltage dependence of the current is modulated by the transmembrane pH gradient so the only outward current could be activated. However, when the outward current was activated by a voltage step, rapid acidification of external solution produced an inward H+ current which rapidly deactivated. 5. The proton current was reversibly inhibited in a voltage-dependent manner by extracellular application of Zn2+. The apparent dissociation constants were 8 nM (at +40 mV), 36 nM (at +70 mV) and 200 nM (at +100 mV). 6. The proton current was augmented by exposure to 10 microM arachidonic acid. This augmentation consisted of a shift of the voltage dependence of activation to more

  2. [Bactericidal Activity of Constructed Recombinant Fusion Protein Pheromonicin-CT].

    PubMed

    Yu, Huan; Zuo, Yue-wen; Qiu, Xiao-qing

    2015-11-01

    To construct engineering peptide pheromonicin-Clostrzaum tretant krn-ui), and to test its bactericidal activity. We amplified the gene of variable regions from hybridoma cells which secreted monoclonal antibody (mAb) against antigen in the membrane of Clostridium tetani and linked the small antibody mimetic to the channel-forming domain of colicin Ia to create Ph-CT. The Ph-CT was purified by CM sepharose ion-exchange column. Its in vitro antibacterial activity was evaluated by colony culture with different doses of Ph-CT (final concentration 2, 4, 8, and 16 microg/mL,respectively). Then we inoculated culture medium with CT strains and different doses of Ph-CT (final concentration of 4 and 16 microg/mL). The in vivo antibacterial activity of Ph-CT was evaluated by cumulative survival of mice. After 16 hours' anaerobic culture, the mice was treated with filtered CT medium or CT medium. We constructed Ph-CT successfully. CT colonies appeared in the CT medium treated with Ph-CT (2, 4 microg/mL), while no colony appeared in the CT medium treated with Ph-CT (8, 16 microg/mL). All mice survived when they were injected with filtered CT medium treated with Ph-CT (4, 16 microg/mL) and CT medium treated with Ph-CT (16 microg/mL). Three (50%) mice survived when they were injected with CT medium treated with Ph-CT (4 microg/mL). All mice in the control groups died after CT infections. Ph-CT may be of value as antibiotics against Clostridium tetani.

  3. Suppression of spontaneous epileptiform activity with applied currents.

    PubMed

    Nakagawa, M; Durand, D

    1991-12-20

    It has been well established that both applied and endogenous electric fields can modulate neuronal activity in various preparations. In this paper, we present the effects of applied currents on spontaneous epileptiform activity in the CA1 region of the rat hippocampus. A computer-controlled system was designed to detect the spontaneous abnormal activity and then apply current pulses of programmable amplitude with monopolar electrodes in the stratum pyramidale. The epileptiform activity was generated by subperfusion of the neural tissue with an elevated potassium artificial cerebrospinal fluid (CSF) solution. Extracellular recordings showed that the interictal bursts could be fully suppressed in 90% of the slices by subthreshold currents with an average amplitude of 12.5 microA. Intracellular recordings showed that the anodic currents generated hyperpolarization of the somatic membrane thereby suppressing neuronal firing. This inhibitory effect of applied current pulses is important for the understanding of electric field effects on abnormal neuronal activity and could be an effective means of preventing the spread of epileptiform activity.

  4. Factors influencing dust exposure: finishing activities in drywall construction.

    PubMed

    Simmons, Catherine E; Jones, Rachael M; Boelter, Fred W

    2011-05-01

    Sanding drywall joint compound is a dusty construction activity. We studied potential factors influencing exposure to respirable and total dust for sanders and bystanders in the area of drywall joint compound finishing in 17 test events within a room-scale isolation chamber. We found the air change rate to be negatively correlated with dust C(twa) both in the sander's personal breathing zone and surrounding area. We could not conclude that sanding tool type systematically influences dust C(twa), but the use of 80-grit abrasive was associated with the highest dust C(twa). We found respirable dusts were uniformly dispersed 1-8.2 m from sanding activities at a fixed location. As anticipated, both respirable and total dust C(twa) in the sander's personal breathing zone are higher than in the surrounding area. The respirable fraction of the total dust mass C(twa) was greater in the surrounding area than in the sander's personal breathing zone. Respirable dust concentrations measured in real time increased over the duration of sanding, exhibiting a temporal trend that is similar to that predicted by the well-mixed box model with contaminant removal by mechanical ventilation only, and continuous emission. Dust concentrations returned to pre-activity (background) levels 2-4 hr after cessation of the sanding activity.

  5. Bioglass Activated Skin Tissue Engineering Constructs for Wound Healing.

    PubMed

    Yu, Hongfei; Peng, Jinliang; Xu, Yuhong; Chang, Jiang; Li, Haiyan

    2016-01-13

    Wound healing is a complicated process, and fibroblast is a major cell type that participates in the process. Recent studies have shown that bioglass (BG) can stimulate fibroblasts to secrete a multitude of growth factors that are critical for wound healing. Therefore, we hypothesize that BG can stimulate fibroblasts to have a higher bioactivity by secreting more bioactive growth factors and proteins as compared to untreated fibroblasts, and we aim to construct a bioactive skin tissue engineering graft for wound healing by using BG activated fibroblast sheet. Thus, the effects of BG on fibroblast behaviors were studied, and the bioactive skin tissue engineering grafts containing BG activated fibroblasts were applied to repair the full skin lesions on nude mouse. Results showed that BG stimulated fibroblasts to express some critical growth factors and important proteins including vascular endothelial growth factor, basic fibroblast growth factor, epidermal growth factor, collagen I, and fibronectin. In vivo results revealed that fibroblasts in the bioactive skin tissue engineering grafts migrated into wound bed, and the migration ability of fibroblasts was stimulated by BG. In addition, the bioactive BG activated fibroblast skin tissue engineering grafts could largely increase the blood vessel formation, enhance the production of collagen I, and stimulate the differentiation of fibroblasts into myofibroblasts in the wound site, which would finally accelerate wound healing. This study demonstrates that the BG activated skin tissue engineering grafts contain more critical growth factors and extracellular matrix proteins that are beneficial for wound healing as compared to untreated fibroblast cell sheets.

  6. Current developments at Giprokoks for coke-battery construction and reconstruction

    SciTech Connect

    V.I. Rudyka; Y.E. Zingerman; V.B. Kamenyuka; O.N. Surenskii; G.E. Kos'kova; V.V. Derevich; V.A. Gushchin

    2009-07-15

    Approaches developed at Giprokoks for coke-battery construction and reconstruction are considered. Recommendations regarding furnace construction and reconstruction are made on the basis of Ukrainian and world experience.

  7. Calcium current and calcium-activated inward current in the oocyte of the starfish Leptasterias hexactis.

    PubMed Central

    Lansman, J B

    1987-01-01

    1. Inward currents in the immature oocyte of the starfish Leptasterias hexactis were studied with a two-micro-electrode voltage clamp. Experiments investigated the role of Ca2+ in the Na+-dependent plateau of the action potential. 2. Voltage steps more positive than -55 mV produced inward currents in normal sea water that activated and then decayed to a non-zero level with a double-exponential time course. Returning the voltage to the resting potential produced an inward tail current that relaxed slowly to zero with a time course of seconds. 3. Replacing Na+ with choline abolished the slowly decaying component as well as the slow tail current which followed the end of the voltage pulse. This suggested that inward current in Na+-containing sea water consisted of a rapidly decaying component that flowed through Ca2+ channels and a more slowly decaying component carried by Na+. 4. Ca2+ current was isolated in Na+-free sea water. Activation followed a sigmoidal time course that could be described with m2 kinetics. Inactivation during a maintained depolarization followed first-order kinetics and was voltage dependent. 5. When Ba2+ was substituted for Ca2+ as the divalent ion charge carrier, inward currents in Na+-containing sea water decayed along a single-exponential time course. The absence of a slowly decaying Na+ current in Ba2+-containing sea water suggested that Na+ current depended on Ca2+ influx. 6. The effects of altering Ca2+ influx on the time course of Na+ current were investigated. Na+ current decayed more rapidly as the test pulse potential was made more positive, while raising [Ca2+]o slowed the decaying phase without altering its dependence on membrane potential. 7. Tail currents measured after rapidly stepping the membrane potential back to the resting level consisted of a fast component associated with the closing of Ca2+ channels and a slow component that was abolished by removing Na+. 8. The variation of the amplitude of the slow component of tail

  8. Bacterial activity in plant (Schoenoplectus validus) biofilms of constructed wetlands.

    PubMed

    Pollard, Peter C

    2010-12-01

    Biofilm-bacterial communities have been exploited in the treatment of wastewater in 'fixed-film' processes. Our understanding of biofilm dynamics requires a quantitative knowledge of bacterial growth-kinetics in these microenvironments. The aim of this paper was to apply the thymidine assay to quantify bacterial growth without disturbing the biofilm on the surfaces of emergent macrophytes (Schoenoplectus validus) of a constructed wetland. The isotope was rapidly and efficiently taken-up and incorporated into dividing biofilm-bacteria. Isotope diffusion into the biofilm did not limit the growth rate measurement. Isotope dilution was inhibited at >12 μM thymidine. Biofilm-bacterial biomass and growth rates were not correlated to the plant surface area (r(2) < 0.02). The measurements of in situ biofilm-bacterial growth rates both displayed, and accommodated, the inherent heterogeneity of the complex wetland ecosystem. Biofilm-bacterial respiratory activities, measured using the redox dye CTC, and growth rates were measured simultaneously. The dye did not interfere with bacterial growth. Biofilm-bacterial specific growth rates ranged from 1.4 ± 0.6 d(-1) to 3.3 ± 1.3 d(-1). In the constructed wetlands of this study biofilm-bacterial specific growth rates, compared to those of natural ecosystems, could be markedly improved through changes in wetland design that increased bacterial respiration while minimising biofilm growth.

  9. THE ORIGIN OF NET ELECTRIC CURRENTS IN SOLAR ACTIVE REGIONS

    SciTech Connect

    Dalmasse, K.; Kliem, B.; Török, T.

    2015-09-01

    There is a recurring question in solar physics regarding whether or not electric currents are neutralized in active regions (ARs). This question was recently revisited using three-dimensional (3D) magnetohydrodynamic (MHD) numerical simulations of magnetic flux emergence into the solar atmosphere. Such simulations showed that flux emergence can generate a substantial net current in ARs. Other sources of AR currents are photospheric horizontal flows. Our aim is to determine the conditions for the occurrence of net versus neutralized currents with this second mechanism. Using 3D MHD simulations, we systematically impose line-tied, quasi-static, photospheric twisting and shearing motions to a bipolar potential magnetic field. We find that such flows: (1) produce both direct and return currents, (2) induce very weak compression currents—not observed in 2.5D—in the ambient field present in the close vicinity of the current-carrying field, and (3) can generate force-free magnetic fields with a net current. We demonstrate that neutralized currents are in general produced only in the absence of magnetic shear at the photospheric polarity inversion line—a special condition that is rarely observed. We conclude that  photospheric flows, as magnetic flux emergence, can build up net currents in the solar atmosphere, in agreement with recent observations. These results thus provide support for eruption models based on pre-eruption magnetic fields that possess a net coronal current.

  10. Pacemaker activity and ionic currents in mouse atrioventricular node cells.

    PubMed

    Marger, Laurine; Mesirca, Pietro; Alig, Jacqueline; Torrente, Angelo; Dubel, Stefan; Engeland, Birgit; Kanani, Sandra; Fontanaud, Pierre; Striessnig, Jörg; Shin, Hee-Sup; Isbrandt, Dirk; Ehmke, Heimo; Nargeot, Joël; Mangoni, Matteo E

    2011-01-01

    It is well established that Pacemaker activity of the sino-atrial node (SAN) initiates the heartbeat. However, the atrioventricular node (AVN) can generate viable pacemaker activity in case of SAN failure, but we have limited knowledge of the ionic bases of AVN automaticity. We characterized pacemaker activity and ionic currents in automatic myocytes of the mouse AVN. Pacemaking of AVN cells (AVNCs) was lower than that of SAN pacemaker cells (SANCs), both in control conditions and upon perfusion of isoproterenol (ISO). Block of I(Na) by tetrodotoxin (TTX) or of I(Ca,L) by isradipine abolished AVNCs pacemaker activity. TTX-resistant (I(Nar)) and TTX-sensitive (I(Nas)) Na(+) currents were recorded in mouse AVNCs, as well as T-(I(Ca,T)) and L-type (I(Ca,L)) Ca(2+) currents I(Ca,L) density was lower than in SANCs (51%). The density of the hyperpolarization-activated current, (I(f)) and that of the fast component of the delayed rectifier current (I(Kr)) were, respectively, lower (52%) and higher (53%) in AVNCs than in SANCs. Pharmacological inhibition of I(f) by 3 µM ZD-7228 reduced pacemaker activity by 16%, suggesting a relevant role for I(f) in AVNCs automaticity. Some AVNCs expressed also moderate densities of the transient outward K(+) current (I(to)). In contrast, no detectable slow component of the delayed rectifier current (I(Ks)) could be recorded in AVNCs. The lower densities of I(f) and I(Ca,L), as well as higher expression of I(Kr) in AVNCs than in SANCs may contribute to the intrinsically slower AVNCs pacemaking than that of SANCs.

  11. CURRENT AND KINETIC HELICITY OF LONG-LIVED ACTIVITY COMPLEXES

    SciTech Connect

    Komm, Rudolf; Gosain, Sanjay

    2015-01-01

    We study long-lived activity complexes and their current helicity at the solar surface and their kinetic helicity below the surface. The current helicity has been determined from synoptic vector magnetograms from the NSO/SOLIS facility, and the kinetic helicity of subsurface flows has been determined with ring-diagram analysis applied to full-disk Dopplergrams from NSO/GONG and SDO/HMI. Current and kinetic helicity of activity complexes follow the hemispheric helicity rule with mainly positive values (78%; 78%, respectively, with a 95% confidence level of 31%) in the southern hemisphere and negative ones (80%; 93%, respectively, with a 95% confidence level of 22% and 14%, respectively) in the northern hemisphere. The locations with the dominant sign of kinetic helicity derived from Global Oscillation Network Group (GONG) and SDO/HMI data are more organized than those of the secondary sign even if they are not part of an activity complex, while locations with the secondary sign are more fragmented. This is the case for both hemispheres even for the northern one where it is not as obvious visually due to the large amount of magnetic activity present as compared to the southern hemisphere. The current helicity shows a similar behavior. The dominant sign of current helicity is the same as that of kinetic helicity for the majority of the activity complexes (83% with a 95% confidence level of 15%). During the 24 Carrington rotations analyzed here, there is at least one longitude in each hemisphere where activity complexes occur repeatedly throughout the epoch. These ''active'' longitudes are identifiable as locations of strong current and kinetic helicity of the same sign.

  12. Electric currents and coronal heating in NOAA active region 6952

    NASA Technical Reports Server (NTRS)

    Metcalf, T. R.; Canfield, R. C.; Hudson, H. S.; Mickey, D. L.; Wulser, J. -P.; Martens, P. C. H.; Tsuneta, S.

    1994-01-01

    We examine the spatial and temporal relationship between coronal structures observed with the soft X-ray telescope (SXT) on board the Yohkoh spacecraft and the vertical electric current density derived from photospheric vector magnetograms obtained using the Stokes Polarimeter at the Mees Solar Observatory. We focus on a single active region: AR 6952 which we observed on 7 days during 1991 December. For 11 independent maps of the vertical electric current density co-aligned with non-flaring X-ray images, we search for a morphological relationship between sites of high vertical current density in the photosphere and enhanced X-ray emission in the overlying corona. We find no compelling spatial or temporal correlation between the sites of vertical current and the bright X-ray structures in this active region.

  13. Voltage and Current Unbalance Compensation Using a Parallel Active Filter

    SciTech Connect

    Xu, Yan; Tolbert, Leon M; Kueck, John D; Rizy, D Tom

    2007-01-01

    A three-phase insulated gate bipolar transistor (IGBT)-based parallel active filter is used for current and/or voltage unbalance compensation. An instantaneous power theory is adopted for real-time calculation and control. Three control schemes, current control, voltage control, and integrated control are proposed to compensate the unbalance of current, voltage, or both. The compensation results of the different control schemes in unbalance cases (load unbalance or voltage source unbalance) are compared and analyzed. The simulation and experimental results show that the control schemes can compensate the unbalance in load current or in the voltage source. Different compensation objectives can be achieved, i.e., balanced and unity power factor source current, balanced and regulated voltage, or both, by choosing appropriate control schemes.

  14. Proton block of proton-activated TRPV1 current

    PubMed Central

    Lee, Bo Hyun

    2015-01-01

    The TRPV1 cation channel is a polymodal nociceptor that is activated by heat and ligands such as capsaicin and is highly sensitive to changes in extracellular pH. In the body core, where temperature is usually stable and capsaicin is normally absent, H+ released in response to ischemia, tissue injury, or inflammation is the best-known endogenous TRPV1 agonist, activating the channel to mediate pain and vasodilation. Paradoxically, removal of H+ elicits a transient increase in TRPV1 current that is much larger than the initial H+-activated current. We found that this prominent OFF response is caused by rapid recovery from H+ inhibition of the excitatory current carried by H+-activated TRPV1 channels. H+ inhibited current by interfering with ion permeation. The degree of inhibition is voltage and permeant ion dependent, and it can be affected but not eliminated by mutations to acidic residues within or near the ion selectivity filter. The opposing H+-mediated gating and permeation effects produce complex current responses under different cellular conditions that are expected to greatly affect the response of nociceptive neurons and other TRPV1-expressing cells. PMID:26170176

  15. Pressure garments for use in the treatment of hypertrophic scars -- an evaluation of current construction techniques in NHS hospitals.

    PubMed

    Macintyre, Lisa; Baird, Margot

    2005-02-01

    The purpose of this investigation was to establish the variety of pressure garment construction methods and materials used in UK hospitals. This paper reports an investigation conducted in two parts. First, a survey of pressure garment practitioners was conducted and second, 15 of the fabrics currently used in UK hospitals were tested. The results showed that the pressures exerted by pressure garments constructed in UK hospitals were likely to range from ineffectively low to dangerously high.

  16. Construction

    DTIC Science & Technology

    2002-01-01

    Harbor Deepening Project, Jacksonville, FL Palm Valley Bridge Project, Jacksonville, FL Rotary Club of San Juan, San Juan, PR Tren Urbano Subway...David. What is nanotechnology? What are its implications for construction?, Foresight/CRISP Workshop on Nanotechnology, Royal Society of Arts

  17. Construction

    DTIC Science & Technology

    2002-01-01

    San Juan, PR Tren Urbano Subway Project, San Juan, PR U.S. Army South, San Juan, PR U.S. Coast Guard Housing Project, San Juan, PR U.S. Coast Guard...construction?, Foresight/CRISP Workshop on Nanotechnology, Royal Society of Arts . Cheltenham, England: 2001, p.5. 56 Concrete Proposals, Economist, July 24

  18. Antiepileptic Activity of Preferential Inhibitors of Persistent Sodium Current

    PubMed Central

    Anderson, Lyndsey L.; Thompson, Christopher H.; Hawkins, Nicole A.; Nath, Ravi D.; Petersohn, Adam A.; Rajamani, Sridharan; Bush, William S.; Frankel, Wayne N.; Vanoye, Carlos G.; Kearney, Jennifer A.; George, Alfred L.

    2014-01-01

    Objective Evidence from basic neurophysiology and molecular genetics has implicated persistent sodium current conducted by voltage-gated sodium (NaV) channels as a contributor to the pathogenesis of epilepsy. Many antiepileptic drugs target NaV channels and modulate neuronal excitability mainly by a use-dependent block of transient sodium current, although suppression of persistent current may also contribute to the efficacy of these drugs. We hypothesized that a drug or compound capable of preferential inhibition of persistent sodium current would have antiepileptic activity. Methods We examined the antiepileptic activity of two selective persistent sodium current blockers ranolazine, an FDA-approved drug for treatment of angina pectoris, and GS967, a novel compound with more potent effects on persistent current, in the epileptic Scn2aQ54 mouse model. We also examined the effect of GS967 in the maximal electroshock model and evaluated effects of the compound on neuronal excitability, propensity for hilar neuron loss, development of mossy fiber sprouting and survival of Scn2aQ54 mice. Results We found that ranolazine was capable of reducing seizure frequency by ~50% in Scn2aQ54 mice. The more potent persistent current blocker GS967 reduced seizure frequency by greater than 90% in Scn2aQ54 mice and protected against induced seizures in the maximal electroshock model. GS967 greatly attenuated abnormal spontaneous action potential firing in pyramidal neurons acutely isolated from Scn2aQ54 mice. In addition to seizure suppression in vivo, GS967 treatment greatly improved the survival of Scn2aQ54 mice, prevented hilar neuron loss, and suppressed the development of hippocampal mossy fiber sprouting. Significance Our findings indicate that the selective persistent sodium current blocker GS967 has potent antiepileptic activity and this compound could inform development of new agents. PMID:24862204

  19. Current Activity of the U.S. ASTER Science Team

    NASA Technical Reports Server (NTRS)

    Kahle, A. B.; Abrams, M. J.; Hook, S. J.; Pieri, D. C.; Ramsey, M.; Rowan, L. C.; Schmugge, T.; Wessels, R.

    2001-01-01

    The U.S. ASTER Science Team is currently engaged in numerous ASTER related activities, many of them jointly with our Japanese colleagues. These include vicarious instrument calibration, algorithm development and validation for higher level data products, assistance to ERSDAC for scheduling activities (primarily for U.S. users), assistance to data users other than Science Team members, and science applications of ASTER data, notably in the areas of glacial monitoring, volcanic monitoring, heat balance determinations, geologic mapping, and cloud studies.

  20. IS THE CURRENT LACK OF SOLAR ACTIVITY ONLY SKIN DEEP?

    SciTech Connect

    Broomhall, A.-M.; Chaplin, W. J.; Elsworth, Y.; Fletcher, S. T.; New, R. E-mail: wjc@bison.ph.bham.ac.uk E-mail: S.Fletcher@shu.ac.uk

    2009-08-01

    The Sun is a variable star whose magnetic activity and total irradiance vary on a timescale of approximately 11 years. The current activity minimum has attracted considerable interest because of its unusual duration and depth. This raises the question: what might be happening beneath the surface where the magnetic activity ultimately originates? The surface activity can be linked to the conditions in the solar interior by the observation and analysis of the frequencies of the Sun's natural seismic modes of oscillation-the p modes. These seismic frequencies respond to changes in activity and are probes of conditions within the Sun. The Birmingham Solar-Oscillations Network (BiSON) has made measurements of p-mode frequencies over the last three solar activity cycles, and so is in a unique position to explore the current unusual and extended solar minimum. We show that the BiSON data reveal significant variations of the p-mode frequencies during the current minimum. This is in marked contrast to the surface activity observations, which show little variation over the same period. The level of the minimum is significantly deeper in the p-mode frequencies than in the surface observations. We observe a quasi-biennial signal in the p-mode frequencies, which has not previously been observed at mid- and low-activity levels. The stark differences in the behavior of the frequencies and the surface activity measures point to activity-related processes occurring in the solar interior, which are yet to reach the surface, where they may be attenuated.

  1. Modulation of divalent cation-activated chloride ion currents.

    PubMed

    Scott, R H; McGuirk, S M; Dolphin, A C

    1988-07-01

    1. Voltage-sensitive calcium channel currents carried by Ca2+ (ICa) or Ba2+ (IBa) were followed by tail currents carried by Cl- ions in approximately 45% of cultured dorsal root ganglion neurones. 2. Extracellular application of (-)-baclofen (100 microM) inhibited IBa and ICl(Ba). Bay K 8644 (5 microM) potentiated both currents. 3. Intracellular GTP-gamma-S increased the proportion of neurones in which ICl(Ba) was recorded. In addition, the activation by GTP-gamma-S of a pertussis toxin-sensitive GTP binding (G)-protein resulted in a steady increase in the Cl- tail current with time, despite a concurrent reduction in IBa. 4. Extracellular application of 10mM caffeine selectively reduced ICl(Ba) without significant change in IBa. When Ca2+ was the charge carrier, caffeine had little effect on ICl(Ca), and increased the inactivation of ICa. 5. We conclude that, in addition to being regulated by divalent cation entry through Ca2+ channels, the Cl- current is also regulated by G-protein activation. The mechanism of activation of ICl(Ba) may involve Ca2+ release from intracellular stores.

  2. Construction

    DTIC Science & Technology

    2003-01-01

    hot water, appliances, lightening and misc.66 Average and efficient energy costs were determined for each base. The collection of average and...data and the appropriate regional median condominium87 and apartment O&M costs . For new housing projects the energy efficient utility costs were used...supply of domestic skilled laborers and the increasing cost of insurance. The construction industry has always contracted and expanded based

  3. Transnational Higher Education: A Stock Take of Current Activity

    ERIC Educational Resources Information Center

    Naidoo, Vik

    2009-01-01

    Transnational higher education (TNHE) development is not an entirely new international activity in the education services sector. The nature and scale of the global expansion of contemporary TNHE developments are, however, changing substantially. An understanding of this growth is currently largely lacking because of a dearth of comprehensive…

  4. The Current State of Marketing Activity among Higher Education Institutions.

    ERIC Educational Resources Information Center

    Newman, Cynthia M.

    2002-01-01

    Investigated the current state of marketing, marketing research, and planning practices at four-year higher education institutions. Builds upon previous studies by Blackburn (1979) and Goldgehn (1982 and 1989). Determined whether the use and apparent understanding of marketing and its attendant activities by admissions and enrollment management…

  5. The Current State of Marketing Activity among Higher Education Institutions.

    ERIC Educational Resources Information Center

    Newman, Cynthia M.

    2002-01-01

    Investigated the current state of marketing, marketing research, and planning practices at four-year higher education institutions. Builds upon previous studies by Blackburn (1979) and Goldgehn (1982 and 1989). Determined whether the use and apparent understanding of marketing and its attendant activities by admissions and enrollment management…

  6. Fast Delayed Rectifier Potassium Current Required for Circadian Neural Activity

    PubMed Central

    JN, Itri; S, Michel; MJ, Vansteensel; JH, Meijer; CS, Colwell

    2005-01-01

    In mammals, the precise circadian timing of many biological processes depends on the generation of oscillations in neural activity of pacemaker cells in the suprachiasmatic nucleus (SCN). The ionic mechanisms underlying these rhythms are largely unknown. Using the mouse brain slice preparation, we demonstrate that the magnitude of fast delayed rectifier potassium currents exhibits a diurnal rhythm that peaks during the day. Importantly, this rhythm continues in constant darkness, providing the first demonstration of the circadian regulation of an intrinsic voltage–gated current in mammalian cells. Blocking this current prevented the daily rhythm in firing rate in SCN neurons. Kv3.1b and Kv3.2 potassium channels were found to be widely distributed within the SCN with higher expression during the day. We conclude that the fast delayed rectifier is necessary for the circadian modulation of electrical activity in SCN neurons, and represents an important part of the ionic basis for the generation of rhythmic output. PMID:15852012

  7. Current concepts of active vasodilation in human skin

    PubMed Central

    Wong, Brett J.; Hollowed, Casey G.

    2017-01-01

    ABSTRACT In humans, an increase in internal core temperature elicits large increases in skin blood flow and sweating. The increase in skin blood flow serves to transfer heat via convection from the body core to the skin surface while sweating results in evaporative cooling of the skin. Cutaneous vasodilation and sudomotor activity are controlled by a sympathetic cholinergic active vasodilator system that is hypothesized to operate through a co-transmission mechanism. To date, mechanisms of cutaneous active vasodilation remain equivocal despite many years of research by several productive laboratory groups. The purpose of this review is to highlight recent advancements in the field of cutaneous active vasodilation framed in the context of some of the historical findings that laid the groundwork for our current understanding of cutaneous active vasodilation. PMID:28349094

  8. Comparison of excitatory currents activated by different transmitters on crustacean muscle. II. Glutamate-activated currents and comparison with acetylcholine currents present on the same muscle.

    PubMed

    Lingle, C; Auerbach, A

    1983-04-01

    The properties of glutamate-activated excitatory currents on the gm6 muscle from the foregut of the spiny lobsters Panulirus argus and interruptus and the crab Cancer borealis were examined using either noise analysis, analysis of synaptic current decays, or slow iontophoretic currents. The properties of acetylcholine currents activated in nonjunctional regions of the gm6 muscle were also examined. At 12 degrees C and -80 mV, the predominant time constant of power spectra from glutamate-activated current noise was approximately 7 ms and the elementary conductance was approximately 34 pS. At 12 degrees C and -80 mV, the predominant time constant of acetylcholine-activated channels was approximately 11 ms with a conductance of approximately 12 pS. Focally recorded glutamatergic extracellular synaptic currents on the gm6 muscle decayed with time constants of approximately 7-8 ms at 12 degrees C and -80 mV. The decay time constant was prolonged e-fold about every 225-mV hyperpolarization in membrane potential. The Q10 of the time constant of the synaptic current decay was approximately 2.6. The voltage dependence of the steady-state conductance increase activated by iontophoretic application of glutamate has the opposite direction of the steady-state conductance activated by cholinergic agonists when compared on the gm6 muscles. The glutamate-activated conductance increase is diminished with hyperpolarization. The properties of the marine crustacean glutamate channels are discussed in relation to glutamate channels in other organisms and to the acetylcholine channels found on the gm6 muscle and the gm1 muscle of the decapod foregut (Lingle and Auerbach, 1983).

  9. Constructing Media Artifacts in a Social Constructivist Environment to Enhance Students' Environmental Awareness and Activism

    ERIC Educational Resources Information Center

    Karahan, Engin; Roehrig, Gillian

    2015-01-01

    Current science education reforms and policy documents highlight the importance of environmental awareness and perceived need for activism. As "environmental problems are socially constructed in terms of their conceptualized effects on individuals, groups, other living things and systems research based on constructivist principles provides…

  10. Constructing Media Artifacts in a Social Constructivist Environment to Enhance Students' Environmental Awareness and Activism

    ERIC Educational Resources Information Center

    Karahan, Engin; Roehrig, Gillian

    2015-01-01

    Current science education reforms and policy documents highlight the importance of environmental awareness and perceived need for activism. As "environmental problems are socially constructed in terms of their conceptualized effects on individuals, groups, other living things and systems research based on constructivist principles provides…

  11. Dam safety exemplfied by bed diagnostics for the Boguchany HPP currently under construction

    SciTech Connect

    Kalustyan, E. S.

    2011-11-15

    Reliability and safety of water-development works can be ensured by diagnostics of the status of a structure while under construction or in service from results of analysis of data derived from field observations.

  12. Activation of outward K+ currents: effect of VIP in oesophagus

    PubMed Central

    Jury, Jennifer; Daniel, Edwin E

    1999-01-01

    Electrical field stimulations (EFS) of the opossum and canine lower oesophageal sphincters (OLOS and CLOS respectively) and opossum oesophageal body circular muscle (OOBCM) induce non-adrenergic, non-cholinergic (NANC) relaxations of any active tension and NO-mediated hyperpolarization. VIP relaxes the OLOS and CLOS and any tone in OOBCM without major electrophysiological effects. These relaxations are not blocked by NOS inhibitors. Using isolated smooth muscle cells, we tested whether VIP acted through myogenic NO production.Outward currents were similar in OOBCM and OLOS and NO increased them regardless of pipette Ca2+i, from 50–8000 nM. L-NAME or L-NOARG did not block outward currents in OLOS at 200 nM pipette Ca2+.Outward currents in CLOS cells decreased at 200 nM pipette Ca2+ or less but NO donors still increased them. VIP had no effect on outward currents in cells from OOBCM, OLOS or CLOS under conditions of pipette Ca2+ at which NO donors increased outward K+ currents.We conclude, VIP does not mimic electrophysiological effects of NO donors on isolated cells of OOBCM, OLOS or CLOS. VIP relaxes the OLOS and CLOS and inhibits contraction of OOBCM by a mechanism unrelated to release of myogenic NO or an increase in outward current.Also, the different dependence of outward currents of OOBCM and OLOS on pipette Ca2+ from those of CLOS suggests that different K+ channels are involved and that myogenic NO production contributes to K+ channel activity in CLOS but not in OLOS or OOBCM. PMID:10385258

  13. Current research and case work activities of criminalistics in Japan.

    PubMed

    Seta, S

    1996-06-28

    The current research and case work activities of criminalistics in Japan are described. The selected forensic science disciplines are forensic osteology including specialized technology of skull identification, forensic serology, forensic DNA analysis of poisonous materials, forensic hair and fiber analysis, trace evidence analysis, document analysis, forensic psychology mainly concerned with the so-called lie-detector, forensic image analysis, voice print analysis, fire and explosion analysis, forensic engineering, firearm and toolmark analysis. The current activity of the Training Institute of Forensic Science at the National Research Institute of Police Science is also briefly described with special regard to the education and training course of forensic DNA typing analysis. Instruments for analytical and methodological use are listed according to the availability in evidence sample analyses.

  14. Problem of construction of the operator of the electromagnetic current of a nucleus

    SciTech Connect

    Korchin, A.Y.; Shebeko, A.V.

    1984-10-01

    The idea of R. G. Sachs (Phys. Rev. 74, 433 (1948)) in the phenomenological theory of exchange currents in nuclei is developed to obtain an expression for the Hamiltonian of a nucleus. An expression is obtained for the current which has the same isospin structure as the pion and seagull currents in the theory of meson exchange currents. Sachs' result follows for the case of point nucleons.

  15. Fast Inhibition of Glutamate-Activated Currents by Caffeine

    PubMed Central

    Vyleta, Nicholas P.; Smith, Stephen M.

    2008-01-01

    Background Caffeine stimulates calcium-induced calcium release (CICR) in many cell types. In neurons, caffeine stimulates CICR presynaptically and thus modulates neurotransmitter release. Methodology/Principal Findings Using the whole-cell patch-clamp technique we found that caffeine (20 mM) reversibly increased the frequency and decreased the amplitude of miniature excitatory postsynaptic currents (mEPSCs) in neocortical neurons. The increase in mEPSC frequency is consistent with a presynaptic mechanism. Caffeine also reduced exogenously applied glutamate-activated currents, confirming a separate postsynaptic action. This inhibition developed in tens of milliseconds, consistent with block of channel currents. Caffeine (20 mM) did not reduce currents activated by exogenous NMDA, indicating that caffeine block is specific to non-NMDA type glutamate receptors. Conclusions/Significance Caffeine-induced inhibition of mEPSC amplitude occurs through postsynaptic block of non-NMDA type ionotropic glutamate receptors. Caffeine thus has both pre and postsynaptic sites of action at excitatory synapses. PMID:18781199

  16. Workload assessment in building construction related activities in India.

    PubMed

    Maiti, Rina

    2008-11-01

    A field study was conducted to highlight the occupational risk factors related to building construction activities in India among female workers. These workers were engaged in eight different types of activities and related work parameters were studied in detail. From field environmental parameters, the calculated WBGT was obtained as 30.26+/-1.52 degrees C, indicated that these workers worked under a positive heat load condition. Whole day work study was conducted on 11 adult female workers performing concreting operation. They were having age of 28-32 years with 5-7 years of work experience. These workers were mainly performing two types of operations in the field: (A) asymmetric lifting during concreting a boundary wall formwork of a lift unit and (B) carrying the concrete mixture. During asymmetric lifting, the average field working heart rate (HR) was calculated as 124.1+/-12.5 beats min(-1), equivalent to 45.03+/-6.93% of VO(2) max level. These working heart rates (HRs) were significantly (p

  17. Constructing Media Artifacts in a Social Constructivist Environment to Enhance Students' Environmental Awareness and Activism

    NASA Astrophysics Data System (ADS)

    Karahan, Engin; Roehrig, Gillian

    2015-02-01

    Current science education reforms and policy documents highlight the importance of environmental awareness and perceived need for activism. As "environmental problems are socially constructed in terms of their conceptualized effects on individuals, groups, other living things and systems research based on constructivist principles provides not only a coherent framework in which to theorize about learning, but also a context for understanding socially constructed issues" (Palmer and Suggate in Res Pap Educ 19(2), 2004, p. 208). This research study investigated the impacts of the learning processes structured based on the theories of constructionism and social constructivism on students' environmental awareness and perceived need for activism. Students constructed multimedia artifacts expressing their knowledge, attitudes, awareness, and activism about environmental issues through a constructionist design process. In addition, a social networking site was designed and used to promote social interaction among students. Twenty-two high school environmental science students participated in this study. A convergent mixed methods design was implemented to allow for the triangulation of methods by directly comparing and contrasting quantitative results with qualitative findings for corroboration and validation purposes. Using a mixed method approach, quantitative findings are supported with qualitative data (student video projects, writing prompts, blog entries, video projects of the students, observational field notes, and reflective journals) including spontaneous responses in both synchronous and asynchronous conversations on the social network to provide a better understanding of the change in students' environmental awareness and perceived need for activism. The findings of the study indicated that students' environmental awareness and perceived need for activism were improved at different scales (personal, community, global) throughout the constructionist and social

  18. Spatiotemporal order and emergent edge currents in active spinner materials

    PubMed Central

    van Zuiden, Benjamin C.; Paulose, Jayson; Irvine, William T. M.; Bartolo, Denis; Vitelli, Vincenzo

    2016-01-01

    Collections of interacting, self-propelled particles have been extensively studied as minimal models of many living and synthetic systems from bird flocks to active colloids. However, the influence of active rotations in the absence of self-propulsion (i.e., spinning without walking) remains less explored. Here, we numerically and theoretically investigate the behavior of ensembles of self-spinning dimers. We find that geometric frustration of dimer rotation by interactions yields spatiotemporal order and active melting with no equilibrium counterparts. At low density, the spinning dimers self-assemble into a triangular lattice with their orientations phase-locked into spatially periodic phases. The phase-locked patterns form dynamical analogs of the ground states of various spin models, transitioning from the three-state Potts antiferromagnet at low densities to the striped herringbone phase of planar quadrupoles at higher densities. As the density is raised further, the competition between active rotations and interactions leads to melting of the active spinner crystal. Emergent edge currents, whose direction is set by the chirality of the active spinning, arise as a nonequilibrium signature of the transition to the active spinner liquid and vanish when the system eventually undergoes kinetic arrest at very high densities. Our findings may be realized in systems ranging from liquid crystal and colloidal experiments to tabletop realizations using macroscopic chiral grains. PMID:27803323

  19. Adolescents' physical activity is associated with previous and current physical activity practice by their parents.

    PubMed

    Christofaro, Diego Giulliano Destro; Andersen, Lars Bo; Andrade, Selma Maffei de; Barros, Mauro Virgílio Gomes de; Saraiva, Bruna Thamyres Ciccotti; Fernandes, Rômulo Araújo; Ritti-Dias, Raphael Mendes

    2017-07-25

    The purpose of this study was to determine whether parents' current and previous physical activity practice is associated with adolescents' physical activity. The sample was composed of 1231 adolescents (14-17 years), and 1202 mothers and 871 fathers were interviewed. Weight and height of the adolescents were measured. Self-reported parents' weight and height were obtained. The current and previous physical activity levels (Baecke's questionnaire) of parents (during childhood and adolescence) and adolescents' physical activity levels were obtained using a questionnaire. The magnitude of the associations between parent and adolescent physical activity levels was determined by binary logistic regression (adjusted by sex, age, and socioeconomic level of adolescents and education level of parents). The current physical activity practice by parents was associated with adolescents' physical activity (p<0.001). The physical activities reported by parents in their childhood and adolescence were also associated with higher physical activity levels among adolescents. Adolescents whose parents were both physically active in the past and present were six times (OR=6.67 [CI=1.94-22.79]) more likely to be physically active compared to adolescents with no parents who were physically active in the past. The current and previous physical activities of parents were associated with higher levels of physical activity in adolescents, even after controlling for confounding factors. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  20. Calcium activates and inactivates a photoreceptor soma potassium current.

    PubMed Central

    Alkon, D L; Sakakibara, M

    1985-01-01

    Light-induced currents were measured with a two-microelectrode voltage clamp of type B photoreceptor somata, which had been isolated by axotomy from all synaptic interactions as well as from all membranes capable of generating impulse activity. In artificial seawater (ASW), light elicited a transient early inward current, INa+, which depended on Na+o and had a linear current-voltage relation and an extrapolated reversal potential of 30-40 mV (absolute). In 0-Na+ ASW, light elicited a transient short-latency outward current that dependent on K+o, increased exponentially with more positive voltages (greater than or equal to -40 mV), and reversed at -70 to -75 mV. This outward current was not blocked by Ca++ channel blockers (e.g., Cd++, Co++) or substitution of Ba++o, for Ca++o, but was reduced by iontophoretic injection of EGTA. In both ASW and 0-Na+ ASW, light also elicited a delayed, apparently inward current, which was associated with a decreased conductance, depended on K+o, increased exponentially with more positive voltages (greater than or equal to -40 mV), reversed at the equilibrium potential for K+ flux in elevated K+o was eliminated by substitution of Ba++o for Ca++o, and was greatly reduced by Cd++o or Co++o. Thus, light elicited an early Ca++-dependent K+ current, IC, and a prolonged decrease of IC. Iontophoretic injection of Ca++ through a third microelectrode caused prolonged reduction of both IC and the light-induced decrease of IC, but did not alter ICa++ or the current-voltage relation of IC. Ruthenium red (1 microM) in the external medium caused a prolongation of the light-induced decrease of IC. Iontophoretic injection of EGTA often eliminated the light-induced IC decrease while decreasing peak IC (during depolarizing steps to -5 or 0 mV) by less than one-half. EGTA injection, on the average, did not affect steady state IC but reduced the light-induced decrease of steady state IC to approximately one-third of its original magnitude. The prolonged

  1. Current status on tissue factor activation of factor VIIa.

    PubMed

    Persson, Egon; Olsen, Ole H

    2010-04-01

    Free factor VIIa displays a zymogen-like behavior with low intrinsic activity. Formation of a complex between factor VIIa and tissue factor is necessary to enhance the procoagulant activity of factor VIIa, not only by providing membrane localization, substrate exosites and positioning the active site at an appropriate distance above the surface but also by allosteric enhancement of the enzymatic activity, and this event signals initiation of blood coagulation. The interaction is of high affinity and all the domains are engaged at the interface. The crosstalk between the protease domain of factor VIIa, in particular residue Met-306, and the N-terminal domain of tissue factor provides the starting point for the allosteric activation of factor VIIa. The pathway(s) of conformational transitions in factor VIIa ensuing tissue factor binding has not been entirely mapped. The present paper is a brief compilation of our current knowledge of the allosteric mechanism by which tissue factor induces and stabilizes the active conformation of factor VIIa.

  2. Local Anesthetic Inhibits Hyperpolarization-Activated Cationic Currents

    PubMed Central

    Meng, Qing-tao; Xia, Zhong-yuan; Liu, Jin; Bayliss, Douglas A.

    2011-01-01

    Systemic administration of local anesthetics has beneficial perioperative properties and an anesthetic-sparing and antiarrhythmic effect, although the detailed mechanisms of these actions remain unclear. In the present study, we investigated the effects of a local anesthetic, lidocaine, on hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels that contribute to the pacemaker currents in rhythmically oscillating cells of the heart and brain. Voltage-clamp recordings were used to examine the properties of cloned HCN subunit currents expressed in Xenopus laevis oocytes and human embryonic kidney (HEK) 293 cells under control condition and lidocaine administration. Lidocaine inhibited HCN1, HCN2, HCN1-HCN2, and HCN4 channel currents at 100 μM in both oocytes and/or HEK 293 cells; it caused a decrease in both tonic and maximal current (∼30–50% inhibition) and slowed current activation kinetics for all subunits. In addition, lidocaine evoked a hyperpolarizing shift in half-activation voltage (ΔV1/2 of ∼−10 to −14 mV), but only for HCN1 and HCN1-HCN2 channels. By fitting concentration-response data to logistic functions, we estimated half-maximal (EC50) concentrations of lidocaine of ∼30 to 40 μM for the shift in V1/2 observed with HCN1 and HCN1-HCN2; for inhibition of current amplitude, calculated EC50 values were ∼50 to 70 μM for HCN1, HCN2, and HCN1-HCN2 channels. A lidocaine metabolite, monoethylglycinexylidide (100 μM), had similar inhibitory actions on HCN channels. These results indicate that lidocaine potently inhibits HCN channel subunits in dose-dependent manner over a concentration range relevant for systemic application. The ability of local anesthetics to modulate Ih in central neurons may contribute to central nervous system depression, whereas effects on If in cardiac pacemaker cells may contribute to the antiarrhythmic and/or cardiovascular toxic action. PMID:21303986

  3. Improved Active Harmonic Current Elimination Based on Voltage Detection.

    PubMed

    Tan, Tianyuan; Dong, Shuan; Huang, Yingwei; Liu, Jian; Le, Jian; Liu, Kaipei

    2016-01-01

    With the increasing penetration of power electronic equipment in modern residential distribution systems, harmonics mitigation through the distributed generation (DG) interfacing converters has received significant attention. Among recently proposed methods, the so-called active resonance damper (ARD) and harmonic voltage compensator (HVC) based on voltage detection can effectively reduce the harmonic distortions in selected areas of distribution systems. However, it is found out that when traditional ARD algorithm is used to eliminate harmonic current injected by non-linear loads, its performance is constrained by stability problems and can at most eliminate half of the load harmonic currents. Thus, inspired by the duality between ARD and HVC, this paper presents a novel improved resistive active power filter (R-APF) algorithm based on integral-decoupling control. The design guideline for its parameters is then investigated through carefully analyzing the closed-loop poles' trajectory. Computer studies demonstrate that the proposed algorithm can effectively mitigate the load harmonic currents and its performance is much better than traditional ARD based on proportional control.

  4. Improved Active Harmonic Current Elimination Based on Voltage Detection

    PubMed Central

    Tan, Tianyuan; Dong, Shuan; Huang, Yingwei; Liu, Jian; Le, Jian; Liu, Kaipei

    2016-01-01

    With the increasing penetration of power electronic equipment in modern residential distribution systems, harmonics mitigation through the distributed generation (DG) interfacing converters has received significant attention. Among recently proposed methods, the so-called active resonance damper (ARD) and harmonic voltage compensator (HVC) based on voltage detection can effectively reduce the harmonic distortions in selected areas of distribution systems. However, it is found out that when traditional ARD algorithm is used to eliminate harmonic current injected by non-linear loads, its performance is constrained by stability problems and can at most eliminate half of the load harmonic currents. Thus, inspired by the duality between ARD and HVC, this paper presents a novel improved resistive active power filter (R-APF) algorithm based on integral-decoupling control. The design guideline for its parameters is then investigated through carefully analyzing the closed-loop poles’ trajectory. Computer studies demonstrate that the proposed algorithm can effectively mitigate the load harmonic currents and its performance is much better than traditional ARD based on proportional control. PMID:27295213

  5. The construction of airfoil pressure models by the plate method: Achievements, current research, technology development and potential applications

    NASA Technical Reports Server (NTRS)

    Lawing, P. L.

    1985-01-01

    A method of constructing airfoils by inscribing pressure channels on the face of opposing plates, bonding them together to form one plate with integral channels, and contour machining this plate to form an airfoil model is described. The research and development program to develop the bonding technology is described as well as the construction and testing of an airfoil model. Sample aerodynamic data sets are presented and discussed. Also, work currently under way to produce thin airfoils with camber is presented. Samples of the aft section of a 6 percent airfoil with complete pressure instrumentation including the trailing edge are pictured and described. This technique is particularly useful in fabricating models for transonic cryogenic testing, but it should find application in a wide ange of model construction projects, as well as the fabrication of fuel injectors, space hardware, and other applications requiring advanced bonding technology and intricate fluid passages.

  6. Adaptive Current Control Method for Hybrid Active Power Filter

    NASA Astrophysics Data System (ADS)

    Chau, Minh Thuyen

    2016-09-01

    This paper proposes an adaptive current control method for Hybrid Active Power Filter (HAPF). It consists of a fuzzy-neural controller, identification and prediction model and cost function. The fuzzy-neural controller parameters are adjusted according to the cost function minimum criteria. For this reason, the proposed control method has a capability on-line control clings to variation of the load harmonic currents. Compared to the single fuzzy logic control method, the proposed control method shows the advantages of better dynamic response, compensation error in steady-state is smaller, able to online control is better and harmonics cancelling is more effective. Simulation and experimental results have demonstrated the effectiveness of the proposed control method.

  7. Current water resources activities in Alabama, fiscal year 1986

    USGS Publications Warehouse

    Slack, L.J.; Meadows, E.A.

    1986-01-01

    The purpose of this report is to describe the current (as of 1986) water resources activities of the U.S. Geological Survey in Alabama. The responsibilities and objectives of the Survey; organization of the Alabama District; sources of funding; current projects; hydrologic data program; and a selected bibliography of hydrologic reports are presented. Water resources projects are undertaken usually at the request of and with partial funding from another agency, provided: they are high priority problems and generally identified to fall within the mission of the Water Resources Division and they are consistent with the Program Management Plan developed by the Water Resources Division in Alabama to meet the long range plan for hydrologic data in the State. (USGS)

  8. Voltage Dependence of a Neuromodulator-Activated Ionic Current.

    PubMed

    Gray, Michael; Golowasch, Jorge

    2016-01-01

    The neuromodulatory inward current (IMI) generated by crab Cancer borealis stomatogastric ganglion neurons is an inward current whose voltage dependence has been shown to be crucial in the activation of oscillatory activity of the pyloric network of this system. It has been previously shown that IMI loses its voltage dependence in conditions of low extracellular calcium, but that this effect appears to be regulated by intracellular calmodulin. Voltage dependence is only rarely regulated by intracellular signaling mechanisms. Here we address the hypothesis that the voltage dependence of IMI is mediated by intracellular signaling pathways activated by extracellular calcium. We demonstrate that calmodulin inhibitors and a ryanodine antagonist can reduce IMI voltage dependence in normal Ca(2+), but that, in conditions of low Ca(2+), calmodulin activators do not restore IMI voltage dependence. Further, we show evidence that CaMKII alters IMI voltage dependence. These results suggest that calmodulin is necessary but not sufficient for IMI voltage dependence. We therefore hypothesize that the Ca(2+)/calmodulin requirement for IMI voltage dependence is due to an active sensing of extracellular calcium by a GPCR family calcium-sensing receptor (CaSR) and that the reduction in IMI voltage dependence by a calmodulin inhibitor is due to CaSR endocytosis. Supporting this, preincubation with an endocytosis inhibitor prevented W7 (N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride)-induced loss of IMI voltage dependence, and a CaSR antagonist reduced IMI voltage dependence. Additionally, myosin light chain kinase, which is known to act downstream of the CaSR, seems to play a role in regulating IMI voltage dependence. Finally, a Gβγ-subunit inhibitor also affects IMI voltage dependence, in support of the hypothesis that this process is regulated by a G-protein-coupled CaSR.

  9. Voltage Dependence of a Neuromodulator-Activated Ionic Current123

    PubMed Central

    2016-01-01

    Abstract The neuromodulatory inward current (IMI) generated by crab Cancer borealis stomatogastric ganglion neurons is an inward current whose voltage dependence has been shown to be crucial in the activation of oscillatory activity of the pyloric network of this system. It has been previously shown that IMI loses its voltage dependence in conditions of low extracellular calcium, but that this effect appears to be regulated by intracellular calmodulin. Voltage dependence is only rarely regulated by intracellular signaling mechanisms. Here we address the hypothesis that the voltage dependence of IMI is mediated by intracellular signaling pathways activated by extracellular calcium. We demonstrate that calmodulin inhibitors and a ryanodine antagonist can reduce IMI voltage dependence in normal Ca2+, but that, in conditions of low Ca2+, calmodulin activators do not restore IMI voltage dependence. Further, we show evidence that CaMKII alters IMI voltage dependence. These results suggest that calmodulin is necessary but not sufficient for IMI voltage dependence. We therefore hypothesize that the Ca2+/calmodulin requirement for IMI voltage dependence is due to an active sensing of extracellular calcium by a GPCR family calcium-sensing receptor (CaSR) and that the reduction in IMI voltage dependence by a calmodulin inhibitor is due to CaSR endocytosis. Supporting this, preincubation with an endocytosis inhibitor prevented W7 (N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride)-induced loss of IMI voltage dependence, and a CaSR antagonist reduced IMI voltage dependence. Additionally, myosin light chain kinase, which is known to act downstream of the CaSR, seems to play a role in regulating IMI voltage dependence. Finally, a Gβγ-subunit inhibitor also affects IMI voltage dependence, in support of the hypothesis that this process is regulated by a G-protein-coupled CaSR. PMID:27257619

  10. Accuracy in interpersonal expectations: a reflection-construction analysis of current and classic research.

    PubMed

    Jussim, L

    1993-12-01

    Research and theory on interpersonal expectations have been dominated by a strong social constructivist perspective arguing that expectancies are often inaccurate and a major force in the creation of social reality. The reflection-construction model is an attempt to examine these strong claims conceptually and empirically. This model assumes that social perception includes both constructivist phenomena and accuracy. When this model is used as a framework for interpreting research on teacher expectations and on the role of stereotypes in person perception, it shows that interpersonal expectancies are often accurate, and usually lead only to relatively small biases and self-fulfilling prophecies. The model also is used to interpret research on expectancies that has provided some of the foundations for the strong constructivist perspective. This reflection-construction analysis shows that even those studies strongly suggest that people's expectations generally will be highly accurate.

  11. Current views of health care design and construction: practical implications for safer, cleaner environments.

    PubMed

    Bartley, Judene M; Olmsted, Russell N; Haas, Janet

    2010-06-01

    Infection preventionists (IP) play an increasingly important role in preventing health care-associated infection in the physical environment associated with new construction or renovation of health care facilities. The Guidelines for Design and Construction of Hospital and Healthcare Facilities, 2010, formerly known as "AIA Guidelines" was the origin of the "infection control risk assessment" now required by multiple agencies. These Guidelines represent minimum US health care standards and provide guidance on best practices. They recognize that the built environment has a profound affect on health and the natural environment and require that health care facilities be designed to "first, do no harm." This review uses the Guidelines as a blueprint for IPs' role in design and construction, updating familiar concepts to the 2010 edition with special emphasis on IP input into design given its longer range impact on health care-associated infection prevention while linking to safety and sustainability. Section I provides an overview of disease transmission risks from the built environment and related costs, section II presents a broad view of design and master planning, and section III addresses the detailed design strategies for infection prevention specifically addressed in the 2010 Facility Guidelines Institute edition.

  12. Data Mining Activities for Bone Discipline - Current Status

    NASA Technical Reports Server (NTRS)

    Sibonga, J. D.; Pietrzyk, R. A.; Johnston, S. L.; Arnaud, S. B.

    2008-01-01

    The disciplinary goals of the Human Research Program are broadly discussed. There is a critical need to identify gaps in the evidence that would substantiate a skeletal health risk during and after spaceflight missions. As a result, data mining activities will be engaged to gather reviews of medical data and flight analog data and to propose additional measures and specific analyses. Several studies are briefly reviewed which have topics that partially address these gaps in knowledge, including bone strength recovery with recovery of bone mass density, current renal stone formation knowledge, herniated discs, and a review of bed rest studies conducted at Ames Human Research Facility.

  13. The effect of Peltier heat during current activated densification

    NASA Astrophysics Data System (ADS)

    Becker, A.; Angst, S.; Schmitz, A.; Engenhorst, M.; Stoetzel, J.; Gautam, D.; Wiggers, H.; Wolf, D. E.; Schierning, G.; Schmechel, R.

    2012-07-01

    It is shown that current-activated pressure-assisted densification (CAPAD) is sensitive to the Peltier effect. Under CAPAD, the Peltier effect leads to a significant redistribution of heat within the sample during the densification. The densification of highly p-doped silicon nanoparticles during CAPAD and the properties of the obtained samples are investigated experimentally and by computer simulation. Both, simulation and experiments, indicate clearly a higher temperature on the cathode side and a decreasing temperature from the center to the outer shell. Furthermore, computer simulations provide additional insights into the temperature profile which explain the anisotropic properties of the measured sample.

  14. Design Piracy: Student Perceptions of a Constructive Controversy Activity

    ERIC Educational Resources Information Center

    Marcketti, Sara B.

    2007-01-01

    Optimal learning occurs when students are interested in the subject matter, are motivated with challenging and quality learning opportunities, and when immersed in atmospheres that make learning enjoyable. One technique to promote optimal learning is through the use of constructive controversies. The purpose of this study was to provide an example…

  15. Transtheoretical Model Constructs for Physical Activity Behavior are Invariant across Time among Ethnically Diverse Adults in Hawaii.

    PubMed

    Geller, Karly S; Nigg, Claudio R; Motl, Robert W; Horwath, Caroline; Dishman, Rod K

    2012-09-01

    OBJECTIVES: Physical activity (PA) research applying the Transtheoretical Model (TTM) to examine group differences and/or change over time requires preliminary evidence of factorial validity and invariance. The current study examined the factorial validity and longitudinal invariance of TTM constructs recently revised for PA. METHOD: Participants from an ethnically diverse sample in Hawaii (N=700) completed questionnaires capturing each TTM construct. RESULTS: Factorial validity was confirmed for each construct using confirmatory factor analysis with full-information maximum likelihood. Longitudinal invariance was evidenced across a shorter (3-month) and longer (6-month) time period via nested model comparisons. CONCLUSIONS: The questionnaires for each validated TTM construct are provided, and can now be generalized across similar subgroups and time points. Further validation of the provided measures is suggested in additional populations and across extended time points.

  16. Transtheoretical Model Constructs for Physical Activity Behavior are Invariant across Time among Ethnically Diverse Adults in Hawaii

    PubMed Central

    Nigg, Claudio R; Motl, Robert W; Horwath, Caroline; Dishman, Rod K

    2012-01-01

    Objectives Physical activity (PA) research applying the Transtheoretical Model (TTM) to examine group differences and/or change over time requires preliminary evidence of factorial validity and invariance. The current study examined the factorial validity and longitudinal invariance of TTM constructs recently revised for PA. Method Participants from an ethnically diverse sample in Hawaii (N=700) completed questionnaires capturing each TTM construct. Results Factorial validity was confirmed for each construct using confirmatory factor analysis with full-information maximum likelihood. Longitudinal invariance was evidenced across a shorter (3-month) and longer (6-month) time period via nested model comparisons. Conclusions The questionnaires for each validated TTM construct are provided, and can now be generalized across similar subgroups and time points. Further validation of the provided measures is suggested in additional populations and across extended time points. PMID:22778669

  17. Current products and practices: curriculum development in orthodontic specialist registrar training: can orthodontics achieve constructive alignment?

    PubMed

    Chadwick, S M

    2004-09-01

    This paper aims to encourage a debate on the learning outcomes that have been developed for orthodontic specialist education. In outcome-based education the learning outcomes are clearly defined. They determine curriculum content and its organization, the teaching and learning approaches, the assessment techniques and hope to focus the minds of the students on ensuring all the learning outcomes are met. In Orthodontic Specialist Registrar training, whether constructive alignment can be achieved depends on the relationship between these aspects of the education process and the various bodies responsible for their delivery in the UK.

  18. Undergraduate Student Construction and Interpretation of Graphs in Physics Lab Activities

    ERIC Educational Resources Information Center

    Nixon, Ryan S.; Godfrey, T. J.; Mayhew, Nicholas T.; Wiegert, Craig C.

    2016-01-01

    Lab activities are an important element of an undergraduate physics course. In these lab activities, students construct and interpret graphs in order to connect the procedures of the lab with an understanding of the related physics concepts. This study investigated undergraduate students' construction and interpretation of graphs with best-fit…

  19. Undergraduate Student Construction and Interpretation of Graphs in Physics Lab Activities

    ERIC Educational Resources Information Center

    Nixon, Ryan S.; Godfrey, T. J.; Mayhew, Nicholas T.; Wiegert, Craig C.

    2016-01-01

    Lab activities are an important element of an undergraduate physics course. In these lab activities, students construct and interpret graphs in order to connect the procedures of the lab with an understanding of the related physics concepts. This study investigated undergraduate students' construction and interpretation of graphs with best-fit…

  20. Design and construction of a Faraday cup for measurement of small electronic currents

    NASA Technical Reports Server (NTRS)

    Veyssiere, A.

    1985-01-01

    The design of a device to measure and integrate very small currents generated by the impact of a charged particle beam upon a Faraday cut is described. The main component is a graphite block capable of stopping practically all the incident changes. The associated electronic apparatus required to measure better than 10/13 ampere with a precision of 10/0 is described.

  1. Constructing a New Taxonomy of Change: Michigan Administrators' Perspectives on Current Change Processes.

    ERIC Educational Resources Information Center

    Jenlink, Patrick M.; Kinnucan-Welsch, Kathryn

    1995-01-01

    Examines the perspectives of administrators in Michigan school districts engaged in change processes. Responses from 83 administrators suggest a framing mechanism, or taxonomy, that represents the current state of change efforts in the state. First-wave, or state-mandated, change is driving most reform in Michigan at present. (SLD)

  2. Active debris removal: Recent progress and current trends

    NASA Astrophysics Data System (ADS)

    Bonnal, Christophe; Ruault, Jean-Marc; Desjean, Marie-Christine

    2013-04-01

    According to all available findings at international level, the Kessler syndrome, increase of the number of space debris in Low Earth Orbits due to mutual collisions, appears now to be a fact, triggered mainly by several major break-ups in orbit which occurred since 2007. The time may have come to study how to clean this fundamentally useful orbital region in an active way. CNES has studied potential solutions for more than 12 years! The paper aims at reviewing the current status of these activities. The high level requirements are fundamental, and have to be properly justified. The working basis, as confirmed through IADC studies consists in the removal of 5-10 integer objects from the overcrowded orbits, spent upper stages or old satellites, as identified by NASA. The logic of CNES activities consider a stepped approach aiming at progressively gaining the required Technological Readiness Level on the features required for Active Debris Removal which have not yet been demonstrated in orbit. The rendezvous with a non-cooperative, un-prepared, tumbling debris is essential. Following maturation gained with Research and Technology programs, a set of small orbital demonstrators could enable a confidence high enough to perform a full end to end demonstration performing the de-orbiting of a large debris and paving the way for the development of a first generation operational de-orbiter. The internal CNES studies, led together by the Toulouse Space Centre and the Paris Launcher Directorate, have started in 2008 and led to a detailed System Requirements Document used for the Industrial studies. Three industrial teams did work under CNES contract during 2011, led by Thales Alenia Space, Bertin Technologies and Astrium Space Transportation, with numerous sub-contractors. Their approaches were very rich, complementary, and innovative. The second phase of studies began mid-2012. Some key questions nevertheless have to be resolved, and correspond generally to current IADC

  3. Introduction to the Special Series: Current Directions for Measuring Parenting Constructs to Inform Prevention Science.

    PubMed

    Lindhiem, Oliver; Shaffer, Anne

    2017-04-01

    Parenting behaviors are multifaceted and dynamic and therefore challenging to quantify. Measurement methods have critical implications for study results, particularly for prevention trials designed to modify parenting behaviors. Although multiple approaches can complement one another and contribute to a more complete understanding of prevention trials, the assumptions and implications of each approach are not always clearly addressed. Greater attention to the measurement of complex constructs such as parenting is needed to advance the field of prevention science. This series examines the challenges of measuring changes in parenting behaviors in the context of prevention trials. All manuscripts in the special series address measurement issues and make practical recommendations for prevention researchers. Manuscripts in this special series include (1) empirical studies that demonstrate novel measurement approaches, (2) re-analyses of prevention trial outcome data directly comparing and contrasting two or more methods, and (3) a statistical primer and practical guide to analyzing proportion data.

  4. Current activities handbook: formerly utilized sites remedial action program

    SciTech Connect

    1981-02-27

    This volume is one of a series produced under contract with the DOE, by Politech Corporation to develop a legislative and regulatory data base to assist the FUSRAP management in addressing the institutional and socioeconomic issues involved in carrying out the Formerly Utilized Sites Remedial Action Program. This Information Handbook series contains information about all relevant government agencies at the Federal and state levels, the pertinent programs they administer, each affected state legislature, and current Federal and state legislative and regulatory initiatives. This volume is a compilation of information about the activities each of the thirteen state legislatures potentially affected by the Formerly Utilized Sites Remedial Action Program. It contains a description of the state legislative procedural rules and a schedule of each legislative session; a summary of pending relevant legislation; the name and telephone number of legislative and state agency contacts; and the full text of all bills identified.

  5. Current Reactor Physics Benchmark Activities at the Idaho National Laboratory

    SciTech Connect

    John D. Bess; Margaret A. Marshall; Mackenzie L. Gorham; Joseph Christensen; James C. Turnbull; Kim Clark

    2011-11-01

    The International Reactor Physics Experiment Evaluation Project (IRPhEP) [1] and the International Criticality Safety Benchmark Evaluation Project (ICSBEP) [2] were established to preserve integral reactor physics and criticality experiment data for present and future research. These valuable assets provide the basis for recording, developing, and validating our integral nuclear data, and experimental and computational methods. These projects are managed through the Idaho National Laboratory (INL) and the Organisation for Economic Co-operation and Development Nuclear Energy Agency (OECD-NEA). Staff and students at the Department of Energy - Idaho (DOE-ID) and INL are engaged in the development of benchmarks to support ongoing research activities. These benchmarks include reactors or assemblies that support Next Generation Nuclear Plant (NGNP) research, space nuclear Fission Surface Power System (FSPS) design validation, and currently operational facilities in Southeastern Idaho.

  6. Simulation of current-activated pressure-assisted densification

    NASA Astrophysics Data System (ADS)

    Wolf, Dietrich; Angst, Sebastian; Schierning, Gabi

    2013-03-01

    Cohesive particles usually form very porous agglomerates. They support loads up to a consolidation pressure, which increases with decreasing particle size. Compaction of nano-powders can therefore be very costly and time consuming. If the particles are electrically conducting, which is the case e.g. for novel nano-structured thermoelectric materials, the technique of current-activated pressure-assisted densification (CAPAD) turns out to have many advantages. Electrical power deposited locally as Joule heat lowers the consolidation pressure such that particles fill nearby pores. This process leads to fast, scalable densification without much coarsening. Simulations are presented which address the influence of correlations on density and conductivity. They also take thermal conductivity and Peltier coefficient into account. Funded by DFG within the Priority Programme SPP 1386 (Nanostructured Thermoelectrics).

  7. Serbia National Poison Control Centre: organization and current activities.

    PubMed

    Jovanović, Dugan; Joksović, Dragan; Vucinić, Savica; Todorović, Veljko; Segrt, Zoran; Kilibarda, Vesna; Bokonjić, Dubravko

    2005-01-01

    Ministry of Health of the former Federal Republic of Yugoslavia established the National Poison Control Centre in 1995. However, that was only the formally solution since clinical, analytical and experimental services in toxicology had worked independently for at least 40 years. Besides the Headquarters, NPCC has currently 2 main units, the Clinic of Emergency and Clinical Toxicology and Pharmacology and the Institute of Toxicology and Pharmacology. The latter is consisted of Toxicological Information Department, Department of Analytical Toxicology and Department of Experimental Toxicology and Pharmacology. The Mobile Toxicological Chemical Unit is a separate department that is activated from personnel of the NPCC in a case of chemical accidents and/or disasters. Clinical, information and analytical parts of NPCC have a 365-day/24-hour working service. The Clinic of Emergency and Clinical Toxicology and Pharmacology is a place where the intoxicated patients are treated, including those that need the intensive care measures. Toxicological Information Department uses the data from a self-made computer Database for different information purposes. Department of Analytical Toxicology is equipped with a lot of contemporary analytical equipment that is giving the opportunity of identification and quantification of chemicals/metabolites/degradation products in biological material, food, water, air and soil. Basic pharmacological and toxicological research of chemicals and pre-clinical investigations of antidotes are realized in the Department of Experimental Toxicology and Pharmacology. In terms of medical prevention and rational treatment of human poison exposures in Serbia, the current organization of NPCC has so far proven to be effective.

  8. [Ecological demonstration activity and eco-civilization construction mode: review and prospects].

    PubMed

    Mao, Hui-ping; He, Xuan; He, Jia; Niu, Dong-jie; Bao, Cun-kuan

    2013-04-01

    Ecological civilization is to normalize human development behaviors to harmonize the relationships between social and ecological development and eco-environment protection. In this paper, a comparative analysis was made on the ecological demonstration activities of ecological demonstration areas led by the Ministry of Environmental Protection, exemplar cities of national environmental protection, and ecological provinces, cities, and counties. It was considered that all the ecological demonstration activities had the problems of lacking pertinence of construction goals, disordered construction subjects, inefficient construction processes, and lacking continuous incentive mechanisms of assessment. In the meantime, through the analysis of the connotations of eco-civilization, the relationships between eco-civilization and eco-demonstration constructions were approached, and the eco-civilization construction mode was put forward in terms of construction goal, construction subject, and construction processes and assessment. The construction mode included the construction goal based on regional characteristics; the synergistic cooperation of construction subjects, the expanding ways of public participation, and the establishment of evaluation system for comprehensively measuring the 'actions and results'.

  9. Learning from Instructional Explanations: Effects of Prompts Based on the Active-Constructive-Interactive Framework

    PubMed Central

    Roelle, Julian; Müller, Claudia; Roelle, Detlev; Berthold, Kirsten

    2015-01-01

    Although instructional explanations are commonly provided when learners are introduced to new content, they often fail because they are not integrated into effective learning activities. The recently introduced active-constructive-interactive framework posits an effectiveness hierarchy in which interactive learning activities are at the top; these are then followed by constructive and active learning activities, respectively. Against this background, we combined instructional explanations with different types of prompts that were designed to elicit these learning activities and tested the central predictions of the active-constructive-interactive framework. In Experiment 1, N = 83 students were randomly assigned to one of four combinations of instructional explanations and prompts. To test the active < constructive learning hypothesis, the learners received either (1) complete explanations and engaging prompts designed to elicit active activities or (2) explanations that were reduced by inferences and inference prompts designed to engage learners in constructing the withheld information. Furthermore, in order to explore how interactive learning activities can be elicited, we gave the learners who had difficulties in constructing the prompted inferences adapted remedial explanations with either (3) unspecific engaging prompts or (4) revision prompts. In support of the active < constructive learning hypothesis, we found that the learners who received reduced explanations and inference prompts outperformed the learners who received complete explanations and engaging prompts. Moreover, revision prompts were more effective in eliciting interactive learning activities than engaging prompts. In Experiment 2, N = 40 students were randomly assigned to either (1) a reduced explanations and inference prompts or (2) a reduced explanations and inference prompts plus adapted remedial explanations and revision prompts condition. In support of the constructive < interactive

  10. Learning from instructional explanations: effects of prompts based on the active-constructive-interactive framework.

    PubMed

    Roelle, Julian; Müller, Claudia; Roelle, Detlev; Berthold, Kirsten

    2015-01-01

    Although instructional explanations are commonly provided when learners are introduced to new content, they often fail because they are not integrated into effective learning activities. The recently introduced active-constructive-interactive framework posits an effectiveness hierarchy in which interactive learning activities are at the top; these are then followed by constructive and active learning activities, respectively. Against this background, we combined instructional explanations with different types of prompts that were designed to elicit these learning activities and tested the central predictions of the active-constructive-interactive framework. In Experiment 1, N = 83 students were randomly assigned to one of four combinations of instructional explanations and prompts. To test the active < constructive learning hypothesis, the learners received either (1) complete explanations and engaging prompts designed to elicit active activities or (2) explanations that were reduced by inferences and inference prompts designed to engage learners in constructing the withheld information. Furthermore, in order to explore how interactive learning activities can be elicited, we gave the learners who had difficulties in constructing the prompted inferences adapted remedial explanations with either (3) unspecific engaging prompts or (4) revision prompts. In support of the active < constructive learning hypothesis, we found that the learners who received reduced explanations and inference prompts outperformed the learners who received complete explanations and engaging prompts. Moreover, revision prompts were more effective in eliciting interactive learning activities than engaging prompts. In Experiment 2, N = 40 students were randomly assigned to either (1) a reduced explanations and inference prompts or (2) a reduced explanations and inference prompts plus adapted remedial explanations and revision prompts condition. In support of the constructive < interactive

  11. Constructing Integrable High-pressure Full-current Free-boundary Stellarator Magnetohydrodynamic Equilibrium Solutions

    SciTech Connect

    S.R. Hudson; D.A. Monticello; A.H. Reiman; D.J. Strickler; S.P. Hirshman; L-P. Ku; E. Lazarus; A. Brooks; M.C. Zarnstorff; A.H. Boozer; G-Y. Fu; and G.H. Neilson

    2003-09-15

    For the (non-axisymmetric) stellarator class of plasma confinement devices to be feasible candidates for fusion power stations it is essential that, to a good approximation, the magnetic field lines lie on nested flux surfaces; however, the inherent lack of a continuous symmetry implies that magnetic islands responsible for breaking the smooth topology of the flux surfaces are guaranteed to exist. Thus, the suppression of magnetic islands is a critical issue for stellarator design, particularly for small aspect ratio devices. Pfirsch-Schluter currents, diamagnetic currents, and resonant coil fields contribute to the formation of magnetic islands, and the challenge is to design the plasma and coils such that these effects cancel. Magnetic islands in free-boundary high-pressure full-current stellarator magnetohydrodynamic equilibria are suppressed using a procedure based on the Princeton Iterative Equilibrium Solver [Reiman and Greenside, Comp. Phys. Comm. 43 (1986) 157] which iterate s the equilibrium equations to obtain the plasma equilibrium. At each iteration, changes to a Fourier representation of the coil geometry are made to cancel resonant fields produced by the plasma. The changes are constrained to preserve certain measures of engineering acceptability and to preserve the stability of ideal kink modes. As the iterations continue, the coil geometry and the plasma simultaneously converge to an equilibrium in which the island content is negligible, the plasma is stable to ideal kink modes, and the coils satisfy engineering constraints. The method is applied to a candidate plasma and coil design for the National Compact Stellarator Experiment [Reiman, et al., Phys. Plasmas 8 (May 2001) 2083].

  12. Constructing Integrable Full-pressure Full-current Free-boundary Stellarator Magnetohydrodynamic Equilibria

    NASA Astrophysics Data System (ADS)

    Hudson, S. R.; Monticello, D. A.; Reiman, A. H.; Strickler, D. J.; Hirshman, S. P.

    2003-06-01

    For the (non-axisymmetric) stellarator class of plasma confinement devices to be feasible candidates for fusion power stations it is essential that, to a good approximation, the magnetic field lines lie on nested flux surfaces; however, the inherent lack of a continuous symmetry implies that magnetic islands are guaranteed to exist. Magnetic islands break the smooth topology of nested flux surfaces and chaotic field lines result when magnetic islands overlap. An analogous case occurs with 11/2-dimension Hamiltonian systems where resonant perturbations cause singularities in the transformation to action-angle coordinates and destroy integrability. The suppression of magnetic islands is a critical issue for stellarator design, particularly for small aspect ratio devices. Techniques for `healing' vacuum fields and fixed-boundary plasma equilibria have been developed, but what is ultimately required is a procedure for designing stellarators such that the self-consistent plasma equilibrium currents and the coil currents combine to produce an integrable magnetic field, and such a procedure is presented here for the first time. Magnetic islands in free-boundary full-pressure full-current stellarator magnetohydrodynamic equilibria are suppressed using a procedure based on the Princeton Iterative Equilibrium Solver [A.H.Reiman & H.S.Greenside, Comp. Phys. Comm., 43:157, 1986.] which iterates the equilibrium equations to obtain the plasma equilibrium. At each iteration, changes to a Fourier representation of the coil geometry are made to cancel resonant fields produced by the plasma. As the iterations continue, the coil geometry and the plasma simultaneously converge to an equilibrium in which the island content is negligible. The method is applied to a candidate plasma and coil design for the National Compact Stellarator eXperiment [G.H.Neilson et.al., Phys. Plas., 7:1911, 2000.].

  13. Control and Calibration of a Staubli RX130 Robotic Arm for Construction of Surface Current Coils

    NASA Astrophysics Data System (ADS)

    Vanmeter, Patrick; Crawford, Christopher; Guler, Emre; Fugal, Mario; Irvin, Bradley

    2013-10-01

    Precision low energy neutron experiments require extremely uniform magnetic fields for manipulating the neutron spin. Such fields can be generated with surface current coils-precision 3-dimensional printed circuits. We are developing a facility to etch out these circuits on copper-plated curved forms using a high-speed spindle attached to the end-effector of a Staubli RX130 six-axis robotic arm. We describe our mathematical model of the robotic links and the software system we designed to control the motion of the arm and to prevent collisions during actuations. We developed a calibration procedure to achieve accuracy of 30 microns in the position of drill.

  14. Active adhesion concepts for in-orbit structural construction

    NASA Technical Reports Server (NTRS)

    Park, K. C.; Natori, M. C.

    1992-01-01

    The in-orbit assembly of structural elements is presently addressed by means of a continuum-based theory of active-adhesion contact/impact which assumes the manufacturability of active adhesion elements by piezoelectric (and similarly behaving) materials. Block bonding characteristics can furnish an effective alternative to optimal control-based, impact surge force-mitigation strategies, especially in the numerous nonsmooth control problems that are difficult to synthesize and implement. Attention is given to design concepts employing combined serial/parallel-bonded active adhesion elements composed of cascaded piezoelectric devices.

  15. Proton activity of the Sun in current solar cycle 24

    NASA Astrophysics Data System (ADS)

    Li, Chuan; Miroshnichenko, Leonty I.; Fang, Cheng

    2015-07-01

    We present a study of seven large solar proton events in the current solar cycle 24 (from 2009 January up to the current date). They were recorded by the GOES spacecraft with the highest proton fluxes being over 200 pfu for energies >10 MeV. In situ particle measurements show that: (1) The profiles of the proton fluxes are highly dependent on the locations of their solar sources, namely flares or coronal mass ejections (CMEs), which confirms the “heliolongitude rules” associated with solar energetic particle fluxes; (2) The solar particle release (SPR) times fall in the decay phase of the flare emission, and are in accordance with the times when the CMEs travel to an average height of 7.9 solar radii; and (3) The time differences between the SPR and the flare peak are also dependent on the locations of the solar active regions. The results tend to support the scenario of proton acceleration by the CME-driven shock, even though there exists a possibility of particle acceleration at the flare site, with subsequent perpendicular diffusion of accelerated particles in the interplanetary magnetic field. We derive the integral time-of-maximum spectra of solar protons in two forms: a single power-law distribution and a power law roll-over with an exponential tail. It is found that the unique ground level enhancement that occurred in the event on 2012 May 17 displays the hardest spectrum and the largest roll-over energy which may explain why this event could extend to relativistic energies. Supported by the National Natural Science Foundation of China.

  16. Electric-current Neutralization, Magnetic Shear, and Eruptive Activity in Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Sun, Xudong; Török, Tibor; Titov, Viacheslav S.; Leake, James E.

    2017-09-01

    The physical conditions that determine whether or not solar active regions (ARs) produce strong flares and coronal mass ejections (CMEs) are not yet well understood. Here, we investigate the association between electric-current neutralization, magnetic shear along polarity inversion lines (PILs), and eruptive activity in four ARs: two emerging and two well-developed ones. We find that the CME-producing ARs are characterized by a strongly non-neutralized total current, while the total current in the ARs that did not produce CMEs is almost perfectly neutralized. The difference in the PIL shear between these two groups is much less pronounced, which suggests that the degree of current neutralization may serve as a better proxy for assessing the ability of ARs to produce CMEs.

  17. Neutralization of Electric Current, Magnetic Shear, and Eruptive Activity in Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Sun, Xudong; Torok, Tibor; Titov, Viacheslav; Leake, James E.

    2017-08-01

    There has been an ongoing debate on whether or not the electric currents in solar active regions (ARs) are neutralized. Current-neutralization means that the direct coronal currents that connect the AR polarity centers are surrounded by return currents of equal total strength and opposite direction, i.e. the net current is zero. Using data from SDO/HMI, we analyze the direct and return currents in four ARs; two eruptive ones and two non-eruptive ones. The eruptive ARs produced strong flares and CMEs (successful eruptions), while the non-eruptive ARs include one quiet AR that produced no strong eruptions and one that produced a series of failed eruptions. It is found that the eruptive ARs have strong net currents and large shear of the magnetic field near their polarity inversion lines (PILs). In contrast, the currents in the non-eruptive ARs are well neutralized, and the PIL-shear is rather small. This agrees with MHD simulations that demonstrate a relationship between the level of current neutralization and the amount of magnetic shear near the PIL. We discuss the implications of these results for the capability of ARs to produce strong eruptions.

  18. 25 CFR 1000.244 - May the Secretary suspend construction activities under an AFA?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... an AFA? 1000.244 Section 1000.244 Indians OFFICE OF THE ASSISTANT SECRETARY, INDIAN AFFAIRS... construction activities under an AFA? (a) The Secretary may require a Tribe/Consortium to suspend certain work under a construction portion of an AFA for up to 30 days only if: (1) Site conditions adversely...

  19. 25 CFR 1000.244 - May the Secretary suspend construction activities under an AFA?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... an AFA? 1000.244 Section 1000.244 Indians OFFICE OF THE ASSISTANT SECRETARY, INDIAN AFFAIRS... construction activities under an AFA? (a) The Secretary may require a Tribe/Consortium to suspend certain work under a construction portion of an AFA for up to 30 days only if: (1) Site conditions adversely...

  20. 25 CFR 1000.244 - May the Secretary suspend construction activities under an AFA?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... an AFA? 1000.244 Section 1000.244 Indians OFFICE OF THE ASSISTANT SECRETARY, INDIAN AFFAIRS... construction activities under an AFA? (a) The Secretary may require a Tribe/Consortium to suspend certain work under a construction portion of an AFA for up to 30 days only if: (1) Site conditions adversely...

  1. 25 CFR 1000.244 - May the Secretary suspend construction activities under an AFA?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... an AFA? 1000.244 Section 1000.244 Indians OFFICE OF THE ASSISTANT SECRETARY, INDIAN AFFAIRS... construction activities under an AFA? (a) The Secretary may require a Tribe/Consortium to suspend certain work under a construction portion of an AFA for up to 30 days only if: (1) Site conditions adversely...

  2. 25 CFR 1000.244 - May the Secretary suspend construction activities under an AFA?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... an AFA? 1000.244 Section 1000.244 Indians OFFICE OF THE ASSISTANT SECRETARY, INDIAN AFFAIRS... construction activities under an AFA? (a) The Secretary may require a Tribe/Consortium to suspend certain work under a construction portion of an AFA for up to 30 days only if: (1) Site conditions adversely...

  3. An Instructional Playground for the Handicapped Using Tires as Inexpensive Playground Equipment: Activity and Construction Manual.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Special Education Instructional Materials Center.

    The manual explains how special education students in an occupational program used tires to construct an inexpensive instructional playground for handicapped elementary school pupils. Presented in two sections with accompanying pictures or diagrams are activity ideas for using the tires in a variety of configurations (Part 1) and construction and…

  4. Fantasy Activity and the Televiewing Event: Considerations for an Information Processing Construct of Involvement.

    ERIC Educational Resources Information Center

    Lindlof, Thomas R.

    The similarities between television viewing and fantasy activity (daydreaming, reverie, mind-wandering, internal dialogue) more than warrant the building of a theoretical construct, especially in the context of recent empirical research on television viewing consequences. A construct of the television viewing process, based on cognitive theories…

  5. Fantasy Activity and the Televiewing Event: Considerations for an Information Processing Construct of Involvement.

    ERIC Educational Resources Information Center

    Lindlof, Thomas R.

    The similarities between television viewing and fantasy activity (daydreaming, reverie, mind-wandering, internal dialogue) more than warrant the building of a theoretical construct, especially in the context of recent empirical research on television viewing consequences. A construct of the television viewing process, based on cognitive theories…

  6. Circuits constructed from identified Aplysia neurons exhibit multiple patterns of persistent activity.

    PubMed Central

    Kleinfeld, D; Raccuia-Behling, F; Chiel, H J

    1990-01-01

    We have used identified neurons from the abdominal ganglion of the mollusc Aplysia to construct and analyze two circuits in vitro. Each of these circuits was capable of producing two patterns of persistent activity; that is, they had bistable output states. The output could be switched between the stable states by a brief, external input. One circuit consisted of cocultured L10 and left upper quadrant (LUQ) neurons that formed reciprocal, inhibitory connections. In one stable state L10 was active and the LUQ was quiescent, whereas in the other stable state L10 was quiescent and the LUQ was active. A second circuit consisted of co-cultured L7 and L12 neurons that formed reciprocal, excitatory connections. In this circuit, both cells were quiescent in one stable state and both cells fired continuously in the other state. Bistable output in both circuits resulted from the nonlinear firing characteristics of each neuron and the feedback between the two neurons. We explored how the stability of the neuronal output could be controlled by the background currents injected into each neuron. We observed a relatively well-defined range of currents for which bistability occurred, consistent with the values expected from the measured strengths of the connections and a simple model. Outside of the range, the output was stable in only a single state. These results suggest how stable patterns of output are produced by some in vivo circuits and how command neurons from higher neural centers may control the activity of these circuits. The criteria that guided us in forming our circuits in culture were derived from theoretical studies on the properties of certain neuronal network models (e.g., Hopfield, J. J. 1984. Proc. Natl. Acad. Sci. USA. 81:3088-3092). Our results show that circuits consisting of only two co-cultured neurons can exhibit bistable output states of the form hypothesized to occur in populations of neurons. Images FIGURE 3 PMID:2344460

  7. Nanostimulation: manipulation of single neuron activity by juxtacellular current injection.

    PubMed

    Houweling, Arthur R; Doron, Guy; Voigt, Birgit C; Herfst, Lucas J; Brecht, Michael

    2010-03-01

    In the mammalian brain, many thousands of single-neuron recording studies have been performed but less than 10 single-cell stimulation studies. This paucity of single-cell stimulation data reflects a lack of easily applicable single-cell stimulation techniques. We provide a detailed description of the procedures involved in nanostimulation, a single-cell stimulation method derived from the juxtacellular labeling technique. Nanostimulation is easy to apply and can be directed to a wide variety of identifiable neurons in anesthetized and awake animals. We describe the recording approach and the parameters of the electric configuration underlying nanostimulation. We use glass pipettes with a DC resistance of 4-7 Mohms. Obtaining the juxtacellular configuration requires a close contact between pipette tip and neuron and is associated with a several-fold increase in resistance to values > or = 20 Mohms. The recorded action potential (AP) amplitude grows to > or = 2 mV, and neurons can be activated with currents in the nanoampere range--hence the term nanostimulation. While exact AP timing has not been achieved, AP frequency and AP number can be parametrically controlled. We demonstrate that nanostimulation can also be used to selectively inhibit sensory responses in identifiable neurons. Nanostimulation is biophysically similar to electroporation, and based on this assumption, we argue that nanostimulation operates on membranes in the micrometer area directly below the pipette tip, where membrane pores are induced by high transmembrane voltage. There is strong evidence to suggest that nanostimulation selectively activates single neurons and that the evoked effects are cell-specific. Nanostimulation therefore holds great potential for elucidating how single neurons contribute to behavior.

  8. Space Industrialization: Manufacturing and Construction Activities. Part 2.

    ERIC Educational Resources Information Center

    Story, Charles H.

    1983-01-01

    Discusses how space industrialization will provide direct benefits for our nation and will transfer technology to the many diverse areas of human activity. Examples are the development of the Space Shuttle, the Space Studies Institute, and the LS Society (advocates for colonizing space). (NRJ)

  9. Space Industrialization: Manufacturing and Construction Activities. Part 2.

    ERIC Educational Resources Information Center

    Story, Charles H.

    1983-01-01

    Discusses how space industrialization will provide direct benefits for our nation and will transfer technology to the many diverse areas of human activity. Examples are the development of the Space Shuttle, the Space Studies Institute, and the LS Society (advocates for colonizing space). (NRJ)

  10. Blog Construction as an Effective Tool in Biochemistry Active Learning

    ERIC Educational Resources Information Center

    Cubas Rolim, Estêvão; Martins de Oliveira, Julia; Dalvi, Luana T.; Moreira, Daniel C.; Garcia Caldas, Natasha; Fernandes Lobo, Felipe; André Polli, Démerson; Campos, Élida G.; Hermes-Lima, Marcelo

    2017-01-01

    To boost active learning in undergraduate students, they were given the task of preparing blogs on topics of clinical biochemistry. This "experiment" lasted for 12 teaching-semesters (from 2008 to 2013), and included a survey on the blogs' usefulness at the end of each semester. The survey (applied in the 2008-2010 period) used a…

  11. Blog construction as an effective tool in biochemistry active learning.

    PubMed

    Cubas Rolim, Estêvão; Martins de Oliveira, Julia; Dalvi, Luana T; Moreira, Daniel C; Garcia Caldas, Natasha; Fernandes Lobo, Felipe; André Polli, Démerson; Campos, Élida G; Hermes-Lima, Marcelo

    2017-05-01

    To boost active learning in undergraduate students, they were given the task of preparing blogs on topics of clinical biochemistry. This "experiment" lasted for 12 teaching-semesters (from 2008 to 2013), and included a survey on the blogs' usefulness at the end of each semester. The survey (applied in the 2008-2010 period) used a Likert-like questionnaire with eight questions and a 1-to-6 scale, from "totally disagree" to "fully agree." Answers of 428 students were analyzed and indicated overall approval of the blog activity: 86% and 35% of the responses scored 4-to-6 and 6, respectively. Considering the survey results, the high grades obtained by students on their blogs (averaging 8.3 in 2008-2010), and the significant increase in average grades of the clinical biochemistry exam after the beginning of the blog system (from 5.5 in 2007 to 6.4 in 2008-2010), we concluded that blogging activity on biochemistry is a promising tool for boosting active learning. © 2016 by The International Union of Biochemistry and Molecular Biology, 45(3):205-215, 2017. © 2016 The International Union of Biochemistry and Molecular Biology.

  12. Terrestrial Reference Systems and Frames. A review of current activities

    NASA Astrophysics Data System (ADS)

    Boucher, C. C.

    2009-12-01

    Terrestrial Reference Systems (TRS) refer to an important domain of Geodesy, involving both theoretical and applied aspects, as well as deep connections with Astronomy, Earth Sciences and Geo-information. The concept of TRS implies several visions : - An astronomical vision, using TRS to study translational and rotational motion of the Earth in inertial space - An Earth Science vision, using TRS to build physical models of the Earth system, and its various components (solid earth, oceans, atmosphere, hydrosphere) - A metrological vision, using TRS together with suitable coordinate systems (geographical coordinates, map projections…) to define geographical position of objects in the Earth’s vicinity A survey of current activities in this area is presented, referring to works done by the International Association of Geodesy (IAG) and more specifically its Commission 1, GGOS and IERS. A focus is done on concepts and terminology, as well as progresses to get a wide acceptance on the International Terrestrial Reference System (ITRS) and its system of realizations through global, regional and national frames, as well as through specific systems such as satellite navigation systems.

  13. 25 CFR 1000.246 - Must an AFA that contains a construction project or activity incorporate provisions of Federal...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 2 2014-04-01 2014-04-01 false Must an AFA that contains a construction project or activity incorporate provisions of Federal construction standards? 1000.246 Section 1000.246 Indians OFFICE... Construction § 1000.246 Must an AFA that contains a construction project or activity incorporate provisions...

  14. 25 CFR 1000.246 - Must an AFA that contains a construction project or activity incorporate provisions of Federal...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Must an AFA that contains a construction project or activity incorporate provisions of Federal construction standards? 1000.246 Section 1000.246 Indians OFFICE... Construction § 1000.246 Must an AFA that contains a construction project or activity incorporate provisions...

  15. 25 CFR 1000.246 - Must an AFA that contains a construction project or activity incorporate provisions of Federal...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 2 2012-04-01 2012-04-01 false Must an AFA that contains a construction project or activity incorporate provisions of Federal construction standards? 1000.246 Section 1000.246 Indians OFFICE... Construction § 1000.246 Must an AFA that contains a construction project or activity incorporate provisions...

  16. 25 CFR 1000.246 - Must an AFA that contains a construction project or activity incorporate provisions of Federal...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false Must an AFA that contains a construction project or activity incorporate provisions of Federal construction standards? 1000.246 Section 1000.246 Indians OFFICE... Construction § 1000.246 Must an AFA that contains a construction project or activity incorporate provisions...

  17. 25 CFR 1000.246 - Must an AFA that contains a construction project or activity incorporate provisions of Federal...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Must an AFA that contains a construction project or activity incorporate provisions of Federal construction standards? 1000.246 Section 1000.246 Indians OFFICE... Construction § 1000.246 Must an AFA that contains a construction project or activity incorporate provisions...

  18. A single-nanoparticle NO2 gas sensor constructed using active molecular plasmonics.

    PubMed

    Chen, Lichan; Wu, Bo; Guo, Longhua; Tey, Ruiwen; Huang, Youju; Kim, Dong-Hwan

    2015-01-25

    A single-nanoparticle plasmonic sensor for the sensitive detection of gas molecules (NO2) has been constructed. Taking advantage of active molecular plasmonics, the analyte selectively triggers a measurable spectral shift of ferrocene-modified single gold nanorods.

  19. An overview of EU and USA intestinal transplant current activity.

    PubMed

    Lauro, A; Panaro, F; Iyer, K R

    2017-04-01

    To report the current activity of intestinal transplantation in Europe (EU) and Unites States of America (USA), underlining outcomes in the last 5 years and discussing possible trends. Data review of results was performed through analysis of ITR and UNOS registries, Eurotransplant and newsletter transplant reports, congress abstracts, international published literature, personal communications and hospital web sites. The absence in Europe of a sole organization collecting donors and the presence of many low-volume centers (less than 5 cases/year) makes the difference with USA: in the last 5 years (2010-2014), 222 intestinal/multivisceral transplants have been performed in EU countries (most of them in the UK), while in USA, the number of transplants achieved 634 procedures in the same period of time. Waiting list mortality remains unacceptable in both continents. Improved short-term results, with over 80% survival at 1 year, have been achieved in the busiest transplant centers likely due to immune-induction agents, more recently to innovative cross match strategies and optimizing organ allocation, but long term outcomes are still inferior to other organ transplants. Most long-term survivors were reintegrated to society with self-sustained socioeconomic status. The economic burden for the society is high and related costs are different between USA and EU (and inside Europe between member state's health-care systems), but cost-effectiveness for intestinal transplantation still needs to be proved. Overall intestinal transplantation continues to develop in EU and USA together with surgical and medical rehabilitation of patients affected by short gut syndrome. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  20. Current radar responsive tag development activities at Sandia National Laboratories.

    SciTech Connect

    Plummer, Kenneth W.; Ormesher, Richard C.

    2003-09-01

    Over the past ten years, Sandia has developed RF radar responsive tag systems and supporting technologies for various government agencies and industry partners. RF tags can function as RF transmitters or radar transponders that enable tagging, tracking, and location determination functions. Expertise in tag architecture, microwave and radar design, signal analysis and processing techniques, digital design, modeling and simulation, and testing have been directly applicable to these tag programs. In general, the radar responsive tag designs have emphasized low power, small package size, and the ability to be detected by the radar at long ranges. Recently, there has been an interest in using radar responsive tags for Blue Force tracking and Combat ID (CID). The main reason for this interest is to allow airborne surveillance radars to easily distinguish U.S. assets from those of opposing forces. A Blue Force tracking capability would add materially to situational awareness. Combat ID is also an issue, as evidenced by the fact that approximately one-quarter of all U.S. casualties in the Gulf War took the form of ground troops killed by friendly fire. Because the evolution of warfare in the intervening decade has made asymmetric warfare the norm rather than the exception, swarming engagements in which U.S. forces will be freely intermixed with opposing forces is a situation that must be anticipated. Increasing utilization of precision munitions can be expected to drive fires progressively closer to engaged allied troops at times when visual de-confliction is not an option. In view of these trends, it becomes increasingly important that U.S. ground forces have a widely proliferated all-weather radar responsive tag that communicates to all-weather surveillance. The purpose of this paper is to provide an overview of the recent, current, and future radar responsive research and development activities at Sandia National Laboratories that support both the Blue Force Tracking

  1. Undergraduate student construction and interpretation of graphs in physics lab activities

    NASA Astrophysics Data System (ADS)

    Nixon, Ryan S.; Godfrey, T. J.; Mayhew, Nicholas T.; Wiegert, Craig C.

    2016-06-01

    Lab activities are an important element of an undergraduate physics course. In these lab activities, students construct and interpret graphs in order to connect the procedures of the lab with an understanding of the related physics concepts. This study investigated undergraduate students' construction and interpretation of graphs with best-fit lines in the context of two physics lab activities. Students' graphs were evaluated for overall graph quality and for the quality of the best-fit line. The strategies students used and their understanding of the meaning of the graph were accessed through interviews. The results suggest that undergraduate introductory physics students can successfully construct graphs with best-fit lines while not connecting the meaning of the graph to the underlying physics concepts. Furthermore, results indicated that the most challenging aspect of constructing a graph is setting up the scale, and that graphing is situated in specific contexts.

  2. Supramolecular coordination and antimicrobial activities of constructed mixed ligand complexes

    NASA Astrophysics Data System (ADS)

    El-Sonbati, A. Z.; Diab, M. A.; El-Bindary, A. A.; Abou-Dobara, M. I.; Seyam, H. A.

    2013-03-01

    A novel series of copper(II) and palladium(II) with 4-derivatives benzaldehyde pyrazolone (Ln) were synthesized. The mixed ligand complexes were prepared by using 1,10-phenanthroline (Phen) as second ligand. The structure of these complexes was identified and confirm by elemental analysis, molar conductivity, UV-Vis, IR and 1H NMR spectroscopy and magnetic moment measurements as well as thermal analysis. The ligand behaves as a neutral bidentate ligand through ON donor sites. ESR spectra show the simultaneous presence of a planar trans and a nearly planar cis isomers in the 1:2 ratio for all N,O complexes [Cu(Ln)2]Cl2ṡ2H2O. Schiff bases (Ln) were tested against bacterial species; namely two Gram positive bacteria (Staphylococcus aureus and Bacillus cereus) and two Gram negative bacteria (Escherichia coli and Klebsiella pneumoniae) and fungal species (Aspergillus niger, Fusarium oxysporium, Penicillium italicum and Alternaria alternata). The tested compounds have antibacterial activity against S. aureus, B. cereus and K. pneumoniae.

  3. Evaluation of the anti-tuberculosis activity generated by different multigene DNA vaccine constructs.

    PubMed

    Sali, Michela; Clarizio, Sandra; Pusceddu, Cinzia; Zumbo, Antonella; Pecorini, Giovanni; Rocca, Stefano; Zanetti, Stefania; Delogu, Giovanni; Fadda, Giovanni

    2008-05-01

    Development of multigenic constructs expressing Mycobacterium tuberculosis (Mtb) antigens may be a strategy to obtain improved DNA vaccines against tuberculosis (TB). Several multigenic constructs expressing two or three Mtb antigens as fusion proteins were developed, both as tPA- and ubiquitin-fusion proteins. To demonstrate proper protein expression and intracellular turnover all multiantigens were tagged with the HA epitope and constructs were used to transfect rhabdomyosarcoma (RD) cells. Antigen expression was demonstrated by immunofluorescence using anti-HA antibodies. C57Bl/6 mice were immunized with selected constructs and protective activity was assessed following aerogenic challenge with Mtb. Several of these constructs induced a significant level of protection in the lung and in the spleen. Immunization with the construct expressing tPA85B-ES6 induced a level of protection that approached that provided by BCG. Immunization with a combination of these constructs induced levels of protection that were not superior to those elicited by a single combination, and immunization with a construct expressing five Mtb antigens could not provide an improved level of protection compared to tPA85B-ES6. We conclude that the activity of a DNA vaccine based on tPA85B-ES6 cannot be enhanced by broadening the antigen repertoire with other highly immunogenic secreted Mtb proteins.

  4. Indicators of biofilm development and activity in constructed wetlands microcosms.

    PubMed

    Ragusa, S R; McNevin, D; Qasem, S; Mitchell, C

    2004-07-01

    Methods to measure protein, exopolysaccharide, viable cell number and INT reduction activity were tested on biofilm growing in a wastewater batch reactor. They were shown to be meaningful indicators of biofilm growth and correlated well with each other. Protein, exopolysaccharide, viable cells and INT reduction rates increased linearly over time. Viable cell number exhibited strong linear correlations with protein (R2= 0.98) and exopolysaccharide (R2= 0.99) while INT reduction rate was somewhat less well correlated (R2= 0.90). Our results indicate production rates of 0.91 x 10(-7) microg EPS per viable cell and 1.0 x 10(-7) microg protein per viable cell. Protein and polysaccharide specific INT reduction rates decreased by approximately 50%, whereas viable cell specific INT reduction rates decreased by 65% and the protein to polysaccharide ratio stayed relatively constant at between 1.1 and 1.2 as the biofilm developed. Measurement of protein, polysaccharide, viable cells and INT reduction rate at depth within the bioreactor showed that they were concentrated in the top 1cm of the influent end of the reactor and each decreased to a base level within 4.5 cm of the inlet. Protein to polysaccharide ratios increased with depth in the reactor and the specific INT reduction rates were maximal at 4.5 cm depth. The results indicate that the biomass can take upwards of 100 days to stabilize during batch (fill and draw) operation of subsurface wetlands and that the relative ratios of biomass components remain relatively constant during biofilm growth. Also, it appears that filtration of suspended solids results in biomass concentration at the inlet to the wetland.

  5. Cortical hyperpolarization-activated depolarizing current takes part in the generation of focal paroxysmal activities

    PubMed Central

    Timofeev, Igor; Bazhenov, Maxim; Sejnowski, Terrence; Steriade, Mircea

    2002-01-01

    During paroxysmal neocortical oscillations, sudden depolarization leading to the next cycle occurs when the majority of cortical neurons are hyperpolarized. Both the Ca2+-dependent K+ currents (IK(Ca)) and disfacilitation play critical roles in the generation of hyperpolarizing potentials. In vivo experiments and computational models are used here to investigate whether the hyperpolarization-activated depolarizing current (Ih) in cortical neurons also contributes to the generation of paroxysmal onsets. Hyperpolarizing current pulses revealed a depolarizing sag in ≈20% of cortical neurons. Intracellular recordings from glial cells indirectly indicated an increase in extracellular potassium concentration ([K+]o) during paroxysmal activities, leading to a positive shift in the reversal potential of K+-mediated currents, including Ih. In the paroxysmal neocortex, ≈20% of neurons show repolarizing potentials originating from hyperpolarizations associated with depth-electroencephalogram positive waves of spike-wave complexes. The onset of these repolarizing potentials corresponds to maximal [K+]o as estimated from dual simultaneous impalements from neurons and glial cells. Computational models showed how, after the increased [K+]o, the interplay between Ih, IK(Ca), and a persistent Na+ current, INa(P), could organize paroxysmal oscillations at a frequency of 2–3 Hz. PMID:12089324

  6. Remote sub-wavelength focusing of ultrasonically activated Lorentz current

    NASA Astrophysics Data System (ADS)

    Rekhi, Angad S.; Arbabian, Amin

    2017-04-01

    We propose the use of a combination of ultrasonic and magnetic fields in conductive media for the creation of RF electrical current via the Lorentz force, in order to achieve current generation with extreme sub-wavelength resolution at large depth. We demonstrate the modeling, generation, and measurement of Lorentz current in a conductive solution and show that this current can be localized at a distance of 13 cm from the ultrasonic source to a region about three orders of magnitude smaller than the corresponding wavelength of electromagnetic waves at the same operation frequency. Our results exhibit greater depth, tighter localization, and closer agreement with prediction than previous work on the measurement of Lorentz current in a solution of homogeneous conductivity. The proposed method of RF current excitation overcomes the trade-off between focusing and propagation that is fundamental in the use of RF electromagnetic excitation alone and has the potential to improve localization and depth of operation for RF current-based biomedical applications.

  7. Microbial fuel cell cathodes with poly(dimethylsiloxane) diffusion layers constructed around stainless steel mesh current collectors.

    PubMed

    Zhang, Fang; Saito, Tomonori; Cheng, Shaoan; Hickner, Michael A; Logan, Bruce E

    2010-02-15

    A new and simplified approach for making cathodes for microbial fuel cells (MFCs) was developed by using metal mesh current collectors and inexpensive polymer/carbon diffusion layers (DLs). Rather than adding a current collector to a cathode material such as carbon cloth, we constructed the cathode around the metal mesh itself, thereby avoiding the need for the carbon cloth or other supporting material. A base layer of poly(dimethylsiloxane) (PDMS) and carbon black was applied to the air-side of a stainless steel mesh, and Pt on carbon black with Nafion binder was applied to the solution-side as catalyst for oxygen reduction. The PDMS prevented water leakage and functioned as a DL by limiting oxygen transfer through the cathode and improving coulombic efficiency. PDMS is hydrophobic, stable, and less expensive than other DL materials, such as PTFE, that are commonly applied to air cathodes. Multiple PDMS/carbon layers were applied in order to optimize the performance of the cathode. Two PDMS/carbon layers achieved the highest maximum power density of 1610 +/- 56 mW/m(2) (normalized to cathode projected surface area; 47.0 +/- 1.6 W/m(3) based on liquid volume). This power output was comparable to the best result of 1635 +/- 62 mW/m(2) obtained using carbon cloth with three PDMS/carbon layers and a Pt catalyst. The coulombic efficiency of the mesh cathodes reached more than 80%, and was much higher than the maximum of 57% obtained with carbon cloth. These findings demonstrate that cathodes can be constructed around metal mesh materials such as stainless steel, and that an inexpensive coating of PDMS can prevent water leakage and lead to improved coulombic efficiencies.

  8. Safety risk assessment for vertical concrete formwork activities in civil engineering construction.

    PubMed

    López-Arquillos, Antonio; Rubio-Romero, Juan Carlos; Gibb, Alistair G F; Gambatese, John A

    2014-01-01

    The construction sector has one of the worst occupational health and safety records in Europe. Of all construction tasks, formwork activities are associated with a high frequency of accidents and injuries. This paper presents an investigation of the activities and related safety risks present in vertical formwork for in-situ concrete construction in the civil engineering sector. Using the methodology of staticized groups, twelve activities and ten safety risks were identified and validated by experts. Every safety risk identified in this manner was quantified for each activity using binary methodology according to the frequency and severity scales developed in prior research. A panel of experts was selected according to the relevant literature on staticized groups. The results obtained show that the activities with the highest risk in vertical formwork tasks are: Plumbing and leveling of forms, cutting of material, handling materials with cranes, and climbing or descending ladders. The most dangerous health and safety risks detected were falls from height, cutting and overexertion. The research findings provide construction practitioners with further evidence of the hazardous activities associated with concrete formwork construction and a starting point for targeting worker health and safety programmes.

  9. Current Management Strategy for Active Surveillance in Prostate Cancer.

    PubMed

    Syed, Jamil S; Javier-Desloges, Juan; Tatzel, Stephanie; Bhagat, Ansh; Nguyen, Kevin A; Hwang, Kevin; Kim, Sarah; Sprenkle, Preston C

    2017-02-01

    Active surveillance has been increasingly utilized as a strategy for the management of favorable-risk, localized prostate cancer. In this review, we describe contemporary management strategies of active surveillance, with a focus on traditional stratification schemes, new prognostic tools, and patient outcomes. Patient selection, follow-up strategy, and indication for delayed intervention for active surveillance remain centered around PSA, digital rectal exam, and biopsy findings. Novel tools which include imaging, biomarkers, and genetic assays have been investigated as potential prognostic adjuncts; however, their role in active surveillance remains institutionally dependent. Although 30-50% of patients on active surveillance ultimately undergo delayed treatment, the vast majority will remain free of metastasis with a low risk of dying from prostate cancer. The optimal method for patient selection into active surveillance is unknown; however, cancer-specific mortality rates remain excellent. New prognostication tools are promising, and long-term prospective, randomized data regarding their use in active surveillance will be beneficial.

  10. EVOLUTION OF RELATIVE MAGNETIC HELICITY AND CURRENT HELICITY IN NOAA ACTIVE REGION 11158

    SciTech Connect

    Jing, Ju; Liu, Chang; Lee, Jeongwoo; Xu, Yan; Deng, Na; Wang, Haimin; Park, Sung-Hong; Wiegelmann, Thomas E-mail: chang.liu@njit.edu E-mail: na.deng@njit.edu E-mail: freemler@kasi.re.kr E-mail: wiegelmann@linmpi.mpg.de

    2012-06-10

    Both magnetic and current helicities are crucial ingredients for describing the complexity of active-region magnetic structure. In this Letter, we present the temporal evolution of these helicities contained in NOAA active region 11158 during five days from 2011 February 12 to 16. The photospheric vector magnetograms of the Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory were used as the boundary conditions for the coronal field extrapolation under the assumption of nonlinear force-free field, from which we calculated both relative magnetic helicity and current helicity. We construct a time-altitude diagram in which altitude distribution of the magnitude of current helicity density is displayed as a function of time. This diagram clearly shows a pattern of upwardly propagating current helicity density over two days prior to the X2.2 flare on February 15 with an average propagation speed of {approx}36 m s{sup -1}. The propagation is synchronous with the emergence of magnetic flux into the photosphere, and indicative of a gradual energy buildup for the X2.2 flare. The time profile of the relative magnetic helicity shows a monotonically increasing trend most of the time, but a pattern of increasing and decreasing magnetic helicity above the monotonic variation appears prior to each of two major flares, M6.6 and X2.2, respectively. The physics underlying this bump pattern is not fully understood. However, the fact that this pattern is apparent in the magnetic helicity evolution but not in the magnetic flux evolution makes it a useful indicator in forecasting major flares.

  11. Body satisfaction is associated with Transtheoretical Model constructs for physical activity behavior change.

    PubMed

    Johnson, Paige; Fallon, Elizabeth A; Harris, Brandonn S; Burton, Bryce

    2013-03-01

    Despite advancements in health behavior theory and practice, less than half of the United States population meets physical activity recommendations. Two cross-sectional studies (n=432; n=1455) were conducted to explore associations between body satisfaction and Transtheoretical Model (TTM) constructs proposed to explain the physical activity behavior change process. A series of regression analyses were conducted, controlling for demographic and TTM variables, as appropriate. Results indicate that body satisfaction significantly explains 2-8% of variance in the TTM constructs responsible for promoting stage movement. Furthermore, body satisfaction was significantly associated with stages of change representing short (>6 months) and long-term (>5 years) maintenance of physical activity. Future research should continue to examine these construct relationships using more rigorous research designs, with the ultimate goal of implementing body satisfaction components alongside traditionally effective TTM interventions to improve physical activity maintenance.

  12. Extending the Constructs of Active Learning: Implications for Teachers' Pedagogy and Practice

    ERIC Educational Resources Information Center

    Drew, Valerie; Mackie, Lorele

    2011-01-01

    Active learning is a pedagogical construct widely appealed to within the global discourse of lifelong learning. However, an examination of the literature reveals a lack of clarity and consensus as to its meaning. This article provides a critical analysis of a range of dimensions underpinning the concept of active learning including policy…

  13. Active current gating in electrically biased conical nanopores

    NASA Astrophysics Data System (ADS)

    Bearden, Samuel; Simpanen, Erik; Zhang, Guigen

    2015-05-01

    We observed that the ionic current through a gold/silicon nitride (Si3N4) nanopore could be modulated and gated by electrically biasing the gold layer. Rather than employing chemical modification to alter device behavior, we achieved control of conductance directly by electrically biasing the gold portion of the nanopore. By stepping through a range of bias potentials under a constant trans-pore electric field, we observed a gating phenomenon in the trans-pore current response in a variety of solutions including potassium chloride (KCl), sodium chloride (NaCl), and potassium iodide (KI). A computational model with a conical nanopore was developed to examine the effect of the Gouy-Chapman-Stern electrical double layer along with nanopore geometry, work function potentials, and applied electrical bias on the ionic current. The numerical results indicated that the observed modulation and gating behavior was due to dynamic reorganization of the electrical double layer in response to changes in the electrical bias. Specifically, in the conducting state, the nanopore conductance (both numerical and experimental) is linearly proportional to the applied bias due to accumulation of charge in the diffuse layer. The gating effect occurs due to the asymmetric charge distribution in the fluid induced by the distribution of potentials at the nanopore surface. Time dependent changes in current due to restructuring of the electrical double layer occur when the electrostatic bias is instantaneously changed. The nanopore device demonstrates direct external control over nanopore behavior via modulation of the electrical double layer by electrostatic biasing.

  14. Re-Mediating Current Activity for the Future

    ERIC Educational Resources Information Center

    Gutierrez, Kris D.

    2012-01-01

    The growing poverty and inequity in America should create a sense of urgency in researchers to leverage what they know for the public good--to intervene more productively and vigorously in an ever more fragile public educational system and to address the increasing vulnerability of far too many youth in the United States. The current worldwide…

  15. A Laboratory Activity on the Eddy Current Brake

    ERIC Educational Resources Information Center

    Molina-Bolivar, J. A.; Abella-Palacios, A. J.

    2012-01-01

    The aim of this paper is to introduce a simple and low-cost experimental setup that can be used to study the eddy current brake, which considers the motion of a sliding magnet on an inclined conducting plane in terms of basic physical principles. We present a set of quantitative experiments performed to study the influence of the geometrical and…

  16. A National Perspective on the Current Evaluation Activities in Extension

    ERIC Educational Resources Information Center

    Lamm, Alexa J.; Israel, Glenn D.; Diehl, David

    2013-01-01

    In order to enhance Extension evaluation efforts it is important to understand current practices. The study reported here researched the evaluation behaviors of county-based Extension professionals. Extension professionals from eight states (n = 1,173) responded to a survey regarding their evaluation data collection, analysis, and reporting…

  17. A Laboratory Activity on the Eddy Current Brake

    ERIC Educational Resources Information Center

    Molina-Bolivar, J. A.; Abella-Palacios, A. J.

    2012-01-01

    The aim of this paper is to introduce a simple and low-cost experimental setup that can be used to study the eddy current brake, which considers the motion of a sliding magnet on an inclined conducting plane in terms of basic physical principles. We present a set of quantitative experiments performed to study the influence of the geometrical and…

  18. A National Perspective on the Current Evaluation Activities in Extension

    ERIC Educational Resources Information Center

    Lamm, Alexa J.; Israel, Glenn D.; Diehl, David

    2013-01-01

    In order to enhance Extension evaluation efforts it is important to understand current practices. The study reported here researched the evaluation behaviors of county-based Extension professionals. Extension professionals from eight states (n = 1,173) responded to a survey regarding their evaluation data collection, analysis, and reporting…

  19. Re-Mediating Current Activity for the Future

    ERIC Educational Resources Information Center

    Gutierrez, Kris D.

    2012-01-01

    The growing poverty and inequity in America should create a sense of urgency in researchers to leverage what they know for the public good--to intervene more productively and vigorously in an ever more fragile public educational system and to address the increasing vulnerability of far too many youth in the United States. The current worldwide…

  20. Shuttle Rocket Motor Program: NASA should delay awarding some construction contracts. Report to the Chair, Subcommittee on Government Activities and Transportation, Committee on Government Operations, House of Representatives

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Even though the executive branch has proposed terminating the Advanced Solid Rocket Motor (ASRM) program, NASA is proceeding with all construction activity planned for FY 1992 to avoid schedule slippage if the program is reinstated by Congress. However, NASA could delay some construction activities for at least a few months without affecting the current launch data schedule. For example, NASA could delay Yellow Creek's motor storage and dock projects, Stennis' dock project, and Kennedy's rotation processing and surge facility and dock projects. Starting all construction activities as originally planned could result in unnecessarily incurring additional costs and termination liability if the funding for FY 1993 is not provided. If Congress decides to continue the program, construction could still be completed in time to avoid schedule slippage.

  1. Shuttle Rocket Motor Program: NASA should delay awarding some construction contracts. Report to the Chair, Subcommittee on Government Activities and Transportation, Committee on Government Operations, House of Representatives

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Even though the executive branch has proposed terminating the Advanced Solid Rocket Motor (ASRM) program, NASA is proceeding with all construction activity planned for FY 1992 to avoid schedule slippage if the program is reinstated by Congress. However, NASA could delay some construction activities for at least a few months without affecting the current launch data schedule. For example, NASA could delay Yellow Creek's motor storage and dock projects, Stennis' dock project, and Kennedy's rotation processing and surge facility and dock projects. Starting all construction activities as originally planned could result in unnecessarily incurring additional costs and termination liability if the funding for FY 1993 is not provided. If Congress decides to continue the program, construction could still be completed in time to avoid schedule slippage.

  2. Get Current: Switch on Clean Energy Activity Book

    SciTech Connect

    2014-06-01

    Switching on clean energy technologies means strengthening the economy while protecting the environment. This activity book for all ages promotes energy awareness, with facts on different types of energy and a variety of puzzles in an energy theme.

  3. Construction of novel Saccharomyces cerevisiae strains for bioethanol active dry yeast (ADY) production.

    PubMed

    Zheng, Daoqiong; Zhang, Ke; Gao, Kehui; Liu, Zewei; Zhang, Xing; Li, Ou; Sun, Jianguo; Zhang, Xiaoyang; Du, Fengguang; Sun, Peiyong; Qu, Aimin; Wu, Xuechang

    2013-01-01

    The application of active dry yeast (ADY) in bioethanol production simplifies operation processes and reduces the risk of bacterial contamination. In the present study, we constructed a novel ADY strain with improved stress tolerance and ethanol fermentation performances under stressful conditions. The industrial Saccharomyces cerevisiae strain ZTW1 showed excellent properties and thus subjected to a modified whole-genome shuffling (WGS) process to improve its ethanol titer, proliferation capability, and multiple stress tolerance for ADY production. The best-performing mutant, Z3-86, was obtained after three rounds of WGS, producing 4.4% more ethanol and retaining 2.15-fold higher viability than ZTW1 after drying. Proteomics and physiological analyses indicated that the altered expression patterns of genes involved in protein metabolism, plasma membrane composition, trehalose metabolism, and oxidative responses contribute to the trait improvement of Z3-86. This work not only successfully developed a novel S. cerevisiae mutant for application in commercial bioethanol production, but also enriched the current understanding of how WGS improves the complex traits of microbes.

  4. Construction of Novel Saccharomyces cerevisiae Strains for Bioethanol Active Dry Yeast (ADY) Production

    PubMed Central

    Gao, Kehui; Liu, Zewei; Zhang, Xing; Li, Ou; Sun, Jianguo; Zhang, Xiaoyang; Du, Fengguang; Sun, Peiyong; Qu, Aimin; Wu, Xuechang

    2013-01-01

    The application of active dry yeast (ADY) in bioethanol production simplifies operation processes and reduces the risk of bacterial contamination. In the present study, we constructed a novel ADY strain with improved stress tolerance and ethanol fermentation performances under stressful conditions. The industrial Saccharomyces cerevisiae strain ZTW1 showed excellent properties and thus subjected to a modified whole-genome shuffling (WGS) process to improve its ethanol titer, proliferation capability, and multiple stress tolerance for ADY production. The best-performing mutant, Z3-86, was obtained after three rounds of WGS, producing 4.4% more ethanol and retaining 2.15-fold higher viability than ZTW1 after drying. Proteomics and physiological analyses indicated that the altered expression patterns of genes involved in protein metabolism, plasma membrane composition, trehalose metabolism, and oxidative responses contribute to the trait improvement of Z3-86. This work not only successfully developed a novel S. cerevisiae mutant for application in commercial bioethanol production, but also enriched the current understanding of how WGS improves the complex traits of microbes. PMID:24376860

  5. Ca2+ current and Ca(2+)-activated chloride current in isolated smooth muscle cells of the sheep urethra.

    PubMed Central

    Cotton, K D; Hollywood, M A; McHale, N G; Thornbury, K D

    1997-01-01

    1. Isolated sheep urethral cells were studied using the perforated patch clamp technique (T = 37 degrees C). Depolarizing steps ranging from -40 to -10 mV evoked an inward current that peaked within 10 ms and a slower inward current. Stepping back to the holding potential of -80 mV evoked large inward tail currents. All three currents were abolished by nifedipine (1 microM). Substitution of external Ca2+ with Ba2+ resulted in potentiation of the fast inward current and blockade of the slow current and tails. 2. Changing the chloride equilibrium potential (ECl) from 0 to +27 mV shifted the reversal potential of the tail currents from 1 +/- 1 to 27 +/- 1 mV (number of cells, n = 5). Chloride channel blockers, niflumic acid (10 microM) and anthracene-9-carboxylic acid (9AC, 1 mM), reduced the slow current and tails suggesting that these were Ca(2+)-activated Cl- currents, ICl(Ca). 4. Caffeine (10 mM) induced currents that reversed at ECl and were blocked by niflumic acid (10 microM). 5. In current clamp mode, some cells developed spontaneous transient depolarizations (STDs) and action potentials. Short exposure to nifedipine blocked the action potentials and unmasked STDs. In contrast, 9AC and niflumic acid reduced the amplitude of the STDs and blocked the action potentials. 6. In conclusion, these cells have both L-type ICa and ICl(Ca). The former appears to be responsible for the upstroke of the action potential, while the latter may act as a pacemaker current. PMID:9409476

  6. Teacher feedback during active learning: current practices in primary schools.

    PubMed

    van den Bergh, Linda; Ros, Anje; Beijaard, Douwe

    2013-06-01

    Feedback is one of the most powerful tools, which teachers can use to enhance student learning. It appears difficult for teachers to give qualitatively good feedback, especially during active learning. In this context, teachers should provide facilitative feedback that is focused on the development of meta-cognition and social learning. The purpose of the present study is to contribute to the existing knowledge about feedback and to give directions to improve teacher feedback in the context of active learning. The participants comprised 32 teachers who practiced active learning in the domain of environmental studies in the sixth, seventh, or eighth grade of 13 Dutch primary schools. A total of 1,465 teacher-student interactions were examined. Video observations were made of active learning lessons in the domain of environmental studies. A category system was developed based on the literature and empirical data. Teacher-student interactions were assessed using this system. Results. About half of the teacher-student interactions contained feedback. This feedback was usually focused on the tasks that were being performed by the students and on the ways in which these tasks were processed. Only 5% of the feedback was explicitly related to a learning goal. In their feedback, the teachers were directing (rather than facilitating) the learning processes. During active learning, feedback on meta-cognition and social learning is important. Feedback should be explicitly related to learning goals. In practice, these kinds of feedback appear to be scarce. Therefore, giving feedback during active learning seems to be an important topic for teachers' professional development. © 2012 The British Psychological Society.

  7. Comparison of adenosine triphosphate- and nicotine-activated inward currents in rat phaeochromocytoma cells.

    PubMed Central

    Nakazawa, K; Fujimori, K; Takanaka, A; Inoue, K

    1991-01-01

    1. The adenosine triphosphate (ATP)-activated inward current was compared to the nicotine-activated inward current in nerve growth factor (NGF)-treated rat phaeochromocytoma PC12 cells. 2. Both ATP and nicotine activated an inward current at negative holding potentials. The concentration of ATP necessary to activate the inward current was about 10-fold higher than that of nicotine; the EC50 was 20.5 microM for ATP and 2.4 microM for nicotine. The maximal responses induced by ATP and nicotine were almost identical in the same cells. The current-voltage relationship for the ATP-activated current was very similar to that for the nicotine-activated current, and both currents reversed around 0 mV in a physiological saline. 3. The ATP-activated current and the nicotine-activated current were not additive; the current activated by a combined administration of ATP (100 microM) and nicotine (10 microM) was only about 20% larger than the current activated by either ATP or nicotine alone. Nicotine (100 microM) did not increase the current activated by 1 microM-ATP. 4. ATP could activate an inward current in the cells even after desensitization to nicotine had developed. 5. Hexamethonium (100 microM) selectively blocked the nicotine-activated current whereas suramin (100 microM), a purinoceptor antagonist, selectively blocked the ATP-activated current. 6. Ionic selectivity was studied by changing compositions of extracellular solutions. When external Na+ was replaced with Cs+, both ATP and nicotine activated inward currents. However, with an extracellular solution containing Tris or glucosamine as a major cation, only ATP, not nicotine, activated an inward current. 7. ATP- and nicotine-activated currents were also recorded from cells bathed in a solution containing 1.8 mM-Ca2+ as the only external cation, suggesting that both pathways are Ca2+ permeable. 8. The results suggest that the ATP-sensitive ionic pathway is not independent of the nicotine-sensitive pathway in these

  8. Comparison of adenosine triphosphate- and nicotine-activated inward currents in rat phaeochromocytoma cells.

    PubMed

    Nakazawa, K; Fujimori, K; Takanaka, A; Inoue, K

    1991-03-01

    1. The adenosine triphosphate (ATP)-activated inward current was compared to the nicotine-activated inward current in nerve growth factor (NGF)-treated rat phaeochromocytoma PC12 cells. 2. Both ATP and nicotine activated an inward current at negative holding potentials. The concentration of ATP necessary to activate the inward current was about 10-fold higher than that of nicotine; the EC50 was 20.5 microM for ATP and 2.4 microM for nicotine. The maximal responses induced by ATP and nicotine were almost identical in the same cells. The current-voltage relationship for the ATP-activated current was very similar to that for the nicotine-activated current, and both currents reversed around 0 mV in a physiological saline. 3. The ATP-activated current and the nicotine-activated current were not additive; the current activated by a combined administration of ATP (100 microM) and nicotine (10 microM) was only about 20% larger than the current activated by either ATP or nicotine alone. Nicotine (100 microM) did not increase the current activated by 1 microM-ATP. 4. ATP could activate an inward current in the cells even after desensitization to nicotine had developed. 5. Hexamethonium (100 microM) selectively blocked the nicotine-activated current whereas suramin (100 microM), a purinoceptor antagonist, selectively blocked the ATP-activated current. 6. Ionic selectivity was studied by changing compositions of extracellular solutions. When external Na+ was replaced with Cs+, both ATP and nicotine activated inward currents. However, with an extracellular solution containing Tris or glucosamine as a major cation, only ATP, not nicotine, activated an inward current. 7. ATP- and nicotine-activated currents were also recorded from cells bathed in a solution containing 1.8 mM-Ca2+ as the only external cation, suggesting that both pathways are Ca2+ permeable. 8. The results suggest that the ATP-sensitive ionic pathway is not independent of the nicotine-sensitive pathway in these

  9. Icing Branch Current Research Activities in Icing Physics

    NASA Technical Reports Server (NTRS)

    Vargas, Mario

    2009-01-01

    Current development: A grid block transformation scheme which allows the input of grids in arbitrary reference frames, the use of mirror planes, and grids with relative velocities has been developed. A simple ice crystal and sand particle bouncing scheme has been included. Added an SLD splashing model based on that developed by William Wright for the LEWICE 3.2.2 software. A new area based collection efficiency algorithm will be incorporated which calculates trajectories from inflow block boundaries to outflow block boundaries. This method will be used for calculating and passing collection efficiency data between blade rows for turbo-machinery calculations.

  10. Teacher Feedback during Active Learning: Current Practices in Primary Schools

    ERIC Educational Resources Information Center

    van den Bergh, Linda; Ros, Anje; Beijaard, Douwe

    2013-01-01

    Background: Feedback is one of the most powerful tools, which teachers can use to enhance student learning. It appears dif?cult for teachers to give qualitatively good feedback, especially during active learning. In this context, teachers should provide facilitative feedback that is focused on the development of meta-cognition and social learning.…

  11. Teacher Feedback during Active Learning: Current Practices in Primary Schools

    ERIC Educational Resources Information Center

    van den Bergh, Linda; Ros, Anje; Beijaard, Douwe

    2013-01-01

    Background: Feedback is one of the most powerful tools, which teachers can use to enhance student learning. It appears dif?cult for teachers to give qualitatively good feedback, especially during active learning. In this context, teachers should provide facilitative feedback that is focused on the development of meta-cognition and social learning.…

  12. ASSESSING AND MANAGING MERCURY FROM HISTORIC AND CURRENT MINING ACTIVITIES

    EPA Science Inventory

    Mining activities in the US (not counting coal) produce between one and two billion tons of mine waste annually. Since many of the ore mines involve sulfide minerals, the production of acid mine drainage (AMD) is a common problem from these abandoned mine sites. The combination o...

  13. ASSESSING AND MANAGING MERCURY FROM HISTORIC AND CURRENT MINING ACTIVITIES

    EPA Science Inventory

    Mining activities in the US (not counting coal) produce between one and two billion tons of mine waste annually. Since many of the ore mines involve sulfide minerals, the production of acid mine drainage (AMD) is a common problem from these abandoned mine sites. The combination o...

  14. Using Ecological Momentary Assessment to Evaluate Current Physical Activity

    PubMed Central

    Marszalek, Jolanta; Morgulec-Adamowicz, Natalia; Rutkowska, Izabela; Kosmol, Andrzej

    2014-01-01

    Objective. The purpose of this study was to assess the value of ecological momentary assessment in evaluating physical activity among children, adolescents, and adults. It also determines whether ecological momentary assessment fulfills the criteria of validity, reliability, objectivity, norms, and standardization applied to the tools used for the evaluation of physical activity. Methods. The EBSCO-CINHAL, Medline, PsycINFO, PubMed, and SPORTDiscuss databases were reviewed in December 2012 for articles associated with EMA. Results. Of the 20 articles examined, half (10) used electronic methods for data collection, although various methods were used, ranging from pen and paper to smartphone applications. Ten studies used objective monitoring equipment. Nineteen studies were performed over 4 days. While the validity of the EMA method was discussed in 18 studies, only four found it to be objective. In all cases, the EMA procedures were precisely documented and confirmed to be feasible. Conclusions. Ecological momentary assessment is a valid, reliable, and feasible approach to evaluate activity and sedentary behavior. Researchers should be aware that while ecological momentary assessment offers many benefits, it simultaneously imposes many limitations which should be considered when studying physical activity. PMID:25126580

  15. Calcium-activated conductance in skate electroreceptors: current clamp experiments.

    PubMed

    Clusin, W T; Bennett, M V

    1977-02-01

    When current clamped, skate electroreceptor epithelium produces large action potentials in response to stimuli that depolarize the lumenal faces of the receptor cells. With increasing stimulus strength these action potentials become prolonged. When the peak voltage exceeds about 140 mV the repolarizing phase is blocked until the end of the stimulus. Perfusion experiments show that the rising phase of the action potential results from an increase in calcium permeability in the lumenal membranes. Perfusion of the lumen with cobalt or with a zero calcium solution containing EGTA blocks the action potential. Perfusion of the lumen with a solution containing 10 mM Ca and 20 mM EGTA initially slows the repolarizing process at all voltages and lowers the potential at which it is blocked. With prolonged perfusion, repolarization is blocked at all voltages. When excitability is abolished by perfusion with cobalt, or with a zero calcium solution containing EGTA, no delayed rectification occurs. We suggest that repolarization during the action potential depends on an influx of calcium into the cytoplasm, and that the rate of repolarization depends on the magnitude of the inward calcium current. Increasingly large stimuli reduce the rate of repolarization by reducing the driving force for calcium, and then block repolarization by causing the lumenal membrane potential to exceed ECa. Changes in extracellular calcium affect repolarization in a manner consistent with the resulting change in ECa.

  16. Geothermal materials development: FY 1990 accomplishments and current activities

    SciTech Connect

    Kukacka, L.E.

    1991-01-01

    Advances in the development of hydrothermally stable materials, the commercial availabilities of which are considered essential for the attainment of the Geothermal Division's (GD) Hydrothermal Category Objectives, continue to be made. Fiscal year 1990 R D was focused on reducing well drilling and completion costs, energy conversion costs, and on mitigating corrosion in well casing. Activities on lost circulation control materials, CO{sub 2}-resistant lightweight cements and thermally conductive corrosion and scale-resistant linear systems have reached the final development stages. In addition, field tests to determine the feasibility for the use of polymer cement liners to mitigate HCl-induced corrosion at the Geysers were performed. Technology transfer efforts on high temperature elastomers for use in drilling tools such as drillpipe protectors and rotating head seals were continued under Geothermal Drilling Organization sponsorship. Recent accomplishments and ongoing work on each of these activities are described in the paper. 8 refs.

  17. Current status of pyrazole and its biological activities

    PubMed Central

    Naim, Mohd Javed; Alam, Ozair; Nawaz, Farah; Alam, Md. Jahangir; Alam, Perwaiz

    2016-01-01

    Pyrazole are potent medicinal scaffolds and exhibit a full spectrum of biological activities. This review throws light on the detailed synthetic approaches which have been applied for the synthesis of pyrazole. This has been followed by an in depth analysis of the pyrazole with respect to their medical significance. This follow-up may help the medicinal chemists to generate new leads possessing pyrazole nucleus with high efficacy. PMID:26957862

  18. Current status of pyrazole and its biological activities.

    PubMed

    Naim, Mohd Javed; Alam, Ozair; Nawaz, Farah; Alam, Md Jahangir; Alam, Perwaiz

    2016-01-01

    Pyrazole are potent medicinal scaffolds and exhibit a full spectrum of biological activities. This review throws light on the detailed synthetic approaches which have been applied for the synthesis of pyrazole. This has been followed by an in depth analysis of the pyrazole with respect to their medical significance. This follow-up may help the medicinal chemists to generate new leads possessing pyrazole nucleus with high efficacy.

  19. Current activities of the Yersinia effector protein YopM.

    PubMed

    Höfling, Sabrina; Grabowski, Benjamin; Norkowski, Stefanie; Schmidt, M Alexander; Rüter, Christian

    2015-05-01

    Yersinia outer protein M (YopM) belongs to the group of Yop effector proteins, which are highly conserved among pathogenic Yersinia species. During infection, the effectors are delivered into the host cell cytoplasm via the type 3 secretion system to subvert the host immune response and support the survival of Yersinia. In contrast to the other Yop effectors, YopM does not possess a known enzymatic activity and its molecular mechanism(s) of action remain(s) poorly understood. However, YopM was shown to promote colonization and dissemination of Yersinia, thus being crucial for the pathogen's virulence in vivo. Moreover, YopM interacts with several host cell proteins and might utilize them to execute its anti-inflammatory activities. The results obtained so far indicate that YopM is a multifunctional protein that counteracts the host immune defense by multiple activities, which are at least partially independent of each other. Finally, its functions seem to be also influenced by differences between the specific YopM isoforms expressed by Yersinia subspecies. In this review, we focus on the global as well as more specific contribution of YopM to virulence of Yersinia during infection and point out the various extra- and intracellular molecular functions of YopM. In addition, the novel cell-penetrating ability of recombinant YopM and its potential applications as a self-delivering immunomodulatory therapeutic will be discussed. Copyright © 2015 Elsevier GmbH. All rights reserved.

  20. Proton currents constrain structural models of voltage sensor activation

    PubMed Central

    Randolph, Aaron L; Mokrab, Younes; Bennett, Ashley L; Sansom, Mark SP; Ramsey, Ian Scott

    2016-01-01

    The Hv1 proton channel is evidently unique among voltage sensor domain proteins in mediating an intrinsic ‘aqueous’ H+ conductance (GAQ). Mutation of a highly conserved ‘gating charge’ residue in the S4 helix (R1H) confers a resting-state H+ ‘shuttle’ conductance (GSH) in VGCs and Ci VSP, and we now report that R1H is sufficient to reconstitute GSH in Hv1 without abrogating GAQ. Second-site mutations in S3 (D185A/H) and S4 (N4R) experimentally separate GSH and GAQ gating, which report thermodynamically distinct initial and final steps, respectively, in the Hv1 activation pathway. The effects of Hv1 mutations on GSH and GAQ are used to constrain the positions of key side chains in resting- and activated-state VS model structures, providing new insights into the structural basis of VS activation and H+ transfer mechanisms in Hv1. DOI: http://dx.doi.org/10.7554/eLife.18017.001 PMID:27572256

  1. A laboratory activity on the eddy current brake

    NASA Astrophysics Data System (ADS)

    Molina-Bolívar, J. A.; Abella-Palacios, A. J.

    2012-05-01

    The aim of this paper is to introduce a simple and low-cost experimental setup that can be used to study the eddy current brake, which considers the motion of a sliding magnet on an inclined conducting plane in terms of basic physical principles. We present a set of quantitative experiments performed to study the influence of the geometrical and electromagnetic properties of the magnet on the magnetic drag force. This video-based experiment is ideal for the study of kinematic graphs and the application of Newton's laws. Video motion analysis software enables students to make precise measurements of the magnet's position at incremental times during its motion, thus allowing them to quantify electromagnetic induction phenomena. The equipment needed for this experiment and data collection software are present in most physics teaching laboratories or are inexpensive and available.

  2. [Active teaching-learning methodologies in health education: current debates].

    PubMed

    Mitre, Sandra Minardi; Siqueira-Batista, Rodrigo; Girardi-de-Mendonça, José Márcio; de Morais-Pinto, Neila Maria; Meirelles, Cynthia de Almeida Brandão; Pinto-Porto, Cláudia; Moreira, Tânia; Hoffmann, Leandro Marcial Amaral

    2008-12-01

    The vertiginous transformations of the contemporary societies have been raising questions concerning aspects of professional education. Such questions have been raised in a more and more incisive way. This debate gains a new shape when applied to health work, where theory and practice cannot be dissociated, and where the development of an integral vision of the human being and the amplification of the concept care are essential for a proper performance. Based on these considerations, this article aims to discuss the main methodological transformations in the education process of health professionals, with emphasis to active teaching-learning methodologies.

  3. Attending to the Grammatical Errors of Students Using Constructive Teaching and Learning Activities

    ERIC Educational Resources Information Center

    Wornyo, Albert Agbesi

    2016-01-01

    This study was a classroom-based action research. In this study, constructive teaching and learning activities were used to help learners improve on their grammar and usage with a focus on how to help them internalize subject verb agreement rules. The purpose of the research was to assist learners to improve upon their performance in grammar and…

  4. Medical Student Stories of Participation in Patient Care-Related Activities: The Construction of Relational Identity

    ERIC Educational Resources Information Center

    Warmington, Sally; McColl, Geoffrey

    2017-01-01

    Professional identity formation is acknowledged as one of the fundamental tasks of contemporary medical education. Identity is a social phenomenon, constructed through participation in everyday activities and an integral part of every learning interaction. In this paper we report from an Australian ethnographic study into how medical students and…

  5. 78 FR 25958 - Takes of Marine Mammals Incidental to Specified Activities; Demolition and Construction...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-03

    ...NMFS has received an application from the City of San Diego for an Incidental Harassment Authorization (IHA) to take small numbers of marine mammals, by Level B harassment, incidental to demolition and construction activities of the Children's Pool Lifeguard Station in La Jolla, California. NMFS has reviewed the application, including all supporting documents, and determined that it is......

  6. Promoting Constructive Activities that Support Vicarious Learning during Computer-Based Instruction

    ERIC Educational Resources Information Center

    Gholson, Barry; Craig, Scotty D.

    2006-01-01

    This article explores several ways computer-based instruction can be designed to support constructive activities and promote deep-level comprehension during vicarious learning. Vicarious learning, discussed in the first section, refers to knowledge acquisition under conditions in which the learner is not the addressee and does not physically…

  7. Reliability and Construct Validity of Turkish Version of Physical Education Activities Scale

    ERIC Educational Resources Information Center

    Memis, Ugur Altay

    2013-01-01

    This research was conducted to examine the reliability and construct validity of Turkish version of physical education activities scale (PEAS) which was developed by Thomason (2008). Participants in this study included 313 secondary and high school students from 7th to 11th grades. To analyse the data, confirmatory factor analysis, post hoc…

  8. 78 FR 23910 - Taking of Marine Mammals Incidental to Specified Activities; Construction at Orcas Island and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-23

    ... Specified Activities; Construction at Orcas Island and Friday Harbor Ferry Terminals AGENCY: National Marine... at the Orcas Island and Friday Harbor ferry terminals in Washington State between September 2013 and... the Orcas Island and Friday Harbor ferry terminals in Washington State. On July 20, WSDOT submitted...

  9. Reliability and Construct Validity of Turkish Version of Physical Education Activities Scale

    ERIC Educational Resources Information Center

    Memis, Ugur Altay

    2013-01-01

    This research was conducted to examine the reliability and construct validity of Turkish version of physical education activities scale (PEAS) which was developed by Thomason (2008). Participants in this study included 313 secondary and high school students from 7th to 11th grades. To analyse the data, confirmatory factor analysis, post hoc…

  10. Medical Student Stories of Participation in Patient Care-Related Activities: The Construction of Relational Identity

    ERIC Educational Resources Information Center

    Warmington, Sally; McColl, Geoffrey

    2017-01-01

    Professional identity formation is acknowledged as one of the fundamental tasks of contemporary medical education. Identity is a social phenomenon, constructed through participation in everyday activities and an integral part of every learning interaction. In this paper we report from an Australian ethnographic study into how medical students and…

  11. T & I--Building Construction, Safety. Kit No. 1. Instructor's Manual [and] Student Learning Activity Guide.

    ERIC Educational Resources Information Center

    Howard, John

    An instructor's manual and student activity guide on building construction safety are provided in this set of prevocational education materials which focuses on the vocational area of trade and industry. (This set of materials is one of ninety-two prevocational education sets arranged around a cluster of seven vocational offerings: agriculture,…

  12. Recombinant host cells and nucleic acid constructs encoding polypeptides having cellulolytic enhancing activity

    DOEpatents

    Schnorr, Kirk; Kramer, Randall

    2017-03-28

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  13. Problem Solving Activity in the Workplace and the School: The Case of Constructing Solids.

    ERIC Educational Resources Information Center

    Jurdak, Murad; Shahin, Iman

    2001-01-01

    Documents, compares, and analyzes the nature of spatial reasoning by practitioners (plumbers) in the workplace and students in the school setting while constructing solids, with given specifications, from plane surfaces. Results confirm the power of activity theory and its methodology in explaining and identifying the structural differences…

  14. Constructive Play: Building Symbolic Competence through Physical Activity and Social Interaction.

    ERIC Educational Resources Information Center

    Fennel, Linda

    Whether physical activity and verbal communication would affect kindergarten students' scores on the Metropolitan Readiness Tests (MRT) was investigated. Twenty subjects were administered Level I of the MRT when they entered kindergarten. For 5 days per week for 4 weeks, the 10 subjects in the experimental group worked at constructive play tasks…

  15. International Space Environment Service: Current Activities and Future Plans

    NASA Astrophysics Data System (ADS)

    Boteler, D. H.; H. Lundstedt, H.; Kunches, J.; Coffey, H.; Hilgers, A.; Patterson, G.; van der Linden, R.; Lam, H.-L.; Wang, H.; Buresova, D.; et al.

    The International Space Environment Service ISES is a permanent service of the Federations of Astronomical and Geophysical Data Analysis Services FAGS with the mission to encourage and facilitate near-real-time international monitoring and prediction of the space environment This is done through the work of Regional Warning Centres RWC around the world who collaborate in the exploitation of a wide range of space-based and ground-based data Rapid exchange of information about the space environment is facilitated through the use of standard URSIgram codes RWCs also collaborate in sharing expertise in particular areas of specialty ISES also prepares the International Geophysical Calendar IGC each year giving a list of World Days during which scientists are encouraged to carry out their experiments and the monthly Spacewarn Bulletins which summarize the status of satellites in earth orbit and in the interplanetary medium ISES has its origins in the former URSI Central Committee of USRIgrams which initiated rapid international data interchange services in 1928 The modern system of regional warning centres was set up during the International Geophysical Year and now exist in every populated continent except Africa and South America ISES as part of its IGY 50 activities is working to develop RWCs in those continents ISES is also involved in developing new multi-national space weather services for example for trans-polar flights New space-based data on space weather activity will require extensive collaboration if it is to be

  16. Antimicrobial activity of carvacrol: current progress and future prospectives.

    PubMed

    Nostro, Antonia; Papalia, Teresa

    2012-04-01

    During the last few years the scientific community has shown a considerable interest in the study of plant materials as sources of new compounds to be processed into antimicrobial agents. In this context, carvacrol, a monoterpenic phenol, has emerged for its wide spectrum activity extended to food spoilage or pathogenic fungi, yeast and bacteria as well as human, animal and plant pathogenic microorganisms including drug-resistant and biofilm forming microorganisms. The antibacterial activity of carvacrol has been attributed to its considerable effects on the structural and functional properties of cytoplasmatic membrane. The data reported in this review provide an overview of the published literature regarding the antimicrobial properties of carvacrol and the recent patents claimed in order to highlight its future applications as a new antimicrobial agent. These could concern either the natural preservation in the cosmetic and food industries or an alternative which supports the conventional antimicrobial protocols. Interestingly, carvacrol alone or associated with one or more synergistic products could be incorporated in different formulations for biomedical and food packaging applications. However, more detailed safety investigations and in vivo studies should be carried out so that this molecule could be used in the future.

  17. Activation of Transient Receptor Potential Vanilloid 4 Increases NMDA-Activated Current in Hippocampal Pyramidal Neurons

    PubMed Central

    Li, Lin; Qu, Weijun; Zhou, Libin; Lu, Zihong; Jie, Pinghui; Chen, Lei; Chen, Ling

    2013-01-01

    The glutamate excitotoxicity, mediated through N-methyl-d-aspartate receptors (NMDARs), plays an important role in cerebral ischemia injury. Transient receptor potential vanilloid 4 (TRPV4) can be activated by multiple stimuli that may happen during stroke. The present study evaluated the effect of TRPV4 activation on NMDA-activated current (INMDA) and that of blocking TRPV4 on brain injury after focal cerebral ischemia in mice. We herein report that activation of TRPV4 by 4α-PDD and hypotonic stimulation increased INMDA in hippocampal CA1 pyramidal neurons, which was sensitive to TRPV4 antagonist HC-067047 and NMDAR antagonist AP-5, indicating that TRPV4 activation potentiates NMDAR response. In addition, the increase in INMDA by hypotonicity was sensitive to the antagonist of NMDAR NR2B subunit, but not of NR2A subunit. Furthermore, antagonists of calcium/calmodulin-dependent protein kinase II (CaMKII) significantly attenuated hypotonicity-induced increase in INMDA, while antagonists of protein kinase C or casein kinase II had no such effect, indicating that phosphorylation of NR2B subunit by CaMKII is responsible for TRPV4-potentiated NMDAR response. Finally, we found that intracerebroventricular injection of HC-067047 after 60 min middle cerebral artery occlusion reduced the cerebral infarction with at least a 12 h efficacious time-window. These findings indicate that activation of TRPV4 increases NMDAR function, which may facilitate glutamate excitotoxicity. Closing TRPV4 may exert potent neuroprotection against cerebral ischemia injury through many mechanisms at least including the prevention of NMDAR-mediated glutamate excitotoxicity. PMID:23459987

  18. Construction of a Fusion Enzyme Exhibiting Superoxide Dismutase and Peroxidase Activity.

    PubMed

    Sharapov, M G; Novoselov, V I; Ravin, V K

    2016-04-01

    A chimeric gene construct encoding human peroxiredoxin 6 and Mn-superoxide dismutase from Escherichia coli was developed. Conditions for expression of the fusion protein in E. coli cell were optimized. Fusing of the enzymes into a single polypeptide chain with peroxiredoxin 6 at the N-terminus (PSH) did not affect their activities. On the contrary, the chimeric protein with reverse order of enzymes (SPH) was not obtained in a water-soluble active form. The active chimeric protein (PSH) exhibiting both peroxidase and superoxide dismutase activities was prepared and its physicochemical properties were characterized.

  19. Effect of electric current frequency on the activation kinetics of raw charcoal

    SciTech Connect

    Shevchenko, A.O.; Ivakhnyuk, G.K.; Fedorov, N.F.

    1993-12-10

    The effect of electric current frequency on the kinetics of raw charcoal activation with water vapor has been investigated. It was established that under the effect of alternating current the rate constant increases under otherwise equal conditions. A dependence of the reaction rate on the current frequency was found. It was discovered that under the effect of alternating current the activation energy of interaction with water vapor diminishes.

  20. Estrogenic activity and steroid hormones in swine wastewater through a lagoon constructed-wetland system.

    PubMed

    Shappell, Nancy W; Billey, Lloyd O; Forbes, Dean; Matheny, Terry A; Poach, Matthew E; Reddy, Gudigopuram B; Hunt, Patrick G

    2007-01-15

    Anaerobic lagoons and treatment wetlands are used worldwide to treat wastewater from dense livestock production facilities; however, there is very limited data on the hormonal activity of the wastewater effluent produced by these treatment systems. The objectives of this experiment were to measure (1) the hormonal activity of the initial effluent and (2) the effectiveness of a lagoon-constructed wetland treatment system for producing an effluent with a low hormonal activity. Wastewater samples were taken in April, July, and November 2004 and July 2005 from a lagoon-constructed wetland system at a swine farrowing facility. Estrogenic activity (in vitro E-screen assay), 17 beta-estradiol (E2), and testosterone concentrations (LC/MS-MS) were measured. A high correlation was found between estradiol equivalents determined by E-screen and LC/MS-MS (R2 = 0.82). Nutrient removal was measured to ensure that the wetlands were functioning in a manner similar to literature reports. Nutrient removals were typical for treatment wetlands: TKN 59-75% and orthophosphate 0-18%. Wetlands decreased estrogenic activity by 83-93%. Estrone was the most persistent estrogenic compound. Constructed wetlands produced effluents with estrogenic activity below the lowest equivalent E2 concentration known to have an effect on fish (10 ng/L or approximately 37 x 10(-12) M).

  1. The PRISM data/model co-operative: current modelling activities, future plans and data requirements

    NASA Astrophysics Data System (ADS)

    Haywood, Alan

    2010-05-01

    Here we review current activities and future model and data requirements associated with the palaeoclimate modelling arm of the PRISM data/model co-operative. The talk will begin with a description of modelling focussed on understanding the behaviour of climate phenomena that are responsible for generating significant regional decadal and sub-decadal climate variability (ENSO and NAO), and the challenges associated with linking such predictions to mid-Piacenzian palaeoenvironmental data. Secondly, we will examine current efforts to understand the role of changing sea-surface temperatures, in relation to other important boundary conditions, in driving global and regional climate/environmental shifts recognised in the proxy data. Thirdly, we will examine initial results from coupled climate and ice sheet modelling examining the response of the Greenland and East Antarctic Ice Sheets to orbital variations and how these predicted changes relate to current estimates of mid-Piacenzian mean sea level and sea level variability. Our future plans centre on (a) the development of the Pliocene Model Intercomparison Project, (b) understanding uncertainty in climate model predictions of mid-Piacenzian climates and (c) moving towards an Earth System Modelling framework for the PRISM interval. With the 4th iteration of the PRISM palaeoenvironmental data set under construction we briefly outline how the demands of modern climate and earth system models will partly shape PRISM4, as well as the new scientific opportunities that will stem from it (e.g. the advent of isotope enabled models, higher resolution boundary conditions, river routing schemes and palaeobathymetry).

  2. The Current Case of Quinolones: Synthetic Approaches and Antibacterial Activity.

    PubMed

    Naeem, Abdul; Badshah, Syed Lal; Muska, Mairman; Ahmad, Nasir; Khan, Khalid

    2016-03-28

    Quinolones are broad-spectrum synthetic antibacterial drugs first obtained during the synthesis of chloroquine. Nalidixic acid, the prototype of quinolones, first became available for clinical consumption in 1962 and was used mainly for urinary tract infections caused by Escherichia coli and other pathogenic Gram-negative bacteria. Recently, significant work has been carried out to synthesize novel quinolone analogues with enhanced activity and potential usage for the treatment of different bacterial diseases. These novel analogues are made by substitution at different sites--the variation at the C-6 and C-8 positions gives more effective drugs. Substitution of a fluorine atom at the C-6 position produces fluroquinolones, which account for a large proportion of the quinolones in clinical use. Among others, substitution of piperazine or methylpiperazine, pyrrolidinyl and piperidinyl rings also yields effective analogues. A total of twenty six analogues are reported in this review. The targets of quinolones are two bacterial enzymes of the class II topoisomerase family, namely gyrase and topoisomerase IV. Quinolones increase the concentration of drug-enzyme-DNA cleavage complexes and convert them into cellular toxins; as a result they are bactericidal. High bioavailability, relative low toxicity and favorable pharmacokinetics have resulted in the clinical success of fluoroquinolones and quinolones. Due to these superior properties, quinolones have been extensively utilized and this increased usage has resulted in some quinolone-resistant bacterial strains. Bacteria become resistant to quinolones by three mechanisms: (1) mutation in the target site (gyrase and/or topoisomerase IV) of quinolones; (2) plasmid-mediated resistance; and (3) chromosome-mediated quinolone resistance. In plasmid-mediated resistance, the efflux of quinolones is increased along with a decrease in the interaction of the drug with gyrase (topoisomerase IV). In the case of chromosome

  3. Current Situation and Analysis of Geography Teachers' Active Learning Knowledge and Usage in Turkey

    ERIC Educational Resources Information Center

    Tuna, Fikret

    2012-01-01

    In parallel to the developments in the approach to education, the secondary education geography curriculum in Turkey was renewed in 2005. This new programme encourages the use of active learning methods and techniques in the classroom by adopting the idea that students should construct and interpret knowledge by actively participating in the…

  4. Current Situation and Analysis of Geography Teachers' Active Learning Knowledge and Usage in Turkey

    ERIC Educational Resources Information Center

    Tuna, Fikret

    2012-01-01

    In parallel to the developments in the approach to education, the secondary education geography curriculum in Turkey was renewed in 2005. This new programme encourages the use of active learning methods and techniques in the classroom by adopting the idea that students should construct and interpret knowledge by actively participating in the…

  5. The Self-Presentation Motives for Physical Activity Questionnaire: Instrument Development and Preliminary Construct Validity Evidence.

    PubMed

    Howle, Timothy C; Dimmock, James A; Whipp, Peter R; Jackson, Ben

    2015-06-01

    With the aim of advancing the literature on impression management in physical activity settings, we developed a theoretically derived 2 by 2 instrument that was designed to measure different types of context-specific self-presentation motives. Following item generation and expert review (Study 1), the instrument was completed by 206 group exercise class attendees (Study 2) and 463 high school physical education students (Study 3). Our analyses supported the intended factor structure (i.e., reflecting acquisitive-agentic, acquisitive-communal, protective-agentic, and protective-communal motives). We found some support for construct validity, and the self-presentation motives were associated with variables of theoretical and applied interest (e.g., impression motivation and construction, social anxiety, social and achievement goals, efficacy beliefs, engagement). Taken together, the results indicate that the Self-presentation Motives for Physical Activity Questionnaire (SMPAQ) may be useful for measuring various types of self-presentation motives in physical activity settings.

  6. Medical student stories of participation in patient care-related activities: the construction of relational identity.

    PubMed

    Warmington, Sally; McColl, Geoffrey

    2017-03-01

    Professional identity formation is acknowledged as one of the fundamental tasks of contemporary medical education. Identity is a social phenomenon, constructed through participation in everyday activities and an integral part of every learning interaction. In this paper we report from an Australian ethnographic study into how medical students and patients use narrative to construct their identities. The dialogic narrative analysis employed focused on the production of meaning through the use of language devices in a given context, and the juxtaposition of multiple perspectives. Two stories told by students about their participation in patient care-related activities reveal how identities are constructed in this context through depictions of the relationships between medical students, patients and clinical teachers. These students use the rhetorical functions of stories to characterise doctors and patients in certain ways, and position themselves in relation to them. They defend common practices that circumvent valid consent processes, justified by the imperative to maximise students' participation in patient care-related activities. In doing so, they identify patients as their adversaries, and doctors as allies. Both students are influenced by others' expectations but one reveals the active nature of identity work, describing subtle acts of resistance. These stories illustrate how practices for securing students' access to patients can influence students' emerging identities, with implications for their future disclosure and consent practices. We argue that more collaborative ways of involving medical students in patient care-related activities will be facilitated if students and clinical teachers develop insight into the relational nature of identity work.

  7. Voltage-activated currents recorded from rabbit pigmented ciliary body epithelial cells in culture.

    PubMed Central

    Fain, G L; Farahbakhsh, N A

    1989-01-01

    1. The whole-cell recording mode of the patch-clamp technique was used to investigate the presence of voltage-activated currents in the isolated pigmented cells from the rabbit ciliary body epithelium grown in culture. 2. In Ringer solution with composition similar to that of the rabbit aqueous humour, depolarizing voltage steps activated a transient inward current and a delayed outward current, while hyperpolarization elicited an inwardly rectified current. 3. The depolarization-activated inward current was mainly carried by Na+ and was blocked by submicromolar concentrations of tetrodotoxin. This current in many cells was sufficiently large to produce a regenerative Na+ spike. 4. The depolarization-activated outward current was carried by K+ and blocked by external TEA and Ba2+. Its activation appeared to be Ca2(+)-independent. 5. The hyperpolarization-activated inward current was almost exclusively carried by K+ and was blocked by Ba2+ and Cs+. For large hyperpolarizations below -120 mV, this current exhibited a biphasic activation with a fast transient peak followed by a slower sag, that appeared to be due to K+ depletion. 6. The voltage-dependent K+ conductances probably act to stabilize the cell membrane resting potential and may also play a role in ion transport. The function of the Na(+)-dependent inward current is unclear, but it may permit the electrically coupled epithelial cells of the ciliary body to conduct propagated action potentials. Images Fig. 2 PMID:2621623

  8. Cyclic-nucleotide–gated cation current and Ca2+-activated Cl current elicited by odorant in vertebrate olfactory receptor neurons

    PubMed Central

    Li, Rong-Chang; Ben-Chaim, Yair; Yau, King-Wai; Lin, Chih-Chun

    2016-01-01

    Olfactory transduction in vertebrate olfactory receptor neurons (ORNs) involves primarily a cAMP-signaling cascade that leads to the opening of cyclic-nucleotide–gated (CNG), nonselective cation channels. The consequent Ca2+ influx triggers adaptation but also signal amplification, the latter by opening a Ca2+-activated Cl channel (ANO2) to elicit, unusually, an inward Cl current. Hence the olfactory response has inward CNG and Cl components that are in rapid succession and not easily separable. We report here success in quantitatively separating these two currents with respect to amplitude and time course over a broad range of odorant strengths. Importantly, we found that the Cl current is the predominant component throughout the olfactory dose–response relation, down to the threshold of signaling to the brain. This observation is very surprising given a recent report by others that the olfactory-signal amplification effected by the Ca2+-activated Cl current does not influence the behavioral olfactory threshold in mice. PMID:27647918

  9. The effect of a self-constructed material on children’s physical activity during recess

    PubMed Central

    Méndez-Giménez, Antonio; Cecchini, José-Antonio; Fernández-Río, Javier

    2017-01-01

    ABSTRACT OBJECTIVE To analyze whether an intervention supported by free play with a self-constructed material increases the level of physical activity of students during recess. METHODS The participants were 166 children of third to sixth grade, between nine and 12 years old (average = 10.64; SS = 1.13). An experimental project was conducted with pre-test and post-test measurement, and a control group. Experimental group participants built cardboard paddles (third and fourth) and flying rings (fifth and sixth), a material they used freely for one week during recess. ActiGraph-GT3X accelerometers were used to measure physical activity. An ANOVA of repeated measures was used to find differences between groups and genders. RESULTS Significant intervention effects were found in the analyzed variables: sedentary activity (F = 38.19; p < 0.01), light (F = 76.56; p < 0.01), moderate (F = 27.44; p < 0.01), vigorous (F = 61.55; p < 0.01), and moderate and vigorous (F = 68.76; p < 0.01). Significant gender differences were shown (time × group × gender) for moderate (F = 6.58; p < 0.05) and vigorous (F = 5.51; p < 0.05) activity. CONCLUSIONS The self-constructed material is effective to increase the physical activity levels of children during recess; it decreases sedentary activity and light physical activity and increases the time devoted to moderate physical activity and vigorous physical activity, both in boys and in girls. The boys had an increase in vigorous physical activity and the girls in moderate physical activity. Due to its low cost, this strategy is recommended for administrators and teachers to increase the physical activity of children during recess. PMID:28678907

  10. Evaluation of recycled concrete aggregates for their suitability in construction activities: An experimental study.

    PubMed

    Puthussery, Joseph V; Kumar, Rakesh; Garg, Anurag

    2017-02-01

    Construction and demolition waste disposal is a major challenge in developing nations due to its ever increasing quantities. In this study, the recycling potential of waste concrete as aggregates in construction activities was studied. The metal leaching from the recycled concrete aggregates (RCA) collected from the demolition site of a 50year old building, was evaluated by performing three different leaching tests (compliance, availability and Toxic Characteristic Leaching Procedure). The metal leaching was found mostly within the permissible limit except for Hg. Several tests were performed to determine the physical and mechanical properties of the fine and coarse aggregates produced from recycled concrete. The properties of recycled aggregates were found to be satisfactory for their utilization in road construction activities. The suitability of using recycled fine and coarse aggregates with Portland pozzolanic cement to make a sustainable and environmental friendly concrete mix design was also analyzed. No significant difference was observed in the compressive strength of various concrete mixes prepared by natural and recycled aggregates. However, only the tensile strength of the mix prepared with 25% recycled fine aggregates was comparable to that of the control concrete. For other mixes, the tensile strength of the concrete was found to drop significantly. In summary, RCA should be considered seriously as a building material for road construction, mass concrete works, lightly reinforced sections, etc. The present work will be useful for the waste managers and policy makers particularly in developing nations where proper guidelines are still lacking. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Correlation Among Soil Enzyme Activities, Root Enzyme Activities, and Contaminant Removal in Two-Stage In Situ Constructed Wetlands Purifying Domestic Wastewater.

    PubMed

    Ni, Lixiao; Xu, Jiajun; Chu, Xianglin; Li, Shiyin; Wang, Peifang; Li, Yiping; Li, Yong; Zhu, Liang; Wang, Chao

    2016-07-01

    Two-stage in situ wetlands (two vertical flow constructed wetlands in parallel and a horizontal flow constructed wetland) were constructed for studying domestic wastewater purification and the correlations between contaminant removal and plant and soil enzyme activities. Results indicated the removal efficiency of NH4 (+) and NO3 (-) were significantly correlated with both urease and protease activity, and the removal of total phosphorus was significantly correlated with phosphatase activity. Chemical oxygen demand removal was not correlated with enzyme activity in constructed wetlands. Plant root enzyme (urease, phosphatase, protease and cellulose) activity correlation was apparent with all contaminant removal in the two vertical flow constructed wetlands. However, the correlation between the plant root enzyme activity and contaminant removal was poor in horizontal flow constructed wetlands. Results indicated that plant roots clearly played a role in the removal of contaminants.

  12. The American Library Association and International Relations: Accomplishments, Current Activities, Observations, Strategies, and Plan of Action.

    ERIC Educational Resources Information Center

    Doyle, Robert P.

    This report on the international relations activities of the American Library Association (ALA) briefly reviews ALA's policies and accomplishments in the international arena; describes ALA's current international activities and interests; outlines principles and values, which when correlated with current developments and past experience, provide…

  13. Reduction of Return Current Noise by Energy-Compensating Active Control

    NASA Astrophysics Data System (ADS)

    Azuma, Satoshi; Yamasakit, Hisanori; Itoh, Daisuke; Maruyama, Takafumi

    A newly proposed Energy-Compensating Active Control is implemented to reduce the return current noise which is caused by inverter-driven electric car systems. The Energy-Compensating Active Control detects the energy charged at the filter capacitor, reduces the energy and current of the noise frequency component by simple feedback loop incorporated with the conventional motor torque controller. No additional sensors or circuit arrangements are necessary, therefore the return current can be attenuated effectively without any further cost. The return current with an inverter system is measured using a current probe and a FFT analyzer, and it is shown that the 25Hz noise current is reduced by up to 10dB with the control. The results explain that the low frequency return current noise can be attenuated with the simple control scheme, which would expectedly reduce the size of filter reactors and capacitors to meet with the current limit level of signaling system's track relays.

  14. Electro-active sensor, method for constructing the same; apparatus and circuitry for detection of electro-active species

    NASA Technical Reports Server (NTRS)

    Buehler, Martin (Inventor)

    2009-01-01

    An electro-active sensor includes a nonconductive platform with a first electrode set attached with a first side of a nonconductive platform. The first electrode set serves as an electrochemical cell that may be utilized to detect electro-active species in solution. A plurality of electrode sets and a variety of additional electrochemical cells and sensors may be attached with the nonconductive platform. The present invention also includes a method for constructing the aforementioned electro-active sensor. Additionally, an apparatus for detection and observation is disclosed, where the apparatus includes a sealable chamber for insertion of a portion of an electro-active sensor. The apparatus allows for monitoring and detection activities. Allowing for control of attached cells and sensors, a dual-mode circuitry is also disclosed. The dual-mode circuitry includes a switch, allowing the circuitry to be switched from a potentiostat to a galvanostat mode.

  15. Constructed wetlands for wastewater and activated sludge treatment in north Greece: a review.

    PubMed

    Tsihrintzis, V A; Gikas, G D

    2010-01-01

    Constructed wetlands used for the treatment of urban, industrial and agricultural wastewater have become very popular treatment systems all over the world. In Greece, these systems are not very common, although the climate is favourable for their use. During recent years, there have been several attempts for the implementation of these systems in Greece, which include, among others, pilot-scale systems used for research, and full-scale systems designed and/or constructed to serve settlements or families. The purpose of this paper is the presentation of systems operating in Northern Greece, which have been studied by the Laboratory of Ecological Engineering and Technology of Democritus University of Thrace and others. A comparison is made of different system types, and the effect of various design and operational parameters is presented. Current research shows the good and continuous performance of these systems.

  16. Stabilization of activated fragments by shell-wise construction of an embedding environment.

    PubMed

    Krausbeck, Florian; Sobez, Jan-Grimo; Reiher, Markus

    2017-02-25

    An activated fragment which is structurally unstable when considered isolated can be stabilized through binding to a suitable molecular environment; for instance, to a transition-metal fragment. The metal fragment may be designed in a shell-wise build-up of a surrounding molecular environment. However, adding more and more atoms in a consecutive fashion soon leads to a combinatorial explosion of structures, which is unfeasible to handle without automation. Here, we present a fully automated and parallelized framework that constructs such an embedding environment atom-wise. Molecular realizations of such an environment are constructed based on simple heuristic rules intended to screen a sufficiently large portion of the possible compound space and are then subsequently optimized by electronic structure methods. (Constrained-optimized) structures are then evaluated with respect to a scoring function, for which we choose here the concept of gradient-driven molecule construction. This concept searches for structure modifications that reduce the forces on all atoms. We develop and analyze our approach at the example of CO2 activation by reproducing a known compound and mapping out possible alternative structures and their effect on the stabilization of a (bent) CO2 ligand. For all generated structures, the nuclear gradient on the activated fragment and its coordination energy are evaluated to steer the design process. © 2017 Wiley Periodicals, Inc.

  17. Activation processes on GaAs photocathode by different currents of oxygen source

    NASA Astrophysics Data System (ADS)

    Miao, Zhuang; Shi, Feng; Cheng, Hongchang; Wang, Shufei; Zhang, Xiaohui; Yuan, Yuan; Chen, Chang

    2015-04-01

    In order to know the influence of activation processes on GaAs photocathodes, three GaAs samples were activated by a fixed current of cesium source and different currents of oxygen source. The current of caesium source is same during activation to ensure initial adsorption of caesium quantum is similar, which is the base to show the difference during alternation activation of caesium and oxygen. Analysed with the activation data, it is indicated that Cs-to-O current ratio of 1.07 is the optimum ratio to obtain higher sensitivity and better stability. According to double dipole model, stable and uniform double dipole layers of GaAs-O-Cs:Cs-O-Cs are formed and negative electron affinity is achieved on GaAs surface by activation with cesium and oxygen. The analytical result is just coincident with the model. Thus there is an efficient technological method to improve sensitivity and stability of GaAs photocathode.

  18. Ionic currents during sustained pacemaker activity in rabbit sino-atrial myocytes.

    PubMed Central

    Zaza, A; Micheletti, M; Brioschi, A; Rocchetti, M

    1997-01-01

    1. The contribution of various ionic currents to diastolic depolarization (DD) in rabbit sinoatrial myocytes was evaluated by the action potential clamp technique. Individual currents were identified, during sustained pacemaking activity reproduced under voltage clamp conditions, according to their sensitivity to specific channel blockers. 2. The current sensitive to dihydropyridines (DHPs), blockers of L-type Ca2+ current (ICa,L), was small and outward during most of DD. Diastolic DHP-sensitive current was affected by changes in the driving force for K+, but it was insensitive to E-4031, which blocks the current termed IK,r; it was abolished by cell dialysis with a Ca2+ chelator. 3. The current sensitive to 2 mM Cs+ (ICs), a blocker of hyperpolarization-activated current (I(f)), was inward during the whole DD and it was substantially larger than the net inward current flowing during this phase. However, diastolic IK,r, identified in the same cells as the current sensitive to the blocker E-4031, exceeded ICs 2-fold. 4. These findings suggest that: (a) Ca2+ influx during the pacemaker cycle increases a K+ conductance, thus inverting the direction of the net current generated by L-type Ca2+ channel activity during DD; (b) the magnitude of I(f) would be adequate to account fully for DD; however, the coexistence of a larger IK,r suggests that other channels besides I(f) contribute inward current during this phase. PMID:9457645

  19. Constructive Fun.

    ERIC Educational Resources Information Center

    Simanek, Donald E.

    1994-01-01

    Compares and reviews currently available brands of steel construction sets that are useful to physics teachers for building demonstrations, prototypes of mechanisms, robotics, and remote control devices. (ZWH)

  20. Constructive Fun.

    ERIC Educational Resources Information Center

    Simanek, Donald E.

    1994-01-01

    Compares and reviews currently available brands of steel construction sets that are useful to physics teachers for building demonstrations, prototypes of mechanisms, robotics, and remote control devices. (ZWH)

  1. Photonic Network R&D Activities in Japan-Current Activities and Future Perspectives

    NASA Astrophysics Data System (ADS)

    Kitayama, Ken-Ichi; Miki, Tetsuya; Morioka, Toshio; Tsushima, Hideaki; Koga, Masafumi; Mori, Kazuyuki; Araki, Soichiro; Sato, Ken-Ichi; Onaka, Hiroshi; Namiki, Shu; Aoyama, Tomonori

    2005-10-01

    R&D activities on photonic networks in Japan are presented. First, milestones in current ongoing R&D programs supported by Japanese government agencies are introduced, including long-distance and wavelength division multiplexing (WDM) fiber transmission, wavelength routing, optical burst switching (OBS), and control-plane technology for IP backbone networks. Their goal was set to evolve a legacy telecommunications network to IP-over-WDM networks by introducing technologies for WDM and wavelength routing. We then discuss the perspectives of so-called PHASE II R&D programs for photonic networks over the next 5 years until 2010, by focusing on the report that has been recently issued by the Photonic Internet Forum (PIF), a consortium that has major carriers, telecom vendors, and Japanese academics as members. The PHASE II R&D programs should serve to establish a photonic platform to provide abundant bandwidth on demand, at any time on a real-time basis, through the customer's initiative to promote bandwidth-rich applications, such as grid computing, real-time digital-cinema streaming, medical and educational applications, and network storage in e-commerce.

  2. Relationship between construction workers' musculoskeletal disorders and occupational health service activities.

    PubMed

    Minna, Savinainen; Mika, Nyberg

    2012-01-01

    Construction work consists of numerous factors that influence workers' occupational health and that load the musculoskeletal system in particular. Musculoskeletal disorders are responsible for over a third of all sick leaves lasting over nine days in the construction industry. Occupational health services (OHS) were organized for 85% of the construction workers in our study. The proportion of construction workers who had suffered from chronic or repetitive neck and shoulder, shoulder or arm, or low-back disorders was 55.6%, 44.8% and 42.1%, respectively. Those who felt that they had received enough information, advice or guidance from OHS concerning work posture, work performance or work tools were more often those who had not suffered from shoulder or arm disorders (60.9% vs. 39.1%, p=.024, respectively) or low-back disorders (63.6% vs. 36.4%, p=.034, respectively) during the last month than those who had. Those who had received enough support from OHS concerning maintenance of work ability were more often workers who had not suffered from low-back disorders during the last month than those who had (63.3% vs. 36.7%, p=.004, respectively). OHS should focus more on workers who would really benefit from their activities at a particular time and in a particular situation (primary, secondary or tertiary prevention) and who are themselves devoted to improving their health.

  3. Principal component analysis of Birkeland currents determined by the Active Magnetosphere and Planetary Electrodynamics Response Experiment

    NASA Astrophysics Data System (ADS)

    Milan, S. E.; Carter, J. A.; Korth, H.; Anderson, B. J.

    2015-12-01

    Principal component analysis is performed on Birkeland or field-aligned current (FAC) measurements from the Active Magnetosphere and Planetary Electrodynamics Response Experiment. Principal component analysis (PCA) identifies the patterns in the FACs that respond coherently to different aspects of geomagnetic activity. The regions 1 and 2 current system is shown to be the most reproducible feature of the currents, followed by cusp currents associated with magnetic tension forces on newly reconnected field lines. The cusp currents are strongly modulated by season, indicating that their strength is regulated by the ionospheric conductance at the foot of the field lines. PCA does not identify a pattern that is clearly characteristic of a substorm current wedge. Rather, a superposed epoch analysis of the currents associated with substorms demonstrates that there is not a single mode of response, but a complicated and subtle mixture of different patterns.

  4. Principle Component Analysis of Birkeland Currents Determined by the Active Magnetosphere and Planetary Electrodynamics Response Experiment

    NASA Astrophysics Data System (ADS)

    Milan, S. E.; Carter, J. A.; Korth, H.; Anderson, B. J.

    2015-12-01

    Principle Component Analysis is performed on northern and southern hemisphere Birkeland or field-aligned current (FAC) measurements from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE). PCA identifies the patterns in the FACs that respond coherently to different aspects of geomagnetic activity. The region 1 and 2 current system is shown to be the most reproducible feature of the currents, followed by cusp currents associated with magnetic tension forces on newly-reconnected field lines. The cusp currents are strongly modulated by season, indicating that their strength is regulated by the ionospheric conductance at the foot of the field lines. PCA does not identify a pattern that is clearly characteristic of a substorm current wedge. Rather, a superposed epoch analysis of the currents associated with substorms demonstrates that there is not a single mode of response, but a complicated and subtle mixture of different patterns. Other interhemispheric differences are discussed.

  5. Heterotrophic bacterial activities and treatment performance of surface flow constructed wetlands receiving woodwaste leachate.

    PubMed

    Tao, Wendong; Hall, Ken J; Duff, Sheldon J B

    2006-07-01

    Heterotrophic activities were investigated by measuring 3H-leucine incorporation to bacterial protein and 14C-glucose turnover in surface flow constructed wetlands receiving woodwaste leachate. No significant longitudinal variation was found in heterotrophic activities of bacterioplankton. An open wetland, a vegetated wetland, and a fertilized vegetated wetland were used to examine the effects of vegetation and ammonium nitrate amendment. There was not a significant difference in treatment performance among the three wetlands, except for a significant pH increase and more efficient volatile fatty acids removal in the fertilized wetland. The fertilized wetland had the highest leucine incorporation rate and shortest glucose turnover time accompanied by the lowest glucose mineralization percentage, followed by the open wetland, then the vegetated wetland. Planktonic and sedimentary bacteria contributed to the majority of the total heterotrophic activities; epiphytic bacteria played a minor role. Heterotrophic activities were influenced by the availability of nutrient, electron acceptor, and organic substrate.

  6. Parent's Interests, Current Involvement and Level of Parental Involvement in School Activities.

    ERIC Educational Resources Information Center

    Gbadamosi, Tara; Lin, Huey-Ling

    This study examined what school activities parents were involved in and the relationship between parents' interests and level of participation. Parents completed self-report questionnaires examining activities they were currently involved in and activities they would like to do in their children's classrooms. Out of 208 surveys distributed, 114…

  7. A review of the outcome expectancy construct in physical activity research.

    PubMed

    Williams, David M; Anderson, Eileen S; Winett, Richard A

    2005-02-01

    Outcome expectancy is a central construct in social cognitive models of health behavior widely used as frameworks for physical activity research. This article provides a review of the outcome expectancy construct and its application to research on physical activity. Theoretical articles describing definitions and placement of outcome expectancy within social cognitive models, as well as empirical research on outcome expectancy and physical activity, were reviewed. Self-efficacy theory, the transtheoretical model, the theory of planned behavior, and protection motivation theory differ in their labeling and conceptualization of outcome expectancy but unanimously include expected outcomes of behavior. Preliminary empirical investigation of the role of outcome expectancy in understanding physical activity has yielded mixed results. Positive outcome expectancy appears to be more predictive of physical activity in older adults than in young to middle-aged adults, and personal barriers appear to be the most predictive subtype of negative outcome expectancy. In addition, a small number of studies indicate relations between outcome expectancy and other theoretical variables, including behavioral intention, stage of change, and self-efficacy. Further research on the role of outcome expectancy is necessary to design effective physical activity interventions. New directions in outcome expectancy research could involve (a) expanding the conceptualization of outcome expectancy to include expected outcomes of sedentary behavior and affective responses to physical activity, (b) further examination of potential moderators of the relation between outcome expectancy and physical activity (such as outcome value and outcome proximity), (c) distinguishing between the role of outcome expectancy in behavior onset versus behavior maintenance, (d) examining outcome expectancy as a mechanism of change in environmental intervention approaches, and (e) further analysis of interrelations

  8. Agreement between current and active asthma classification methods, Asthma Call-back Survey, 2011-2012.

    PubMed

    Dodd, Katelynn E; Mazurek, Jacek M

    2016-10-01

    Various approaches have been developed to identify persons with asthma using survey data. To assess agreement between current and active asthma classifications, 2011-2012 Asthma Call-back Survey landline telephone household data from 38 states, District of Columbia, and Puerto Rico for adults aged ≥18 years who have ever been told by a health professional they have asthma were analyzed. Respondents were classified to have current asthma if they reported still having asthma, and active asthma if they reported within the past year: 1) talking to a doctor about asthma, 2) taking asthma medication, or 3) having any symptoms of asthma. Agreement between classifications was assessed using the Kappa statistic. Among adults ever told by a health professional they have asthma, an estimated 72% had current asthma and 75% had active asthma. Overall, 67% of individuals met classifications of both current and active asthma and 20% had neither current nor active asthma (Kappa = 0.68). The Kappa increased to 0.72 when talking to a doctor about asthma was removed from the active asthma classification. Results indicated substantial agreement between current and active asthma. Agreement was strengthened when talking to a doctor about asthma was removed from the active asthma classification.

  9. Physical activity (PA) among middle-aged women: initial and current influences and patterns of participation.

    PubMed

    Codina, Nuria; Pestana, José V; Armadans, Immaculada

    2013-01-01

    This study investigated the initial and current influences for doing physical activity (PA), current levels of PA participation, and future plans for it. Participants were 200 women aged 45 to 64 years old. Factor loadings of influences were explored using Principal Components Analysis. Pearson bivariate correlations, t-test, and ANOVA were used to show the differences among the influences, sociodemographic characteristics, and present/future PA participation. Personal fulfillment was the main initial influence, while health benefits/self-care, and outdoor/family activities were the most important current influences. The results highlight the factors that best explain present PA participation and also plans for activity in the future.

  10. Early-life exposure to caffeine affects the construction and activity of cortical networks in mice.

    PubMed

    Fazeli, Walid; Zappettini, Stefania; Marguet, Stephan Lawrence; Grendel, Jasper; Esclapez, Monique; Bernard, Christophe; Isbrandt, Dirk

    2017-09-01

    The consumption of psychoactive drugs during pregnancy can have deleterious effects on newborns. It remains unclear whether early-life exposure to caffeine, the most widely consumed psychoactive substance, alters brain development. We hypothesized that maternal caffeine ingestion during pregnancy and the early postnatal period in mice affects the construction and activity of cortical networks in offspring. To test this hypothesis, we focused on primary visual cortex (V1) as a model neocortical region. In a study design mimicking the daily consumption of approximately three cups of coffee during pregnancy in humans, caffeine was added to the drinking water of female mice and their offspring were compared to control offspring. Caffeine altered the construction of GABAergic neuronal networks in V1, as reflected by a reduced number of somatostatin-containing GABA neurons at postnatal days 6-7, with the remaining ones showing poorly developed dendritic arbors. These findings were accompanied by increased synaptic activity in vitro and elevated network activity in vivo in V1. Similarly, in vivo hippocampal network activity was altered from the neonatal period until adulthood. Finally, caffeine-exposed offspring showed increased seizure susceptibility in a hyperthermia-induced seizure model. In summary, our results indicate detrimental effects of developmental caffeine exposure on mouse brain development. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Ca(2+)-activated K current in the ARC muscle of Aplysia.

    PubMed

    Brezina, V; Weiss, K R

    1995-03-01

    1. This work continues our examination of the electrophysiology and contractions of single, functionally intact fibers dissociated from a widely studied molluscan muscle, the accessory radula closer (ARC) muscle of Aplysia californica, aimed at understanding its excitation-contraction mechanisms and their modulation. Extensive previous work has characterized a number of ion currents in the fibers. 2. Here we describe an additional major current that could not be studied earlier because, unlike all of the other currents in the ARC muscle fibers, it becomes prominent only during contraction of the fiber. It is a Ca(2+)-activated K current, associated with contraction most likely because both are activated by the same elevation in intracellular free Ca2+. 3. We used several manipulations to elicit the Ca(2+)-activated K current and contraction: depolarizing voltage steps in the presence of extracellular Ca2+, application of caffeine in the presence or absence of extracellular Ca2+ (and thus presumably working by releasing Ca2+ from intracellular stores), application of the Ca(2+)-ionophore A23187, and direct iontophoretic injection of Ca2+ into the fiber. 4. The Ca(2+)-activated K current reversed around -70 mV, not far from EK, and the reversal potential shifted substantially with elevated extracellular K+. Activation of the current was not only Ca2+ dependent, but also quite strongly voltage dependent, promoted by depolarization. The current was well blocked by tetraethylammonium (KD approximately 2 mM), but not blocked by even 10 mM 4-aminopyridine or low concentrations of the K-current blocking toxins charybdotoxin and apamin. 5. After a depolarizing voltage step in Ca(2+)-containing solution, the Ca(2+)-activated K current appeared, often with some delay, as a large peak of current that soon disintegrated into a prolonged period of individual oscillatory transients of Ca(2+)-activated K current, sometimes correlated with transient contractions. Similar transients

  12. Design, construction, activation, and operation of a high intensity acoustic test chamber

    NASA Technical Reports Server (NTRS)

    Kamel, L. T.

    1986-01-01

    The design philosophy, construction, integration, and activation of the high intensity acoustic test chamber for production acceptance testing of satellites are discussed. The 32,000 cubic-foot acoustic test cell consists of a steel reinforced concrete chamber with six electropneumatic noise generators. One of the innovative features of the chamber is a unique quarter horn assembly that acoustically couples the noise generators to the chamber. Design concepts, model testing, and evaluation results are presented. Considerations such as nitrogen versus compressed air source, digital closed loop spectrum control versus manual equalizers, and microprocessor based interlock systems are included. Construction difficulties, anomalies encountered, and their resolution are also discussed. Results of the readiness testing are highlighted.

  13. Design, construction, activation, and operation of a high intensity acoustic test chamber

    NASA Technical Reports Server (NTRS)

    Kamel, L. T.

    1986-01-01

    The design philosophy, construction, integration, and activation of the high intensity acoustic test chamber for production acceptance testing of satellites are discussed. The 32,000 cubic-foot acoustic test cell consists of a steel reinforced concrete chamber with six electropneumatic noise generators. One of the innovative features of the chamber is a unique quarter horn assembly that acoustically couples the noise generators to the chamber. Design concepts, model testing, and evaluation results are presented. Considerations such as nitrogen versus compressed air source, digital closed loop spectrum control versus manual equalizers, and microprocessor based interlock systems are included. Construction difficulties, anomalies encountered, and their resolution are also discussed. Results of the readiness testing are highlighted.

  14. Pathological impact of hyperpolarization-activated chloride current peculiar to rat pulmonary vein cardiomyocytes.

    PubMed

    Okamoto, Yosuke; Kawamura, Koichi; Nakamura, Yuta; Ono, Kyoichi

    2014-01-01

    Pulmonary veins (PVs) are believed to be a crucial origin of atrial fibrillation. We recently reported that rat PV cardiomyocytes exhibit arrhythmogenic automaticity in response to norepinephrine. Herein, we further characterized the electrophysiological properties underlying the potential arrhythmogenicity of PV cardiomyocytes. Patch clamping studies revealed a time dependent hyperpolarization-activated inward current in rat PV cardiomyocytes, but not in left atrial (LA) myocytes. The current was Cs(+) resistant, and was not affected by removal of external Na(+) or K(+). The current was inhibited with Cd(2+), and the reversal potential was sensitive to changes in [Cl(-)] on either side of the membrane in a manner consistent with a Cl(-) selective channel. Cl(-) channel blockers attenuated the current, and slowed or completely inhibited the norepinephrine-induced automaticity. The biophysical properties of the hyperpolarization-activated Cl(-) current in rat PVs were different from those of ClC-2 currents previously reported: (i) the voltage-dependent activation of the Cl(-) current in rat PVs was shifted to negative potentials as [Cl(-)]i increased, (ii) the Cl(-) current was enhanced by extracellular acidification, and (iii) extracellular hyper-osmotic stress increased the current, whereas hypo-osmotic cell swelling suppressed the current. qPCR analysis revealed negligible ClC-2 mRNA expression in the rat PV. These findings suggest that rat PV cardiomyocytes possess a peculiar voltage-dependent Cl(-) channel, and that the channel may play a functional role in norepinephrine-induced automaticity.

  15. Large-conductance calcium-activated potassium current modulates excitability in isolated canine intracardiac neurons

    PubMed Central

    Pérez, Guillermo J.; Desai, Mayurika; Anderson, Seth

    2013-01-01

    We studied principal neurons from canine intracardiac (IC) ganglia to determine whether large-conductance calcium-activated potassium (BK) channels play a role in their excitability. We performed whole cell recordings in voltage- and current-clamp modes to measure ion currents and changes in membrane potential from isolated canine IC neurons. Whole cell currents from these neurons showed fast- and slow-activated outward components. Both current components decreased in the absence of calcium and following 1–2 mM tetraethylammonium (TEA) or paxilline. These results suggest that BK channels underlie these current components. Single-channel analysis showed that BK channels from IC neurons do not inactivate in a time-dependent manner, suggesting that the dynamic of the decay of the fast current component is akin to that of intracellular calcium. Immunohistochemical studies showed that BK channels and type 2 ryanodine receptors are coexpressed in IC principal neurons. We tested whether BK current activation in these neurons occurred via a calcium-induced calcium release mechanism. We found that the outward currents of these neurons were not affected by the calcium depletion of intracellular stores with 10 mM caffeine and 10 μM cyclopiazonic acid. Thus, in canine intracardiac neurons, BK currents are directly activated by calcium influx. Membrane potential changes elicited by long (400 ms) current injections showed a tonic firing response that was decreased by TEA or paxilline. These data strongly suggest that the BK current present in canine intracardiac neurons regulates action potential activity and could increase these neurons excitability. PMID:23195072

  16. 77 FR 14817 - Agency Information Collection Activities: Form I-829, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-13

    ... SECURITY Citizenship and Immigration Services Agency Information Collection Activities: Form I-829, Extension of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection Under Review: Form I- 829, Petition by Entrepreneur to Remove Conditions. The...

  17. 75 FR 77939 - Agency Information Collection Activities; Revision of a Currently Approved Information Collection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-14

    ... controls of motor carriers. On September 9, 2010, FMCSA published a Federal Register notice allowing for a... Federal Motor Carrier Safety Administration Agency Information Collection Activities; Revision of a Currently Approved Information Collection Request: Accident Recordkeeping Requirements AGENCY: Federal Motor...

  18. 78 FR 13932 - Agency Information Collection Activities; Approval of a Currently Approved Information Collection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-01

    ... Federal Motor Carrier Safety Administration Agency Information Collection Activities; Approval of a Currently Approved Information Collection Request: Financial Responsibility for Motor Carriers of Passengers... tura.gatling@dot.gov and gerald.folsom@dot.gov . SUPPLEMENTARY INFORMATION: Title:...

  19. 78 FR 12789 - Agency Information Collection Activities; Extension of a Currently Approved Collection: Office on...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-25

    ... coalition, State domestic violence coalition; territorial domestic violence or sexual assault coalition... Information Collection Activities; Extension of a Currently Approved Collection: Office on Violence Against Women Solicitation Template ACTION: 60-Day Notice. The Department of Justice, Office on Violence Against...

  20. 76 FR 2143 - Agency Information Collection Activities: Revision and Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-12

    ... Employment and Training Administration Agency Information Collection Activities: Revision and Extension of a Currently Approved Information Collection; Comment Request AGENCY: Employment and Training Administration... general public and Federal agencies with an opportunity to comment on a continuing collection of...

  1. 78 FR 25763 - Agency Information Collection Activities Under OMB Review; Renewal of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-02

    ... Bureau of Reclamation Agency Information Collection Activities Under OMB Review; Renewal of a Currently Approved Information Collection AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of renewal and request for comments. SUMMARY: The Bureau of Reclamation has forwarded the following Information...

  2. 77 FR 59666 - Agency Information Collection Activities; Extension of a Currently Approved Collection; Comments...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-28

    ... of Justice Programs Agency Information Collection Activities; Extension of a Currently Approved Collection; Comments Requested: School Crime Supplement (SCS) to the National Crime Victimization Survey... comments from the public and affected agencies. This proposed information collection was previously...

  3. 77 FR 17523 - Agency Information Collection Activities: Extension of a Currently Approved Collection; Comments...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-26

    .../collection: National Crime Victimization Survey. (3) Agency form number, if any, and the applicable component... of Justice Programs Agency Information Collection Activities: Extension of a Currently Approved Collection; Comments Requested; National Crime Victimization Survey (NCVS) ACTION: 60-day Notice of...

  4. 75 FR 51484 - Agency Information Collection Activities: Extension of a Currently Approved Information...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-20

    ... information collection under review: Form ETA- 750, Application for Alien Employment Certification; OMB... information collected in its temporary and permanent certification programs for the employment of alien... Information Collection Activities: Extension of a Currently Approved Information Collection With Non...

  5. 77 FR 76097 - Agency Information Collection Activities: Renewal of Currently Approved Collection; Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-26

    ... TRANSPARENCY BOARD Agency Information Collection Activities: Renewal of Currently Approved Collection; Comment Request AGENCY: Recovery Accountability and Transparency Board. ACTION: Notice and request for comments. SUMMARY: The Recovery Accountability and Transparency Board (Board) invites comments on the proposed...

  6. Construction of a Highly Active Xylanase Displaying Oleaginous Yeast: Comparison of Anchoring Systems

    PubMed Central

    Duquesne, Sophie; Bozonnet, Sophie; Bordes, Florence; Dumon, Claire; Nicaud, Jean-Marc; Marty, Alain

    2014-01-01

    Three Yarrowia lipolytica cell wall proteins (YlPir, YlCWP1 and YlCBM) were evaluated for their ability to display the xylanase TxXYN from Thermobacillus xylanilyticus on the cell surface of Y. lipolytica. The fusion proteins were produced in Y. lipolytica JMY1212, a strain engineered for mono-copy chromosomal insertion, and enabling accurate comparison of anchoring systems. The construction using YlPir enabled cell bound xylanase activity to be maximised (71.6 U/g). Although 48% of the activity was released in the supernatant, probably due to proteolysis at the fusion zone, this system is three times more efficient for the anchoring of TxXYN than the YlCWP1 system formerly developed for Y. lipolytica. As far as we know it represents the best displayed xylanase activity ever published. It could be an attractive alternative anchoring system to display enzymes in Y. lipolytica. PMID:24743311

  7. Trail user demographics, physical activity behaviors, and perceptions of a newly constructed greenway trail.

    PubMed

    Price, Anna E; Reed, Julian A; Muthukrishnan, Suresh

    2012-10-01

    To better understand and promote physical activity on a newly constructed trail, the present study examined the demographic characteristics and physical activity behaviors of trail users; the demographic characteristics of trail users compared to the demographic profile Greenville County, South Carolina residents; trail users' purpose for using the trail; the distance trail users traveled to access the trail from their homes; channels through which trail users learned about the trail; and trail characteristics liked by trail users. Using a valid and reliable intercept survey, 1,148 trail users were interviewed. Trail users were mostly white (93.1%), male (59.1%) adults (84.2%) who reported using the trail for exercise (91%). Significant associations were identified between trail user demographic characteristics and how trail users learned about the trail and trail characteristics liked by trail users. The findings may contribute to the development of targeted health promotion efforts to promote physical activity on this and similar trails.

  8. [Resource activation in clinical psychology and psychotherapy: review of theoretical issues and current research].

    PubMed

    Groß, L J; Stemmler, M; de Zwaan, M

    2012-08-01

    This review summarises theoretical issues and current research on working with clients' resources and strengths in clinical psychology and psychotherapy. Resource activation is considered as an important common factor in psychotherapy. In general, resource activation means an explicit focus on resources, strengths and potentials of the clients. After defining the term resources, considerations with regard to therapeutic attitude, principles of resource activation, approaches to resource diagnostics and different research strategies are presented. Current research focuses especially on the relation between resource activation and process variables in out-patient treatment. © Georg Thieme Verlag KG Stuttgart · New York.

  9. Effects of current physical activity on affective response to exercise: Physical and social-cognitive mechanisms

    PubMed Central

    Magnan, Renee E.; Kwan, Bethany M.; Bryan, Angela D.

    2012-01-01

    Objective Affective responses during exercise are often important determinants of exercise initiation and maintenance. Current physical activity may be one individual difference that is associated with the degree to which individuals have positive (or negative) affective experiences during exercise. The objective of this investigation was to explore physical and cognitive explanations of the relationship between current activity status (more versus less active) and affective response during a 30-minute bout of moderate-intensity exercise. Method Participants reported their current level of physical activity, exercise self-efficacy, and affect during a 30-minute bout of moderate-intensity exercise. Results More active individuals experienced higher levels of positive affect and tranquility and lower levels of negative affect and fatigue during exercise. Multivariate models for each affective state indicated separate processes through which physical activity may be associated with changes in affect during exercise. Conclusions These models indicate that affect experienced during physical activity is related to current activity level and these relationships can be partially explained by the physical and cognitive factors explored in this study. Recommendations for future research to elucidate whether positive affective response to physical activity improves as a function of becoming more active over time are discussed. PMID:23088712

  10. Genetic activation of BK currents in vivo generates bidirectional effects on neuronal excitability

    PubMed Central

    Montgomery, Jenna R.; Meredith, Andrea L.

    2012-01-01

    Large-conductance calcium-activated potassium channels (BK) are potent negative regulators of excitability in neurons and muscle, and increasing BK current is a novel therapeutic strategy for neuro- and cardioprotection, disorders of smooth muscle hyperactivity, and several psychiatric diseases. However, in some neurons, enhanced BK current is linked with seizures and paradoxical increases in excitability, potentially complicating the clinical use of agonists. The mechanisms that switch BK influence from inhibitory to excitatory are not well defined. Here we investigate this dichotomy using a gain-of-function subunit (BKR207Q) to enhance BK currents. Heterologous expression of BKR207Q generated currents that activated at physiologically relevant voltages in lower intracellular Ca2+, activated faster, and deactivated slower than wild-type currents. We then used BKR207Q expression to broadly augment endogenous BK currents in vivo, generating a transgenic mouse from a circadian clock-controlled Period1 gene fragment (Tg-BKR207Q). The specific impact on excitability was assessed in neurons of the suprachiasmatic nucleus (SCN) in the hypothalamus, a cell type where BK currents regulate spontaneous firing under distinct day and night conditions that are defined by different complements of ionic currents. In the SCN, Tg-BKR207Q expression converted the endogenous BK current to fast-activating, while maintaining similar current-voltage properties between day and night. Alteration of BK currents in Tg-BKR207Q SCN neurons increased firing at night but decreased firing during the day, demonstrating that BK currents generate bidirectional effects on neuronal firing under distinct conditions. PMID:23112153

  11. 40 CFR 1611.7 - Testimony by current CSB employees regarding prior activity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Testimony by current CSB employees regarding prior activity. 1611.7 Section 1611.7 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD TESTIMONY BY EMPLOYEES IN LEGAL PROCEEDINGS § 1611.7 Testimony by current CSB employees...

  12. 40 CFR 1611.7 - Testimony by current CSB employees regarding prior activity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Testimony by current CSB employees regarding prior activity. 1611.7 Section 1611.7 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD TESTIMONY BY EMPLOYEES IN LEGAL PROCEEDINGS § 1611.7 Testimony by current CSB employees...

  13. 40 CFR 1611.7 - Testimony by current CSB employees regarding prior activity.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Testimony by current CSB employees regarding prior activity. 1611.7 Section 1611.7 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD TESTIMONY BY EMPLOYEES IN LEGAL PROCEEDINGS § 1611.7 Testimony by current CSB employees...

  14. 40 CFR 1611.7 - Testimony by current CSB employees regarding prior activity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Testimony by current CSB employees regarding prior activity. 1611.7 Section 1611.7 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD TESTIMONY BY EMPLOYEES IN LEGAL PROCEEDINGS § 1611.7 Testimony by current CSB employees...

  15. Planar fuel cell utilizing nail current collectors for increased active surface area

    DOEpatents

    George, Thomas J.; Meacham, G. B. Kirby

    2002-03-26

    A plurality of nail current collector members are useful in the gas flow passages of an electrochemical device to optimize the active surfaces of the device and to provide structural support. In addition, the thicknesses of cathode and anode layers within the electrochemical device are varied according to current flow through the device to reduce resistance and increase operating efficiency.

  16. 76 FR 68786 - Agency Information Collection Activities: Extension of a Currently Approved Collection; Annual...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-07

    ... annual progress report is 2,556 hours. If additional information is required contact: Jerri Murray... Activities: Extension of a Currently Approved Collection; Annual Progress Report for the STOP Formula Grants... Information Collection: Extension of a currently approved collection. (2) Title of the Form/Collection:...

  17. Planar fuel cell utilizing nail current collectors for increased active surface area

    SciTech Connect

    George, Thomas J.; Meacham, G.B. Kirby

    1999-11-26

    A plurality of nail current collector members are useful in the gas flow passages of an electrochemical device to optimize the active surfaces of the device and to provide structural support. In addition, the thicknesses of cathode and anode layers within the electrochemical device are varied according to current flow through the device to reduce resistance and increase operating efficiency.

  18. 76 FR 63320 - Agency Information Collection Activities: Form N-470, Revision of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-12

    ... Agency Information Collection Activities: Form N-470, Revision of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection Under Review: Form N- 470... revision of Form N-470 instead of extending the current edition. USCIS invites members of the public who...

  19. Self-control constructs related to measures of dietary intake and physical activity in adolescents.

    PubMed

    Wills, Thomas A; Isasi, Carmen R; Mendoza, Don; Ainette, Michael G

    2007-12-01

    To test self-regulation concepts in relation to dietary intake and physical activity patterns in adolescence, which we predicted to be influenced by components of a self-control model. A survey was conducted with a multiethnic sample of 9th grade public school students in a metropolitan area (N = 539). Confirmatory analysis tested the measurement structure of self-control. Structural equation modeling tested the association of self-control constructs with measures of fruit and vegetable intake, saturated fat intake, physical activity, and sedentary behavior. Confirmatory analysis of 14 indicators of self-control showed best fit for a two-factor structure, with latent constructs of good self-control (planfulness) and poor self-control (impulsiveness). Good self-control was related to more fruit and vegetable intake, more participation in sports, and less sedentary behavior. Poor self-control was related to more saturated fat intake and less vigorous exercise. These effects were independent of gender, ethnicity, and parental education, which themselves had relations to diet and exercise measures. Multiple-group modeling indicated that effects of self-control were comparable across gender and ethnicity subgroups. Self-control concepts are relevant for patterns of dietary intake and physical activity among adolescents. Attention to self-control processes may be warranted for prevention programs to improve health behaviors in childhood and adolescence.

  20. Sensory deprivation regulates the development of the hyperpolarization-activated current in auditory brainstem neurons.

    PubMed

    Hassfurth, Benjamin; Magnusson, Anna K; Grothe, Benedikt; Koch, Ursula

    2009-10-01

    Hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels are highly expressed in the superior olivary complex, the primary locus for binaural information processing. This hyperpolarization-activated current (I(h)) regulates the excitability of neurons and enhances the temporally precise analysis of the binaural acoustic cues. By using the whole-cell patch-clamp technique, we examined the properties of I(h) current in neurons of the lateral superior olive (LSO) and the medial nucleus of the trapezoid body (MNTB) before and after hearing onset. Moreover, we tested the hypothesis that I(h) currents are actively regulated by sensory input activity by performing bilateral and unilateral cochlear ablations before hearing onset, resulting in a chronic auditory deprivation. The results show that after hearing onset, I(h) currents are rapidly upregulated in LSO neurons, but change only marginally in neurons of the MNTB. We also found a striking difference in maximal current density, voltage dependence and activation time constant between the LSO and the MNTB in mature-like animals. Following bilateral cochlear ablations before hearing onset, the I(h) currents were scaled up in the LSO and scaled down in the MNTB. Consequently, in the LSO this resulted in a depolarized resting membrane potential and a lower input resistance of these neurons. This type of activity-dependent homeostatic change could thus result in an augmented response to the remaining inputs.

  1. Duration differences of corticostriatal responses in striatal projection neurons depend on calcium activated potassium currents

    PubMed Central

    Arias-García, Mario A.; Tapia, Dagoberto; Flores-Barrera, Edén; Pérez-Ortega, Jesús E.; Bargas, José; Galarraga, Elvira

    2013-01-01

    The firing of striatal projection neurons (SPNs) exhibits afterhyperpolarizing potentials (AHPs) that determine discharge frequency. They are in part generated by Ca2+-activated K+-currents involving BK and SK components. It has previously been shown that suprathreshold corticostriatal responses are more prolonged and evoke more action potentials in direct pathway SPNs (dSPNs) than in indirect pathway SPNs (iSPNs). In contrast, iSPNs generate dendritic autoregenerative responses. Using whole cell recordings in brain slices, we asked whether the participation of Ca2+-activated K+-currents plays a role in these responses. Secondly, we asked if these currents may explain some differences in synaptic integration between dSPNs and iSPNs. Neurons obtained from BAC D1 and D2 GFP mice were recorded. We used charybdotoxin and apamin to block BK and SK channels, respectively. Both antagonists increased the depolarization and delayed the repolarization of suprathreshold corticostriatal responses in both neuron classes. We also used NS 1619 and NS 309 (CyPPA), to enhance BK and SK channels, respectively. Current enhancers hyperpolarized and accelerated the repolarization of corticostriatal responses in both neuron classes. Nevertheless, these drugs made evident that the contribution of Ca2+-activated K+-currents was different in dSPNs as compared to iSPNs: in dSPNs their activation was slower as though calcium took a diffusion delay to activate them. In contrast, their activation was fast and then sustained in iSPNs as though calcium flux activates them at the moment of entry. The blockade of Ca2+-activated K+-currents made iSPNs to look as dSPNs. Conversely, their enhancement made dSPNs to look as iSPNs. It is concluded that Ca2+-activated K+-currents are a main intrinsic determinant causing the differences in synaptic integration between corticostriatal polysynaptic responses between dSPNs and iSPNs. PMID:24109439

  2. Voltage-activated currents in somatic muscle of the nematode parasite Ascaris suum.

    PubMed

    Martin, R J; Thorn, P; Gration, K A; Harrow, I D

    1992-12-01

    1. Voltage-activated currents in cell bodies of the somatic muscle cells of Ascaris suum were studied using a two-microelectrode voltage-clamp technique. Cells recorded from had resting membrane potentials around -35 mV and had input conductances in the range 1-10 microS. 2. In cells bathed in artificial perienteric fluid, depolarizing steps from a holding potential of -35 mV elicited outward currents at a threshold of -15 mV. These currents had inwardly directed inflections on the rising phase, suggesting the presence of more than one current. Hyperpolarizing steps did not activate current. 3. Tetraethylammonium (TEA+, 69 mmol l-1) blocked the outward currents and allowed a voltage-dependent inactivating Ca2+ current to be observed. The peak current-voltage relationship was U-shaped with a threshold around -15 mV and peak at +5 mV. The reversal potential of the Ca2+ current was estimated by extrapolation to be +45 mV. 4. The permeability of the voltage-activated outward currents was studied by examining reversal potentials of tail currents. The reversal potentials were linearly dependent on the logarithm of the extracellular potassium concentration if extracellular [K+] was greater than 10 mmol l-1. The Na+/K+ permeability ratio of the currents was 0.04. 5. Inactivation, seen as a decline following the peak of the K+ current, was produced by maintained depolarization. The recovery from inactivation was complex and could be described by the sum of two exponentials with time constants of 0.67 s and 20.1 s. Steady-state inactivation of the K+ currents was observed at a range of holding potentials. Only a proportion (34%) of the total K+ current was inactivated by holding potentials more positive than -20 mV. 6. Extracellular application of 5 mmol l-1 4-aminopyridine (4-AP) selectively abolished an early fast component of the K+ current (the peak). The 4-AP-sensitive current decayed quickly with a time constant of around 10 ms; a Boltzmann fit to its activation curve

  3. Design, construction, and testing of a five active axes magnetic bearing system

    NASA Technical Reports Server (NTRS)

    Delprete, Cristiana; Genta, Giancarlo; Carabelli, Stefano

    1994-01-01

    A high speed electric spindle based on active electromagnetic suspension technology has been designed, built, and tested. The main goal of the research work was the construction of a highly modular unit which can be used for teaching and research purposes. The design of the electromechanical components and of the control unit is described in detail, together with the characterization tests performed on the various subsystems. A description of the preliminary tests on the unit, conducted at speeds not in excess of the first deformation critical speed of the rotor, concludes the work.

  4. Brief Physical Activity-Related Psychosocial Measures: Reliability and Construct Validity

    PubMed Central

    Carlson, Jordan A.; Sallis, James F.; Wagner, Nicole; Calfas, Karen J.; Patrick, Kevin; Groesz, Lisa M.; Norman, Gregory J.

    2015-01-01

    Background Psychosocial factors have been related to physical activity (PA) and are used to evaluate mediation in PA interventions. Methods Brief theory-based psychosocial scales were compiled from existing measures and evaluated. Study 1 assessed factor structure and construct validity with self-reported PA and accelerometry in overweight/obese men (N = 441) and women (N = 401). Study 2 assessed 2-week reliability and internal consistency in 49 college students. Results Confirmatory factor analysis indicated good fit in men and women (CFI = .90; RMSEA = .05). Construct validity was supported for change strategies (r = .29–.46), self-efficacy (r = .19–.22) and enjoyment (r = .21–.33) in men and women, and for cons in women (r = –.19 to –.20). PA pros (r = −.02 to .11) and social support (r = −.01 to .12) were not supported for construct validity. Test-retest reliability ICCs ranged from .49–.81. Internal consistency alphas ranged from .55–.90. Reliability was supported for most scales with further testing needed for cons (alphas = .55–.63) and enjoyment (ICC = .49). Conclusions Many of the brief scales demonstrated adequate reliability and validity, while some need further development. The use of these scales could advance research and practice in the promotion of PA. PMID:22207589

  5. Negative-shift activation, current reduction and resurgent currents induced by β-toxins from Centruroides scorpions in sodium channels.

    PubMed

    Schiavon, Emanuele; Pedraza-Escalona, Martha; Gurrola, Georgina B; Olamendi-Portugal, Timoteo; Corzo, Gerardo; Wanke, Enzo; Possani, Lourival D

    2012-02-01

    The β-toxins purified from the New World scorpion venoms of the Centruroides species affect several voltage-gated sodium channels (VGSCs) and thus are essential tools not only for the discrimination of different channel sub-types but also for studying the structure-function relationship between channels and toxins. This communication reports the results obtained with four different peptides purified from three species of Centruroides scorpions and assayed on seven distinct isoforms of VGSC (Na(v)1.1-Na(v)1.7) by specific functional analysis conducted through single cell electrophysiology. The toxins studied were CssII from Centruroides suffusus suffusus, Cll1 and Cll2 from Centruroides limpidus limpidus and a novel toxin from Centruroides noxius, which was characterized for the first time here. It has 67 amino acid residues and four disulfide bridges with a molecular mass of 7626 Da. Three different functional features were identified: current reduction of macroscopic conductance, left shift of the voltage-dependent activation and induction of resurgent currents at negative voltages following brief, strong depolarizations. The isoforms which revealed to be more affected resulted to be Na(v)1.6 > 1.1 > 1.2 and, for the first time, a β-toxin is here shown to induce resurgent current also in isoforms different from Na(v)1.6. Additionally, these results were analyzed with molecular modelling. In conclusion, although the four toxins have a high degree of identity, they display tri-modal function, each of which shows selectivity among the different sub-types of Na+ -channels. Thus, they are invaluable as tools for structure-function studies of β-toxins and offer a basis for the design of novel ion channel-specific drugs.

  6. THE EVOLUTION OF THE ELECTRIC CURRENT DURING THE FORMATION AND ERUPTION OF ACTIVE-REGION FILAMENTS

    SciTech Connect

    Wang, Jincheng; Yan, Xiaoli; Qu, Zhongquan; Xue, Zhike; Xiang, Yongyuan; Li, Hao

    2016-02-01

    We present a comprehensive study of the electric current related to the formation and eruption of active region filaments in NOAA AR 11884. The vertical current on the solar surface was investigated by using vector magnetograms (VMs) observed by HMI on board the Solar Dynamics Observatory. To obtain the electric current along the filament's axis, we reconstructed the magnetic fields above the photosphere by using nonlinear force-free field extrapolation based on photospheric VMs. Spatio-temporal evolutions of the vertical current on the photospheric surface and the horizontal current along the filament's axis were studied during the long-term evolution and eruption-related period, respectively. The results show that the vertical currents of the entire active region behaved with a decreasing trend and the magnetic fields also kept decreasing during the long-term evolution. For the eruption-related evolution, the mean transverse field strengths decreased before two eruptions and increased sharply after two eruptions in the vicinity of the polarity inversion lines underneath the filament. The related vertical current showed different behaviors in two of the eruptions. On the other hand, a very interesting feature was found: opposite horizontal currents with respect to the current of the filament's axis appeared and increased under the filament before the eruptions and disappeared after the eruptions. We suggest that these opposite currents were carried by the new flux emerging from the photosphere bottom and might be the trigger mechanism for these filament eruptions.

  7. Inhibition of volume-activated chloride currents in endothelial cells by chromones.

    PubMed Central

    Heinke, S.; Szücs, G.; Norris, A.; Droogmans, G.; Nilius, B.

    1995-01-01

    1. We have studied the effects of the reported chloride channel blocker, sodium cromoglycate, on volume-activated Cl- currents in endothelial cells from bovine pulmonary artery by means of the whole-cell patch clamp technique. Cl- currents were activated by challenging the cells with a hypotonic extracellular solution of 60% of the normal osmolarity. 2. Half maximal activation of the current at +95 mV occurred after exposure of the cells for 148 +/- 10 s (n = 6) to hypotonic solution (HTS). At the same membrane potential but in the presence of 100 microM sodium cromoglycate (disodium-1,3-bis (2'-carboxylate-chromone-5'-yloxy)-2-hydroxy-propane) activation was delayed (253 +/- 25 s, n = 6) and the maximal current amplitude was reduced to 63 +/- 7% of the control (n = 13). 3. In comparison, an equimolar concentration of NPPB (5-nitro-2(3-phenyl) propylamino-benzoic acid), another Cl- channel blocker, completely blocked the volume-activated current in less than 20 s. 4. Sodium cromoglycate, applied at the time when the HTS-induced current was completely activated, dose-dependently inhibited this current with a concentration for half maximal inhibition of 310 +/- 70 microM. Data for nedocromil sodium were not significantly different from those for sodium cromoglycate. 5. Sodium cromoglycate, loaded into the endothelial cells via the patch pipette in ruptured patches, resulted in a decline of the HTS activated current with a time course that was compatible with diffusion of the compound from the pipette into the cell.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8564197

  8. Construction and genetic selection of small transmembrane proteins that activate the human erythropoietin receptor.

    PubMed

    Cammett, Tobin J; Jun, Susan J; Cohen, Emily B; Barrera, Francisco N; Engelman, Donald M; Dimaio, Daniel

    2010-02-23

    This work describes a genetic approach to isolate small, artificial transmembrane (TM) proteins with biological activity. The bovine papillomavirus E5 protein is a dimeric, 44-amino acid TM protein that transforms cells by specifically binding and activating the platelet-derived growth factor beta receptor (PDGFbetaR). We used the E5 protein as a scaffold to construct a retrovirus library expressing approximately 500,000 unique 44-amino acid proteins with randomized TM domains. We screened this library to select small, dimeric TM proteins that were structurally unrelated to erythropoietin (EPO), but specifically activated the human EPO receptor (hEPOR). These proteins did not activate the murine EPOR or the PDGFbetaR. Genetic studies with one of these activators suggested that it interacted with the TM domain of the hEPOR. Furthermore, this TM activator supported erythroid differentiation of primary human hematopoietic progenitor cells in vitro in the absence of EPO. Thus, we have changed the specificity of a protein so that it no longer recognizes its natural target but, instead, modulates an entirely different protein. This represents a novel strategy to isolate small artificial proteins that affect diverse membrane proteins. We suggest the word "traptamer" for these transmembrane aptamers.

  9. Ocean Currents: Marine Science Activities for Grades 5-8. Teacher's Guide.

    ERIC Educational Resources Information Center

    Halversen, Catherine; Beals, Kevin; Strang, Craig

    This teacher's guide attempts to answer questions such as: What causes ocean currents? What impact do they have on Earth's environment? and How have they influenced human history? Seven innovative activities are provided in which students can gain fascinating insights into the earth as the ocean planet. Activities focus on how wind, temperature,…

  10. Ocean Currents: Marine Science Activities for Grades 5-8. Teacher's Guide.

    ERIC Educational Resources Information Center

    Halversen, Catherine; Beals, Kevin; Strang, Craig

    This teacher's guide attempts to answer questions such as: What causes ocean currents? What impact do they have on Earth's environment? and How have they influenced human history? Seven innovative activities are provided in which students can gain fascinating insights into the earth as the ocean planet. Activities focus on how wind, temperature,…

  11. 75 FR 32971 - Comment Request for Agency Information Collection Activities: Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-10

    ... Request for Agency Information Collection Activities: Extension of a Currently Approved Information...-day notice of information collection under review: Form ETA- 9033, Attestation by Employers using Alien Crewmembers for Longshore Activities at U.S. Ports; OMB Control No. 1205-0309. SUMMARY: The...

  12. Preliminary examination of the impacts of repository site characterization activities and facility construction and operation activities on Hanford air quality

    SciTech Connect

    Glantz, C.S.; Ramsdell, J.V.

    1986-04-01

    Air quality impacts that would result from site characterization activities and from the construction and operation of a high-level nuclear wste repository at Hanford are estimated using two simple atmospheric dispersion models, HANCHI and CHISHORT. Model results indicate that pollutant concentrations would not exceed ambient air quality standards at any point outside the Hanford fenceline or at any publicly accessible location within the Hanford Site. The increase in pollutant concentrations in nearby communities due to site activities would be minimal. HANCHI and CHISHORT are documented in the appendices of this document. Further study of the repository's impact on air quality will be conducted when more detailed project plans and work schedules are available.

  13. Large-scale performance and design for construction activity erosion control best management practices.

    PubMed

    Faucette, L B; Scholl, B; Beighley, R E; Governo, J

    2009-01-01

    The National Pollutant Discharge Elimination System (NPDES) Phase II requires construction activities to have erosion and sediment control best management practices (BMPs) designed and installed for site storm water management. Although BMPs are specified on storm water pollution prevention plans (SWPPPs) as part of the construction general permit (GP), there is little evidence in the research literature as to how BMPs perform or should be designed. The objectives of this study were to: (i) comparatively evaluate the performance of common construction activity erosion control BMPs under a standardized test method, (ii) evaluate the performance of compost erosion control blanket thickness, (iii) evaluate the performance of compost erosion control blankets (CECBs) on a variety of slope angles, and (iv) determine Universal Soil Loss Equation (USLE) cover management factors (C factors) for these BMPs to assist site designers and engineers. Twenty-three erosion control BMPs were evaluated using American Society of Testing and Materials (ASTM) D-6459, standard test method for determination of ECB performance in protecting hill slopes from rainfall induced erosion, on 4:1 (H:V), 3:1, and 2:1 slopes. Soil loss reduction for treatments exposed to 5 cm of rainfall on a 2:1 slope ranged from-7 to 99%. For rainfall exposure of 10 cm, treatment soil loss reduction ranged from 8 to 99%. The 2.5 and 5 cm CECBs significantly reduced erosion on slopes up to 2:1, while CECBs < 2.5 cm are not recommended on slopes >or= 4:1 when rainfall totals reach 5 cm. Based on the soil loss results, USLE C factors ranged from 0.01 to 0.9. These performance and design criteria should aid site planners and designers in decision-making processes.

  14. Efficient cross-modality cardiac four-dimensional active appearance model construction

    NASA Astrophysics Data System (ADS)

    Zhang, Honghai; Abiose, Ademola K.; Buettner, Elisabeth J.; Birrer, Emily K.; Sonka, Milan; Martins, James B.; Wahle, Andreas

    2009-02-01

    The efficiency of constructing an active appearance model (AAM) is limited by establishing the independent standard via time-consuming and tedious manual tracing. It is more challenging for 3D and 4D (3D+time) datasets as the smoothness of shape and motion is essential. In this paper, a three-stage pipeline is designed for efficient cross-modality model construction. It utilizes existing AAM and active shape model (ASM) of the left ventricle (LV) for magnetic resonance (MR) datasets to build 4D AAM of the LV for real-time 3D echocardiography (RT3DE) datasets. The first AAM fitting stage uses AAM for MR to fit valid shapes onto the intensity-transformed RT3DE data that resemble low-quality MR data. The fitting is implemented in a 3D phase-by-phase fashion to prevent introducing bias due to different motion patterns related to the two modalities and patient groups. The second global-scale editing stage adjusts fitted shapes by tuning modes of ASM for MR data. The third local-scale editing stage adjusts the fitted volumes at small local regions and produces the final accurate independent standard. By visual inspection, the AAM fitting stage successfully produces results that capture the LV motion - especially its base movement - within the cardiac cycle on 29 of the 32 RT3DE datasets tested. This multi-stage approach can reduce the human effort of the manual tracing by at least 50%. With the model built for a modality A available, this approach is generalizable to constructing the model of the same organ for any other modality B.

  15. Evidence-informed recommendations for constructing and disseminating messages supplementing the new Canadian Physical Activity Guidelines

    PubMed Central

    2013-01-01

    Background Few validated guidelines exist for developing messages in health promotion practice. In clinical practice, the Appraisal of Guidelines, Research, and Evaluation II (AGREE II) Instrument is the international gold standard for guideline assessment, development, and reporting. In a case study format, this paper describes the application of the AGREE II principles to guide the development of health promotion guidelines for constructing messages to supplement the new Canadian Physical Activity Guidelines (CPAG) released in 2011. Methods The AGREE II items were modified to suit the objectives of developing messages that (1) clarify key components of the new CPAG and (2) motivate Canadians to meet the CPAG. The adapted AGREE II Instrument was used as a systematic guide for the recommendation development process. Over a two-day meeting, five workgroups (one for each CPAG – child, youth, adult, older adult – and one overarching group) of five to six experts (including behavior change, messaging, and exercise physiology researchers, key stakeholders, and end users) reviewed and discussed evidence for creating and targeting messages to supplement the new CPAG. Recommendations were summarized and reviewed by workgroup experts. The recommendations were pilot tested among end users and then finalized by the workgroup. Results The AGREE II was a useful tool in guiding the development of evidence-based specific recommendations for constructing and disseminating messages that supplement and increase awareness of the new CPAG (child, youth, adults, and older adults). The process also led to the development of sample messages and provision of a rationale alongside the recommendations. Conclusions To our knowledge, these are the first set of evidence-informed recommendations for constructing and disseminating messages supplementing physical activity guidelines. This project also represents the first application of international standards for guideline development (i

  16. Glycine-activated currents are changed by coincident membrane depolarization in developing rat auditory brainstem neurones

    PubMed Central

    Backus, Kurt H; Deitmer, Joachim W; Friauf, Eckhard

    1998-01-01

    During early ontogeny, glycine receptors (GlyRs) exert depolarizing responses which may be of developmental relevance. We have used the gramicidin-perforated patch technique to elucidate the mechanism of glycine-activated currents in developing neurones of the rat lateral superior olive (LSO). When the holding potential was set to −60 mV, perforated-patch recordings revealed glycine-induced inward currents in 59%, outward currents in 5% and biphasic currents in 34% of the LSO neurones tested (n = 44). The biphasic currents were characterized by a transient outward phase which was followed by an inward phase. Ion substitution experiments showed that both Cl− and HCO3− contributed to the glycine- induced biphasic current responses. In the biphasic responses, the reversal potential of the glycine-induced current (Egly) depended on the response phase. A strong shift of Egly from a mean of −72 mV during the outward phase of the glycine response to a mean of −51 mV during the inward phase was observed, suggesting a shift of an ion gradient. When the membrane potential was depolarized, ‘tail’ currents were induced in the presence of glycine. An increased duration or amplitude of the evoked depolarizations resulted in a proportional enlargement of these tail currents, indicating that they were produced by a shift of an ion gradient. Since changes of the HCO3− gradient are negligible, because of the carbonic anhydrase activity, we suggest that these tail currents were caused by a shift of the Cl− gradient. We conclude that Cl− accumulates intracellularly during the activation of GlyRs and, consequently, Egly moves towards more positive values. Coincident depolarizing stimuli enhanced intracellular Cl− accumulation and the shift of Egly, thereby switching hyperpolarizing to depolarizing action. This change could assist in an activity-dependent strengthening and refinement of glycinergic synapses during the maturation of inhibitory connectivity. PMID

  17. An Optimal CDS Construction Algorithm with Activity Scheduling in Ad Hoc Networks.

    PubMed

    Penumalli, Chakradhar; Palanichamy, Yogesh

    2015-01-01

    A new energy efficient optimal Connected Dominating Set (CDS) algorithm with activity scheduling for mobile ad hoc networks (MANETs) is proposed. This algorithm achieves energy efficiency by minimizing the Broadcast Storm Problem [BSP] and at the same time considering the node's remaining energy. The Connected Dominating Set is widely used as a virtual backbone or spine in mobile ad hoc networks [MANETs] or Wireless Sensor Networks [WSN]. The CDS of a graph representing a network has a significant impact on an efficient design of routing protocol in wireless networks. Here the CDS is a distributed algorithm with activity scheduling based on unit disk graph [UDG]. The node's mobility and residual energy (RE) are considered as parameters in the construction of stable optimal energy efficient CDS. The performance is evaluated at various node densities, various transmission ranges, and mobility rates. The theoretical analysis and simulation results of this algorithm are also presented which yield better results.

  18. Metal-Ion-Triggered Exonuclease III Activity for the Construction of DNA Colorimetric Logic Gates.

    PubMed

    Gao, Wan; Zhang, Li; Liang, Ru-Ping; Qiu, Jian-Ding

    2015-10-19

    The logic system is obtained by using a series of double-stranded (ds) DNA templates with mismatched base pairs (T-T or C-C) and ion-modulated exonuclease III (Exo III) activity, in which the Exo III cofactors, Hg(2+) and Ag(+) ions, are used as inputs for the activation of the respective scission of Exo III based on the formation of T-Hg(2+) -T or C-Ag(+) -C base pairs. Additionally, two kinds of signal probes are utilized to transduce the logic operations. One is the two split G-rich DNA strands that are used to design the OR, AND, INHIBIT, and XOR gates, whereas the other is the self-assembled split G-quadruplex structure to construct NOR, NAND, IMPLICATION, and XNOR operations based on DNA hybridization and strand displacement. In the presence of hemin, the split G-quadruplex biocatalyzes the formation of a colored product, which is an output signal for the different logic gates. Thus, we have constructed a complete set of colorimetric DNA logic gates based on the Exo III and split G-quadruplex for the first time. In addition, we are able to effortlessly recognize the logic output signals by the naked eye and their simplicity and cost-effective design is the most apparent feature for the logic gates developed in this work. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Design and purification of active truncated phosphoinositide 3-kinase gamma protein constructs for structural studies.

    PubMed

    Vujičić Žagar, A; Scapozza, L; Vadas, O

    2017-07-01

    Phosphoinositide 3-kinase gamma (PI3Kγ) is a lipid kinase that plays a crucial role in cell migration, chemotaxis, oxidative burst and myocardial contractility. It is activated downstream of G protein-coupled receptors (GPCRs) and small GTPases of Ras superfamily. PI3Kγ is a heterodimer composed of a catalytic and a regulatory subunit that is expressed mostly in hematopoietic cells and in the heart. Although it has attracted a lot of attention because of its link with tumor inflammation and heart diseases, its regulation is still not fully understood. This can be attributed to the absence of high-resolution structural details of the PI3Kγ heterodimer. Here we describe the design and purification of PI3Kγ constructs where flexible loops in the regulatory subunit have been removed based on structural information obtained by hydrogen/deuterium exchange - mass spectrometry (HDX-MS). The soluble constructs retain both basal activity and sensitivity to GPCR stimulation, and are thus an optimal tool to further explore their regulation using a structure-based approach. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. [Sanitary-and-epidemiological support of town-planning activities at all stages of an investment-construction cycle].

    PubMed

    Khinziiaev, V I; Priadko, A L

    2009-01-01

    The paper provides evidence for a need for a systems approach to the sanitary-and-epidemiological support of construction projects at all stages of an investment-construction cycle, considers individual stages of work execution, and notes the increasing role of laboratory and instrumental studies and measurements at each stage. It is emphasized that sanitary-and-epidemiological support (or, in other words, sanitary-and-epidemiological audit) of a project (construction products) at all stages of an investment-construction cycle is an important and promising line in town-planning activities.

  1. Early and current physical activity: relationship with intima-media thickness and metabolic variables in adulthood

    PubMed Central

    Lima, Manoel C. S.; Barbosa, Maurício F.; Diniz, Tiego A.; Codogno, Jamile S.; Freitas, Ismael F.; Fernandes, Rômulo A.

    2014-01-01

    Background: It is unclear whether early physical activity has a greater influence on intima-media thickness and metabolic variables than current physical activity. Objective: To analyze the relationship between current and early physical activity, metabolic variables, and intima-media thickness measures in adults. Method: The sample was composed of 55 healthy subjects of both sexes (33 men and 22 women). Total body fat and trunk fat were estimated by dual-energy X-ray absorptiometry. Carotid and femoral intima-media thickness were measured using a Doppler ultrasound device. A 12-hour fasting blood sample collection was taken (fasting glucose and lipid profile). Early physical activity was assessed through face-to-face interview, and the current physical activity was assessed by pedometer (Digi-Walker Yamax, SW200), which was used for a period of seven days. Results: Current physical activity was negatively related to total cholesterol (rho=-0.31), while early physical activity was negatively related to triglycerides (rho=-0.42), total cholesterol (rho=-0.28), very low density lipoprotein (rho=-0.44), and carotid intima-media thickness (rho=-0.50). In the multivariate model, subjects engaged in sports activities during early life had lower values of very low density lipoprotein (b=-8.74 [b=-16.1; -1.47]) and carotid intima-media thickness (b=-0.17 [95%CI: -0.28; -0.05]). Conclusion: Early 95%CI physical activity has a significant influence on carotid intima-media thickness, regardless of the current physical activity. PMID:25372009

  2. Early and current physical activity: relationship with intima-media thickness and metabolic variables in adulthood.

    PubMed

    Lima, Manoel C S; Barbosa, Maurício F; Diniz, Tiego A; Codogno, Jamile S; Freitas Júnior, Ismael F; Fernandes, Rômulo A

    2014-08-29

    Background: It is unclear whether early physical activity has a greater influence on intima-media thickness and metabolic variables than current physical activity. Objective: To analyze the relationship between current and early physical activity, metabolic variables, and intima-media thickness measures in adults. Method: The sample was composed of 55 healthy subjects of both sexes (33 men and 22 women). Total body fat and trunk fat were estimated by dual-energy X-ray absorptiometry. Carotid and femoral intima-media thickness were measured using a Doppler ultrasound device. A 12-hour fasting blood sample collection was taken (fasting glucose and lipid profile). Early physical activity was assessed through face-to-face interview, and the current physical activity was assessed by pedometer (Digi-Walker Yamax, SW200), which was used for a period of seven days. Results: Current physical activity was negatively related to total cholesterol (rho=-0.31), while early physical activity was negatively related to triglycerides (rho=-0.42), total cholesterol (rho=-0.28), very low density lipoprotein (rho=-0.44), and carotid intima-media thickness (rho=-0.50). In the multivariate model, subjects engaged in sports activities during early life had lower values of very low density lipoprotein (b=-8.74 [b=-16.1; -1.47]) and carotid intima-media thickness (b=-0.17 [95%CI: -0.28; -0.05]). Conclusion: Early 95%CI physical activity has a significant influence on carotid intima-media thickness, regardless of the current physical activity.

  3. Early and current physical activity: relationship with intima-media thickness and metabolic variables in adulthood.

    PubMed

    Lima, Manoel C S; Barbosa, Maurício F; Diniz, Tiego A; Codogno, Jamile S; Freitas Júnior, Ismael F; Fernandes, Rômulo A

    2014-01-01

    It is unclear whether early physical activity has a greater influence on intima-media thickness and metabolic variables than current physical activity. To analyze the relationship between current and early physical activity, metabolic variables, and intima-media thickness measures in adults. The sample was composed of 55 healthy subjects of both sexes (33 men and 22 women). Total body fat and trunk fat were estimated by dual-energy X-ray absorptiometry. Carotid and femoral intima-media thickness were measured using a Doppler ultrasound device. A 12-hour fasting blood sample collection was taken (fasting glucose and lipid profile). Early physical activity was assessed through face-to-face interview, and the current physical activity was assessed by pedometer (Digi-Walker Yamax, SW200), which was used for a period of seven days. Current physical activity was negatively related to total cholesterol (rho=-0.31), while early physical activity was negatively related to triglycerides (rho=-0.42), total cholesterol (rho=-0.28), very low density lipoprotein (rho=-0.44), and carotid intima-media thickness (rho=-0.50). In the multivariate model, subjects engaged in sports activities during early life had lower values of very low density lipoprotein (b=-8.74 [b95%CI=-16.1; -1.47]) and carotid intima-media thickness (b=-0.17 [95%CI: -0.28; -0.05]). Early 95%CI physical activity has a significant influence on carotid intima-media thickness, regardless of the current physical activity.

  4. In-vitro activity of sparfloxacin in comparison with currently available antimicrobials against respiratory tract pathogens.

    PubMed

    Baquero, F; Cantón, R

    1996-05-01

    Bacterial resistance to antimicrobial agents is an ever-increasing problem. The in-vitro activity of sparfloxacin compared with that of currently available antimicrobial agents against pathogens implicated in respiratory tract infections is reviewed. Sparfloxacin is a fluoroquinolone active against both penicillin-susceptible and -resistant strains of Streptococcus pneumoniae. It is also active against many other respiratory tract pathogens and may be a suitable alternative for empirical therapy of community-acquired respiratory tract infections.

  5. Choline chloride activates time-dependent and time-independent K+ currents in dog atrial myocytes.

    PubMed

    Fermini, B; Nattel, S

    1994-01-01

    Using the whole cell configuration of the patch-clamp technique, we studied the effect of isotonic replacement of bath sodium chloride (NaCl) by choline chloride (ChCl) in dog atrial myocytes. Our results show that ChCl triggered 1) activation of a time-independent background current, characterized by a shift of the holding current in the outward direction at potentials positive to the K+ equilibrium potential (EK), and 2) activation of a time- and voltage-dependent outward current, following depolarizing voltage steps positive to EK. Because the choline-induced current obtained by depolarizing steps exhibited properties similar to the delayed rectifier K+ current (IK), we named it IKCh. The amplitude of IKCh was determined by extracellular ChCl concentration, and this current was generally undetectable in the absence of ChCl. IKCh was not activated by acetylcholine (0.001-1.0 mM) or carbachol (10 microM) and could not be recorded in the absence of ChCl or when external NaCl was replaced by sucrose or tetramethylammonium chloride. IKCh was inhibited by atropine (0.01-1.0 microM) but not by the M1 antagonist pirenzepine (up to 10 microM). This current was carried mainly by K+ and was inhibited by CsCl (120 mM, in the pipette) or barium (1 mM, in the bath). We conclude that in dog atrial myocytes, ChCl activates a background conductance comparable to ACh-dependent K+ current, together with a time-dependent K+ current showing properties similar to IK.

  6. EVOLUTION OF CURRENTS OF OPPOSITE SIGNS IN THE FLARE-PRODUCTIVE SOLAR ACTIVE REGION NOAA 10930

    SciTech Connect

    Ravindra, B.; Venkatakrishnan, P.; Tiwari, Sanjiv Kumar; Bhattacharyya, R. E-mail: pvk@prl.res.in E-mail: ramit@prl.res.in

    2011-10-10

    Analysis of a time series of high spatial resolution vector magnetograms of the active region NOAA 10930 available from the Solar Optical Telescope SpectroPolarimeter on board Hinode revealed that there is a mixture of upward and downward currents in the two footpoints of an emerging flux rope. The flux emergence rate is almost the same in both the polarities. We observe that along with an increase in magnetic flux, the net current in each polarity increases initially for about three days after which it decreases. This net current is characterized by having exactly opposite signs in each polarity while its magnitude remains almost the same most of the time. The decrease of the net current in both the polarities is due to the increase of current having a sign opposite to that of the net current. The dominant current, with the same sign as the net current, is seen to increase first and then decreases during the major X-class flares. Evolution of non-dominant current appears to be a necessary condition for flare initiation. The above observations can be plausibly explained in terms of the superposition of two different force-free states resulting in a non-zero Lorentz force in the corona. This Lorentz force then pushes the coronal plasma and might facilitate the magnetic reconnection required for flares. Also, the evolution of the net current is found to follow the evolution of magnetic shear at the polarity inversion line.

  7. Niflumic acid reduces the hyperpolarization-activated current (I(h)) in rod photoreceptor cells.

    PubMed

    Satoh, T O; Yamada, M

    2001-08-01

    We examined the effects of niflumic acid (NFA), a chloride channel blocker, on the hyperpolarization-activated current (I(h)) in newt rod photoreceptors. At 100 microM, NFA delayed the activation of I(h) induced by hyperpolarizing voltage pulses to -83 mV from a holding potential of -43 mV, and reduced the steady-state current. However, reduction by NFA was weakened when I(h) was activated by hyperpolarizing steps to -123 mV, suggesting that these effects were voltage-dependent. The suppressive effects of NFA on I(h) were accompanied by a negative shift in activation voltage. NFA also delayed the relaxation of I(h) tail currents, showing that this drug also inhibited deactivation of the current. The reversal potential and the fully activated conductance were not affected. These observations suggest that NFA reduces I(h) by modifying the gating kinetics of the underlying channels. The suppressive actions of NFA remained when intracellular Ca2+ was strongly chelated, and the failure of suppression by NFA in inside-out patches suggests that the agent may act on the I(h) channel from the extracellular side. These results, obtained in rod photoreceptors, are consistent with similar effects of NFA on I(f) in cardiac myocytes, suggesting that both currents share similar pharmacological properties.

  8. Characterization of the maitotoxin-activated cationic current from human skin fibroblasts

    PubMed Central

    Martínez-François, Juan Ramón; Morales-Tlalpan, Verónica; Vaca, Luis

    2002-01-01

    The maitotoxin (MTX)-induced cationic current (Imtx) from human skin fibroblasts was characterized using the patch-clamp technique in whole-cell configuration. Under resting conditions (absence of MTX), the main current observed is produced by an outwardly rectifying K+ channel which is inhibited by 1 mm TEA. The current reversal potential was −86 mV (n = 12). MTX (500 pm) activated a current with a linear current–voltage relationship and a reversal potential of −10 mV (n = 10). Replacing the extracellular Na+ and K+ with N-methyl-d-glucamine (NMDG) caused a shift of the reversal potential to a value below −100 mV, indicating that Na+ and K+, but not NMDG, carry Imtx. Further ion selectivity experiments showed that Ca2+ carries Imtx also. The resulting permeability sequence obtained with the Goldman–Hodgkin–Katz equation yielded Na+ (1) ≈ K+ (1) > Ca2+ (0.87). The Imtx activation time course reflected the changes in intracellular Ca2+ and Na+ measured with the fluorescent indicators fura-2 and SBFI, respectively, suggesting that the activation of Imtx brings about an increment in intracellular Ca2+ and Na+. Reducing the extracellular Ca2+ concentration below 1.8 mm prevented the activation of Imtx and the increment in intracellular Na+ induced by MTX. Mn2+ and Mg2+ could not replace Ca2+, but Ba2+ could replace Ca2+. MTX activation of current in 10 mm Ba2+ was approximately 50 % of that induced in the presence of 1.8 mm Ca2+. When 5 mm of the Ca2+ chelator BAPTA was included in the patch pipette, MTX either failed to activate the current or induced a small current (less than 15 % of the control), indicating that intracellular Ca2+ is also required for the activation of Imtx. Intracellular Ba2+ can replace Ca2+ as an activator of Imtx. However, in the presence of 10 mm Ba2+ the activation by MTX of the current was 50 % less than the activation with nm concentrations of free intracellular Ca2+. PMID:11773318

  9. Disorder prediction-based construct optimization improves activity and catalytic efficiency of Bacillus naganoensis pullulanase

    PubMed Central

    Wang, Xinye; Nie, Yao; Mu, Xiaoqing; Xu, Yan; Xiao, Rong

    2016-01-01

    Pullulanase is a well-known starch-debranching enzyme. However, the production level of pullulanase is yet low in both wide-type strains and heterologous expression systems. We predicted the disorder propensities of Bacillus naganoensis pullulanase (PUL) using the bioinformatics tool, Disorder Prediction Meta-Server. On the basis of disorder prediction, eight constructs, including PULΔN5, PULΔN22, PULΔN45, PULΔN64, PULΔN78 and PULΔN106 by deleting the first 5, 22, 45, 64, 78 and 106 residues from the N-terminus, and PULΔC9 and PULΔC36 by deleting the last 9 and 36 residues from the C-terminus, were cloned into the recombinant expression vector pET-28a-PelB and auto-induced in Escherichia coli BL21 (DE3) cells. All constructs were evaluated in production level, specific activities and kinetic parameters. Both PULΔN5 and PULΔN106 gave higher production levels of protein than the wide type and displayed increased specific activities. Kinetic studies showed that substrate affinities of the mutants were improved in various degrees and the catalytic efficiency of PULΔN5, PULΔN45, PULΔN78, PULΔN106 and PULΔC9 were enhanced. However, the truncated mutations did not change the advantageous properties of the enzyme involving optimum temperature and pH for further application. Therefore, Disorder prediction-based truncation would be helpful to efficiently improve the enzyme activity and catalytic efficiency. PMID:27091115

  10. Erosion Control of Scour during Construction; Report 3. Experimental Measurements of Refraction, Diffraction, and Current Patterns Near Jetties.

    DTIC Science & Technology

    1980-09-01

    predict the probable magnitude of (Continued) DD vi’Ra 03 1wom or INov OM @ISDETR Unclassified S.CUm TY CLAS-.lCATIO OF THIS PAS.. (..m 0. Yw...transport of the bottom material at the particular site. The purpose of this study was to obtain detailed and precise experimental data regarding wave...currents. This removal of material from around structures is often not compensated by an influx of additional material ; the result is scour, or

  11. FCCP depolarizes plasma membrane potential by activating proton and Na+ currents in bovine aortic endothelial cells.

    PubMed

    Park, Kyu-Sang; Jo, Inho; Pak, Kim; Bae, Sung-Won; Rhim, Hyewhon; Suh, Suk-Hyo; Park, Jin; Zhu, Hong; So, Insuk; Kim, Ki Whan

    2002-01-01

    We investigated the effects of carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP), a protonophore and uncoupler of mitochondrial oxidative phosphorylation in mitochondria, on plasma membrane potential and ionic currents in bovine aortic endothelial cells (BAECs). The membrane potential and ionic currents of BAECs were recorded using the patch-clamp technique in current-clamp and voltage-clamp modes, respectively. FCCP activated ionic currents and depolarized the plasma membrane potential in a dose-dependent manner. Neither the removal of extracellular Ca2+ nor pretreatment with BAPTA/AM affected the FCCP-induced currents, implying that the currents are not associated with the FCCP-induced intracellular [Ca2+]i increase. FCCP-induced currents were significantly influenced by the changes in extracellular or intracellular pH; the increased proton gradient produced by lowering the extracellular pH or intracellular alkalinization augmented the changes in membrane potential and ionic currents caused by FCCP. FCCP-induced currents were significantly reduced under extracellular Na+-free conditions. The reversal potentials of FCCP-induced currents under Na+-free conditions were well fitted to the calculated equilibrium potential for protons. Interestingly, FCCP-induced Na+ transport (subtracted currents, I(control)- I(Na+-free) was closely dependent on extracellular pH, whereas FCCP-induced H+transport was not significantly affected by the absence of Na+. These results suggest that the FCCP-induced ionic currents and depolarization, which are strongly dependent on the plasmalemmal proton gradient, are likely to be mediated by both H+ and Na+ currents across the plasma membrane. The relationship between H+ and Na+ transport still needs to be determined.

  12. Paralleling power MOSFETs in their active region: Extended range of passively forced current sharing

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    1989-01-01

    A simple passive circuit that improves current balance in parallelled power MOSFETs that are not precisely matched and that are operated in their active region from a common gate drive are exhibited. A nonlinear circuit consisting of diodes and resistors generates the differential gate potential required to correct for unbalance while maintaining low losses over a range of current. Also application of a thin tape wound magnetic core to effect dynamic current balance is reviewed, and a simple theory is presented showing that for operation in the active region the branch currents tend to revert to their normal unbalanced values even if the core is not driven into saturation. Results of several comparative experiments are given.

  13. Current and maintained health-enhancing physical activity in rheumatoid arthritis: a cross-sectional study.

    PubMed

    Demmelmaier, Ingrid; Bergman, Patrick; Nordgren, Birgitta; Jensen, Irene; Opava, Christina H

    2013-07-01

    To describe and identify the explanatory factors of variation in current and maintained health-enhancing physical activity (HEPA) in persons with rheumatoid arthritis (RA). In this cross-sectional study, current HEPA was assessed with the International Physical Activity Questionnaire and maintained HEPA with the Exercise Stage Assessment Instrument, the latter explicitly focusing on both aerobic physical activity and muscle strength training. Sociodemographic, disease-related, and psychosocial data were retrieved from the Swedish Rheumatology Quality (SRQ) registers and a postal questionnaire. The explained variations in the respective HEPA behaviors were analyzed with logistic regression. In all, 3,152 (58.5%) of 5,391 persons identified as eligible from the SRQ registers responded to the questionnaire. Current HEPA was reported by 69%, and maintained HEPA by 11% of the respondents. The most salient and consistent factors explaining variation in both current and maintained HEPA were self-efficacy, social support, and outcome expectations related to physical activity. To our knowledge, this is the first study exploring maintained physical activity in a large well-defined sample of persons with RA. Our results indicate that a minority perform maintained HEPA, including both aerobic physical activity and muscle strength training, and that psychosocial factors are the most salient and consistent in the explanation of HEPA variation. Copyright © 2013 by the American College of Rheumatology.

  14. Three-dimensional ventricular activation imaging by means of equivalent current source modeling and estimation.

    PubMed

    Liu, Z; Liu, C; He, B

    2006-01-01

    This paper presents a novel electrocardiographic inverse approach for imaging the 3-D ventricular activation sequence based on the modeling and estimation of the equivalent current density throughout the entire myocardial volume. The spatio-temporal coherence of the ventricular excitation process is utilized to derive the activation time from the estimated time course of the equivalent current density. At each time instant during the period of ventricular activation, the distributed equivalent current density is noninvasively estimated from body surface potential maps (BSPM) using a weighted minimum norm approach with a spatio-temporal regularization strategy based on the singular value decomposition of the BSPMs. The activation time at any given location within the ventricular myocardium is determined as the time point with the maximum local current density estimate. Computer simulation has been performed to evaluate the capability of this approach to image the 3-D ventricular activation sequence initiated from a single pacing site in a physiologically realistic cellular automaton heart model. The simulation results demonstrate that the simulated "true" activation sequence can be accurately reconstructed with an average correlation coefficient of 0.90, relative error of 0.19, and the origin of ventricular excitation can be localized with an average localization error of 5.5 mm for 12 different pacing sites distributed throughout the ventricles.

  15. Activation of muscarinic K+ current in guinea-pig atrial myocytes by a serum factor.

    PubMed Central

    Banach, K; Hüser, J; Lipp, P; Wellner, M C; Pott, L

    1993-01-01

    1. Atrial myocytes obtained by enzymatic perfusion of hearts from adult guinea-pigs and cultured for 0-14 days were studied using the whole-cell voltage-clamp technique. 2. Superfusion of the myocytes with diluted sera (1:100 to 1:10,000) from different species (human, horse, guinea-pig) evoked an inward rectifying K+ current. The voltage-dependent properties of this current were identical to those of the K+ current activated by acetylcholine (IK(ACh)). Current density in the presence of horse serum (1:100) approximately corresponded to the non-desensitizing fraction of IK(ACh) during superfusion with 1-2 x 10(-6) M ACh. 3. During a maximal serum-evoked current, application of ACh (10(-6) M) failed to evoke additional K+ current. After switching superfusion from serum-containing to serum-free solution, the K+ current decayed 1-2 orders of magnitude slower than ACh-activated IK(ACh). During the decay of the serum-evoked current, a proportional increase in responsiveness to ACh was recorded. During submaximal activation of K+ current by serum, a saturating concentration of ACh resulted in a total current that was identical to the current evoked by ACh alone minus the desensitizing component. Thus, activation of K+ current by serum caused desensitization of IK(ACh). From these results it is concluded that sera contain a factor that activates the same population of K+ channels as ACh. 4. Irreversible activation of IK(ACh) by ACh in myocytes dialysed with the GTP-analogue GTP-gamma-S abolished sensitivity to serum and vice versa. 5. The effect of serum was not modified by atropine (10(-6) M) which completely blocked the response to 2 x 10(-6) M ACh. Furthermore, theophylline (1 mM), which completely inhibited IK(ACh) activation by adenosine (100 microM), failed to inhibit the effect of serum. Thus, neither muscarinic nor purinergic (A1) receptors are involved. 6. The peptide somatostatin (10(-6) M) and the alpha 1-agonist phenylephrine (1 microM) which previously have

  16. The effect of a self-constructed material on children's physical activity during recess.

    PubMed

    Méndez-Giménez, Antonio; Cecchini, José-Antonio; Fernández-Río, Javier

    2017-06-26

    To analyze whether an intervention supported by free play with a self-constructed material increases the level of physical activity of students during recess. The participants were 166 children of third to sixth grade, between nine and 12 years old (average = 10.64; SS = 1.13). An experimental project was conducted with pre-test and post-test measurement, and a control group. Experimental group participants built cardboard paddles (third and fourth) and flying rings (fifth and sixth), a material they used freely for one week during recess. ActiGraph-GT3X accelerometers were used to measure physical activity. An ANOVA of repeated measures was used to find differences between groups and genders. Significant intervention effects were found in the analyzed variables: sedentary activity (F = 38.19; p < 0.01), light (F = 76.56; p < 0.01), moderate (F = 27.44; p < 0.01), vigorous (F = 61.55; p < 0.01), and moderate and vigorous (F = 68.76; p < 0.01). Significant gender differences were shown (time × group × gender) for moderate (F = 6.58; p < 0.05) and vigorous (F = 5.51; p < 0.05) activity. The self-constructed material is effective to increase the physical activity levels of children during recess; it decreases sedentary activity and light physical activity and increases the time devoted to moderate physical activity and vigorous physical activity, both in boys and in girls. The boys had an increase in vigorous physical activity and the girls in moderate physical activity. Due to its low cost, this strategy is recommended for administrators and teachers to increase the physical activity of children during recess. Analizar si una intervención basada en el juego libre con material autoconstruido aumenta el nivel de actividad física de los escolares durante el recreo. Participaron 166 niños de tercero a sexto de educación primaria, de entre nueve y 12 años de edad (media = 10,64; DE = 1,13). Se realizó un diseño experimental con medidas pretest y postest, y un

  17. A Palladium-Binding Deltarhodopsin for Light-Activated Conversion of Protonic to Electronic Currents.

    PubMed

    Soto-Rodríguez, Jessica; Hemmatian, Zahra; Josberger, Erik E; Rolandi, Marco; Baneyx, François

    2016-08-01

    Fusion of a palladium-binding peptide to an archaeal rhodopsin promotes intimate integration of the lipid-embedded membrane protein with a palladium hydride protonic contact. Devices fabricated with the palladium-binding deltarhodopsin enable light-activated conversion of protonic currents to electronic currents with on/off responses complete in seconds and a nearly tenfold increase in electrical signal relative to those made with the wild-type protein.

  18. Extended Sugawara construction for the superalgebras SU(M+1||N+1). I. Free-field representation and bosonization of super Kac-Moody currents

    NASA Astrophysics Data System (ADS)

    Bouwknegt, P.; Ceresole, A.; McCarthy, J. G.; van Nieuwenhuizen, P.

    1989-05-01

    In a series of two papers we will generalize the extended Sugawara construction to the superalgebra SU(M+1||N+1). This first part contains ground work which we need to construct examples of closed extended algebras. We develop the tensor analysis for contractions of super d and f symbols, and we present a free-field representation of the super Kac-Moody currents at level 1 in terms of spin-0 fields. This is obtained from the standard spin-1/2 conjugate free-field representation by bosonization. Because of the mixed statistics, some of these conjugate pairs are of the βγ type-similar to the superghosts appearing in Neveu-Schwarz-Ramond strings. The partial check on bosonization we carry out, in which we compare the torus partition functions before and after bosonization, is also of interest in that context.

  19. Development of the Oxford Participation and Activities Questionnaire: constructing an item pool

    PubMed Central

    Kelly, Laura; Jenkinson, Crispin; Dummett, Sarah; Dawson, Jill; Fitzpatrick, Ray; Morley, David

    2015-01-01

    Purpose The Oxford Participation and Activities Questionnaire is a patient-reported outcome measure in development that is grounded on the World Health Organization International Classification of Functioning, Disability, and Health (ICF). The study reported here aimed to inform and generate an item pool for the new measure, which is specifically designed for the assessment of participation and activity in patients experiencing a range of health conditions. Methods Items were informed through in-depth interviews conducted with 37 participants spanning a range of conditions. Interviews aimed to identify how their condition impacted their ability to participate in meaningful activities. Conditions included arthritis, cancer, chronic back pain, diabetes, motor neuron disease, multiple sclerosis, Parkinson’s disease, and spinal cord injury. Transcripts were analyzed using the framework method. Statements relating to ICF themes were recast as questionnaire items and shown for review to an expert panel. Cognitive debrief interviews (n=13) were used to assess items for face and content validity. Results ICF themes relevant to activities and participation in everyday life were explored, and a total of 222 items formed the initial item pool. This item pool was refined by the research team and 28 generic items were mapped onto all nine chapters of the ICF construct, detailing activity and participation. Cognitive interviewing confirmed the questionnaire instructions, items, and response options were acceptable to participants. Conclusion Using a clear conceptual basis to inform item generation, 28 items have been identified as suitable to undergo further psychometric testing. A large-scale postal survey will follow in order to refine the instrument further and to assess its psychometric properties. The final instrument is intended for use in clinical trials and interventions targeted at maintaining or improving activity and participation. PMID:26056503

  20. Pregnant women's perceptions of weight gain, physical activity, and nutrition using Theory of Planned Behavior constructs.

    PubMed

    Whitaker, Kara M; Wilcox, Sara; Liu, Jihong; Blair, Steven N; Pate, Russell R

    2016-02-01

    A better understanding of women's perceptions of weight gain and related behaviors during pregnancy is necessary to inform behavioral interventions. We used the Theory of Planned Behavior (TPB) to examine pregnant women's perceptions and intentions toward weight gain, physical activity (PA), and nutrition using a mixed methods study design. Women between 20 and 30 weeks gestation (n = 189) were recruited to complete an Internet-based survey. Salient beliefs toward weight gain, PA, and nutrition were captured through open-ended responses and content analyzed into themes. TPB constructs (attitude, subjective norm, perceived behavioral control, intentions) were examined using Pearson correlations and hierarchical linear regression models. Salient beliefs were consistent with the existing literature in non-pregnant populations, with the addition of many pregnancy-specific beliefs. TPB constructs accounted for 23-39 % of the variance in weight gain, PA, and nutrition intentions, and made varying contributions across outcomes. The TPB is a useful framework for examining women's weight-related intentions during pregnancy. Study implications for intervention development are discussed.

  1. Estimating NOA Health Risks from Selected Construction Activities at the Calaveras Dam Replacement Project (CDRP)

    NASA Astrophysics Data System (ADS)

    Hernandez, D. W.

    2012-12-01

    The CDRP is a major construction project involving up to 400 workers using heavy earth moving equipment, blasting, drilling, rock crushing, and other techniques designed to move 7 million yards of earth. Much of this material is composed of serpentinite, blueschist, and other rocks that contain chrysotile, crocidolite, actinolite, tremolite, and Libby-class amphiboles. To date, over 1,000 personal, work area, and emission inventory related samples have been collected and analyzed by NIOSH 7400, NIOSH 7402, and CARB-AHERA methodology. Data indicate that various CDRP construction activities have the potential to generate significant mineral fibers and structures that could represent elevated on site and off site health risks. This presentation will review the Contractors air monitoring program for this major project, followed by a discussion of predictive methods to evaluate potential onsite and offsite risks. Ultimately, the data are used for planning control strategies designed to achieve a Project Action Level of 0.01 f/cc (one tenth the Cal/OSHA PEL) and risk-based offsite target levels.

  2. Effects of SDPNFLRF-amide (PF1) on voltage-activated currents in Ascaris suum muscle

    PubMed Central

    Verma, S.; Robertson, A.P.; Martin, R.J.

    2008-01-01

    Helminth infections are of significant concern in veterinary and human medicine. The drugs available for chemotherapy are limited in number and the extensive use of these drugs has led to the development of resistance in parasites of animals and humans (Geerts and Gryseels, 2000; Kaplan, 2004; Osei-Atweneboana et al., 2007). The cyclooctadepsipeptide, emodepside, belongs to a new class of anthelmintic that has been released for animal use in recent years. Emodepside has been proposed to mimic the effects of the neuropeptide PF1 on membrane hyperpolarization and membrane conductance (Willson et al., 2003). We investigated the effects of PF1 on voltage-activated currents in Ascaris suum muscle cells. The whole cell voltage-clamp technique was employed to study these currents. Here we report two types of voltage-activated inward calcium currents: transient peak (Ipeak) and a steady-state (Iss). We found that 1 μM PF1 inhibited the two calcium currents. The Ipeak decreased from −146 nA to −99 nA (P = 0.0007) and the Iss decreased from −45 nA to −12 nA (P = 0.002). We also found that PF1 in the presence of calcium increased the voltage-activated outward potassium current (from 521 nA to 628 nA (P = 0.004)). The effect on the potassium current was abolished when calcium was removed and replaced with cobalt; it was also reduced at a higher concentration of PF1 (10 μM). These studies demonstrate a mechanism by which PF1 decreases the excitability of the neuromuscular system by modulating calcium currents in nematodes. PF1 inhibits voltage-activated calcium currents and potentiates the voltage-activated calcium-dependent potassium current. The effect on a calcium-activated-potassium channel appears to be common to both PF1 and emodepside (Guest et al., 2007). It will be of interest to investigate the actions of emodepside on calcium currents to further elucidate the mechanism of action. PMID:18760280

  3. Characterization of two distinct depolarization-activated K+ currents in isolated adult rat ventricular myocytes

    PubMed Central

    1991-01-01

    Depolarization-activated outward K+ currents in isolated adult rat ventricular myocytes were characterized using the whole-cell variation of the patch-clamp recording technique. During brief depolarizations to potentials positive to -40 mV, Ca(2+)-independent outward K+ currents in these cells rise to a transient peak, followed by a slower decay to an apparent plateau. The analyses completed here reveal that the observed outward current waveforms result from the activation of two kinetically distinct voltage-dependent K+ currents: one that activates and inactivates rapidly, and one that activates and inactivates slowly, on membrane depolarization. These currents are referred to here as Ito (transient outward) and IK (delayed rectifier), respectively, because their properties are similar (although not identical) to these K+ current types in other cells. Although the voltage dependences of Ito and IK activation are similar, Ito activates approximately 10-fold and inactivates approximately 30-fold more rapidly than IK at all test potentials. In the composite current waveforms measured during brief depolarizations, therefore, the peak current predominantly reflects Ito, whereas IK is the primary determinant of the plateau. There are also marked differences in the voltage dependences of steady-state inactivation of these two K+ currents: IK undergoes steady-state inactivation at all potentials positive to -120 mV, and is 50% inactivated at -69 mV; Ito, in contrast, is insensitive to steady-state inactivation at membrane potentials negative to -50 mV. In addition, Ito recovers from steady-state inactivation faster than IK: at -90 mV, for example, approximately 70% recovery from the inactivation produced at -20 mV is observed within 20 ms for Ito; IK recovers approximately 25-fold more slowly. The pharmacological properties of Ito and IK are also distinct: 4-aminopyridine preferentially attenuates Ito, and tetraethylammonium suppresses predominantly IK. The voltage- and

  4. Effects of SDPNFLRF-amide (PF1) on voltage-activated currents in Ascaris suum muscle.

    PubMed

    Verma, S; Robertson, A P; Martin, R J

    2009-02-01

    Helminth infections are of significant concern in veterinary and human medicine. The drugs available for chemotherapy are limited in number and the extensive use of these drugs has led to the development of resistance in parasites of animals and humans (Geerts and Gryseels, 2000; Kaplan, 2004; Osei-Atweneboana et al., 2007). The cyclooctadepsipeptide, emodepside, belongs to a new class of anthelmintic that has been released for animal use in recent years. Emodepside has been proposed to mimic the effects of the neuropeptide PF1 on membrane hyperpolarization and membrane conductance (Willson et al., 2003). We investigated the effects of PF1 on voltage-activated currents in Ascaris suum muscle cells. The whole cell voltage-clamp technique was employed to study these currents. Here we report two types of voltage-activated inward calcium currents: transient peak (I(peak)) and a steady-state (I(ss)). We found that 1microM PF1 inhibited the two calcium currents. The I(peak) decreased from -146nA to -99nA (P=0.0007) and the I(ss) decreased from -45nA to -12nA (P=0.002). We also found that PF1 in the presence of calcium increased the voltage-activated outward potassium current (from 521nA to 628nA (P=0.004)). The effect on the potassium current was abolished when calcium was removed and replaced with cobalt; it was also reduced at a higher concentration of PF1 (10microM). These studies demonstrate a mechanism by which PF1 decreases the excitability of the neuromuscular system by modulating calcium currents in nematodes. PF1 inhibits voltage-activated calcium currents and potentiates the voltage-activated calcium-dependent potassium current. The effect on a calcium-activated-potassium channel appears to be common to both PF1 and emodepside (Guest et al., 2007). It will be of interest to investigate the actions of emodepside on calcium currents to further elucidate the mechanism of action.

  5. Co-Construction in Korean Interaction

    ERIC Educational Resources Information Center

    Ju, Hee

    2011-01-01

    This dissertation explores co-construction of a situated activity in a current unit by mainly focusing on hearers' actions. The "co-construction" involves a process of interaction in which speakers and hearers jointly construct the form and the meaning of ongoing utterances even when they disagree with each other (Jacoby & Ochs,…

  6. Co-Construction in Korean Interaction

    ERIC Educational Resources Information Center

    Ju, Hee

    2011-01-01

    This dissertation explores co-construction of a situated activity in a current unit by mainly focusing on hearers' actions. The "co-construction" involves a process of interaction in which speakers and hearers jointly construct the form and the meaning of ongoing utterances even when they disagree with each other (Jacoby & Ochs,…

  7. Current steering to activate targeted neural pathways during deep brain stimulation of the subthalamic region

    PubMed Central

    Chaturvedi, Ashutosh; Foutz, Thomas J.; McIntyre, Cameron C.

    2012-01-01

    Deep brain stimulation (DBS) has steadily evolved into an established surgical therapy for numerous neurological disorders, most notably Parkinson’s disease (PD). Traditional DBS technology relies on voltage-controlled stimulation with a single source; however, recent engineering advances are providing current-controlled devices with multiple independent sources. These new stimulators deliver constant current to the brain tissue, irrespective of impedance changes that occur around the electrode, and enable more specific steering of current towards targeted regions of interest. In this study, we examined the impact of current steering between multiple electrode contacts to directly activate three distinct neural populations in the subthalamic region commonly stimulated for the treatment of PD: projection neurons of the subthalamic nucleus (STN), globus pallidus internus (GPi) fibers of the lenticular fasiculus, and internal capsule (IC) fibers of passage. We used three-dimensional finite element electric field models, along with detailed multi-compartment cable models of the three neural populations to determine their activations using a wide range of stimulation parameter settings. Our results indicate that selective activation of neural populations largely depends on the location of the active electrode(s). Greater activation of the GPi and STN populations (without activating any side-effect related IC fibers) was achieved by current steering with multiple independent sources, compared to a single current source. Despite this potential advantage, it remains to be seen if these theoretical predictions result in a measurable clinical effect that outweighs the added complexity of the expanded stimulation parameter search space generated by the more flexible technology. PMID:22277548

  8. CURRENT HELICITY OF ACTIVE REGIONS AS A TRACER OF LARGE-SCALE SOLAR MAGNETIC HELICITY

    SciTech Connect

    Zhang, H.; Gao, Y.; Xu, H.; Moss, D.; Kleeorin, N.; Rogachevskii, I.; Kuzanyan, K.; Sokoloff, D.

    2012-05-20

    We demonstrate that the current helicity observed in solar active regions traces the magnetic helicity of the large-scale dynamo generated field. We use an advanced two-dimensional mean-field dynamo model with dynamo saturation based on the evolution of the magnetic helicity and algebraic quenching. For comparison, we also studied a more basic two-dimensional mean-field dynamo model with simple algebraic alpha-quenching only. Using these numerical models we obtained butterfly diagrams both for the small-scale current helicity and also for the large-scale magnetic helicity, and compared them with the butterfly diagram for the current helicity in active regions obtained from observations. This comparison shows that the current helicity of active regions, as estimated by -A {center_dot} B evaluated at the depth from which the active region arises, resembles the observational data much better than the small-scale current helicity calculated directly from the helicity evolution equation. Here B and A are, respectively, the dynamo generated mean magnetic field and its vector potential. A theoretical interpretation of these results is given.

  9. Reduction, Analysis, and Properties of Electric Current Systems in Solar Active Regions

    NASA Technical Reports Server (NTRS)

    Gary, G. Allen; Demoulin, Pascal

    1995-01-01

    The specific attraction and, in large part, the significance of solar vector magnetograms lie in the fact that they give the most important data on the electric currents and the nonpotentiality of active regions. Using the vector magnetograms from the Marshall Space Flight Center (MSFC), we employ a unique technique in the area of data analysis for resolving the 180 degree ambiguity in order to calculate the spatial structure of the vertical electric current density. The 180 degree ambiguity is resolved by applying concepts from the nonlinear multivariable optimization theory. The technique is shown to be of particular importance in very nonpotential active regions. The characterization of the vertical electric current density for a set of vector magnetograms using this method then gives the spatial scale, locations, and magnitude of these current systems. The method, which employs an intermediate parametric function which covers the magnetogram and which defines the local "preferred" direction, minimizes a specific functional of the observed transverse magnetic field. The specific functional that is successful is the integral of the square of the vertical current density. We find that the vertical electric current densities have common characteristics for the extended bipolar beta gamma delta-regions studied. The largest current systems have j(sub z)'s which maximizes around 30 mA per square meter and have a linear decreasing distribution to a diameter of 30 Mm.

  10. Reduction, analysis, and properties of electric current systems in solar active regions

    NASA Technical Reports Server (NTRS)

    Gary, G. Allen; Demoulin, Pascal

    1995-01-01

    The specific attraction and, in large part, the significance of solar magnetograms lie in the fact that they give the most important data on the electric currents and the nonpotentiality of active regions. Using the vector magnetograms from the Marshall Space Flight Center (MSFC), we employ a unique technique in the area of data analysis for resolving the 180 deg ambiguity in order to calculate the spatial structure of the vertical electric current density. The 180 deg ambiguity is resolved by applying concepts from the nonlinear multivariable optimization theory. The technique is shown to be of particular importance in very nonpotential active regions. The characterization of the vertical electric current density for a set of vector magnetograms using this method then gives the spatial scale, locations, and magnitude of these current systems. The method, which employs an intermediate parametric function which covers the magnetogram and which defines the local `preferred' direction, minimizes a specific functional of the observed transverse magnetic field. The specific functional that is successful is the integral of the square of the vertical current density. We find that the vertical electric current densities have common characteristics for the extended bipolar (beta) (gamma) (delta)-regions studied. The largest current systems have j(sub z)'s which maximizes around 30 mA/sq m and have a linear decreasing distribution to a diameter of 30 Mn.

  11. HBT-EP Program: MHD Dynamics and Active Control through 3D Fields and Currents

    NASA Astrophysics Data System (ADS)

    Navratil, G. A.; Abler, M. C.; Bialek, J.; Brooks, J. W.; Byrne, P. J.; Desanto, S.; Hughes, P. E.; Levesque, J. P.; Mauel, M. E.; Rhodes, D. J.; Hansen, C. J.

    2016-10-01

    The HBT-EP active mode control research program aims to: (i) advance understanding of the effects of 3D shaping on advanced tokamak fusion performance, (ii) resolve important MHD issues associated with disruptions, and (iii) measure and mitigate the effects of 3D scrape-off layer (SOL) currents through active and passive control of the plasma edge and conducting boundary structures. A GPU-based low latency control system uses 96 inputs and 64 outputs to control the plasma boundary. An in-vessel adjustable ferritic wall is used to study ferritic RWMs with increased growth rates, RMP response, and disruptivity. A quasi-linear sharp-boundary model is developed to study effects of toroidal curvature and plasma shaping on beta limits with resistive plasmas and walls. Measurement of currents between vessel sections reveals currents running from the plasma to the wall during wall-touching kink modes and disruptions. Asymmetries in plasma current are observed using segmented Rogowski coils. Biased electrodes in the plasma are used to control rotation of external kinks and drive currents in the SOL. An extensive array of SOL current monitors and edge drive electrodes will be installed for pioneering studies of helical edge current control. Supported by U.S. DOE Grant DE-FG02-86ER53222.

  12. Current and Future Research in Active Control of Lightweight, Flexible Structures Using the X-56 Aircraft

    NASA Technical Reports Server (NTRS)

    Ryan, John J.; Bosworth, John T.; Burken, John J.; Suh, Peter M.

    2014-01-01

    The X-56 Multi-Utility Technology Testbed aircraft system is a versatile experimental research flight platform. The system was primarily designed to investigate active control of lightweight flexible structures, but is reconfigurable and capable of hosting a wide breadth of research. Current research includes flight experimentation of a Lockheed Martin designed active control flutter suppression system. Future research plans continue experimentation with alternative control systems, explore the use of novel sensor systems, and experiments with the use of novel control effectors. This paper describes the aircraft system, current research efforts designed around the system, and future planned research efforts that will be hosted on the aircraft system.

  13. Current Research Activities in Drive System Technology in Support of the NASA Rotorcraft Program

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Zakrajsek, James J.

    2006-01-01

    Drive system technology is a key area for improving rotorcraft performance, noise/vibration reduction, and reducing operational and manufacturing costs. An overview of current research areas that support the NASA Rotorcraft Program will be provided. Work in drive system technology is mainly focused within three research areas: advanced components, thermal behavior/emergency lubrication system operation, and diagnostics/prognostics (also known as Health and Usage Monitoring Systems (HUMS)). Current research activities in each of these activities will be presented. Also, an overview of the conceptual drive system requirements and possible arrangements for the Heavy Lift Rotorcraft program will be reviewed.

  14. Ionic current correlations underlie the global tuning of large numbers of neuronal activity attributes.

    PubMed

    Zhao, Shunbing; Golowasch, Jorge

    2012-09-26

    Ionic conductances in identified neurons are highly variable. This poses the crucial question of how such neurons can produce stable activity. Coexpression of ionic currents has been observed in an increasing number of neurons in different systems, suggesting that the coregulation of ionic channel expression, by thus linking their variability, may enable neurons to maintain relatively constant neuronal activity as suggested by a number of recent theoretical studies. We examine this hypothesis experimentally using the voltage- and dynamic-clamp techniques to first measure and then modify the ionic conductance levels of three currents in identified neurons of the crab pyloric network. We quantify activity by measuring 10 different attributes (oscillation period, spiking frequency, etc.), and find linear, positive and negative relationships between conductance pairs and triplets that can enable pyloric neurons to maintain activity attributes invariant. Consistent with experimental observations, some of the features most tightly regulated appear to be phase relationships of bursting activity. We conclude that covariation (and probably a tightly controlled coregulation) of ionic conductances can help neurons maintain certain attributes of neuronal activity invariant while at the same time allowing conductances to change over wide ranges in response to internal or environmental inputs and perturbations. Our results also show that neurons can tune neuronal activity globally via coordinate expression of ion currents.

  15. Comparison of elastolytic activity in lung lavage from current, ex- and non-smokers.

    PubMed

    Smith, S F; Guz, A; Burton, G H; Cooke, N T; Tetley, T D

    1988-01-01

    Cigarette smokers have an increased risk of developing a wide variety of lung diseases compared to non-smokers, and there have been many studies of the possible biochemical changes underlying this increased susceptibility. However, although epidemiological and physiological studies have shown that in the ex-smoker, the risk of smoking-related lung diseases falls between that of current and non-smokers, the biochemical and cellular mechanisms responsible for this intermediate status have not been investigated. In the present study, therefore, the extracellular elastolytic activities in lung lavage fluid from current, ex- and non-smokers have been compared. Elastolytic enzyme activity was investigated, since it is significantly elevated in lung lavage from smokers, and because it has been implicated in the development of pulmonary emphysema. In the subjects studied, extracellular elastolytic activities in lung lavage from ex-smokers were intermediate between those from current and non-smokers. There was no correlation between the time of abstinence from smoking, or the number of pack-years smoked and the extracellular elastolytic activities in ex-smokers' lung lavage. Elastolytic activity may remain elevated in ex-smokers' lungs for a number of reasons, including the persistence of particulate matter which may activate phagocytic cells on the lung surface. The possible significance of the raised elastolytic activity remains to be fully determined.

  16. Calcium-activated chloride currents in olfactory sensory neurons from mice lacking bestrophin-2.

    PubMed

    Pifferi, Simone; Dibattista, Michele; Sagheddu, Claudia; Boccaccio, Anna; Al Qteishat, Ahmed; Ghirardi, Filippo; Tirindelli, Roberto; Menini, Anna

    2009-09-01

    Olfactory sensory neurons use a chloride-based signal amplification mechanism to detect odorants. The binding of odorants to receptors in the cilia of olfactory sensory neurons activates a transduction cascade that involves the opening of cyclic nucleotide-gated channels and the entry of Ca(2+) into the cilia. Ca(2+) activates a Cl(-) current that produces an efflux of Cl(-) ions and amplifies the depolarization. The molecular identity of Ca(2+)-activated Cl(-) channels is still elusive, although some bestrophins have been shown to function as Ca(2+)-activated Cl(-) channels when expressed in heterologous systems. In the olfactory epithelium, bestrophin-2 (Best2) has been indicated as a candidate for being a molecular component of the olfactory Ca(2+)-activated Cl(-) channel. In this study, we have analysed mice lacking Best2. We compared the electrophysiological responses of the olfactory epithelium to odorant stimulation, as well as the properties of Ca(2+)-activated Cl(-) currents in wild-type (WT) and knockout (KO) mice for Best2. Our results confirm that Best2 is expressed in the cilia of olfactory sensory neurons, while odorant responses and Ca(2+)-activated Cl(-) currents were not significantly different between WT and KO mice. Thus, Best2 does not appear to be the main molecular component of the olfactory channel. Further studies are required to determine the function of Best2 in the cilia of olfactory sensory neurons.

  17. Calcium-activated chloride currents in olfactory sensory neurons from mice lacking bestrophin-2

    PubMed Central

    Pifferi, Simone; Dibattista, Michele; Sagheddu, Claudia; Boccaccio, Anna; Al Qteishat, Ahmed; Ghirardi, Filippo; Tirindelli, Roberto; Menini, Anna

    2009-01-01

    Olfactory sensory neurons use a chloride-based signal amplification mechanism to detect odorants. The binding of odorants to receptors in the cilia of olfactory sensory neurons activates a transduction cascade that involves the opening of cyclic nucleotide-gated channels and the entry of Ca2+ into the cilia. Ca2+ activates a Cl− current that produces an efflux of Cl− ions and amplifies the depolarization. The molecular identity of Ca2+-activated Cl− channels is still elusive, although some bestrophins have been shown to function as Ca2+-activated Cl− channels when expressed in heterologous systems. In the olfactory epithelium, bestrophin-2 (Best2) has been indicated as a candidate for being a molecular component of the olfactory Ca2+-activated Cl− channel. In this study, we have analysed mice lacking Best2. We compared the electrophysiological responses of the olfactory epithelium to odorant stimulation, as well as the properties of Ca2+-activated Cl− currents in wild-type (WT) and knockout (KO) mice for Best2. Our results confirm that Best2 is expressed in the cilia of olfactory sensory neurons, while odorant responses and Ca2+-activated Cl− currents were not significantly different between WT and KO mice. Thus, Best2 does not appear to be the main molecular component of the olfactory channel. Further studies are required to determine the function of Best2 in the cilia of olfactory sensory neurons. PMID:19622610

  18. Multi-object active shape model construction for abdomen segmentation: preliminary results.

    PubMed

    Gollmer, Sebastian T; Simon, Martin; Bischof, Arpad; Barkhausen, Jorg; Buzug, Thorsten M

    2012-01-01

    The automatic segmentation of abdominal organs is a pre-requisite for many medical applications. Successful methods typically rely on prior knowledge about the to be segmented anatomy as it is for instance provided by means of active shape models (ASMs). Contrary to most previous ASM based methods, this work does not focus on individual organs. Instead, a more holistic approach that aims at exploiting inter-organ relationships to eventually segment a complex of organs is proposed. Accordingly, a flexible framework for automatic construction of multi-object ASMs is introduced, employed for coupled shape modeling, and used for co-segmentation of liver and spleen based on a new coupled shape/separate pose approach. Our first results indicate feasible segmentation accuracies, whereas pose decoupling leads to substantially better segmentation results and performs in average also slightly better than the standard single-object ASM approach.

  19. Soil Moisture Active Passive (SMAP) Calibration and validation plan and current activities

    USDA-ARS?s Scientific Manuscript database

    The primary objective of the SMAP calibration and validation (Cal/Val) program is demonstrating that the science requirements (product accuracy and bias) have been met over the mission life. This begins during pre-launch with activities that contribute to high quality products and establishing post-...

  20. Estrone 3-sulfate mimics, inhibitors of estrone sulfatase activity: homology model construction and docking studies.

    PubMed

    Howarth, Nicola M; Purohit, Atul; Robinson, James J; Vicker, Nigel; Reed, Michael J; Potter, Barry V L

    2002-12-17

    Steroid sulfatase (STS) is a new target for the endocrine therapy of breast cancer. To ascertain some of the requirements for inhibition of estrone sulfatase activity, a number of novel analogues of estrone 3-O-sulfate possessing sulfate surrogates were synthesized and evaluated as inhibitors of estrone sulfatase (STS) in comparison to a lead inhibitor, estrone-3-O-methylthiophosphonate (E1-3-MTP). Using a selective enzyme digestion, one of the diastereoisomers of this compound, (R(p))-E1-3-MTP, could be prepared and evaluated. From structure-activity studies, we show that chirality at the phosphorus atom, hydrophobicity, basicity, size, and charge all influence the ability of a compound to inhibit estrone sulfatase activity. Of these, hydrophobicity seems to be the most important since simple, active nonsteroidal inhibitors, based on 5,6,7,8-tetrahydronaphth-2-ol (THN), can be prepared, provided that they are lipophilic enough to partition into a nonpolar environment. Also, a negatively charged group is favorable for optimal binding, although it appears that the presence of a potentially cleavable group can compensate for lack of charge in certain cases. A homology model of STS has been constructed from the STS sequence, and molecular docking studies of inhibitors have been performed to broaden the understanding of enzyme/inhibitor interactions. This model clearly shows the positions of the key amino acid residues His136, His290, Lys134, and Lys368 in the putative catalytic region of the formylglycine at position 75, with residues Asp35, Asp36, Asp342, and Gln343 as ligands in the coordination sphere of the magnesium ion. Docking studies using the substrate and estrone-3-sulfate mimics that are active inhibitors indicate they are positioned in the area of proposed catalysis, confirming the predictive power of the model.

  1. Acidosis inhibits spontaneous activity and membrane currents in myocytes isolated from the rabbit atrioventricular node.

    PubMed

    Cheng, Hongwei; Smith, Godfrey L; Orchard, Clive H; Hancox, Jules C

    2009-01-01

    Recent evidence from intact hearts suggests that the function of cardiac nodal tissue may be particularly susceptible to acidosis. Little is currently known, however, about the effects of acidosis on the cellular electrophysiology of the atrioventricular node (AVN). This study was conducted, therefore, to determine the effect of acidosis on the spontaneous activity and membrane currents of myocytes isolated from the rabbit AVN, recorded at 35-37 degrees C using whole-cell patch-clamp. Reduction of extracellular pH (pH(e); from 7.4 to 6.8 or 6.3) produced pH-dependent slowing of spontaneous action potential rate and upstroke velocity, and reductions in maximum diastolic potential and action potential amplitude. Ionic current recordings under voltage-clamp indicated that acidosis (pH(e) 6.3) decreased L-type Ca current (I(Ca,L)), without significant changes in voltage-dependent activation or inactivation. Acidosis reduced the E-4031-sensitive, rapid delayed rectifier current (I(Kr)) tail amplitude at -40 mV following command pulses to between -30 and +50 mV, and accelerated tail-current deactivation. In contrast, the time-dependent hyperpolarisation-activated current, I(f), was unaffected by acidosis. Background current insensitive to E-4031 and nifedipine was reduced by acidosis. Measurement of intracellular pH (pH(i)) from undialysed cells using BCECF showed a reduction in mean pH(i) from 7.24 to 6.45 (n=17) when pH(e) was lowered from 7.4 to 6.3. We conclude that I(f) is unlikely to be involved in the response of the AVN to acidosis, whilst inhibition of I(Ca,L) and I(Kr) by acidosis are likely to play a significant role in effects on AVN cellular electrophysiology.

  2. Epac activator critically regulates action potential duration by decreasing potassium current in rat adult ventricle.

    PubMed

    Brette, Fabien; Blandin, Erick; Simard, Christophe; Guinamard, Romain; Sallé, Laurent

    2013-04-01

    Sympathetic stimulation is an important modulator of cardiac function via the classic cAMP-dependent signaling pathway, PKA. Recently, this paradigm has been challenged by the discovery of a family of guanine nucleotide exchange proteins directly activated by cAMP (Epac), acting in parallel to the classic signaling pathway. In cardiac myocytes, Epac activation is known to modulate Ca(2+) cycling yet their actions on cardiac ionic currents remain poorly characterized. This study attempts to address this paucity of information using the patch clamp technique to record action potential (AP) and ionic currents on rat ventricular myocytes. Epac was selectively activated by 8-CPT-AM (acetoxymethyl ester form of 8-CPT). AP amplitude, maximum depolarization rate and resting membrane amplitude were unaltered by 8-CPT-AM, strongly suggesting that Na(+) current and inward rectifier K(+) current are not regulated by Epac. In contrast, AP duration was significantly increased by 8-CPT-AM (prolongation of duration at 50% and 90% of repolarization by 41±10% and 43±8% respectively, n=11). L-type Ca(2+) current density was unaltered by 8-CPT-AM (n=16) so this cannot explain the action potential lengthening. However, the steady state component of K(+) current was significantly inhibited by 8-CPT-AM (-38±6%, n=15), while the transient outward K(+) current was unaffected by 8-CPT-AM. These effects were PKA-independent since they were observed in the presence of PKA inhibitor KT5720. Isoprenaline (100nM) induced a significant prolongation of AP duration, even in the presence of KT5720. This study provides the first evidence that the cAMP-binding protein Epac critically modulates cardiac AP duration by decreasing steady state K(+) current. These observations may be relevant to diseases in which Epac is upregulated, like cardiac hypertrophy.

  3. Adenosine-activated potassium current in smooth muscle cells isolated from the pig coronary artery.

    PubMed Central

    Dart, C; Standen, N B

    1993-01-01

    1. The perforated patch technique with nystatin or amphotericin was used to record whole cell currents activated by adenosine in smooth muscle cells isolated enzymatically from pig coronary arteries. 2. Adenosine (5-40 microM) activated an outward current at a holding potential of 0 mV in 5 mM [K+]o and an inward current at -60 mV in 143 mM [K+]o. The dependence of the reversal potential for the adenosine-activated current on [K+]o suggests that it flows through K+ channels, while its current-voltage relation is consistent with the channels showing little voltage dependence. 3. The adenosine-activated current was inhibited by the sulphonylurea glibenclamide (5 microM) and by phencyclidine (5 microM). It was unaffected by charybdotoxin (50 nM) or apamin (100 nM), blockers of large and small conductance Ca(2+)-activated K+ channels respectively. 4. At -60 mV in 143 mM K+ solution, openings of single channels passing a current of just over -2 pA could sometimes be detected in the absence of adenosine. Openings became more frequent after the application of adenosine, with several levels then being detected. Openings of channels with a larger conductance were sometimes also seen in the presence of adenosine. Fluctuation analysis gave somewhat lower estimates of unitary current than did direct measurements. 5. The effect of adenosine could be mimicked by the A1 receptor agonist CCPA (2-chloro-N6-cyclopentyladenosine), while the A2 agonist CGS 21680 (2-p-(2-carboxethyl)phenethylamino-5'-N-ethylcarboxamido adenosine hydrochloride) was without effect. The response to adenosine was inhibited by the A1 antagonist DPCPX (8-cyclopentyl-1,3-dipropylxanthine), but was unaffected by the A2 antagonist CGS 15943A (5-amino-9-chloro-2-(2-furanyl)-1,2,4- triazolo[1,5-C]quinazoline monomethanesulphonate). 6. Our results suggest that adenosine acts at an A1 receptor to activate K+ channels. We consider it most likely that these are ATP-dependent K+ channels. We discuss the mechanism by

  4. Induction of self awareness in dreams through frontal low current stimulation of gamma activity.

    PubMed

    Voss, Ursula; Holzmann, Romain; Hobson, Allan; Paulus, Walter; Koppehele-Gossel, Judith; Klimke, Ansgar; Nitsche, Michael A

    2014-06-01

    Recent findings link fronto-temporal gamma electroencephalographic (EEG) activity to conscious awareness in dreams, but a causal relationship has not yet been established. We found that current stimulation in the lower gamma band during REM sleep influences ongoing brain activity and induces self-reflective awareness in dreams. Other stimulation frequencies were not effective, suggesting that higher order consciousness is indeed related to synchronous oscillations around 25 and 40 Hz.

  5. Current and future activities in the area of optical space communications in Japan

    NASA Astrophysics Data System (ADS)

    Fujise, Masayuki; Araki, Ken'ichi; Arikawa, Hiroshi; Furuhama, Yoji

    1991-05-01

    An account is given of current and prospective activities in Japan in the field of optical space communications (OSC) and its associated optical technologies. These activities are conducted by NASDA, the Advanced Telecommunications Research Institute, and the Ministry of Posts and Telecommunications. Attention is given to such initiatives as high-precision tracking, bidirectional OSC, laser beam propagation, optical ground stations, and a free-space simulator for laser transmission.

  6. Feedback from physical activity monitors is not compatible with current recommendations: A recalibration study.

    PubMed

    Thompson, Dylan; Batterham, Alan M; Peacock, Oliver J; Western, Max J; Booso, Rahuman

    2016-10-01

    Wearable devices to self-monitor physical activity have become popular with individuals and healthcare practitioners as a route to the prevention of chronic disease. It is not currently possible to reconcile feedback from these devices with activity recommendations because the guidelines refer to the amount of activity required on top of normal lifestyle activities (e.g., 150 minutes of moderate-to-vigorous intensity activity per week over-and-above normal moderate-to-vigorous lifestyle activities). The aim of this study was to recalibrate the feedback from self-monitoring. We pooled data from four studies conducted between 2006 and 2014 in patients and volunteers from the community that included both sophisticated measures of physical activity and 10-year risk for cardiovascular disease and type 2 diabetes (n=305). We determined the amount of moderate-to-vigorous intensity activity that corresponded to FAO/WHO/UNU guidance for a required PAL of 1.75 (Total Energy Expenditure/Basal Metabolic Rate). Our results show that, at the UK median PAL, total moderate-to-vigorous intensity physical activity will be around 735 minutes per week (~11% of waking time). We estimate that a 4% increase in moderate-to-vigorous intensity activity will achieve standardised guidance from FAO/WHO/UNU and will require ~1000 minutes of moderate-to-vigorous intensity activity per week. This study demonstrates that feedback from sophisticated wearable devices is incompatible with current physical activity recommendations. Without adjustment, people will erroneously form the view that they are exceeding recommendations by several fold. A more appropriate target from self-monitoring that accounts for normal moderate-to-vigorous lifestyle activities is ~1000 minutes per week, which represents ~15% of waking time. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Anemonia sulcata toxins modify activation and inactivation of Na+ currents in a crayfish neurone.

    PubMed

    Hartung, K; Rathmayer, W

    1985-05-01

    The effects of three toxins (ATX I, II, III) isolated from the sea anemone Anemonia sulcata were studied in the soma membrane of a crustacean neurone under voltage-clamp conditions. All three toxins affected the action potentials and the Na+ currents in a similar manner. The lowest concentrations tested (10 nM, 20 nM and 50 nM for ATX I, II and III, respectively) had pronounced selective effects on the Na+ current. No effect on K+ or Ca2+ currents was observed with concentrations up to 5 microM. In the presence of ATX the Na+ inactivation was incomplete even with pulses of 700 ms length or strong depolarizing prepulses. Besides the effects on the inactivation process ATX affected also the activation of the Na+ current. In cells treated with ATX the negative resistance branch of the peak Na+ current voltage relation was shifted by -5 mV to -20 mV. The time to peak was increased for small depolarizations (up to -30 mV) and the rate of rise (delta I/delta t) was enlarged by ATX. A slow activating current component was also observed after depolarizing prepulses or if the Na+ current was outward. The decay of the Na+ tail currents was considerably prolonged after the application of ATX if the membrane was repolarized to potentials more positive than about -60 mV. Repetitive stimulation led to a shortening of the action potential in ATX II treated neurones. A simultaneous and parallel decrement of the peak and plateau current was observed with depolarizing voltage steps.

  8. Direct Anandamide Activation of TRPV1 Produces Divergent Calcium and Current Responses.

    PubMed

    Fenwick, Axel J; Fowler, Daniel K; Wu, Shaw-Wen; Shaffer, Forrest J; Lindberg, Jonathan E M; Kinch, Dallas C; Peters, James H

    2017-01-01

    In the brainstem nucleus of the solitary tract (NTS), primary vagal afferent neurons express the transient receptor potential vanilloid subfamily member 1 (TRPV1) at their central terminals where it contributes to quantal forms of glutamate release. The endogenous membrane lipid anandamide (AEA) is a putative TRPV1 agonist in the brain, yet the extent to which AEA activation of TRPV1 has a neurophysiological consequence is not well established. We investigated the ability of AEA to activate TRPV1 in vagal afferent neurons in comparison to capsaicin (CAP). Using ratiometric calcium imaging and whole-cell patch clamp recordings we confirmed that AEA excitatory activity requires TRPV1, binds competitively at the CAP binding site, and has low relative affinity. While AEA-induced increases in peak cytosolic calcium were similar to CAP, AEA-induced membrane currents were significantly smaller. Removal of bath calcium increased the AEA current with no change in peak CAP currents revealing a calcium sensitive difference in specific ligand activation of TRPV1. Both CAP- and AEA-activated TRPV1 currents maintained identical reversal potentials, arguing against a major difference in ion selectivity to resolve the AEA differences in signaling. In contrast with CAP, AEA did not alter spontaneous glutamate release at NTS synapses. We conclude: (1) AEA activation of TRPV1 is markedly different from CAP and produces different magnitudes of calcium influx from whole-cell current; and (2) exogenous AEA does not alter spontaneous glutamate release onto NTS neurons. As such, AEA may convey modulatory changes to calcium-dependent processes, but does not directly facilitate glutamate release.

  9. Temperature dependence of rapidly adapting mechanically activated currents in rat dorsal root ganglion neurons.

    PubMed

    Jia, Zhanfeng; Ling, Jennifer; Gu, Jianguo G

    2012-08-01

    Rapidly adapting mechanically activated channels (RA) are expressed on somatosensory neurons and thought to play a role in mechanical transduction. Because mechanical sensations can be significantly affected by temperatures, we examined thermal sensitivity of RA currents in cultured dorsal root ganglion (DRG) neurons to see if RA channel activity is highly temperature-dependent. RA currents were evoked from DRG neurons by membrane displacements and recorded by the whole-cell patch-clamp recording technique. We found that RA currents were significantly enhanced by warming temperatures from 22 to 32 °C and reduced by cooling temperatures from 24 to 14 °C. RA channel activation exhibited steep temperature-dependence with a large temperature coefficient (Q10>5) and a high activation energy (Ea>30 kcal/mol). We further showed that RA channel activation by mechanical stimulation led to membrane depolarization, which could result in action potential firing at 22 °C or 32 °C but not at 14 °C. Taken together, our results provide the measurements of thermal dynamics and activation energy of RA channels, and suggest that a high energy barrier is present for RA channels to open. These findings are in agreement with temperature sensitivity of mechanical sensations in mammals.

  10. Antibacterial efficacy and cytotoxicity of low intensity direct current activated silver-titanium implant system prototype.

    PubMed

    Tan, Zhuo; Havell, Edward A; Orndorff, Paul E; Shirwaiker, Rohan A

    2017-02-01

    Silver-based devices activated by electric current are of interest in biomedicine because of their broad-spectrum antimicrobial activity. This study investigates the in vitro antibacterial efficacy and cytotoxicity of a low intensity direct current (LIDC)-activated silver-titanium implant system prototype designed for localized generation and delivery of silver ions at the implantation site. First, the antibacterial efficacy of the system was assessed against methicillin-resistant Staphylococcus aureus (MRSA) over 48 h at current levels of 3 and 6 µA in Mueller-Hinton broth. The cytotoxicity of the system was then evaluated over 48 h in two phases using an in vitro model with in which the activated electrodes were suspended in growth medium in a cell-seeded tissue culture plate. In phase-1, the system was tested on human osteosarcoma (MG-63) cell line and compared to titanium controls. In phase-2, the cytotoxicity characteristics were validated with normal human diploid osteoblast cells. The LIDC-activated system demonstrated high antimicrobial efficacy against MRSA, but was also toxic to human cells immediately surrounding the electrodes. The statistical analysis showed that the cytotoxicity was a result of the presence of silver, and the electric activation did not make it worse.

  11. VIP in construction: systematic development and evaluation of a multifaceted health programme aiming to improve physical activity levels and dietary patterns among construction workers

    PubMed Central

    2012-01-01

    Background The prevalence of both overweight and musculoskeletal disorders (MSD) in the construction industry is high. Many interventions in the occupational setting aim at the prevention and reduction of these health problems, but it is still unclear how these programmes should be designed. To determine the effectiveness of interventions on these health outcomes randomised controlled trials (RCTs) are needed. The aim of this study is to systematically develop a tailored intervention for prevention and reduction of overweight and MSD among construction workers and to describe the evaluation study regarding its (cost-)effectiveness. Methods/Design The Intervention Mapping (IM) protocol was applied to develop and implement a tailored programme aimed at the prevention and reduction of overweight and MSD. The (cost-) effectiveness of the intervention programme will be evaluated using an RCT. Furthermore, a process evaluation will be conducted. The research population will consist of blue collar workers of a large construction company in the Netherlands. Intervention The intervention programme will be aimed at improving (vigorous) physical activity levels and healthy dietary behaviour and will consist of tailored information, face-to-face and telephone counselling, training instruction (a fitness "card" to be used for exercises), and materials designed for the intervention (overview of the company health promoting facilities, waist circumference measuring tape, pedometer, BMI card, calorie guide, recipes, and knowledge test). Main study parameters/endpoints The intervention effect on body weight and waist circumference (primary outcome measures), as well as on lifestyle behaviour, MSD, fitness, CVD risk indicators, and work-related outcomes (i.e. productivity, sick leave) (secondary outcome measures) will be assessed. Discussion The development of the VIP in construction intervention led to a health programme tailored to the needs of construction workers. This programme

  12. VIP in construction: systematic development and evaluation of a multifaceted health programme aiming to improve physical activity levels and dietary patterns among construction workers.

    PubMed

    Viester, Laura; Verhagen, Evert A L M; Proper, Karin I; van Dongen, Johanna M; Bongers, Paulien M; van der Beek, Allard J

    2012-01-30

    The prevalence of both overweight and musculoskeletal disorders (MSD) in the construction industry is high. Many interventions in the occupational setting aim at the prevention and reduction of these health problems, but it is still unclear how these programmes should be designed. To determine the effectiveness of interventions on these health outcomes randomised controlled trials (RCTs) are needed. The aim of this study is to systematically develop a tailored intervention for prevention and reduction of overweight and MSD among construction workers and to describe the evaluation study regarding its (cost-)effectiveness. The Intervention Mapping (IM) protocol was applied to develop and implement a tailored programme aimed at the prevention and reduction of overweight and MSD. The (cost-) effectiveness of the intervention programme will be evaluated using an RCT. Furthermore, a process evaluation will be conducted. The research population will consist of blue collar workers of a large construction company in the Netherlands. The intervention programme will be aimed at improving (vigorous) physical activity levels and healthy dietary behaviour and will consist of tailored information, face-to-face and telephone counselling, training instruction (a fitness "card" to be used for exercises), and materials designed for the intervention (overview of the company health promoting facilities, waist circumference measuring tape, pedometer, BMI card, calorie guide, recipes, and knowledge test). MAIN STUDY PARAMETERS/ENDPOINTS: The intervention effect on body weight and waist circumference (primary outcome measures), as well as on lifestyle behaviour, MSD, fitness, CVD risk indicators, and work-related outcomes (i.e. productivity, sick leave) (secondary outcome measures) will be assessed. The development of the VIP in construction intervention led to a health programme tailored to the needs of construction workers. This programme, if proven effective, can be directly

  13. Metabolic inhibition enhances Ca(2+)-activated K+ current in smooth muscle cells of rabbit portal vein.

    PubMed

    Miller, A L; Morales, E; Leblanc, N R; Cole, W C

    1993-12-01

    The effect of metabolic inhibition on macroscopic and single-channel K+ currents in isolated rabbit portal vein myocytes was investigated by patch-clamp technique. Depression of adenosine triphosphate synthesis was produced by 2-deoxy-D-glucose (10 mM) and either cyanide (2 mM) or dinitrophenol (50 microM). Outward quasi-steady-state current evoked by a ramp protocol and outward time-dependent current during step depolarizations were increased during metabolic inhibition. The reversal potential for quasi-steady-state current shifted negatively toward equilibrium potential of K+ during treatment consistent with a role for K+ conductance and hyperpolarization of membrane potential. The macroscopic K+ current affected was 1) voltage dependent, 2) inhibited by intracellular Ca2+ chelation and low tetraethylammonium ion (1 mM) but unaffected by 4-aminopyridine (2 mM), and 3) associated with a rise in intracellular Ca2+ assessed by indo 1. Metabolic inhibition caused an increase in voltage-dependent large-conductance K+ channel (120-130 pS) activity in cell-attached patches of myocytes bathed in physiological solution (140 mM K+ in pipette). The channels were blocked in a flickery fashion by tetraethylammonium ion (0.5 mM) and inhibited with charybdotoxin (100 nM). We conclude that metabolic inhibition increases the activity of large-conductance Ca(2+)-activated K+ channels in vascular smooth muscle.

  14. Osteoclast spreading kinetics are correlated with an oscillatory activation of a calcium-dependent potassium current.

    PubMed

    Espinosa, Leon; Paret, Laurent; Ojeda, Carlos; Tourneur, Yves; Delmas, Pierre D; Chenu, Chantal

    2002-10-01

    Cell movement and spreading involve calcium-dependent processes and ionic channel activation. During bone resorption, osteoclasts alternate between spread, motile and resorptive phases. We investigated whether the electrical membrane properties of osteoclasts were linked to their membrane morphological changes. Rabbit osteoclasts were recorded by time-lapse videomicroscopy performed simultaneously with patch-clamp whole cell and single channel recordings. Original image analysis methods were developed and used to demonstrate for the first time an oscillatory activation of a spontaneous membrane current in osteoclasts, which is directly correlated to the membrane movement rate. This current was identified as a calcium-dependent potassium current (IK(Ca)) that is sensitive to both charybdotoxin and apamin and was generated by a channel with unitary conductance of approximately 25+/-2 pS. Blockade of this current also decreased osteoclast spreading and inhibited bone resorption in vitro, demonstrating a physiological role for this current in osteoclast activity. These results establish for the first time a temporal correlation between lamellipodia formation kinetics and spontaneous peaks of IK(Ca), which are both involved in the control of osteoclast spreading and bone resorption.

  15. The morphology of flare phenomena, magnetic fields, and electric currents in active regions. III - NOAA active region 6233 (1990 August)

    NASA Technical Reports Server (NTRS)

    De La Beaujardiere, J.-F.; Canfield, Richard C.; Leka, K. D.

    1993-01-01

    We investigate the spatial relationship between vertical electric currents and flare phenomena in NOAA Active Region 6233, which was observed 1990, August 28-31 at Mees Solar Observatory. The two flares studied are the 1N/M1.8 flare on August 28, 22:30 UT and the 1N/M1.6 flare on August 29, 20:35 UT. Using Stokes polarimetry we make magnetograms of the region and compute the vertical current density. Using H-alpha imaging spectroscopy we identify sites of intense nonthermal electron precipitation or of high coronal pressure. The precipitation in these flares is barely strong enough to be detectable. We find that both precipitation and high pressure tend to occur near vertical currents, but that neither phenomenon is cospatial with current maxima. In contrast with the conclusion of other authors, we argue that these observations do not support a current-interruption model for flares, unless the relevant currents are primarily horizontal. The magnetic morphology and temporal evolution of these flares suggest that an erupting filament model may be relevant, but this model does not explicitly predict the relationship between precipitation, high pressure, and vertical currents.

  16. Cesium blockade of delayed outward currents and electrically induced pacemaker activity in mammalian ventricular myocardium

    PubMed Central

    1981-01-01

    The effects of Cs+, 5-25 mM, were studied in cat and guinea pig papillary muscles using voltage clamp and current clamp techniques. In solutions containing normal K+, the major effects of Cs+ were depolarization of the resting potential and reduction of the delayed outward current (ixl) between -80 and -20 mV. Both inward and outward portions of the isochronal current voltage relation (l-s clamps) were reduced by extracellular Cs+. This resulted in a substantial reduction of inward rectification and, by subtraction from the normal I-V relationship, the definition of a Cs+-sensitive component of current. Under current clamp conditions, 5-10 mM Cs+ produced a dose-dependent slowing of repetitive firing induced by depolarization. At higher concentrations (25 mM) the resting potential was depolarized and repetitive activity could not be induced by further depolarization. However, release of hyperpolarizing pulses was followed by prolonged bursts of repetitive action potentials, suggesting partial reversal of blockade or participation of another pacemaker process. The experimental results and a numerical simulation show that under readily attainable conditions, reduction in an outward pacemaker current may slow pacemaker activity. PMID:6262430

  17. Cesium blockade of delayed outward currents and electrically induced pacemaker activity in mammalian ventricular myocardium.

    PubMed

    Meier, C F; Katzung, B G

    1981-05-01

    The effects of Cs+, 5-25 mM, were studied in cat and guinea pig papillary muscles using voltage clamp and current clamp techniques. In solutions containing normal K+, the major effects of Cs+ were depolarization of the resting potential and reduction of the delayed outward current (ixl) between -80 and -20 mV. Both inward and outward portions of the isochronal current voltage relation (l-s clamps) were reduced by extracellular Cs+. This resulted in a substantial reduction of inward rectification and, by subtraction from the normal I-V relationship, the definition of a Cs+-sensitive component of current. Under current clamp conditions, 5-10 mM Cs+ produced a dose-dependent slowing of repetitive firing induced by depolarization. At higher concentrations (25 mM) the resting potential was depolarized and repetitive activity could not be induced by further depolarization. However, release of hyperpolarizing pulses was followed by prolonged bursts of repetitive action potentials, suggesting partial reversal of blockade or participation of another pacemaker process. The experimental results and a numerical simulation show that under readily attainable conditions, reduction in an outward pacemaker current may slow pacemaker activity.

  18. A statistical study of current-sheet formation above solar active regions based on selforganized criticality

    NASA Astrophysics Data System (ADS)

    Dimitropoulou, M.; Isliker, H.; Vlahos, L.; Georgoulis, M.; Anastasiadis, A.; Toutountzi, A.

    2013-09-01

    We treat flaring solar active regions as physical systems having reached the self-organized critical state. Their evolving magnetic configurations in the low corona may satisfy an instability criterion, related to the excession of a specific threshold in the curl of the magnetic field. This imposed instability criterion implies an almost zero resistivity everywhere in the solar corona, except in regions where magnetic-field discontinuities and. hence, local currents, reach the critical value. In these areas, current-driven instabilities enhance the resistivity by many orders of magnitude forming structures which efficiently accelerate charged particles. Simulating the formation of such structures (thought of as current sheets) via a refined SOC cellular-automaton model provides interesting information regarding their statistical properties. It is shown that the current density in such unstable regions follows power-law scaling. Furthermore, the size distribution of the produced current sheets is best fitted by power laws, whereas their formation probability is investigated against the photospheric magnetic configuration (e.g. Polarity Inversion Lines, Plage). The average fractal dimension of the produced current sheets is deduced depending on the selected critical threshold. The above-mentioned statistical description of intermittent electric field structures can be used by collisional relativistic test particle simulations, aiming to interpret particle acceleration in flaring active regions and in strongly turbulent media in astrophysical plasmas. The above work is supported by the Hellenic National Space Weather Research Network (HNSWRN) via the THALIS Programme.

  19. NSAIDs modulate GABA-activated currents via Ca2+-activated Cl− channels in rat dorsal root ganglion neurons

    PubMed Central

    ZHAO, LEI; LI, LI; MA, KE-TAO; WANG, YANG; LI, JING; SHI, WEN-YAN; ZHU, HE; ZHANG, ZHONG-SHUANG; SI, JUN-QIANG

    2016-01-01

    The ability of non-steroidal anti-inflammatory drugs (NSAIDs) to modulate γ-aminobutyrate (GABA)-activated currents via Ca2+-activated Cl− channels in rat dorsal root ganglion neurons (DRG), was examined in the present study. During the preparation of DRG neurons harvested from Sprague-Dawley rats, the whole-cell recording technique was used to record the effect of NSAIDs on GABA-activated inward currents, and the expression levels of the TMEM16A and TMEM16B subunits were revealed. In the event that DRG neurons were pre-incubated for 20 sec with niflumic acid (NFA) and 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) prior to the administration of GABA, the GABA-induced inward currents were diminished markedly in the majority of neurons examined (96.3%). The inward currents induced by 100 µmol/l GABA were attenuated by (0±0.09%; neurons = 4), (5.32±3.51%; neurons = 6), (21.3±4.00%; neurons = 5), (33.8±5.20%; neurons = 17), (52.2±5.10%; neurons = 4) and (61.1±4.12%; neurons = 12) by 0.1, 1, 3, 10, 30 and 100 µmol/l NFA, respectively. The inward currents induced by 100 µmol/l GABA were attenuated by (13.8±6%; neurons = 6), (23.2±14.7%; neurons = 6) and (29.7±9.1%; neurons = 9) by 3, 10 and 30 µmol/l NPPB, respectively. NFA and NPPB dose-dependently inhibited GABA-activated currents with half maximal inhibitory concentration (IC50) values of 6.7 and 11 µmol/l, respectively. The inhibitory effect of 100 µmol/l NFA on the GABA-evoked inward current were also strongly inhibited by nitrendipine (NTDP; an L-type calcium channel blocker), 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid tetrakis (a highly selective calcium chelating reagent), caffeine (a widely available Ca2+ consuming drug) and calcium-free extracellular fluid, in a concentration-dependent manner. Immunofluorescent staining indicated that TMEM16A and TMEM16B expression was widely distributed in DRG neurons. The results suggest that NSAIDs may be able to regulate Ca2

  20. 76 FR 39414 - Agency Information Collection Activities: Form I-694, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-06

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-694, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 694, Notice of Appeal of Decision Under Section 210 or 245A of...

  1. 76 FR 40385 - Agency Information Collection Activities: Form I-907, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-08

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-907, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day notice of information collection under review: form I- 907, request for premium processing service. The Department of...

  2. 75 FR 74071 - Agency Information Collection Activities: Form I-601, Revision of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-30

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-601, Revision of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection Under Review: Form I- 601, Application for Waiver of Grounds of Inadmissibility; OMB...

  3. 75 FR 37821 - Agency Information Collection Activities: Form I-751, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-30

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-751, Extension of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection Under Review: Form I- 751, Petition to Remove Conditions on Residence; OMB Control No...

  4. 76 FR 69275 - Agency Information Collection Activities: Form I-192, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-08

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-192, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 192, Application for Advance Permission to Enter as Nonimmigrant...

  5. 77 FR 33758 - Agency Information Collection Activities: Form I-829, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-07

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-829, Extension of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection Under Review: Form I- 829, Petition by Entrepreneur to Remove Conditions. The...

  6. 75 FR 11898 - Agency Information Collection Activities: Form I-612, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-12

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-612, Extension of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection Under Review: Form I- 612, Application for Waiver of the Foreign Residence Requirement...

  7. 76 FR 11808 - Agency Information Collection Activities: Form I-590, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-03

    ... abstract: Primary: Individuals or Households. Form I- 590 provides a uniform method for applicants to apply... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-590, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of...

  8. 75 FR 32799 - Agency Information Collection Activities: Form I-243, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-09

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-243, Extension of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection Under Review: Form I- 243, Application for Removal; OMB Control No. 1615-0019. The...

  9. 75 FR 76745 - Agency Information Collection Activities: Form I-601, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-09

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-601, Extension of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection Under Review: Form I- 601, Application for Waiver of Grounds of Inadmissibility; OMB...

  10. 76 FR 20362 - Agency Information Collection Activities: Form I-905, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-12

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-905, Extension of a Currently Approved Information Collection; Comment Request Action: 60-Day Notice of Information Collection Under Review: Form I- 905, Application for Authorization To Issue Certification for...

  11. 76 FR 71056 - Agency Information Collection Activities: Form I-566, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-16

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-566, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 566, Interagency Record of Request, A, G or NATO Dependent...

  12. 76 FR 11805 - Agency Information Collection Activities: Form I-134, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-03

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-134, Extension of a Currently Approved Information Collection; Comment Request. ACTION: 30-Day Notice of Information Collection Under Review: Form I- 134, Affidavit of Support; OMB Control No. 1615-0014. The...

  13. 76 FR 66946 - Agency Information Collection Activities: Form I-539, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-539, Extension of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection Under Review: Form I- 539, Application to Extend/Change Nonimmigrant Status. OMB...

  14. 75 FR 29779 - Agency Information Collection Activities: Form I-918, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-27

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-918, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 918, Petition for U Nonimmigrant Status; and Supplement A and B...

  15. 77 FR 33759 - Agency Information Collection Activities: Form I-601, Revision of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-07

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-601, Revision of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 601, Application for Waiver of Grounds of Inadmissibility. The...

  16. 75 FR 70016 - Agency Information Collection Activities: Form I-566, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-16

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-566, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 566, Interagency Record of Individual Requesting Change...

  17. 76 FR 43335 - Agency Information Collection Activities: Form I-765, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-20

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-765, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 756, Application for Employment Authorization; OMB Control No...

  18. 75 FR 41215 - Agency Information Collection Activities: Form I-821, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-15

    ... required to respond, as well as a brief abstract: Primary: Individuals or Households. Form I- 821 is... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-821, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of...

  19. 75 FR 74070 - Agency Information Collection Activities: Form I-829, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-30

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-829, Extension of a Currently Approved Information Collection; Comment Request ACTION: 60-Day notice of information collection under review: Form I- 829, Petition by Entrepreneur to Remove Conditions; OMB Control...

  20. 75 FR 29780 - Agency Information Collection Activities: Form I-612, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-27

    ... abstract: Primary: Individuals or Households. Form I- 612 is used by USCIS to determine eligibility for a... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-612, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of...

  1. 76 FR 20361 - Agency Information Collection Activities: Form I-694, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-12

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-694, Extension of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection Under Review: Form I- 694, Notice of Appeal of Decision Under Section 210 or 245A; OMB...

  2. 75 FR 12250 - Agency Information Collection Activities: Form I-191, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-15

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-191, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection under Review: Form I- 191, Application for Advance Permission to Return to...

  3. 75 FR 52541 - Agency Information Collection Activities: Form I-243, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-26

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-243, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 243, Application for Removal; OMB Control No. 1615-0019. The...

  4. 76 FR 69274 - Agency Information Collection Activities: Form I-817, Extension of a Currently Approved...

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    2011-11-08

    ... SECURITY Citizenship and Immigration Services Agency Information Collection Activities: Form I-817, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 817, Application for Family Unity Benefits; OMB Control No. 1615...

  5. 75 FR 41215 - Agency Information Collection Activities: Form I-687, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-15

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-687, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 687, Application for Status as Temporary Resident Under Section...

  6. 77 FR 9259 - Agency Information Collection Activities: Form I-361, Extension of a Currently Approved...

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    2012-02-16

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-361, Extension of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection Under Review: Form I- 361, Affidavit of Financial Support and Intent To Petition for...

  7. 77 FR 35419 - Agency Information Collection Activities: Form I-601, Revision of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-13

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-601, Revision of a Currently Approved Information Collection; Correction ACTION: 30-Day Notice of Information Collection Under Review: Form I- 601, Application for Waiver of Grounds of Inadmissibility; Correction. On...

  8. 76 FR 12364 - Agency Information Collection Activities: Form I-881, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-07

    ... or Households. Form I- 881 is used by a nonimmigrant to apply for suspension of deportation or... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-881, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of...

  9. 75 FR 52541 - Agency Information Collection Activities: Form I-865, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-26

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-865, Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 865, Sponsor's Notice of Change of Address; OMB Control No. 1615...

  10. 76 FR 16800 - Agency Information Collection Activities: Form I-601, Revision of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-25

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-601, Revision of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 601, Application for Waiver of Grounds of Inadmissibility; OMB...

  11. 77 FR 21104 - Agency Information Collection Activities: Form I-694, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-09

    ... a brief abstract: Primary: Individuals and households. USCIS uses the information provided on Form I... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-694, Extension of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of...

  12. 77 FR 15184 - Agency Information Collection Activities; Revision of a Currently-Approved Information Collection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-14

    ..., ``Designation of Agents, Motor Carriers, Brokers and Freight Forwarders (OMB Control Number 2126-0015),'' which... TRANSPORTATION Federal Motor Carrier Safety Administration Agency Information Collection Activities; Revision of a Currently-Approved Information Collection Request: Designation of Agents, Motor Carriers, Brokers...

  13. The Current Status of Classroom Inclusion Activities of Secondary Agriculture Teachers

    ERIC Educational Resources Information Center

    Hoerst, Caryn M.; Whittington, M. Susie

    2009-01-01

    The current status of classroom inclusion activities among agriculture teachers in comprehensive secondary agricultural education programs in Ohio is reported. The researchers describe secondary agriculture teachers' needs related to teaching learners with special needs in inclusion classes, given legislative mandates. Specifically, the…

  14. 77 FR 55862 - Agency Information Collection Activities; Revision of Currently Approved Collection; Comments...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... of Justice Programs Agency Information Collection Activities; Revision of Currently Approved Collection; Comments Requested: Office for Victims of Crime Training and Technical Assistance Center (OVC... Department of Justice, Office of Justice Programs, Office for Victims of Crime, will be submitting the...

  15. 76 FR 38207 - Agency Information Collection Activities: Extension of a Currently Approved Information Collection

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-29

    ... Management and Budget (OMB) to approve the information collection request (ICR) described below. As required... National Park Service Agency Information Collection Activities: Extension of a Currently Approved Information Collection AGENCY: National Park Service, Interior. ] ACTION: Notice of a revision of a...

  16. 77 FR 3278 - Agency Information Collection Activities: Form G-1145; Revision of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-23

    ... Information Collection Activities: Form G-1145; Revision of a Currently Approved Information Collection... Application/Petition Acceptance, Form G-1145. The Department of Homeland Security, U.S. Citizenship and... extension of the Form G-1145. Please do not submit requests for individual case status inquiries to this...

  17. 77 FR 32138 - Agency Information Collection Activities: Extension of a Currently Approved Collection; Comments...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-31

    ...: National Crime Victimization Survey (NCVS). (3) Agency form number, if any, and the applicable component of... of Justice Programs Agency Information Collection Activities: Extension of a Currently Approved Collection; Comments Requested National Crime Victimization Survey (NCVS) ACTION: 30-day notice of...

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    Federal Register 2010, 2011, 2012, 2013, 2014

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    ... Information Collection Activities; Extension of Currently Approved Collection; Comments Requested; Semi-Annual Progress Report for the Grants to Indian Tribal Governments Program ACTION: 30-Day Notice of Information...-Annual Progress Report for Grants to Indian Tribal Governments Program. ] (3) Agency form number, if...

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    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-05

    ... Federal Motor Carrier Safety Administration Agency Information Collection Activities; Extension of a Currently Approved Collection: Driver Qualification Files AGENCY: Federal Motor Carrier Safety...., Washington, DC between 9 a.m. and 5 p.m., e.t., Monday through Friday, except Federal holidays....

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    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ... SECURITY Citizenship and Immigration Services Agency Information Collection Activities: Form I-129F; Extension of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection Under Review: Form I- 129F, Petition for Alien Fiance(e). OMB Control No. 1615-0001...

  1. Video: Animals; Electric Current; Force; Science Activities. Learning in Science Project. Working Papers 51-54.

    ERIC Educational Resources Information Center

    Bell, Beverley; And Others

    Four papers to be used in conjunction with video-tapes developed by the Learning in Science Project are presented. Topic areas of the papers focus on: (1) animals; (2) electric current; (3) force; and (4) science activities. The first paper presents transcripts of class discussions focusing on the scientific meaning of the word animal. The second…

  2. 78 FR 63493 - Agency Information Collection Activities; Extension of a Currently Approved Collection: Semi...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-24

    .../Collection: Semi-annual Progress Report for the Technical Assistance Program. ] (3) Agency form number, if... Information Collection Activities; Extension of a Currently Approved Collection: Semi-Annual Progress Report for the Technical Assistance Program ACTION: 30-day notice. The Department of Justice, Office...

  3. 78 FR 16894 - Agency Information Collection Activities: Renewal of Currently Approved Collection; Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-19

    ... TRANSPARENCY BOARD Agency Information Collection Activities: Renewal of Currently Approved Collection; Comment.... SUMMARY: The Recovery Accountability and Transparency Board (Board) is giving public notice that it will... comments to Sharon Mar, Desk Officer for the Recovery Accountability and Transparency Board, Office of...

  4. 78 FR 4175 - Agency Information Collection Activities: Renewal of Currently Approved Collection; Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-18

    ... From the Federal Register Online via the Government Publishing Office RECOVERY ACCOUNTABILITY AND TRANSPARENCY BOARD Agency Information Collection Activities: Renewal of Currently Approved Collection; Comment Request Correction In notice document 2012-30952, appearing on page 76097, in the issue of Wednesday...

  5. Summary of Current and Future MSFC International Space Station Environmental Control and Life Support System Activities

    NASA Technical Reports Server (NTRS)

    Ray, Charles D.; Carrasquillo, Robyn L.; Minton-Summers, Silvia

    1997-01-01

    This paper provides a summary of current work accomplished under technical task agreement (TTA) by the Marshall Space Flight Center (MSFC) regarding the Environmental Control and Life Support System (ECLSS) as well as future planning activities in support of the International Space Station (ISS). Current activities include ECLSS computer model development, component design and development, subsystem integrated system testing, life testing, and government furnished equipment delivered to the ISS program. A long range plan for the MSFC ECLSS test facility is described whereby the current facility would be upgraded to support integrated station ECLSS operations. ECLSS technology development efforts proposed to be performed under the Advanced Engineering Technology Development (AETD) program are also discussed.

  6. An analysis of the situation and current trends in the management of construction projects at Los Alamos National Laboratory

    SciTech Connect

    Howell, G.

    1994-12-31

    At Los Alamos National Laboratory (LANL) there is a more to switch from reliance on rules to an expanded reliance on market forces, as evidenced by the facilities recharge program. This paper moves beyond the market/rule debate to argue that new approaches to project management are required. Managers at all levels in the LANL face contending demands as they are caught between immediate concerns and long term consequences, keeping track of the big picture and looking after the details. Management techniques appropriate for simple certain projects will be of limited value on complex uncertain projects built on tight schedules--no matter how market and rules are balanced in the larger organization. Thus the degree of complexity, uncertainty, and duration, should shape the choice of project management approaches. Single dimension simple buzz word solutions will do little good and may cause harm. This report reviews current situation and efforts underway to improve performance are reviewed. These efforts are shown to be useful but incomplete as significant improvement will both require altering and expanding how managers and the management system respond to contending demands.

  7. Active Flow Control of Lifting Surface With Flap-Current Activities and Future Directions

    NASA Technical Reports Server (NTRS)

    Ahmadi, G.; Marzocca, P.; Jha, R.; Alstorm, B.; Obied, S.; Kabir, P.; Shahrabi, A.

    2010-01-01

    The main objective is to develop effective control strategies for separation control of an airfoil with a single hinge flap. The specific objectives are: Develop an active control architecture for flow control around an airfoil with flap. Design, fabricate, a wind tunnel test of a high lift wing (with flap) with integrated actuators and sensors. Design, development and fabrication of synthetic jet actuators. Develop appropriate control strategy for application to the airfoil. Wind tunnel testing of the high lift wing at various angles of attack and flap positions with closed loop control.

  8. Soil Moisture Active Passive (SMAP) Calibration and Validation Plan and Current Activities

    NASA Technical Reports Server (NTRS)

    Jackson, T. J.; Cosh, M.; Bindlish, R.; Crow, W.; Colliander, A.; Njoku, E.; McDonald, K.; Kimball, J.; Belair, S.; Walker, J.; hide

    2010-01-01

    The primary objective of the SMAP calibration and validation (Cal/Val) program is demonstrating that the science requirements (product accuracy and bias) have been met over the mission life. This begins during pre-launch with activities that contribute to high quality products and establishing post-launch validation infrastructure and continues through the mission life. However, the major focus is on a relatively short Cal/Val period following launch. The general approach and elements of the SMAP Cal/Val plan will be described and along with details on several ongoing or recent field experiments designed to address both near- and long-term Cal/Val.

  9. Construct Validity Evidence for Single-Response Items to Estimate Physical Activity Levels in Large Sample Studies

    ERIC Educational Resources Information Center

    Jackson, Allen W.; Morrow, James R., Jr.; Bowles, Heather R.; FitzGerald, Shannon J.; Blair, Steven N.

    2007-01-01

    Valid measurement of physical activity is important for studying the risks for morbidity and mortality. The purpose of this study was to examine evidence of construct validity of two similar single-response items assessing physical activity via self-report. Both items are based on the stages of change model. The sample was 687 participants (men =…

  10. Construct Validity Evidence for Single-Response Items to Estimate Physical Activity Levels in Large Sample Studies

    ERIC Educational Resources Information Center

    Jackson, Allen W.; Morrow, James R., Jr.; Bowles, Heather R.; FitzGerald, Shannon J.; Blair, Steven N.

    2007-01-01

    Valid measurement of physical activity is important for studying the risks for morbidity and mortality. The purpose of this study was to examine evidence of construct validity of two similar single-response items assessing physical activity via self-report. Both items are based on the stages of change model. The sample was 687 participants (men =…

  11. Application of active quenching of second generation wire for current limiting

    NASA Astrophysics Data System (ADS)

    Solovyov, Vyacheslav F.; Li, Qiang

    2015-12-01

    Superconducting fault current limiters (SFCLs) are increasingly implemented in the power grid as a protection of substation equipment from fault currents. Resistive SFCLs are compact and light, however they are passively triggered and thus may not be sufficiently sensitive to respond to faults in the distribution grid. Here, we explore the prospect of adding an active management feature to a traditional resistive SFCL. A flexible radio-frequency coil, which is an integral part of the switching structure, acts as a triggering device. We show that the application of a short, 10 ms, burst of ac magnetic field during the fault triggers a uniform quench of the wire and significantly reduces the reaction time of the wire at low currents. The ac field burst generates a high density of normal zones, which merge into a continuous resistive region at a rate much faster than that of sparse normal zones created by the transport current alone.

  12. Application of active quenching of second generation wire for current limiting

    DOE PAGES

    Solovyov, Vyacheslav F.; Li, Qiang

    2015-10-19

    Superconducting fault current limiters (SFCL's) are increasingly implemented in the power grid as a protection of substation equipment from fault currents. Resistive SFCL's are compact and light, however they are passively triggered and thus may not be sufficiently sensitive to respond to faults in the distribution grid. Here, we explore the prospect of adding an active management feature to a traditional resistive SFCL. A flexible radio-frequency coil, which is an integral part of the switching structure, acts as a triggering device. We show that the application of a short, 10 ms, burst of ac magnetic field during the fault triggersmore » a uniform quench of the wire and significantly reduces the reaction time of the wire at low currents. The ac field burst generates a high density of normal zones, which merge into a continuous resistive region at a rate much faster than that of sparse normal zones created by the transport current alone.« less

  13. Application of active quenching of second generation wire for current limiting

    SciTech Connect

    Solovyov, Vyacheslav F.; Li, Qiang

    2015-10-19

    Superconducting fault current limiters (SFCL's) are increasingly implemented in the power grid as a protection of substation equipment from fault currents. Resistive SFCL's are compact and light, however they are passively triggered and thus may not be sufficiently sensitive to respond to faults in the distribution grid. Here, we explore the prospect of adding an active management feature to a traditional resistive SFCL. A flexible radio-frequency coil, which is an integral part of the switching structure, acts as a triggering device. We show that the application of a short, 10 ms, burst of ac magnetic field during the fault triggers a uniform quench of the wire and significantly reduces the reaction time of the wire at low currents. The ac field burst generates a high density of normal zones, which merge into a continuous resistive region at a rate much faster than that of sparse normal zones created by the transport current alone.

  14. TFT active image sensor with current-mode readout circuit for digital x-ray fluoroscopy

    NASA Astrophysics Data System (ADS)

    Safavian, Nader; Chaji, G. R.; Nathan, A.; Rowlands, J. A.

    2005-09-01

    In this paper, an innovative current-programmed, current-output active TFT image sensor suitable for real time x-ray imaging (fluoroscopy) using hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT) technology coupled with a transimpedance feedback column amplifier for pixel signal readout is presented. Simulation results show that this new TFT circuit can successfully compensate for variations in a-Si:H TFT characteristics under prolonged gate voltage stress. The readout is fast enough to fulfill the timing requirements of digital fluoroscopy. Dynamic effects such as charge injection, charge feed-through and drain-source voltage variation as well as additive noise of the pixel TFTs induce error on the output current of the pixel. To explore the dependence of this error on pixel parameters, concise analytical expressions are derived which can be used to reduce the amount of the output current error by proper pixel design.

  15. A current perspective on cancer immune therapy: step-by-step approach to constructing the magic bullet.

    PubMed

    D'Errico, Gabriele; Machado, Heather L; Sainz, Bruno

    2017-12-01

    Immunotherapy is the new trend in cancer treatment due to the selectivity, long lasting effects, and demonstrated improved overall survival and tolerance, when compared to patients treated with conventional chemotherapy. Despite these positive results, immunotherapy is still far from becoming the perfect magic bullet to fight cancer, largely due to the facts that immunotherapy is not effective in all patients nor in all cancer types. How and when will immunotherapy overcome these hurdles? In this review we take a step back to walk side by side with the pioneers of immunotherapy in order to understand what steps need to be taken today to make immunotherapy effective across all cancers. While early scientists, such as Coley, elicited an unselective but effective response against cancer, the search for selectivity pushed immunotherapy to the side in favor of drugs focused on targeting cancer cells. Fortunately, the modern era would revive the importance of the immune system in battling cancer by releasing the brakes or checkpoints (anti-CTLA-4 and anti-PD-1/PD-L1) that have been holding the immune system at bay. However, there are still many hurdles to overcome before immunotherapy becomes a universal cancer therapy. For example, we discuss how the redundant and complex nature of the immune system can impede tumor elimination by teeter tottering between different polarization states: one eliciting anti-cancer effects while the other promoting cancer growth and invasion. In addition, we highlight the incapacity of the immune system to choose between a fight or repair action with respect to tumor growth. Finally we combine these concepts to present a new way to think about the immune system and immune tolerance, by introducing two new metaphors, the "push the accelerator" and "repair the car" metaphors, to explain the current limitations associated with cancer immunotherapy.

  16. Principles of sustainable development of the territory and priorities of architectural and urban construction activity

    NASA Astrophysics Data System (ADS)

    Dontsov, Dmitry; Yushkova, Natalia

    2017-01-01

    The paper is aimed at detecting conceptual conflicts within the architectural and urban construction activity (AUCA), defining their reasons and substantiating ways to decrease adverse effects they caused. Methods of causes and effects analyses are used, as well as evolutional and comparative analyses. They allow defining the laws to form activity model in modern environment, whose elements are ranked. Relevance of the paper is based on defining scientific and theoretical grounds of necessity to improve methodology of AUCA via its adaption to the imperatives of state management. System analyses enabled to prove practicability of considering factors of institution environment for reorganization of the model of AUCA, which provide the fullest implementation of sustainable development principles. It was proved that territorial planning is not only the leading type of AUCA, but also integrator for functioning structures of state management within planning of social and economic development. As main result of the paper consist in detection of the perspective ways for evolution of modern methodology due to increasing interdisciplinary aspect leading to the qualitative renewal of territorial management principles.

  17. Inhibition of the hyperpolarization-activated current (if) of rabbit SA node myocytes by niflumic acid.

    PubMed

    Accili, E A; DiFrancesco, D

    1996-03-01

    The effects of the amphiphilic substance niflumic acid (NFA) were examined in myocytes isolated from the sino-atrial node of the rabbit heart. NFA (50 and 500 microM), for 30-60 s, produced a reversible negative chronotropic effect by reducing the rate of diastolic depolarization, suggesting an inhibitory effect on the hyperpolarization-activated pacemaker current (if). NFA (from 0.05 to 500 microM) inhibited if by modifying the current kinetics, without alteration of the conductance. This was shown by evidence indicating that: (1) NFA inhibited if during hyperpolarizing pulses to the mid-point of if activation but not at fully activating voltages; (2) the slope and reversal potential of the fully activated current/voltage (I/V) relation were not altered by NFA, indicating no change in slope conductance or ion selectivity; and (3) hyperpolarizing ramp protocols confirmed the lack of action of 50 microM NFA on the fully activated current and a shift of approximately -8 mV. Although similar to inhibition by acetylcholine (ACh), inhibition by NFA was only partly additive with the action of ACh and was not altered by atropine or pertussis toxin, both of which eliminated the action of ACh. The effect of NFA was present after stimulation of adenylate cyclase by forskolin and after inhibition of phosphodiesterase by isobutylmethylxanthine (IBMX). In cell-attached patch measurements, NFA applied externally did not affect if measured in the patch. Finally, application of NFA to the cytoplasmic side of excised patches did not alter the current in the absence or presence of adenosine 3',5'-cyclic monophosphate (cAMP). These results suggest an external, membrane-delimited action of NFA on if.

  18. Local anaesthetics block hyperpolarization-activated inward current in rat small dorsal root ganglion neurones

    PubMed Central

    Bischoff, Ulrike; Bräu, Michael E; Vogel, Werner; Hempelmann, Gunter; Olschewski, Andrea

    2003-01-01

    Hyperpolarizing voltage steps evoke slowly activating inward currents in a variety of neurones and in cardiac cells. This hyperpolarization-activated inward current (Ih) is thought to play a significant role in cell excitability, firing frequency, or in setting of the resting membrane potential in these cells. We studied the effects of lidocaine, mepivacaine, QX-314 and bupivacaine as well as its enantiomers on Ih in the membrane of dorsal root ganglion neurones (DRG). The patch-clamp technique was applied to small dorsal root ganglion neurones identified in 200 μM thin slices of young rat DRGs. Under voltage-clamp conditions, the whole-cell Ih current was recorded in the presence of different concentrations of the local anaesthetics. In current-clamp mode the resting membrane potential and the voltage response of DRG neurones to injected current pulses were investigated. Ih was reversibly blocked by bupivacaine, lidocaine and mepivacaine applied externally in clinically relevant concentrations. Concentration–response curves gave half-maximum inhibiting concentrations of 55, 99 and 190 μM, respectively. Bupivacaine block of the Ih current was not stereoselective. No significant effect was observed when QX-314 was applied to the external surface of the membrane. In current-clamp experiments 60 μM bupivacaine slightly hyperpolarized the membrane. The membrane stimulation by low-amplitude current pulses in the presence of bupivacaine showed an increase of the hyperpolarizing responses. Our findings suggest an important role of the Ih-block by local anaesthetics in the complex mechanism of drug action during epidural and spinal anaesthesia. PMID:12890706

  19. Contribution of occupational factors to current smoking among active-duty U.S. Navy careerists.

    PubMed

    Cunradi, Carol B; Moore, Roland S; Ames, Genevieve

    2008-03-01

    Rates of cigarette smoking among active-duty U.S. military personnel remain elevated, ranging from 23% among Air Force personnel to 38% among Army personnel. The purpose of this study was to estimate the contribution of occupational factors to current smoking and heavy smoking among a sample of Navy careerists (those with at least 7 years of military service), and to determine if gender moderates these associations. Participants in the study (n = 2,922) were randomly recruited within over-sampled strata of women and racial/ethnic minorities, and voluntarily completed confidential self-administered questionnaires on drinking, smoking, demographic, and occupational factors during 2001-2002. Approximately 23% of study participants reported current smoking; 9% reported heavy smoking. Multivariate logistic regression models were developed to estimate the contribution of occupational factors to current smoking and heavy smoking. The results indicated that careerists in the enlisted ranks were significantly more likely to be current smokers and heavy smokers compared with careerist officers. In addition, those who were deployed at sea were significantly more likely to report current smoking compared with those not currently deployed at sea. Mean daily ounces of alcohol were also significantly associated with likelihood of current and heavy smoking. Gender did not modify the association between occupational factors and smoking. Because aspects of the work environment are potentially modifiable, understanding the role of occupational factors vis-à-vis smoking can aid in smoking prevention and cessation efforts within the military.

  20. Current Steering to Control the Volume of Tissue Activated During Deep Brain Stimulation

    PubMed Central

    Butson, Christopher R.; McIntyre, Cameron C.

    2009-01-01

    Background Over the last two decades, deep brain stimulation (DBS) has become a recognized and effective clinical therapy for numerous neurological conditions. Since its inception, clinical DBS technology has progressed at a relatively slow rate; however, advances in neural engineering research have the potential to improve DBS systems. One such advance is the concept of current steering, or the use of multiple stimulation sources to direct current flow through targeted regions of brain tissue. Objective The goals of this study were to develop a theoretical understanding of the effects of current steering in the context of DBS, and use that information to evaluate the potential utility of current steering during stimulation of the subthalamic nucleus. Methods We used finite element electric field models, coupled to multi-compartment cable axon models, to predict the volume of tissue activated (VTA) by DBS as a function of the stimulation parameter settings. Results Balancing current flow through adjacent cathodes increased the VTA magnitude, relative to monopolar stimulation, and current steering enabled us to sculpt the shape of the VTA to fit a given anatomical target. Conclusions These results provide motivation for the integration of current steering technology into clinical DBS systems, thereby expanding opportunities to customize DBS to individual patients, and potentially enhancing therapeutic efficacy. PMID:19142235

  1. Voltage-dependent calcium and calcium-activated potassium currents of a molluscan photoreceptor.

    PubMed

    Alkon, D L; Farley, J; Sakakibara, M; Hay, B

    1984-11-01

    Two-microelectrode voltage clamp studies were performed on the somata of Hermissenda Type B photoreceptors that had been isolated by axotomy from all synaptic interaction as well as any impulse-generating (i.e., active) membrane. In the presence of 2-10 mM 4-aminopyridine (4-AP) and 100 mM tetraethylammonium ion (TEA), which eliminated two previously described voltage-dependent potassium currents (IA and the delayed rectifier), a voltage-dependent outward current was apparent in the steady state responses to command voltage steps more positive than -40 mV (absolute). This current increased with increasing external Ca++. The magnitude of the outward current decreased and an inward current became apparent following EGTA injection. Substitution of external Ba++ for Ca++ also made the inward current more apparent. This inward current, which was almost eliminated after being exposed for approximately 5 min to a solution in which external Ca++ was replaced with Cd++, was maximally activated at approximately 0 mV. Elevation of external potassium allowed the calcium (ICa++) and calcium-dependent K+ (IC) currents to be substantially separated. Command pulses to 0 mV elicited maximal ICa++ but no IC because no K+ currents flowed at their new reversal potential (0 mV) in 300 mM K+. At a holding potential of -60 mV, which was now more negative than the potassium equilibrium potential, EK+, in 300 mM K+, IC appeared as an inward tail current after positive command steps. The voltage dependence of ICa++ was demonstrated with positive steps in 100 mM Ba++, 4-AP, and TEA. Other data indicated that in 10 mM Ca++, IC underwent pronounced and prolonged inactivation whereas ICa++ did not. When the photoreceptor was stimulated with a light step (with the membrane potential held at -60 mV), there was also a prolonged inactivation of IC. In elevated external Ca++, ICa++ also showed similar inactivation. These data suggest that IC may undergo prolonged inactivation due to a direct effect

  2. Voltage-dependent calcium and calcium-activated potassium currents of a molluscan photoreceptor.

    PubMed Central

    Alkon, D L; Farley, J; Sakakibara, M; Hay, B

    1984-01-01

    Two-microelectrode voltage clamp studies were performed on the somata of Hermissenda Type B photoreceptors that had been isolated by axotomy from all synaptic interaction as well as any impulse-generating (i.e., active) membrane. In the presence of 2-10 mM 4-aminopyridine (4-AP) and 100 mM tetraethylammonium ion (TEA), which eliminated two previously described voltage-dependent potassium currents (IA and the delayed rectifier), a voltage-dependent outward current was apparent in the steady state responses to command voltage steps more positive than -40 mV (absolute). This current increased with increasing external Ca++. The magnitude of the outward current decreased and an inward current became apparent following EGTA injection. Substitution of external Ba++ for Ca++ also made the inward current more apparent. This inward current, which was almost eliminated after being exposed for approximately 5 min to a solution in which external Ca++ was replaced with Cd++, was maximally activated at approximately 0 mV. Elevation of external potassium allowed the calcium (ICa++) and calcium-dependent K+ (IC) currents to be substantially separated. Command pulses to 0 mV elicited maximal ICa++ but no IC because no K+ currents flowed at their new reversal potential (0 mV) in 300 mM K+. At a holding potential of -60 mV, which was now more negative than the potassium equilibrium potential, EK+, in 300 mM K+, IC appeared as an inward tail current after positive command steps. The voltage dependence of ICa++ was demonstrated with positive steps in 100 mM Ba++, 4-AP, and TEA. Other data indicated that in 10 mM Ca++, IC underwent pronounced and prolonged inactivation whereas ICa++ did not. When the photoreceptor was stimulated with a light step (with the membrane potential held at -60 mV), there was also a prolonged inactivation of IC. In elevated external Ca++, ICa++ also showed similar inactivation. These data suggest that IC may undergo prolonged inactivation due to a direct effect

  3. Sodium-activated potassium channels are functionally coupled to persistent sodium currents.

    PubMed

    Hage, Travis A; Salkoff, Lawrence

    2012-02-22

    We report a novel coupled system of sodium-activated potassium currents (I(KNa)) and persistent sodium currents (I(NaP)), the components of which are widely distributed throughout the brain. Its existence and importance has not been previously recognized. Although I(KNa) was known to exist in many cell types, the source of Na(+) which activates I(KNa) remained a mystery. We now show in single membrane patches generated from the somas of rat neurons that sodium influx through I(NaP) is sufficient for activation of K(Na) channels, without substantial contribution from the transient sodium current or bulk [Na(+)](i). I(NaP) was found to be active at cell membrane resting potentials, a finding that may explain why I(KNa) can be evoked from negative holding potentials. These results show an unanticipated role for I(NaP) in activating a negative feedback system countering the excitable effects I(NaP); the interrelatedness of I(NaP) and I(KNa) suggests new ways neurons can tune their excitability.

  4. Episodic specificity induction impacts activity in a core brain network during construction of imagined future experiences

    PubMed Central

    Madore, Kevin P.; Szpunar, Karl K.; Addis, Donna Rose; Schacter, Daniel L.

    2016-01-01

    Recent behavioral work suggests that an episodic specificity induction—brief training in recollecting the details of a past experience—enhances performance on subsequent tasks that rely on episodic retrieval, including imagining future experiences, solving open-ended problems, and thinking creatively. Despite these far-reaching behavioral effects, nothing is known about the neural processes impacted by an episodic specificity induction. Related neuroimaging work has linked episodic retrieval with a core network of brain regions that supports imagining future experiences. We tested the hypothesis that key structures in this network are influenced by the specificity induction. Participants received the specificity induction or one of two control inductions and then generated future events and semantic object comparisons during fMRI scanning. After receiving the specificity induction compared with the control, participants exhibited significantly more activity in several core network regions during the construction of imagined events over object comparisons, including the left anterior hippocampus, right inferior parietal lobule, right posterior cingulate cortex, and right ventral precuneus. Induction-related differences in the episodic detail of imagined events significantly modulated induction-related differences in the construction of imagined events in the left anterior hippocampus and right inferior parietal lobule. Resting-state functional connectivity analyses with hippocampal and inferior parietal lobule seed regions and the rest of the brain also revealed significantly stronger core network coupling following the specificity induction compared with the control. These findings provide evidence that an episodic specificity induction selectively targets episodic processes that are commonly linked to key core network regions, including the hippocampus. PMID:27601666

  5. Episodic specificity induction impacts activity in a core brain network during construction of imagined future experiences.

    PubMed

    Madore, Kevin P; Szpunar, Karl K; Addis, Donna Rose; Schacter, Daniel L

    2016-09-20

    Recent behavioral work suggests that an episodic specificity induction-brief training in recollecting the details of a past experience-enhances performance on subsequent tasks that rely on episodic retrieval, including imagining future experiences, solving open-ended problems, and thinking creatively. Despite these far-reaching behavioral effects, nothing is known about the neural processes impacted by an episodic specificity induction. Related neuroimaging work has linked episodic retrieval with a core network of brain regions that supports imagining future experiences. We tested the hypothesis that key structures in this network are influenced by the specificity induction. Participants received the specificity induction or one of two control inductions and then generated future events and semantic object comparisons during fMRI scanning. After receiving the specificity induction compared with the control, participants exhibited significantly more activity in several core network regions during the construction of imagined events over object comparisons, including the left anterior hippocampus, right inferior parietal lobule, right posterior cingulate cortex, and right ventral precuneus. Induction-related differences in the episodic detail of imagined events significantly modulated induction-related differences in the construction of imagined events in the left anterior hippocampus and right inferior parietal lobule. Resting-state functional connectivity analyses with hippocampal and inferior parietal lobule seed regions and the rest of the brain also revealed significantly stronger core network coupling following the specificity induction compared with the control. These findings provide evidence that an episodic specificity induction selectively targets episodic processes that are commonly linked to key core network regions, including the hippocampus.

  6. Reversible Redox Activity in Multicomponent Metal-Organic Frameworks Constructed from Trinuclear Copper Pyrazolate Building Blocks.

    PubMed

    Tu, Binbin; Pang, Qingqing; Xu, Huoshu; Li, Xiaomin; Wang, Yulin; Ma, Zhen; Weng, Linhong; Li, Qiaowei

    2017-06-14

    Inorganic functionalization of metal-organic frameworks (MOFs), such as incorporation of multiple inorganic building blocks with distinct metals into one structure and further modulation of the metal charges, endows the porous materials with significant properties toward their applications in catalysis. In this work, by an exploration of the role of 4-pyrazolecarboxylic acid (H2PyC) in the formation of trinuclear copper pyrazolate as a metalloligand in situ, four new MOFs with multiple components in order were constructed through one-pot synthesis. This metalloligand strategy provides multicomponent MOFs with new topologies (tub for FDM-4 and tap for FDM-5) and is also compatible with a second organic linker for cooperative construction of complex MOFs (1,4-benzenedicarboxylic acid for FDM-6 and 2,6-naphthalenedicarboxylic acid for FDM-7). The component multiplicity of these MOFs originates from PyC's ability to separate Cu and Zn on the basis of their differentiated binding affinities toward pyrazolate and carboxylate. These MOFs feature reversible and facile redox transformations between Cu(I)3(PyC)3 and Cu(II)3(μ-OH)(PyC)3(OH)3 without altering the connecting geometries of the units, thus further contributing to the significant catalytic activities in the oxidation of CO and aromatic alcohols and the decomposition of H2O2. This study on programming multiple inorganic components into one framework and modulating their electronic structures is an example of functionalizing the inorganic units of MOFs with a high degree of control.

  7. Analysis of G-protein-activated inward rectifying K(+) (GIRK) channel currents upon GABAB receptor activation in rat supraoptic neurons.

    PubMed

    Harayama, Nobuya; Kayano, Tomohiko; Moriya, Taiki; Kitamura, Naoki; Shibuya, Izumi; Tanaka-Yamamoto, Keiko; Uezono, Yasuhito; Ueta, Yoichi; Sata, Takeyoshi

    2014-12-03

    While magnocellular neurons in the supraoptic nucleus (SON) possess rich Gi/o-mediated mechanisms, molecular and cellular properties of G-protein-activated inwardly rectifying K(+) (GIRK) channels have been controversial. Here, properties of GIRK channels are examined by RT-PCR and whole-cell patch-clamp techniques in rat SON neurons. Patch clamp experiments showed that the selective GABAB agonist, baclofen, enhanced currents in a high K(+) condition. The baclofen-enhanced currents exhibited evident inward rectification and were blocked by the selective GABAB antagonist, CGP55845A, the IRK channel blocker, Ba(2+), and the selective GIRK channel blocker, tertiapin, indicating that baclofen activates GIRK channels via GABAB receptors. The GIRK currents were abolished by N-ethylmaleimide pretreatment, and prolonged by GTPγS inclusion in the patch pipette, suggesting that Gi/o proteins are involved. RT-PCR analysis revealed mRNAs for all four GIRK 1-4 channels and for both GABABR1 and GABABR2 receptors in rat SON. However, the concentration-dependency of the baclofen-induced activation of GIRK currents had an EC50 of 110 µM, which is about 100 times higher than that of baclofen-induced inhibition of voltage-dependent Ca(2+) channels. Moreover, baclofen caused no significant changes in the membrane potential and the firing rate. These results suggest that although GIRK channels can be activated by GABAB receptors via the Gi/o pathway, this occurs at high agonist concentrations, and thus may not be a physiological mechanism regulating the function of SON neurons. This property that the membrane potential receives little influence from GIRK currents seems to be uncommon for CNS neurons possessing rich Gi/o-coupled receptors, and could be a special feature of rat SON neurons. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Environmental acceptability of beneficial use of waste as construction material--state of knowledge, current practices and future developments in Europe and in France.

    PubMed

    Chateau, Laurent

    2007-01-31

    Since a decade, numerous industrial and public initiatives have been launched in order to make knowledge, practices and mentalities evolve in relation to the acceptability of using waste instead of raw material as construction product. The objectives of these initiatives have been to evaluate current practices and to make new solutions and beneficial use channels emerge. At the same time scientific and standardisation communities have developed methodologies and tools to fit with the assessment needs expressed by industrialists and public decision-makers. In spite of that, some factors, some of them being cross-linked, make the perpetuation of beneficial use channels or even the concretisation of research projects difficult. To cope with this situation, in the framework of sustainable development applied to natural and alternative material, the French Directorate of Road has launched a project aiming at providing public contracting authorities with a document gathering both technical and environmental requirements that they can prescribe in public market tender calls to promote the use of waste and out-of-technical-specifications-material. This paper deals with the presentation of this project focusing more specifically on the approach to assess both technical and environmental acceptability of waste and out-of-technical-specifications-material to be used as alternative material in road construction in France. The current European situation is first described and this paper finally discusses briefly the other key aspects--than environmental acceptability--that have to be taken into account to succeed waste beneficial use.

  9. Coronal Hole-Active Region-Current Sheet (CHARCS) Association with Intense Interplanetary and Geomagnetic Activity

    NASA Technical Reports Server (NTRS)

    Gonzalez, W. D.; Tsurutani, B. T.; McIntosh, P. S.; Gonzalez, A. L.

    1996-01-01

    Intense geomagnetic storms (Dstactive regions(flares and/or filament eruptions) ocurring close to the streamer belt and to growing low altitude coronal holes. It is also shown that such type of coronal holes had a dual-peak solar cycle distribution during solar cycle 21, similar to that previously reported for the above mentioned interplanetary and geomagnetic phenomena.

  10. Current standards, variations, and pitfalls for the determination of constitutive TSHR activity in vitro.

    PubMed

    Mueller, Sandra; Jaeschke, Holger; Paschke, Ralf

    2010-01-01

    Constitutively activating mutations of the TSHR are the major cause for nonautoimmune hyperthyroidism, which is based on ligand independent, permanent receptor activation. Several reports have highlighted the difficulties to determine whether a TSHR mutation is constitutively active or not especially for borderline cases with only a slight increase of the basal cAMP activity. Current methods to precisely classify such mutants as constitutively active or not, are limited. In some cases, in vitro characterization of TSHR mutants has led to false positive conclusions regarding constitutive TSHR activity and subsequently the molecular origin of hyperthyroidism. For characterization of constitutive TSHR activity, a particular point to consider is that basal receptor activity tightly correlates with the receptor number expressed on the cell surface. Therefore, a comparison of the receptors basal activity in relation to the wild type is only possible with determination of the receptor cell surface expression. Thus, the experimental approaches to determine constitutive TSHR activity should consider the receptor's cell surface expression. We here provide a description of three methods for the determination of constitutive TSHR activity: (A) the evaluation of constitutive TSHR activity under conditions of equal receptor expression; (B) computation of the specific constitutive activity; and (C) the linear regression analysis (LRA). To date, LRA is the best experimental approach to characterize the mutant's basal activity as a function of TSHR cell surface expression. This approach utilizes a parallel measurement of basal cAMP values and receptor cell surface expression and therefore provides a more reliable decision with respect to the presence or absence of constitutive activity.

  11. [Static volt-ampere characteristics of biologically active human skin currents].

    PubMed

    Nikolaev, E V; Podlepetskiĭ, B I; Stepanenko, I P

    1980-01-01

    Results are presented of measuring static voltage characteristics of biologically active sites Xe-gy at various pressure of the measuring electrode on the skin. It has been shown that under other equal conditions conductivity of the active sites is 3 and more times higher than that of inactive sites in the whole range of the applied pressures. The current-voltage characteristics of biologically active sites are non-linear and have a region of reversible break-down on their inverse branch. With the currents higher than 200 divided by 300 muA an irreversible break-down of the site is formed, after which conductivity increases more than by an order.

  12. Changes of extracellular potassium activity induced by electric current through brain tissue in the rat.

    PubMed Central

    Gardner-Medwin, A R; Nicholson, C

    1983-01-01

    Ion-selective micro-electrodes have been used to measure K+ and Ca2+ activity changes in extracellular space beneath the surface of the neocortex and cerebellar cortex during current flow across the tissue surface in anaesthetized rats. Inward currents produced decreases of [K+]o and outward currents produced increases, with insignificant changes in [Ca2+]o. Changes of [K+]o were largest just under the surface of the tissue, but were detectable down to depths of ca. 1 mm. With appropriate sitting of electrodes in the cerebellar cortex, currents of 22 microA mm-2 for 400 sec produced changes averaging -42% for inward current and +66% for outward current. The [K+]o changes near the surface were most rapid immediately after the onset of current and more gradual after some tens of seconds. Deeper within the tissue the rate of change was more uniform and after the end of stimulation the return to base line was slower. The amplitude, depth dependence and time course of the [K+]o changes were in reasonable agreement with the results calculated for a model in which K+ moves partly through extracellular space but primarily through membranes and cytoplasm within the tissue. The [K+]o changes were not attributable to variations in neuronal activity, although unit activity could be modified by current, since alternating currents failed to produce [K+]o changes and neither 0.1 mM-tetrodotoxin nor 5 mM-Mn2+ abolished the changes. The [K+]o changes were not abolished by topically applied ouabain (4 X 10(-4) M), 2,4-dinitrophenol (20 mM) or iodoacetate (10 mM), or by asphyxiation. Consequently the [K+]o changes are not dependent on metabolism. The data suggest that there is a selective mechanism for passive K+ transport in an electrochemical gradient within brain tissue that results in higher K+ fluxes than could be supported by ionic mobility in the extracellular fluid. This mechanism exists not only at the surface but within the brain parenchyma and may involve current flow

  13. Predicting the activity phase of a follower neuron with A-current in an inhibitory network.

    PubMed

    Zhang, Yu; Bose, Amitabha; Nadim, Farzan

    2008-09-01

    The transient potassium A-current is present in most neurons and plays an important role in determining the timing of action potentials. We examine the role of the A-current in the activity phase of a follower neuron in a rhythmic feed-forward inhibitory network with a reduced three-variable model and conduct experiments to verify the usefulness of our model. Using geometric analysis of dynamical systems, we explore the factors that determine the onset of activity in a follower neuron following release from inhibition. We first analyze the behavior of the follower neuron in a single cycle and find that the phase plane structure of the model can be used to predict the potential behaviors of the follower neuron following release from inhibition. We show that, depending on the relative scales of the inactivation time constant of the A-current and the time constant of the recovery variable, the follower neuron may or may not reach its active state following inhibition. Our simple model is used to derive a recursive set of equations to predict the contribution of the A-current parameters in determining the activity phase of a follower neuron as a function of the duration and frequency of the inhibitory input it receives. These equations can be used to demonstrate the dependence of activity phase on the period and duty cycle of the periodic inhibition, as seen by comparing the predictions of the model with the activity of the pyloric constrictor (PY) neurons in the crustacean pyloric network.

  14. Modulation by different GABAB receptor types of voltage-activated calcium currents in rat thalamocortical neurones.

    PubMed Central

    Guyon, A; Leresche, N

    1995-01-01

    1. The effects of the GABAB receptor agonist baclofen on the voltage-dependent Ca2+ currents were studied in rat thalamocortical neurones with the use of whole cell voltage-clamp recordings in brain slices. 2. The contribution of N-, L- and P-types of Ca2+ channels to the total high voltage-activated Ca2+ (HVA Ca2+) current was assessed by the use of omega-conotoxin, nifedipine and omega-agatoxin IVA, respectively. No P-type current could be detected. Thus, the HVA Ca2+ current contained an N- and an L-type current (23 and 15% of the total current, respectively) and a residual current, which will be referred to as the 'R' component. 3. Baclofen (1-50 microM) had no effect on the low voltage-activated (LVA) Ca2+ current (IT). 4. At low concentrations (0.5-10 microM), baclofen decreased the HVA Ca2+ currents by about 10-20% without a marked modification on the kinetics, whereas 50 microM baclofen decreased the HVA Ca2+ currents by about 40% with a pronounced slowing down of the kinetics. 5. The 10-20% decrease of the total HVA Ca2+ currents produced by the low concentrations of baclofen occurred as the result of a 30% block of the 'R' component. The additional decrease observed with the dose of 50 microM was due to a full block of the N-type current. The L-type was unaffected by baclofen. 6. The effect of baclofen on the total HVA Ca2+ current was partially blocked by GABAB receptor antagonists indicating that it occurred through stimulation of GABAB receptors. 7. The effect of baclofen on the N-type current was abolished by CGP 35348 (100 microM) and CGP 55845A (100 nM). The effect on the 'R' component was also antagonized by CGP 55845A (100 nM) although with a lower potency, but was not blocked by CGP 35348 (100 microM). 8. We conclude that the effects of baclofen on the various components of the HVA Ca2+ currents occur through different types of GABAB receptors. One receptor has a high affinity for baclofen (i.e. saturated by concentrations as low as 0.5 micro

  15. Hyperpolarization-Activated Current Induces Period-Doubling Cascades and Chaos in a Cold Thermoreceptor Model.

    PubMed

    Xu, Kesheng; Maidana, Jean P; Caviedes, Mauricio; Quero, Daniel; Aguirre, Pablo; Orio, Patricio

    2017-01-01

    In this article, we describe and analyze the chaotic behavior of a conductance-based neuronal bursting model. This is a model with a reduced number of variables, yet it retains biophysical plausibility. Inspired by the activity of cold thermoreceptors, the model contains a persistent Sodium current, a Calcium-activated Potassium current and a hyperpolarization-activated current (Ih) that drive a slow subthreshold oscillation. Driven by this oscillation, a fast subsystem (fast Sodium and Potassium currents) fires action potentials in a periodic fashion. Depending on the parameters, this model can generate a variety of firing patterns that includes bursting, regular tonic and polymodal firing. Here we show that the transitions between different firing patterns are often accompanied by a range of chaotic firing, as suggested by an irregular, non-periodic firing pattern. To confirm this, we measure the maximum Lyapunov exponent of the voltage trajectories, and the Lyapunov exponent and Lempel-Ziv's complexity of the ISI time series. The four-variable slow system (without spiking) also generates chaotic behavior, and bifurcation analysis shows that this is often originated by period doubling cascades. Either with or without spikes, chaos is no longer generated when the Ih is removed from the system. As the model is biologically plausible with biophysically meaningful parameters, we propose it as a useful tool to understand chaotic dynamics in neurons.

  16. cAMP-activated chloride currents in amphibian retinal pigment epithelial cells.

    PubMed Central

    Hughes, B A; Segawa, Y

    1993-01-01

    1. The effect of cAMP on whole-cell currents in isolated retinal pigment epithelial (RPE) cells of the bullfrog and marine toad was investigated by means of the perforated patch clamp technique. 2. Superfusing cells with either cAMP or forskolin led to the development of a time-independent current that had a linear current-voltage (I-V) relationship. The reversal potential of (Vrev) of the cAMP-activated current was unaffected by the removal of either Na+ or HCO3- from the external and internal solutions or by the addition of extracellular barium, but it was near the Cl- equilibrium potential (ECl) over a wide range of extracellular Cl- concentrations, suggesting the presence of a Cl(-)-selective channel. 3. The anion permeability sequence of the cAMP-activated conductance calculated from biionic reversal potentials was NO3- = I- > Br- > Cl- >> HCO3- > methanesulphonate. 4. The conductance was blocked by a variety of Cl- transport inhibitors, including 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS), 4,4'-dinitro-2,2'- stilbene disulphonic acid (DNDS), frusemide, N-phenylanthranilic acid (DPC) and niflumic acid. 5. The present study demonstrates that cAMP activates a Cl(-)-selective channel that most probably resides in the basolateral membrane. PMID:8410715

  17. Hyperpolarization-Activated Current Induces Period-Doubling Cascades and Chaos in a Cold Thermoreceptor Model

    PubMed Central

    Xu, Kesheng; Maidana, Jean P.; Caviedes, Mauricio; Quero, Daniel; Aguirre, Pablo; Orio, Patricio

    2017-01-01

    In this article, we describe and analyze the chaotic behavior of a conductance-based neuronal bursting model. This is a model with a reduced number of variables, yet it retains biophysical plausibility. Inspired by the activity of cold thermoreceptors, the model contains a persistent Sodium current, a Calcium-activated Potassium current and a hyperpolarization-activated current (Ih) that drive a slow subthreshold oscillation. Driven by this oscillation, a fast subsystem (fast Sodium and Potassium currents) fires action potentials in a periodic fashion. Depending on the parameters, this model can generate a variety of firing patterns that includes bursting, regular tonic and polymodal firing. Here we show that the transitions between different firing patterns are often accompanied by a range of chaotic firing, as suggested by an irregular, non-periodic firing pattern. To confirm this, we measure the maximum Lyapunov exponent of the voltage trajectories, and the Lyapunov exponent and Lempel-Ziv's complexity of the ISI time series. The four-variable slow system (without spiking) also generates chaotic behavior, and bifurcation analysis shows that this is often originated by period doubling cascades. Either with or without spikes, chaos is no longer generated when the Ih is removed from the system. As the model is biologically plausible with biophysically meaningful parameters, we propose it as a useful tool to understand chaotic dynamics in neurons. PMID:28344550

  18. Characteristics of chloride currents activated by noradrenaline in rabbit ear artery cells.

    PubMed

    Amédée, T; Large, W A; Wang, Q

    1990-09-01

    1. Responses to noradrenaline were studied in isolated rabbit ear artery cells with the nystatin method of whole-cell patch-clamp recording. With this technique it was possible to obtain reproducible responses to noradrenaline which was not possible with traditional whole-cell recording. 2. With NaCl as the major constituent of the bathing solution (potassium-free pipette and external solutions) the reversal potential (Er) of the noradrenaline-evoked current was about 0 mV. When external chloride was replaced by thiocyanate, iodide, nitrate and bromide, Er was shifted to more negative potentials which indicates that a chloride conductance increase contributes to the current activated by noradrenaline. 3. When sodium was substituted by Tris, N-methyl-D-glucamine, choline or barium, Er of the noradrenaline-evoked current did not alter. This result suggests that a cation conductance is not implicated in the response to noradrenaline recorded with the nystatin method of whole-cell recording. 4. The chloride current activated by noradrenaline was blocked by the selective alpha 1-adrenoceptor antagonist prazosin but was not affected by the alpha 2-adrenoceptor antagonist yohimbine. 5. When cells were exposed to zero calcium bathing solutions the amplitude of the current elicited by noradrenaline was unaffected when measured within 1-2 min in zero calcium conditions. Continued exposure to 0 Ca + 1 mM-EGTA solution reversibly abolished the chloride current to noradrenaline. 6. In the presence of caffeine, which releases Ca2+ from internal stores and itself induced an inward current (at a holding potential of -50 mV), noradrenaline did not elicit a current. These data suggest that the chloride current evoked by noradrenaline results from an increase in intracellular concentration of calcium derived from internal stores. 7. The chloride channel blocking agents 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS; 0.5 mM) and furosemide (0.5 mM) produced partial

  19. The Effect of Water on the Flow of Stress-Activated Electric Currents through Rocks

    NASA Astrophysics Data System (ADS)

    Jahoda, A. M.; Cyr, G. G.; Dahlgren, R.; Freund, F. T.

    2011-12-01

    When igneous or high-grade metamorphic rocks are subjected to deviatoric stresses, dormant defects in the matrix of common rock-forming minerals become activated. These defects consist of pairs of oxygen anions in the 1- valence state, e.g. peroxy links such as O3Si-OO-SiO3. When a peroxy bond breaks, O3Si-O:O-SiO3, an electron is transferred from a neighboring O2- causing the donor oxygen, now O-, to turn into a defect electron, also known as a positive hole, that can propagate as a highly mobile positive charge through the rocks1. The current outflow is driven by the battery potential that builds up during this process. The question is how this electric current through rocks is affected by water. When positive holes flow into bulk water, they oxidize H2O to H2O2 and are thereby consumed2. This electrochemical reaction is driven by the potential drop across the rock-water interface. However, no such potential drop occurs across water that fills pores inside the rocks along the path of the electronic charge carriers. We present evidence that the presence of water in the pore space does indeed not "kill" the current flow. This observation leads to the conclusion that stress-activated positive hole currents should be able to flow through water-saturated rocks maybe as well as, possibly even better than through dry rocks. 1 Freund, F. T., et al.: Electric currents streaming out of stressed igneous rocks - A step towards understanding pre-earthquake low frequency EM emissions, Phys. Chem. Earth, 2006, 31, 389-396. 2 Balk, M., et al.: Oxidation of water to hydrogen peroxide at the rock-water interface due to stress-activated electric currents in rocks, Earth Planet. Sci. Lett. 2009, 283, 87-92

  20. Preface: Special Session SpS7 The impact hazard: current activities and future plans

    NASA Astrophysics Data System (ADS)

    Montmerle, Thierry

    2015-03-01

    In 2012, at the time of the Beijing GA, two decades had passed since the publication of the Spaceguard Report. Time has not passed in vain for the subject of NEO-related hazards, and we are currently in a totally different situation than in the early nineties. The amount of work done, and the level of awareness of the underlying problems, have both risen to such a level that a re-assessment by the astronomical community of its rôle and involvement was in order, and the GA Special Session 7 ``The impact hazard: current activities and future plans'' was aimed exactly at that.

  1. The Current Driven Kink Instability and its Relationship to Delta-Spot Active Regions

    NASA Astrophysics Data System (ADS)

    Linton, Mark George

    The current driven kink instability may be the cause of both the unusual morphology of solar δ-spot active regions and the tendency of these regions to be significantly more flare active than most active regions. We investigate the current driven kink instability of flux tubes in the solar interior both with a linear stability analysis and with nonlinear MHD simulations. The linear analysis shows that there is a critical twist, which depends on the axial magnetic field profile, that a flux tube needs to become kink unstable. This critical twist decreases as the tube expands, so twisted flux tubes will become increasingly unstable as they rise through the convection zone. The nonlinear simulations show that a twisted tube excited by a single unstable kink mode will evolve to a helical equilibrium state. The emergence through the photosphere of such a kinked tube would create an active region which was tilted with respect to Hale's law and which would rotate as it evolved, as δ-spots are observed to do. We then find that, when excited by multiple unstable kink modes, highly twisted flux tubes develop concentrated kinks. These concentrated kinks would produce more of the observed characteristics of δ-spot active regions. They would create active regions which, in addition to emerging tilted and then rotating, would remain compact as they evolved, and develop strong shear along their magnetic neutral line. Finally, we find that a strong concentrated kink develops a current sheet at which the magnetic field reconnects, which may be the cause of the high flare activity of δ-spots.

  2. A Metabolic Biofuel Cell: Conversion of Human Leukocyte Metabolic Activity to Electrical Currents

    PubMed Central

    2011-01-01

    An investigation of the electrochemical activity of human white blood cells (WBC) for biofuel cell (BFC) applications is described. WBCs isolated from whole human blood were suspended in PBS and introduced into the anode compartment of a proton exchange membrane (PEM) fuel cell. The cathode compartment contained a 50 mM potassium ferricyanide solution. Average current densities between 0.9 and 1.6 μA cm-2 and open circuit potentials (Voc) between 83 and 102 mV were obtained, which were both higher than control values. Cyclic voltammetry was used to investigate the electrochemical activity of the activated WBCs in an attempt to elucidate the mechanism of electron transfer between the cells and electrode. Voltammograms were obtained for the WBCs, including peripheral blood mononuclear cells (PBMCs - a lymphocyte-monocyte mixture isolated on a Ficoll gradient), a B lymphoblastoid cell line (BLCL), and two leukemia cell lines, namely K562 and Jurkat. An oxidation peak at about 363 mV vs. SCE for the PMA (phorbol ester) activated primary cells, with a notable absence of a reduction peak was observed. Oxidation peaks were not observed for the BLCL, K562 or Jurkat cell lines. HPLC confirmed the release of serotonin (5-HT) from the PMA activated primary cells. It is believed that serotonin, among other biochemical species released by the activated cells, contributes to the observed BFC currents. PMID:21569243

  3. Association between physical activity and major depressive disorder among current or former smokers with pulmonary disease.

    PubMed

    Loprinzi, Paul D; Kane, Christy; Walker, Jerome F

    2013-11-01

    To examine the association between physical activity and major depressive disorder (MDD) in a nationally representative sample of current or former smokers with pulmonary impairments. The analyzed sample from the National Health and Nutrition Examination Survey (NHANES) 2007-2010 included 536 adults who indicated that they were current or former smokers, had at least mild pulmonary impairment (FEV1/FVC<0.70), and provided depression and physical activity data. After controlling for asthma status, pulmonary impairment, age, poverty-to-income ratio (PIR), education, gender, marital status, body mass index (BMI), cotinine, comorbidity index, race-ethnicity, and smoking status, those who met physical activity guidelines had a 59% (odds ratio (OR)=0.41; 95% confidence interval (CI): 0.18-0.94) lower odds of having MDD. Using multivariate linear regression with depression symptoms as the outcome variable, and after adjustments, physical activity was inversely associated with depression symptoms in a dose-response manner; lowest tertile was the referent group, middle tertile coefficient: -1.06 (95% CI: -1.98 to -0.14), and highest tertile coefficient: -1.10 (95% CI: -1.84 to -0.34). Physical activity inversely associates with MDD in adults with pulmonary impairments, and does so in a dose-response manner. This suggests that individuals with pulmonary impairments should be encouraged to engage in enjoyable, safe forms of physical activity in a progressive manner. © 2013.

  4. Low-order design and high-order simulation of active closed-loop control for aerospace structures under construction

    NASA Technical Reports Server (NTRS)

    Balas, Mark J.

    1989-01-01

    Partially constructed/assembled structures in space are complicated enough but their dynamics will also be operating in closed-loop with feedback controllers. The dynamics of such structures are modeled by large-scale finite element models. The model dimension L is extremely large (approximately 10,000) while the numbers of actuators (M) and sensors (P) are small. The model parameters M(sub m) mass matrix, D(sub o) damping matrix, and K(sub o) stiffness matrix, are all symmetric and sparse (banded). Thus simulation of open-loop structure models of very large dimension can be accomplished by special integration techniques for sparse matrices. The problem of simulation of closed-loop control of such structures is complicated by the addition of controllers. Simulation of closed-loop controlled structures is an essential part of the controller design and evaluation process. Current research in the following areas is presented: high-order simulation of actively controlled aerospace structures; low-order controller design and SCI compensation for unmodeled dynamics; prediction of closed-loop stability using asymptotic eigenvalue series; and flexible robot manipulator control experiment.

  5. The morphology of flare phenomena, magnetic fields, and electric currents in active regions. II - NOAA active region 5747 (1989 October)

    NASA Technical Reports Server (NTRS)

    Leka, K. D.; Canfield, Richard C.; Mcclymont, A. N.; De La Beaujardiere, J.-F.; Fan, Yuhong; Tang, F.

    1993-01-01

    The paper describes October 1989 observations in NOAA Active Region 5747 of the morphology of energetic electron precipitation and high-pressure coronal flare plasmas of three flares and their relation to the vector magnetic field and vertical electric currents. The H-alpha spectroheliograms were coaligned with the vector magnetograms using continuum images of sunspots, enabling positional accuracy of a few arcsec. It was found that, during the gradual phase, the regions of the H-alpha flare that show the effects of enhanced pressure in the overlying corona often encompass extrema of the vertical current density, consistent with earlier work showing a close relationship between H-alpha emission and line-of-sight currents. The data are also consistent with the overall morphology and evolution described by erupting-filament models such as those of Kopp and Pneuman (1976) and Sturrock (1989).

  6. Hyperpolarization-Activated Current, I f, in Mathematical Models of Rabbit Sinoatrial Node Pacemaker Cells

    PubMed Central

    Verkerk, Arie O.

    2013-01-01

    A typical feature of sinoatrial (SA) node pacemaker cells is the presence of an ionic current that activates upon hyperpolarization. The role of this hyperpolarization-activated current, I f, which is also known as the “funny current” or “pacemaker current,” in the spontaneous pacemaker activity of SA nodal cells remains a matter of intense debate. Whereas some conclude that I f plays a fundamental role in the generation of pacemaker activity and its rate control, others conclude that the role of I f is limited to a modest contribution to rate control. The ongoing debate is often accompanied with arguments from computer simulations, either to support one's personal view or to invalidate that of the antagonist. In the present paper, we review the various mathematical descriptions of I f that have been used in computer simulations and compare their strikingly different characteristics with our experimental data. We identify caveats and propose a novel model for I f based on our experimental data. PMID:23936852

  7. Calcium-activated chloride current amplifies the response to urine in mouse vomeronasal sensory neurons

    PubMed Central

    Yang, Chun

    2010-01-01

    The vomeronasal organ (VNO) is an odor detection system that mediates many pheromone-sensitive behaviors. Vomeronasal sensory neurons (VSNs), located in the VNO, are the initial site of interaction with odors/pheromones. However, how an individual VSN transduces chemical signals into electrical signals is still unresolved. Here, we show that a Ca2+-activated Cl− current contributes ∼80% of the response to urine in mouse VSNs. Using perforated patch clamp recordings with gramicidin, which leaves intracellular chloride undisrupted, we found that the urine-induced inward current (Vhold = −80 mV) was decreased in the presence of chloride channel blockers. This was confirmed using whole cell recordings and altering extracellular chloride to shift the reversal potential. Further, the urine-induced currents were eliminated when both extracellular Ca2+ and Na+ were removed. Using inside-out patches from dendritic tips, we recorded Ca2+-activated Cl− channel activity. Several candidates for this Ca2+-activated Cl− channel were detected in VNO by reverse transcription–polymerase chain reaction. In addition, a chloride cotransporter, Na+-K+-2Cl− isoform 1, was detected and found to mediate much of the chloride accumulation in VSNs. Collectively, our data demonstrate that chloride acts as a major amplifier for signal transduction in mouse VSNs. This amplification would increase the responsiveness to pheromones or odorants. PMID:20038523

  8. A self-sensing active magnetic bearing based on a direct current measurement approach.

    PubMed

    Niemann, Andries C; van Schoor, George; du Rand, Carel P

    2013-09-11

    Active magnetic bearings (AMBs) have become a key technology in various industrial applications. Self-sensing AMBs provide an integrated sensorless solution for position estimation, consolidating the sensing and actuating functions into a single electromagnetic transducer. The approach aims to reduce possible hardware failure points, production costs, and system complexity. Despite these advantages, self-sensing methods must address various technical challenges to maximize the performance thereof. This paper presents the direct current measurement (DCM) approach for self-sensing AMBs, denoting the direct measurement of the current ripple component. In AMB systems, switching power amplifiers (PAs) modulate the rotor position information onto the current waveform. Demodulation self-sensing techniques then use bandpass and lowpass filters to estimate the rotor position from the voltage and current signals. However, the additional phase-shift introduced by these filters results in lower stability margins. The DCM approach utilizes a novel PA switching method that directly measures the current ripple to obtain duty-cycle invariant position estimates. Demodulation filters are largely excluded to minimize additional phase-shift in the position estimates. Basic functionality and performance of the proposed self-sensing approach are demonstrated via a transient simulation model as well as a high current (10 A) experimental system. A digital implementation of amplitude modulation self-sensing serves as a comparative estimator.

  9. A Self-Sensing Active Magnetic Bearing Based on a Direct Current Measurement Approach

    PubMed Central

    Niemann, Andries C.; van Schoor, George; du Rand, Carel P.

    2013-01-01

    Active magnetic bearings (AMBs) have become a key technology in various industrial applications. Self-sensing AMBs provide an integrated sensorless solution for position estimation, consolidating the sensing and actuating functions into a single electromagnetic transducer. The approach aims to reduce possible hardware failure points, production costs, and system complexity. Despite these advantages, self-sensing methods must address various technical challenges to maximize the performance thereof. This paper presents the direct current measurement (DCM) approach for self-sensing AMBs, denoting the direct measurement of the current ripple component. In AMB systems, switching power amplifiers (PAs) modulate the rotor position information onto the current waveform. Demodulation self-sensing techniques then use bandpass and lowpass filters to estimate the rotor position from the voltage and current signals. However, the additional phase-shift introduced by these filters results in lower stability margins. The DCM approach utilizes a novel PA switching method that directly measures the current ripple to obtain duty-cycle invariant position estimates. Demodulation filters are largely excluded to minimize additional phase-shift in the position estimates. Basic functionality and performance of the proposed self-sensing approach are demonstrated via a transient simulation model as well as a high current (10 A) experimental system. A digital implementation of amplitude modulation self-sensing serves as a comparative estimator. PMID:24030681

  10. Volunteering and overseas placements in the NHS: a survey of current activity

    PubMed Central

    Chatwin, John; Ackers, Louise

    2016-01-01

    Objective The study aimed to establish current levels of overseas volunteering and placement activity across all staff grades within the National Health Service (NHS) in the North West of England. Design Cross-sectional survey. Instrument Descriptive statistics. Setting 4 main regional hospitals in the North West of England, and additional NHS staff training events. Participants Convenience sample of NHS staff (n=911). Results 911 NHS staff took part in the survey. The medical and dental staff group returned the highest number of responses (32.1%). 42% of staff reported some form of overseas volunteering or placement experience. Most staff took an international placement as students (33.6% men; 40.6% women). Medium-term placements were undertaken by 46.7% of men, and 52.5% of women. Settlement stays (ie, over 1 year) were reported by 7.6% men, and 8.3% women). The majority of respondents engaged in international placement were from the age groups incorporating ‘below 25’ to ‘41–50’ (74%). Multiple placement experiences were uncommon: 2.5% of respondents reported three periods of overseas activity, and 1.5% reported four. All those with multiple placement experience came from the staff groups incorporating midwife/nurse/health visitor, and medical and dental. Conclusions This survey captured a snapshot of current levels of volunteering and overseas placement activity across NHS staff grades in the North West. Owing to relatively homogenous organisational structures, findings are likely to broadly represent the position across the organisation as a whole. Although some degree of overseas placement activity is undertaken by a relatively high proportion of NHS staff, such activity is currently heavily skewed towards higher clinical staff grades. Significant numbers of allied health professionals and equivalent non-clinical cadres also report overseas experience, and we anticipate that the numbers will continue to rise if current policy initiatives gain

  11. Current limitations and recommendations to improve testing for the environmental assessment of endocrine active substances.

    PubMed

    Coady, Katherine K; Biever, Ronald C; Denslow, Nancy D; Gross, Melanie; Guiney, Patrick D; Holbech, Henrik; Karouna-Renier, Natalie K; Katsiadaki, Ioanna; Krueger, Hank; Levine, Steven L; Maack, Gerd; Williams, Mike; Wolf, Jeffrey C; Ankley, Gerald T

    2017-03-01

    In the present study, existing regulatory frameworks and test systems for assessing potential endocrine active chemicals are described, and associated challenges are discussed, along with proposed approaches to address these challenges. Regulatory frameworks vary somewhat across geographies, but all basically evaluate whether a chemical possesses endocrine activity and whether this activity can result in adverse outcomes either to humans or to the environment. Current test systems include in silico, in vitro, and in vivo techniques focused on detecting potential endocrine activity, and in vivo tests that collect apical data to detect possible adverse effects. These test systems are currently designed to robustly assess endocrine activity and/or adverse effects in the estrogen, androgen, and thyroid hormone signaling pathways; however, there are some limitations of current test systems for evaluating endocrine hazard and risk. These limitations include a lack of certainty regarding: 1) adequately sensitive species and life stages; 2) mechanistic endpoints that are diagnostic for endocrine pathways of concern; and 3) the linkage between mechanistic responses and apical, adverse outcomes. Furthermore, some existing test methods are resource intensive with regard to time, cost, and use of animals. However, based on recent experiences, there are opportunities to improve approaches to and guidance for existing test methods and to reduce uncertainty. For example, in vitro high-throughput screening could be used to prioritize chemicals for testing and provide insights as to the most appropriate assays for characterizing hazard and risk. Other recommendations include adding endpoints for elucidating connections between mechanistic effects and adverse outcomes, identifying potentially sensitive taxa for which test methods currently do not exist, and addressing key endocrine pathways of possible concern in addition to those associated with estrogen, androgen, and thyroid

  12. TMEM16A channels generate Ca2+-activated Cl− currents in cerebral artery smooth muscle cells

    PubMed Central

    Thomas-Gatewood, Candice; Neeb, Zachary P.; Bulley, Simon; Adebiyi, Adebowale; Bannister, John P.; Leo, M. Dennis

    2011-01-01

    Transmembrane protein (TMEM)16A channels are recently discovered membrane proteins that display electrophysiological properties similar to classic Ca2+-activated Cl− (ClCa) channels in native cells. The molecular identity of proteins that generate ClCa currents in smooth muscle cells (SMCs) of resistance-size arteries is unclear. Similarly, whether cerebral artery SMCs generate ClCa currents is controversial. Here, using molecular biology and patch-clamp electrophysiology, we examined TMEM16A channel expression and characterized Cl− currents in arterial SMCs of resistance-size rat cerebral arteries. RT-PCR amplified transcripts for TMEM16A but not TMEM16B–TMEM16H, TMEM16J, or TMEM16K family members in isolated pure cerebral artery SMCs. Western blot analysis using an antibody that recognized recombinant (r)TMEM16A channels detected TMEM16A protein in cerebral artery lysates. Arterial surface biotinylation and immunofluorescence indicated that TMEM16A channels are located primarily within the arterial SMC plasma membrane. Whole cell ClCa currents in arterial SMCs displayed properties similar to those generated by rTMEM16A channels, including Ca2+ dependence, current-voltage relationship linearization by an elevation in intracellular Ca2+ concentration, a Nerstian shift in reversal potential induced by reducing the extracellular Cl− concentration, and a negative reversal potential shift when substituting extracellular I− for Cl−. A pore-targeting TMEM16A antibody similarly inhibited both arterial SMC ClCa and rTMEM16A currents. TMEM16A knockdown using small interfering RNA also inhibited arterial SMC ClCa currents. In summary, these data indicate that TMEM16A channels are expressed, insert into the plasma membrane, and generate ClCa currents in cerebral artery SMCs. PMID:21856902

  13. Microbial community response during the treatment of pharmaceutically active compounds (PhACs) in constructed wetland mesocosms.

    PubMed

    Yan, Qing; Min, Jie; Yu, Yonghong; Zhu, Zhiwei; Feng, Guozhong

    2017-11-01

    The presence of pharmaceutically active compounds (PhACs) in wastewater treatment plant effluent poses a potential risk to aquatic ecosystems. Constructed wetlands have recently been used to control PhACs. However, the microbial communities that are involved in these processes have not been comprehensively investigated. This study aimed to evaluate the removal of PhACs and microbial response in constructed wetlands during the treatment of PhACs. The effects of PhACs on bacterial communities in constructed wetland mesocosms were analyzed by Illumina MiSeq sequencing technology. Results indicated that removal efficiencies of PhACs were enhanced over time, and constructed wetlands offer higher removal efficiencies for the PhACs studied compared to conventional wastewater treatment plants. Plants improved microbial richness and diversity while both indices were negatively correlated with PhAC concentrations ranging from 30 to 500 μg/L in constructed wetland mesocosms. The microbial communities of the constructed wetland mesocosms were dominated by Proteobacteria, Acidobacteria, and Bacteroidetes under PhAC exposure, while Desulfobulbus and Treponema were the dominant genera. In particular, Proteobacteria were correlated with PhAC concentrations. Overall, this study provides valuable microbial community ecology data to understand how microbial populations respond to PhAC stress in constructed wetlands. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. [Construction of pORF-mIG and activity evaluation of MIG in vitro].

    PubMed

    Zhang, Ru; Tian, Ling; Xiao, Fei; Wen, Yan-jun; li, Jiong; Hou, Jian-mei; Zhang, Ling; Li, Gang; Yao, Bing; Chen, Xian-cheng; Mel, Kai

    2006-07-01

    To establish a transformant of monokine induced by interferon-gamma (MIG) with the eukaryotic expression vector for further investigating the efficacy of its use in antitumor gene therapy. The MIG full-length cDNA was amplified from pBLAST-MIG and was cloned into the eukaryote expression vector pORF-mcs, and the resulted recombinant plasmid was named pORF-MIG. The recombinant pORF-MIG was determined with restriction enzyme and sequencing, and then it was transfected into COS-7 cells by Lipfectamin. Expression of the transformant was detected by immunoblot assay, and the bioactivity was assessed by chemotaxis assay. The restriction analysis and the sequence determination confirmed that the recombinant pORF-MIG contained the MIG full-length cDNA. And the transformants of pORF-MIG expressed the MIG protein which could apparently attract the activated lymphocytes. The recombinant pORF-MIG was constructed successfully, and this recombinant eukaryotic expression vector could be used in additional studies on the biological effect of MIG and its use in anti-tumor gene therapy.

  15. Highly active carbonaceous nanofibers: a versatile scaffold for constructing multifunctional free-standing membranes.

    PubMed

    Liang, Hai-Wei; Zhang, Wen-Jun; Ma, Yi-Ni; Cao, Xiang; Guan, Qing-Fang; Xu, Wei-Ping; Yu, Shu-Hong

    2011-10-25

    Translating the unique characteristics of individual nanoscale components into macroscopic materials such as membranes or sheets still remains a challenge, as the engineering of these structures often compromises their intrinsic properties. Here, we demonstrate that the highly active carbonaceous nanofibers (CNFs), which are prepared through a template-directed hydrothermal carbonization process, can be used as a versatile nanoscale scaffold for constructing macroscopic multifunctional membranes. In order to demonstrate the broad applicability of the CNF scaffold, we fabricate a variety of CNF-based composite nanofibers, including CNFs-Fe(3)O(4), CNFs-TiO(2), CNFs-Ag, and CNFs-Au through various chemical routes. Importantly, all of them inherit unique dimensionality (high aspect ratio) and mechanical properties (flexibility) of the original CNF scaffolds and thus can be assembled into macroscopic free-standing membranes through a simple casting process. We also demonstrate the wide application potentials of these multifunctional composite membranes in magnetic actuation, antibiofouling filtration, and continuous-flow catalysis.

  16. Construction of Escherichia coli Mutant with Decreased Endotoxic Activity by Modifying Lipid A Structure

    PubMed Central

    Liu, Qiong; Li, Yanyan; Zhao, Xinxin; Yang, Xue; Liu, Qing; Kong, Qingke

    2015-01-01

    Escherichia coli BL21 (DE3) and its derivatives are widely used for the production of recombinant proteins, but these purified proteins are always contaminated with lipopolysaccharide (LPS). LPS is recognized by the toll-like receptor 4 and myeloid differentiation factor 2 complex of mammalian immune cells and leads to release of pro-inflammatory cytokines. It is a vital step to remove LPS from the proteins before use for therapeutic purpose. In this study, we constructed BL21 (DE3) ∆msbB28 ∆pagP38 mutant, which produces a penta-acylated LPS with reduced endotoxicity. The plasmids harboring pagL and/or lpxE were then introduced into this mutant to further modify the LPS. The new strain (S004) carrying plasmid pQK004 (pagL and lpxE) produced mono-phosphoryated tetra-acylated lipid A, which induces markedly less production of tumor necrosis factor-α in the RAW264.7 and IL-12 in the THP1, but still retains ability to produce recombinant proteins. This study provides a strategy to decrease endotoxic activity of recombinant proteins purified from E. coli BL21 backgrounds and a feasible approach to modify lipid A structure for alternative purposes such as mono-phosphoryl lipid A (MPL) as vaccine adjuvants. PMID:26023843

  17. Properties of a calcium-activated K(+) current on interneurons in the developing rat hippocampus.

    PubMed

    Aoki, T; Baraban, S C

    2000-06-01

    Calcium-activated potassium currents have an essential role in regulating excitability in a variety of neurons. Although it is well established that mature CA1 pyramidal neurons possess a Ca(2+)-activated K(+) conductance (I(K(Ca))) with early and late components, modulation by various endogenous neurotransmitters, and sensitivity to K(+) channel toxins, the properties of I(K(Ca)) on hippocampal interneurons (or immature CA1 pyramidal neurons) are relatively unknown. To address this problem, whole-cell voltage-clamp recordings were made from visually identified interneurons in stratum lacunosum-moleculare (L-M) and CA1 pyramidal cells in hippocampal slices from immature rats (P3-P25). A biphasic calcium-activated K(+) tail current was elicited following a brief depolarization from the holding potential (-50 mV). Analysis of the kinetic properties of I(K(Ca)) suggests that an early current component differs between these two cell types. An early I(K(Ca)) with a large peak current amplitude (200.8 +/- 13.2 pA, mean +/- SE), slow time constant of decay (70.9 +/- 3.3 ms), and relatively rapid time to peak (within 15 ms) was observed on L-M interneurons (n = 88), whereas an early I(K(Ca)) with a small peak current amplitude (112.5 +/- 7.3 pA), a fast time constant of decay (39.4 +/- 1.6 ms), and a slower time-to-peak (within 26 ms) was observed on CA1 pyramidal neurons (n = 85). Removal of extracellular calcium or addition of inorganic Ca(2+) channel blockers (cadmium, nickel, or cobalt) was used to demonstrate the calcium dependence of these currents. Addition of norepinephrine, carbachol, and a variety of channel toxins (apamin, iberiotoxin, verruculogen, paxilline, penitrem A, and charybdotoxin) were used to further distinguish between I(K(Ca)) on these two hippocampal cell types. Verruculogen (100 nM), carbachol (100 microM), apamin (100 nM), TEA (1 mM), and iberiotoxin (50 nM) significantly reduced early I(K(Ca)) on CA1 pyramidal neurons; early I(K(Ca)) on L

  18. Voltage-dependent activation of potassium current in Helix neurones by endogenous cellular calcium.

    PubMed Central

    Akaike, N; Brown, A M; Dahl, G; Higashi, H; Isenberg, G; Tsuda, Y; Yatani, A

    1983-01-01

    1. The effect of endogenous Ca on potential-dependent K current IKD, was examined in identifiable neurones of Helix aspersa. The suction pipette method of internal perfusion was used along with a combined voltage-clamp method in which the membrane potential was measured by a separate glass micro-electrode and the current was passed by the suction pipette. Activation of the potential-dependent A current, IA, was prevented by using holding potentials of -40 mV where IA is inactivated and by the addition of the A-current blocker 4-aminopyridine. Activation of K currents by transmembrane Ca current, IKCa, was suppressed by Co substitution for Ca ion extracellularly. 2. Under these conditions, IKD rose to a peak value and then subsided to a steady level. The current-voltage (I-V) relationship for peak IKD had an upward bump at about +50 mV that gave it an S-shape. The I-V curve for steady IKD rose continuously. Peak and steady IKD were reduced by perfusing with EGTA or F ions intracellularly. The EGTA effect occurred at intracellular Ca activity levels below 10(-7) M. Increases in the concentration of EGTAi at constant Cai had no additional effect; however, recovery experiments do not allow us to rule out some direct action of EGTA on IKD. 3. Prolonged extracellular perfusion with Co-substituted solutions also reduced IKD and the effects occurred more quickly when the solutions were made hypertonic or caffeine was added to them. The peak transient was abolished, and the small remaining steady IKD (about 5-10% of normal peak IKD) was blocked by tetraethylammonium. IKD could be restored by the temporary reintroduction of Ca in the extracellular solution. 4. The S-shape of the peak I-V relationship for IKD may be due to Ca released from an endogenous site by membrane depolarization. The reduction of steady and peak IKD to very low values by Ca chelators or prolonged perfusion with Ca-free solutions indicates that Cai is important for activation of these K channels. 5

  19. Quantum-classical transition and quantum activation of ratchet currents in the parameter space.

    PubMed

    Beims, M W; Schlesinger, M; Manchein, C; Celestino, A; Pernice, A; Strunz, W T

    2015-05-01

    The quantum ratchet current is studied in the parameter space of the dissipative kicked rotor model coupled to a zero-temperature quantum environment. We show that vacuum fluctuations blur the generic isoperiodic stable structures found in the classical case. Such structures tend to survive when a measure of statistical dependence between the quantum and classical currents are displayed in the parameter space. In addition, we show that quantum fluctuations can be used to overcome transport barriers in the phase space. Related quantum ratchet current activation regions are spotted in the parameter space. Results are discussed based on quantum, semiclassical, and classical calculations. While the semiclassical dynamics involves vacuum fluctuations, the classical map is driven by thermal noise.

  20. Biomarkers of endothelial activation and thrombosis in tunnel construction workers exposed to airborne contaminants.

    PubMed

    Ellingsen, Dag G; Seljeflot, Ingebjørg; Thomassen, Yngvar; Thomassen, Magny; Bakke, Berit; Ulvestad, Bente

    2017-05-01

    The aims were to study biomarkers of systemic inflammation, platelet/endothelial activation and thrombosis in tunnel construction workers (TCW). Biomarkers and blood fatty acids were measured in blood of 90 TCW and 50 referents before (baseline) and towards the end (follow-up) of a 12 days work period. They had been absent from work for 9 days at baseline. Air samples were collected by personal sampling. Personal thoracic air samples showed geometric mean (GM) particulate matter and α-quartz concentrations of 604 and 74 µg/m(3), respectively. The arithmetic mean (AM) concentration of elemental carbon was 51 µg/m(3). The GM (and 95% confidence interval) concentration of the pro-inflammatory cytokine TNF-α decreased from 2.2 (2.0-2.4) at baseline to 2.0 pg/mL (1.8-2.2) (p = 0.02) at follow-up among the TCW. Also the platelet activation biomarkers P-selectin and CD40L decreased significantly [25.4 (24.1-26.6) to 24.4 (22.9-26.0)] ng/mL, p = 0.04 and 125 (114-137) to 105 (96-115) pg/mL, p < 0.001, respectively. ICAM-1 concentrations increased from 249 (238-260) to 254 (243-266) ng/mL (p = 0.02). No significant alterations were observed among the referents when assessed by paired sample t test. Unbeneficial alterations in blood fatty acid composition were observed between baseline and follow-up, mainly among referents. TCW had slightly reduced systemic inflammation and platelet activation although highly exposed to particulate matter, α-quarz and diesel exhaust, which might be due to increased physical activity during the exposure period. The slightly increased ICAM-1 may indicate monocyte recruitment to the lungs. The diet was substantially altered towards a less beneficial fatty acid profile.

  1. Modulation of membrane currents and mechanical activity by niflumic acid in rat vascular smooth muscle.

    PubMed

    Kirkup, A J; Edwards, G; Green, M E; Miller, M; Walker, S D; Weston, A H

    1996-12-12

    The effects of niflumic acid on whole-cell membrane currents and mechanical activity were examined in the rat portal vein. In freshly dispersed portal vein cells clamped at -60 mV in caesium (Cs+)-containing solutions, niflumic acid (1-100 microM) inhibited calcium (Ca2+)-activated chloride currents (IC1(Ca)) induced by caffeine (10 mM) and by noradrenaline (10 microM). In a potassium (K+)-containing solution and at a holding potential of - 10 mV, niflumic acid (10-100 microM) induced an outward K+ current (IK(ATP)) which was sensitive to glibenclamide (10-30 microM). At concentrations < 30 microM and at a holding potential of -2 mV, niflumic acid had no effect on the magnitude of the caffeine- or noradrenaline-stimulated current (IBK(Ca)) carried by the large conductance, Ca(2+)-sensitive K+ channel (BKCa). However, at a concentration of 100 microM, niflumic acid significantly inhibited IBK(Ca)) evoked by caffeine (10 mM) but not by NS1619 (1-(2'-hydroxy-5'-trifluoromethylphenyl)-5-trifluoromethyl-2(3 H) benzimidazolone; 20 microM). In Cs(+)-containing solutions, niflumic acid (10-100 microM) did not inhibit voltage-sensitive Ca2+ currents. In intact portal veins, niflumic acid (1-300 microM) inhibited spontaneous mechanical activity, an action which was partially antagonised by glibenclamide (1-10 microM), and contractions produced by noradrenaline (10 microM), an effect which was glibenclamide-insensitive. It is concluded that inhibition of ICl(Ca) and stimulation of IK(ATP) both contribute to the mechano-inhibitory actions of niflumic acid in the rat portal vein.

  2. Active to sterile neutrino mixing limits from neutral-current interactions in MINOS.

    PubMed

    Adamson, P; Auty, D J; Ayres, D S; Backhouse, C; Barr, G; Bishai, M; Blake, A; Bock, G J; Boehnlein, D J; Bogert, D; Cavanaugh, S; Cherdack, D; Childress, S; Coelho, J A B; Coleman, S J; Corwin, L; Cronin-Hennessy, D; Danko, I Z; de Jong, J K; Devenish, N E; Diwan, M V; Dorman, M; Escobar, C O; Evans, J J; Falk, E; Feldman, G J; Frohne, M V; Gallagher, H R; Gomes, R A; Goodman, M C; Gouffon, P; Graf, N; Gran, R; Grant, N; Grzelak, K; Habig, A; Harris, D; Hartnell, J; Hatcher, R; Himmel, A; Holin, A; Huang, X; Hylen, J; Ilic, J; Irwin, G M; Isvan, Z; Jaffe, D E; James, C; Jensen, D; Kafka, T; Kasahara, S M S; Koizumi, G; Kopp, S; Kordosky, M; Kreymer, A; Lang, K; Lefeuvre, G; Ling, J; Litchfield, P J; Loiacono, L; Lucas, P; Mann, W A; Marshak, M L; Mayer, N; McGowan, A M; Mehdiyev, R; Meier, J R; Messier, M D; Miller, W H; Mishra, S R; Mitchell, J; Moore, C D; Morfín, J; Mualem, L; Mufson, S; Musser, J; Naples, D; Nelson, J K; Newman, H B; Nichol, R J; Nicholls, T C; Nowak, J A; Oliver, W P; Orchanian, M; Paley, J; Patterson, R B; Pawloski, G; Pearce, G F; Petyt, D A; Phan-Budd, S; Pittam, R; Plunkett, R K; Qiu, X; Ratchford, J; Raufer, T M; Rebel, B; Rodrigues, P A; Rosenfeld, C; Rubin, H A; Sanchez, M C; Schneps, J; Schreiner, P; Sharma, R; Shanahan, P; Sousa, A; Stamoulis, P; Strait, M; Tagg, N; Talaga, R L; Tetteh-Lartey, E; Thomas, J; Thomson, M A; Tinti, G; Toner, R; Torretta, D; Tzanakos, G; Urheim, J; Vahle, P; Viren, B; Walding, J J; Weber, A; Webb, R C; White, C; Whitehead, L; Wojcicki, S G; Zwaska, R

    2011-07-01

    Results are reported from a search for active to sterile neutrino oscillations in the MINOS long-baseline experiment, based on the observation of neutral-current neutrino interactions, from an exposure to the NuMI neutrino beam of 7.07×10(20) protons on target. A total of 802 neutral-current event candidates is observed in the Far Detector, compared to an expected number of 754 ± 28(stat) ± 37(syst) for oscillations among three active flavors. The fraction f(s) of disappearing ν(μ) that may transition to ν(s) is found to be less than 22% at the 90% C.L.

  3. Active to Sterile Neutrino Mixing Limits from Neutral-Current Interactions in MINOS

    SciTech Connect

    Adamson, P.; Bock, G. J.; Boehnlein, D. J.; Bogert, D.; Childress, S.; Harris, D.; Hatcher, R.; Hylen, J.; James, C.; Jensen, D.; Koizumi, G.; Kreymer, A.; Lucas, P.; Moore, C. D.; Morfin, J.; Plunkett, R. K.; Rebel, B.; Sharma, R.; Shanahan, P.; Torretta, D.

    2011-07-01

    Results are reported from a search for active to sterile neutrino oscillations in the MINOS long-baseline experiment, based on the observation of neutral-current neutrino interactions, from an exposure to the NuMI neutrino beam of 7.07x10{sup 20} protons on target. A total of 802 neutral-current event candidates is observed in the Far Detector, compared to an expected number of 754{+-}28(stat){+-}37(syst) for oscillations among three active flavors. The fraction f{sub s} of disappearing {nu}{sub {mu}} that may transition to {nu}{sub s} is found to be less than 22% at the 90% C.L.

  4. Activation of protein kinase C inhibits potassium currents in cultured endothelial cells.

    PubMed

    Zhang, H; Weir, B; Daniel, E E

    1995-04-01

    The effect of protein kinase C on potassium channels in cultured endothelial cells was investigated by using whole-cell patch-clamp techniques. Activation of protein kinase C by phorbol 12-myristate 13-acetate (PMA) and phorbol 12,13-dibutyrate (PDBu), but not phorbol 12-monomyristate (PMM), an inactive analogue of phorbol esters, depressed an outward calcium-dependent potassium current. The inhibitory actions of PMA and PDBu could be reversed by the kinase inhibitor H-7. Cyclopiazonic acid, an inhibitor of the sarcoplasmic reticulum calcium pump, and LP-805, a novel vasodilator which also releases endothelium-derived relaxing factors, activated the outward calcium-dependent potassium conductance. PMA and PDBu, but not PMM, reduced the outward conductance induced by cyclopiazonic acid and LP-805. These effects of PMA and PDBu on potassium currents may be mediated either by phosphorylation of ion channels, or by decreasing intracellular calcium concentration.

  5. Alpha-2 noradrenergic receptor activation inhibits the hyperpolarization-activated cation current (Ih ) in neurons of the ventral tegmental area

    PubMed Central

    Inyushin, Mikhail U.; Arencibia-Albite, Francisco; Vázquez-Torres, Rafael; Vélez-Hernández, María E.; Jiménez-Rivera, Carlos A.

    2010-01-01

    The ventral tegmental area (VTA) is the source of dopaminergic projections innervating cortical structures and ventral forebrain. Dysfunction of this mesocorticolimbic system is critically involved in psychiatric disorders such as addiction and schizophrenia. Changes in VTA dopamine (DA) neuronal activity can alter neurotransmitter release at target regions which modify information processing in the reward circuit. Here we studied the effect of α-2 noradrenergic receptor activation on the hyperpolarization-activated cation current (Ih ) in DA neurons of the rat VTA. Brain slice preparations using whole-cell current and voltage-clamp techniques were employed. Clonidine and UK14304 (α-2 receptor selective agonists) were found to decrease Ih amplitude and to slow its rate of activation indicating a negative shift in the current’s voltage dependence. Two non-subtype-selective α-2 receptor antagonists, yohimbine and RS79948, prevented the effects of α-2 receptor activation. RX821002, a noradrenergic antagonist specific for α-2A and α-2D did not prevent Ih inhibition. This result suggests that clonidine might be acting via an α-2C subtype since this receptor is the most abundant variant in the VTA. Analysis of a second messenger system associated with the α-2 receptor revealed that Ih inhibition is independent of cyclic adenosine monophosphate (cAMP) and resulted from the activation of protein kinase C. It is suggested that the α-2 mediated hyperpolarizing shift in Ih voltage dependence can facilitate the transition from pacemaker firing to afferent-driven burst activity. This transition may play a key role on the changes in synaptic plasticity that occurs in the mesocorticolimbic system under pathological conditions. PMID:20122999

  6. Phorbol ester activation of chloride current in guinea-pig ventricular myocytes.

    PubMed Central

    Shuba, L. M.; Asai, T.; McDonald, T. F.

    1996-01-01

    1. Although earlier studies with phorbol esters indicate that protein kinase C (PKC) may be an important regulator of Cl- current (Icl) in cardiac cells, there is a need for additional quantitative data and investigation of conflicting findings. Our objectives were to measure the magnitude, time course, and concentration-dependence of Icl activated in guinea-pig ventricular myocytes by phorbol 12-myristate 13-acetate (PMA), evaluate its PKC dependence, and examine its modification by external and internal ions. 2. The whole-cell patch clamp technique was used to apply short depolarizing and hyperpolarizing pulses to myocytes superfused with Na(+)-, K(+)-, Ca(2+)-free solution (36 degrees C) and dialysed with Cs+ solution. Stimulation of membrane currents by PMA (threshold < or = 1nM, EC50 approximately equal to 14 nM, maximal 40% increase with > or = 100 nM) plateaued within 6-10 min. 3. PMA-activated current was time-independent, and suppressed by l mM 9-anthracenecarboxylic acid (9-AC). Its reversal potential (Erev) was sensitive to changes in the Cl- gradient, and outward rectification of the current-voltage (I-V) relationship was more pronounced with 30 mM than 140 mM Cl- dialysate. 4. The relative permeability of PMA-activated channels estimated from Erev measurements was I- > Cl- > > aspartate. Channel activation was independent of external Na+. 5. PMA failed to activate Icl in myocytes pretreated with 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) or dialysed with pCa 10.5 solution. Lack of response to 4 alpha-phorbol 12, 13-didecanoate (alpha PDD) was a further indication of mediation by PKC. 6. Icl induced by 2 microM forskolin was far larger than that induced by PMA, suggesting that endogenous protein kinase A is a much stronger Cl- channel activator than endogenous PKC in these myocytes. 7. The macroscopic properties of PMA-induced Icl appear to be indistinguishable from those of PKA-activated Icl. We discount stimulation of PKA by PMA as an

  7. Sensitivity optimization of active filters containing current conveyors and controlled sources

    NASA Astrophysics Data System (ADS)

    Dunning-Davies, J.; Stephenson, F. W.

    1980-03-01

    Employing a technique associated with optimization problems, a minimum sensitivity solution is obtained for a third-order active filter containing a current conveyor. This solution is given in terms of the time constants for the circuit. Further investigation yields a solution in terms of the resistors and capacitors which, as well as being one of minimum sensitivity, is such that the resistor sum and spread and capacitor sum and spread are all small. Similar results are presented for a third-order active filter containing a controlled source.

  8. Effect of Direct-Current Electric Field on Enzymatic Activity and the Concentration of Laccase.

    PubMed

    Wang, Chunxing; Zhang, Huiling; Ren, Dajun; Li, Qian; Zhang, Shuqin; Feng, Tao

    2015-09-01

    This work investigates the effect of direct-current electric field on the extracellular enzymatic activity, concentration and other experimental parameters of laccase from Trametes versicolor. The results showed that laccase could significantly contribute to the change of pH at the end of graphite electrode. In addition, it increased the electrical conductivity of the water. In the experiment, the optimum pH and catalytic pH range for laccase activity were 3.0 and pH 2.5-4.0. The application of 6 V direct current showed significant effects on the laccase enzyme activity. The activity of laccase was enhanced in the anodic region, but at the same time was strongly inhibited at the cathode. The electric charge characteristics of laccase were changed when exposed to electric field, and some laccases molecules moved to the anode, which produced a slight migration phenomenon. This study is the basis of combination of laccase and electrical technology, at the same time, providing a new direction of enhancing laccase activity. Compared to immobilization, using electric field is simple, no chemical additives, and great potential.

  9. Control of spontaneous firing patterns by the selective coupling of calcium currents to calcium-activated potassium currents in striatal cholinergic interneurons.

    PubMed

    Goldberg, Joshua A; Wilson, Charles J

    2005-11-02

    The spontaneous firing patterns of striatal cholinergic interneurons are sculpted by potassium currents that give rise to prominent afterhyperpolarizations (AHPs). Large-conductance calcium-activated potassium (BK) channel currents contribute to action potential (AP) repolarization; small-conductance calcium-activated potassium channel currents generate an apamin-sensitive medium AHP (mAHP) after each AP; and bursts of APs generate long-lasting slow AHPs (sAHPs) attributable to apamin-insensitive currents. Because all these currents are calcium dependent, we conducted voltage- and current-clamp whole-cell recordings while pharmacologically manipulating calcium channels of the plasma membrane and intracellular stores to determine what sources of calcium activate the currents underlying AP repolarization and the AHPs. The Cav2.2 (N-type) blocker omega-conotoxin GVIA (1 microM) was the only blocker that significantly reduced the mAHP, and it induced a transition to rhythmic bursting in one-third of the cells tested. Cav1 (L-type) blockers (10 microM dihydropyridines) were the only ones that significantly reduced the sAHP. When applied to cells induced to burst with apamin, dihydropyridines reduced the sAHPs and abolished bursting. Depletion of intracellular stores with 10 mM caffeine also significantly reduced the sAHP current and reversibly regularized firing. Application of 1 microM omega-conotoxin MVIIC (a Cav2.1/2.2 blocker) broadened APs but had a negligible effect on APs in cells in which BK channels were already blocked by submillimolar tetraethylammonium chloride, indicating that Cav2.1 (Q-type) channels provide the calcium to activate BK channels that repolarize the AP. Thus, calcium currents are selectively coupled to the calcium-dependent potassium currents underlying the AHPs, thereby creating mechanisms for control of the spontaneous firing patterns of these neurons.

  10. A Mathematical Model of Neonatal Rat Atrial Monolayers with Constitutively Active Acetylcholine-Mediated K+ Current

    PubMed Central

    Majumder, Rupamanjari; Jangsangthong, Wanchana; Feola, Iolanda; Ypey, Dirk L.; Pijnappels, Daniël A.; Panfilov, Alexander V.

    2016-01-01

    Atrial fibrillation (AF) is the most frequent form of arrhythmia occurring in the industrialized world. Because of its complex nature, each identified form of AF requires specialized treatment. Thus, an in-depth understanding of the bases of these arrhythmias is essential for therapeutic development. A variety of experimental studies aimed at understanding the mechanisms of AF are performed using primary cultures of neonatal rat atrial cardiomyocytes (NRAMs). Previously, we have shown that the distinct advantage of NRAM cultures is that they allow standardized, systematic, robust re-entry induction in the presence of a constitutively-active acetylcholine-mediated K+ current (IKACh-c). Experimental studies dedicated to mechanistic explorations of AF, using these cultures, often use computer models for detailed electrophysiological investigations. However, currently, no mathematical model for NRAMs is available. Therefore, in the present study we propose the first model for the action potential (AP) of a NRAM with constitutively-active acetylcholine-mediated K+ current (IKACh-c). The descriptions of the ionic currents were based on patch-clamp data obtained from neonatal rats. Our monolayer model closely mimics the action potential duration (APD) restitution and conduction velocity (CV) restitution curves presented in our previous in vitro studies. In addition, the model reproduces the experimentally observed dynamics of spiral wave rotation, in the absence and in the presence of drug interventions, and in the presence of localized myofibroblast heterogeneities. PMID:27332890

  11. An Improved Harmonic Current Detection Method Based on Parallel Active Power Filter

    NASA Astrophysics Data System (ADS)

    Zeng, Zhiwu; Xie, Yunxiang; Wang, Yingpin; Guan, Yuanpeng; Li, Lanfang; Zhang, Xiaoyu

    2017-05-01

    Harmonic detection technology plays an important role in the applications of active power filter. The accuracy and real-time performance of harmonic detection are the precondition to ensure the compensation performance of Active Power Filter (APF). This paper proposed an improved instantaneous reactive power harmonic current detection algorithm. The algorithm uses an improved ip -iq algorithm which is combined with the moving average value filter. The proposed ip -iq algorithm can remove the αβ and dq coordinate transformation, decreasing the cost of calculation, simplifying the extraction process of fundamental components of load currents, and improving the detection speed. The traditional low-pass filter is replaced by the moving average filter, detecting the harmonic currents more precisely and quickly. Compared with the traditional algorithm, the THD (Total Harmonic Distortion) of the grid currents is reduced from 4.41% to 3.89% for the simulations and from 8.50% to 4.37% for the experiments after the improvement. The results show the proposed algorithm is more accurate and efficient.

  12. Polarographic study of hydrogen peroxide anodic current and its application to antioxidant activity determination.

    PubMed

    Sužnjević, Desanka Ž; Pastor, Ferenc T; Gorjanović, Stanislava Ž

    2011-09-15

    Behavior of hydrogen peroxide in alkaline medium has been studied by direct current (DC) polarography with dropping mercury electrode (DME) aiming to apply it in antioxidant (AO) activity determination. Development of a peroxide anodic current having form of a peak, instead of common polarographic wave, has been investigated. As a base for this investigation the interaction of H(2)O(2) with anodically dissolved mercury was followed. Formation of mercury complex [Hg(O(2)H)(OH)] has been confirmed. The relevant experimental conditions, such as temperature, concentration and pH dependence, as well as time stability of hydrogen peroxide anodic current, have been assessed. Development of an AO assay based on decrease of anodic current of hydrogen peroxide in the presence of antioxidants (AOs) has been described. Under optimized working conditions, a series of benzoic acids along with corresponding cinnamate analogues have been tested for hydrogen peroxide scavenging activity. In addition, the assay versatility has been confirmed on various complex samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. C-kinase activation prolongs Ca2+-dependent inactivation of K+ currents.

    PubMed

    Alkon, D L; Kubota, M; Neary, J T; Naito, S; Coulter, D; Rasmussen, H

    1986-02-13

    Voltage-dependent K+ currents, IA and ICa2+-K+, across the soma membrane of the Hermissenda Type B photoreceptor, have been shown to remain reduced during retention of classically conditioned behavior. IA and ICa2+-K+ undergo prolonged reduction due to [Ca2+]i elevation produced by a single pairing of a light step with a command depolarization or by iontophoretic injection of Ca2+. One pathway which could contribute to the conversion of transient Ca2+-mediated reduction of K+ currents to the persistent reduction observed with conditioning is that involving C-kinase. To examine the role of C-kinase in the long-term regulation of K+ currents, isolated Type B somata were exposed to at least 25-30 minutes' incubation in artificial sea water (ASW) containing the C-kinase activators 1-oleoyl-2-acetyl-glycerol (OAG) or 12-deoxyphorbol 13-isobutyrate 20-acetate (DPBA) or control substances [e.g., distearyolglycerol (DiSG)]. After exposure to activator (but not to control solutions) and voltage-clamp conditions which caused elevation of cytosolic Ca2+, reductions of IA and ICa2+-K+ were observed which did not reverse (up to 3 hr), even after the activator was removed. Without conditions which induced elevation of cytosolic calcium prolonged incubation with the C-kinase activators had no effect on the membrane currents. Similar exposure of homogenates of the Hermissenda nervous system to OAG and Ca2+ caused enhanced phosphorylation of specific proteins, indicating the presence of C-kinase in the Hermissenda nervous system.

  14. Current California legislative and regulatory activity impacting geothermal hydrothermal commercialization: a monitoring report. Report No. 1017

    SciTech Connect

    Not Available

    1980-01-20

    Four key geothermal-impacting bills presently before the California legislature are described. Two deal with state financial backing for geothermal projects. The third relates to the use of the state's share of the BLM geothermal revenues and the fourth to the protection of sensitive hot springs. The current regulatory activities of the California Energy Commission, the California Division of Oil and Gas, and the counties are discussed. (MHR)

  15. Central European MetEor NeTwork: Current status and future activities

    NASA Astrophysics Data System (ADS)

    Srba, J.; Koukal, J.; Ferus, M.; Lenža, L.; Gorková, S.; Civiš, S.; Simon, J.; Csorgei, T.; Jedlièka, M.; Korec, M.; Kaniansky, S.; Polák, J.; Spurný, M.; Brázdil, T.; Mäsiar, J.; Zima, M.; Delinèák, P.; Popek, M.; Bahýl, V.; Piffl, R.; Èechmánek, M.

    2016-06-01

    The Central European video Meteor Network (CEMeNt) established in 2010 is a platform for cross-border cooperation in the field of video meteor observations between Czech Republic and Slovakia. During five years of operation the CEMeNt network went through an extensive development. In total, 37 video systems were working on 20 permanent stations located in Czech Republic and Slovakia during 2015. In this paper we summarize CEMeNt current status and introduce some future activities.

  16. Nicotine inhibits activation of microglial proton currents via interactions with α7 acetylcholine receptors.

    PubMed

    Noda, Mami; Kobayashi, A I

    2017-01-01

    Alpha 7 subunits of nicotinic acetylcholine receptors (nAChRs) are expressed in microglia and are involved in the suppression of neuroinflammation. Over the past decade, many reports show beneficial effects of nicotine, though little is known about the mechanism. Here we show that nicotine inhibits lipopolysaccharide (LPS)-induced proton (H(+)) currents and morphological change by using primary cultured microglia. The H(+) channel currents were measured by whole-cell patch clamp method under voltage-clamp condition. Increased H(+) current in activated microglia was attenuated by blocking NADPH oxidase. The inhibitory effect of nicotine was due to the activation of α7 nAChR, not a direct action on the H(+) channels, because the effects of nicotine was cancelled by α7 nAChR antagonists. Neurotoxic effect of LPS-activated microglia due to inflammatory cytokines was also attenuated by pre-treatment of microglia with nicotine. These results suggest that α7 nAChRs in microglia may be a therapeutic target in neuroinflammatory diseases.

  17. Apelin-13 Enhances Arcuate POMC Neuron Activity via Inhibiting M-Current

    PubMed Central

    Lee, Dong Kun; Jeong, Jae Hoon; Oh, Seunghoon; Jo, Young-Hwan

    2015-01-01

    The hypothalamus is a key element of the neural circuits that control energy homeostasis. Specific neuronal populations within the hypothalamus are sensitive to a variety of homeostatic indicators such as circulating nutrient levels and hormones that signal circulating glucose and body fat content. Central injection of apelin secreted by adipose tissues regulates feeding and glucose homeostasis. However, the precise neuronal populations and cellular mechanisms involved in these physiological processes remain unclear. Here we examine the electrophysiological impact of apelin-13 on proopiomelanocortin (POMC) neuron activity. Approximately half of POMC neurons examined respond to apelin-13. Apelin-13 causes a dose-dependent depolarization. This effect is abolished by the apelin (APJ) receptor antagonist. POMC neurons from animals pre-treated with pertussis toxin still respond to apelin, whereas the Gβγ signaling inhibitor gallein blocks apelin-mediated depolarization. In addition, the effect of apelin is inhibited by the phospholipase C and protein kinase inhibitors. Furthermore, single-cell qPCR analysis shows that POMC neurons express the APJ receptor, PLC-β isoforms, and KCNQ subunits (2, 3 and 5) which contribute to M-type current. Apelin-13 inhibits M-current that is blocked by the KCNQ channel inhibitor. Therefore, our present data indicate that apelin activates APJ receptors, and the resultant dissociation of the Gαq heterotrimer triggers a Gβγ-dependent activation of PLC-β signaling that inhibits M-current. PMID:25782002

  18. Sedentary behaviour and physical activity in South Asian women: time to review current recommendations?

    PubMed

    Waidyatilaka, Indu; Lanerolle, Pulani; Wickremasinghe, Rajitha; Atukorala, Sunethra; Somasundaram, Noel; de Silva, Angela

    2013-01-01

    Our aims were to describe activity and sedentary behaviours in urban Asian women, with dysglycaemia (diagnosed at recruitment), and without dysglycaemia and examine the relative contribution of these parameters to their glycaemic status. 2800 urban women (30-45 years) were selected by random cluster sampling and screened for dysglycaemia for a final sample of 272 newly diagnosed, drug naive dysglycaemic and 345 normoglycaemic women. Physical activity and sedentary behaviours were assessed by the International Physical Activity Questionnaire (IPAQ). Demographic data, diet and anthropometry were recorded. Logistic regression analysis assessed contribution of all parameters to dysglycaemia and exposure attributable fractions were calculated. The mean energy expenditure on walking (2648.5±1023.7 MET-min/week) and on moderate and vigorous physical activity (4342.3±1768.1 MET-min/week) for normoglycemic women and dysglycaemic women (walking;1046.4±728.4 MET-min/week, moderate and vigorous physical activity; 1086.7±1184.4 MET-min/week) was above the recommended amount of physical activity per week. 94.3% of women spent >1000 MET-minutes/week on activity. Mean sitting and TV time for normoglycaemic and dysglycaemic women were 154.3±62.8, 38.4±31.9, 312.6±116.7 and 140.2±56.5 minutes per day respectively. Physical activity and sedentary behaviour contributed to dysglycaemia after adjustment for family history, diet, systolic blood pressure and Body Mass Index. Exposure attributable fractions for dysglycaemia were; lower physical activity: 78%, higher waist circumference: 94%, and TV viewing time: 85%. Urban South Asian women are at risk of dysglycaemia at lower levels of sedentary behaviour and greater physical activity than western populations, indicating the need for re-visiting current physical activity guidelines for South Asians.

  19. 34 CFR 222.173 - What activities will not receive funding under a Discretionary Construction grant?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Discretionary Construction grant? 222.173 Section 222.173 Education Regulations of the Offices of the Department of Education OFFICE OF ELEMENTARY AND SECONDARY EDUCATION, DEPARTMENT OF EDUCATION IMPACT AID PROGRAMS Impact Aid Discretionary Construction Grant Program Under Section 8007(b) of the Act General §...

  20. Building a Tree Structure: The Development of Hierarchical Complexity and Interrupted Strategies in Children's Construction Activity

    ERIC Educational Resources Information Center

    Greenfield, Patricia Marks; Schneider, Leslie

    1977-01-01

    This study examined the construction of a mobile with plastic construction straws in order to study the development of tree representations in a domain other than language. Subjects were 70 children between the ages of 3 and 11. (Author/JMB)