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Sample records for membrane olm revisited

  1. The outer limiting membrane (OLM revisited: clinical implications

    Directory of Open Access Journals (Sweden)

    S Omri

    2010-03-01

    Full Text Available S Omri1,2,3, B Omri1,2,3, M Savoldelli1,2,3,4, L Jonet1,2,3, B Thillaye-Goldenberg1,2,3, G Thuret5, P Gain5, J C Jeanny1,2,3, P Crisanti1,2,3, Francine Behar-Cohen1,2,3,41INSERM, U872 Physiopathology of ocular diseases: Therapeutic innovations, Paris, France; 2Centre de Recherche des Cordeliers, Université Pierre et Marie Curie – Paris6, Paris, France; 3Université Paris Descartes, Paris, France; 4Department of Ophthalmology, Hôtel-Dieu de Paris, France; 5Department of Ophthalmology, Bellevue Hospital, University of Saint-Etienne, FrancePurpose: The outer limiting membrane (OLM is considered to play a role in maintaining the structure of the retina through mechanical strength. However, the observation of junction proteins located at the OLM and its barrier permeability properties may suggest that the OLM may be part of the retinal barrier.Material and methods: Normal and diabetic rat, monkey, and human retinas were used to analyze junction proteins at the OLM. Proteome analyses were performed using immunohistochemistry on sections and flat-mounted retinas and western blotting on protein extracts obtained from laser microdissection of the photoreceptor layers. Semi-thin and ultrastructure analyses were also reported.Results: In the rat retina, in the subapical region zonula occludens-1 (ZO-1, junction adhesion molecule (JAM, an atypical protein kinase C, is present and the OLM shows dense labeling of occludin, JAM, and ZO-1. The presence of occludin has been confirmed using western blot analysis of the microdissected OLM region. In diabetic rats, occludin expression is decreased and glial cells junctions are dissociated. In the monkey retina, occludin, JAM, and ZO-1 are also found in the OLM. Junction proteins have a specific distribution around cone photoreceptors and Müller glia. Ultrastructural analyses suggest that structures like tight junctions may exist between retinal glial Müller cells and photoreceptors.Conclusions: In the OLM

  2. Spherical indentation of a freestanding circular membrane revisited: Analytical solutions and experiments

    Science.gov (United States)

    Jin, Congrui; Davoodabadi, Ali; Li, Jianlin; Wang, Yanli; Singler, Timothy

    2017-03-01

    Due to the development of novel micro-fabrication techniques to produce ultra-thin materials and increasing interest in thin biological membranes, in recent years, the mechanical characterization of thin films has received a significant amount of attention. To provide a more accurate solution for the relationship among contact radius, load and deflection, the fundamental and widely applicable problem of spherical indentation of a freestanding circular membrane have been revisited. The work presented here significantly extends the previous contributions by providing an exact analytical solution to the governing equations of Föppl-Hecky membrane indented by a frictionless spherical indenter. In this study, experiments of spherical indentation has been performed, and the exact analytical solution presented in this paper is compared against experimental data from existing literature as well as our own experimental results.

  3. Revisited

    DEFF Research Database (Denmark)

    Tegtmeier, Silke; Meyer, Verena; Pakura, Stefanie

    2017-01-01

    were captured when they described entrepreneurs. Therefore, this paper aims to revisit gender role stereotypes among young adults. Design/methodology/approach: To measure stereotyping, participants were asked to describe entrepreneurs in general and either women or men in general. The Schein......: The images of men and entrepreneurs show a high and significant congruence (r = 0.803), mostly in those adjectives that are untypical for men and entrepreneurs. The congruence of women and entrepreneurs was low (r = 0.152) and insignificant. Contrary to the participants’ beliefs, their explicit notions did...... not have any effect on measures of congruence. However, young adults who knew business owners in their surroundings rated the congruence of women and entrepreneurs significantly higher (r = 0.272) than average. Originality/value: This study is unique in combining “implicit” stereotypes and explicit notions...

  4. Re-visiting the tympanic membrane vicinity as core body temperature measurement site.

    Directory of Open Access Journals (Sweden)

    Wui Keat Yeoh

    Full Text Available Core body temperature (CBT is an important and commonly used indicator of human health and endurance performance. A rise in baseline CBT can be attributed to an onset of flu, infection or even thermoregulatory failure when it becomes excessive. Sites which have been used for measurement of CBT include the pulmonary artery, the esophagus, the rectum and the tympanic membrane. Among them, the tympanic membrane is an attractive measurement site for CBT due to its unobtrusive nature and ease of measurement facilitated, especially when continuous CBT measurements are needed for monitoring such as during military, occupational and sporting settings. However, to-date, there are still polarizing views on the suitability of tympanic membrane as a CBT site. This paper will revisit a number of key unresolved issues in the literature and also presents, for the first time, a benchmark of the middle ear temperature against temperature measurements from other sites. Results from experiments carried out on human and primate subjects will be presented to draw a fresh set of insights against the backdrop of hypotheses and controversies.

  5. Re-visiting the tympanic membrane vicinity as core body temperature measurement site

    Science.gov (United States)

    Gan, Chee Wee; Liang, Wenyu

    2017-01-01

    Core body temperature (CBT) is an important and commonly used indicator of human health and endurance performance. A rise in baseline CBT can be attributed to an onset of flu, infection or even thermoregulatory failure when it becomes excessive. Sites which have been used for measurement of CBT include the pulmonary artery, the esophagus, the rectum and the tympanic membrane. Among them, the tympanic membrane is an attractive measurement site for CBT due to its unobtrusive nature and ease of measurement facilitated, especially when continuous CBT measurements are needed for monitoring such as during military, occupational and sporting settings. However, to-date, there are still polarizing views on the suitability of tympanic membrane as a CBT site. This paper will revisit a number of key unresolved issues in the literature and also presents, for the first time, a benchmark of the middle ear temperature against temperature measurements from other sites. Results from experiments carried out on human and primate subjects will be presented to draw a fresh set of insights against the backdrop of hypotheses and controversies. PMID:28414722

  6. From Interactive Open Learner Modelling to Intelligent Mentoring: STyLE-OLM and Beyond

    Science.gov (United States)

    Dimitrova, Vania; Brna, Paul

    2016-01-01

    STyLE-OLM (Dimitrova 2003 "International Journal of Artificial Intelligence in Education," 13, 35-78) presented a framework for interactive open learner modelling which entails the development of the means by which learners can "inspect," "discuss" and "alter" the learner model that has been jointly…

  7. Monitoring health and reproductive status of olms (Proteus anguinus by ultrasound.

    Directory of Open Access Journals (Sweden)

    Susanne Holtze

    Full Text Available The olm (Proteus anguinus is a troglomorphic, neotenous amphibian with extraordinary life expectancy and unique adaptations that deserve further investigation. A low reproductive rate and habitat decline render it threatened by extinction. Establishing captive populations for maintenance and artificial breeding may one day become crucial to the species. Longitudinal, in-vivo assessment of inner organs is invaluable to our understanding of reproductive physiology, health, and behavior. Using ultrasound, we measured heart rate and assessed health and reproductive status of 13 captive olms at Zagreb Zoo. Heart rate averaged 42.9 ± 4.6 bpm (32-55 bpm, as determined via pulsed-wave Doppler at 4-12 MHz. By using frequencies of up to 70 MHz (ultrasound biomicroscopy, inner organs were visualized in detail. Assessment of the gastrointestinal tract provided insights into feeding status and digestive processes. Several subclinical pathologies were detected, including biliary sludge, subcutaneous edema, ascites, and skin lesions. Detection of skin lesions by ultrasound was more sensitive than visual adspection. Olms with ultrasonographically detected skin lesions tested positive for Saprolegnia and were treated. Three of the four affected individuals survived and subsequently tested negative for Saprolegnia. Sex was reliably determined; only one individual proved male. The reason for this extreme female-biased sex-ratio remains unknown. However, as most of the individuals were flushed from the caves by strong currents in spring, the sample may not be representative of natural populations. In female olms, different stages of ovarian follicular development were observed with diameters ranging between 0.1 and 1.1 mm. Results were confirmed by comparing ultrasound, necropsy, and histological findings of one dead specimen. In summary, ultrasound proved a valuable tool to support conservation and captive breeding programs by allowing non-invasive assessment of

  8. Monitoring health and reproductive status of olms (Proteus anguinus) by ultrasound.

    Science.gov (United States)

    Holtze, Susanne; Lukač, Maja; Cizelj, Ivan; Mutschmann, Frank; Szentiks, Claudia Anita; Jelić, Dušan; Hermes, Robert; Göritz, Frank; Braude, Stanton; Hildebrandt, Thomas Bernd

    2017-01-01

    The olm (Proteus anguinus) is a troglomorphic, neotenous amphibian with extraordinary life expectancy and unique adaptations that deserve further investigation. A low reproductive rate and habitat decline render it threatened by extinction. Establishing captive populations for maintenance and artificial breeding may one day become crucial to the species. Longitudinal, in-vivo assessment of inner organs is invaluable to our understanding of reproductive physiology, health, and behavior. Using ultrasound, we measured heart rate and assessed health and reproductive status of 13 captive olms at Zagreb Zoo. Heart rate averaged 42.9 ± 4.6 bpm (32-55 bpm), as determined via pulsed-wave Doppler at 4-12 MHz. By using frequencies of up to 70 MHz (ultrasound biomicroscopy), inner organs were visualized in detail. Assessment of the gastrointestinal tract provided insights into feeding status and digestive processes. Several subclinical pathologies were detected, including biliary sludge, subcutaneous edema, ascites, and skin lesions. Detection of skin lesions by ultrasound was more sensitive than visual adspection. Olms with ultrasonographically detected skin lesions tested positive for Saprolegnia and were treated. Three of the four affected individuals survived and subsequently tested negative for Saprolegnia. Sex was reliably determined; only one individual proved male. The reason for this extreme female-biased sex-ratio remains unknown. However, as most of the individuals were flushed from the caves by strong currents in spring, the sample may not be representative of natural populations. In female olms, different stages of ovarian follicular development were observed with diameters ranging between 0.1 and 1.1 mm. Results were confirmed by comparing ultrasound, necropsy, and histological findings of one dead specimen. In summary, ultrasound proved a valuable tool to support conservation and captive breeding programs by allowing non-invasive assessment of physiological

  9. Concentrations of anesthetics across the water-membrane interface; the Meyer-Overton hypothesis revisited

    Science.gov (United States)

    Pohorille, A.; Wilson, M. A.; New, M. H.; Chipot, C.

    1998-01-01

    The free energies of transferring a variety of anesthetic and nonanesthetic compounds across water-oil and water-membrane interfaces were obtained using computer simulations. Anesthetics exhibit greatly enhanced concentrations at these interfaces, compared to nonanesthetics. The substitution of the interfacial solubilites of the anesthetics for their bulk lipid solubilities in the Meyer-Overton relation, was found to give a better correlation, indicating that the potency of an anesthetic is directly proportional to its solubility at the interface.

  10. Evaluation of NO2 predictions by the plume volume molar ratio method (PVMRM) and ozone limiting method (OLM) in AERMOD using new field observations.

    Science.gov (United States)

    Hendrick, Elizabeth M; Tino, Vincent R; Hanna, Steven R; Egan, Bruce A

    2013-07-01

    The U.S. Environmental Protection Agency (EPA) plume volume molar ratio method (PVMRM) and the ozone limiting method (OLM) are in the AERMOD model to predict the 1-hr average NO2/NO(x) concentration ratio. These ratios are multiplied by the AERMOD predicted NO(x) concentration to predict the 1-hr average NO2 concentration. This paper first briefly reviews PVMRM and OLM and points out some scientific parameterizations that could be improved (such as specification of relative dispersion coefficients) and then discusses an evaluation of the PVMRM and OLM methods as implemented in AERMOD using a new data set. While AERMOD has undergone many model evaluation studies in its default mode, PVMRM and OLM are nondefault options, and to date only three NO2 field data sets have been used in their evaluations. Here AERMOD/PVMRM and AERMOD/OLM codes are evaluated with a new data set from a northern Alaskan village with a small power plant. Hourly pollutant concentrations (NO, NO2, ozone) as well as meteorological variables were measured at a single monitor 500 m from the plant. Power plant operating parameters and emissions were calculated based on hourly operator logs. Hourly observations covering 1 yr were considered, but the evaluations only used hours when the wind was in a 60 degrees sector including the monitor and when concentrations were above a threshold. PVMRM is found to have little bias in predictions of the C(NO2)/C(NO(x)) ratio, which mostly ranged from 0.2 to 0.4 at this site. OLM overpredicted the ratio. AERMOD overpredicts the maximum NO(x) concentration but has an underprediction bias for lower concentrations. AERMOD/PVMRM overpredicts the maximum C(NO2) by about 50%, while AERMOD/OLM overpredicts by a factor of 2. For 381 hours evaluated, there is a relative mean bias in C(NO2) predictions of near zero for AERMOD/PVMRM, while the relative mean bias reflects a factor of 2 overprediction for AERMOD/OLM. This study was initiated because the new stringent 1-hr NO2

  11. Dendritic distributions of Ih channels in experimentally-derived multi-compartment models of oriens-lacunosum/moleculare (O-LM hippocampal interneurons

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    Vladislav eSekulic

    2015-02-01

    Full Text Available The O-LM cell type mediates feedback inhibition onto hippocampal pyramidal cells and gates information flow in the CA1. Its functions depend on the presence of voltage-gated channels (VGCs, which affect its integrative properties and response to synaptic input. Given the challenges associated with determining densities and distributions of VGCs on interneuron dendrites, we take advantage of computational modeling to consider different possibilities. In this work, we focus on hyperpolarization-activated channels (h-channels in O-LM cells. While h-channels are known to be present in O-LM cells, it is unknown whether they are present on their dendrites. In previous work, we used ensemble modeling techniques with experimental data to obtain insights into potentially important conductance balances. We found that the best O-LM models that included uniformly distributed h-channels in the dendrites could not fully capture the sag response. This led us to examine activation kinetics and non-uniform distributions of h-channels in the present work. In tuning our models, we found that different kinetics and non-uniform distributions could better reproduce experimental O-LM cell responses. In contrast to CA1 pyramidal cells where higher conductance densities of h-channels occur in more distal dendrites, decreasing conductance densities of h-channels away from the soma were observed in O-LM models. Via an illustrative scenario, we showed that having dendritic h-channels clearly speeds up back-propagating action potentials in O-LM cells, unlike when h-channels are present only in the soma. Although the present results were morphology-dependent, our work shows that it should be possible to determine the distributions and characteristics of O-LM cells with recordings and morphologies from the same cell. We hypothesize that h-channels are distributed in O-LM cell dendrites and endow them with particular synaptic integration properties that shape information flow

  12. Revisiting the Aluminum Trimesate-based MOF (MIL-96): from Structure Determination to the Processing of Mixed Matrix Membranes for CO2 Capture.

    KAUST Repository

    Benzaqui, Marvin

    2017-11-08

    A microporous Al trimesate-based metal-organic framework (MOF), denoted MIL-96-(Al), was selected as a porous hybrid filler for the processing of mixed matrix membranes (MMMs) for CO2/N-2 postcombustion separation. First, the structural model of MIL-96-(Al) initially reported was revisited using a combination of synchrotron-based single-crystal X-ray diffraction, solid-state nuclear magnetic resonance spectroscopy, and density functional theory (DFT) calculations. In a second step, pure MIL-96-(Al) crystals differing by their size and aspect ratio, including anisotropic hexagonal platelets and nanoparticles of about 70 nm in diameter, were prepared. Then, a combination of in situ IR spectroscopy, single-gas, and CO2/N-2 coadsorption experiments, calorimetry, and molecular simulations revealed that MIL-96-(Al) nanoparticles show a relatively high CO2 affinity over N-2 owing to strong interactions between CO2 molecules and several adsorption sites such as Al3+ Lewis centers, coordinated water, and hydroxyl groups. Finally, the high compatibility between MIL-96-(Al) nanoparticles and the 6FDA-DAM polymer allowed the processing of homogeneous and defect-free MMMs with a high MOF loading (up to 25 wt %) that outperform pure polymer membranes for CO2/N-2 separation.

  13. SMILE Revisited

    OpenAIRE

    Appelquist, Joakim; Ekelin, Annelie; Jila, Florian; Hallqvist, Klas

    2003-01-01

    The mobile service "SMILE" supporting care of the elderly is evaluated from an economic as well as an work practice perspective. SMILE Revisited beskriver utvecklingen, införandet och avvecklingen av ett system för mobilt stöd för hemtjänsten. Systemet analyseras dels ur ett ekonomiskt perspektiv, dels ur ett arbetsvetenskapligt perspektiv.

  14. The determinants of the growth expectations of the early-stage entrepreneurs (TEA using the ordinal logistic model (OLM: the case of Turkey

    Directory of Open Access Journals (Sweden)

    Ahmet Özçam

    2010-01-01

    Full Text Available This study uses the Ordinal Logistic Model (OLM to analyze the determinants of the growth expectations of total early-stage entrepreneurship activity (TEA expressed in terms of new jobs to be created within their firms in four categories. Specifically, given the increasing importance of entrepreneurship in job creation, innovation and economic growth, we try to inquire into the question of why some of the new entrepreneurs and not the others expect a rapid development of their ventures. The data from the Global Entrepreneurship Monitor (GEM for the years 2006-2008 for Turkey were employed. Our findings indicate that the personal characteristics of the early-stage Turkish entrepreneurs such as gender, education and household income, in addition to their motivation and current size of their businesses are important factors in resolving the prevalence of high-expectation new firms. Moreover, some scenarios particular to some sub-groups or population cells of Turkish developing entrepreneurs which may create the bulk of high-expectation entrepreneurial pursuit were conducted using OLM. As far as the policy implications are concerned, the availability and access of capital funding to early-stage entrepreneurs and an education system more relevant to today’s competitive world might both contribute better to Turkish economy’s prosperity, and seems to be very important for policy considerations.

  15. Defects in the outer limiting membrane are associated with rosette development in the Nrl-/- retina.

    Directory of Open Access Journals (Sweden)

    Michael W Stuck

    Full Text Available The neural retinal leucine zipper (Nrl knockout mouse is a widely used model to study cone photoreceptor development, physiology, and molecular biology in the absence of rods. In the Nrl(-/- retina, rods are converted into functional cone-like cells. The Nrl(-/- retina is characterized by large undulations of the outer nuclear layer (ONL commonly known as rosettes. Here we explore the mechanism of rosette development in the Nrl(-/- retina. We report that rosettes first appear at postnatal day (P8, and that the structure of nascent rosettes is morphologically distinct from what is seen in the adult retina. The lumen of these nascent rosettes contains a population of aberrant cells protruding into the subretinal space that induce infolding of the ONL. Morphologically adult rosettes do not contain any cell bodies and are first detected at P15. The cells found in nascent rosettes are photoreceptors in origin but lack inner and outer segments. We show that the adherens junctions between photoreceptors and Müller glia which comprise the retinal outer limiting membrane (OLM are not uniformly formed in the Nrl(-/- retina and thus allow protrusion of a population of developing photoreceptors into the subretinal space where their maturation becomes delayed. These data suggest that the rosettes of the Nrl(-/- retina arise due to defects in the OLM and delayed maturation of a subset of photoreceptors, and that rods may play an important role in the proper formation of the OLM.

  16. Grief revisited.

    Science.gov (United States)

    Ng, B Y

    2005-06-01

    The article serves to examine the cultural influences on attitudes towards the deceased and bereaved, as well as on the practice of mourning, and to revisit normal and pathological variants of grief. Grief is a subjective state of psychological and physiological reaction to the loss of a loved one. Reaction to the loss is experienced internally in a uniform manner across cultures. However, mourning, the voluntary social expression of the loss, varies from culture to culture. Rituals provide a standardised mode of behaviour, which helps to relieve the sense of uncertainty or loss. There were reports of ghost sightings involving foreign tourists in the 6 worst-hit southern provinces in Thailand following the tsunami tragedy. This phenomenon of "mass hallucinations" is understandable from the cultural perspective. New models of grief have been developed to account for the individuality and diversity of grief and to encompass the social, behavioural and spiritual dimensions of loss as well as those of the psychological and physical. Clinically, the duration of grief reactions varies widely, depending on the nature of the loss and the connection to the deceased. In the case of the tsunami tragedy, with relatives missing, homes swept away and familiar neighbourhoods turned into wastelands, many victims are likely to have complicated grief. Traumatic grief, which includes a prominent component of separation distress characterised by yearning and searching and frequent "bittersweet" recollections of the deceased, has been associated with long-term dysfunction. Grief work utilising the traumatic grief treatment protocol appears to be a promising intervention.

  17. Classics revisited

    DEFF Research Database (Denmark)

    Carter, A M

    2018-01-01

    of membranes comprising chorion towards the attachment site in the uterine fundus and inverted yolk sac on the opposite face. He showed that monozygotic twinning did not occur in another armadillo, the peludo (Chaetophractus villosus). CONCLUSIONS: Fernández's work represented a major breakthrough...... in understanding how twinning occurred in armadillos. His work and that of others is of intrinsic interest to zoologists and has a direct bearing on the origin of monozygotic twins and birth defects in humans....

  18. From biological membranes to biomimetic model membranes

    Directory of Open Access Journals (Sweden)

    Eeman, M.

    2010-01-01

    Full Text Available Biological membranes play an essential role in the cellular protection as well as in the control and the transport of nutrients. Many mechanisms such as molecular recognition, enzymatic catalysis, cellular adhesion and membrane fusion take place into the biological membranes. In 1972, Singer et al. provided a membrane model, called fluid mosaic model, in which each leaflet of the bilayer is formed by a homogeneous environment of lipids in a fluid state including globular assembling of proteins and glycoproteins. Since its conception in 1972, many developments were brought to this model in terms of composition and molecular organization. The main development of the fluid mosaic model was made by Simons et al. (1997 and Brown et al. (1997 who suggested that membrane lipids are organized into lateral microdomains (or lipid rafts with a specific composition and a molecular dynamic that are different to the composition and the dynamic of the surrounding liquid crystalline phase. The discovery of a phase separation in the plane of the membrane has induced an explosion in the research efforts related to the biology of cell membranes but also in the development of new technologies for the study of these biological systems. Due to the high complexity of biological membranes and in order to investigate the biological processes that occur on the membrane surface or within the membrane lipid bilayer, a large number of studies are performed using biomimicking model membranes. This paper aims at revisiting the fundamental properties of biological membranes in terms of membrane composition, membrane dynamic and molecular organization, as well as at describing the most common biomimicking models that are frequently used for investigating biological processes such as membrane fusion, membrane trafficking, pore formation as well as membrane interactions at a molecular level.

  19. Energetics of primary and secondary electron transfer in Photosystem II membrane particles of spinach revisited on basis of recombination-fluorescence measurements.

    Science.gov (United States)

    Grabolle, Markus; Dau, Holger

    2005-06-30

    Photon absorption by one of the roughly 200 chlorophylls of the plant Photosystem II (PSII) results in formation of an equilibrated excited state (Chl200*) and is followed by chlorophyll oxidation (formation of P680+) coupled to reduction of a specific pheophytin (Phe), then electron transfer from Phe- to a firmly bound quinone (QA), and subsequently reduction of P680+ by a redox-active tyrosine residue denoted as Z. The involved free-energy differences (DeltaG) and redox potentials are of prime interest. Oxygen-evolving PSII membrane particles of spinach were studied at 5 degrees C. By analyzing the delayed and prompt Chl fluorescence, we determined the equilibrium constant and thus free-energy difference between Chl200* and the [Z+,QA-] radical pair to be -0.43+/-0.025 eV, at 10 mus after the photon absorption event for PSII in its S(3)-state. On basis of this value and previously published results, the free-energy difference between P680* and [P680+,QA-] is calculated to be -0.50+/-0.04 eV; the free-energy loss associated with electron transfer from Phe to QA is found to be 0.34+/-0.04 eV. The given uncertainty ranges do not represent a standard deviation or likely error, but an estimate of the maximal error. Assuming a QA-/QA redox potential of -0.08 V, the following redox-potential estimates are obtained: +1.25 V for P680/P680+; +1.21 V for Z/Z+ (at 10 mus); -0.42 V for Phe-/Phe; -0.58 V for P680*/P680+.

  20. NATO: Revisiting American Commitment

    Science.gov (United States)

    2013-03-01

    NATO: Revisiting American Commitment by Captain Thomas F Hurley II United States Navy United...STRATEGY RESEARCH PROJECT .33 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE NATO: Revisiting American Commitment 5a. CONTRACT NUMBER...the 21st century. The strategic benefit to the United States may no longer be worth the commitment to the alliance. The U.S. should reevaluate its

  1. Revisiting city connectivity

    NARCIS (Netherlands)

    Mans, U.

    2014-01-01

    This article introduces a new perspective on city connectivity in order to analyze non-hub cities and their position in the world economy. The author revisits the different approaches discussed in the Global Commodity Chains (GCC), Global Production Networks (GPN) and World City Network (WCN)

  2. Revisiting Okun's Relationship

    NARCIS (Netherlands)

    Dixon, R.; Lim, G.C.; van Ours, Jan

    2016-01-01

    Our paper revisits Okun's relationship between observed unemployment rates and output gaps. We include in the relationship the effect of labour market institutions as well as age and gender effects. Our empirical analysis is based on 20 OECD countries over the period 1985-2013. We find that the

  3. Revisiting the Okun relationship

    NARCIS (Netherlands)

    Dixon, R. (Robert); Lim, G.C.; J.C. van Ours (Jan)

    2017-01-01

    textabstractOur article revisits the Okun relationship between observed unemployment rates and output gaps. We include in the relationship the effect of labour market institutions as well as age and gender effects. Our empirical analysis is based on 20 OECD countries over the period 1985–2013. We

  4. Revisiting the Rhetorical Curriculum

    Science.gov (United States)

    Rutten, Kris; Soetaert, Ronald

    2012-01-01

    The aim of the special strand on "Revisiting the rhetorical curriculum" is to explore the educational potential of a new rhetorical perspective, specifically in relation to different traditions within educational and rhetorical studies. This implies that we do not only look at education "in" rhetoric, but that we position education also "as" a…

  5. Revisiting Professional Teacher Standards

    Science.gov (United States)

    Watson, Amanda

    2016-01-01

    The Australian Society for Music Education's (ASME) involvement in the development of professional standards for music educators was a significant and active research time in the history of the Society. As ASME celebrates its golden jubilee, it is appropriate to revisit that history and consider the future prospects of subject-specific standards.…

  6. The Faraday effect revisited

    DEFF Research Database (Denmark)

    Cornean, Horia; Nenciu, Gheorghe

    2009-01-01

    This paper is the second in a series revisiting the (effect of) Faraday rotation. We formulate and prove the thermodynamic limit for the transverse electric conductivity of Bloch electrons, as well as for the Verdet constant. The main mathematical tool is a regularized magnetic and geometric...

  7. A Hydrostatic Paradox Revisited

    Science.gov (United States)

    Ganci, Salvatore

    2012-01-01

    This paper revisits a well-known hydrostatic paradox, observed when turning upside down a glass partially filled with water and covered with a sheet of light material. The phenomenon is studied in its most general form by including the mass of the cover. A historical survey of this experiment shows that a common misunderstanding of the phenomenon…

  8. Life quality index revisited

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager

    2004-01-01

    The derivation of the life quality index (LQI) is revisited for a revision. This revision takes into account the unpaid but necessary work time needed to stay alive in clean and healthy conditions to be fit for effective wealth producing work and to enjoyable free time. Dimension analysis consist...

  9. Seven Issues Revisited

    DEFF Research Database (Denmark)

    Grønbæk, Kaj; Whitehead, Jim; De Bra, Paul

    2002-01-01

    and Tailorability Since that time, these issues have formed the nucleus of multiple research agendas within the Hypertext community. Befitting this direction-setting role, the issues have been revisited several times, by Halasz in his 1991 Hypertext keynote talk, and by Randy Trigg in his 1996 Hypertext keynote...

  10. Remembered Experiences and Revisit Intentions

    DEFF Research Database (Denmark)

    Barnes, Stuart; Mattsson, Jan; Sørensen, Flemming

    2016-01-01

    path modelling, we examine the impact of positive affect tourist experiences on the development of revisit intentions. We find that longer-term remembered experiences have the strongest impact on revisit intentions, more so than predicted or immediate memory after an event. We also find that remembered...

  11. Deterministic Graphical Games Revisited

    DEFF Research Database (Denmark)

    Andersson, Daniel; Hansen, Kristoffer Arnsfelt; Miltersen, Peter Bro

    2008-01-01

    We revisit the deterministic graphical games of Washburn. A deterministic graphical game can be described as a simple stochastic game (a notion due to Anne Condon), except that we allow arbitrary real payoffs but disallow moves of chance. We study the complexity of solving deterministic graphical...... games and obtain an almost-linear time comparison-based algorithm for computing an equilibrium of such a game. The existence of a linear time comparison-based algorithm remains an open problem....

  12. Time functions revisited

    Science.gov (United States)

    Fathi, Albert

    2015-07-01

    In this paper we revisit our joint work with Antonio Siconolfi on time functions. We will give a brief introduction to the subject. We will then show how to construct a Lipschitz time function in a simplified setting. We will end with a new result showing that the Aubry set is not an artifact of our proof of existence of time functions for stably causal manifolds.

  13. Seven Issues, Revisited

    OpenAIRE

    Whitehead, Jim; De Bra, Paul; Grønbæk, Kaj; Larsen, Deena; Legget, John; schraefel, monica m.c.

    2002-01-01

    It has been 15 years since the original presentation by Frank Halasz at Hypertext'87 on seven issues for the next generation of hypertext systems. These issues are: Search and Query Composites Virtual Structures Computation in/over hypertext network Versioning Collaborative Work Extensibility and Tailorability Since that time, these issues have formed the nucleus of multiple research agendas within the Hypertext community. Befitting this direction-setting role, the issues have been revisited ...

  14. Reframing in dentistry: revisited.

    Science.gov (United States)

    Nuvvula, Sivakumar; Kamatham, Rekalakshmi; Challa, Ramasubbareddy; Asokan, Sharath

    2013-01-01

    The successful practice of dentistry involves a good combination of technical skills and soft skills. Soft skills or communication skills are not taught extensively in dental schools and it can be challenging to learn and at times in treating dental patients. Guiding the child's behavior in the dental operatory is one of the preliminary steps to be taken by the pediatric dentist and one who can successfully modify the behavior can definitely pave the way for a life time comprehensive oral care. This article is an attempt to revisit a simple behavior guidance technique, reframing and explain the possible psychological perspectives behind it for better use in the clinical practice.

  15. Reframing in dentistry: Revisited

    Directory of Open Access Journals (Sweden)

    Sivakumar Nuvvula

    2013-01-01

    Full Text Available The successful practice of dentistry involves a good combination of technical skills and soft skills. Soft skills or communication skills are not taught extensively in dental schools and it can be challenging to learn and at times in treating dental patients. Guiding the child′s behavior in the dental operatory is one of the preliminary steps to be taken by the pediatric dentist and one who can successfully modify the behavior can definitely pave the way for a life time comprehensive oral care. This article is an attempt to revisit a simple behavior guidance technique, reframing and explain the possible psychological perspectives behind it for better use in the clinical practice.

  16. Deterministic Graphical Games Revisited

    DEFF Research Database (Denmark)

    Andersson, Klas Olof Daniel; Hansen, Kristoffer Arnsfelt; Miltersen, Peter Bro

    2012-01-01

    Starting from Zermelo’s classical formal treatment of chess, we trace through history the analysis of two-player win/lose/draw games with perfect information and potentially infinite play. Such chess-like games have appeared in many different research communities, and methods for solving them......, such as retrograde analysis, have been rediscovered independently. We then revisit Washburn’s deterministic graphical games (DGGs), a natural generalization of chess-like games to arbitrary zero-sum payoffs. We study the complexity of solving DGGs and obtain an almost-linear time comparison-based algorithm...... for finding optimal strategies in such games. The existence of a linear time comparison-based algorithm remains an open problem....

  17. Metamorphosis in Craniiformea revisited

    DEFF Research Database (Denmark)

    Altenburger, Andreas; Wanninger, Andreas; Holmer, Lars E.

    2013-01-01

    We revisited the brachiopod fold hypothesis and investigated metamorphosis in the craniiform brachiopod Novocrania anomala. Larval development is lecithotrophic and the dorsal (brachial) valve is secreted by dorsal epithelia. We found that the juvenile ventral valve, which consists only of a thin....... We show that the “brachiopod fold hypothesis,” which argues that brachiopods are transversely “folded” across the ontogenetic anterior–posterior axis, should be rejected at least with respect to the craniiforms. The data now suggest that the Craniiformea may be a derived group within......), such as a through-gut and missing hinge articulation, may thus be secondarily derived characters of the Craniiformea within the Rhynchonelliformea....

  18. Revisiting The Depleted Self.

    Science.gov (United States)

    Abraham, Reggie

    2018-04-01

    This article revisits Donald Capps's book The Depleted Self (The depleted self: sin in a narcissistic age. Fortress Press, Minneapolis, 1993), which grew out of his 1990 Schaff Lectures at Pittsburgh Theological Seminary. In these lectures Capps proposed that the theology of guilt had dominated much of post-Reformation discourse. But with the growing prevalence of the narcissistic personality in the late twentieth century, the theology of guilt no longer adequately expressed humanity's sense of "wrongness" before God. Late twentieth-century persons sense this disjunction between God and self through shame dynamics. Narcissists are not "full" of themselves, as popular perspectives might indicate. Instead, they are empty, depleted selves. Psychologists suggest this stems from lack of emotional stimulation and the absence of mirroring in the early stages of life. The narcissist's search for attention and affirmation takes craving, paranoid, manipulative, or phallic forms and is essentially a desperate attempt to fill the internal emptiness. Capps suggests that two narratives from the Gospels are helpful here: the story of the woman with the alabaster jar and the story of Jesus's dialogue with Mary and John at Calvary. These stories provide us with clues as to how depleted selves experienced mirroring and the potential for internal peace in community with Jesus.

  19. Magnetic moments revisited

    International Nuclear Information System (INIS)

    Towner, I.S.; Khanna, F.C.

    1984-01-01

    Consideration of core polarization, isobar currents and meson-exchange processes gives a satisfactory understanding of the ground-state magnetic moments in closed-shell-plus (or minus)-one nuclei, A = 3, 15, 17, 39 and 41. Ever since the earliest days of the nuclear shell model the understanding of magnetic moments of nuclear states of supposedly simple configurations, such as doubly closed LS shells +-1 nucleon, has been a challenge for theorists. The experimental moments, which in most cases are known with extraordinary precision, show a small yet significant departure from the single-particle Schmidt values. The departure, however, is difficult to evaluate precisely since, as will be seen, it results from a sensitive cancellation between several competing corrections each of which can be as large as the observed discrepancy. This, then, is the continuing fascination of magnetic moments. In this contribution, we revisit the subjet principally to identify the role played by isobar currents, which are of much concern at this conference. But in so doing we warn quite strongly of the dangers of considering just isobar currents in isolation; equal consideration must be given to competing processes which in this context are the mundane nuclear structure effects, such as core polarization, and the more popular meson-exchange currents

  20. Revisiting energy efficiency fundamentals

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Lombard, L.; Velazquez, D. [Grupo de Termotecnia, Escuela Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos s/n, 41092 Seville (Spain); Ortiz, J. [Building Research Establishment (BRE), Garston, Watford, WD25 9XX (United Kingdom)

    2013-05-15

    Energy efficiency is a central target for energy policy and a keystone to mitigate climate change and to achieve a sustainable development. Although great efforts have been carried out during the last four decades to investigate the issue, focusing into measuring energy efficiency, understanding its trends and impacts on energy consumption and to design effective energy efficiency policies, many energy efficiency-related concepts, some methodological problems for the construction of energy efficiency indicators (EEI) and even some of the energy efficiency potential gains are often ignored or misunderstood, causing no little confusion and controversy not only for laymen but even for specialists. This paper aims to revisit, analyse and discuss some efficiency fundamental topics that could improve understanding and critical judgement of efficiency stakeholders and that could help in avoiding unfounded judgements and misleading statements. Firstly, we address the problem of measuring energy efficiency both in qualitative and quantitative terms. Secondly, main methodological problems standing in the way of the construction of EEI are discussed, and a sequence of actions is proposed to tackle them in an ordered fashion. Finally, two key topics are discussed in detail: the links between energy efficiency and energy savings, and the border between energy efficiency improvement and renewable sources promotion.

  1. Kuyper and Apartheid: A revisiting

    African Journals Online (AJOL)

    UPuser

    Kuyper and Apartheid: A revisiting. Patrick Baskwell (Brandon, Florida, USA) .... conflicts. Such was the tradition of apocalyptic fanaticism which – secularised and revivified – was inherited by Lenin and by Hitler. (Cohn 1961:309-310). 3. FERTILE SOIL. This amalgamation ..... Israel did for the Arabs. The first Boer nationalist ...

  2. Revisiting Inter-Genre Similarity

    DEFF Research Database (Denmark)

    Sturm, Bob L.; Gouyon, Fabien

    2013-01-01

    We revisit the idea of ``inter-genre similarity'' (IGS) for machine learning in general, and music genre recognition in particular. We show analytically that the probability of error for IGS is higher than naive Bayes classification with zero-one loss (NB). We show empirically that IGS does...

  3. Spinning pipe gas lens revisited

    CSIR Research Space (South Africa)

    Mafusire, C

    2008-01-01

    Full Text Available , there is little information on optical phase aberrations and no study to date on the propagation parameters of the laser beam, but has rather remained rooted in the domain of ray optics. Researchers revisit the spinning pipe gas lens in this paper with new...

  4. A remote coal deposit revisited

    DEFF Research Database (Denmark)

    Bojesen-Kofoed, Jørgen A.; Kalkreuth, Wolfgang; Petersen, Henrik I.

    2012-01-01

    In 1908, members of the “Danmark Expedition” discovered a coal deposit in a very remote area in western Germania Land, close to the margin of the inland ice in northeast Greenland. The deposit was, however, neither sampled nor described, and was revisited in 2009 for the first time since its...

  5. Membrane dynamics

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    Current topics include membrane-protein interactions with regard to membrane deformation or curvature sensing by BAR domains. Also, we study the dynamics of membrane tubes of both cells and simple model membrane tubes. Finally, we study membrane phase behavior which has important implications...

  6. Reticulin immunostaining revisited

    Directory of Open Access Journals (Sweden)

    Kara Melissa T Torres

    2016-01-01

    Full Text Available Introduction: Reticulin staining has been suggested as an inexpensive tool in the differential diagnosis of melanoma versus benign nevi. In the present study, reticulin immunostaining patterns in malignant melanomas, benign intradermal nevi, and blue nevi were observed. The concordance in evaluation of the pattern between observers was also done. Materials and Methods: A retrospective search was performed in the computer database of the Ackerman Academy of Dermatopathology for “melanoma,” “melanocytic nevus,” and “blue nevus”. Fifty-six melanomas (30 of nodular subtype and 26 of superficial spreading subtype, 54 benign compound nevi, and 27 blue nevi were selected for the study. Patterns of reticulin staining in the dermis and the basement membrane in these melanocytic lesions were evaluated and the concordance between the two groups of authors was assessed. Statistical evaluation was performed with the Statistica® 10 program, Tulsa, OK. Concordance of the pattern evaluation was evaluated using Cohen's kappa coefficient. Results: Melanomas show a variable basement membrane pattern some of which show flat, thin and smooth pattern. Benign nevi almost never showed this flat pattern at the basement membrane zone. In the dermis, melanomas showed reticulin fibers surrounding groups of melanocytic cells while nevi predominantly had reticulin fibers around individual cells. There was greater agreement in evaluating the dermal component compared to the basement membrane pattern. Conclusion: The dermal reticulin staining pattern may be of some value in the diagnosis of melanocytic lesions, but poor concordance in evaluation of the basement membrane zone pattern limits its usefulness.

  7. Izmit Foreshocks Revisited

    Science.gov (United States)

    Ellsworth, W. L.; Bulut, F.

    2016-12-01

    Much of what we know about the initiation of earthquakes comes from the temporal and spatial relationship of foreshocks to the initiation point of the mainshock. The 1999 Mw 7.6 Izmit, Turkey, earthquake was preceded by a 44 minute-long foreshock sequence. Bouchon et al. (Science, 2011) analyzed the foreshocks using a single seismic station, UCG, located to the north of the east-west fault, and concluded on the basis of waveform similarity that the foreshocks repeatedly re-ruptured the same fault patch, driven by slow slip at the base of the crust. We revisit the foreshock sequence using seismograms from 9 additional stations that recorded the four largest foreshocks (Mw 2.0 to 2.8) to better characterize spatial and temporal evolution of the foreshock sequence and their relationship to the mainshock hypocenter. Cross-correlation timing and hypocentroid location with hypoDD reveals a systematic west-to-east propagation of the four largest foreshocks toward the mainshock hypocenter. Foreshock rupture dimensions estimated using spectral ratios imply no major overlap for the first three foreshocks. The centroid of 4th and largest foreshock continues the eastward migration, but lies within the circular source area of the 3rd. The 3rd, however, has a low stress drop and strong directivity to the west . The mainshock hypocenter locates on the eastern edge of foreshock 4. We also re-analyzed waveform similarity of all 18 foreshocks recorded at UCG by removing the common mode signal and clustering the residual seismogram using the correlation coefficient as the distance metric. The smaller foreshocks cluster with the larger events in time order, sometimes as foreshocks and more commonly as aftershocks. These observations show that the Izmit foreshock sequence is consistent with a stress-transfer driven cascade, moving systematically to the east along the fault and that there is no observational requirement for creep as a driving mechanism.

  8. Endocannabinoid transport revisited.

    Science.gov (United States)

    Nicolussi, Simon; Gertsch, Jürg

    2015-01-01

    Endocannabinoids are arachidonic acid-derived endogenous lipids that activate the endocannabinoid system which plays a major role in health and disease. The primary endocannabinoids are anandamide (AEA, N-arachidonoylethanolamine) and 2-arachidonoyl glycerol. While their biosynthesis and metabolism have been studied in detail, it remains unclear how endocannabinoids are transported across the cell membrane. In this review, we critically discuss the different models of endocannabinoid trafficking, focusing on AEA cellular uptake which is best studied. The evolution of the current knowledge obtained with different AEA transport inhibitors is reviewed and the confusions caused by the lack of their specificity discussed. A comparative summary of the most important AEA uptake inhibitors and the studies involving their use is provided. Based on a comprehensive literature analysis, we propose a model of facilitated AEA membrane transport followed by intracellular shuttling and sequestration. We conclude that novel and more specific probes will be essential to identify the missing targets involved in endocannabinoid membrane transport. © 2015 Elsevier Inc. All rights reserved.

  9. Dynamic Topography Revisited

    Science.gov (United States)

    Moresi, Louis

    2015-04-01

    Dynamic Topography Revisited Dynamic topography is usually considered to be one of the trinity of contributing causes to the Earth's non-hydrostatic topography along with the long-term elastic strength of the lithosphere and isostatic responses to density anomalies within the lithosphere. Dynamic topography, thought of this way, is what is left over when other sources of support have been eliminated. An alternate and explicit definition of dynamic topography is that deflection of the surface which is attributable to creeping viscous flow. The problem with the first definition of dynamic topography is 1) that the lithosphere is almost certainly a visco-elastic / brittle layer with no absolute boundary between flowing and static regions, and 2) the lithosphere is, a thermal / compositional boundary layer in which some buoyancy is attributable to immutable, intrinsic density variations and some is due to thermal anomalies which are coupled to the flow. In each case, it is difficult to draw a sharp line between each contribution to the overall topography. The second definition of dynamic topography does seem cleaner / more precise but it suffers from the problem that it is not measurable in practice. On the other hand, this approach has resulted in a rich literature concerning the analysis of large scale geoid and topography and the relation to buoyancy and mechanical properties of the Earth [e.g. refs 1,2,3] In convection models with viscous, elastic, brittle rheology and compositional buoyancy, however, it is possible to examine how the surface topography (and geoid) are supported and how different ways of interpreting the "observable" fields introduce different biases. This is what we will do. References (a.k.a. homework) [1] Hager, B. H., R. W. Clayton, M. A. Richards, R. P. Comer, and A. M. Dziewonski (1985), Lower mantle heterogeneity, dynamic topography and the geoid, Nature, 313(6003), 541-545, doi:10.1038/313541a0. [2] Parsons, B., and S. Daly (1983), The

  10. Perekonnaseadus nõrgema kaitsel / Andra Olm

    Index Scriptorium Estoniae

    Olm, Andra

    2008-01-01

    Uuest perekonnaseaduse eelnõust. Ilmunud ka Lõunaleht 13. märts 2008, lk. 2 ; Meie Maa 13. märts 2008, lk. 2 ; Põhjarannik 13. märts 2008, lk. 2 ; Narva Postiljon 15. märts 2008, lk. 2 ; Koit 18. märts 2008, lk. 4 ; Vooremaa 18. märts 2008, lk. 2 ; Sama ka Järva Teataja 25. märts 2008, lk. 2 ; Kuulutaja 20. märts 2008, lk. 4 ; Vali Uudised 28. märts 2008, lk. 2 ; Elva Postipoiss 29. märts 2008, lk. 4

  11. Membrane fusion

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    At Stanford University, Boxer lab, I worked on membrane fusion of small unilamellar lipid vesicles to flat membranes tethered to glass surfaces. This geometry closely resembles biological systems in which liposomes fuse to plasma membranes. The fusion mechanism was studied using DNA zippering...... between complementary strands linked to the two apposing membranes closely mimicking the zippering mechanism of SNARE fusion complexes....

  12. Biobased Membrane

    NARCIS (Netherlands)

    Koenders, E.A.B.; Zlopasa, J.; Picken, S.J.

    2015-01-01

    The present invention is in the field of a composition for forming a bio-compatible membrane applicable to building material, such as concrete, cement, etc., to a meth od of applying said composition for forming a bio-compatible membrane, a biocompatible membrane, use of said membrane for various

  13. Leadership and Management Theories Revisited

    OpenAIRE

    Madsen, Mona Toft

    2001-01-01

    The goal of the paper is to revisit and analyze key contributions to the understanding of leadership and management. As a part of the discussion a role perspective that allows for additional and/or integrated leader dimensions, including a change-centered, will be outlined. Seemingly, a major challenge on the substantive level is the integration of soft and hard managerial functions, while the concepts used in presenting these should at least in transition be able to contain a distinction bet...

  14. Leadership and Management Theories Revisited

    OpenAIRE

    Madsen, Mona Toft

    2001-01-01

    The goal of this paper is to revisit and analyze key contributions to the understanding of leadership and to discuss the relevance of maintaining a distinct line of demarcation between leadership and management. As a part of the discussion a role perspective that allows for additional and/or integrated leader dimensions, including a change-centered, will be outlined. Seemingly, a major challenge on the substantive level is the integration of soft and hard managerial functions, while the conce...

  15. Membranous nephropathy

    Science.gov (United States)

    ... check for hepatitis B, hepatitis C, and syphilis Complement levels Cryoglobulin test Treatment The goal of treatment ... not as helpful for people with membranous nephropathy. Medicines used treat membranous nephropathy include: Angiotensin-converting enzyme ( ...

  16. Leadership and Management Theories Revisited

    DEFF Research Database (Denmark)

    Madsen, Mona Toft

    2001-01-01

    The goal of the paper is to revisit and analyze key contributions to the understanding of leadership and management. As a part of the discussion a role perspective that allows for additional and/or integrated leader dimensions, including a change-centered, will be outlined. Seemingly, a major...... challenge on the substantive level is the integration of soft and hard managerial functions, while the concepts used in presenting these should at least in transition be able to contain a distinction between hard, soft, and general practices....

  17. Hong Kong's Consumption Function Revisited

    OpenAIRE

    Li-gang Liu; Laurent Pauwels; Andrew Tsang

    2007-01-01

    This paper revisits the relationship among consumption, income and wealth using Hong Kong data. We find that the permanent income hypothesis is weakly supported by Hong Kong¡¦s consumption data prior to 1997, but it is not supported for the sample period after 1997 and the whole sample period spanning from 1984 to 2006. Furthermore, we find that both anticipated and unanticipated income and wealth effects have influences on Hong Kong¡¦s consumption. While temporary tax changes may have some i...

  18. Membrane Biophysics

    CERN Document Server

    Ashrafuzzaman, Mohammad

    2013-01-01

    Physics, mathematics and chemistry all play a vital role in understanding the true nature and functioning of biological membranes, key elements of living processes. Besides simple spectroscopic observations and electrical measurements of membranes we address in this book the phenomena of coexistence and independent existence of different membrane components using various theoretical approaches. This treatment will be helpful for readers who want to understand biological processes by applying both simple observations and fundamental scientific analysis. It provides a deep understanding of the causes and effects of processes inside membranes, and will thus eventually open new doors for high-level pharmaceutical approaches towards fighting membrane- and cell-related diseases.

  19. Tourists' perceptions and intention to revisit Norway

    OpenAIRE

    Lazar, Ana Florina; Komolikova-Blindheim, Galyna

    2016-01-01

    Purpose - The overall purpose of this study is to explore tourists' perceptions and their intention to revisit Norway. The aim is to find out what are the factors that drive the overall satisfaction, the willingness to recommend and the revisit intention of international tourists that spend their holiday in Norway. Design-Method-Approach - the Theory of Planned Behavior (Ajzen 1991), is used as a framework to investigate tourists' intention and behavior towards Norway as destination. The o...

  20. 42 CFR 488.30 - Revisit user fee for revisit surveys.

    Science.gov (United States)

    2010-10-01

    ... Provisions § 488.30 Revisit user fee for revisit surveys. (a) Definitions. As used in this section, the following definitions apply: Certification (both initial and recertification) means those activities as... allegation of noncompliance, as defined in § 488.1. Provider of services, provider, or supplier has the...

  1. LAURDAN fluorescence properties in membranes: a journey from the fluorometer to the microscope

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2012-01-01

    After 32 years since its introduction, the particular fluorescence properties of 6-lauroyl-2-(dimethylamino)-naphtalene (LAURDAN) in model and biological membranes are revisited. This review includes a historical perspective about the design, synthesis and initial description of the probe’s fluor...

  2. The power reinforcement framework revisited

    DEFF Research Database (Denmark)

    Nielsen, Jeppe; Andersen, Kim Normann; Danziger, James N.

    2016-01-01

    public organizations. This article revisits the 30-yearold power reinforcement framework by means of an empirical analysis on the use of mobile technology in a large-scale programme in Danish public sector home care. It explores whether and to what extent administrative management has controlled decision......-dominated and centrally controlled technologies that were the main focus of the 1970s and 1980s studies. Yet this study concludes that there is general support for the reinforcement framework in the contemporary application of mobile technology in public sector home care.......-making and gained most benefits from mobile technology use, relative to the effects of the technology on the street-level workers who deliver services. Current mobile technology-in-use might be less likely to be power reinforcing because it is far more decentralized and individualized than the mainly expert...

  3. The Levy sections theorem revisited

    International Nuclear Information System (INIS)

    Figueiredo, Annibal; Gleria, Iram; Matsushita, Raul; Silva, Sergio Da

    2007-01-01

    This paper revisits the Levy sections theorem. We extend the scope of the theorem to time series and apply it to historical daily returns of selected dollar exchange rates. The elevated kurtosis usually observed in such series is then explained by their volatility patterns. And the duration of exchange rate pegs explains the extra elevated kurtosis in the exchange rates of emerging markets. In the end, our extension of the theorem provides an approach that is simpler than the more common explicit modelling of fat tails and dependence. Our main purpose is to build up a technique based on the sections that allows one to artificially remove the fat tails and dependence present in a data set. By analysing data through the lenses of the Levy sections theorem one can find common patterns in otherwise very different data sets

  4. Secret Public Key Protocols Revisited

    Science.gov (United States)

    Lim, Hoon Wei; Paterson, Kenneth G.

    Password-based protocols are important and popular means of providing human-to-machine authentication. The concept of secret public keys was proposed more than a decade ago as a means of securing password-based authentication protocols against off-line password guessing attacks, but was later found vulnerable to various attacks. In this paper, we revisit the concept and introduce the notion of identity-based secret public keys. Our new identity-based approach allows secret public keys to be constructed in a very natural way using arbitrary random strings, eliminating the structure found in, for example, RSA or ElGamal keys. We examine identity-based secret public key protocols and give informal security analyses, indicating that they are secure against off-line password guessing and other attacks.

  5. Membrane paradigm

    International Nuclear Information System (INIS)

    Price, R.H.; Thorne, K.S.

    1986-01-01

    The membrane paradigm is a modified frozen star approach to modeling black holes, with particles and fields assuming a complex, static, boundary-layer type structure (membrane) near the event horizon. The membrane has no effects on the present or future evolution of particles and fields above itself. The mathematical representation is a combination of a formalism containing terms for the shear and bulk viscosity, surface pressure, momentum, temperature, entropy, etc., of the horizon and the 3+1 formalism. The latter model considers a family of three-dimensional spacelike hypersurfaces in one-dimensional time. The membrane model considers a magnetic field threading the hole and undergoing torque from the hole rotation. The field is cleaned by the horizon and distributed over the horizon so that ohmic dissipation is minimized. The membrane paradigm is invalid inside the horizon, but is useful for theoretically probing the properties of slowly evolving black holes

  6. Membrane processes

    Science.gov (United States)

    Staszak, Katarzyna

    2017-11-01

    The membrane processes have played important role in the industrial separation process. These technologies can be found in all industrial areas such as food, beverages, metallurgy, pulp and paper, textile, pharmaceutical, automotive, biotechnology and chemical industry, as well as in water treatment for domestic and industrial application. Although these processes are known since twentieth century, there are still many studies that focus on the testing of new membranes' materials and determining of conditions for optimal selectivity, i. e. the optimum transmembrane pressure (TMP) or permeate flux to minimize fouling. Moreover the researchers proposed some calculation methods to predict the membrane processes properties. In this article, the laboratory scale experiments of membrane separation techniques, as well their validation by calculation methods are presented. Because membrane is the "heart" of the process, experimental and computational methods for its characterization are also described.

  7. Primordial membranes

    DEFF Research Database (Denmark)

    Hanczyc, Martin M; Monnard, Pierre-Alain

    2017-01-01

    Cellular membranes, which are self-assembled bilayer structures mainly composed of lipids, proteins and conjugated polysaccharides, are the defining feature of cell physiology. It is likely that the complexity of contemporary cells was preceded by simpler chemical systems or protocells during...... the various evolutionary stages that led from inanimate to living matter. It is also likely that primitive membranes played a similar role in protocell 'physiology'. The composition of such ancestral membranes has been proposed as mixtures of single hydrocarbon chain amphiphiles, which are simpler versions...

  8. Revisiting tourist behavior via destination brand worldness

    Directory of Open Access Journals (Sweden)

    Murat Kayak

    2016-11-01

    Full Text Available Taking tourists’ perspective rather than destination offerings as its core concept, this study introduces “perceived destination brand worldness” as a variable. Perceived destination brand worldness is defined as the positive perception that a tourist has of a country that is visited by tourists from all over the world. Then, the relationship between perceived destination brand worldness and intention to revisit is analyzed using partial least squares regression. This empirical study selects Taiwanese tourists as its sample, and the results show that perceived destination brand worldness is a direct predictor of intention to revisit. In light of these empirical findings and observations, practical and theoretical implications are discussed.

  9. Leukemia and ionizing radiation revisited

    Energy Technology Data Exchange (ETDEWEB)

    Cuttler, J.M. [Cuttler & Associates Inc., Vaughan, Ontario (Canada); Welsh, J.S. [Loyola University-Chicago, Dept. or Radiation Oncology, Stritch School of Medicine, Maywood, Illinois (United States)

    2016-03-15

    A world-wide radiation health scare was created in the late 19508 to stop the testing of atomic bombs and block the development of nuclear energy. In spite of the large amount of evidence that contradicts the cancer predictions, this fear continues. It impairs the use of low radiation doses in medical diagnostic imaging and radiation therapy. This brief article revisits the second of two key studies, which revolutionized radiation protection, and identifies a serious error that was missed. This error in analyzing the leukemia incidence among the 195,000 survivors, in the combined exposed populations of Hiroshima and Nagasaki, invalidates use of the LNT model for assessing the risk of cancer from ionizing radiation. The threshold acute dose for radiation-induced leukemia, based on about 96,800 humans, is identified to be about 50 rem, or 0.5 Sv. It is reasonable to expect that the thresholds for other cancer types are higher than this level. No predictions or hints of excess cancer risk (or any other health risk) should be made for an acute exposure below this value until there is scientific evidence to support the LNT hypothesis. (author)

  10. Individualist Biocentrism vs. Holism Revisited

    Directory of Open Access Journals (Sweden)

    Katie McShane

    2014-06-01

    Full Text Available While holist views such as ecocentrism have considerable intuitive appeal, arguing for the moral considerability of ecological wholes such as ecosystems has turned out to be a very difficult task. In the environmental ethics literature, individualist biocentrists have persuasively argued that individual organisms—but not ecological wholes—are properly regarded as having a good of their own . In this paper, I revisit those arguments and contend that they are fatally flawed. The paper proceeds in five parts. First, I consider some problems brought about by climate change for environmental conservation strategies and argue that these problems give us good pragmatic reasons to want a better account of the welfare of ecological wholes. Second, I describe the theoretical assumptions from normative ethics that form the background of the arguments against holism. Third, I review the arguments given by individualist biocentrists in favour of individualism over holism. Fourth, I review recent work in the philosophy of biology on the units of selection problem, work in medicine on the human biome, and work in evolutionary biology on epigenetics and endogenous viral elements. I show how these developments undermine both the individualist arguments described above as well as the distinction between individuals and wholes as it has been understood by individualists. Finally, I consider five possible theoretical responses to these problems.

  11. Neutrino assisted GUT baryogenesis revisited

    Science.gov (United States)

    Huang, Wei-Chih; Päs, Heinrich; Zeißner, Sinan

    2018-03-01

    Many grand unified theory (GUT) models conserve the difference between the baryon and lepton number, B -L . These models can create baryon and lepton asymmetries from heavy Higgs or gauge boson decays with B +L ≠0 but with B -L =0 . Since the sphaleron processes violate B +L , such GUT-generated asymmetries will finally be washed out completely, making GUT baryogenesis scenarios incapable of reproducing the observed baryon asymmetry of the Universe. In this work, we revisit the idea to revive GUT baryogenesis, proposed by Fukugita and Yanagida, where right-handed neutrinos erase the lepton asymmetry before the sphaleron processes can significantly wash out the original B +L asymmetry, and in this way one can prevent a total washout of the initial baryon asymmetry. By solving the Boltzmann equations numerically for baryon and lepton asymmetries in a simplified 1 +1 flavor scenario, we can confirm the results of the original work. We further generalize the analysis to a more realistic scenario of three active and two right-handed neutrinos to highlight flavor effects of the right-handed neutrinos. Large regions in the parameter space of the Yukawa coupling and the right-handed neutrino mass featuring successful baryogenesis are identified.

  12. Revisiting the formal foundation of Probabilistic Databases

    NARCIS (Netherlands)

    Wanders, B.; van Keulen, Maurice

    2015-01-01

    One of the core problems in soft computing is dealing with uncertainty in data. In this paper, we revisit the formal foundation of a class of probabilistic databases with the purpose to (1) obtain data model independence, (2) separate metadata on uncertainty and probabilities from the raw data, (3)

  13. Residual Momentum and Reversal Strategies Revisited

    NARCIS (Netherlands)

    J.J. Huij (Joop); S.D. Lansdorp (Simon)

    2017-01-01

    textabstractIn this note we revisit the 2011 and 2013 papers of Blitz, Huij, and Martens (BHM2011), and Blitz, Huij, Lansdorp, and Verbeek (BHLV2013) in which momentum and reversal strategies on residual returns are proposed. Our results indicate that the main findings of these studies, that

  14. Mofolo's Chaka revisited via the original text

    African Journals Online (AJOL)

    oi, oi! … you must go by the right path': Mofolo's Chaka revisited via the original text. Thomas Mofolo never defended himself against accusations that his novel Chaka distorts historical facts to express anti-Nguni sentiments under the guise of Christianity. But in a way he foreshadowed the possibility of it, by including as part ...

  15. Revisiting Hansen Solubility Parameters by Including Thermodynamics

    NARCIS (Netherlands)

    Louwerse, Manuel J; Fernández-Maldonado, Ana María; Rousseau, Simon; Moreau-Masselon, Chloe; Roux, Bernard; Rothenberg, Gadi

    2017-01-01

    The Hansen solubility parameter approach is revisited by implementing the thermodynamics of dissolution and mixing. Hansen's pragmatic approach has earned its spurs in predicting solvents for polymer solutions, but for molecular solutes improvements are needed. By going into the details of entropy

  16. The Pills problem revisited | Brennan | Quaestiones Mathematicae

    African Journals Online (AJOL)

    We revisit the pills problem proposed by Knuth and McCarthy. In a bottle there are m large pills and n small pills. The large pill is equivalent to two small pills. ... Mathematics Subject Classification (2000): Primary: 05A15; Secondary: 60C05. Key words: Pills problem, recursions, harmonic numbers, generating functions.

  17. Offset steering in multiamp ion sources - revisited

    International Nuclear Information System (INIS)

    Ott, W.

    1993-01-01

    Steering of the individual beamlets in multiamp ion beams by offsetting the axes of circular extraction holes in three-electrode acceleration systems is revisited. A consistent application of the Langmuir-Blodgett theory of a spherical diode gives a stronger deflection per unit offset than assumed hitherto. (orig.)

  18. Revisiting Weak Simulation for Substochastic Markov Chains

    DEFF Research Database (Denmark)

    Jansen, David N.; Song, Lei; Zhang, Lijun

    2013-01-01

    of the logic PCTL\\x, and its completeness was conjectured. We revisit this result and show that soundness does not hold in general, but only for Markov chains without divergence. It is refuted for some systems with substochastic distributions. Moreover, we provide a counterexample to completeness...

  19. Coccolithophorids in polar waters: Wigwamma spp. revisited

    DEFF Research Database (Denmark)

    Thomsen, Helge Abildhauge; Østergaard, Jette B.; Heldal, Mikal

    2013-01-01

    A contingent of weakly calcified coccolithophorid genera and species were described from polar regions almost 40 years ago. In the interim period a few additional findings have been reported enlarging the realm of some of the species. The genus Wigwamma is revisited here with the purpose of provi...... appearance of the coccolith armour of the cell...

  20. Revisiting the stratigraphy of the Mesoproterozoic Chhattisgarh ...

    Indian Academy of Sciences (India)

    The present work supports the existence of two sub-basins separated .... Updated geological map of the Chhattisgarh basin (this work). Cross sections along ..... Conclusion. This revisiting of the stratigraphy of Chhattisgarh. Supergroup requires three major corrections to the standard model (GSI 2005; Naqvi 2005). First, the.

  1. Revisiting the importance of childhood activity

    African Journals Online (AJOL)

    2012-11-05

    Nov 5, 2012 ... Review Article: Revisiting the importance of childhood activity. 249. Vol 55 No 3. S Afr Fam Pract 2013. Introduction. There has been a drastic increase in documented childhood morbidity and mortality relating to poor nutrition, obesity and low activity levels in recent years. Formalised exercise programmes ...

  2. Revisiting separation properties of convex fuzzy sets

    Science.gov (United States)

    Separation of convex sets by hyperplanes has been extensively studied on crisp sets. In a seminal paper separability and convexity are investigated, however there is a flaw on the definition of degree of separation. We revisited separation on convex fuzzy sets that have level-wise (crisp) disjointne...

  3. The Evil of Banality: Arendt Revisited

    Science.gov (United States)

    Minnich, Elizabeth

    2014-01-01

    "The banality of evil" (Arendt) remains controversial and useful. Ironically, the concept is now itself a banality. To revisit and extend it, we consider the "evil of banality", the profound dangers of cliched thoughtlessness. A distinction is proposed: "intensive" versus "extensive evils". The former takes…

  4. The Faraday effect revisited: General theory

    DEFF Research Database (Denmark)

    Cornean, Horia Decebal; Nenciu, Gheorghe; Pedersen, Thomas Garm

    This paper is the first in a series revisiting the Faraday effect, or more generally, the theory of electronic quantum transport/optical response in bulk media in the presence of a constant magnetic field. The independent electron approximation is assumed. For free electrons, the transverse...

  5. eWOM, Revisit Intention, Destination Trust and Gender

    OpenAIRE

    Abubakar, Abubakar Mohammed; Ilkan, Mustafa; Al-Tal, Raad Meshall; Eluwole, Kayode

    2017-01-01

    This article investigates the impact of eWOM on intention to revisit and destination trust, and the moderating role of gender in medical tourism industry. Result from structural equation modeling (n=240) suggests the following: (1) that eWOM influences intention to revisit and destination trust; (2) that destination trust influences intention to revisit; (3) that the impact of eWOM on intention to revisit is about 1.3 times higher in men; (4) that the impact of eWOM on destination trust is ab...

  6. Robotic membranes

    DEFF Research Database (Denmark)

    Ramsgaard Thomsen, Mette

    2008-01-01

    , Vivisection and Strange Metabolisms, were developed at the Centre for Information Technology and Architecture (CITA) at the Royal Danish Academy of Fine Arts in Copenhagen as a means of engaging intangible digital data with tactile physical material. As robotic membranes, they are a dual examination...

  7. Revisiting the Harris-Hatang Dialogue

    African Journals Online (AJOL)

    Revisiting the Harris-Hatang Dialogue: A Critique of “What it (Might) Mean(s) to be an African Archivist” ... A city rich in culture that for once forced me to wish that I should have been a sociologist or anthropologist. The idea of Zanzibar as an archives never crossed my mind. Harris still has to convince me about that. This kind ...

  8. Revisiting Cementoblastoma with a Rare Case Presentation

    Directory of Open Access Journals (Sweden)

    Vijayanirmala Subramani

    2017-01-01

    Full Text Available Cementoblastoma is a rare benign odontogenic neoplasm which is characterized by the proliferation of cellular cementum. Diagnosis of cementoblastoma is challenging because of its protracted clinical, radiographic features, and bland histological appearance; most often cementoblastoma is often confused with other cementum and bone originated lesions. The aim of this article is to overview/revisit, approach the diagnosis of cementoblastoma, and also present a unique radiographic appearance of a cementoblastoma lesion associated with an impacted tooth.

  9. FACTORS INFLUENCING TOURISTS’ REVISIT TO BALI AS MICE DESTINATION

    Directory of Open Access Journals (Sweden)

    Ni Made Eka Mahadewi

    2014-07-01

    Full Text Available Plan to revisit of MICE tourists has been highlighted as an important research topic in competitive market of tourism destinations especially in MICE Destination. Despite the considerable number of research on MICE tourists, it remains unclear why MICE tourists undertake to plan their repeated visits and what kind of indicators influenced. This research aims to identify factors influencing MICE tourists to revisit to Bali – Indonesia. By using SEM (Structural Equation Model, one of the results of this study indicated that MICE Destination’s attribute, Promotion, Satisfaction and Image were the important factor to affect Revisit of MICE tourists to come again or revisit to Bali as MICE Destination. Concerning with MICE tourists perception on revisit; tourist visit to Bali for MICE destination can be enhanced by promotion through image of Bali.

  10. Development of Pd-Ag Compostie Membrane for Separation of Hydrogen at Elevated Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Shamsuddin Ilias

    2009-02-28

    Pd-based membrane reactor offers the possibility of combining reaction and separation in a single operation at high temperatures to overcome the equilibrium limitations experienced in conventional reactor configurations. In this project to develop a defect-free and hermally-stable Pd-film on microporous stainless steel (MPSS) support for H2-separation and membrane reactor applications, the electroless plating process was revisited with an aim to improve the membrane morphology. Specifically, this study includes; (a) an improvement f activation step using Pulse Laser Deposition (PLD), (b) development of a novel surfactant induced electroless plating (SIEP) for depositing robust Pd-film on microporous support, and (c) application of Pd-membrane as membrane reactor in steam methanol reforming (SMR) reactions.

  11. Revisiting the Political Economy of Communication

    Directory of Open Access Journals (Sweden)

    Nicholas Garnham

    2014-02-01

    The task of the paper and the seminar was to revisit some of Nicholas Garnham’s ideas, writings and contributions to the study of the Political Economy of Communication and to reflect on the concepts, history, current status and perspectives of this field and the broader study of political economy today. The topics covered include Raymond Williams’ cultural materialism, Pierre Bourdieu’s sociology of culture, the debate between Political Economy and Cultural Studies, information society theory, Karl Marx’s theory and the critique of capitalism.

  12. Large J expansion in ABJM theory revisited.

    Science.gov (United States)

    Dimov, H; Mladenov, S; Rashkov, R C

    Recently there has been progress in the computation of the anomalous dimensions of gauge theory operators at strong coupling by making use of the AdS/CFT correspondence. On the string theory side they are given by dispersion relations in the semiclassical regime. We revisit the problem of a large-charge expansion of the dispersion relations for simple semiclassical strings in an [Formula: see text] background. We present the calculation of the corresponding anomalous dimensions of the gauge theory operators to an arbitrary order using three different methods. Although the results of the three methods look different, power series expansions show their consistency.

  13. The Faraday effect revisited: General theory

    DEFF Research Database (Denmark)

    Cornean, Horia Decebal; Nenciu, Gheorghe; Pedersen, Thomas Garm

    2006-01-01

    This paper is the first in a series revisiting the Faraday effect, or more generally, the theory of electronic quantum transport/optical response in bulk media in the presence of a constant magnetic field. The independent electron approximation is assumed. At zero temperature and zero frequency......, if the Fermi energy lies in a spectral gap, we rigorously prove theWidom-Streda formula. For free electrons, the transverse conductivity can be explicitly computed and coincides with the classical result. In the general case, using magnetic perturbation theory, the conductivity tensor is expanded in powers...

  14. Sloan Digital Sky Survey Photometric Calibration Revisited

    International Nuclear Information System (INIS)

    Marriner, John

    2012-01-01

    The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.

  15. Sloan Digital Sky Survey Photometric Calibration Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Marriner, John; /Fermilab

    2012-06-29

    The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.

  16. Molecular Interactions at Membranes

    DEFF Research Database (Denmark)

    Jagalski, Vivien

    Biological membranes are essential and complex structures in every living cell consisting of a fluid lipid bilayer sheet and membrane proteins. Its significance makes biological membranes not only interesting for medical research, but also has made it a target for toxins in the course of evolution....... Today, we know more than ever before about the properties of biological membranes. Advanced biophysical techniques and sophisticated membrane models allow us to answer specific questions about the structure of the components within membranes and their interactions. However, many detailed structural...... mechanisms of membrane compounds, including compounds associated with membranes, are still unknown due to the challenges that arise when probing the hydrophobic nature of the membrane's interior. For integral membrane proteins that span through the entire membrane, the amphiphilic environment is essential...

  17. The role of brand destination experience in determining revisit intention

    DEFF Research Database (Denmark)

    Mattsson, Jan; Barnes, Stuart; Sørensen, Flemming

    experience, which provides a more holistic and unified view of the brand destination. The research uses a logistic regression model to determine the role of satisfaction and brand experience in determining revisit intentions. The study also examines differences among subgroups and four brand experience sub......-constructs. The findings suggest that brand experience is an important determinant of revisit intentions, but that there is variation among respondent groups. The paper rounds off with conclusions and implications for research and practice....

  18. Magnetically controlled permeability membranes

    KAUST Repository

    Kosel, Jurgen

    2013-10-31

    A bioactive material delivery system can include a thermoresponsive polymer membrane and nanowires distributed within the thermoresponsive polymer membrane. Magnetic activation of a thermoresponsive polymer membrane can take place via altering the magnetization or dimensions of nanowires dispersed or ordered within the membrane matrix.

  19. OLMS: Online Learning Management System for E-Learning

    Science.gov (United States)

    Ippakayala, Vinay Kumar; El-Ocla, Hosam

    2017-01-01

    In this paper we introduce a learning management system that provides a management system for centralized control of course content. A secure system to record lectures is implemented as a key feature of this application. This feature would be accessed through web camera and mobile recording. These features are mainly designed for e-learning…

  20. Polymeric Membrane Reactors

    OpenAIRE

    José M. Sousa; Luís M. Madeira; João C. Santos; Adélio Mendes

    2008-01-01

    The aim of this chapter is the study of membrane reactors with polymeric membranes, particularly catalytic polymeric membranes. After an introduction where the main advantages and disadvantages of the use of polymeric membranes are summarised, a review of the main areas where they have been applied, integrated in chemical reactors, is presented. This excludes the field of bio-membranes processes, which is analysed in a specific chapter of this book. Particular attention is then given to model...

  1. Revisiting kaon physics in general Z scenario

    Directory of Open Access Journals (Sweden)

    Motoi Endo

    2017-08-01

    Full Text Available New physics contributions to the Z penguin are revisited in the light of the recently-reported discrepancy of the direct CP violation in K→ππ. Interference effects between the standard model and new physics contributions to ΔS=2 observables are taken into account. Although the effects are overlooked in the literature, they make experimental bounds significantly severer. It is shown that the new physics contributions must be tuned to enhance B(KL→π0νν¯, if the discrepancy of the direct CP violation is explained with satisfying the experimental constraints. The branching ratio can be as large as 6×10−10 when the contributions are tuned at the 10% level.

  2. Post-Inflationary Gravitino Production Revisited

    CERN Document Server

    Ellis, John; Nanopoulos, Dimitri V.; Olive, Keith A.; Peloso, Marco

    2016-01-01

    We revisit gravitino production following inflation. As a first step, we review the standard calculation of gravitino production in the thermal plasma formed at the end of post-inflationary reheating when the inflaton has completely decayed. Next we consider gravitino production prior to the completion of reheating, assuming that the inflaton decay products thermalize instantaneously while they are still dilute. We then argue that instantaneous thermalization is in general a good approximation, and also show that the contribution of non-thermal gravitino production via the collisions of inflaton decay products prior to thermalization is relatively small. Our final estimate of the gravitino-to-entropy ratio is approximated well by a standard calculation of gravitino production in the post-inflationary thermal plasma assuming total instantaneous decay and thermalization at a time $t \\simeq 1.2/\\Gamma_\\phi$. Finally, in light of our calculations, we consider potential implications of upper limits on the gravitin...

  3. Mola'a Revisited: Reef Panpipes

    DEFF Research Database (Denmark)

    2017-01-01

    The first main shoot for the Reef Islands Ethnographic Film Series in the Solomon Islands, in 1996, was seriously affected by the un- expected death of one of the main characters and partners in the project, Alfred Melotu, the paramount chief of the Aiwoo-speaking people on the island of Ngasinue....... His death and funeral resulted in the first film we produced from the series, Alfred Melotu – the funeral of a paramount chief (2002), and footage from this plays an import- ant role in the installation film, Passage (2014), that forms a crucial element of the ethnographic exhibition, The Life...... of the Dead, at Moesgaard Museum (MOMU). In 2005 I revisited the Reef Islands and Mola’a, a small settlement on the northern tip of Ngasinue, where Alfred had settled with his extended family only a few years prior to his death. It was mainly a courtesy visit to his descendants, especially Agnes, his widow...

  4. Coccolithophorids in polar waters: Trigonaspis spp. revisited

    DEFF Research Database (Denmark)

    Thomsen, Helge Abildhauge; Østergaard, Jette B.

    2015-01-01

    of crystallites that cover the surfaces of both the tower-shaped flagellar pole coccoliths and the disc-shaped body coccoliths are the keystone features of the genus. Circumstantial evidence exists linking species of Trigonaspis with species of Pappomonas in haploid-diploid life cycles.......A group of weakly calcified coccolithophorid genera and species were described from polar regions several decades ago. In the interim period a few additional findings have been reported adding to the morphological and biogeographical databases of some of the species. The holococcolithophorid genus...... Trigonaspis is revisited here with the purpose of providing, based on additional sampling from both polar regions, an update on species morphology, life history aspects and biogeography. The genus Trigonaspis as currently circumscribed comprises four taxa – two from each polar region. The triangular plates...

  5. Sparse random matrices: The eigenvalue spectrum revisited

    International Nuclear Information System (INIS)

    Semerjian, Guilhem; Cugliandolo, Leticia F.

    2003-08-01

    We revisit the derivation of the density of states of sparse random matrices. We derive a recursion relation that allows one to compute the spectrum of the matrix of incidence for finite trees that determines completely the low concentration limit. Using the iterative scheme introduced by Biroli and Monasson [J. Phys. A 32, L255 (1999)] we find an approximate expression for the density of states expected to hold exactly in the opposite limit of large but finite concentration. The combination of the two methods yields a very simple geometric interpretation of the tails of the spectrum. We test the analytic results with numerical simulations and we suggest an indirect numerical method to explore the tails of the spectrum. (author)

  6. The Faraday effect revisited General theory

    CERN Document Server

    Cornean, H D; Pedersen, T G

    2005-01-01

    This paper is the first in a series revisiting the Faraday effect, or more generally, the theory of electronic quantum transport/optical response in bulk media in the presence of a constant magnetic field. The independent electron approximation is assumed. For free electrons, the transverse conductivity can be explicitly computed and coincides with the classical result. In the general case, using magnetic perturbation theory, the conductivity tensor is expanded in powers of the strength of the magnetic field $B$. Then the linear term in $B$ of this expansion is written down in terms of the zero magnetic field Green function and the zero field current operator. In the periodic case, the linear term in $B$ of the conductivity tensor is expressed in terms of zero magnetic field Bloch functions and energies. No derivatives with respect to the quasimomentum appear and thereby all ambiguities are removed, in contrast to earlier work.

  7. Neutrino dark energy. Revisiting the stability issue

    International Nuclear Information System (INIS)

    Eggers Bjaelde, O.; Hannestad, S.; Schrempp, L.; Tocchini-Valentini, D.

    2007-05-01

    A coupling between a light scalar field and neutrinos has been widely discussed as a mechanism for linking (time varying) neutrino masses and the present energy density and equation of state of dark energy. However, it has been pointed out that the viability of this scenario in the non-relativistic neutrino regime is threatened by the strong growth of hydrodynamic perturbations associated with a negative adiabatic sound speed squared. In this paper we revisit the stability issue in the framework of linear perturbation theory in a model independent way. The criterion for the stability of a model is translated into a constraint on the scalar-neutrino coupling, which depends on the ratio of the energy densities in neutrinos and cold dark matter. We illustrate our results by providing meaningful examples both for stable and unstable models. (orig.)

  8. Revisiting R-invariant direct gauge mediation

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Cheng-Wei [Center for Mathematics and Theoretical Physics andDepartment of Physics, National Central University,Taoyuan, Taiwan 32001, R.O.C. (China); Institute of Physics, Academia Sinica,Taipei, Taiwan 11529, R.O.C. (China); Physics Division, National Center for Theoretical Sciences,Hsinchu, Taiwan 30013, R.O.C. (China); Kavli IPMU (WPI), UTIAS, University of Tokyo,Kashiwa, Chiba 277-8583 (Japan); Harigaya, Keisuke [Department of Physics, University of California,Berkeley, California 94720 (United States); Theoretical Physics Group, Lawrence Berkeley National Laboratory,Berkeley, California 94720 (United States); ICRR, University of Tokyo,Kashiwa, Chiba 277-8582 (Japan); Ibe, Masahiro [Kavli IPMU (WPI), UTIAS, University of Tokyo,Kashiwa, Chiba 277-8583 (Japan); ICRR, University of Tokyo,Kashiwa, Chiba 277-8582 (Japan); Yanagida, Tsutomu T. [Kavli IPMU (WPI), UTIAS, University of Tokyo,Kashiwa, Chiba 277-8583 (Japan)

    2016-03-21

    We revisit a special model of gauge mediated supersymmetry breaking, the “R-invariant direct gauge mediation.” We pay particular attention to whether the model is consistent with the minimal model of the μ-term, i.e., a simple mass term of the Higgs doublets in the superpotential. Although the incompatibility is highlighted in view of the current experimental constraints on the superparticle masses and the observed Higgs boson mass, the minimal μ-term can be consistent with the R-invariant gauge mediation model via a careful choice of model parameters. We derive an upper limit on the gluino mass from the observed Higgs boson mass. We also discuss whether the model can explain the 3σ excess of the Z+jets+E{sub T}{sup miss} events reported by the ATLAS collaboration.

  9. Healthier times?: revisiting Indigenous Australian health history.

    Science.gov (United States)

    Blyton, Greg

    2009-01-01

    The perception that Indigenous Australians were primitive hunters and gatherers who lived in a nomadic 'Stone Age' culture resonates through most narratives found on Indigenous people in pre-colonial times. This narrative is better placed in the realm of myth; I contest claims that the life expectancy of Indigenous Australians was only forty years in pre-colonial times, by providing suggestive evidence that there is a strong probability that longevity favoured Indigenous Australians in comparison to many poorer sectors of the European population living in slum habitats. As well, I will challenge notions that Indigenous Australians were more violent than supposedly 'civilised' nations. Finally I express the hope that future researchers will revisit archival sources to develop a more nuanced perspective on the past.

  10. Revisiting monotop production at the LHC

    International Nuclear Information System (INIS)

    Boucheneb, Idir; Cacciapaglia, Giacomo; Deandrea, Aldo; Fuks, Benjamin

    2015-01-01

    Scenarios of new physics where a single top quark can be produced in association with large missing energy (monotop) have been recently studied both from the theoretical point of view and by experimental collaborations. We revisit the originally proposed monotop setup by embedding the effective couplings of the top quark in an SU(2) L invariant formalism. We show that minimality selects one model for each of the possible production mechanisms: a scalar field coupling to a right-handed top quark and an invisible fermion when the monotop system is resonantly produced, and a vector field mediating the interactions of a dark sector to right-handed quarks for the non-resonant production mode. We study in detail constraints on the second class of scenarios, originating from contributions to standard single top processes when the mediator is lighter than the top quark and from the dark matter relic abundance when the mediator is heavier than the top quark.

  11. Revisiting monotop production at the LHC

    CERN Document Server

    Boucheneb, Idir; Deandrea, Aldo; Fuks, Benjamin

    2015-01-01

    Scenarios of new physics where a single top quark can be produced in association with large missing energy (monotop) have been recently studied both from the theoretical point of view and by experimental collaborations. We revisit the originally proposed monotop setup by embedding the effective couplings of the top quark in an SU(2)L invariant formalism. We show that minimality selects one model for each of the possible production mechanisms: a scalar field coupling to a right-handed top quark and an invisible fermion when the monotop system is resonantly produced, and a vector field mediating the interactions of a dark sector to right-handed quarks for the non-resonant production mode. We study in detail constraints on the second class of scenarios, originating from contributions to standard single top processes when the mediator is lighter than the top quark and from the dark matter relic abundance when the mediator is heavier than the top quark.

  12. Sheet Membrane Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Bue, Grant; Trevino, Luis; Zapata, Felipe; Dillion, Paul; Castillo, Juan; Vonau, Walter; Wilkes, Robert; Vogel, Matthew; Frodge, Curtis

    2013-01-01

    A document describes a sheet membrane spacesuit water membrane evaporator (SWME), which allows for the use of one common water tank that can supply cooling water to the astronaut and to the evaporator. Test data showed that heat rejection performance dropped only 6 percent after being subjected to highly contaminated water. It also exhibited robustness with respect to freezing and Martian atmospheric simulation testing. Water was allowed to freeze in the water channels during testing that simulated a water loop failure and vapor backpressure valve failure. Upon closing the backpressure valve and energizing the pump, the ice eventually thawed and water began to flow with no apparent damage to the sheet membrane. The membrane evaporator also serves to de-gas the water loop from entrained gases, thereby eliminating the need for special degassing equipment such as is needed by the current spacesuit system. As water flows through the three annular water channels, water evaporates with the vapor flowing across the hydrophobic, porous sheet membrane to the vacuum side of the membrane. The rate at which water evaporates, and therefore, the rate at which the flowing water is cooled, is a function of the difference between the water saturation pressure on the water side of the membrane, and the pressure on the vacuum side of the membrane. The primary theory is that the hydrophobic sheet membrane retains water, but permits vapor pass-through when the vapor side pressure is less than the water saturation pressure. This results in evaporative cooling of the remaining water.

  13. Synthetic Biological Membrane (SBM)

    Data.gov (United States)

    National Aeronautics and Space Administration — The ultimate goal of the Synthetic Biological Membrane project is to develop a new type of membrane that will enable the wastewater treatment system required on...

  14. Oxygen transport membrane

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof.......The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof....

  15. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T [Huntington Beach, CA; Sahimi, Muhammad [Altadena, CA; Fayyaz-Najafi, Babak [Richmond, CA; Harale, Aadesh [Los Angeles, CA; Park, Byoung-Gi [Yeosu, KR; Liu, Paul K. T. [Lafayette Hill, PA

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  16. Premature rupture of membranes

    Science.gov (United States)

    ... gov/ency/patientinstructions/000512.htm Premature rupture of membranes To use the sharing features on this page, ... water that surrounds your baby in the womb. Membranes or layers of tissue hold in this fluid. ...

  17. Transmembrane Signalling: Membrane messengers

    Science.gov (United States)

    Cockroft, Scott L.

    2017-05-01

    Life has evolved elaborate means of communicating essential chemical information across cell membranes. Inspired by biology, two new artificial mechanisms have now been developed that use synthetic messenger molecules to relay chemical signals into or across lipid membranes.

  18. Idiopathic epiretinal membrane

    NARCIS (Netherlands)

    Bu, Shao-Chong; Kuijer, Roelof; Li, Xiao-Rong; Hooymans, Johanna M M; Los, Leonoor I

    2014-01-01

    Background: Idiopathic epiretinal membrane (iERM) is a fibrocellular membrane that proliferates on the inner surface of the retina at the macular area. Membrane contraction is an important sight-threatening event and is due to fibrotic remodeling. Methods: Analysis of the current literature

  19. Model cell membranes

    DEFF Research Database (Denmark)

    Günther-Pomorski, Thomas; Nylander, Tommy; Cardenas Gomez, Marite

    2014-01-01

    The high complexity of biological membranes has motivated the development and application of a wide range of model membrane systems to study biochemical and biophysical aspects of membranes in situ under well defined conditions. The aim is to provide fundamental understanding of processes control...

  20. Membrane contactor applications

    NARCIS (Netherlands)

    Klaassen, R.; Feron, P.H.M.; Jansen, A.

    2008-01-01

    In a membrane contactor the membrane separation is completely integrated with an extraction or absorption operation in order to exploit the benefits of both technologies fully. Membrane contactor applications that have been developed can be found in both water and gas treatment. Several recently

  1. On "spinning" membrane models

    NARCIS (Netherlands)

    Bergshoeff, E.; Sezgin, E.; Townsend, P.K.

    1988-01-01

    Several alternative actions for a bosonic membrane have recently been proposed. We show that a linearly realized locally world-volume-supersymmetric (spinning membrane) extension of any of these actions implies an analogous extension of the standard Dirac membrane action. We further show that a

  2. Meniscus Membranes For Separation

    Science.gov (United States)

    Dye, Robert C.; Jorgensen, Betty; Pesiri, David R.

    2005-09-20

    Gas separation membranes, especially meniscus-shaped membranes for gas separations are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas separation is provided.

  3. Meniscus membranes for separations

    Science.gov (United States)

    Dye, Robert C [Irvine, CA; Jorgensen, Betty [Jemez Springs, NM; Pesiri, David R [Aliso Viejo, CA

    2004-01-27

    Gas separation membranes, especially meniscus-shaped membranes for gas separations are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas separation is provided.

  4. Plasma membrane ATPases

    DEFF Research Database (Denmark)

    Palmgren, Michael Broberg; Bækgaard, Lone; Lopez Marques, Rosa Laura

    2011-01-01

    membrane include ABC transporters, vacuolar (V-type) H+ pumps, and P-type pumps. These pumps all utilize ATP as a fuel for energizing pumping. This review focuses on the physiological roles of plasma membrane P-type pumps, as they represent the major ATP hydrolytic activity in this membrane....

  5. Microporous silica membranes

    DEFF Research Database (Denmark)

    Boffa, Vittorio; Yue, Yuanzheng

    2012-01-01

    Hydrothermal stability is a crucial factor for the application of microporous silica-based membranes in industrial processes. Indeed, it is well established that steam exposure may cause densification and defect formation in microporous silica membranes, which are detrimental to both membrane...... permeability and selectivity. Numerous previous studies show that microporous transition metal doped-silica membranes are hydrothermally more stable than pure silica membranes, but less permeable. Here we present a quantitative study on the impact of type and concentration of transition metal ions...... on the microporous structure, stability and permeability of amorphous silica-based membranes, providing information on how to design chemical compositions and synthetic paths for the fabrication of silica-based membranes with a well accessible and highly stabile microporous structure....

  6. Clustering on Membranes

    DEFF Research Database (Denmark)

    Johannes, Ludger; Pezeshkian, Weria; Ipsen, John H

    2018-01-01

    Clustering of extracellular ligands and proteins on the plasma membrane is required to perform specific cellular functions, such as signaling and endocytosis. Attractive forces that originate in perturbations of the membrane's physical properties contribute to this clustering, in addition to direct...... protein-protein interactions. However, these membrane-mediated forces have not all been equally considered, despite their importance. In this review, we describe how line tension, lipid depletion, and membrane curvature contribute to membrane-mediated clustering. Additional attractive forces that arise...... from protein-induced perturbation of a membrane's fluctuations are also described. This review aims to provide a survey of the current understanding of membrane-mediated clustering and how this supports precise biological functions....

  7. Application of dynamic membranes in anaerobic membranes in anaerobic membrane bioreactor systems

    NARCIS (Netherlands)

    Erşahin, M.E.

    2015-01-01

    Anaerobic membrane bioreactors (AnMBRs) physically ensure biomass retention by the application of a membrane filtration process. With growing application experiences from aerobic membrane bioreactors (MBRs), the combination of membrane and anaerobic processes has received much attention and become

  8. Early-Transition Output Decline Revisited

    Directory of Open Access Journals (Sweden)

    Crt Kostevc

    2016-05-01

    Full Text Available In this paper we revisit the issue of aggregate output decline that took place in the early transition period. We propose an alternative explanation of output decline that is applicable to Central- and Eastern-European countries. In the first part of the paper we develop a simple dynamic general equilibrium model that builds on work by Gomulka and Lane (2001. In particular, we consider price liberalization, interpreted as elimination of distortionary taxation, as a trigger of the output decline. We show that price liberalization in interaction with heterogeneous adjustment costs and non-employment benefits lead to aggregate output decline and surge in wage inequality. While these patterns are consistent with actual dynamics in CEE countries, this model cannot generate output decline in all sectors. Instead sectors that were initially taxed even exhibit output growth. Thus, in the second part we consider an alternative general equilibrium model with only one production sector and two types of labor and distortion in a form of wage compression during the socialist era. The trigger for labor mobility and consequently output decline is wage liberalization. Assuming heterogeneity of workers in terms of adjustment costs and non-employment benefits can explain output decline in all industries.

  9. Post-inflationary gravitino production revisited

    International Nuclear Information System (INIS)

    Ellis, John; Garcia, Marcos A.G.; Olive, Keith A.; Nanopoulos, Dimitri V.; Peloso, Marco

    2016-01-01

    We revisit gravitino production following inflation. As a first step, we review the standard calculation of gravitino production in the thermal plasma formed at the end of post-inflationary reheating when the inflaton has completely decayed. Next we consider gravitino production prior to the completion of reheating, assuming that the inflaton decay products thermalize instantaneously while they are still dilute. We then argue that instantaneous thermalization is in general a good approximation, and also show that the contribution of non-thermal gravitino production via the collisions of inflaton decay products prior to thermalization is relatively small. Our final estimate of the gravitino-to-entropy ratio is approximated well by a standard calculation of gravitino production in the post-inflationary thermal plasma assuming total instantaneous decay and thermalization at a time t ≅ 1.2/Γ φ . Finally, in light of our calculations, we consider potential implications of upper limits on the gravitino abundance for models of inflation, with particular attention to scenarios for inflaton decays in supersymmetric Starobinsky-like models

  10. Pair Production Constraints on Superluminal Neutrinos Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Stanley J.; /SLAC; Gardner, Susan; /Kentucky U.

    2012-02-16

    We revisit the pair creation constraint on superluminal neutrinos considered by Cohen and Glashow in order to clarify which types of superluminal models are constrained. We show that a model in which the superluminal neutrino is effectively light-like can evade the Cohen-Glashow constraint. In summary, any model for which the CG pair production process operates is excluded because such timelike neutrinos would not be detected by OPERA or other experiments. However, a superluminal neutrino which is effectively lightlike with fixed p{sup 2} can evade the Cohen-Glashow constraint because of energy-momentum conservation. The coincidence involved in explaining the SN1987A constraint certainly makes such a picture improbable - but it is still intrinsically possible. The lightlike model is appealing in that it does not violate Lorentz symmetry in particle interactions, although one would expect Hughes-Drever tests to turn up a violation eventually. Other evasions of the CG constraints are also possible; perhaps, e.g., the neutrino takes a 'short cut' through extra dimensions or suffers anomalous acceleration in matter. Irrespective of the OPERA result, Lorentz-violating interactions remain possible, and ongoing experimental investigation of such possibilities should continue.

  11. The Super-GUT CMSSM Revisited

    CERN Document Server

    Ellis, John

    2016-01-01

    We revisit minimal supersymmetric SU(5) grand unification (GUT) models in which the soft supersymmetry-breaking parameters of the minimal supersymmetric Standard Model (MSSM) are universal at some input scale, $M_{in}$, above the supersymmetric gauge coupling unification scale, $M_{GUT}$. As in the constrained MSSM (CMSSM), we assume that the scalar masses and gaugino masses have common values, $m_0$ and $m_{1/2}$ respectively, at $M_{in}$, as do the trilinear soft supersymmetry-breaking parameters $A_0$. Going beyond previous studies of such a super-GUT CMSSM scenario, we explore the constraints imposed by the lower limit on the proton lifetime and the LHC measurement of the Higgs mass, $m_h$. We find regions of $m_0$, $m_{1/2}$, $A_0$ and the parameters of the SU(5) superpotential that are compatible with these and other phenomenological constraints such as the density of cold dark matter, which we assume to be provided by the lightest neutralino. Typically, these allowed regions appear for $m_0$ and $m_{1/...

  12. Revisiting Hansen Solubility Parameters by Including Thermodynamics.

    Science.gov (United States)

    Louwerse, Manuel J; Maldonado, Ana; Rousseau, Simon; Moreau-Masselon, Chloe; Roux, Bernard; Rothenberg, Gadi

    2017-11-03

    The Hansen solubility parameter approach is revisited by implementing the thermodynamics of dissolution and mixing. Hansen's pragmatic approach has earned its spurs in predicting solvents for polymer solutions, but for molecular solutes improvements are needed. By going into the details of entropy and enthalpy, several corrections are suggested that make the methodology thermodynamically sound without losing its ease of use. The most important corrections include accounting for the solvent molecules' size, the destruction of the solid's crystal structure, and the specificity of hydrogen-bonding interactions, as well as opportunities to predict the solubility at extrapolated temperatures. Testing the original and the improved methods on a large industrial dataset including solvent blends, fit qualities improved from 0.89 to 0.97 and the percentage of correct predictions rose from 54 % to 78 %. Full Matlab scripts are included in the Supporting Information, allowing readers to implement these improvements on their own datasets. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Searle's"Dualism Revisited"

    Energy Technology Data Exchange (ETDEWEB)

    P., Henry

    2008-11-20

    A recent article in which John Searle claims to refute dualism is examined from a scientific perspective. John Searle begins his recent article 'Dualism Revisited' by stating his belief that the philosophical problem of consciousness has a scientific solution. He then claims to refute dualism. It is therefore appropriate to examine his arguments against dualism from a scientific perspective. Scientific physical theories contain two kinds of descriptions: (1) Descriptions of our empirical findings, expressed in an every-day language that allows us communicate to each other our sensory experiences pertaining to what we have done and what we have learned; and (2) Descriptions of a theoretical model, expressed in a mathematical language that allows us to communicate to each other certain ideas that exist in our mathematical imaginations, and that are believed to represent, within our streams of consciousness, certain aspects of reality that we deem to exist independently of their being perceived by any human observer. These two parts of our scientific description correspond to the two aspects of our general contemporary dualistic understanding of the total reality in which we are imbedded, namely the empirical-mental aspect and the theoretical-physical aspect. The duality question is whether this general dualistic understanding of ourselves should be regarded as false in some important philosophical or scientific sense.

  14. [What mirror neurons have revealed: revisited].

    Science.gov (United States)

    Murata, Akira; Maeda, Kazutaka

    2014-06-01

    The first paper on mirror neurons was published in 1992. In the span of over two decades since then, much knowledge about the relationship between social cognitive function and the motor control system has been accumulated. Direct matching of visual actions and their corresponding motor representations is the most important functional property of mirror neuron. Many studies have emphasized intrinsic simulation as a core concept for mirror neurons. Mirror neurons are thought to play a role in social cognitive function. However, the function of mirror neurons in the macaque remains unclear, because such cognitive functions are limited or lacking in macaque monkeys. It is therefore important to discuss these neurons in the context of motor function. Rizzolatti and colleagues have stressed that the most important function of mirror neurons in macaques is recognition of actions performed by other individuals. I suggest that mirror neurons in the Macaque inferior pariental lobule might be correlated with body schema. In the parieto-premotor network, matching of corollary discharge and actual sensory feedback is an essential neuronal operation. Recently, neurons showing mirror properties were found in some cortical areas outside the mirror neuron system. The current work would revisit the outcomes of mirror neuron studies to discuss the function of mirror neurons in the monkey.

  15. Structural sensitivity of biological models revisited.

    Science.gov (United States)

    Cordoleani, Flora; Flora, Cordoleani; Nerini, David; David, Nerini; Gauduchon, Mathias; Mathias, Gauduchon; Morozov, Andrew; Andrew, Morozov; Poggiale, Jean-Christophe; Jean-Christophe, Poggiale

    2011-08-21

    Enhancing the predictive power of models in biology is a challenging issue. Among the major difficulties impeding model development and implementation are the sensitivity of outcomes to variations in model parameters, the problem of choosing of particular expressions for the parametrization of functional relations, and difficulties in validating models using laboratory data and/or field observations. In this paper, we revisit the phenomenon which is referred to as structural sensitivity of a model. Structural sensitivity arises as a result of the interplay between sensitivity of model outcomes to variations in parameters and sensitivity to the choice of model functions, and this can be somewhat of a bottleneck in improving the models predictive power. We provide a rigorous definition of structural sensitivity and we show how we can quantify the degree of sensitivity of a model based on the Hausdorff distance concept. We propose a simple semi-analytical test of structural sensitivity in an ODE modeling framework. Furthermore, we emphasize the importance of directly linking the variability of field/experimental data and model predictions, and we demonstrate a way of assessing the robustness of modeling predictions with respect to data sampling variability. As an insightful illustrative example, we test our sensitivity analysis methods on a chemostat predator-prey model, where we use laboratory data on the feeding of protozoa to parameterize the predator functional response. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Pipe failure probability - the Thomas paper revisited

    International Nuclear Information System (INIS)

    Lydell, B.O.Y.

    2000-01-01

    Almost twenty years ago, in Volume 2 of Reliability Engineering (the predecessor of Reliability Engineering and System Safety), a paper by H. M. Thomas of Rolls Royce and Associates Ltd. presented a generalized approach to the estimation of piping and vessel failure probability. The 'Thomas-approach' used insights from actual failure statistics to calculate the probability of leakage and conditional probability of rupture given leakage. It was intended for practitioners without access to data on the service experience with piping and piping system components. This article revisits the Thomas paper by drawing on insights from development of a new database on piping failures in commercial nuclear power plants worldwide (SKI-PIPE). Partially sponsored by the Swedish Nuclear Power Inspectorate (SKI), the R and D leading up to this note was performed during 1994-1999. Motivated by data requirements of reliability analysis and probabilistic safety assessment (PSA), the new database supports statistical analysis of piping failure data. Against the background of this database development program, the article reviews the applicability of the 'Thomas approach' in applied risk and reliability analysis. It addresses the question whether a new and expanded database on the service experience with piping systems would alter the original piping reliability correlation as suggested by H. M. Thomas

  17. Revisiting the survival mnemonic effect in children.

    Science.gov (United States)

    Pand eirada, Josefa N S; Pires, Luísa; Soares, Sandra C

    2014-04-29

    The survival processing paradigm is designed to explore the adaptive nature of memory functioning. The mnemonic advantage of processing information in fitness-relevant contexts, as has been demonstrated using this paradigm, is now well established, particularly in young adults; this phenomenon is often referred to as the "survival processing effect." In the current experiment, we revisited the investigation of this effect in children and tested it in a new cultural group, using a procedure that differs from the existing studies with children. A group of 40 Portuguese children rated the relevance of unrelated words to a survival and a new moving scenario. This encoding task was followed by a surprise free-recall task. Akin to what is typically found, survival processing produced better memory performance than the control condition (moving). These data put on firmer ground the idea that a mnemonic tuning to fitness-relevant encodings is present early in development. The theoretical importance of this result to the adaptive memory literature is discussed, as well as potential practical implications of this kind of approach to the study of memory in children.

  18. Revisiting the Survival Mnemonic Effect in Children

    Directory of Open Access Journals (Sweden)

    Josefa N. S. Pand Eirada

    2014-04-01

    Full Text Available The survival processing paradigm is designed to explore the adaptive nature of memory functioning. The mnemonic advantage of processing information in fitness-relevant contexts, as has been demonstrated using this paradigm, is now well established, particularly in young adults; this phenomenon is often referred to as the “survival processing effect.” In the current experiment, we revisited the investigation of this effect in children and tested it in a new cultural group, using a procedure that differs from the existing studies with children. A group of 40 Portuguese children rated the relevance of unrelated words to a survival and a new moving scenario. This encoding task was followed by a surprise free-recall task. Akin to what is typically found, survival processing produced better memory performance than the control condition (moving. These data put on firmer ground the idea that a mnemonic tuning to fitness-relevant encodings is present early in development. The theoretical importance of this result to the adaptive memory literature is discussed, as well as potential practical implications of this kind of approach to the study of memory in children.

  19. Pair Production Constraints on Superluminal Neutrinos Revisited

    International Nuclear Information System (INIS)

    Brodsky, Stanley

    2012-01-01

    We revisit the pair creation constraint on superluminal neutrinos considered by Cohen and Glashow in order to clarify which types of superluminal models are constrained. We show that a model in which the superluminal neutrino is effectively light-like can evade the Cohen-Glashow constraint. In summary, any model for which the CG pair production process operates is excluded because such timelike neutrinos would not be detected by OPERA or other experiments. However, a superluminal neutrino which is effectively lightlike with fixed p 2 can evade the Cohen-Glashow constraint because of energy-momentum conservation. The coincidence involved in explaining the SN1987A constraint certainly makes such a picture improbable - but it is still intrinsically possible. The lightlike model is appealing in that it does not violate Lorentz symmetry in particle interactions, although one would expect Hughes-Drever tests to turn up a violation eventually. Other evasions of the CG constraints are also possible; perhaps, e.g., the neutrino takes a 'short cut' through extra dimensions or suffers anomalous acceleration in matter. Irrespective of the OPERA result, Lorentz-violating interactions remain possible, and ongoing experimental investigation of such possibilities should continue.

  20. Titmuss and the gift relationship: altruism revisited.

    Science.gov (United States)

    Rapport, F L; Maggs, C J

    2002-12-01

    This paper revisits Richard Titmuss' 1970s blood donation model in the light of its 1997 reprint in order to consider whether we are justified in continuing to accept that the main reason for blood donation (and other donation types) is an altruistic desire to help others. This paper explores how others have examined the notion of altruism, before concentrating on two major elements of Titmuss' work: blood donors' motives to donate and the social implications of gift-giving in relation to the uniqueness of blood donation. Donor motivation is discussed in detail with particular reference to questions 4 and 5 of Titmuss' blood donor survey and through a critical appraisal approach to his work. Methodological inconsistencies are revealed in the design and implementation of the survey, as well as in Titmuss' list of blood donation's unique attributes, bringing into question the rigour of his findings. It may be that blood donors are altruistically motivated, but such conclusions cannot be drawn from this work. It is also unclear if 'altruism' can be shown in the example of blood donation or other donation types. We should reconsider the motivation behind gifting in health care in the light of these findings and ensure that evidence-based practice is consistent with methodological rigour. Nurses and other health professionals need to have a clearer understanding of concepts such as altruism in order to appreciate why people seek to donate.

  1. Hyperinflation in Brazil, Israel, and Nicaragua revisited

    Science.gov (United States)

    Szybisz, Martín A.; Szybisz, Leszek

    2017-01-01

    The aim of the present work is to address the description of hyperinflation regimens in economy. The spirals of hyperinflation developed in Brazil, Israel, and Nicaragua are revisited. This new analysis of data indicates that the episodes occurred in Brazil and Nicaragua can be understood within the frame of the model available in the literature, which is based on a nonlinear feedback (NLF) characterized by an exponent β > 0. In the NLF model the accumulated consumer price index carries a finite time singularity of the type 1 /(tc - t) (1 - β) / β determining a critical time tc at which the economy would crash. It is shown that in the case of Brazil the entire episode cannot be described with a unique set of parameters because the time series was strongly affected by a change of policy. This fact gives support to the ;so called; Lucas critique, who stated that model's parameters usually change once policy changes. On the other hand, such a model is not able to provide any tc in the case of the weaker hyperinflation occurred in Israel. It is shown that in this case the fit of data yields β → 0. This limit leads to the linear feedback formulation which does not predict any tc. An extension for the NLF model is suggested.

  2. Carbon emission from global hydroelectric reservoirs revisited.

    Science.gov (United States)

    Li, Siyue; Zhang, Quanfa

    2014-12-01

    Substantial greenhouse gas (GHG) emissions from hydropower reservoirs have been of great concerns recently, yet the significant carbon emitters of drawdown area and reservoir downstream (including spillways and turbines as well as river reaches below dams) have not been included in global carbon budget. Here, we revisit GHG emission from hydropower reservoirs by considering reservoir surface area, drawdown zone and reservoir downstream. Our estimates demonstrate around 301.3 Tg carbon dioxide (CO2)/year and 18.7 Tg methane (CH4)/year from global hydroelectric reservoirs, which are much higher than recent observations. The sum of drawdown and downstream emission, which is generally overlooked, represents 42 % CO2 and 67 % CH4 of the total emissions from hydropower reservoirs. Accordingly, the global average emissions from hydropower are estimated to be 92 g CO2/kWh and 5.7 g CH4/kWh. Nonetheless, global hydroelectricity could currently reduce approximate 2,351 Tg CO2eq/year with respect to fuel fossil plant alternative. The new findings show a substantial revision of carbon emission from the global hydropower reservoirs.

  3. Computational Electrocardiography: Revisiting Holter ECG Monitoring.

    Science.gov (United States)

    Deserno, Thomas M; Marx, Nikolaus

    2016-08-05

    Since 1942, when Goldberger introduced the 12-lead electrocardiography (ECG), this diagnostic method has not been changed. After 70 years of technologic developments, we revisit Holter ECG from recording to understanding. A fundamental change is fore-seen towards "computational ECG" (CECG), where continuous monitoring is producing big data volumes that are impossible to be inspected conventionally but require efficient computational methods. We draw parallels between CECG and computational biology, in particular with respect to computed tomography, computed radiology, and computed photography. From that, we identify technology and methodology needed for CECG. Real-time transfer of raw data into meaningful parameters that are tracked over time will allow prediction of serious events, such as sudden cardiac death. Evolved from Holter's technology, portable smartphones with Bluetooth-connected textile-embedded sensors will capture noisy raw data (recording), process meaningful parameters over time (analysis), and transfer them to cloud services for sharing (handling), predicting serious events, and alarming (understanding). To make this happen, the following fields need more research: i) signal processing, ii) cycle decomposition; iii) cycle normalization, iv) cycle modeling, v) clinical parameter computation, vi) physiological modeling, and vii) event prediction. We shall start immediately developing methodology for CECG analysis and understanding.

  4. Revisiting CMB constraints on warm inflation

    Science.gov (United States)

    Arya, Richa; Dasgupta, Arnab; Goswami, Gaurav; Prasad, Jayanti; Rangarajan, Raghavan

    2018-02-01

    We revisit the constraints that Planck 2015 temperature, polarization and lensing data impose on the parameters of warm inflation. To this end, we study warm inflation driven by a single scalar field with a quartic self interaction potential in the weak dissipative regime. We analyse the effect of the parameters of warm inflation, namely, the inflaton self coupling λ and the inflaton dissipation parameter QP on the CMB angular power spectrum. We constrain λ and QP for 50 and 60 number of e-foldings with the full Planck 2015 data (TT, TE, EE + lowP and lensing) by performing a Markov-Chain Monte Carlo analysis using the publicly available code CosmoMC and obtain the joint as well as marginalized distributions of those parameters. We present our results in the form of mean and 68 % confidence limits on the parameters and also highlight the degeneracy between λ and QP in our analysis. From this analysis we show how warm inflation parameters can be well constrained using the Planck 2015 data.

  5. Revisiting Stephan's Quintet with deep optical images

    Science.gov (United States)

    Duc, Pierre-Alain; Cuillandre, Jean-Charles; Renaud, Florent

    2018-03-01

    Stephan's Quintet, a compact group of galaxies, is often used as a laboratory to study a number of phenomena, including physical processes in the interstellar medium, star formation, galaxy evolution, and the formation of fossil groups. As such, it has been subject to intensive multiwavelength observation campaigns. Yet, models lack constrains to pin down the role of each galaxy in the assembly of the group. We revisit here this system with multiband deep optical images obtained with MegaCam on the Canada-France-Hawaii Telescope (CFHT), focusing on the detection of low surface brightness (LSB) structures. They reveal a number of extended LSB features, some new, and some already visible in published images but not discussed before. An extended diffuse, reddish, lopsided, halo is detected towards the early-type galaxy NGC 7317, the role of which had so far been ignored in models. The presence of this halo made of old stars may indicate that the group formed earlier than previously thought. Finally, a number of additional diffuse filaments are visible, some close to the foreground galaxy NGC 7331 located in the same field. Their structure and association with mid-infrared emission suggest contamination by emission from Galactic cirrus.

  6. Revisit to diffraction anomalous fine structure

    International Nuclear Information System (INIS)

    Kawaguchi, T.; Fukuda, K.; Tokuda, K.; Shimada, K.; Ichitsubo, T.; Oishi, M.; Mizuki, J.; Matsubara, E.

    2014-01-01

    The diffraction anomalous fine structure method has been revisited by applying this measurement technique to polycrystalline samples and using an analytical method with the logarithmic dispersion relation. The diffraction anomalous fine structure (DAFS) method that is a spectroscopic analysis combined with resonant X-ray diffraction enables the determination of the valence state and local structure of a selected element at a specific crystalline site and/or phase. This method has been improved by using a polycrystalline sample, channel-cut monochromator optics with an undulator synchrotron radiation source, an area detector and direct determination of resonant terms with a logarithmic dispersion relation. This study makes the DAFS method more convenient and saves a large amount of measurement time in comparison with the conventional DAFS method with a single crystal. The improved DAFS method has been applied to some model samples, Ni foil and Fe 3 O 4 powder, to demonstrate the validity of the measurement and the analysis of the present DAFS method

  7. Supported ionic liquid membrane in membrane reactor

    Science.gov (United States)

    Makertihartha, I. G. B. N.; Zunita, M.; Dharmawijaya, P. T.; Wenten, I. G.

    2017-01-01

    Membrane reactor is a device that integrates membrane based separation and (catalytic) chemical reaction vessel in a single device. Ionic liquids, considered to be a relatively recent magical chemical due to their unique properties, have a large variety of applications in all areas of chemical industries. Moreover, the ionic liquid can be used as membrane separation layer and/or catalytically active site. This paper will review utilization of ionic liquid in membrane reactor related applications especially Fischer-Tropsch, hydrogenation, and dehydrogenation reaction. This paper also reviews about the capability of ionic liquid in equilibrium reaction that produces CO2 product so that the reaction will move towards the product. Water gas shift reaction in ammonia production also direct Dimethyl Ether (DME) synthesis that produces CO2 product will be discussed. Based on a review of numerous articles on supported ionic liquid membrane (SILM) indicate that ionic liquids have the potential to support the process of chemical reaction and separation in a membrane reactor.

  8. Emulsification using microporous membranes

    Directory of Open Access Journals (Sweden)

    Goran T. Vladisavljević

    2011-10-01

    Full Text Available Membrane emulsification is a process of injecting a pure dispersed phase or pre-emulsion through a microporous membrane into the continuous phase. As a result of the immiscibility of the two phases, droplets of the dispersed phase are formed at the outlets of membrane pores. The droplets formed in the process are removed from the membrane surface by applying cross-flow or stirring of the continuous phase or using a dynamic (rotating or vibrating membrane. The most commonly used membrane for emulsification is the Shirasu Porous Glass (SPG membrane, fabricated through spinodal decomposition in a melt consisting of Japanese volcanic ash (Shirasu, boric acid and calcium carbonate. Microsieve membranes are increasingly popular as an alternative to highly tortuous glass and ceramic membranes. Microsieves are usually fabricated from nickel by photolithography and electroplating or they can be manufactured from silicon nitride via Reactive Ion Etching (RIE. An advantage of microsieves compared to the SPG membrane is in much higher transmembrane fluxes and higher tolerance to fouling by the emulsion ingredients due to the existence of short, straight through pores. Unlike conventional emulsification devices such as high-pressure valve homogenisers and rotor-stator devices, membrane emulsification devices permit a precise control over the mean pore size over a wide range and during the process insignificant amount of energy is dissipated as heat. The drop size is primarily determined by the pore size, but it depends also on other parameters, such as membrane wettability, emulsion formulation, shear stress on the membrane surface, transmembrane pressure, etc.

  9. Educational Administration and the Management of Knowledge: 1980 Revisited

    Science.gov (United States)

    Bates, Richard

    2013-01-01

    This paper revisits the thesis of a 1980 paper that suggested a new approach to educational administration based upon the New Sociology of Education. In particular it updates answers to the six key questions asked by that paper: what counts as knowledge; how is what counts as knowledge organised; how is what counts as knowledge transmitted; how is…

  10. Assesment of mucoadhesion using small deformation rheology revisited

    DEFF Research Database (Denmark)

    Harloff-Helleberg, Stine; Vissing, Karina Juul; Nielsen, Hanne Mørck

    2017-01-01

    This work revisits the commonly used approach to assess mucoadhesion in drug delivery by small deformation rheology. The results show that biosimilar mucus serves as a more predictive mucus model system when compared to mucin suspensions. Data is fitted including error propagation, different from...

  11. Alban Berg's Wozzeck : Revisiting a Historically Sedimented Metaphor

    African Journals Online (AJOL)

    Alban Berg's Wozzeck: Revisiting a Historically Sedimented Metaphor. Bertha Spies. Abstract. The binary opposition between music text and reader can be transformed into a dialogue when the text is allowed to "speak back". A dialogue approach helps to provide an answer to the question of two different interpretations of ...

  12. Revisiting the Role of Communication in Adolescent Intimate Partner Violence

    Science.gov (United States)

    Messinger, Adam M.; Rickert, Vaughn I.; Fry, Deborah A.; Lessel, Harriet; Davidson, Leslie L.

    2012-01-01

    A growing literature suggests that communication strategies can promote or inhibit intimate partner violence (IPV). Research on communication is still needed on a group ripe for early IPV intervention: high school-aged adolescents. This article revisits our previous analyses of young female reproductive clinic patients (Messinger, Davidson, &…

  13. Antidote for Zero Tolerance: Revisiting a "Reclaiming" School.

    Science.gov (United States)

    Farner, Conrad D.

    2002-01-01

    Reports on a revisit to the Frank Lloyd Wright Middle School, which implemented strategies to deal with disciplinary problems. The school continues to progress towards creating the type of reclaiming environment necessary to ensure the needs of all students. Strategies used include alternatives to zero tolerance policy; smaller teams of students;…

  14. Jesus and the law revisited | Loader | HTS Teologiese Studies ...

    African Journals Online (AJOL)

    This article revisited the issue of Jesus' attitude towards the Torah on the basis of a critical discussion of the most recent extensive treatment of the theme by Meier in his A marginal Jew: Rethinking the historical Jesus: Volume four: Law and love (2009). It engaged Meier's contribution in the light of contemporary research, ...

  15. A different kind of reformation : Revisiting the Lynn White Thesis

    NARCIS (Netherlands)

    Jedan, Christoph

    2017-01-01

    This commentary revisits Lynn White’s article, ‘The Historical Roots of Our Ecologic Crisis’ (1967), and questions the assumption that there is a unified ‘Lynn White thesis’. Instead, it proposes a complex narrative in which four key elements can be identified: (1) the long history of human impact

  16. Revisiting Jack Goody to Rethink Determinisms in Literacy Studies

    Science.gov (United States)

    Collin, Ross

    2013-01-01

    This article revisits Goody's arguments about literacy's influence on social arrangements, culture, cognition, economics, and other domains of existence. Whereas some of his arguments tend toward technological determinism (i.e., literacy causes change in the world), other of his arguments construe literacy as a force that shapes and is shaped by…

  17. A Feminist Revisit to the First-Year Curriculum.

    Science.gov (United States)

    Bernstein, Anita

    1996-01-01

    A seminar at Chicago-Kent College of Law (Illinois) that reviews six first-year law school courses by focusing on feminist issues in course content and structure is described. The seminar functions as both a review and a shift in perspective. Courses revisited include civil procedure, contracts, criminal law, justice and the legal system,…

  18. The military glider revisited | Heitman | Scientia Militaria: South ...

    African Journals Online (AJOL)

    Scientia Militaria: South African Journal of Military Studies. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 12, No 3 (1982) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. The military glider revisited.

  19. Rereading Albert B. Lord's The Singer of Tales . Revisiting the ...

    African Journals Online (AJOL)

    Access to a fresh set of video-recordings of Sesotho praise-poetry made in the year 2000 enabled the author to revisit his adaptation of Albert Lord's definition of the formula as a dynamic compositional device that the oral poet utilizes during delivery. The basic adaptation made in 1983 pertains to heroic praises (dithoko tsa ...

  20. Facilitating Grade Acceleration: Revisiting the Wisdom of John Feldhusen

    Science.gov (United States)

    Culross, Rita R.; Jolly, Jennifer L.; Winkler, Daniel

    2013-01-01

    This article revisits the 1986 Feldhusen, Proctor, and Black recommendations on grade skipping. These recommendations originally appeared as 12 guidelines. In this article, the guidelines are grouped into three general categories: how to screen accelerant candidates, how to engage with the adults in the acceleration process (e.g., teachers,…

  1. Environmental Education and Politics: Snakes and Ladders Revisited

    Science.gov (United States)

    Chapman, David

    2004-01-01

    This paper revisits the history of environmental education in Australia in the 1970s and 1980s and draws parallels between these and current events in four countries, including Australia. It is argued that little has changed and that few environmental educators confront the inherently political nature of their work. It is concluded that…

  2. Revisiting Mental Simulation in Language Comprehension: Six Replication Attempts

    NARCIS (Netherlands)

    R.A. Zwaan (Rolf); D. Pecher (Diane)

    2012-01-01

    textabstractThe notion of language comprehension as mental simulation has become popular in cognitive science. We revisit some of the original empirical evidence for this. Specifically, we attempted to replicate the findings from earlier studies that examined the mental simulation of object

  3. Primary maternal preoccupation revisited: circuits, genes, and the ...

    African Journals Online (AJOL)

    QuickSilver

    2003-05-08

    May 8, 2003 ... Primary maternal preoccupation revisited: circuits, genes, and the crucial role of early ... If similar mechanisms are at work in human populations, they may provide a basis for successful early ... develops toward the end of pregnancy and lasts for the first few post- natal weeks, he likened it to a withdrawn or ...

  4. Resettlement Revisited: The Post-Resettlement Assessment in Biftu ...

    African Journals Online (AJOL)

    user

    Resettlement Revisited: The Post-Resettlement Assessment in Biftu Jalala. Resettlement Site .... assessment is done based on the field work held in 2009. 2.2. An overview of the Ethiopian experience of resettlement .... attain food security by the end of the year 2006. So far over 123,000 households have been voluntarily ...

  5. Revisiting the Utility of Industrial Sociology in National Development ...

    African Journals Online (AJOL)

    Toshiba

    thus need to be revisited from time to time in the light of emerging contemporary issues. Against this ... services which achieve the ends of the state – security, welfare and the pursuit of national interests in the global ..... and leadership being experienced in many work organisations have made them unable to achieve their ...

  6. The residence time of water in the atmosphere revisited

    NARCIS (Netherlands)

    Van Der Ent, Ruud J.; Tuinenburg, Obbe A.

    2017-01-01

    This paper revisits the knowledge on the residence time of water in the atmosphere. Based on state-of-the-art data of the hydrological cycle we derive a global average residence time of 8.9 ± 0.4 days (uncertainty given as 1 standard deviation). We use two different atmospheric moisture tracking

  7. Language Transmission Revisited: Family Type, Linguistic Environment and Language Attitudes

    Science.gov (United States)

    Schupbach, Doris

    2009-01-01

    This article revisits factors in intergenerational language maintenance and shift within the family. It does so through an in-depth analysis of what 14 migrants to Australia from German-speaking Switzerland reported in written life stories and subsequent life story interviews. The participants represent four family types and a wide age range, and…

  8. The Importance of Being a Complement: CED Effects Revisited

    Science.gov (United States)

    Jurka, Johannes

    2010-01-01

    This dissertation revisits subject island effects (Ross 1967, Chomsky 1973) cross-linguistically. Controlled acceptability judgment studies in German, English, Japanese and Serbian show that extraction out of specifiers is consistently degraded compared to extraction out of complements, indicating that the Condition on Extraction domains (CED,…

  9. Revisiting the Continua of Biliteracy: International and Critical Perspectives.

    Science.gov (United States)

    Hornberger, Nancy H.; Skilton-Sylvester, Ellen

    2000-01-01

    The continua model of biliteracy offers a framework to situate research, teaching, and language planning in linguistically diverse settings. The continua model is revisited from the perspective of international cases of educational policy and practice in linguistically diverse settings, and from a critical perspective that seeks to make explicit…

  10. Lemba origins revisited: Tracing the ancestry of Y chromosomes in ...

    African Journals Online (AJOL)

    Background. Previous historical, anthropological and genetic data provided overwhelming support for the Semitic origins of the Lemba, a Bantu-speaking people in southern Africa. Objective. To revisit the question concerning genetic affinities between the Lemba and Jews. Methods. Y-chromosome variation was examined ...

  11. Faraday effect revisited: sum rules and convergence issues

    DEFF Research Database (Denmark)

    Cornean, Horia; Nenciu, Gheorghe

    2010-01-01

    This is the third paper of a series revisiting the Faraday effect. The question of the absolute convergence of the sums over the band indices entering the Verdet constant is considered. In general, sum rules and traces per unit volume play an important role in solid-state physics, and they give...

  12. Revisiting Constructivist Teaching Methods in Ontario Colleges Preparing for Accreditation

    Science.gov (United States)

    Schultz, Rachel A.

    2015-01-01

    At the time of writing, the first community colleges in Ontario were preparing for transition to an accreditation model from an audit system. This paper revisits constructivist literature, arguing that a more pragmatic definition of constructivism effectively blends positivist and interactionist philosophies to achieve both student centred…

  13. Revisiting deforestation in Africa (1990–2010): One more lost ...

    African Journals Online (AJOL)

    This spotlight revisits the dynamics and prognosis outlined in the late 1980's published in Déforestation en Afrique. This book on deforestation in Africa utilized available statistical data from the 1980's and was a pioneering self - styled attempt to provide a holistic viewpoint of the ongoing trends pertaining to deforestation in ...

  14. A control center design revisited: learning from users’ appropriation

    DEFF Research Database (Denmark)

    Souza da Conceição, Carolina; Cordeiro, Cláudia

    2014-01-01

    This paper aims to present the lessons learned during a control center design project by revisiting another control center from the same company designed two and a half years before by the same project team. In light of the experience with the first project and its analysis, the designers and res...

  15. Thorbecke Revisited : The Role of Doctrinaire Liberalism in Dutch Politics

    NARCIS (Netherlands)

    Drentje, Jan

    2011-01-01

    Thorbecke Revisited: The Role of Doctrinaire Liberalism in Dutch Politics In the political history of the nineteenth century Thorbecke played a crucial role. As the architect of the 1848 liberal constitutional reform he led three cabinets. In many ways he dominated the political discourse during the

  16. Ion-conducting membranes

    Energy Technology Data Exchange (ETDEWEB)

    Masel, Richard I.; Sajjad, Syed Dawar; Gao, Yan; Liu, Zengcai; Chen, Qingmei

    2017-12-26

    An anion-conducting polymeric membrane comprises a terpolymer of styrene, vinylbenzyl-R.sub.s and vinylbenzyl-R.sub.x. R.sub.s is a positively charged cyclic amine group. R.sub.x is at least one constituent selected from the group consisting Cl, OH and a reaction product between an OH or Cl and a species other than a simple amine or a cyclic amine. The total weight of the vinylbenzyl-R.sub.x groups is greater than 0.3% of the total weight of the membrane. In a preferred embodiment, the membrane is a Helper Membrane that increases the faradaic efficiency of an electrochemical cell into which the membrane is incorporated, and also allows product formation at lower voltages than in cells without the Helper Membrane.

  17. Gas separation with membranes

    International Nuclear Information System (INIS)

    Schulz, G.; Michele, H.; Werner, U.

    1982-01-01

    Gas separation with membranes has already been tested in numerous fields of application, e.g. uranium enrichment of H 2 separation. In many of these processes the mass transfer units, so-called permeators, have to be connected in tandem in order to achieve high concentrations. A most economical operating method provides for each case an optimization of the cascades with regard to the membrane materials, construction and design of module. By utilization of the concentration gradient along the membrane a new process development has been accomplished - the continuously operating membrane rectification unit. Investment and operating costs can be reduced considerably for a number of separating processes by combining a membrane rectification unit with a conventional recycling cascade. However, the new procedure requires that the specifications for the module construction, flow design, and membrane properties be reconsidered. (orig.) [de

  18. Chelating polymeric membranes

    KAUST Repository

    Peinemann, Klaus-Viktor

    2015-01-22

    The present application offers a solution to the current problems associated with recovery and recycling of precious metals from scrap material, discard articles, and other items comprising one or more precious metals. The solution is premised on a microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

  19. Polyarylether composition and membrane

    Science.gov (United States)

    Hung, Joyce; Brunelle, Daniel Joseph; Harmon, Marianne Elisabeth; Moore, David Roger; Stone, Joshua James; Zhou, Hongyi; Suriano, Joseph Anthony

    2010-11-09

    A composition including a polyarylether copolymer is provided. The copolymer includes a polyarylether backbone; and a sulfonated oligomeric group bonded to the polyarylether suitable for use as a cation conducting membrane. Method of bonding a sulfonated oligomeric group to the polyarylether backbone to form a polyarylether copolymer. The membrane may be formed from the polyarylether copolymer composition. The chain length of the sulfonated oligomeric group may be controlled to affect or control the ion conductivity of the membrane.

  20. A Structural Equation Model of Risk Perception of Rockfall for Revisit Intention

    OpenAIRE

    Ya-Fen Lee; Yun-Yao Chi

    2014-01-01

    The study aims to explore the relationship between risk perception of rockfall and revisit intention using a Structural Equation Modeling (SEM) analysis. A total of 573 valid questionnaires are collected from travelers to Taroko National Park, Taiwan. The findings show the majority of travelers have the medium perception of rockfall risk, and are willing to revisit the Taroko National Park. The revisit intention to Taroko National Park is influenced by hazardous preferences, willingness-to-pa...

  1. Photoresponsive nanostructured membranes

    KAUST Repository

    Madhavan, Poornima

    2016-07-26

    The perspective of adding stimuli-response to isoporous membranes stimulates the development of separation devices with pores, which would open or close under control of environment chemical composition, temperature or exposure to light. Changes in pH and temperature have been previously investigated. In this work, we demonstrate for the first time the preparation of photoresponsive isoporous membranes, applying self-assembly non-solvent induced phase separation to a new light responsive block copolymer. First, we optimized the membrane formation by using poly(styrene-b-anthracene methyl methacrylate-b-methylmethacrylate) (PS-b-PAnMMA-b-PMMA) copolymer, identifying the most suitable solvent, copolymer block length, and other parameters. The obtained final triblock copolymer membrane morphologies were characterized using atomic force and electron microscopy. The microscopic analysis reveals that the PS-b-PAnMMA-b-PMMA copolymer can form both lamellar and ordered hexagonal nanoporous structures on the membrane top layer in appropriate solvent compositions. The nanostructured membrane emits fluorescence due to the presence of the anthracene mid-block. On irradiation of light the PS-b-PAnMMA-b-PMMA copolymer membranes has an additional stimuli response. The anthracene group undergoes conformational changes by forming [4 + 4] cycloadducts and this alters the membrane\\'s water flux and solute retention. © 2016 The Royal Society of Chemistry.

  2. Gas separation membranes

    Science.gov (United States)

    Schell, William J.

    1979-01-01

    A dry, fabric supported, polymeric gas separation membrane, such as cellulose acetate, is prepared by casting a solution of the polymer onto a shrinkable fabric preferably formed of synthetic polymers such as polyester or polyamide filaments before washing, stretching or calendering (so called griege goods). The supported membrane is then subjected to gelling, annealing, and drying by solvent exchange. During the processing steps, both the fabric support and the membrane shrink a preselected, controlled amount which prevents curling, wrinkling or cracking of the membrane in flat form or when spirally wound into a gas separation element.

  3. Highway 61 Revisited: Bob Dilan i francuski poststrukturalizam / Highway 61 Revisited: Bob Dilan and French Poststructuralism

    Directory of Open Access Journals (Sweden)

    Nikola Dedić

    2013-06-01

    Full Text Available The main aim of this text is to show parallels between rock music and poststructuralist philosophy. As a case study one of the most celebrated rock albums of all times – Bob Dylan’s Highway 61 Revisited from 1965 is taken. It is one of the crucial albums in the history of popular culture which influenced further development of rock music within American counter culture of the 60s. Dylan’s turn from the politics of American New Left and folk movement, his relation towards the notions of the author and intertextuality, and his connection with experimental usage of language in the manner of avant-garde and neoavant-garde poetry, are juxtaposed with the main philosophical standpoints of Jean-François Lyotard, Jean Baudrillard, Roland Barthes and Julia Kristeva which historically and chronologically coincide with the appearance of Dylan’s album.

  4. Solar system anomalies: Revisiting Hubble's law

    Science.gov (United States)

    Plamondon, R.

    2017-12-01

    This paper investigates the impact of a new metric recently published [R. Plamondon and C. Ouellet-Plamondon, in On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics, and Relativistic Field Theories, edited by K. Rosquist, R. T. Jantzen, and R. Ruffini (World Scientific, Singapore, 2015), p. 1301] for studying the space-time geometry of a static symmetric massive object. This metric depends on a complementary error function (erfc) potential that characterizes the emergent gravitation field predicted by the model. This results in two types of deviations as compared to computations made on the basis of a Newtonian potential: a constant and a radial outcome. One key feature of the metric is that it postulates the existence of an intrinsic physical constant σ , the massive object-specific proper length that scales measurements in its surroundings. Although σ must be evaluated experimentally, we use a heuristic to estimate its value and point out some latent relationships between the Hubble constant, the secular increase in the astronomical unit, and the Pioneers delay. Indeed, highlighting the systematic errors that emerge when the effect of σ is neglected, one can link the Hubble constant H 0 to σ Sun and the secular increase V AU to σ Earth . The accuracy of the resulting numerical predictions, H 0 = 74 . 42 ( 0 . 02 ) ( km / s ) / Mpc and V AU ≅ 7.8 cm yr-1 , calls for more investigations of this new metric by specific experts. Moreover, we investigate the expected impacts of the new metric on the flyby anomalies, and we revisit the Pioneers delay. It is shown that both phenomena could be partly taken into account within the context of this unifying paradigm, with quite accurate numerical predictions. A correction for the osculating asymptotic velocity at the perigee of the order of 10 mm/s and an inward radial acceleration of 8 . 34 × 10 - 10 m / s 2 affecting the Pioneer ! space crafts could be explained by this new model.

  5. Double neutron stars: merger rates revisited

    Science.gov (United States)

    Chruslinska, Martyna; Belczynski, Krzysztof; Klencki, Jakub; Benacquista, Matthew

    2018-03-01

    We revisit double neutron star (DNS) formation in the classical binary evolution scenario in light of the recent Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo DNS detection (GW170817). The observationally estimated Galactic DNS merger rate of R_MW = 21^{+28}_{-14} Myr-1, based on three Galactic DNS systems, fully supports our standard input physics model with RMW = 24 Myr-1. This estimate for the Galaxy translates in a non-trivial way (due to cosmological evolution of progenitor stars in chemically evolving Universe) into a local (z ≈ 0) DNS merger rate density of Rlocal = 48 Gpc-3 yr-1, which is not consistent with the current LIGO/Virgo DNS merger rate estimate (1540^{+3200}_{-1220} Gpc-3 yr-1). Within our study of the parameter space, we find solutions that allow for DNS merger rates as high as R_local ≈ 600^{+600}_{-300} Gpc-3 yr-1 which are thus consistent with the LIGO/Virgo estimate. However, our corresponding BH-BH merger rates for the models with high DNS merger rates exceed the current LIGO/Virgo estimate of local BH-BH merger rate (12-213 Gpc-3 yr-1). Apart from being particularly sensitive to the common envelope treatment, DNS merger rates are rather robust against variations of several of the key factors probed in our study (e.g. mass transfer, angular momentum loss, and natal kicks). This might suggest that either common envelope development/survival works differently for DNS (˜10-20 M⊙ stars) than for BH-BH (˜40-100 M⊙ stars) progenitors, or high black hole (BH) natal kicks are needed to meet observational constraints for both types of binaries. Our conclusion is based on a limited number of (21) evolutionary models and is valid within this particular DNS and BH-BH isolated binary formation scenario.

  6. Revisiting El Niño Modokis

    Science.gov (United States)

    Marathe, Shamal; Ashok, Karumuri; Swapna, P.; Sabin, T. P.

    2015-12-01

    The suggestion that there exist two types of El Niño in the tropical Pacific has generated a debate in the community. Applying various linear and non-linear approaches and composite analysis technique on observed and reanalyzed climate datasets primarily for the 1950-2010 period, we revisit the variability of the tropical Pacific in the light of this debate. Our objective is to examine whether the proposed El Niño Modokis need a classification distinct from canonical El Niños. Even if the distinction is subject to short data records, we demonstrate that the El Niño Modoki events indeed display a seasonal evolution and teleconnections different from the canonical El Niños, and that the distinction is not subject to inclusion of the two extreme El Niños 1982 and 1997 as canonical El Niños. We show that the El Niño Modoki events are not an artifact associated with the orthogonality constraint associated with the EOF technique. Our cluster analysis shows that evolutions of the canonical El Niño and El Niño Modokis through various seasons differ from one another. Importantly, the dynamic and thermodynamic air-sea coupling strength is distinctly different between the El Niño Modoki and the canonical El Niño events. We find that, dynamic feedback intensity is stronger for El Niño Modoki (canonical El Niño) during boreal summer (winter); though the air-sea coupling strength, a major contributor to Bjerknes feedback, is maximum for Modokis during the developing stages, it decreases thereafter. In case of thermodynamic feedback intensity, SST-wind-evaporation feedback is dominant for El Niños while SST-SHF feedback is important during El Niño Modokis. However, we find that the thermodynamic feedback values significantly differ across the flux datasets.

  7. Clifford Algebra Implying Three Fermion Generations Revisited

    International Nuclear Information System (INIS)

    Krolikowski, W.

    2002-01-01

    The author's idea of algebraic compositeness of fundamental particles, allowing to understand the existence in Nature of three fermion generations, is revisited. It is based on two postulates. Primo, for all fundamental particles of matter the Dirac square-root procedure √p 2 → Γ (N) ·p works, leading to a sequence N=1, 2, 3, ... of Dirac-type equations, where four Dirac-type matrices Γ (N) μ are embedded into a Clifford algebra via a Jacobi definition introducing four ''centre-of-mass'' and (N - 1) x four ''relative'' Dirac-type matrices. These define one ''centre-of-mass'' and N - 1 ''relative'' Dirac bispinor indices. Secundo, the ''centre-of-mass'' Dirac bispinor index is coupled to the Standard Model gauge fields, while N - 1 ''relative'' Dirac bispinor indices are all free indistinguishable physical objects obeying Fermi statistics along with the Pauli principle which requires the full antisymmetry with respect to ''relative'' Dirac indices. This allows only for three Dirac-type equations with N = 1, 3, 5 in the case of N odd, and two with N = 2, 4 in the case of N even. The first of these results implies unavoidably the existence of three and only three generations of fundamental fermions, namely leptons and quarks, as labelled by the Standard Model signature. At the end, a comment is added on the possible shape of Dirac 3 x 3 mass matrices for four sorts of spin-1/2 fundamental fermions appearing in three generations. For charged leptons a prediction is m τ = 1776.80 MeV, when the input of experimental m e and m μ is used. (author)

  8. THE INFLUENCE OF DESTINATION IMAGE AND TOURIST SATISFACTION TOWARD REVISIT INTENTION OF SETU BABAKAN BETAWI CULTURAL VILLAGE

    OpenAIRE

    Wibowo, Setyo Ferry; Sazali, Adnan; Kresnamurti R. P., Agung

    2016-01-01

    The purpose of this research are: 1) To find out the description of destination image, tourist satisfaction, and revisit intention of Betawi cultural village Setu Babakan, 2) test empirically the influence of destination image toward revisit intention of Betawi cultural village Setu Babakan, 3) test empirically the influence of tourist satisfaction toward revisit intention of Betawi cultural village Setu Babakan, 4) test empirically the influence of destination image toward revisit intention ...

  9. Enantioseparation with liquid membranes

    NARCIS (Netherlands)

    Gössi, Angelo; Riedl, Wolfgang; Schuur, Boelo

    Chiral resolution of racemic products is a challenging and important task in the pharmaceutical, agrochemical, flavor, polymer and fragrances industries. One of the options for these challenging separations is to use liquid membranes. Although liquid membranes have been known for almost four decades

  10. Porous ceramic membranes

    NARCIS (Netherlands)

    Biesheuvel, P.M.; Biesheuvel, Pieter Maarten

    2000-01-01

    Synthetic membranes are increasingly used for energy-efficient separation of liquid and gaseous mixtures in household applications, environmental technology and the chemical and energy industry. Besides, membranes are used in component-specific sensors in gas and liquid streams, preferably combined

  11. Polymide gas separation membranes

    Science.gov (United States)

    Ding, Yong; Bikson, Benjamin; Nelson, Joyce Katz

    2004-09-14

    Soluble polyamic acid salt (PAAS) precursors comprised of tertiary and quaternary amines, ammonium cations, sulfonium cations, or phosphonium cations, are prepared and fabricated into membranes that are subsequently imidized and converted into rigid-rod polyimide articles, such as membranes with desirable gas separation properties. A method of enhancing solubility of PAAS polymers in alcohols is also disclosed.

  12. Membrane module assembly

    Science.gov (United States)

    Kaschemekat, Jurgen

    1994-01-01

    A membrane module assembly adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation.

  13. Elastic membranes in confinement.

    Science.gov (United States)

    Bostwick, J B; Miksis, M J; Davis, S H

    2016-07-01

    An elastic membrane stretched between two walls takes a shape defined by its length and the volume of fluid it encloses. Many biological structures, such as cells, mitochondria and coiled DNA, have fine internal structure in which a membrane (or elastic member) is geometrically 'confined' by another object. Here, the two-dimensional shape of an elastic membrane in a 'confining' box is studied by introducing a repulsive confinement pressure that prevents the membrane from intersecting the wall. The stage is set by contrasting confined and unconfined solutions. Continuation methods are then used to compute response diagrams, from which we identify the particular membrane mechanics that generate mitochondria-like shapes. Large confinement pressures yield complex response diagrams with secondary bifurcations and multiple turning points where modal identities may change. Regions in parameter space where such behaviour occurs are then mapped. © 2016 The Author(s).

  14. Membrane projection lithography

    Energy Technology Data Exchange (ETDEWEB)

    Burckel, David Bruce; Davids, Paul S; Resnick, Paul J; Draper, Bruce L

    2015-03-17

    The various technologies presented herein relate to a three dimensional manufacturing technique for application with semiconductor technologies. A membrane layer can be formed over a cavity. An opening can be formed in the membrane such that the membrane can act as a mask layer to the underlying wall surfaces and bottom surface of the cavity. A beam to facilitate an operation comprising any of implantation, etching or deposition can be directed through the opening onto the underlying surface, with the opening acting as a mask to control the area of the underlying surfaces on which any of implantation occurs, material is removed, and/or material is deposited. The membrane can be removed, a new membrane placed over the cavity and a new opening formed to facilitate another implantation, etching, or deposition operation. By changing the direction of the beam different wall/bottom surfaces can be utilized to form a plurality of structures.

  15. Membrane technology and applications

    International Nuclear Information System (INIS)

    Khalil, F.H.

    1997-01-01

    The main purpose of this dissertation is to prepare and characterize some synthetic membranes obtained by radiation-induced graft copolymerization of and A Am unitary and binary system onto nylon-6 films. The optimum conditions at which the grafting process proceeded homogeneously were determined. Some selected properties of the prepared membranes were studied. Differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), x-ray diffraction (XRD), mechanical properties and U.V./vis, instruments and techniques were used to characterize the prepared membranes. The use of such membranes for the decontamination of radioactive waste and some heavy metal ions as water pollutants were investigated. These grafted membranes showed good cation exchange properties and may be of practical interest in waste water treatment whether this water was radioactive or not. 4 tabs., 68 figs., 146 refs

  16. Revisit ocean thermal energy conversion system

    International Nuclear Information System (INIS)

    Huang, J.C.; Krock, H.J.; Oney, S.K.

    2003-01-01

    by-products, especially drinking water, aquaculture and mariculture, can easily translate into billions of dollars in business opportunities. The current status of the OTEC system definitely deserves to be carefully revisited. This paper will examine recent major advancements in technology, evaluate costs and effectiveness, and assess the overall market environment of the OTEC system and describe its great renewable energy potential and overall benefits to the nations of the world

  17. The timeline of the lunar bombardment: Revisited

    Science.gov (United States)

    Morbidelli, A.; Nesvorny, D.; Laurenz, V.; Marchi, S.; Rubie, D. C.; Elkins-Tanton, L.; Wieczorek, M.; Jacobson, S.

    2018-05-01

    The timeline of the lunar bombardment in the first Gy of Solar System history remains unclear. Basin-forming impacts (e.g. Imbrium, Orientale), occurred 3.9-3.7 Gy ago, i.e. 600-800 My after the formation of the Moon itself. Many other basins formed before Imbrium, but their exact ages are not precisely known. There is an intense debate between two possible interpretations of the data: in the cataclysm scenario there was a surge in the impact rate approximately at the time of Imbrium formation, while in the accretion tail scenario the lunar bombardment declined since the era of planet formation and the latest basins formed in its tail-end. Here, we revisit the work of Morbidelli et al. (2012) that examined which scenario could be compatible with both the lunar crater record in the 3-4 Gy period and the abundance of highly siderophile elements (HSE) in the lunar mantle. We use updated numerical simulations of the fluxes of asteroids, comets and planetesimals leftover from the planet-formation process. Under the traditional assumption that the HSEs track the total amount of material accreted by the Moon since its formation, we conclude that only the cataclysm scenario can explain the data. The cataclysm should have started ∼ 3.95 Gy ago. However we also consider the possibility that HSEs are sequestered from the mantle of a planet during magma ocean crystallization, due to iron sulfide exsolution (O'Neil, 1991; Rubie et al., 2016). We show that this is likely true also for the Moon, if mantle overturn is taken into account. Based on the hypothesis that the lunar magma ocean crystallized about 100-150 My after Moon formation (Elkins-Tanton et al., 2011), and therefore that HSEs accumulated in the lunar mantle only after this timespan, we show that the bombardment in the 3-4 Gy period can be explained in the accretion tail scenario. This hypothesis would also explain why the Moon appears so depleted in HSEs relative to the Earth. We also extend our analysis of the

  18. Enthalpy-Entropy Compensation (EEC) Effect: A Revisit.

    Science.gov (United States)

    Pan, Animesh; Biswas, Tapas; Rakshit, Animesh K; Moulik, Satya P

    2015-12-31

    A short account of the developments and perspectives of IKR (iso-kinetic relation) and EEC (enthalpy (H) - entropy (S) compensation) has been presented. The IKR and EEC are known to be extra thermodynamic or empirical correlations though linear H-S correlation can be thermodynamically deduced. Attempt has also been made to explain the phenomena in terms of statistical thermodynamics. In this study, we have briefly revisited the fundamentals of both IKR and EEC from kinetic and thermodynamic grounds. A detailed revisit of the EEC phenomenon on varied kinetic and equilibrium processes has been also presented. Possible correlations among the free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes of different similar and nonsimilar chemical processes under varied conditions have been discussed with possible future projections.

  19. Dynamics of Shape Fluctuations of Quasi-spherical Vesicles Revisited

    DEFF Research Database (Denmark)

    Miao, L.; Lomholt, Michael Andersen; Kleis, J.

    2002-01-01

    In this paper, the dynamics of spontaneous shape fluctuations of a single, giant quasi-spherical vesicle formed from a single lipid species is revisited theoretically. A coherent physical theory for the dynamics is developed based on a number of fundamental principles and considerations, and a sy......In this paper, the dynamics of spontaneous shape fluctuations of a single, giant quasi-spherical vesicle formed from a single lipid species is revisited theoretically. A coherent physical theory for the dynamics is developed based on a number of fundamental principles and considerations......, and a systematic formulation of the theory is also established. From-the systematic theoretical formulation, an analytical description of the dynamics of shape fluctuations of quasi-spherical vesicles is derived. In particular, in developing the theory we have made a new interpretation of some...

  20. Serotype-specific mortality from invasive Streptococcus pneumoniae disease revisited

    DEFF Research Database (Denmark)

    Martens, Pernille; Worm, Signe Westring; Lundgren, Bettina

    2004-01-01

    Serotype-specific mortality from invasive Streptococcus pneumoniae disease revisited.Martens P, Worm SW, Lundgren B, Konradsen HB, Benfield T. Department of Infectious Diseases 144, Hvidovre University Hospital, DK-2650 Hvidovre, Denmark. pernillemartens@yahoo.com BACKGROUND: Invasive infection w...... pneumococcal disease. The limitations of the current polysaccharide pneumococcal vaccine warrant the development of alternative vaccines. We suggest that the virulence of pneumococcal serotypes should be considered in the design of novel vaccines....

  1. Hospital revisit rate after a diagnosis of conversion disorder.

    Science.gov (United States)

    Merkler, Alexander E; Parikh, Neal S; Chaudhry, Simriti; Chait, Alanna; Allen, Nicole C; Navi, Babak B; Kamel, Hooman

    2016-04-01

    To estimate the hospital revisit rate of patients diagnosed with conversion disorder (CD). Using administrative data, we identified all patients discharged from California, Florida and New York emergency departments (EDs) and acute care hospitals between 2005 and 2011 with a primary discharge diagnosis of CD. Patients discharged with a primary diagnosis of seizure or transient global amnesia (TGA) served as control groups. Our primary outcome was the rate of repeat ED visits and hospital admissions after initial presentation. Poisson regression was used to compare rates between diagnosis groups while adjusting for demographic characteristics. We identified 7946 patients discharged with a primary diagnosis of CD. During a mean follow-up of 3.0 (±1.6) years, patients with CD had a median of three (IQR, 1-9) ED or inpatient revisits, compared with 0 (IQR, 0-2) in patients with TGA and 3 (IQR, 1-7) in those with seizures. Revisit rates were 18.25 (95% CI, 18.10 to 18.40) visits per 100 patients per month in those with CD, 3.90 (95% CI, 3.84 to 3.95) in those with TGA and 17.78 (95% CI, 17.75 to 17.81) in those with seizures. As compared to CD, the incidence rate ratio for repeat ED visits or hospitalisations was 0.89 (95% CI, 0.86 to 0.93) for seizure disorder and 0.32 (95% CI 0.31 to 0.34) for TGA. CD is associated with a substantial hospital revisit rate. Our findings suggest that CD is not an acute, time-limited response to stress, but rather that CD is a manifestation of a broader pattern of chronic neuropsychiatric disease. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  2. Quark matter revisited with non-extensive MIT bag model

    Science.gov (United States)

    Cardoso, Pedro H. G.; Nunes da Silva, Tiago; Deppman, Airton; Menezes, Débora P.

    2017-10-01

    In this work we revisit the MIT bag model to describe quark matter within both the usual Fermi-Dirac and the Tsallis statistics. We verify the effects of the non-additivity of the latter by analysing two different pictures: the first order phase transition of the QCD phase diagram and stellar matter properties. While the QCD phase diagram is visually affected by the Tsallis statistics, the resulting effects on quark star macroscopic properties are barely noticed.

  3. Discussion of "Computational Electrocardiography: Revisiting Holter ECG Monitoring".

    Science.gov (United States)

    Baumgartner, Christian; Caiani, Enrico G; Dickhaus, Hartmut; Kulikowski, Casimir A; Schiecke, Karin; van Bemmel, Jan H; Witte, Herbert

    2016-08-05

    This article is part of a For-Discussion-Section of Methods of Information in Medicine about the paper "Computational Electrocardiography: Revisiting Holter ECG Monitoring" written by Thomas M. Deserno and Nikolaus Marx. It is introduced by an editorial. This article contains the combined commentaries invited to independently comment on the paper of Deserno and Marx. In subsequent issues the discussion can continue through letters to the editor.

  4. Quark matter revisited with non-extensive MIT bag model

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Pedro H.G.; Nunes da Silva, Tiago; Menezes, Debora P. [Universidade Federal de Santa Catarina, Departamento de Fisica, CFM, Florianopolis (Brazil); Deppman, Airton [Instituto de Fisica da Universidade de Sao Paulo, Sao Paulo (Brazil)

    2017-10-15

    In this work we revisit the MIT bag model to describe quark matter within both the usual Fermi-Dirac and the Tsallis statistics. We verify the effects of the non-additivity of the latter by analysing two different pictures: the first order phase transition of the QCD phase diagram and stellar matter properties. While the QCD phase diagram is visually affected by the Tsallis statistics, the resulting effects on quark star macroscopic properties are barely noticed. (orig.)

  5. Radiative corrections to neutrino deep inelastic scattering revisited

    International Nuclear Information System (INIS)

    Arbuzov, Andrej B.; Bardin, Dmitry Yu.; Kalinovskaya, Lidia V.

    2005-01-01

    Radiative corrections to neutrino deep inelastic scattering are revisited. One-loop electroweak corrections are re-calculated within the automatic SANC system. Terms with mass singularities are treated including higher order leading logarithmic corrections. Scheme dependence of corrections due to weak interactions is investigated. The results are implemented into the data analysis of the NOMAD experiment. The present theoretical accuracy in description of the process is discussed

  6. Place attachment and social legitimacy: Revisiting the sustainable entrepreneurship journey

    OpenAIRE

    Kibler, E; Fink, M; Lang, R; Munoz, PA

    2015-01-01

    This paper revisits the sustainable entrepreneurship journey by introducing a ‘place- based’ sustainable venture path model. We suggest that distinguishing between emo- tional (‘caring about the place’) and instrumental (‘using the place’) place attachment of sustainable entrepreneurs deepens our understanding of how place-based challenges of sustainable venture legitimacy are managed over time. We conclude with avenues for future sustainable entrepreneurship research.

  7. PERSISTENT PUPILLARY MEMBRANE OR ACCESSORY IRIS MEMBRANE?.

    Science.gov (United States)

    Gavriş, Monica; Horge, Ioan; Avram, Elena; Belicioiu, Roxana; Olteanu, Ioana Alexandra; Kedves, Hanga

    2015-01-01

    Frequently, in literature and curent practice, accessory iris membrane (AIM) and persistant pupillary membrane (PPM) are confused. Both AIM and PPM are congenital iris anomalies in which fine or thick iris strands arrise form the collarette and obscure the pupil. AIM, which is also called iris duplication, closely resembles the normal iris tissue in color and thickness and presents a virtual second pseudopupil aperture in the centre while PPM even in its extreme forms presents as a translucent or opaque membranous structure that extends across the pupil and has no pseudopupil. Mydriatiscs, laser treatment or surgery is used to clear the visual axis and optimize visual development. Surgical intervention is reserved for large, dense AIMs and PPMs. Our patient, a 29 year old male, has come with bilateral dense AIM, bilateral compound hyperopic astigmatism, BCVA OD = 0.6, BCVA OS = 0.4, IOP OU = 17 mmHg. To improve the visual acuity of the patient we decided to do a bilateral membranectomy, restoring in this way transparency of the visual axis. After surgery, the visual acuity improved to BCVA OD= 0.8, BCVA OS=0.8.

  8. Fuel cell membrane humidification

    Science.gov (United States)

    Wilson, Mahlon S.

    1999-01-01

    A polymer electrolyte membrane fuel cell assembly has an anode side and a cathode side separated by the membrane and generating electrical current by electrochemical reactions between a fuel gas and an oxidant. The anode side comprises a hydrophobic gas diffusion backing contacting one side of the membrane and having hydrophilic areas therein for providing liquid water directly to the one side of the membrane through the hydrophilic areas of the gas diffusion backing. In a preferred embodiment, the hydrophilic areas of the gas diffusion backing are formed by sewing a hydrophilic thread through the backing. Liquid water is distributed over the gas diffusion backing in distribution channels that are separate from the fuel distribution channels.

  9. Extracorporeal membrane oxygenation

    Science.gov (United States)

    Extracorporeal membrane oxygenation (ECMO) is a treatment that uses a pump to circulate blood through an artificial lung back into the bloodstream of a very ill baby. This system provides heart-lung bypass support ...

  10. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-02-01

    This factsheet describes a research project that will focus on the development and application of nonporous high gas flux perfluoro membranes with high temperature rating and excellent chemical resistance.

  11. Inverse colloidal crystal membranes for hydrophobic interaction membrane chromatography.

    Science.gov (United States)

    Vu, Anh T; Wang, Xinying; Wickramasinghe, S Ranil; Yu, Bing; Yuan, Hua; Cong, Hailin; Luo, Yongli; Tang, Jianguo

    2015-08-01

    Hydrophobic interaction membrane chromatography has gained interest due to its excellent performance in the purification of humanized monoclonal antibodies. The membrane material used in hydrophobic interaction membrane chromatography has typically been commercially available polyvinylidene fluoride. In this contribution, newly developed inverse colloidal crystal membranes that have uniform pores, high porosity and, therefore, high surface area for protein binding are used as hydrophobic interaction membrane chromatography membranes for humanized monoclonal antibody immunoglobulin G purification. The capacity of the inverse colloidal crystal membranes developed here is up to ten times greater than commercially available polyvinylidene fluoride membranes with a similar pore size. This work highlights the importance of developing uniform pore size high porosity membranes in order to maximize the capacity of hydrophobic interaction membrane chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Fabrication of electrospun nanofibrous membranes for membrane distillation application

    KAUST Repository

    Francis, Lijo

    2013-02-01

    Nanofibrous membranes of Matrimid have been successfully fabricated using an electrospinning technique under optimized conditions. Nanofibrous membranes are found to be highly hydrophobic with a high water contact angle of 130°. Field emission scanning electron microscopy and pore size distribution analysis revealed the big pore size structure of electrospun membranes to be greater than 2 μm and the pore size distribution is found to be narrow. Flat sheet Matrimid membranes were fabricated via casting followed by phase inversion. The morphology, pore size distribution, and water contact angle were measured and compared with the electrospun membranes. Both membranes fabricated by electrospinning and phase inversion techniques were tested in a direct contact membrane distillation process. Electrospun membranes showed high water vapor flux of 56 kg/m2-h, which is very high compared to the casted membrane as well as most of the fabricated and commercially available highly hydrophobic membranes. ©2013 Desalination Publications.

  13. Bacterial membrane proteomics.

    Science.gov (United States)

    Poetsch, Ansgar; Wolters, Dirk

    2008-10-01

    About one quarter to one third of all bacterial genes encode proteins of the inner or outer bacterial membrane. These proteins perform essential physiological functions, such as the import or export of metabolites, the homeostasis of metal ions, the extrusion of toxic substances or antibiotics, and the generation or conversion of energy. The last years have witnessed completion of a plethora of whole-genome sequences of bacteria important for biotechnology or medicine, which is the foundation for proteome and other functional genome analyses. In this review, we discuss the challenges in membrane proteome analysis, starting from sample preparation and leading to MS-data analysis and quantification. The current state of available proteomics technologies as well as their advantages and disadvantages will be described with a focus on shotgun proteomics. Then, we will briefly introduce the most abundant proteins and protein families present in bacterial membranes before bacterial membrane proteomics studies of the last years will be presented. It will be shown how these works enlarged our knowledge about the physiological adaptations that take place in bacteria during fine chemical production, bioremediation, protein overexpression, and during infections. Furthermore, several examples from literature demonstrate the suitability of membrane proteomics for the identification of antigens and different pathogenic strains, as well as the elucidation of membrane protein structure and function.

  14. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2000-10-01

    This is the third quarterly report on oxygen Transport Ceramic Membranes. In the following, the report describes the progress made by our university partners in Tasks 1 through 6, experimental apparatus that was designed and built for various tasks of this project, thermodynamic calculations, where applicable and work planned for the future. (Task 1) Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. (Task 2) Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. (Task 3) Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. (Task 4) Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. (Task 5) Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. (Task 6) Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

  15. Biomimetic membranes and methods of making biomimetic membranes

    Science.gov (United States)

    Rempe, Susan; Brinker, Jeffrey C.; Rogers, David Michael; Jiang, Ying-Bing; Yang, Shaorong

    2016-11-08

    The present disclosure is directed to biomimetic membranes and methods of manufacturing such membranes that include structural features that mimic the structures of cellular membrane channels and produce membrane designs capable of high selectivity and high permeability or adsorptivity. The membrane structure, material and chemistry can be selected to perform liquid separations, gas separation and capture, ion transport and adsorption for a variety of applications.

  16. Parallel artificial liquid membrane extraction

    DEFF Research Database (Denmark)

    Gjelstad, Astrid; Rasmussen, Knut Einar; Parmer, Marthe Petrine

    2013-01-01

    This paper reports development of a new approach towards analytical liquid-liquid-liquid membrane extraction termed parallel artificial liquid membrane extraction. A donor plate and acceptor plate create a sandwich, in which each sample (human plasma) and acceptor solution is separated by an arti...... by an artificial liquid membrane. Parallel artificial liquid membrane extraction is a modification of hollow-fiber liquid-phase microextraction, where the hollow fibers are replaced by flat membranes in a 96-well plate format....

  17. Smart membranes for monitoring membrane based desalination processes

    KAUST Repository

    Laleg-Kirati, Taous-Meriem

    2017-10-12

    Various examples are related to smart membranes for monitoring membrane based process such as, e.g., membrane distillation processes. In one example, a membrane, includes a porous surface and a plurality of sensors (e.g., temperature, flow and/or impedance sensors) mounted on the porous surface. In another example, a membrane distillation (MD) process includes the membrane. Processing circuitry can be configured to monitor outputs of the plurality of sensors. The monitored outputs can be used to determine membrane degradation, membrane fouling, or to provide an indication of membrane replacement or cleaning. The sensors can also provide temperatures or temperature differentials across the porous surface, which can be used to improve modeling or control the MD process.

  18. Polyurethane Nanofiber Membranes for Waste Water Treatment by Membrane Distillation

    Directory of Open Access Journals (Sweden)

    T. Jiříček

    2017-01-01

    Full Text Available Self-sustained electrospun polyurethane nanofiber membranes were manufactured and tested on a direct-contact membrane distillation unit in an effort to find the optimum membrane thickness to maximize flux rate and minimize heat losses across the membrane. Also salt retention and flux at high salinities up to 100 g kg−1 were evaluated. Even though the complex structure of nanofiber layers has extreme specific surface and porosity, membrane performance was surprisingly predictable; the highest flux was achieved with the thinnest membranes and the best energy efficiency was achieved with the thickest membranes. All membranes had salt retention above 99%. Nanotechnology offers the potential to find modern solutions for desalination of waste waters, by introducing new materials with revolutionary properties, but new membranes must be developed according to the target application.

  19. Recent advances on polymeric membranes for membrane reactors

    KAUST Repository

    Buonomenna, M. G.

    2012-06-24

    Membrane reactors are generally applied in high temperature reactions (>400 °C). In the field of fine chemical synthesis, however, much milder conditions are generally applicable and polymeric membranes were applied without their damage. The successful use of membranes in membrane reactors is primary the result of two developments concerning: (i) membrane materials and (ii) membrane structures. The selection of a suited material and preparation technique depends on the application the membrane is to be used in. In this chapter a review of up to date literature about polymers and configuration catalyst/ membranes used in some recent polymeric membrane reactors is given. The new emerging concept of polymeric microcapsules as catalytic microreactors has been proposed. © 2012 Bentham Science Publishers. All rights reserved.

  20. Physics of biological membranes

    Science.gov (United States)

    Mouritsen, Ole G.

    The biological membrane is a complex system consisting of an aqueous biomolecular planar aggregate of predominantly lipid and protein molecules. At physiological temperatures, the membrane may be considered a thin (˜50Å) slab of anisotropic fluid characterized by a high lateral mobility of the various molecular components. A substantial fraction of biological activity takes place in association with membranes. As a very lively piece of condensed matter, the biological membrane is a challenging research topic for both the experimental and theoretical physicists who are facing a number of fundamental physical problems including molecular self-organization, macromolecular structure and dynamics, inter-macromolecular interactions, structure-function relationships, transport of energy and matter, and interfacial forces. This paper will present a brief review of recent theoretical and experimental progress on such problems, with special emphasis on lipid bilayer structure and dynamics, lipid phase transitions, lipid-protein and lipid-cholesterol interactions, intermembrane forces, and the physical constraints imposed on biomembrane function and evolution. The paper advocates the dual point of view that there are a number of interesting physics problems in membranology and, at the same time, that the physical properties of biomembranes are important regulators of membrane function.

  1. Membranes and Fluorescence microscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2009-01-01

    Fluorescence spectroscopy-based techniques using conventional fluorimeters have been extensively applied since the late 1960s to study different aspects of membrane-related phenomena, i.e., mainly relating to lipid-lipid and lipid-protein (peptide) interactions. Even though fluorescence spectrosc......Fluorescence spectroscopy-based techniques using conventional fluorimeters have been extensively applied since the late 1960s to study different aspects of membrane-related phenomena, i.e., mainly relating to lipid-lipid and lipid-protein (peptide) interactions. Even though fluorescence...... spectroscopy approaches provide very valuable structurally and dynamically related information on membranes, they generally produce mean parameters from data collected on bulk solutions of many vesicles and lack direct information on the spatial organization at the level of single membranes, a quality that can...... be provided by microscopy-related techniques. In this chapter, I will attempt to summarize representative examples concerning how microscopy (which provides information on membrane lateral organization by direct visualization) and spectroscopy techniques (which provides information about molecular interaction...

  2. Biopores/membrane proteins in synthetic polymer membranes.

    Science.gov (United States)

    Garni, Martina; Thamboo, Sagana; Schoenenberger, Cora-Ann; Palivan, Cornelia G

    2017-04-01

    Mimicking cell membranes by simple models based on the reconstitution of membrane proteins in lipid bilayers represents a straightforward approach to understand biological function of these proteins. This biomimetic strategy has been extended to synthetic membranes that have advantages in terms of chemical and mechanical stability, thus providing more robust hybrid membranes. We present here how membrane proteins and biopores have been inserted both in the membrane of nanosized and microsized compartments, and in planar membranes under various conditions. Such bio-hybrid membranes have new properties (as for example, permeability to ions/molecules), and functionality depending on the specificity of the inserted biomolecules. Interestingly, membrane proteins can be functionally inserted in synthetic membranes provided these have appropriate properties to overcome the high hydrophobic mismatch between the size of the biomolecule and the membrane thickness. Functional insertion of membrane proteins and biopores in synthetic membranes of compartments or in planar membranes is possible by an appropriate selection of the amphiphilic copolymers, and conditions of the self-assembly process. These hybrid membranes have new properties and functionality based on the specificity of the biomolecules and the nature of the synthetic membranes. Bio-hybrid membranes represent new solutions for the development of nanoreactors, artificial organelles or active surfaces/membranes that, by further gaining in complexity and functionality, will promote translational applications. This article is part of a Special Issue entitled: Lipid order/lipid defects and lipid-control of protein activity edited by Dirk Schneider. Copyright © 2016. Published by Elsevier B.V.

  3. Liver plasma membranes: an effective method to analyze membrane proteome.

    Science.gov (United States)

    Cao, Rui; Liang, Songping

    2012-01-01

    Plasma membrane proteins are critical for the maintenance of biological systems and represent important targets for the treatment of disease. The hydrophobicity and low abundance of plasma membrane proteins make them difficult to analyze. The protocols given here are the efficient isolation/digestion procedures for liver plasma membrane proteomic analysis. Both protocol for the isolation of plasma membranes and protocol for the in-gel digestion of gel-embedded plasma membrane proteins are presented. The later method allows the use of a high detergent concentration to achieve efficient solubilization of hydrophobic plasma membrane proteins while avoiding interference with the subsequent LC-MS/MS analysis.

  4. Membranes and pathophysiological mineralization.

    Science.gov (United States)

    Roszkowska, Monika; Strzelecka-Kiliszek, Agnieszka; Magne, David; Pikula, Slawomir; Bessueille, Laurence

    Vascular calcification accompanies the pathological process of atherosclerotic plaque formation. Artery calcification results from trans-differentiation of vascular smooth muscle cells (VSMCs) into cells resembling mineralization-competent cells such as osteoblasts and chondrocytes. The activity of tissue-nonspecific alkaline phosphatase (TNAP), a GPI-anchored enzyme necessary for physiological mineralization, is induced in VSMCs in response to inflammation. TNAP achieves its mineralizing function being anchored to plasma membrane of mineralizing cells and to the surface of their derived matrix vesicles (MVs), and numerous important reports indicate that membranes play a crucial role in initiating the crystal formation. In this review, we would like to highlight various functions of lipids and proteins associated to membranes at different stages of both physiological mineralization and vascular calcification, with an emphasis on the pathological process of atherosclerotic plaque formation.

  5. Characterization of graphene membranes

    Science.gov (United States)

    O'Hern, Sean; Lee, Jongho; Jain, Tarun; Karnik, Rohit; Idrobo, Juan; Laoui, Tahar; Atieh, Motaz

    2011-11-01

    Graphene, which exhibits very high breaking strength, atomistic thickness, and the ability to maintain stable nanometer-scale pores, has the potential to be a superior membrane material in both liquid- and gas-phase separation processes. We have recently demonstrated high-quality transfer of ~1 cm2 LPCVD graphene from copper foil to 200 nm polycarbonate track etch membranes with less than 0.3% of the area constituting holes or tears in the graphene, which is essential for characterizing transport through graphene. Through gallium ion bombardment we have introduced nanometer-scale pores in the transferred graphene and will report on the molecular and ionic transport through these membranes. Funded by the Center for Clean Energy and Water at MIT and KFUPM.

  6. Hybrid Filter Membrane

    Science.gov (United States)

    Laicer, Castro; Rasimick, Brian; Green, Zachary

    2012-01-01

    Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of

  7. Circular revisit orbits design for responsive mission over a single target

    Science.gov (United States)

    Li, Taibo; Xiang, Junhua; Wang, Zhaokui; Zhang, Yulin

    2016-10-01

    The responsive orbits play a key role in addressing the mission of Operationally Responsive Space (ORS) because of their capabilities. These capabilities are usually focused on supporting specific targets as opposed to providing global coverage. One subtype of responsive orbits is repeat coverage orbit which is nearly circular in most remote sensing applications. This paper deals with a special kind of repeating ground track orbit, referred to as circular revisit orbit. Different from traditional repeat coverage orbits, a satellite on circular revisit orbit can visit a target site at both the ascending and descending stages in one revisit cycle. This typology of trajectory allows a halving of the traditional revisit time and does a favor to get useful information for responsive applications. However the previous reported numerical methods in some references often cost lots of computation or fail to obtain such orbits. To overcome this difficulty, an analytical method to determine the existence conditions of the solutions to revisit orbits is presented in this paper. To this end, the mathematical model of circular revisit orbit is established under the central gravity model and the J2 perturbation. A constraint function of the circular revisit orbit is introduced, and the monotonicity of that function has been studied. The existent conditions and the number of such orbits are naturally worked out. Taking the launch cost into consideration, optimal design model of circular revisit orbit is established to achieve a best orbit which visits a target twice a day in the morning and in the afternoon respectively for several days. The result shows that it is effective to apply circular revisit orbits in responsive application such as reconnoiter of natural disaster.

  8. Membrane adsorber for endotoxin removal

    Directory of Open Access Journals (Sweden)

    Karina Moita de Almeida

    Full Text Available ABSTRACT The surface of flat-sheet nylon membranes was modified using bisoxirane as the spacer and polyvinyl alcohol as the coating polymer. The amino acid histidine was explored as a ligand for endotoxins, aiming at its application for endotoxin removal from aqueous solutions. Characterization of the membrane adsorber, analysis of the depyrogenation procedures and the evaluation of endotoxin removal efficiency in static mode are discussed. Ligand density of the membranes was around 7 mg/g dry membrane, allowing removal of up to 65% of the endotoxins. The performance of the membrane adsorber prepared using nylon coated with polyvinyl alcohol and containing histidine as the ligand proved superior to other membrane adsorbers reported in the literature. The lack of endotoxin adsorption on nylon membranes without histidine confirmed that endotoxin removal was due to the presence of the ligand at the membrane surface. Modified membranes were highly stable, exhibiting a lifespan of approximately thirty months.

  9. Fouling resistant membrane spacers

    KAUST Repository

    Ghaffour, Noreddine

    2017-10-12

    Disclosed herein are spacers having baffle designs and perforations for efficiently and effectively separating one or more membrane layers a membrane filtration system. The spacer (504) includes a body (524) formed at least in part by baffles (520) that are interconnected, and the baffles define boundaries of openings or apertures (525) through a thickness direction of the body of the spacer. Alternatively or additionally, passages or perforations (526A, 526B) may be present in the spacer layer or baffles for fluid flow there through, with the passages and baffles having a numerous different shapes and sizes.

  10. Mitigating leaks in membranes

    Energy Technology Data Exchange (ETDEWEB)

    Karnik, Rohit N.; Bose, Suman; Boutilier, Michael S.H.; Hadjiconstantinou, Nicolas G.; Jain, Tarun Kumar; O' Hern, Sean C.; Laoui, Tahar; Atieh, Muataz A.; Jang, Doojoon

    2018-02-27

    Two-dimensional material based filters, their method of manufacture, and their use are disclosed. In one embodiment, a membrane may include an active layer including a plurality of defects and a deposited material associated with the plurality of defects may reduce flow therethrough. Additionally, a majority of the active layer may be free from the material. In another embodiment, a membrane may include a porous substrate and an atomic layer deposited material disposed on a surface of the porous substrate. The atomic layer deposited material may be less hydrophilic than the porous substrate and an atomically thin active layer may be disposed on the atomic layer deposited material.

  11. Organic separations with membranes

    International Nuclear Information System (INIS)

    Funk, E.W.

    1993-01-01

    This paper presents an overview of present and emerging applications of membrane technology for the separation and purification of organic materials. This technology is highly relevant for programs aimed at minimizing waste in processing and in the treatment of gaseous and liquid effluents. Application of membranes for organic separation is growing rapidly in the petrochemical industry to simplify processing and in the treatment of effluents, and it is expected that this technology will be useful in numerous other industries including the processing of nuclear waste materials

  12. Membrane order in the plasma membrane and endocytic recycling compartment.

    Science.gov (United States)

    Iaea, David B; Maxfield, Frederick R

    2017-01-01

    The cholesterol content of membranes plays an important role in organizing membranes for signal transduction and protein trafficking as well as in modulating the biophysical properties of membranes. While the properties of model or isolated membranes have been extensively studied, there has been little evaluation of internal membranes in living cells. Here, we use a Nile Red based probe, NR12S, and ratiometric live cell imaging, to analyze the membrane order of the plasma membrane and endocytic recycling compartment. We find that after a brief incubation to allow endocytosis, NR12S is distributed between the plasma membrane and the endocytic recycling compartment. The NR12S reports that the endocytic recycling compartment is more highly ordered than the plasma membrane. We also find that the plasma membrane and the endocytic recycling compartment are differentially affected by altering cellular cholesterol levels. The membrane order of the plasma membrane, but not the endocytic recycling compartment, is altered significantly when cellular cholesterol content is increased or decreased by 20%. These results demonstrate that changes in cellular cholesterol differentially alter membrane order within different organelles.

  13. Dimensional analysis of membrane distillation flux through fibrous membranes

    Science.gov (United States)

    Mauter, Meagan

    We developed a dimensional-analysis-based empirical modeling method for membrane distillation (MD) flux that is adaptable for novel membrane structures. The method makes fewer simplifying assumptions about membrane pore geometry than existing theoretical (i.e. mechanistic) models, and allows selection of simple, easily-measureable membrane characteristics as structural parameters. Furthermore, the model does not require estimation of membrane surface temperatures; it accounts for convective heat transfer to the membrane surface without iterative fitting of mass and heat transfer equations. The Buckingham-Pi dimensional analysis method is tested for direct contact membrane distillation (DCMD) using non-woven/fibrous structures as the model membrane material. Twelve easily-measured variables to describe DCMD operating conditions, fluid properties, membrane structures, and flux were identified and combined into eight dimensionless parameters. These parameters were regressed using experimentally-collected data for multiple electrospun membrane types and DCMD system conditions, achieving R2 values >95%. We found that vapor flux through isotropic fibrous membranes can be estimated using only membrane thickness, solid fraction, and fiber diameter as structural parameters. Buckingham-Pi model DCMD flux predictions compare favorably with previously-developed empirical and theoretical models, and suggest this simple yet theoretically-grounded empirical modeling method can be used practically for predicting MD vapor flux from membrane structural parameters.

  14. Fouling in Membrane Distillation, Osmotic Distillation and Osmotic Membrane Distillation

    Directory of Open Access Journals (Sweden)

    Mourad Laqbaqbi

    2017-03-01

    Full Text Available Various membrane separation processes are being used for seawater desalination and treatment of wastewaters in order to deal with the worldwide water shortage problem. Different types of membranes of distinct morphologies, structures and physico-chemical characteristics are employed. Among the considered membrane technologies, membrane distillation (MD, osmotic distillation (OD and osmotic membrane distillation (OMD use porous and hydrophobic membranes for production of distilled water and/or concentration of wastewaters for recovery and recycling of valuable compounds. However, the efficiency of these technologies is hampered by fouling phenomena. This refers to the accumulation of organic/inorganic deposits including biological matter on the membrane surface and/or in the membrane pores. Fouling in MD, OD and OMD differs from that observed in electric and pressure-driven membrane processes such electrodialysis (ED, membrane capacitive deionization (MCD, reverse osmosis (RO, nanofiltration (NF, ultrafiltration (UF, microfiltration (MF, etc. Other than pore blockage, fouling in MD, OD and OMD increases the risk of membrane pores wetting and reduces therefore the quantity and quality of the produced water or the concentration efficiency of the process. This review deals with the observed fouling phenomena in MD, OD and OMD. It highlights different detected fouling types (organic fouling, inorganic fouling and biofouling, fouling characterization techniques as well as various methods of fouling reduction including pretreatment, membrane modification, membrane cleaning and antiscalants application.

  15. A practical method of predicting client revisit intention in a hospital setting.

    Science.gov (United States)

    Lee, Kyun Jick

    2005-01-01

    Data mining (DM) models are an alternative to traditional statistical methods for examining whether higher customer satisfaction leads to higher revisit intention. This study used a total of 906 outpatients' satisfaction data collected from a nationwide survey interviews conducted by professional interviewers on a face-to-face basis in South Korea, 1998. Analyses showed that the relationship between overall satisfaction with hospital services and outpatients' revisit intention, along with word-of-mouth recommendation as intermediate variables, developed into a nonlinear relationship. The five strongest predictors of revisit intention were overall satisfaction, intention to recommend to others, awareness of hospital promotion, satisfaction with physician's kindness, and satisfaction with treatment level.

  16. Microencapsulation within crosslinked polyethyleneimine membranes.

    Science.gov (United States)

    Poncelet, D; Alexakis, T; Poncelet de Smet, B; Neufeld, R J

    1994-01-01

    A microencapsulation technique is proposed involving the formation of a polyethyleneimine (PEI) membrane crosslinked by an acid dichloride. The membranes were formed at pH 8 in a non-polar solvent, conditions which are better suited for the encapsulation of biocatalysts or fragile biochemicals than those using polyamide membranes. The mean diameter and size distribution of the PEI microcapsules were similar to that observed with nylon membranes. The resultant microcapsules were spherical, free-flowing with a strong membrane. The mass of membrane was seen to be independent of the reaction time (1-4 min), insensitive to the PEI concentration and proportional to the concentration of crosslinking agent.

  17. Giant plasma membrane vesicles: models for understanding membrane organization.

    Science.gov (United States)

    Levental, Kandice R; Levental, Ilya

    2015-01-01

    The organization of eukaryotic membranes into functional domains continues to fascinate and puzzle cell biologists and biophysicists. The lipid raft hypothesis proposes that collective lipid interactions compartmentalize the membrane into coexisting liquid domains that are central to membrane physiology. This hypothesis has proven controversial because such structures cannot be directly visualized in live cells by light microscopy. The recent observations of liquid-liquid phase separation in biological membranes are an important validation of the raft hypothesis and enable application of the experimental toolbox of membrane physics to a biologically complex phase-separated membrane. This review addresses the role of giant plasma membrane vesicles (GPMVs) in refining the raft hypothesis and expands on the application of GPMVs as an experimental model to answer some of key outstanding problems in membrane biology. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Adaptive silicone-membrane lenses: planar vs. shaped membrane

    CSIR Research Space (South Africa)

    Schneider, F

    2009-08-01

    Full Text Available In this paper the authors compare the performance and optical quality of two types of adaptive fluidic silicone-membrane lenses. The membranes feature either a homogeneous thickness, or it is shaped resulting in an inhomogeneous cross...

  19. A control center design revisited: learning from users’ appropriation

    DEFF Research Database (Denmark)

    Souza da Conceição, Carolina; Cordeiro, Cláudia

    2014-01-01

    This paper aims to present the lessons learned during a control center design project by revisiting another control center from the same company designed two and a half years before by the same project team. In light of the experience with the first project and its analysis, the designers...... and researchers had important feedback already used to suggest changes for the second project. The opportunity to learn from a previous project was unique, but the knowledge gotten out of it shows the importance of having this feedback from project to project instead of just ‘repeating’ previously used design...

  20. Small-angle scattering theory revisited: Photocurrent and spatial localization

    DEFF Research Database (Denmark)

    Basse, N.P.; Zoletnik, S.; Michelsen, Poul

    2005-01-01

    In this paper theory on collective scattering measurements of electron density fluctuations in fusion plasmas is revisited. We present the first full derivation of the expression for the photocurrent beginning at the basic scattering concepts. Thereafter we derive detailed expressions for the auto......- and crosspower spectra obtained from measurements. These are discussed and simple simulations made to elucidate the physical meaning of the findings. In this context, the known methods of obtaining spatial localization are discussed and appraised. Where actual numbers are applied, we utilize quantities from two...

  1. Crop Classification Using Short-Revisit Multitemporal SAR Data

    DEFF Research Database (Denmark)

    Skriver, Henning; Mattia, Francesco; Satalino, Giuseppe

    2011-01-01

    Classification of crops and other land cover types is an important application of both optical/infrared and SAR satellite data. It is already an import application of present satellite systems, as it will be for planned missions, such as the Sentinels. An airborne SAR data set with a short revisit......, and that cross-polarized backscatter produces the best results, with errors down to 3%–6% at the two frequencies. There is a trade-off between the polarimetric information and the multitemporal information, where the best overall results are obtained using the multitemporal information. If only a few...

  2. Revisited neoclassical transport theory for steep, collisional plasma edge profiles

    International Nuclear Information System (INIS)

    Rogister, A.L.

    1994-01-01

    Published neoclassical results are misleading as concerns the plasma edge for they do not adequately take the peculiar local conditions into account, in particular the fact that the density and temperature variation length-scales are quite small. Coupled novel neoclassical equations obtain, not only for the evolution of the density and temperatures, but also for the radial electric field and the evolution of the parallel ion momentum: gyro-stresses and inertia indeed upset the otherwise de facto ambipolarity of particle transport and a radial electric field necessarily builds up. The increased nonlinear character of these revisited neoclassical equations widens the realm of possible plasma behaviors. (author)

  3. Revisiting the issue of elite capture in participatory initiatives

    DEFF Research Database (Denmark)

    Lund, Jens Friis; Saito-Jensen, Moeko

    2013-01-01

    Based on case studies of two communities implementing participatory forestry in Tanzania and India, we revisit the issue of elite capture of participatory initiatives. Our cases illustrate how initial elite capture of the participatory initiatives is circumvented over time through various forms...... of resistance orchestrated by initially disadvantaged groups. Based on the cases we argue that studies of elite capture should be based on in-depth and longitudinal empirical investigations that carefully characterize forms and outcomes of elite capture and consider both the changing dynamics of social settings...

  4. REVISITING A CLASSIC: THE PARKER–MOFFATT PROBLEM

    Energy Technology Data Exchange (ETDEWEB)

    Pezzi, O.; Servidio, S.; Valentini, F.; Malara, F.; Veltri, P. [Dipartimento di Fisica, Università della Calabria, 87036 Rende (CS) (Italy); Parashar, T. N.; Yang, Y.; Matthaeus, W. H. [Department of Physics and Astronomy, University of Delaware, DE 19716 (United States); Vásconez, C. L. [Departamento de Física, Escuela Politécnica Nacional, Quito (Ecuador)

    2017-01-10

    The interaction of two colliding Alfvén wave packets is described here by means of magnetohydrodynamics (MHD) and hybrid kinetic numerical simulations. The MHD evolution revisits the theoretical insights described by Moffatt, Parker, Kraichnan, Chandrasekhar, and Elsässer in which the oppositely propagating large-amplitude wave packets interact for a finite time, initiating turbulence. However, the extension to include compressive and kinetic effects, while maintaining the gross characteristics of the simpler classic formulation, also reveals intriguing features that go beyond the pure MHD treatment.

  5. Rural-Nonrural Disparities in Postsecondary Educational Attainment Revisited

    Science.gov (United States)

    Byun, Soo-yong; Meece, Judith L.; Irvin, Matthew J.

    2013-01-01

    Using data from the National Educational Longitudinal Study, this study revisited rural-nonrural disparities in educational attainment by considering a comprehensive set of factors that constrain and support youth's college enrollment and degree completion. Results showed that rural students were more advantaged in community social resources compared to nonrural students, and these resources were associated with a significant increase in the likelihood of bachelor's degree attainment. Yet results confirmed that rural students lagged behind nonrural students in attaining a bachelor's degree largely due to their lower socioeconomic background. The findings present a more comprehensive picture of the complexity of geographic residence in shaping college enrollment and degree attainment. PMID:24285873

  6. Dissipation in relativistic pair-plasma reconnection: revisited

    Science.gov (United States)

    Zenitani, Seiji

    2018-01-01

    Basic properties of relativistic magnetic reconnection in electron–positron pair plasmas are investigated by using a particle-in-cell (PIC) simulation. We first revisit a problem by Hesse and Zenitani (2007 Phys. Plasmas 14 112102), who examined the kinetic Ohm’s law across the X line. We formulate a relativistic Ohm’s law by decomposing the stress–energy tensor. Then, the role of the new term, called the heat-flow inertial term, is examined in the PIC simulation data. We further evaluate the energy balance in the reconnection system. These analyses demonstrate physically transparent ways to diagnose relativistic kinetic data.

  7. Hydrogen-selective membrane

    Science.gov (United States)

    Collins, J.P.; Way, J.D.

    1997-07-29

    A hydrogen-selective membrane comprises a tubular porous ceramic support having a palladium metal layer deposited on an inside surface of the ceramic support. The thickness of the palladium layer is greater than about 10 {micro}m but typically less than about 20 {micro}m. The hydrogen permeation rate of the membrane is greater than about 1.0 moles/m{sup 2} s at a temperature of greater than about 500 C and a transmembrane pressure difference of about 1,500 kPa. Moreover, the hydrogen-to-nitrogen selectivity is greater than about 600 at a temperature of greater than about 500 C and a transmembrane pressure of about 700 kPa. Hydrogen can be separated from a mixture of gases using the membrane. The method may include the step of heating the mixture of gases to a temperature of greater than about 400 C and less than about 1000 C before the step of flowing the mixture of gases past the membrane. The mixture of gases may include ammonia. The ammonia typically is decomposed to provide nitrogen and hydrogen using a catalyst such as nickel. The catalyst may be placed inside the tubular ceramic support. The mixture of gases may be supplied by an industrial process such as the mixture of exhaust gases from the IGCC process. 9 figs.

  8. Fusion of biological membranes

    Indian Academy of Sciences (India)

    small hemifusion diaphragm. To obtain a direct view of the fusion process, we have carried out extensive simulations of two bilayers, composed of block copolymers, which are immersed in a solvent which favors one of the blocks. As in the biological case, the membranes are placed under tension. This is essential as fusion ...

  9. Cell Membrane Coating Nanotechnology.

    Science.gov (United States)

    Fang, Ronnie H; Kroll, Ashley V; Gao, Weiwei; Zhang, Liangfang

    2018-03-27

    Nanoparticle-based therapeutic, prevention, and detection modalities have the potential to greatly impact how diseases are diagnosed and managed in the clinic. With the wide range of nanomaterials available, the rational design of nanocarriers on an application-specific basis has become increasingly commonplace. Here, a comprehensive overview is provided on an emerging platform: cell-membrane-coating nanotechnology. As a fundamental unit of biology, cells carry out a wide range of functions, including the remarkable ability to interface and interact with their surrounding environment. Instead of attempting to replicate such functions via synthetic techniques, researchers are now directly leveraging naturally derived cell membranes as a means of bestowing nanoparticles with enhanced biointerfacing capabilities. This top-down technique is facile, highly generalizable, and has the potential to greatly augment existing nanocarriers. Further, the introduction of a natural membrane substrate onto nanoparticles surfaces has enabled additional applications beyond those traditionally associated with nanomedicine. Despite its relative youth, there exists an impressive body of literature on cell membrane coating, which is covered here in detail. Overall, there is still significant room for development, as researchers continue to refine existing workflows while finding new and exciting applications that can take advantage of this developing technology. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Fusion of biological membranes

    Indian Academy of Sciences (India)

    Logo of the Indian Academy of Sciences. Indian Academy of ... Home; Journals; Pramana – Journal of Physics; Volume 64; Issue 6. Fusion of biological ... The process of membrane fusion has been examined by Monte Carlo simulation, and is found to be very different than the conventional picture. The differences in ...

  11. Bioelectrochemistry II membrane phenomena

    CERN Document Server

    Blank, M

    1987-01-01

    This book contains the lectures of the second course devoted to bioelectro­ chemistry, held within the framework of the International School of Biophysics. In this course another very large field of bioelectrochemistry, i. e. the field of Membrane Phenomena, was considered, which itself consists of several different, but yet related subfields. Here again, it can be easily stated that it is impossible to give a complete and detailed picture of all membrane phenomena of biological interest in a short course of about one and half week. Therefore the same philosophy, as the one of the first course, was followed, to select a series of lectures at postgraduate level, giving a synthesis of several membrane phenomena chosen among the most'important ones. These lectures should show the large variety of membrane-regulated events occurring in living bodies, and serve as sound interdisciplinary basis to start a special­ ized study of biological phenomena, for which the investigation using the dual approach, physico-che...

  12. Fusion of biological membranes

    Indian Academy of Sciences (India)

    Abstract. The process of membrane fusion has been examined by Monte Carlo simu- lation, and is found to be very different than the conventional picture. The differences in mechanism lead to several predictions, in particular that fusion is accompanied by tran- sient leakage. This prediction has recently been verified.

  13. Extracorporeal membrane oxygenation (ECMO)

    African Journals Online (AJOL)

    Extracorporeal membrane oxygenation (ECMO) is increasingly being employed in South African intensive care units for the management of patients with refractory hypoxaemia and for haemodynamic support, particularly following cardiothoracic procedures. ECMO is expensive, however, and there is a danger that this ...

  14. Fusion of biological membranes

    Indian Academy of Sciences (India)

    The process of membrane fusion has been examined by Monte Carlo simulation, and is found to be very different than the conventional picture. The differences in mechanism lead to several predictions, in particular that fusion is accompanied by transient leakage. This prediction has recently been verified. Self-consistent ...

  15. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2001-02-01

    This is the fifth quarterly report on a new study to develop a ceramic membrane/metal joint. Results of wetting experiments on commercially available Nickel based brazing alloys on perovskite surfaces are described. Additionally, experimental and numerical investigations on the strength of concentric ceramic/metal joints are presented.

  16. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2003-01-01

    In the present quarter, the possibility of using a more complex interfacial engineering approach to the development of reliable and stable oxygen transport perovskite ceramic membranes/metal seals is discussed. Experiments are presented and ceramic/metal interactions are characterized. Crack growth and fracture toughness of the membrane in the reducing conditions are also discussed. Future work regarding this approach is proposed are evaluated for strength and fracture in oxygen gradient conditions. Oxygen gradients are created in tubular membranes by insulating the inner surface from the reducing environment by platinum foils. Fracture in these test conditions is observed to have a gradient in trans and inter-granular fracture as opposed to pure trans-granular fracture observed in homogeneous conditions. Fracture gradients are reasoned to be due to oxygen gradient set up in the membrane, variation in stoichiometry across the thickness and due to varying decomposition of the parent perovskite. The studies are useful in predicting fracture criterion in actual reactor conditions and in understanding the initial evolution of fracture processes.

  17. Nanodisc-solubilized membrane protein library reflects the membrane proteome

    OpenAIRE

    Marty, Michael T.; Wilcox, Kyle C.; Klein, William L.; Sligar, Stephen G.

    2013-01-01

    The isolation and identification of unknown membrane proteins offers the prospect of discovering new pharmaceutical targets and identifying key biochemical receptors. However, interactions between membrane protein targets and soluble ligands are difficult to study in vitro due to the insolubility of membrane proteins in non-detergent systems. Nanodiscs, nanoscale discoidal lipid bilayers encircled by a membrane scaffold protein belt, have proven to be an effective platform to solubilize membr...

  18. Membrane fission by protein crowding.

    Science.gov (United States)

    Snead, Wilton T; Hayden, Carl C; Gadok, Avinash K; Zhao, Chi; Lafer, Eileen M; Rangamani, Padmini; Stachowiak, Jeanne C

    2017-04-18

    Membrane fission, which facilitates compartmentalization of biological processes into discrete, membrane-bound volumes, is essential for cellular life. Proteins with specific structural features including constricting rings, helical scaffolds, and hydrophobic membrane insertions are thought to be the primary drivers of fission. In contrast, here we report a mechanism of fission that is independent of protein structure-steric pressure among membrane-bound proteins. In particular, random collisions among crowded proteins generate substantial pressure, which if unbalanced on the opposite membrane surface can dramatically increase membrane curvature, leading to fission. Using the endocytic protein epsin1 N-terminal homology domain (ENTH), previously thought to drive fission by hydrophobic insertion, our results show that membrane coverage correlates equally with fission regardless of the hydrophobicity of insertions. Specifically, combining FRET-based measurements of membrane coverage with multiple, independent measurements of membrane vesiculation revealed that fission became spontaneous as steric pressure increased. Further, fission efficiency remained equally potent when helices were replaced by synthetic membrane-binding motifs. These data challenge the view that hydrophobic insertions drive membrane fission, suggesting instead that the role of insertions is to anchor proteins strongly to membrane surfaces, amplifying steric pressure. In line with these conclusions, even green fluorescent protein (GFP) was able to drive fission efficiently when bound to the membrane at high coverage. Our conclusions are further strengthened by the finding that intrinsically disordered proteins, which have large hydrodynamic radii yet lack a defined structure, drove fission with substantially greater potency than smaller, structured proteins.

  19. Dialysis membranes for blood purification.

    Science.gov (United States)

    Sakai, K

    2000-01-01

    All of the artificial membranes in industrial use, such as a reverse-osmosis membrane, dialysis membrane, ultrafiltration membrane, microfiltration membrane and gas separation membrane, also have therapeutic applications. The most commonly used artificial organ is the artificial kidney, a machine that performs treatment known as hemodialysis. This process cleanses the body of a patient with renal failure by dialysis and filtration, simple physicochemical processes. Hemodialysis membranes are used to remove accumulated uremic toxins, excess ions and water from the patient via the dialysate, and to supply (deficit) insufficient ions from the dialysate. Dialysis membranes used clinically in the treatment of patients with renal failure account for by far the largest volume of membranes used worldwide; more than 70 million square meters are used a year. Almost all dialyzers now in use are of the hollow-fiber type. A hollow-fiber dialyzer contains a bundle of approximately 10000 hollow fibers, each with an inner diameter of about 200 microm when wet. The membrane thickness is about 20-45 microm, and the length is 160-250 mm. The walls of the hollow fibers function as the dialysis membrane. Various materials, including cellulose-based materials and synthetic polymers, are used for dialysis membranes. This paper reviews blood purification, hemodialysis and dialysis membranes.

  20. Autophagosomal membranes assemble at ER-plasma membrane contact sites.

    Science.gov (United States)

    Nascimbeni, Anna Chiara; Codogno, Patrice; Morel, Etienne

    2017-01-01

    The biogenesis of autophagosome, the double membrane bound organelle related to macro-autophagy, is a complex event requiring numerous key-proteins and membrane remodeling events. Our recent findings identify the extended synaptotagmins, crucial tethers of Endoplasmic Reticulum-plasma membrane contact sites, as key-regulators of this molecular sequence.

  1. Alternative energy efficient membrane bioreactor using reciprocating submerged membrane.

    Science.gov (United States)

    Ho, J; Smith, S; Roh, H K

    2014-01-01

    A novel membrane bioreactor (MBR) pilot system, using membrane reciprocation instead of air scouring, was operated at constant high flux and daily fluctuating flux to demonstrate its application under peak and diurnal flow conditions. Low and stable transmembrane pressure was achieved at 40 l/m(2)/h (LMH) by use of repetitive membrane reciprocation. The results reveal that the inertial forces acting on the membrane fibers effectively propel foulants from the membrane surface. Reciprocation of the hollow fiber membrane is beneficial for the constant removal of solids that may build up on the membrane surface and inside the membrane bundle. The membrane reciprocation in the reciprocating MBR pilot consumed less energy than coarse air scouring used in conventional MBR systems. Specific energy consumption for the membrane reciprocation was 0.072 kWh/m(3) permeate produced at 40 LMH flux, which is 75% less than for a conventional air scouring system as reported in literature without consideration of energy consumption for biological aeration (0.29 kWh/m(3)). The daily fluctuating flux test confirmed that the membrane reciprocation is effective to handle fluctuating flux up to 50 LMH. The pilot-scale reciprocating MBR system successfully demonstrated that fouling can be controlled via 0.43 Hz membrane reciprocation with 44 mm or higher amplitude.

  2. Nanodisc-solubilized membrane protein library reflects the membrane proteome.

    Science.gov (United States)

    Marty, Michael T; Wilcox, Kyle C; Klein, William L; Sligar, Stephen G

    2013-05-01

    The isolation and identification of unknown membrane proteins offers the prospect of discovering new pharmaceutical targets and identifying key biochemical receptors. However, interactions between membrane protein targets and soluble ligands are difficult to study in vitro due to the insolubility of membrane proteins in non-detergent systems. Nanodiscs, nanoscale discoidal lipid bilayers encircled by a membrane scaffold protein belt, have proven to be an effective platform to solubilize membrane proteins and have been used to study a wide variety of purified membrane proteins. This report details the incorporation of an unbiased population of membrane proteins from Escherichia coli membranes into Nanodiscs. This solubilized membrane protein library (SMPL) forms a soluble in vitro model of the membrane proteome. Since Nanodiscs contain isolated proteins or small complexes, the SMPL is an ideal platform for interactomics studies and pull-down assays of membrane proteins. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the protein population before and after formation of the Nanodisc library indicates that a large percentage of the proteins are incorporated into the library. Proteomic identification of several prominent bands demonstrates the successful incorporation of outer and inner membrane proteins into the Nanodisc library.

  3. Revisiting the Gram-negative lipoprotein paradigm.

    Science.gov (United States)

    LoVullo, Eric D; Wright, Lori F; Isabella, Vincent; Huntley, Jason F; Pavelka, Martin S

    2015-05-01

    The processing of lipoproteins (Lpps) in Gram-negative bacteria is generally considered an essential pathway. Mature lipoproteins in these bacteria are triacylated, with the final fatty acid addition performed by Lnt, an apolipoprotein N-acyltransferase. The mature lipoproteins are then sorted by the Lol system, with most Lpps inserted into the outer membrane (OM). We demonstrate here that the lnt gene is not essential to the Gram-negative pathogen Francisella tularensis subsp. tularensis strain Schu or to the live vaccine strain LVS. An LVS Δlnt mutant has a small-colony phenotype on sucrose medium and increased susceptibility to globomycin and rifampin. We provide data indicating that the OM lipoprotein Tul4A (LpnA) is diacylated but that it, and its paralog Tul4B (LpnB), still sort to the OM in the Δlnt mutant. We present a model in which the Lol sorting pathway of Francisella has a modified ABC transporter system that is capable of recognizing and sorting both triacylated and diacylated lipoproteins, and we show that this modified system is present in many other Gram-negative bacteria. We examined this model using Neisseria gonorrhoeae, which has the same Lol architecture as that of Francisella, and found that the lnt gene is not essential in this organism. This work suggests that Gram-negative bacteria fall into two groups, one in which full lipoprotein processing is essential and one in which the final acylation step is not essential, potentially due to the ability of the Lol sorting pathway in these bacteria to sort immature apolipoproteins to the OM. This paper describes the novel finding that the final stage in lipoprotein processing (normally considered an essential process) is not required by Francisella tularensis or Neisseria gonorrhoeae. The paper provides a potential reason for this and shows that it may be widespread in other Gram-negative bacteria. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  4. Membrane Cells for Brine Electrolysis.

    Science.gov (United States)

    Tingle, M.

    1982-01-01

    Membrane cells were developed as alternatives to mercury and diaphragm cells for the electrolysis of brine. Compares the three types of cells, focusing on the advantages and disadvantages of membrane cells. (JN)

  5. Modelling of proteins in membranes

    DEFF Research Database (Denmark)

    Sperotto, Maria Maddalena; May, S.; Baumgaertner, A.

    2006-01-01

    This review describes some recent theories and simulations of mesoscopic and microscopic models of lipid membranes with embedded or attached proteins. We summarize results supporting our understanding of phenomena for which the activities of proteins in membranes are expected to be significantly...... oppositely charged lipid membranes, lipid-induced tilting of proteins embedded in lipid bilayers, protein-induced bilayer deformations, protein insertion and assembly, and lipid-controlled functioning of membrane proteins....

  6. Fundamentals of membrane bioreactors materials, systems and membrane fouling

    CERN Document Server

    Ladewig, Bradley

    2017-01-01

    This book provides a critical, carefully researched, up-to-date summary of membranes for membrane bioreactors. It presents a comprehensive and self-contained outline of the fundamentals of membrane bioreactors, especially their relevance as an advanced water treatment technology. This outline helps to bring the technology to the readers’ attention, and positions the critical topic of membrane fouling as one of the key impediments to its more widescale adoption. The target readership includes researchers and industrial practitioners with an interest in membrane bioreactors.

  7. Cheap Thin Film Oxygen Membranes

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention provides a membrane, comprising a porous support layer a gas tight electronically and ionically conducting membrane layer and a catalyst layer, characterized in that the electronically and ionically conducting membrane layer is formed from a material having a crystallite...

  8. Revisiting the Decision of Death in Hurst v. Florida.

    Science.gov (United States)

    Cooke, Brian K; Ginory, Almari; Zedalis, Jennifer

    2016-12-01

    The United States Supreme Court has considered the question of whether a judge or a jury must make the findings necessary to support imposition of the death penalty in several notable cases, including Spaziano v. Florida (1984), Hildwin v. Florida (1989), and Ring v. Arizona (2002). In 2016, the U.S. Supreme Court revisited the subject in Hurst v. Florida Florida Statute § 921.141 allows the judge, after weighing aggravating and mitigating circumstances, to enter a sentence of life imprisonment or death. Before Hurst, Florida's bifurcated sentencing proceedings included an advisory sentence from jurors and a separate judicial hearing without juror involvement. In Hurst, the Court revisited the question of whether Florida's capital sentencing scheme violates the Sixth Amendment, which requires a jury, not a judge, to find each fact necessary to impose a sentence of death in light of Ring In an eight-to-one decision, the Court reversed the judgment of the Florida Supreme Court, holding that the Sixth Amendment requires a jury to find the aggravating factors necessary for imposing the death penalty. The role of Florida juries in capital sentencing proceedings was thereby elevated from advisory to determinative. We examine the Court's decision and offer commentary regarding this shift from judge to jury in the final imposition of the death penalty and the overall effect of this landmark case. © 2016 American Academy of Psychiatry and the Law.

  9. Association of emergency department albuterol dispensing with pediatric asthma revisits and readmissions.

    Science.gov (United States)

    Hall, A Brad; Novotny, April; Bhisitkul, Donna M; Melton, James; Regan, Tim; Leckie, Maureen

    2017-06-01

    Although pediatric asthma continues to be a highly studied disease, data to suggest clear strategies to decrease asthma related revisits or readmissions is lacking. The purpose of our study was to assess the effect of emergency department (ED) direct dispensing of beta-agonist metered dose inhalers on pediatric asthma ED revisit and readmission rates. We conducted a retrospective cohort study of pediatric patients discharged from the pediatric ED with a diagnosis of asthma. Our primary outcome measured the rate of asthma revisits to the ED or admissions to the hospital within 28 days. Logistic regression analysis was used to assess ED beta-agonist MDI dispensing and revisit and/or readmission as the outcome. A total of 853 patients met eligibility for inclusion in the study, with 657 enrolled in the Baseline group and 196 enrolled in the ED-MDI group. The Baseline group experienced a revisit and readmission rate of 7.0% (46/657) versus 2.6% (5/196) in the ED-MDI group, (p = 0.026). ED direct dispensing of MDIs was found to be independently associated with a decreased risk of revisit or readmission (odds ratio 0.37; 95% confidence interval 0.14-0.95). In our study, ED direct dispensing of beta-agonist MDIs resulted in a reduction in 28-day revisit and readmission to the hospital. Further studies should be performed to evaluate the economic impact of reducing these revisits and readmissions against the costs of maintaining a dispensing program. Our findings may support modification of asthma programs to include dispensing MDIs from the emergency department.

  10. Lutein and atherosclerosis: Belfast versus Toulouse revisited.

    Science.gov (United States)

    Howard, A N; Thurnham, D I

    2017-01-01

    In 1995 we reported that mean plasma lutein concentrations in salaried men and women from Toulouse in Southern France were double those in subjects recruited from general practitioner lists in Belfast, Northern Ireland. At the time incidence of coronary heart disease (CHD) in Southern France was among the lowest in Europe and was much higher in Northern Ireland. Plasma lutein is a biomarker of vegetable and fruit intake and evidence suggests that high concentrations are generally associated with better cardiometabolic health. At the time we speculated like others that role of the carotenoids may well have been to prevent oxidation of lipid in the lipoproteins and so reduce the uptake of oxidised lipid by macrophages and its deposition within the intimal layers of the major arteries as plaque. It is now widely accepted that CHD is an inflammatory disease and that macrophages within plaque together with tissue damage contribute to this inflammation. Stimulated macrophages release cytokines to activate the immune system both locally and systemically. Precursor complement proteins in the blood are activated to assist immune cells in phagocytosis and cell repair. Individuals with a history of arteriosclerosis display significantly higher concentrations of complement factors C3 and C3a than subjects without such a history. Metabolism of C3 via the alternate complement pathway can give rise to the membrane attack complex (MAC) which creates a hole or pore in pathogens or host cells, killing the cell. Recent studies in patients with early age related macular disease (AMD) who also exhibit similar elevated concentrations of complement proteins in their blood, showed supplementation with lutein progressively decreased the amount of the MAC and other complement factors in the blood. Lutein was used in the supplementation experiments because it is an important constituent of macular pigment. Thus the healthier cardiometabolic features displayed by the people in Toulouse may

  11. Membrane Assisted Enzyme Fractionation

    DEFF Research Database (Denmark)

    Yuan, Linfeng

    . In this thesis, separations using crossflow elecro-membrane filtration (EMF) of amino acids, bovine serum albumin (BSA) and industrial enzymes from Novozymes were performed. The main objective of this study was to investigate the technological feasibility of EMF in the application of industrial enzyme...... fractionation, such as removal of a side activity from the main enzyme activity. As a proof-of-concept, amino acids were used as model solution to test the feasibility of EMF in the application of amphoteric molecule separation. A single amino acid was used to illustrate the effect of an electric field...... on the separation performance were very small in the investigated range. The mass transport of each enzyme can be well explained by the Extended-Nernst-Planck equation. Better separation was observed at lower feed concentration, higher solution pH in the investigated range and with a polysulfone (PS) MF membrane...

  12. Building membrane nanopores

    Science.gov (United States)

    Howorka, Stefan

    2017-07-01

    Membrane nanopores--hollow nanoscale barrels that puncture biological or synthetic membranes--have become powerful tools in chemical- and biosensing, and have achieved notable success in portable DNA sequencing. The pores can be self-assembled from a variety of materials, including proteins, peptides, synthetic organic compounds and, more recently, DNA. But which building material is best for which application, and what is the relationship between pore structure and function? In this Review, I critically compare the characteristics of the different building materials, and explore the influence of the building material on pore structure, dynamics and function. I also discuss the future challenges of developing nanopore technology, and consider what the next-generation of nanopore structures could be and where further practical applications might emerge.

  13. Aquaporin-2 membrane targeting

    DEFF Research Database (Denmark)

    Olesen, Emma T B; Fenton, Robert A

    2017-01-01

    The targeting of the water channel aquaporin-2 (AQP2) to the apical plasma membrane of kidney collecting duct principal cells is regulated mainly by the antidiuretic peptide hormone arginine vasopressin (AVP). This process is of crucial importance for the maintenance of body water homeostasis....... In this brief review we assess the role of cyclic adenosine monophosphate (cAMP) and discuss the emerging concept that type 2 AVP receptor (V2R)-mediated AQP2 trafficking is cAMP-independent. the ability of the kidney to concentrate the urine and thereby maintain body water homeostasis depends on targeting....... For example, 1) stimulation with the nonspecific AC activator forskolin increases AQP2 membrane accumulation in a mouse cortical collecting duct cell line [e.g., Norregaard et al. (16)]; 2) cAMP increases CD water permeability (15); 3) the cAMP-activated protein kinase A (PKA) can phosphorylate AQP2 on its...

  14. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2003-01-01

    In the present quarter, experiments are presented on ceramic/metal interactions of Zirconia/Ni-B-Si system and with a thin Ti coating deposited on zirconia surface. Processing of perovskites of LSC, LSF and LSCF composition for evaluation of mechanical properties as a function of environment are begun. The studies are to be in parallel with LSFCO composition to characterize the segregation of cations and slow crack growth in environmental conditions. La{sub 1-x}Sr{sub x}FeO{sub 3-d} has also been characterized for paramagnetic ordering at room temperature and the evolution of magnetic moments as a function of temperature are investigated. Investigation on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane transport.

  15. Application of dynamic membranes in anaerobic membranes in anaerobic membrane bioreactor systems

    OpenAIRE

    Erşahin, M.E.

    2015-01-01

    Anaerobic membrane bioreactors (AnMBRs) physically ensure biomass retention by the application of a membrane filtration process. With growing application experiences from aerobic membrane bioreactors (MBRs), the combination of membrane and anaerobic processes has received much attention and become more attractive and feasible, due to advantages provided by the combination with regard to developments for energy-efficient wastewater treatment. The major drawbacks of MBR technology are related w...

  16. Pulse radiolysis studies of model membranes

    International Nuclear Information System (INIS)

    Heijman, M.G.J.

    1984-01-01

    In this thesis the influence of the structure of membranes on the processes in cell membranes were examined. Different models of the membranes were evaluated. Pulse radiolysis was used as the technique to examine the membranes. (R.B.)

  17. Electrochemical polymer electrolyte membranes

    CERN Document Server

    Fang, Jianhua; Wilkinson, David P

    2015-01-01

    Electrochemical Polymer Electrolyte Membranes covers PEMs from fundamentals to applications, describing their structure, properties, characterization, synthesis, and use in electrochemical energy storage and solar energy conversion technologies. Featuring chapters authored by leading experts from academia and industry, this authoritative text: Discusses cutting-edge methodologies in PEM material selection and fabricationPoints out important challenges in developing PEMs and recommends mitigation strategies to improve PEM performanceAnalyzes the cur

  18. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2000-07-01

    This is the fourth quarterly report on a new study to develop a ceramic membrane/metal joint. The first experiments using the La-Sr-Fe-O ceramic are reported. Some of the analysis performed on the samples obtained are commented upon. A set of experiments to characterize the mechanical strength and thermal fatigue properties of the joints has been designed and begun. Finite element models of joints used to model residual stresses are described.

  19. Novicidin interactions with phospholipid membranes

    DEFF Research Database (Denmark)

    Balakrishnan, Vijay Shankar

    Antimicrobial peptides target bacterial cell membranes and are considered as potential antibiotics. Their interactions with cell membranes are studied using different approaches. This thesis comprises of the biophysical investigations on the antimicrobial peptide Novicidin, interacting...... with liposomes. The lipid-induced changes in the peptide due to membrane binding, and the peptide-induced changes in the membrane properties were investigated using various spectroscopic and calorimetric methods, and the structural and thermodynamic aspects of peptide-lipid interactions are discussed. This helps...... in understanding not only the antimicrobial nature of Novicidin, but also sheds light on the membrane-peptide interactions....

  20. Quantum charged rigid membrane

    International Nuclear Information System (INIS)

    Cordero, Ruben; Molgado, Alberto; Rojas, Efrain

    2011-01-01

    The early Dirac proposal to model the electron as a charged membrane is reviewed. A rigidity term, instead of the natural membrane tension, involving linearly the extrinsic curvature of the worldvolume swept out by the membrane is considered in the action modeling the bubble in the presence of an electromagnetic field. We set up this model as a genuine second-order derivative theory by considering a non-trivial boundary term which plays a relevant part in our formulation. The Lagrangian in question is linear in the bubble acceleration and by means of the Ostrogradski-Hamiltonian approach, we observed that the theory comprises the management of both first- and second-class constraints. We thus show that our second-order approach is robust allowing for a proper quantization. We found an effective quantum potential which permits us to compute bounded states for the system. We comment on the possibility of describing brane world universes by invoking this kind of second-order correction terms.

  1. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Nemser, PhD

    2010-10-01

    There are many industrial catalytic organic reversible reactions with amines or alcohols that have water as one of the products. Many of these reactions are homogeneously catalyzed. In all cases removal of water facilitates the reaction and produces more of the desired chemical product. By shifting the reaction to right we produce more chemical product with little or no additional capital investment. Many of these reactions can also relate to bioprocesses. Given the large number of water-organic compound separations achievable and the ability of the Compact Membrane Systems, Inc. (CMS) perfluoro membranes to withstand these harsh operating conditions, this is an ideal demonstration system for the water-of-reaction removal using a membrane reactor. Enhanced reaction synthesis is consistent with the DOE objective to lower the energy intensity of U.S. industry 25% by 2017 in accord with the Energy Policy Act of 2005 and to improve the United States manufacturing competitiveness. The objective of this program is to develop the platform technology for enhancing homogeneous catalytic chemical syntheses.

  2. Viral membrane fusion

    International Nuclear Information System (INIS)

    Harrison, Stephen C.

    2015-01-01

    Membrane fusion is an essential step when enveloped viruses enter cells. Lipid bilayer fusion requires catalysis to overcome a high kinetic barrier; viral fusion proteins are the agents that fulfill this catalytic function. Despite a variety of molecular architectures, these proteins facilitate fusion by essentially the same generic mechanism. Stimulated by a signal associated with arrival at the cell to be infected (e.g., receptor or co-receptor binding, proton binding in an endosome), they undergo a series of conformational changes. A hydrophobic segment (a “fusion loop” or “fusion peptide”) engages the target-cell membrane and collapse of the bridging intermediate thus formed draws the two membranes (virus and cell) together. We know of three structural classes for viral fusion proteins. Structures for both pre- and postfusion conformations of illustrate the beginning and end points of a process that can be probed by single-virion measurements of fusion kinetics. - Highlights: • Viral fusion proteins overcome the high energy barrier to lipid bilayer merger. • Different molecular structures but the same catalytic mechanism. • Review describes properties of three known fusion-protein structural classes. • Single-virion fusion experiments elucidate mechanism

  3. Embryonic epithelial membrane transporters.

    Science.gov (United States)

    Horster, M

    2000-12-01

    Embryonic epithelial membrane transporters are organized into transporter families that are functional in several epithelial organs, namely, in kidney, lung, pancreas, intestine, and salivary gland. Family members (subtypes) are developmentally expressed in plasma membranes in temporospatial patterns that are 1) similar for one subtype within different organs, like aquaporin-1 (AQP1) in lung and kidney; 2) different between subtypes within the same organ, like the amiloride-sensitive epithelial sodium channel (ENaC) in lung; and 3) apparently matched among members of different transporter families, as alpha-ENaC with AQP1 and -4 in lung and with AQP2 in kidney. Finally, comparison of temporal expression patterns in early embryonic development of transporters from different families [e.g., cystic fibrosis transmembrane conductance regulator (CFTR), ENaC, and outer medullary potassium channel] suggests regulatory activating or inactivating interactions in defined morphogenic periods. This review focuses on embryonic patterns, at the mRNA and immunoprotein level, of the following transporter entities expressed in epithelial cell plasma membranes: ENaC; the chloride transporters CFTR, ClC-2, bumetanide-sensitive Na-K-Cl cotransporter, Cl/OH, and Cl/HCO(3); the sodium glucose transporter-glucose transporter; the sodium/hydrogen exchanger; the sodium-phosphate cotransporter; the ATPases; and AQP. The purpose of this article is to relate temporal and spatial expression patterns in embryonic and in early postnatal epithelia to developmental changes in organ structure and function.

  4. Quantum charged rigid membrane

    Energy Technology Data Exchange (ETDEWEB)

    Cordero, Ruben [Departamento de Fisica, Escuela Superior de Fisica y Matematicas del I.P.N., Unidad Adolfo Lopez Mateos, Edificio 9, 07738 Mexico, D.F. (Mexico); Molgado, Alberto [Unidad Academica de Fisica, Universidad Autonoma de Zacatecas, Zacatecas Zac. (Mexico); Rojas, Efrain, E-mail: cordero@esfm.ipn.mx, E-mail: amolgado@fisica.uaz.edu.mx, E-mail: efrojas@uv.mx [Departamento de Fisica, Facultad de Fisica e Inteligencia Artificial, Universidad Veracruzana, 91000 Xalapa, Veracruz (Mexico)

    2011-03-21

    The early Dirac proposal to model the electron as a charged membrane is reviewed. A rigidity term, instead of the natural membrane tension, involving linearly the extrinsic curvature of the worldvolume swept out by the membrane is considered in the action modeling the bubble in the presence of an electromagnetic field. We set up this model as a genuine second-order derivative theory by considering a non-trivial boundary term which plays a relevant part in our formulation. The Lagrangian in question is linear in the bubble acceleration and by means of the Ostrogradski-Hamiltonian approach, we observed that the theory comprises the management of both first- and second-class constraints. We thus show that our second-order approach is robust allowing for a proper quantization. We found an effective quantum potential which permits us to compute bounded states for the system. We comment on the possibility of describing brane world universes by invoking this kind of second-order correction terms.

  5. Neutrons and model membranes

    Science.gov (United States)

    Fragneto, G.

    2012-11-01

    Current research in membrane protein biophysics highlights the emerging role of lipids in shaping membrane protein function. Cells and organisms have developed sophisticated mechanisms for controlling the lipid composition and many diseases are related to the failure of these mechanisms. One of the recent advances in the field is the discovery of the existence of coexisting micro-domains within a single membrane, important for regulating some signaling pathways. Many important properties of these domains remain poorly characterized. The characterization and analysis of bio-interfaces represent a challenge. Performing measurements on these few nanometer thick, soft, visco-elastic and dynamic systems is close to the limits of the available tools and methods. Neutron scattering techniques including small angle scattering, diffraction, reflectometry as well as inelastic methods are rapidly developing for these studies and are attracting an increasing number of biologists and biophysicists at large facilities. This manuscript will review some recent progress in the field and provide perspectives for future developments. It aims at highlighting neutron reflectometry as a versatile method to tackle questions dealing with the understanding and function of biomembranes and their components. The other important scattering methods are only briefly introduced.

  6. Solid-state membrane module

    Science.gov (United States)

    Gordon, John Howard [Salt Lake City, UT; Taylor, Dale M [Murray, UT

    2011-06-07

    Solid-state membrane modules comprising at least one membrane unit, where the membrane unit has a dense mixed conducting oxide layer, and at least one conduit or manifold wherein the conduit or manifold comprises a dense layer and at least one of a porous layer and a slotted layer contiguous with the dense layer. The solid-state membrane modules may be used to carry out a variety of processes including the separating of any ionizable component from a feedstream wherein such ionizable component is capable of being transported through a dense mixed conducting oxide layer of the membrane units making up the membrane modules. For ease of construction, the membrane units may be planar.

  7. Flux Enhancement in Membrane Distillation Using Nanofiber Membranes

    Directory of Open Access Journals (Sweden)

    T. Jiříček

    2016-01-01

    Full Text Available Membrane distillation (MD is an emerging separation technology, whose largest application potential lies in the desalination of highly concentrated solutions, which are out of the scope of reverse osmosis. Despite many attractive features, this technology is still awaiting large industrial application. The main reason is the lack of commercially available membranes with fluxes comparable to reverse osmosis. MD is a thermal separation process driven by a partial vapour pressure difference. Flux, distillate purity, and thermal efficiency are always in conflict, all three being strictly connected with pore size, membrane hydrophobicity, and thickness. The world has not seen the ideal membrane yet, but nanofibers may offer a solution to these contradictory requirements. Membranes of electrospun PVDF were tested under various conditions on a direct contact (DCMD unit, in order to determine the optimum conditions for maximum flux. In addition, their performance was compared to commonly available PTFE, PE, and PES membranes. It was confirmed that thinner membranes have higher fluxes and a lower distillate purity and also higher energy losses via conduction across the membrane. As both mass and heat transfer are connected, it is best to develop new membranes with a target application in mind, for the specific membrane module and operational conditions.

  8. Membranes, methods of making membranes, and methods of separating gases using membranes

    Science.gov (United States)

    Ho, W. S. Winston

    2012-10-02

    Membranes, methods of making membranes, and methods of separating gases using membranes are provided. The membranes can include at least one hydrophilic polymer, at least one cross-linking agent, at least one base, and at least one amino compound. The methods of separating gases using membranes can include contacting a gas stream containing at least one of CO.sub.2, H.sub.2S, and HCl with one side of a nonporous and at least one of CO.sub.2, H.sub.2S, and HCl selectively permeable membrane such that at least one of CO.sub.2, H.sub.2S, and HCl is selectively transported through the membrane.

  9. Polyazole hollow fiber membranes for direct contact membrane distillation

    KAUST Repository

    Maab, Husnul

    2013-08-07

    Porous hollow fiber membranes were fabricated from fluorinated polyoxadiazole and polytriazole by a dry-wet spinning method for application in desalination of Red Sea water by direct contact membrane distillation (DCMD). The data were compared with commercially available hollow fiber MD membranes prepared from poly(vinylidene fluoride). The membranes were characterized by electron microscopy, liquid entry pressure (LEP), and pore diameter measurements. Finally, the hollow fiber membranes were tested for DCMD. Salt selectivity as high as 99.95% and water fluxes as high as 35 and 41 L m -2 h-1 were demonstrated, respectively, for polyoxadiazole and polytriazole hollow fiber membranes, operating at 80 C feed temperature and 20 C permeate. © 2013 American Chemical Society.

  10. POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

    DEFF Research Database (Denmark)

    2001-01-01

    A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various thermopl......A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various...... thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes...... electrolyte membrane by hot-press. The fuel cell can operate at temperatures up to at least 200 °C with hydrogen-rich fuel containing high ratios of carbon monoxide such as 3 vol% carbon monoxide or more, compared to the carbon monoxide tolerance of 10-20 ppm level for Nafion$m(3)-based polymer electrolyte...

  11. Amodiaquine polymeric membrane electrode.

    Science.gov (United States)

    Malongo, T Kimbeni; Blankert, B; Kambu, O; Amighi, K; Nsangu, J; Kauffmann, J-M

    2006-04-11

    The construction and electrochemical response characteristics of two types of poly(vinyl chloride) (PVC) membrane sensors for the determination of amodiaquine hydrochloride (ADQ.2HCl) are described. The sensing membrane comprised an ion-pair formed between the cationic drug and sodium tetraphenyl borate (NaTPB) or potassium tetrakis(4-chlorophenyl) borate (KTCPB) in a plasticized PVC matrix. Eight PVC membrane ion-selective electrodes were fabricated and studied. Several plasticizers were studied namely, dioctyl phthalate (DOP), 2-nitrophenyl octyl ether (NPOE), dioctyl phenylphosphonate (DOPP) and bis(2-ethylhexyl)adipate (EHA). The sensors display a fast, stable and near-Nernstian response over a relative wide ADQ concentration range (3.2 x 10(-6) to 2.0 x 10(-2) M), with slopes comprised between 28.5 and 31.4 mV dec(-1) in a pH range comprised between pH 3.7 and 5.5. The assay of amodiaquine hydrochloride in pharmaceutical dosage forms using one of the proposed sensors gave average recoveries of 104.3 and 99.9 with R.S.D. of 0.3 and 0.6% for tablets (Malaritab) and a reconstituted powder containing ADQ.2HCl, respectively. The sensor was also used for dissolution profile studies of two drug formulations. The sensor proved to have a good selectivity for ADQ.2HCl over some inorganic and organic compounds, however, berberine chloride interfered significantly. The results were validated by comparison with a spectrophotometric assay according to the USP pharmacopoeia.

  12. Molecularly Imprinted Membranes

    Science.gov (United States)

    Trotta, Francesco; Biasizzo, Miriam; Caldera, Fabrizio

    2012-01-01

    Although the roots of molecularly imprinted polymers lie in the beginning of 1930s in the past century, they have had an exponential growth only 40–50 years later by the works of Wulff and especially by Mosbach. More recently, it was also proved that molecular imprinted membranes (i.e., polymer thin films) that show recognition properties at molecular level of the template molecule are used in their formation. Different procedures and potential application in separation processes and catalysis are reported. The influences of different parameters on the discrimination abilities are also discussed. PMID:24958291

  13. [Juvenile idiopathic epiretinal membrane].

    Science.gov (United States)

    Kontopoulou, K; Krause, S; Fili, S; Hayvazov, S; Schilling, H; Kohlhaas, M

    2016-07-01

    Idiopathic epiretinal membrane (iERM) is very rare in adolescent patients. The pathogenesis remains unclear although the role of hyalocytes is of major importance. The clinical features in young patients are different from those in older patients. We describe a case of iERM in a 15-year-old girl who presented with metamorphopsia of the right eye. This case report presents the basis for the decision for surgical treatment as well as the clinical features at follow-up examination 9 months after surgery.

  14. Oxygen Transport Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay

    2008-08-30

    The focus of this research was to develop new membrane materials by synthesizing different compounds and determining their defect structures, crystallographic structures and electrical properties. In addition to measuring electrical conductivity, oxygen vacancy concentration was also evaluated using thermogravimetry, Neutron diffraction and Moessbauer Spectroscopy. The reducing conditions (CO{sub 2}/CO/H{sub 2} gas mixtures with steam) as encountered in a reactor environment can be expected to have significant influence on the mechanical properties of the oxides membranes. Various La based materials with and without Ti were selected as candidate membrane materials for OTM. The maximum electrical conductivity of LSF in air as a function of temperature was achieved at < 600 C and depends on the concentration of Sr (acceptor dopant). Oxygen occupancy in LSF was estimated using Neutron diffractometry and Moessbauer Spectroscopy by measuring magnetic moment changes depending on the Fe{sup 3+} and Fe{sup 4+} ratio. After extensive studies of candidate materials, lanthanum ferrites (LSF and LSFT) were selected as the favored materials for the oxygen transport membrane (OTM). LSF is a very good material for an OTM because of its high electronic and oxygen ionic conductivity if long term stability and mechanical strength are improved. LSFT not only exhibits p-type behavior in the high oxygen activity regime, but also has n-type conduction in reducing atmospheres. Higher concentrations of oxygen vacancies in the low oxygen activity regime may improve the performance of LSFT as an OTM. The hole concentration is related to the difference in the acceptor and donor concentration by the relation p = [Sr'{sub La}]-[Ti{sm_bullet}{sub Fe}]. The chemical formulation predicts that the hole concentration is, p = 0.8-0.45 or 0.35. Experimental measurements indicated that p is about {approx} 0.35. The activation energy of conduction is 0.2 eV which implies that LSCF conducts via the

  15. Oxygen Transport Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay; N. Nagabhushana; Thomas W. Eagar; Harold R. Larson; Raymundo Arroyave; X.-D Zhou; Y.-W. Shin; H.U. Anderson; Nigel Browning; Alan Jacobson; C.A. Mims

    2003-11-01

    The present quarterly report describes some of the initial studies on newer compositions and also includes newer approaches to address various materials issues such as in metal-ceramic sealing. The current quarter's research has also focused on developing a comprehensive reliability model for predicting the structural behavior of the membranes in realistic conditions. In parallel to industry provided compositions, models membranes have been evaluated in varying environment. Of importance is the behavior of flaws and generation of new flaws aiding in fracture. Fracture mechanics parameters such as crack tip stresses are generated to characterize the influence of environment. Room temperature slow crack growth studies have also been initiated in industry provided compositions. The electrical conductivity and defect chemistry of an A site deficient compound (La{sub 0.55}Sr{sub 0.35}FeO{sub 3}) was studied. A higher conductivity was observed for La{sub 0.55}Sr{sub 0.35}FeO{sub 3} than that of La{sub 0.60}Sr{sub 0.40}FeO{sub 3} and La{sub 0.80}Sr{sub 0.20}FeO{sub 3}. Defect chemistry analysis showed that it was primarily contributed by a higher carrier concentration in La{sub 0.55}Sr{sub 0.35}FeO{sub 3}. Moreover, the ability for oxygen vacancy generation is much higher in La{sub 0.55}Sr{sub 0.35}FeO{sub 3} as well, which indicates a lower bonding strength between Fe-O and a possible higher catalytic activity for La{sub 0.55}Sr{sub 0.35}FeO{sub 3}. The program continued to investigate the thermodynamic properties (stability and phase separation behavior) and total conductivity of prototype membrane materials. The data are needed together with the kinetic information to develop a complete model for the membrane transport. Previous report listed initial measurements on a sample of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-x} prepared in-house by Praxair. Subsequently, a second sample of powder from a larger batch of sample were characterized and compared

  16. Revisiting the curvature cancellation in forced thin sheets

    Science.gov (United States)

    Wang, Jin; Witten, Thomas

    2011-03-01

    We revisit the numerically observed spontaneous vanishing of mean curvature on a developable cone or ``d-cone'' made by pushing a thin elastic sheet into a circular container. The deflection of the d-cone is the distance by which the sheet is pushed into the container. We investigate the ratio of the two principal curvatures versus sheet thickness h over a wider dynamic range than was used previously, holding the deflection and radius fixed. Instead of tending towards 1 as suggested by previous work, we find that the ratio scales as h 1 / 3 . Scaling arguments and geometric variants support this h 1 / 3 finding. Thus the mean curvature does not vanish for very thin sheets as previously claimed. Supported by NSF award DMR 0820054.

  17. Small-angle Scattering Theory Revisited: Photocurrent and Spatial Localization

    Science.gov (United States)

    Basse, N. P.; Zoletnik, S.; Michelsen, P. K.

    2005-01-01

    In this paper theory on collective scattering measurements of electron density fluctuations in fusion plasmas is revisited. We present the first full derivation of the expression for the photocurrent beginning at the basic scattering concepts. Thereafter we derive detailed expressions for the auto- and crosspower spectra obtained from measurements. These are discussed and simple simulations made to elucidate the physical meaning of the findings. In this context, the known methods of obtaining spatial localization are discussed and appraised. Where actual numbers are applied, we utilize quantities from two collective scattering instruments The ALTAIR diagnostic on the Tore Supra tokamak [A Truc et al, "ALTAIR An infrared laser scattering diagnostic on the Tore Supra tokamak", Rev. Sci. Instrum. 63 3716 3724 (1992)] and the LOTUS diagnostic on the Wendelstein 7-AS stellarator [M Saffman et al, "CO2 laser based two-volume collective scattering instrument for spatially localized turbulence measurements", Rev. Sci. Instrum. 72 2579 2592 (2001)].

  18. The General Motor Ability Hypothesis: An Old Idea Revisited.

    Science.gov (United States)

    Hands, Beth; McIntyre, Fleur; Parker, Helen

    2018-04-01

    While specific motor abilities have become a popular explanation for motor performance, the older, alternate notion of a general motor ability should be revisited. Current theories lack consensus, and most motor assessment tools continue to derive a single composite score to represent motor capacity. In addition, results from elegant statistical procedures such as higher order factor analyses, cluster analyses, and Item Response Theory support a more global motor ability. We propose a contemporary model of general motor ability as a unidimensional construct that is emergent and fluid over an individual's lifespan, influenced by both biological and environmental factors. In this article, we address the implications of this model for theory, practice, assessment, and research. Based on our hypothesis and Item Response Theory, our Lifespan Motor Ability Scale can identify motor assessment tasks that are relevant and important across varied phases of lifespan development.

  19. The random field Blume-Capel model revisited

    Science.gov (United States)

    Santos, P. V.; da Costa, F. A.; de Araújo, J. M.

    2018-04-01

    We have revisited the mean-field treatment for the Blume-Capel model under the presence of a discrete random magnetic field as introduced by Kaufman and Kanner (1990). The magnetic field (H) versus temperature (T) phase diagrams for given values of the crystal field D were recovered in accordance to Kaufman and Kanner original work. However, our main goal in the present work was to investigate the distinct structures of the crystal field versus temperature phase diagrams as the random magnetic field is varied because similar models have presented reentrant phenomenon due to randomness. Following previous works we have classified the distinct phase diagrams according to five different topologies. The topological structure of the phase diagrams is maintained for both H - T and D - T cases. Although the phase diagrams exhibit a richness of multicritical phenomena we did not found any reentrant effect as have been seen in similar models.

  20. Revisiting Johnson and Jackson boundary conditions for granular flows

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tingwen; Benyahia, Sofiane

    2012-07-01

    In this article, we revisit Johnson and Jackson boundary conditions for granular flows. The oblique collision between a particle and a flat wall is analyzed by adopting the classic rigid-body theory and a more realistic semianalytical model. Based on the kinetic granular theory, the input parameter for the partial-slip boundary conditions, specularity coefficient, which is not measurable in experiments, is then interpreted as a function of the particle-wall restitution coefficient, the frictional coefficient, and the normalized slip velocity at the wall. An analytical expression for the specularity coefficient is suggested for a flat, frictional surface with a low frictional coefficient. The procedure for determining the specularity coefficient for a more general problem is outlined, and a working approximation is provided.

  1. Revisiting Estrogen: Efficacy and Safety for Postmenopausal Bone Health

    Directory of Open Access Journals (Sweden)

    Sandra M. Sacco

    2010-01-01

    Full Text Available The rapid decline in endogenous estrogen production that occurs during menopause is associated with significant bone loss and increased risk for fragility fracture. While hormone therapy (HT is an effective means to re-establish endogenous estrogen levels and reduce the risk of future fracture, its use can be accompanied by undesirable side effects such as stroke and breast cancer. In this paper, we revisit the issue of whether HT can be both safe and effective for the prevention of postmenopausal bone loss by examining standard and alternative doses and formulations of HT. The aim of this paper is to continue the dialogue regarding the benefits and controversies of HT with the goal of encouraging the dissemination of-up-to date evidence that may influence how HT is viewed and prescribed.

  2. Brane inflation revisited after WMAP five-year results

    International Nuclear Information System (INIS)

    Ma, Yin-Zhe; Zhang, Xin

    2009-01-01

    In this paper, we revisit brane inflation models with the WMAP five-year results. The WMAP five-year data favor a red-tilted power spectrum of primordial fluctuations at the level of two standard deviations, which is the same as the WMAP three-year result qualitatively, but quantitatively the spectral index is slightly greater than the three-year value. This result can bring impacts on brane inflation models. According to the WMAP five-year data, we find that the KKLMMT model can survive at the level of one standard deviation, and the fine-tuning of the parameter β can be alleviated to a certain extent at the level of two standard deviations

  3. REVISITING THE SCATTERING GREENHOUSE EFFECT OF CO2 ICE CLOUDS

    International Nuclear Information System (INIS)

    Kitzmann, D.

    2016-01-01

    Carbon dioxide ice clouds are thought to play an important role for cold terrestrial planets with thick CO 2 dominated atmospheres. Various previous studies showed that a scattering greenhouse effect by carbon dioxide ice clouds could result in a massive warming of the planetary surface. However, all of these studies only employed simplified two-stream radiative transfer schemes to describe the anisotropic scattering. Using accurate radiative transfer models with a general discrete ordinate method, this study revisits this important effect and shows that the positive climatic impact of carbon dioxide clouds was strongly overestimated in the past. The revised scattering greenhouse effect can have important implications for the early Mars, but also for planets like the early Earth or the position of the outer boundary of the habitable zone

  4. Revisiting the Scattering Greenhouse Effect of CO2 Ice Clouds

    Science.gov (United States)

    Kitzmann, D.

    2016-02-01

    Carbon dioxide ice clouds are thought to play an important role for cold terrestrial planets with thick CO2 dominated atmospheres. Various previous studies showed that a scattering greenhouse effect by carbon dioxide ice clouds could result in a massive warming of the planetary surface. However, all of these studies only employed simplified two-stream radiative transfer schemes to describe the anisotropic scattering. Using accurate radiative transfer models with a general discrete ordinate method, this study revisits this important effect and shows that the positive climatic impact of carbon dioxide clouds was strongly overestimated in the past. The revised scattering greenhouse effect can have important implications for the early Mars, but also for planets like the early Earth or the position of the outer boundary of the habitable zone.

  5. Revisiting the Performance of MACD and RSI Oscillators

    Directory of Open Access Journals (Sweden)

    Terence Tai-Leung Chong

    2014-02-01

    Full Text Available Chong and Ng (2008 find that the Moving Average Convergence–Divergence (MACD and Relative Strength Index (RSI rules can generate excess return in the London Stock Exchange. This paper revisits the performance of the two trading rules in the stock markets of five other OECD countries. It is found that the MACD(12,26,0 and RSI(21,50 rules consistently generate significant abnormal returns in the Milan Comit General and the S&P/TSX Composite Index. In addition, the RSI(14,30/70 rule is also profitable in the Dow Jones Industrials Index. The results shed some light on investors’ belief in these two technical indicators in different developed markets.

  6. Gas separations using inorganic membranes

    Energy Technology Data Exchange (ETDEWEB)

    Egan, B.Z.; Singh, S.P.N. (Oak Ridge National Lab., TN (United States)); Fain, D.E.; Roettger, G.E.; White, D.E. (Oak Ridge K-25 Site, TN (United States))

    1992-04-01

    This report summarizes the results from a research and development program to develop, fabricate, and evaluate inorganic membranes for separating gases at high temperatures and pressures in hostile process environments encountered in fossil energy conversion processes such as coal gasification. The primary emphasis of the research was on the separation and recovery of hydrogen from synthesis gas. Major aspects of the program included assessment of the worldwide research and development activity related to gas separations using inorganic membranes, identification and selection of candidate membrane materials, fabrication and characterization of membranes using porous membrane technology developed at the Oak Ridge K-25 Site, and evaluation of the separations capability of the fabricated membranes in terms of permeabilities and fluxes of gases.

  7. Membrane fouling and wetting in membrane distillation and their mitigation by novel membranes with special wettability.

    Science.gov (United States)

    Wang, Zhangxin; Lin, Shihong

    2017-04-01

    Membrane distillation (MD) has been identified as a promising technology to desalinate the hypersaline wastewaters from fracking and other industries. However, conventional hydrophobic MD membranes are highly susceptible to fouling and/or wetting by the hydrophobic and/or amphiphilic constituents in these wastewaters of complex compositions. This study systematically investigates the impact of the surface wetting properties on the membrane wetting and/or fouling behaviors in MD. Specifically, we compare the wetting and fouling resistance of three types of membranes of different wetting properties, including hydrophobic and omniphobic membranes as well as composite membranes with a hydrophobic substrate and a superhydrophilic top surface. We challenged the MD membranes with hypersaline feed solutions that contained a relatively high concentration of crude oil with and without added synthetic surfactants, Triton X-100. We found that the composite membranes with superhydrophilic top surface were robustly resistant to oil fouling in the absence of Triton X-100, but were subject to pore wetting in the presence of Triton X-100. On the other hand, the omniphobic membranes were easily fouled by oil-in-water emulsion without Triton X-100, but successfully sustained stable MD performance with Triton X-100 stabilized oil-in-water emulsion as the feed solution. In contrast, the conventional hydrophobic membranes failed readily regardless whether Triton X-100 was present, although via different mechanisms. These findings are corroborated by contact angle measures as well as oil-probe force spectroscopy. This study provides a holistic picture regarding how a hydrophobic membrane fails in MD and how we can leverage membranes with special wettability to prevent membrane failure in MD operations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Cell invasion through basement membrane

    OpenAIRE

    Morrissey, Meghan A; Hagedorn, Elliott J; Sherwood, David R

    2013-01-01

    Cell invasion through basement membrane is an essential part of normal development and physiology, and occurs during the pathological progression of human inflammatory diseases and cancer. F-actin-rich membrane protrusions, called invadopodia, have been hypothesized to be the “drill bits” of invasive cells, mediating invasion through the dense, highly cross-linked basement membrane matrix. Though studied in vitro for over 30 y, invadopodia function in vivo has remained elusive. We have recent...

  9. Inorganic membranes and catalytic reactors

    OpenAIRE

    Rangel, Maria do Carmo

    1997-01-01

    Membrane reactors are reviewed with emphasis in their applications in catalysis field. The basic principles of these systems are presented as well as a historical development. The several kinds of catalytic membranes and their preparations are discussed including the problems, needs and challenges to be solved in order to use these reactors in commercial processes. Some applications of inorganic membrane reactors are also shown. It was concluded that these systems have a great potential for i...

  10. Catalytic Membrane Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, T.J.; Brinker, C.J.; Gardner, T.J.; Hughes, R.C.; Sault, A.G.

    1998-12-01

    The proposed "catalytic membrane sensor" (CMS) was developed to generate a device which would selectively identify a specific reagent in a complex mixture of gases. This was to be accomplished by modifying an existing Hz sensor with a series of thin films. Through selectively sieving the desired component from a complex mixture and identifying it by decomposing it into Hz (and other by-products), a Hz sensor could then be used to detect the presence of the select component. The proposed "sandwich-type" modifications involved the deposition of a catalyst layered between two size selective sol-gel layers on a Pd/Ni resistive Hz sensor. The role of the catalyst was to convert organic materials to Hz and organic by-products. The role of the membraneo was to impart both chemical specificity by molecukir sieving of the analyte and converted product streams, as well as controlling access to the underlying Pd/Ni sensor. Ultimately, an array of these CMS elements encompassing different catalysts and membranes were to be developed which would enable improved selectivity and specificity from a compiex mixture of organic gases via pattern recognition methodologies. We have successfully generated a CMS device by a series of spin-coat deposited methods; however, it was determined that the high temperature required to activate the catalyst, destroys the sensor.

  11. Conical Nanopore PC Membranes

    International Nuclear Information System (INIS)

    Clochard, M. C.

    2006-01-01

    Template synthesis can be considered an alternative to conventional lithography methods. It is one way of providing a panel of nanoscale metallic wires, tubes or organic polymeric devices. Our interest is focused on track-etched membranes produced from swift heavy ions bombardment of polymer films. In comparison with self-assembly of block copolymers, this bottom-up approach has the advantage of being economic, it is not time-consuming and it allows track formation of diverse geometries. Tailoring of the conical nanopore tip opening would have a tremendous impact on sensing domain, as well as on fundamental understanding of perpendicular giant magneto Resistance properties observed in metallic multilayered cylindrical nanowires. By combining low-energy heavy ion beam radiation effects with asymmetric etching, the etching temperature and time can be tuned to prepare conical nanopores of controlled geometry from 0.5 to 1μm at the base to a few nanometers at the top. Asymmetric etching onto PC films was pH-monitored at various temperatures in the range of 65 degree to 80 degree. Fluence impact onto track etch pores was also investigated. The pore shape characterization was achieved by electronic microscopy measurements on membrane surfaces and on electrodeposited nanowires. We have also observed a difference in the conical shape of replicated nanowires. Some showed sting shapes and others displayed shell shapes depending on whether a neutralizing agent was used during etching or not

  12. Characterization of Polymeric Nanofiltration Membranes

    Directory of Open Access Journals (Sweden)

    Simoncic, B.

    2007-11-01

    Full Text Available As membrane processes are increasingly used in industrial applications, there is a growing interest in methods of membrane characterization. Traditional membrane characteristics, such as cut-off value and pore size distribution, are being supplemented by membrane surface characteristics, such as charge density or zeta potential and hydrophobicity. This study, therefore, characterizes the three different polymeric membranes used (NFT-50, DL and DK. The molecular mass cut-off (MMCO value was determined using a set of reference solutes within the molecular range 150-600 Da, whereas streaming potential measurements enabled quantification of the surface charge characteristics. Hydrophobicity was studied using contact angle measurements. The results indicated that even though all three membranes had very similar layer compositions which consisted of poly(piperazneamide, as top layers they showed different values of measured quantitive. The NFT-50 membrane had the lowest MMCO value and the most hydrophilic membrane surface, followed by DK and DL. Membrane fouling as measured by flux reduction was determined by streaming potential measurements and accompanied by a positive change in zeta potential.

  13. Track membranes, production, properties, applications

    International Nuclear Information System (INIS)

    Oganesjan, Yu.Ts.

    1994-01-01

    The problems of producing track membranes on heavy ion beams of the Flerov Laboratory are considered. The parameters of the running accelerators and equipment for the irradiation of polymer foils are presented. The process of production of track membranes based on different polymeric materials and various applications of the membranes are described. Special attention is given to the principally new applications and devices developed at the Laboratory. This report presents the results obtained by a big group of scientists and engineers working in the field of elaboration, investigation and application of track membranes (author). 21 refs, 20 figs, 1 tab

  14. Amniotic membrane for burn trauma

    International Nuclear Information System (INIS)

    Jamaluddin Zainol; Hasim Mohammad

    1999-01-01

    Amniotic membranes are derived from human placentae at birth. They have two layers mainly the amniotic and the chorionic surfaces which are separated by a thin layer of connective tissues. The two layers are separated during procurement, the placenta and the chorionic side are discarded and the amnion membranes are then further processed. Amnion membranes are normally procured from placentae which are normally free of infections, i.e; the mothers are antenatally screened for sexually transmitted diseases or AlDs related diseases. Intrapartum the mother should not be having chorioamnionitis or jaundice. Sometimes the amniotic membranes are acquired from fresh elective caeserian sections. After processing, the amniotic membranes are packed in two layers of polypropylene and radiated with cobalt 60 at a dose of about 25 kGy. The amniotic membranes are clinically used to cover burn surfaces especially effective for superficial or partial thickness burns. The thin membranes adhered well to the trauma areas and peeled off automatically by the second week. No change of dressing were necessary during these times because of the close adherence, there were less chance of external contamination or infections of these wounds. Due to their flexibility they are very useful to cover difference contours of the human body for example the face, body, elbows or knees. However our experience revealed that amniotic membranes are not useful for third degree bums because the membranes dissolves by the enzymes present in the wounds

  15. Proton exchange membrane fuel cells

    CERN Document Server

    Qi, Zhigang

    2013-01-01

    Preface Proton Exchange Membrane Fuel CellsFuel CellsTypes of Fuel CellsAdvantages of Fuel CellsProton Exchange Membrane Fuel CellsMembraneCatalystCatalyst LayerGas Diffusion MediumMicroporous LayerMembrane Electrode AssemblyPlateSingle CellStackSystemCell Voltage Monitoring Module (CVM)Fuel Supply Module (FSM)Air Supply Module (ASM)Exhaust Management Module (EMM)Heat Management Module (HMM)Water Management Module (WMM)Internal Power Supply Module (IPM)Power Conditioning Module (PCM)Communications Module (COM)Controls Module (CM)SummaryThermodynamics and KineticsTheoretical EfficiencyVoltagePo

  16. Challenges in commercializing biomimetic membranes

    DEFF Research Database (Denmark)

    Perry, Mark; Madsen, Steen Ulrik; Jørgensen, Tine Elkjær

    2015-01-01

    The discovery of selective water channel proteins—aquaporins—has prompted growing interest in using these proteins, as the building blocks for designing new types of membranes. However, as with any other new and potentially disruptive technology, barriers for successful market entry exist. One...... of these barriers and challenges associated with introducing biomimetic aquaporin membranes. These include technical issues in membrane production and product testing. Then we discuss possible business models for introducing new technologies in general, followed by a presentation of beach-head market segments...... relevant for biomimetic aquaporin membranes....

  17. Permeability testing of biomaterial membranes

    Energy Technology Data Exchange (ETDEWEB)

    Dreesmann, L; Hajosch, R; Nuernberger, J Vaz; Schlosshauer, B [NMI Natural and Medical Sciences Institute at University Tuebingen, Markwiesenstr. 55, D-72770 Reutlingen (Germany); Ahlers, M [GELITA AG, Gammelsbacher Str. 2, D-69412 Eberbach (Germany)], E-mail: schlosshauer@nmi.de

    2008-09-01

    The permeability characteristics of biomaterials are critical parameters for a variety of implants. To analyse the permeability of membranes made from crosslinked ultrathin gelatin membranes and the transmigration of cells across the membranes, we combined three technical approaches: (1) a two-chamber-based permeability assay, (2) cell culturing with cytochemical analysis and (3) biochemical enzyme electrophoresis (zymography). Based on the diffusion of a coloured marker molecule in conjunction with photometric quantification, permeability data for a gelatin membrane were determined in the presence or absence of gelatin degrading fibroblasts. Cytochemical evaluation after cryosectioning of the membranes was used to ascertain whether fibroblasts had infiltrated the membrane inside. Zymography was used to investigate the potential release of proteases from fibroblasts, which are known to degrade collagen derivatives such as gelatin. Our data show that the diffusion equilibrium of a low molecular weight dye across the selected gelatin membrane is approached after about 6-8 h. Fibroblasts increase the permeability due to cavity formation in the membrane inside without penetrating the membrane for an extended time period (>21 days in vitro). Zymography indicates that cavity formation is most likely due to the secretion of matrix metalloproteinases. In summary, the combination of the depicted methods promises to facilitate a more rational development of biomaterials, because it provides a rapid means of determining permeability characteristics and bridges the gap between descriptive methodology and the mechanistic understanding of permeability alterations due to biological degradation.

  18. Permeability testing of biomaterial membranes

    International Nuclear Information System (INIS)

    Dreesmann, L; Hajosch, R; Nuernberger, J Vaz; Schlosshauer, B; Ahlers, M

    2008-01-01

    The permeability characteristics of biomaterials are critical parameters for a variety of implants. To analyse the permeability of membranes made from crosslinked ultrathin gelatin membranes and the transmigration of cells across the membranes, we combined three technical approaches: (1) a two-chamber-based permeability assay, (2) cell culturing with cytochemical analysis and (3) biochemical enzyme electrophoresis (zymography). Based on the diffusion of a coloured marker molecule in conjunction with photometric quantification, permeability data for a gelatin membrane were determined in the presence or absence of gelatin degrading fibroblasts. Cytochemical evaluation after cryosectioning of the membranes was used to ascertain whether fibroblasts had infiltrated the membrane inside. Zymography was used to investigate the potential release of proteases from fibroblasts, which are known to degrade collagen derivatives such as gelatin. Our data show that the diffusion equilibrium of a low molecular weight dye across the selected gelatin membrane is approached after about 6-8 h. Fibroblasts increase the permeability due to cavity formation in the membrane inside without penetrating the membrane for an extended time period (>21 days in vitro). Zymography indicates that cavity formation is most likely due to the secretion of matrix metalloproteinases. In summary, the combination of the depicted methods promises to facilitate a more rational development of biomaterials, because it provides a rapid means of determining permeability characteristics and bridges the gap between descriptive methodology and the mechanistic understanding of permeability alterations due to biological degradation

  19. Composite membrane with integral rim

    Science.gov (United States)

    Routkevitch, Dmitri; Polyakov, Oleg G

    2015-01-27

    Composite membranes that are adapted for separation, purification, filtration, analysis, reaction and sensing. The composite membranes can include a porous support structure having elongate pore channels extending through the support structure. The composite membrane also includes an active layer comprising an active layer material, where the active layer material is completely disposed within the pore channels between the surfaces of the support structure. The active layer is intimately integrated within the support structure, thus enabling great robustness, reliability, resistance to mechanical stress and thermal cycling, and high selectivity. Methods for the fabrication of composite membranes are also provided.

  20. Comparison and analysis of membrane fouling between flocculent sludge membrane bioreactor and granular sludge membrane bioreactor.

    Directory of Open Access Journals (Sweden)

    Wang Jing-Feng

    Full Text Available The goal of this study is to investigate the effect of inoculating granules on reducing membrane fouling. In order to evaluate the differences in performance between flocculent sludge and aerobic granular sludge in membrane reactors (MBRs, two reactors were run in parallel and various parameters related to membrane fouling were measured. The results indicated that specific resistance to the fouling layer was five times greater than that of mixed liquor sludge in the granular MBR. The floc sludge more easily formed a compact layer on the membrane surface, and increased membrane resistance. Specifically, the floc sludge had a higher moisture content, extracellular polymeric substances concentration, and negative surface charge. In contrast, aerobic granules could improve structural integrity and strength, which contributed to the preferable permeate performance. Therefore, inoculating aerobic granules in a MBR presents an effective method of reducing the membrane fouling associated with floc sludge the perspective of from the morphological characteristics of microbial aggregates.

  1. Degradation of Polypropylene Membranes Applied in Membrane Distillation Crystallizer

    Directory of Open Access Journals (Sweden)

    Marek Gryta

    2016-03-01

    Full Text Available The studies on the resistance to degradation of capillary polypropylene membranes assembled in a membrane crystallizer were performed. The supersaturation state of salt was achieved by evaporation of water from the NaCl saturated solutions using membrane distillation process. A high feed temperature (363 K was used in order to enhance the degradation effects and to shorten the test times. Salt crystallization was carried out by the application of batch or fluidized bed crystallizer. A significant membrane scaling was observed regardless of the method of realized crystallization. The SEM-EDS, DSC, and FTIR methods were used for investigations of polypropylene degradation. The salt crystallization onto the membrane surface accelerated polypropylene degradation. Due to a polymer degradation, the presence of carbonyl groups on the membranes’ surface was identified. Besides the changes in the chemical structure a significant mechanical damage of the membranes, mainly caused by the internal scaling, was also found. As a result, the membranes were severely damaged after 150 h of process operation. A high level of salt rejection was maintained despite damage to the external membrane surface.

  2. Effect of temperature shocks on membrane fouling in membrane bioreactors

    NARCIS (Netherlands)

    Brink, van den P.; Satpradit, O.A.; Bentem, van A.; Zwijnenburg, A.; Temmink, B.G.; Loosdrecht, M.C.M.

    2011-01-01

    Temperature is known to influence the biological performance of conventional activated sludge systems. In membrane bioreactors (MBRs), temperature not only affects the bioconversion process but is also shown to have an effect on the membrane performance. Four phenomena are generally reported to

  3. Taming Membranes : Functional Immobilization of Biological Membranes in Hydrogels

    NARCIS (Netherlands)

    Kusters, Ilja; Mukherjee, Nobina; de Jong, Menno R.; Tans, Sander; Kocer, Armagan; Driessen, Arnold J. M.

    2011-01-01

    Single molecule studies on membrane proteins embedded in their native environment are hampered by the intrinsic difficulty of immobilizing elastic and sensitive biological membranes without interfering with protein activity. Here, we present hydrogels composed of nano-scaled fibers as a generally

  4. Operation of staged membrane oxidation reactor systems

    Science.gov (United States)

    Repasky, John Michael

    2012-10-16

    A method of operating a multi-stage ion transport membrane oxidation system. The method comprises providing a multi-stage ion transport membrane oxidation system with at least a first membrane oxidation stage and a second membrane oxidation stage, operating the ion transport membrane oxidation system at operating conditions including a characteristic temperature of the first membrane oxidation stage and a characteristic temperature of the second membrane oxidation stage; and controlling the production capacity and/or the product quality by changing the characteristic temperature of the first membrane oxidation stage and/or changing the characteristic temperature of the second membrane oxidation stage.

  5. Radiation-induced damage of membranes

    International Nuclear Information System (INIS)

    Yonei, Shuji

    1977-01-01

    An outline of membranous structure was stated, and radiation-induced damage of membranes were surveyed. By irradiation, permeability of membranes, especially passive transportation mechanism, was damaged, and glycoprotein in the surface layers of cells and the surface layer structures were changed. The intramembranous damage was induced by decrease of electrophoresis of nuclear mambranes and a quantitative change of cytochrome P450 of microsomal membranes of the liver, and peroxidation of membranous lipid and SH substitute damage of membranous protein were mentioned as the mechanism of membranous damage. Recovery of membranous damage depends on radiation dose and temperature, and membranous damage participates largely in proliferation death. (tsunoda, M.)

  6. High Flux Metallic Membranes for Hydrogen Recovery and Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Buxbaum, Robert

    2010-06-30

    We made and tested over 250 new alloys for use as lower cost, higher flux hydrogen extraction membrane materials. Most of these were intermetallic, or contained significant intermetallic content, particularly based on B2 alloy compositions with at least one refractory component; B2 intermetallics resemble BCC alloys, in structure, but the atoms have relatively fixed positions, with one atom at the corners of the cube, the other at the centers. The target materals we were looking for would contain little or no expensive elements, no strongly toxic or radioactive elements, would have high flux to hydrogen, while being fabricable, brazable, and relatively immune to hydrogen embrittlement and corrosion in operation. The best combination of properties of the membrane materials we developed was, in my opinion, a Pd-coated membrane consisting of V -9 atomic % Pd. This material was relatively cheap, had 5 times the flux of Pd under the same pressure differential, was reasonably easy to fabricate and braze, and not bad in terms of embrittlement. Based on all these factors we project, about 1/3 the cost of Pd, on an area basis for a membrane designed to last 20 years, or 1/15 the cost on a flux basis. Alternatives to this membrane replaced significant fractions of the Pd with Ni and or Co. The cost for these membranes was lower, but so was the flux. We produced successful brazed products from the membrane materials, and made them into flat sheets. We tested, unsuccessfully, several means of fabricating thematerials into tubes, and eventually built a membrane reactor using a new, flat-plate design: a disc and doughnut arrangement, a design that seems well- suited to clean hydrogen production from coal. The membranes and reactor were tested successfully at Western Research. A larger equipment company (Chart Industries) produced similar results using a different flat-plate reactor design. Cost projections of the membrane are shown to be attractive.

  7. Membrane controlled anaerobic digestion

    Science.gov (United States)

    Omstead, D. R.

    In response to general shortages of energy, examination of the anaerboic digestion process as a potential source of a combustible, methane-rich fuel has intensified in recent years. It has been suggested that orgaic intermediates (such as fatty acids), produced during digestion, might also be recovered for use as chemical feedstocks. This investigation has been concerned with combining ultrafiltration separation techniques with anaerobic digestion for the development of a process in which the total production of acetic acid (the most valuable intermediate in anaerobic digestion) and methane are optimized. Enrichment cultures, able to utilize glucose as a sole carbon source, were adapted from sewage digesting cultures using conventional techniques. An ultrafiltration system was constructed and coupled to an anaerobic digester culture vessel which contained the glucose enrichment. The membrane controlled anaerobic digester appears to show promise as a means of producing high rates of both methane gas and acetic acid.

  8. Oxygen Transport Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay; T. Nithyanantham

    2006-12-31

    Ti doping on La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} (LSF) tends to increase the oxygen equilibration kinetics of LSF in lower oxygen activity environment because of the high valence state of Ti. However, the addition of Ti decreases the total conductivity because the acceptor ([Sr{prime}{sub La}]) is compensated by the donor ([Ti{sub Fe}{sup {sm_bullet}}]) which decreases the carrier concentration. The properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 1-x}Ti{sub x}O{sub 3-{delta}} (LSFT, x = 0.45) have been experimentally and theoretically investigated to elucidate (1) the dependence of oxygen occupancy and electrochemical properties on temperature and oxygen activity by thermogravimetric analysis (TGA) and (2) the electrical conductivity and carrier concentration by Seebeck coefficient and electrical measurements. In the present study, dual phase (La{sub 0.2}Sr{sub 0.8}Fe{sub 0.6}Ti{sub 0.4}O{sub 3-{delta}}/Ce{sub 0.9}Gd{sub 0.1}O{sub 2-{delta}}) membranes have been evaluated for structural properties such as hardness, fracture toughness and flexural strength. The effect of high temperature and slightly reducing atmosphere on the structural properties of the membranes was studied. The flexural strength of the membrane decreases upon exposure to slightly reducing conditions at 1000 C. The as-received and post-fractured membranes were characterized using XRD, SEM and TG-DTA to understand the fracture mechanisms. Changes in structural properties of the composite were sought to be correlated with the physiochemical features of the two-phases. We have reviewed the electrical conductivity data and stoichiometry data for La{sub 0.2}Sr{sub 0.8}Cr{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} some of which was reported previously. Electrical conductivity data for La{sub 0.2}Sr{sub 0.8}Cr{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCrF) were obtained in the temperature range, 752 {approx} 1055 C and in the pO{sub 2} range, 10{sup -18} {approx} 0.5 atm. The slope of the plot of log {sigma} vs

  9. Oxygen Transport Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay; T. Nithyanantham

    2006-06-30

    A non-agglomerated and nanocrystalline-sized powder was successfully produced using ethylene glycol nitrate methods. The LSFT powder prepared using this method exhibits well dispersed and nano-sized particles about 100-200 nm. The density of LSFT sintered at 1300 C was about 90% of the theoretical density at which is 100 C less than that of the previous LSFT which was sintered at 1400 C. The sample sintered at 1400 C exhibited the evidence of a liquid phase at the grain boundaries and 2nd phase formation which probably caused low mechanical stability. The electrical conductivity and Seebeck coefficient were measured as a function of temperature. The LSFT-CGO specimens were cut from the as sintered bars and used for the evaluation of Mechanical Properties after polishing. The effect of strain rate on the flexural strength of the LSFT-CGO test specimens was studied. Three strain rates 6, 60 and 600 {micro}m/ min were chosen for this study. It is observed from the results that with increasing cross head speed the membrane takes higher loads to fail. A reduction in the strength of the membrane was observed at 1000 C in N{sub 2}. Two different routes were investigated to synthesis GDC using either formate or carbonate precursors. The precursor and CGO particle morphologies were examined by scanning electron microscopy. The thermal decomposition behaviors of Ce(Gd)(HCOO){sub 3} and Ce(Gd)(CO{sub 3})(OH) were determined by thermogravimetric analysis (TGA) at a rate of 3 C/min in air. The X-ray powder diffraction patterns of the precursor and CGO were collected and nitrogen adsorption isotherms were measured. Conductivity measurements were made by AC impedance spectroscopy on sintered disks in air using platinum electrodes.

  10. Oxygen Transport Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay; N. Nagabhushana

    2003-08-07

    In the present quarter, experiments are presented on ceramic/metal interactions of Zirconia/ Ni-B-Si system and with a thin Ti coating deposited on zirconia surface. Existing facilities were modified for evaluation of environmental assisted slow crack growth and creep in flexural mode. Processing of perovskites of LSC, LSF and LSCF composition were continued for evaluation of mechanical properties as a function of environment. These studies in parallel to those on the LSFCO composition is expect to yield important information on questions such as the role of cation segregation and the stability of the perovskite structure on crack initiation vs. crack growth. Studies have been continued on the La{sub 1-x}Sr{sub x}FeO{sub 3-d} composition using neutron diffraction and TGA studies. A transition from p-type to n-type of conductor was observed at relative low pO{sub 2}, at which the majority carriers changed from the holes to electrons because of the valence state decreases in Fe due to the further loss of oxygen. Investigation on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane transport. Data obtained at 850 C show that the stoichiometry in La{sub 0.2}Sr{sub 0.8}Fe{sub 0.8}Cr{sub 0.2}O{sub 3-x} vary from {approx}2.85 to 2.6 over the pressure range studied. From the stoichiometry a lower limit of 2.6 corresponding to the reduction of all Fe{sup 4+} to Fe{sup 3+} and no reduction of Cr{sup 3+} is expected.

  11. Electro-catalytic membrane reactors and the development of bipolar membrane technology

    NARCIS (Netherlands)

    Balster, J.H.; Stamatialis, Dimitrios; Wessling, Matthias

    2004-01-01

    Membrane reactors are currently under extensive research and development. Hardly any concept, however, is realized yet in practice. Frequently, forgotten as membrane reactors are electro-catalytic membrane reactors where electrodes perform chemical conversations and membranes separate the locations

  12. Biogenesis of plasma membrane cholesterol

    International Nuclear Information System (INIS)

    Lange, Y.

    1986-01-01

    A striking feature of the molecular organization of eukaryotic cells is the singular enrichment of their plasma membranes in sterols. The authors studies are directed at elucidating the mechanisms underlying this inhomogeneous disposition. Cholesterol oxidase catalyzes the oxidation of plasma membrane cholesterol in intact cells, leaving intracellular cholesterol pools untouched. With this technique, the plasma membrane was shown to contain 95% of the unesterified cholesterol of cultured human fibroblasts. Cholesterol synthesized from [ 3 H] acetate moved to the plasma membrane with a half-time of 1 h at 37 0 C. They used equilibrium gradient centrifugation of homogenates of biosynthetically labeled, cholesterol oxidase treated cells to examine the distribution of newly synthesized sterols among intracellular pools. Surprisingly, lanosterol, a major precursor of cholesterol, and intracellular cholesterol both peaked at much lower buoyant density than did 3-hydroxy-3-methylglutaryl-CoA reductase. This suggests that cholesterol biosynthesis is not taken to completion in the endoplasmic reticulum. The cholesterol in the buoyant fraction eventually moved to the plasma membrane. Digitonin treatment increased the density of the newly synthesized cholesterol fractions, indicating that nascent cholesterol in transit is associated with cholesterol-rich membranes. The authors are testing the hypothesis that the pathway of cholesterol biosynthesis is spatially organized in various intracellular membranes such that the sequence of biosynthetic steps both concentrates the sterol and conveys it to the plasma membrane

  13. Modelling of proteins in membranes

    DEFF Research Database (Denmark)

    Sperotto, Maria Maddalena; May, S.; Baumgaertner, A.

    2006-01-01

    This review describes some recent theories and simulations of mesoscopic and microscopic models of lipid membranes with embedded or attached proteins. We summarize results supporting our understanding of phenomena for which the activities of proteins in membranes are expected to be significantly...

  14. Fabrication of green polymeric membranes

    KAUST Repository

    Kim, Dooli

    2017-06-16

    Provided herein are methods of fabricating membranes using polymers with functionalized groups such as sulfone (e.g., PSf and PES), ether (e.g., PES), acrylonitrile (e.g., PAN), fluoride(e.g., pvdf and other fluoropolymers), and imide (e.g., extem) and ionic liquids. Also provided are membranes made by the provided methods.

  15. Inorganic membranes for pervaporation technology

    NARCIS (Netherlands)

    Sekulic, J.; Luiten-Olieman, Maria W.J.; Luiten, M.W.J.; ten Elshof, Johan E.; Benes, Nieck Edwin; Keizer, Klaas

    2002-01-01

    The aim of this work is the development of inorganic membranes that will enable broad application of pervaporation/vapour permeation technology in the chemical industry. This can be achieved by improvement of the existing microporous membranes and the development of new types with enhanced

  16. Mathematical modelling of membrane separation

    DEFF Research Database (Denmark)

    Vinther, Frank

    This thesis concerns mathematical modelling of membrane separation. The thesis consists of introductory theory on membrane separation, equations of motion, and properties of dextran, which will be the solute species throughout the thesis. Furthermore, the thesis consist of three separate mathemat......This thesis concerns mathematical modelling of membrane separation. The thesis consists of introductory theory on membrane separation, equations of motion, and properties of dextran, which will be the solute species throughout the thesis. Furthermore, the thesis consist of three separate...... mathematical models, each with a different approach to membrane separation. The first model is a statistical model investigating the interplay between solute shape and the probability of entering the membrane. More specific the transition of solute particles from being spherical to becoming more elongated...... and the rejection coefficient. The second model is a stationary model for the flux of solvent and solute in a hollow fibre membrane. In the model we solve the time independent equations for transport of solvent and solute within the hollow fibre. Furthermore, the flux of solute and solvent through the membrane...

  17. Membranes and Films from Polymers.

    Science.gov (United States)

    Blumberg, Avrom A.

    1986-01-01

    Provides background information on polymeric films and membranes including production methods, special industrial and medical applications, laboratory preparation, and an experimental investigation of a porous cellulose acetate membrane. Presents a demonstration to distinguish between high- and low-density polyethylene. (JM)

  18. Nitrocellulose Membrane: The New Canvas.

    Science.gov (United States)

    Kurien, Jasmin R; Kurien, Bianca A

    2015-01-01

    The use of nitrocellulose membranes for invisible ink-messaging or marking for orientation purposes has been carried out with diluted alkaline phosphatase, followed by development with nitro blue tetrazolium/5-bromo-4-chloro-3-indolyl phosphate and chemiluminescence detection systems. Here, we show that nitrocellulose membrane can serve as a canvas for art using alkaline phosphatase and NBT/BCIP detection method.

  19. Gas separation membranes current status

    International Nuclear Information System (INIS)

    Puri, S.P.

    1996-01-01

    Membrane-based gas separation systems are now widely accepted and employed as unit operation in industrial gas, chemical and allied industries. Following their successful commercialization in the late Seventies to recover hydrogen from ammonia purge gas streams, membrane-based systems have gained acceptance in a wide variety of applications

  20. Membranes for Enhanced Emulsification Processes

    NARCIS (Netherlands)

    Güell, Carme; Ferrando, Montse; Schroen, C.G.P.H.

    2016-01-01

    The use of membrane technology for the production of single and double emulsions has been proven feasible for a wide range of systems. The low energy requirements and mild process conditions (shear stress and temperature) of membrane emulsification (ME) compared to conventional processes makes it of

  1. Hydrogen Selective Exfoliated Zeolite Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Tsapatsis, Michael [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Daoutidis, Prodromos [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Elyassi, Bahman [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Lima, Fernando [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Iyer, Aparna [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Agrawal, Kumar [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Sabnis, Sanket [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science

    2015-04-06

    The objective of this project was to develop and evaluate an innovative membrane technology at process conditions that would be representative of Integrated Gasification Combined Cycle (IGCC) advanced power generation with pre-combustion capture of carbon dioxide (CO2). This research focused on hydrogen (H2)-selective zeolite membranes that could be utilized to separate conditioned syngas into H2-rich and CO2-rich components. Both experiments and process design and optimization calculations were performed to evaluate the concept of ultra-thin membranes made from zeolites nanosheets. In this work, efforts in the laboratory were made to tackle two fundamental challenges in application of zeolite membranes in harsh industrial environments, namely, membrane thickness and membrane stability. Conventional zeolite membranes have thicknesses in the micron range, limiting their performance. In this research, we developed a method for fabrication of ultimately thin zeolite membranes based on zeolite nanosheets. A range of layered zeolites (MWW, RWR, NSI structure types) suitable for hydrogen separation was successfully exfoliated to their constituent nanosheets. Further, membranes were made from one of these zeolites, MWW, to demonstrate the potential of this group of materials. Moreover, long-term steam stability of these zeolites (up to 6 months) was investigated in high concentrations of steam (35 mol% and 95 mole%), high pressure (10 barg), and high temperatures (350 °C and 600 °C) relevant to conditions of water-gas-shift and steam methane reforming reactions. It was found that certain nanosheets are stable, and that stability depends on the concentration of structural defects. Additionally, models that represent a water-gas-shift (WGS) membrane reactor equipped with the zeolite membrane were developed for systems studies. These studies had the aim of analyzing the effect of the membrane reactor integration into IGCC plants

  2. Staged membrane oxidation reactor system

    Science.gov (United States)

    Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

    2012-09-11

    Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

  3. Drug-model membrane interactions

    International Nuclear Information System (INIS)

    Deniz, Usha K.

    1994-01-01

    In the present day world, drugs play a very important role in medicine and it is necessary to understand their mode of action at the molecular level, in order to optimise their use. Studies of drug-biomembrane interactions are essential for gaining such as understanding. However, it would be prohibitively difficult to carry out such studies, since biomembranes are highly complex systems. Hence, model membranes (made up of these lipids which are important components of biomembranes) of varying degrees of complexity are used to investigate drug-membrane interactions. Bio- as well as model-membranes undergo a chain melting transition when heated, the chains being in a disordered state above the transition point, T CM . This transition is of physiological importance since biomembranes select their components such that T CM is less than the ambient temperature but not very much so, so that membrane flexibility is ensured and porosity, avoided. The influence of drugs on the transition gives valuable clues about various parameters such as the location of the drug in the membrane. Deep insights into drug-membrane interactions are obtained by observing the effect of drugs on membrane structure and the mobilities of the various groups in lipids, near T CM . Investigation of such changes have been carried out with several drugs, using techniques such as DSC, XRD and NMR. The results indicate that the drug-membrane interaction not only depends on the nature of drug and lipids but also on the form of the model membrane - stacked bilayer or vesicles. The light that these results shed on the nature of drug-membrane interactions is discussed. (author). 13 refs., 13 figs., 1 tab

  4. Nanoporous Membrane Technologies for Pathogen Collection, Separation, and Detection

    National Research Council Canada - National Science Library

    Lee, Sang W; Shang, Hao; Lee, Gil U; Griffin, Matthew T; Fulton, Jack

    2003-01-01

    Partial contents: Nanoporous Membranes, Membrane Chemistries, Characterization of Membrane Chemistries,Protein Fouling, Collector,Gas and Liquid Permeabilities, Membrane Permeabilities in the Presence of Water...

  5. Membranes and theoretical modeling of membrane distillation: a review.

    Science.gov (United States)

    Khayet, Mohamed

    2011-05-11

    Membrane distillation (MD) is one of the non-isothermal membrane separation processes used in various applications such desalination, environmental/waste cleanup, food, etc. It is known since 1963 and is still being developed at laboratory stage for different purposes and not fully implemented in industry. An abrupt increase in the number of papers on MD membrane engineering (i.e. design, fabrication and testing in MD) is seen since only 6 years ago. The present paper offers a comprehensive MD state-of-the-art review covering a wide range of commercial membranes, MD membrane engineering, their MD performance, transport mechanisms, experimental and theoretical modeling of different MD configurations as well as recent developments in MD. Improved MD membranes with specific morphology, micro- and nano-structures are highly demanded. Membranes with different pore sizes, porosities, thicknesses and materials as well as novel structures are required in order to carry out systematic MD studies for better understanding mass transport in different MD configurations, thereby improving the MD performance and looking for MD industrialization. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Electrospun superhydrophobic membranes with unique structures for membrane distillation.

    Science.gov (United States)

    Liao, Yuan; Loh, Chun-Heng; Wang, Rong; Fane, Anthony G

    2014-09-24

    With modest temperature demand, low operating pressure, and high solute rejection, membrane distillation (MD) is an attractive option for desalination, waste treatment, and food and pharmaceutical processing. However, large-scale practical applications of MD are still hindered by the absence of effective membranes with high hydrophobicity, high porosity, and adequate mechanical strength, which are important properties for MD permeation fluxes, stable long-term performance, and effective packing in modules without damage. This study describes novel design strategies for highly robust superhydrophobic dual-layer membranes for MD via electrospinning. One of the newly developed membranes comprises a durable and ultrathin 3-dimensional (3D) superhydrophobic skin and porous nanofibrous support whereas another was fabricated by electrospinning 3D superhydrophobic layers on a nonwoven support. These membranes exhibit superhydrophobicity toward distilled water, salty water, oil-in-water emulsion, and beverages, which enables them to be used not only for desalination but also for other processes. The superhydrophobic dual-layer membrane #3S-N with nanofibrous support has a competitive permeation flux of 24.6 ± 1.2 kg m(-2) h(-1) in MD (feed and permeate temperate were set as 333 and 293 K, respectively) due to the higher porosity of the nanofibrous scaffold. Meanwhile, the membranes with the nonwoven support exhibit greater mechanical strength due to this support combined with better long-term performance because of the thicker 3D superhydrophobic layers. The morphology, pore size, porosity, mechanical properties, and liquid enter pressure of water of these superhydrophobic composite membranes with two different structures are reported and compared with commercial polyvinylidene fluoride membranes.

  7. Universal Behavior of Membranes with Sterols

    DEFF Research Database (Denmark)

    Henriksen, Jonas Rosager; Rowat, Amy C.; Brief, E.

    2006-01-01

    ) is obtained from deuterium nuclear magnetic resonance. We compare these results, along with data for membrane-bending rigidity, to explore the relationship between membrane hydrophobic thickness and elastic properties. Together, such diverse approaches demonstrate that membrane properties are affected...

  8. Membrane species mobility under in-lipid-membrane forced convection.

    Science.gov (United States)

    Hu, Shu-Kai; Huang, Ling-Ting; Chao, Ling

    2016-08-17

    Processing and managing cell membrane proteins for characterization while maintaining their intact structure is challenging. Hydrodynamic flow has been used to transport membrane species in supported lipid bilayers (SLBs) where the hydrophobic cores of the membrane species can be protected during processing. However, the forced convection mechanism of species embedded in lipid bilayers is still unclear. Developing a controlled SLB platform with a practical model to predict the membrane species mobility in the platform under in-lipid-membrane forced convection is imperative to ensure the practical applicability of SLBs in processing and managing membrane species with various geometrical properties. The mobility of membrane species is affected by the driving force from the aqueous environment in addition to the frictions from the lipid bilayer, in which both lipid leaflets may exhibit different speeds relative to that of the moving species. In this study, we developed a model, based on the applied driving force and the possible frictional resistances that the membrane species encounter, to predict how the mobility under in-lipid-membrane forced convection is influenced by the sizes of the species' hydrophilic portion in the aqueous environment and the hydrophobic portion embedded in the membrane. In addition, we used a microfluidic device for controlling the flow to arrange the lipid membrane and the tested membrane species in the desirable locations in order to obtain a SLB platform which can provide clear mobility responses of the species without disturbance from the species dispersion effect. The model predictions were consistent with the experimental observations, with the sliding friction coefficient between the upper leaflet and the hydrophilic portion of the species as the only regressed parameter. The result suggests that not only the lateral drag frictions from the lipid layers but also the sliding frictions between the species and the lipid layer planes

  9. Artificial membranes for membrane protein purification, functionality and structure studies.

    Science.gov (United States)

    Parmar, Mayuriben J; Lousa, Carine De Marcos; Muench, Stephen P; Goldman, Adrian; Postis, Vincent L G

    2016-06-15

    Membrane proteins represent one of the most important targets for pharmaceutical companies. Unfortunately, technical limitations have long been a major hindrance in our understanding of the function and structure of such proteins. Recent years have seen the refinement of classical approaches and the emergence of new technologies that have resulted in a significant step forward in the field of membrane protein research. This review summarizes some of the current techniques used for studying membrane proteins, with overall advantages and drawbacks for each method. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

  10. Oxygen Transport Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

    2004-10-01

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, Moessbauer spectroscopy was used to study the local environmentals of LSFT with various level of oxygen deficiency. Ionic valence state, magnetic interaction and influence of Ti on superexchange are discussed Stable crack growth studies on Dense OTM bars provided by Praxair were done at elevated temperature, pressure and elevated conditions. Post-fracture X-ray data of the OTM fractured at 1000 C in environment were refined by FullProf code and results indicate a distortion of the parent cubic perovskite to orthorhombic structure with reduced symmetry. TGA-DTA studies on the post-fracture samples also indicated residual effect arising from the thermal and stress history of the samples. An electrochemical cell has been designed and built for measurements of the Seebeck coefficient as a function of temperature and pressure. The initial measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} are reported. Neutron diffraction measurements of the same composition are in agreement with both the stoichiometry and the kinetic behavior observed in coulometric titration measurements. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The COCO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

  11. Cell invasion through basement membrane

    Science.gov (United States)

    Morrissey, Meghan A; Hagedorn, Elliott J; Sherwood, David R

    2013-01-01

    Cell invasion through basement membrane is an essential part of normal development and physiology, and occurs during the pathological progression of human inflammatory diseases and cancer. F-actin-rich membrane protrusions, called invadopodia, have been hypothesized to be the “drill bits” of invasive cells, mediating invasion through the dense, highly cross-linked basement membrane matrix. Though studied in vitro for over 30 y, invadopodia function in vivo has remained elusive. We have recently discovered that invadopodia breach basement membrane during anchor cell invasion in C. elegans, a genetically and visually tractable in vivo invasion event. Further, we found that the netrin receptor DCC localizes to the initial site of basement membrane breach and directs invasion through a single gap in the matrix. In this commentary, we examine how the dynamics and structure of AC-invadopodia compare with in vitro invadopodia and how the netrin receptor guides invasion through a single basement membrane breach. We end with a discussion of our surprising result that the anchor cell pushes the basement membrane aside, instead of completely dissolving it through proteolysis, and provide some ideas for how proteases and physical displacement may work together to ensure efficient and robust invasion. PMID:24778942

  12. Membrane bioreactors: present and prospects.

    Science.gov (United States)

    Chang, H N; Furusaki, S

    1991-01-01

    Membrane bioreactors have a very handy in-situ separation capability lacking in other types of bioreactors. Combining various functions of membrane separations and biocatalyst characteristics of enzymes, microbial cells, organelles, animal and plant tissues can generate quite a number of membrane bioreactor systems. The cell retaining property of membranes and selective removal of inhibitory byproducts makes high cell density culture possible and utilizes enzyme catalytic activity better, which leads to high productivity of bioreactors. Enzyme reactions utilizing cofactors and hydrolysis of macromolecules are advantageous in membrane bioreactors. Anaerobic cell culture may be efficiently carried out in membrane cell recycle systems, while aerobic cultures work well in dual hollow fiber reactors. Animal and plant cells have much a better chance of success in membrane reactors because of the protective environment of the reactor and the small oxygen uptake rate of these cells. Industrial use of these reactors are still in its infancy and limited to enzyme and animal tissue culture, but applications will expand as existing problems are resolved.

  13. Membrane manufacture for peptide separations

    KAUST Repository

    Kim, Dooli

    2016-06-07

    Nanostructured polymeric membranes are key tools in biomedical applications such as hemodialysis, protein separations, in the food industry, and drinking water supply from seawater. Despite of the success in different separation processes, membrane manufacture itself is at risk, since the most used solvents are about to be banned in many countries due to environmental and health issues. We propose for the first time the preparation of polyethersulfone membranes based on dissolution in the ionic liquid 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM]DEP). We obtained a series of membranes tailored for separation of solutes with molecular weight of 30, 5, 1.3, and 1.25 kg mol-1 with respective water permeances of 140, 65, 30 and 20 Lm-2h-1bar-1. We demonstrate their superior efficiency in the separation of complex mixtures of peptides with molecular weights in the range of 800 to 3500 gmol-1. Furthermore, the thermodynamics and kinetics of phase separation leading to the pore formation in the membranes were investigated. The rheology of the solutions and the morphology of the prepared membranes were examed and compared to those of polyethersulfone in organic solvents currently used for membrane manufacture.

  14. Gas Separations using Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Paul KT Liu

    2005-01-13

    This project has been oriented toward the development of a commercially viable ceramic membrane for high temperature gas separations. A technically and commercially viable high temperature gas separation membrane and process has been developed under this project. The lab and field tests have demonstrated the operational stability, both performance and material, of the gas separation thin film, deposited upon the ceramic membrane developed. This performance reliability is built upon the ceramic membrane developed under this project as a substrate for elevated temperature operation. A comprehensive product development approach has been taken to produce an economically viable ceramic substrate, gas selective thin film and the module required to house the innovative membranes for the elevated temperature operation. Field tests have been performed to demonstrate the technical and commercial viability for (i) energy and water recovery from boiler flue gases, and (ii) hydrogen recovery from refinery waste streams using the membrane/module product developed under this project. Active commercializations effort teaming with key industrial OEMs and end users is currently underway for these applications. In addition, the gas separation membrane developed under this project has demonstrated its economical viability for the CO2 removal from subquality natural gas and landfill gas, although performance stability at the elevated temperature remains to be confirmed in the field.

  15. Emergency department revisits for pediatric acute asthma exacerbations: association of factors identified in an emergency department asthma tracking system.

    Science.gov (United States)

    Walsh-Kelly, Christine M; Kelly, Kevin J; Drendel, Amy L; Grabowski, Laura; Kuhn, Evelyn M

    2008-08-01

    To identify clinical variables associated with a greater likelihood of emergency department (ED) revisit for acute asthma within 7 days after an initial ED visit for acute asthma exacerbation. Cross-sectional study of subjects from a prospectively enrolled cohort of children aged 0 to 18 years with physician-diagnosed asthma in the ED Allies Tracking System. Demographics and data on quality of life, health care utilization, environmental factors, chronic asthma severity, and ED management were collected. Emergency department revisits for acute asthma within 7 days of a prior visit resulting in discharge were compared with those without a revisit, using chi2 and t tests and logistic regression. Four thousand two hundred twenty-eight ED asthma visits were enrolled; 3276 visits resulted in discharge. Persistent asthma was identified in 66% of visits. Emergency department revisits within 7 days of a prior visit occurred following 133 (4.1%) visits. There were no significant differences in environmental factors or ED management between visits with and without an ED revisit. In univariate analysis factors associated with a greater revisit likelihood included age younger than 2 years, black race or Hispanic ethnicity, persistent asthma, public insurance, lower quality of life, and greater health care utilization in the prior 12 months. Variables independently significant (P children younger than 2 years or with persistent asthma or lower asthma quality-of-life scores are at greater risk for ED revisits after acute ED asthma care.

  16. THE INFLUENCE OF DESTINATION IMAGE AND TOURIST SATISFACTION TOWARD REVISIT INTENTION OF SETU BABAKAN BETAWI CULTURAL VILLAGE

    Directory of Open Access Journals (Sweden)

    Setyo Ferry Wibowo

    2016-04-01

    Full Text Available The purpose of this research are: 1 To find out the description of destination image, tourist satisfaction, and revisit intention of Betawi cultural village Setu Babakan, 2 test empirically the influence of destination image toward revisit intention of Betawi cultural village Setu Babakan, 3 test empirically the influence of tourist satisfaction toward revisit intention of Betawi cultural village Setu Babakan, 4 test empirically the influence of destination image toward revisit intention of Betawi cultural village Setu Babakan. The object of this research was 200 respondents who have ever visit to Betawi cultural village Setu Babakan at one time. The results of descriptive test explained that the destination image provided is good according to the tourist, so that the tourist is satisfied and want to revisit intention of Betawi cultural village Setu Babakan. The hypothesis test shows: 1 the influence of destination image toward revisit intention by -30%, 2 the influence of tourist satisfaction toward revisit intention by 118%, 3 the influence of destination image toward tourist satisfaction by 92%.

  17. The Effects of Korean Medical Service Quality and Satisfaction on Revisit Intention of the United Arab Emirates Government Sponsored Patients.

    Science.gov (United States)

    Lee, Seoyoung; Kim, Eun-Kyung

    2017-06-01

    The purpose of this study was to investigate medical service quality, satisfaction and to examine factors influencing hospital revisit intention of the United Arab Emirates government sponsored patients in Korea. A total of 152 UAE government sponsored patients who visited Korean hospitals participated in the questionnaire survey from August to November 2016. Stepwise multiple regression was used to identify the factors that affected the revisit intention of the participants. The mean scores of medical service quality, satisfaction, and revisit intention were 5.72 out of 7, 88.88 out of 100, 4.59 out of 5, respectively. Medical service quality and satisfaction, Medical service quality and revisit intention, satisfaction and revisit intention were positively correlated. Medical service of physician, visiting routes and responsiveness of medical service quality explained about 23.8% of revisit intention. There are needs for physicians to communicate with patients while ensuring sufficient consultation time based on excellent medical skills and nurses to respond immediately for the patients' needs through an empathic encounter in order to improve medical service quality and patient satisfaction so that to increase the revisit intention of the United Arab Emirates government sponsored patients. Further, it is necessary for the hospitals to have support plans for providing country specialized services in consideration of the UAE culture to ensure that physicians' and nurses' competencies are not undervalued by non-medical service elements such as interpreters and meals. Copyright © 2017. Published by Elsevier B.V.

  18. Ultrastructure of Reissner's membrane in the rabbit

    DEFF Research Database (Denmark)

    Qvortrup, K.; Rostgaard, Jørgen; Bretlau, P.

    1994-01-01

    Anatomy, Reissner's membrane, electron microscopy, tubulocisternal endoplasmic reticulum, subsurface cisterns, rabbit......Anatomy, Reissner's membrane, electron microscopy, tubulocisternal endoplasmic reticulum, subsurface cisterns, rabbit...

  19. Isolation of plasma membrane-associated membranes from rat liver.

    Science.gov (United States)

    Suski, Jan M; Lebiedzinska, Magdalena; Wojtala, Aleksandra; Duszynski, Jerzy; Giorgi, Carlotta; Pinton, Paolo; Wieckowski, Mariusz R

    2014-02-01

    Dynamic interplay between intracellular organelles requires a particular functional apposition of membrane structures. The organelles involved come into close contact, but do not fuse, thereby giving rise to notable microdomains; these microdomains allow rapid communication between the organelles. Plasma membrane-associated membranes (PAMs), which are microdomains of the plasma membrane (PM) interacting with the endoplasmic reticulum (ER) and mitochondria, are dynamic structures that mediate transport of proteins, lipids, ions and metabolites. These structures have gained much interest lately owing to their roles in many crucial cellular processes. Here we provide an optimized protocol for the isolation of PAM, PM and ER fractions from rat liver that is based on a series of differential centrifugations, followed by the fractionation of crude PM on a discontinuous sucrose gradient. The procedure requires ∼8-10 h, and it can be easily modified and adapted to other tissues and cell types.

  20. Diffusion of Integral Membrane Proteins in Protein-Rich Membranes

    DEFF Research Database (Denmark)

    Javanainen, Matti; Martinez-Seara, Hector; Metzler, Ralf

    2017-01-01

    -like dependence D ∝ 1/R. We propose that this 1/R law mainly arises due to geometrical factors: smaller proteins are able to avoid confinement effects much better than their larger counterparts. The results highlight that the lateral dynamics in the crowded setting found in native membranes is radically different......The lateral diffusion of embedded proteins along lipid membranes in protein-poor conditions has been successfully described in terms of the Saffman-Delbrück (SD) model, which predicts that the protein diffusion coefficient D is weakly dependent on its radius R as D ∝ ln(1/R). However, instead...... of being protein-poor, native cell membranes are extremely crowded with proteins. On the basis of extensive molecular simulations, we here demonstrate that protein crowding of the membrane at physiological levels leads to deviations from the SD relation and to the emergence of a stronger Stokes...

  1. Effect of membrane polymeric materials on relationship between surface pore size and membrane fouling in membrane bioreactors

    Science.gov (United States)

    Miyoshi, Taro; Yuasa, Kotaku; Ishigami, Toru; Rajabzadeh, Saeid; Kamio, Eiji; Ohmukai, Yoshikage; Saeki, Daisuke; Ni, Jinren; Matsuyama, Hideto

    2015-03-01

    We investigated the effect of different membrane polymeric materials on the relationship between membrane pore size and development of membrane fouling in a membrane bioreactor (MBR). Membranes with different pore sizes were prepared using three different polymeric materials, cellulose acetate butyrate (CAB), polyvinyl butyral (PVB), and polyvinylidene fluoride (PVDF), and the development of membrane fouling in each membrane was evaluated by batch filtration tests using a mixed liquor suspension obtained from a laboratory-scale MBR. The results revealed that the optimal membrane pore size to mitigate membrane fouling differed depending on membrane polymeric material. For PVDF membranes, the degree of membrane fouling decreased as membrane pore size increased. In contrast, CAB membranes with smaller pores had less fouling propensity than those with larger ones. Such difference can be attributed to the difference in major membrane foulants in each membrane; in PVDF, they were small colloids or dissolved organics in which proteins are abundant, and in CAB, microbial flocs. The results obtained in this study strongly suggested that optimum operating conditions of MBRs differ depending on the characteristics of the used membrane.

  2. Development of silica RO membranes

    International Nuclear Information System (INIS)

    Ikeda, Ayumi; Kawamoto, Takashi; Matsuyama, Emi; Utsumi, Keisuke; Nomura, Mikihiro; Sugimoto, Masaki; Yoshikawa, Masato

    2012-01-01

    Silica based membranes have been developed by using a counter diffusion CVD method. Effects of alkyl groups in the silica precursors and deposition temperatures had investigated in order to control pore sizes of the silica membranes. In this study, this type of a silica membrane was applied for RO separation. Effects of silica sources, deposition temperatures and post treatments had been investigated. Tetramethoxysilane (TMOS), Ethyltrimethoxysilane (ETMOS) and Phenyltrimethoxysilane (PhTMOS) were used as silica precursors. A counter diffusion CVD method was carried out for 90 min at 270 - 600degC on γ-alumina capillary substrates (effective length: 50 mm, φ: 4 nm: NOK Co.). O 3 or O 2 was introduced into the inside of the substrate at the O 2 rate of 0.2 L min -1 . Ion beam irradiation was carried out for a post treatment using Os at 490 MeV for 1.0 x 10 10 ions cm -2 or 3.0 x 10 10 ions cm -2 . Single gas permeance was measured by using H 2 , N 2 and SF 6 . RO tests were employed at 3.0 or 5.4 MPa for 100 mg L -1 of feed NaCl solution. First, effects of the silica sources were investigated. The total fluxes increased by increasing N 2 permeance through the silica membrane deposited by ETMOS. The maximum NaCl rejection was 28.2% at 12.2 kg m -2 h -1 of the total flux through the membrane deposited at 270degC. N 2 permeance was 9.6 x 10 -9 mol m -2 s -1 Pa -1 . While, total fluxes through the membrane deposited by using PhTMOS were smaller than those through the ETMOS membranes. The phenyl groups for the PhTMOS membrane must be important for the hydrophobic properties through the membrane. Next, effects of ion beam irradiation were tested for the TMOS membranes. Water is difficult to permeate through the TMOS membranes due to the low N 2 permeance through the membrane (3.1 x 10 -11 mol m -2 s -1 Pa -1 ). N 2 permeance increased to 7.3 x 10 -9 mol m -2 s -1 Pa -1 by the irradiation. Irradiation amounts had little effects on N 2 permeance. However, NaCl rejections

  3. Membrane fluidity in the presence of membrane-binding peptides

    Science.gov (United States)

    Burrola Gabilondo, Beatriz; Losert, Wolfgang; Randazzo, Paul

    2009-03-01

    Arf proteins are GTP-ases that participate in vesicle trafficking inside cells. They are able to interact with membranes through their N-terminus when they are bound to GTP, and they detach from the membrane when GTP is hydrolyzed. The N-terminus of Arf1 (amino acids 2-17) folds into an amphipathic helix that can insert into lipid bilayers. Arf1 is also myristoylated; it has myristic acid, a 14-carbon fatty acid `tail', attached to it. We set out to test the hypothesis that the binding of the myristoylated N-terminus of Arf1 to lipid membranes changes the mechanical properties of the membrane, in ways that myristic acid alone or amphipathic peptides alone do not. We use three reporter molecules embedded in vesicles, whose fluorescence emission spectrum depends on the properties of the environment in which they are found, to measure three distinct aspects of membrane fluidity: Bispyrene is sensitive to lateral motion along the membrane, Prodan's emission gives a measure of the packing of the head groups, and DPH polarization reflects the packing of the hydrophobic tails. We will present effects found for four molecules (myristic acid, myristoylated and non-myristoylated N-terminus of Arf1, and the ALPS domain of KES) in a concentration-dependent manner, and discuss the importance of these results in the vesicle-trafficking picture.

  4. Vacuum membrane distillation of liquid desiccants Utilizing Hollow Fiber Membranes

    KAUST Repository

    Lefers, Ryan

    2018-01-31

    This paper documents the testing of a vacuum membrane distillation system intended for use with liquid desiccants. Liquid desiccants offer the possibility for low-energy, ambient temperature dehumidification. Effective desalination and purification of diluted desiccants outputs two important products: a concentrated desiccant for reuse in dehumidification and fresh water. In this study, vacuum membrane distillation was used in the laboratory to purify diluted liquid desiccants. Calcium chloride and magnesium chloride were the desiccants selected for testing. Desiccant solutions were pumped through the lumens of poly(vinylidene fluoride) (PVDF) hollow fiber membranes at varying feed inlet temperatures, solution velocity rates and vacuum set points during membrane distillation. An average flux of 8 kg m-2 h-1 was obtained using 30 wt% magnesium chloride solution at a temperature of 50 °C while applying vacuum to achieve 25 mbar absolute pressure on the air side of the membrane. The results are promising for the development of a full-scale vacuum membrane distillation process for desiccant solution regeneration and fresh water recovery. In addition, the recovered condensate was of sufficient quality for use in agricultural irrigation or drinking water.

  5. The Role of Ion Exchange Membranes in Membrane Capacitive Deionisation.

    Science.gov (United States)

    Hassanvand, Armineh; Wei, Kajia; Talebi, Sahar; Chen, George Q; Kentish, Sandra E

    2017-09-14

    Ion-exchange membranes (IEMs) are unique in combining the electrochemical properties of ion exchange resins and the permeability of a membrane. They are being used widely to treat industrial effluents, and in seawater and brackish water desalination. Membrane Capacitive Deionisation (MCDI) is an emerging, energy efficient technology for brackish water desalination in which these ion-exchange membranes act as selective gates allowing the transport of counter-ions toward carbon electrodes. This article provides a summary of recent developments in the preparation, characterization, and performance of ion exchange membranes in the MCDI field. In some parts of this review, the most relevant literature in the area of electrodialysis (ED) is also discussed to better elucidate the role of the ion exchange membranes. We conclude that more work is required to better define the desalination performance of the proposed novel materials and cell designs for MCDI in treating a wide range of feed waters. The extent of fouling, the development of cleaning strategies, and further techno-economic studies, will add value to this emerging technique.

  6. Omniphobic Hollow-Fiber Membranes for Vacuum Membrane Distillation.

    Science.gov (United States)

    Lu, Kang Jia; Zuo, Jian; Chang, Jian; Kuan, Hong Nan; Chung, Tai-Shung

    2018-04-03

    Management of produced water from shale gas production is a global challenge. Vacuum membrane distillation (VMD) is considered a promising solution because of its various advantages. However, low-surface-tension species in produced water can easily deposit on the membrane surface and cause severe fouling or wetting problems. To solve the problems, an omniphobic polyvinylidene difluoride (PVDF) hollow-fiber membrane has been developed via silica nanoparticle deposition followed by a Teflon AF 2400 coating in this study. The resultant membrane shows good repellency toward various liquids with different surface tensions and chemistries, including water, ethylene glycol (EG), cooking oil, and ethanol. It also exhibits stable performance in 7 h VMD tests with a feed solution containing up to 0.6 mM of sodium dodecyl sulfate (SDS). In addition, the effects of surface energy and surface morphology as well as nanoparticle size on membrane omniphobicity have been systematically investigated. This work may provide valuable guidance to molecularly design omniphobic VMD membranes for produced water treatment.

  7. Whistler oscillitons revisited: the role of charge neutrality?

    Directory of Open Access Journals (Sweden)

    F. Verheest

    2004-01-01

    Full Text Available When studying transverse modes propagating parallel to a static magnetic field, an apparent contradiction arises between the weakly nonlinear results obtained from the derivative nonlinear Schrödinger equation, predicting envelope solitons (where the amplitude is stationary in the wave frame, but the phase is not, and recent results for whistler oscillitons, indicating that really stationary structures of large amplitude are possible. Revisiting this problem in the fluid dynamic approach, care has been taken not to introduce charge neutrality from the outset, because this not only neglects electric stresses compared to magnetic stresses, which is reasonable, but could also imply from Poisson's equation a vanishing of the wave electric field. Nevertheless, the fixed points of the remaining equations are the same, whether charge neutrality is assumed from the outset or not, so that the solitary wave solutions at not too large amplitudes will be very similar. This is borne out by numerical simulations of the solutions under the two hypotheses, showing that the lack of correspondence with the DNLS envelope solitons indicates the limitations of the reductive perturbation approach, and is not a consequence of assuming charge neutrality.

  8. Psychological Well-Being Revisited: Advances in Science and Practice

    Science.gov (United States)

    Ryff, Carol D.

    2014-01-01

    This article reviews the research and interventions that have grown up around a model of psychological well-being (Ryff, 1989) generated more than two decades ago to address neglected aspects of positive functioning, such as purposeful engagement in life, realization of personal talents and capacities, and enlightened self-knowledge. The conceptual origins of this formulation are revisited and scientific products emerging from six thematic areas are examined: (1) how well-being changes across adult development and later life, (2) what are the personality correlates of well-being, (3) how well-being is linked with experiences in family life, (4) how well-being relates to work and other community activities, (5) what are the connections between well-being and health, including biological risk factors, (6) and via clinical and intervention studies, how psychological well-being can be promoted for ever greater segments of society. Together, these topics illustrate flourishing interest across diverse scientific disciplines in understanding adults as striving, meaning-making, proactive organisms who are actively negotiating the challenges of life. A take-home message is that increasing evidence supports the health protective features of psychological well-being in reducing risk for disease and promoting length of life. A recurrent and increasingly important theme is resilience – the capacity to maintain or regain well-being in the face of adversity. Implications for future research and practice are considered. PMID:24281296

  9. Resonance effect in the allyl cation and anion: a revisit.

    Science.gov (United States)

    Mo, Yirong

    2004-08-20

    The interest over the magnitude of the conjugation effect in the allyl cation (1) and anion (2) has been revived recently by Barbour and Karty (J. Org. Chem. 2004, 69, 648-654), who derived the resonance energies of 20-22 and 17-18 kcal/mol for 1 and 2, respectively, using an empirical extrapolation approximation. This paper revisits the case by explicitly calculating the Pauling-Wheland resonance energy, which measures the stabilization from the most stable resonance structure to the delocalized energy-minimum state of a conjugated system, using our newly developed block-localized wave function (BLW) method. This BLW method has the geometrical optimization capability. The computations result in adiabatic resonance energies of 37 kcal/mol for 1 and 38 kcal/mol for 2. The significant disagreement between these values and Barbour and Karty's results originates from the neglect of structural and electronic variations in their derivation which are energy costing. Copyright 2004 American Chemical Society

  10. Revisiting the master-signifier, or, Mandela and repression

    Directory of Open Access Journals (Sweden)

    Derek eHook

    2016-01-01

    Full Text Available The concept of the master-signifier has been subject to a variety of applications in Lacanian forms of political discourse theory and ideology critique. While there is much to be commended in literature of this sort, it often neglects salient issues pertaining to the role of master signifiers in the clinical domain of (individual psychical economy. The popularity of the concept of the master (or ‘empty’ signifier in political discourse analysis has thus proved a double-edged sword. On the one hand it demonstrates how crucial psychical processes are performed via the operations of the signifier, extending thus the Lacanian thesis that identification is as much the outcome of linguistic and symbolic as opposed to merely psychological processes. On the other, the use of the master signifier concept within the political realm to track discursive formations tends to distance the term from the dynamics of the unconscious and operation of repression. Accordingly, this paper revisits the master signifier concept, and does so within the socio-political domain, yet while paying particular attention to the functioning of unconscious processes of fantasy and repression. More specifically, it investigates how Nelson Mandela operates as a master signifier in contemporary South Africa, as a vital means of knitting together diverse elements of post-apartheid society, enabling the fantasy of the post-apartheid nation, and holding at bay a whole series of repressed and negated undercurrents.

  11. Revisiting the Master-Signifier, or, Mandela and Repression.

    Science.gov (United States)

    Hook, Derek; Vanheule, Stijn

    2015-01-01

    The concept of the master-signifier has been subject to a variety of applications in Lacanian forms of political discourse theory and ideology critique. While there is much to be commended in literature of this sort, it often neglects salient issues pertaining to the role of master signifiers in the clinical domain of (individual) psychical economy. The popularity of the concept of the master (or "empty") signifier in political discourse analysis has thus proved a double-edged sword. On the one hand it demonstrates how crucial psychical processes are performed via the operations of the signifier, extending thus the Lacanian thesis that identification is the outcome of linguistic and symbolic as opposed to merely psychological processes. On the other, the use of the master signifier concept within the political realm to track discursive formations tends to distance the term from the dynamics of the unconscious and operation of repression. Accordingly, this paper revisits the master signifier concept, and does so within the socio-political domain, yet while paying particular attention to the functioning of unconscious processes of fantasy and repression. More specifically, it investigates how Nelson Mandela operates as a master signifier in contemporary South Africa, as a vital means of knitting together diverse elements of post-apartheid society, enabling the fantasy of the post-apartheid nation, and holding at bay a whole series of repressed and negated undercurrents.

  12. Revisiting heritability accounting for shared environmental effects and maternal inheritance.

    Science.gov (United States)

    Liu, Chunyu; Dupuis, Josée; Larson, Martin G; Cupples, L Adrienne; Ordovas, Jose M; Vasan, Ramachandran S; Meigs, James B; Jacques, Paul F; Levy, Daniel

    2015-02-01

    Heritability measures the proportion of phenotypic variation attributable to genetic factors. In addition to a shared nuclear genetic component, a number of additional variance components, such as spousal correlation, sibship, household and maternal effects, may have strong contributions to inter-individual phenotype variation. In humans, the confounding effects of these components on heritability have not been studied thoroughly. We sought to obtain unbiased heritability estimates for complex traits in the presence of multiple variance components and also to estimate the contributions of these variance components to complex traits. We compared regression and variance component methods to estimate heritability in simulations when additional variance components existed. We then revisited heritability for several traits in Framingham Heart Study (FHS) participants. Using simulations, we found that failure to account for or misclassification of necessary variance components yielded biased heritability estimates. The direction and magnitude of the bias varied depending on a variance structure and an estimation method. Using the best fitted models to account for necessary variance components, we found that heritability estimates for most FHS traits were overestimated, ranging from 4 to 47 %, when we compared models that considered necessary variance components to models that only considered familial relationships. Spousal correlation explained 14-36 % of phenotypic variation in several anthropometric and lifestyle traits. Maternal and sibling effects also contributed to phenotypic variation, ranging from 3 to 5 % and 4 to 7 %, respectively, in several anthropometric and metabolic traits. Our findings may explain, in part, the missing heritability for some traits.

  13. Equal-area criterion in power systems revisited.

    Science.gov (United States)

    Sun, Yong; Ma, Jinpeng; Kurths, Jürgen; Zhan, Meng

    2018-02-01

    The classic equal-area criterion (EAC) is of key importance in power system analysis, and provides a powerful, pictorial and quantitative means of analysing transient stability (i.e. the system's ability to maintain stable operation when subjected to a large disturbance). Based on the traditional EAC, it is common sense in engineering that there is a critical cleaning time (CCT); namely, a power system is stable (unstable) if a fault is cleared before (after) this CCT. We regard this form of CCT as bipartite. In this paper, we revisit the EAC theory and, surprisingly, find different kinds of transient stability behaviour. Based on these analyses, we discover that the bipartite CCT is only one type among four major types, and, actually, the forms of CCT can be diversified. In particular, under some circumstances, a system may have no CCT or show a periodic CCT. Our theoretical analysis is verified by numerical simulations in a single-machine-infinite-bus system and also in multi-machine systems. Thus, our study provides a panoramic framework for diverse transient stability behaviour in power systems and also may have a significant impact on applications of multi-stability in various other systems, such as neuroscience, climatology or photonics.

  14. Automated Guidance for Thermodynamics Essays: Critiquing Versus Revisiting

    Science.gov (United States)

    Donnelly, Dermot F.; Vitale, Jonathan M.; Linn, Marcia C.

    2015-12-01

    Middle school students struggle to explain thermodynamics concepts. In this study, to help students succeed, we use a natural language processing program to analyze their essays explaining the aspects of thermodynamics and provide guidance based on the automated score. The 346 sixth-grade students were assigned to either the critique condition where they criticized an explanation or the revisit condition where they reviewed visualizations. Within each condition, the student was assigned one of two types of tailored guidance based on the sophistication of their original essay. Both forms of guidance led to significant improvement in student understanding on the posttest. Guidance was more effective for students with low prior knowledge than for those with high prior knowledge (consistent with regression toward the mean). However, analysis of student responses to the guidance illustrates the value of aligning guidance with prior knowledge. All students were required to revise their essay as an embedded assessment. While effective, teachers involved in this study reported that revising is resisted by students and does not align with typical, vocabulary-focused classroom writing activities.

  15. Revisiting the Master-Signifier, or, Mandela and Repression

    Science.gov (United States)

    Hook, Derek; Vanheule, Stijn

    2016-01-01

    The concept of the master-signifier has been subject to a variety of applications in Lacanian forms of political discourse theory and ideology critique. While there is much to be commended in literature of this sort, it often neglects salient issues pertaining to the role of master signifiers in the clinical domain of (individual) psychical economy. The popularity of the concept of the master (or “empty”) signifier in political discourse analysis has thus proved a double-edged sword. On the one hand it demonstrates how crucial psychical processes are performed via the operations of the signifier, extending thus the Lacanian thesis that identification is the outcome of linguistic and symbolic as opposed to merely psychological processes. On the other, the use of the master signifier concept within the political realm to track discursive formations tends to distance the term from the dynamics of the unconscious and operation of repression. Accordingly, this paper revisits the master signifier concept, and does so within the socio-political domain, yet while paying particular attention to the functioning of unconscious processes of fantasy and repression. More specifically, it investigates how Nelson Mandela operates as a master signifier in contemporary South Africa, as a vital means of knitting together diverse elements of post-apartheid society, enabling the fantasy of the post-apartheid nation, and holding at bay a whole series of repressed and negated undercurrents. PMID:26834664

  16. Sex combs reduced (Scr) regulatory region of Drosophila revisited.

    Science.gov (United States)

    Calvo-Martín, Juan M; Papaceit, Montserrat; Segarra, Carmen

    2017-08-01

    The Hox gene Sex combs reduced (Scr) is responsible for the differentiation of the labial and prothoracic segments in Drosophila. Scr is expressed in several specific tissues throughout embryonic development, following a complex path that must be coordinated by an equally complex regulatory region. Although some cis-regulatory modules (CRMs) have been identified in the Scr regulatory region (~75 kb), there has been no detailed and systematic study of the distinct regulatory elements present within this region. In this study, the Scr regulatory region was revisited with the aim of filling this gap. We focused on the identification of Initiator elements (IEs) that bind segmentation factors, Polycomb response elements (PREs) that are recognized by the Polycomb and Trithorax complexes, as well as insulators and tethering elements. To this end, we summarized all currently available information, mainly obtained from high throughput ChIP data projects. In addition, a bioinformatic analysis based on the evolutionary conservation of regulatory sequences using the software MOTEVO was performed to identify IE and PRE candidates in the Scr region. The results obtained by this combined strategy are largely consistent with the CRMs previously identified in the Scr region and help to: (i) delimit them more accurately, (ii) subdivide two of them into different independent elements, (iii) identify a new CRM, (iv) identify the composition of their binding sites and (v) better define some of their characteristics. These positive results indicate that an approach that integrates functional and bioinformatic data might be useful to characterize other regulatory regions.

  17. The pulp capping procedure in primary teeth "revisited".

    Science.gov (United States)

    Kopel, H M

    1997-01-01

    The purpose of this review is to "revisit" an earlier paper (1992) on the subject of direct pulp capping in primary teeth and bring some new considerations for the procedure by the use of dentin bonding adhesives. It has come to be recognized that the customary employment of calcium hydroxide for this therapy has some shortcomings that reduce the prognosis for a favorable outcome. For at least a decade, many investigations have found that postoperative sensitivity, thermal stimuli, pulp inflammation and pathosis can be attributed not to the composition of various dental materials and their insertion techniques, but to microleakage with subsequent bacterial invasion at the enamel/restoration and the dentin/pulp interfaces. It is imperative, as pointed out, that there be an impervious resinous bond between the dentin and the dentinopulpal complex which can be achieved by the use of dentinal adhesive agents to eliminate microleakage outward movement of pulpal fluids. Various steps in the bonding technique for the treatment of deep dentin caries and/or a pulp exposure has raised some concerns for their effect on the pulp. This review discusses these concerns, which can lead to the conclusion that the use of dentinal bonding adhesives is a safe and biologically feasible procedure, whether it be in permanent or primary teeth.

  18. ISLAM, ADAT, AND THE STATE: Matrifocality in Aceh Revisited

    Directory of Open Access Journals (Sweden)

    Eka Srimulyani

    2010-08-01

    Full Text Available Matrifocality has been a rooted tradition in the social history of the community in Aceh. The principles of matrifocality have also affected on how women are positioned in the community, and the socio-gender relation within the community. The fact that Aceh has strongly associated to the Islamic values that claimed to support the paternal traditions. Apparently, the Islamic values and the local matrifocality practices juxtaposed through the roles of adat, which considered as inseparable to Islamic law or teaching, or in local term known as zat ngeun sifeut. Another point in revisiting matrifocality in Aceh in Aceh is an examination of how gender state ideology, particularly during the New Order Regime disregarded some local gender practices across some ethnics in the archipelago. Meanwhile, the state also hegemonied and promoted particular gender state ideology such as state ibuism. Nonetheless, the modernity and social changes have also contributed to the shifting of some matrifocality practices in contemporary Acehnese society. However, since the matrifocality has a strong root in the social life of the community, the principles of the matrifocality still survived until currently, although it transformed into ‘new matrifocality’ practices. Keywords: matrifocality, Aceh, gender, shari‘a law

  19. Revisiting reflexology: Concept, evidence, current practice, and practitioner training

    Directory of Open Access Journals (Sweden)

    Nurul Haswani Embong

    2015-10-01

    Full Text Available Reflexology is basically a study of how one part of the human body relates to another part of the body. Reflexology practitioners rely on the reflexes map of the feet and hands to all the internal organs and other human body parts. They believe that by applying the appropriate pressure and massage certain spots on the feet and hands, all other body parts could be energized and rejuvenated. This review aimed to revisit the concept of reflexology and examine its effectiveness, practices, and the training for reflexology practitioners. PubMed, SCOPUS, Google Scholar, and SpringerLink databases were utilized to search the following medical subject headings or keywords: foot massage, reflexology, foot reflexotherapy, reflexological treatment, and zone therapy. The articles published for the last 10 years were included. Previous systematic reviews failed to show concrete evidence for any specific effect of reflexology in any conditions. Due to its non-invasive, non-pharmacological complementary nature, reflexology is widely accepted and anecdotal evidence of positive effect reflexology in a variety of health conditions are available. Adequate training for practitioners is necessary to ensure the consistency of service provided.

  20. Single-shot work extraction in quantum thermodynamics revisited

    Science.gov (United States)

    Wang, Shang-Yung

    2018-01-01

    We revisit the problem of work extraction from a system in contact with a heat bath to a work storage system, and the reverse problem of state formation from a thermal system state in single-shot quantum thermodynamics. A physically intuitive and mathematically simple approach using only elementary majorization theory and matrix analysis is developed, and a graphical interpretation of the maximum extractable work, minimum work cost of formation, and corresponding single-shot free energies is presented. This approach provides a bridge between two previous methods based respectively on the concept of thermomajorization and a comparison of subspace dimensions. In addition, a conceptual inconsistency with regard to general work extraction involving transitions between multiple energy levels of the work storage system is clarified and resolved. It is shown that an additional contribution to the maximum extractable work in those general cases should be interpreted not as work extracted from the system, but as heat transferred from the heat bath. Indeed, the additional contribution is an artifact of a work storage system (essentially a suspended ‘weight’ that can be raised or lowered) that does not truly distinguish work from heat. The result calls into question the common concept that a work storage system in quantum thermodynamics is simply the quantum version of a suspended weight in classical thermodynamics.

  1. Pyrochlore Oxide Superconductor Cd2Re2O7 Revisited

    Science.gov (United States)

    Hiroi, Zenji; Yamaura, Jun-ichi; Kobayashi, Tatsuo C.; Matsubayashi, Yasuhito; Hirai, Daigorou

    2018-02-01

    The superconducting pyrochlore oxide Cd2Re2O7 is revisited with a particular emphasis on the sample-quality issue. The compound has drawn attention as the only superconductor (Tc = 1.0 K) that has been found in the family of α-pyrochlore oxides since its discovery in 2001. Moreover, it exhibits two characteristic structural transitions from the cubic pyrochlore structure, with the inversion symmetry broken at the first one at 200 K. Recently, it has attracted increasing attention as a candidate spin-orbit coupled metal (SOCM), in which specific Fermi liquid instability is expected to lead to an odd-parity order with spontaneous inversion-symmetry breaking [http://doi.org/10.1103/PhysRevLett.115.026401" xlink:type="simple">L. Fu, Phys. Rev. Lett. 115, 026401 (2015)] and parity-mixing superconductivity [http://doi.org/10.1103/PhysRevLett.115.207002" xlink:type="simple">V. Kozii and L. Fu, Phys. Rev. Lett. 115, 207002 (2015); http://doi.org/10.1103/PhysRevB.93.134512" xlink:type="simple">Y. Wang et al., Phys. Rev. B 93, 134512 (2016)]. We review our previous experimental results in comparison with those of other groups in the light of the theoretical prediction of the SOCM, which we consider meaningful and helpful for future progress in understanding this unique compound.

  2. The evolution of the mitochondrial genetic code in arthropods revisited.

    Science.gov (United States)

    Abascal, Federico; Posada, David; Zardoya, Rafael

    2012-04-01

    A variant of the invertebrate mitochondrial genetic code was previously identified in arthropods (Abascal et al. 2006a, PLoS Biol 4:e127) in which, instead of translating the AGG codon as serine, as in other invertebrates, some arthropods translate AGG as lysine. Here, we revisit the evolution of the genetic code in arthropods taking into account that (1) the number of arthropod mitochondrial genomes sequenced has triplicated since the original findings were published; (2) the phylogeny of arthropods has been recently resolved with confidence for many groups; and (3) sophisticated probabilistic methods can be applied to analyze the evolution of the genetic code in arthropod mitochondria. According to our analyses, evolutionary shifts in the genetic code have been more common than previously inferred, with many taxonomic groups displaying two alternative codes. Ancestral character-state reconstruction using probabilistic methods confirmed that the arthropod ancestor most likely translated AGG as lysine. Point mutations at tRNA-Lys and tRNA-Ser correlated with the meaning of the AGG codon. In addition, we identified three variables (GC content, number of AGG codons, and taxonomic information) that best explain the use of each of the two alternative genetic codes.

  3. Revisiting Cross-Channel Information Transfer for Chromatic Aberration Correction

    KAUST Repository

    Sun, Tiancheng

    2017-12-25

    Image aberrations can cause severe degradation in image quality for consumer-level cameras, especially under the current tendency to reduce the complexity of lens designs in order to shrink the overall size of modules. In simplified optical designs, chromatic aberration can be one of the most significant causes for degraded image quality, and it can be quite difficult to remove in post-processing, since it results in strong blurs in at least some of the color channels. In this work, we revisit the pixel-wise similarity between different color channels of the image and accordingly propose a novel algorithm for correcting chromatic aberration based on this cross-channel correlation. In contrast to recent weak prior-based models, ours uses strong pixel-wise fitting and transfer, which lead to significant quality improvements for large chromatic aberrations. Experimental results on both synthetic and real world images captured by different optical systems demonstrate that the chromatic aberration can be significantly reduced using our approach.

  4. An Adaptive and Hybrid Approach for Revisiting the Visibility Pipeline

    Directory of Open Access Journals (Sweden)

    Ícaro Lins Leitão da Cunha

    2016-04-01

    Full Text Available We revisit the visibility problem, which is traditionally known in Computer Graphics and Vision fields as the process of computing a (potentially visible set of primitives in the computational model of a scene. We propose a hybrid solution that uses a dry structure (in the sense of data reduction, a triangulation of the type J1a, to accelerate the task of searching for visible primitives. We came up with a solution that is useful for real-time, on-line, interactive applications as 3D visualization. In such applications the main goal is to load the minimum amount of primitives from the scene during the rendering stage, as possible. For this purpose, our algorithm executes the culling by using a hybrid paradigm based on viewing-frustum, back-face culling and occlusion models. Results have shown substantial improvement over these traditional approaches if applied separately. This novel approach can be used in devices with no dedicated processors or with low processing power, as cell phones or embedded displays, or to visualize data through the Internet, as in virtual museums applications.

  5. The hateful patient revisited: Relevance for 21st century medicine.

    Science.gov (United States)

    Strous, Rael D; Ulman, Anne-Marie; Kotler, Moshe

    2006-10-01

    While the practice of medicine has changed over the years, including technological advances, access to medical information, and the narrowing of socio-economic and educational gaps between the clinician and his/her patients, the importance of the doctor-patient relationship has not diminished over time. This can be a very rewarding interaction. However, many physicians experience a great deal of anger, inadequacy and frustration, and much of the actual practice of medicine may become a burden rather than a source of satisfaction. Physicians may encounter a subset of patients who engender strong negative feelings, despair and even downright malice. An understanding of the "hateful patient" can therefore be very informative to the physician. Several categories of such patients may be described, and sensitivity to the phenomenon will lead to improved physician well-being, less self-destructive patient behavior and a lower risk of litigation. Several factors may assist the 21st century physician in managing the "hateful patient" in an empathic manner and in making some sense of why the patient has resorted to negative response patterns. Ultimately, a failure to consider these issues will result in poorer medical care and, no less important, reduced satisfaction of both patients and doctors. The intention of this article is to revisit the concept and to place it in the context of contemporary medical practice.

  6. Oxygen Transport Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

    2004-05-01

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, in situ neutron diffraction was used to characterize the chemical and structural properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} (here after as L2SF55T) specimen, which was subject to measurements of neutron diffraction from room temperature to 900 C in N{sub 2}. Space group of R3c was found to result in a better refinement and is used in this study. The difference for crystal structure, lattice parameters and local crystal chemistry for LSFT nearly unchanged when gas environment switched from air to N{sub 2}. Stable crack growth studies on Dense OTM bars provided by Praxair were done at room temperature in air. A bridge-compression fixture was fabricated to achieve stable pre-cracks from Vickers indents. Post fracture evaluation indicated stable crack growth from the indent and a regime of fast fracture. Post-fracture X-ray data of the OTM fractured at 1000 C in environment were refined by FullProf code and results indicate a distortion of the parent cubic perovskite to orthorhombic structure with reduced symmetry. TGA-DTA studies on the post-fracture samples also indicated residual effect arising from the thermal and stress history of the samples. The thermal and chemical expansion of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} were studied at 800 {le} T {le} 1000 C and at {approx} 1 x 10{sup -15} {le} pO{sub 2} {le} 0.21 atm. The thermal expansion coefficient of the sample was calculated from the dilatometric analysis in the temperature range between room temperature and 1200 C in air. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of

  7. Characterization of polyacrylonitrile ultrafiltration membranes

    NARCIS (Netherlands)

    Germic, J.; Germic, J.; Ebert, K.; Ebert, K.; Bouma, R.H.B.; Bouma, R.H.B.; Borneman, Zandrie; Mulder, M.H.V.; Strathmann, H.

    1997-01-01

    Various methods have been used to characterize ultrafiltration membranes, such as gas flux measurements, (field emission) scanning electron microscopy, permporometry and liquid-liquid displacement. Significant differences in the pore size distributions determined from permporometry and liquid-liquid

  8. Membrane Trafficking and Vesicle Fusion

    Indian Academy of Sciences (India)

    IAS Admin

    hemophagocytic syndrome) and metabolic (diabe- tes) disorders [2, 23, 33]. Mutations in the genes of the basic secretory protein machinery lead to a number of membrane trafficking diseases such as Charcot–Marie–Tooth disease, Cohen.

  9. Layered plasma polymer composite membranes

    Science.gov (United States)

    Babcock, Walter C.

    1994-01-01

    Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is .gtoreq.2 and is the number of selective layers.

  10. Membranes in Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Junbo Hou

    2012-07-01

    Full Text Available Lithium ion batteries have proven themselves the main choice of power sources for portable electronics. Besides consumer electronics, lithium ion batteries are also growing in popularity for military, electric vehicle, and aerospace applications. The present review attempts to summarize the knowledge about some selected membranes in lithium ion batteries. Based on the type of electrolyte used, literature concerning ceramic-glass and polymer solid ion conductors, microporous filter type separators and polymer gel based membranes is reviewed.

  11. Static and Dynamic Membrane Structures

    Directory of Open Access Journals (Sweden)

    Sergiu Ivanov

    2012-10-01

    Full Text Available While originally P systems were defined to contain multiset rewriting rules, it turned out that considering different types of rules may produce important results, such as increasing the computational power of the rules. This paper focuses on factoring out the concept of a membrane structure out of various P system models with the goal of providing useful formalisations. Both static and dynamic membrane structures are considered.

  12. Gas separation membrane module assembly

    Science.gov (United States)

    Wynn, Nicholas P [Palo Alto, CA; Fulton, Donald A [Fairfield, CA

    2009-03-31

    A gas-separation membrane module assembly and a gas-separation process using the assembly. The assembly includes a set of tubes, each containing gas-separation membranes, arranged within a housing. The housing contains a tube sheet that divides the space within the housing into two gas-tight spaces. A permeate collection system within the housing gathers permeate gas from the tubes for discharge from the housing.

  13. Hybrid membranes for fuel cells

    Science.gov (United States)

    Bochkareva, S. S.; Shashkina, S. S.

    2018-01-01

    Fuel cells are a very efficient, reliable, durable, and environmentally friendly energy source. Membranes for fuel cells were developed based on nitrogen-containing high-molecular compounds and organic–inorganic composites. Their electrical conductivities were measured. The influence of a silicon block of composites on the proton exchange properties of membranes was proved.The comparative characterization of the studied materials was performed.

  14. The metric theory of tensor products (grthendieck's résumé revisited ...

    African Journals Online (AJOL)

    The metric theory of tensor products (grthendieck's résumé revisited) part 2: Bilinear forms and linear operators of type α. ... Mathematics Subject Classification (2000): 46B28, 46B07, 46B10. Key words: α-forms;α-integral operators; (metric) accessibility; α-nuclear forms (operators). Quaestiones Mathematicae 25 (2002), 73- ...

  15. Commentary on "Distributed Revisiting: An Analytic for Retention of Coherent Science Learning"

    Science.gov (United States)

    Hewitt, Jim

    2015-01-01

    The article, "Distributed Revisiting: An Analytic for Retention of Coherent Science Learning" is an interesting study that operates at the intersection of learning theory and learning analytics. The authors observe that the relationship between learning theory and research in the learning analytics field is constrained by several…

  16. Rigor Revisited: Scaffolding College Student Learning by Incorporating Their Lived Experiences

    Science.gov (United States)

    Castillo-Montoya, Milagros

    2018-01-01

    This chapter explores how students' lived experiences contribute to the rigor of their thinking. Insights from research indicate faculty can enhance rigor by accounting for the many ways it may surface in the classroom. However, to see this type of rigor, we must revisit the way we conceptualize it for higher education.

  17. “Abba” revisited: merging the horizons of history and rhetoric ...

    African Journals Online (AJOL)

    Abba” revisited: merging the horizons of history and rhetoric through the new rhetoric structure for metaphors. ... illustrated that, by using the approach of the New Rhetoric in describing a metaphor, an interpreter can raise questions on both the understanding of the author and readers, as part of the communication process.

  18. Revisiting Individual Creativity Assessment: Triangulation in Subjective and Objective Assessment Methods

    Science.gov (United States)

    Park, Namgyoo K.; Chun, Monica Youngshin; Lee, Jinju

    2016-01-01

    Compared to the significant development of creativity studies, individual creativity research has not reached a meaningful consensus regarding the most valid and reliable method for assessing individual creativity. This study revisited 2 of the most popular methods for assessing individual creativity: subjective and objective methods. This study…

  19. The Best and the Rest: Revisiting the Norm of Normality of Individual Performance

    Science.gov (United States)

    O'Boyle, Ernest, Jr.; Aguinis, Herman

    2012-01-01

    We revisit a long-held assumption in human resource management, organizational behavior, and industrial and organizational psychology that individual performance follows a Gaussian (normal) distribution. We conducted 5 studies involving 198 samples including 633,263 researchers, entertainers, politicians, and amateur and professional athletes.…

  20. The skeptical green consumer revisited: testing the relationship between green consumerism and skepticism toward advertising

    NARCIS (Netherlands)

    Matthes, J.; Wonneberger, A.

    2014-01-01

    This article revisits the widely believed notion of the skeptical green consumer, in other words, that green consumers tend to distrust green advertising. Study 1, a survey of U.S. consumers, found no positive relationship between green consumerism and general ad skepticism. However, green

  1. My First CMC Article Revisited: A Window on Spanish L2 Interlanguage

    Science.gov (United States)

    Blake, Robert

    2016-01-01

    The computer-assisted language learning (CALL) field seems to change overnight with new technological affordances. Blake revisits his 2000 "LLT" article on computer-mediation communication (CMC) in order to reflect on how the field has examined this topic over the past decade or so. While the Interaction Hypothesis continues to guide…

  2. Trade Unions, immigration and immigrants in Europe revisited: Unions’ attitudes and actions under new conditions

    NARCIS (Netherlands)

    Marino, S.; Penninx, R.; Roosblad, J.

    2015-01-01

    This paper revisits the comparative approach used by Penninx and Roosblad (Trade Unions, Immigration and Immigrants in Europe, 1960-1993. New York: Berghahn Books) to study trade unions’ attitudes and actions in relation to immigrant workers in seven Western European countries. It reassesses that

  3. Revisiting the Gun Ownership and Violence Link; a multi- level analysis of victimisation survey data.

    NARCIS (Netherlands)

    van Kesteren, J.N.

    2014-01-01

    The link between gun ownership victimisation by violent crime remains one of the most contested issues in criminology. Some authors claim that high gun availability facilitates serious violence. Others claim that gun ownership prevents crime. This article revisits these issues using individual and

  4. Revisiting the Didactic Triangle in the Case of an Adaptive Learning System

    Directory of Open Access Journals (Sweden)

    Yassine Zaoui Seghroucheni

    2014-10-01

    Full Text Available In this paper we revisit the classical approach of the didactic triangle designed for the classical learning situation (face to face and adapt it to the situation of an adaptive learning system, we discuss also the different components involved in this didactic triangle and how they interact and influence the learning process in an adaptive learning system.

  5. What are museums for? - Revisiting “Museums in a Troubled World”

    DEFF Research Database (Denmark)

    Søndergaard, Morten Karnøe; Janes, Robert

    2012-01-01

    Focusing on the present situation in the Nordic museum scene, entailing economic pressures and restructuring, this article introduces the thoughts and ideas of Canadian museum expert and author, Robert R. Janes, to put things in perspective. After revisiting the 2009 book “Museums in a Troubled W...

  6. Globalisation, the Singapore Developmental State and Education Policy: A Thesis Revisited

    Science.gov (United States)

    Gopinathan, S.

    2007-01-01

    In this article I revisit and extend arguments made in 1996 and 1997 about the relationship between globalisation, the state and education policy. I was particularly concerned then to see how a small but strong state, Singapore, was responding in the education arena to globalisation. I also wished to draw attention to the literature on the high…

  7. A Gender Lens on Pedagogical Choice in Academia: Revisiting Hartlaub and Lancaster's Study on Teaching Methodologies

    Science.gov (United States)

    Wigfall, Patricia Moss; Hall, Paula Quick

    2010-01-01

    This paper focuses on the role of gender in faculty choice of teaching methodologies at colleges and universities in North Carolina. We replicate research conducted by Hartlaub and Lancaster who examined pedagogical preference among a national sample of political science instructors. In revisiting that inquiry, published in 2008, we have explored…

  8. Even-tempered Slater-type orbitals revisited: from hydrogen to krypton

    NARCIS (Netherlands)

    Chong, D.P.; van Lenthe, E.; Dr. van Gisbergen, S.; Baerends, E.J.

    2004-01-01

    Even-tempered Slater-type orbital basis sets were developed in 1973, based on total atomic energy optimization. Here, we revisit ET STOs and propose new sets based on past experience and recent computational studies. From preliminary atomic and molecular tests, these sets are shown to be very well

  9. Teacher Communication Concerns Revisited: Calling into Question the Gnawing Pull towards Equilibrium

    Science.gov (United States)

    Dannels, Deanna P.

    2015-01-01

    This study revisits the long-standing teacher communication concerns framework originating over three decades ago. Analysis of 10 years of contemporary GTA teacher communication concerns reveals a typology of 10 concerns, which taken together construct teaching as a process of negotiating relationships, managing identities, and focusing attention.…

  10. The Peter Effect Revisited: Reading Habits and Attitudes of College Students

    Science.gov (United States)

    Applegate, Anthony J.; Applegate, Mary DeKonty; Mercantini, Martha A.; McGeehan, Catherine M.; Cobb, Jeanne B.; DeBoy, Joanne R.; Modla, Virginia B.; Lewinski, Kimberly E.

    2014-01-01

    Certainly a primary goal of literacy education is the creation of avid, enthusiastic, and highly motivated readers. However, in this article revisiting the Peter Effect (Applegate & Applegate, 2004), researchers surveyed more than 1,000 college sophomores and found strikingly low levels of enthusiasm for reading. Only 46.6% of surveyed…

  11. Double digest revisited : Complexity and Approximability in the Presence of Noisy Data

    NARCIS (Netherlands)

    Cieliebak, Mark; Eidenbenz, Stephan; Woeginger, Gerhard; Warnow, Tandy; Zhu, Binhai

    2003-01-01

    We revisit the Double Digest problem, which occurs in sequencing of large DNA strings and consists of reconstructing the relative positions of cut sites from two different enzymes: we first show that Double Digest is strongly NP-complete, improving upon previous results that only showed weak

  12. Revisiting the use of sPLA2-sensitive liposomes in cancer therapy

    DEFF Research Database (Denmark)

    Pourhassan, Houman; Clergeaud Veiga, Gael; Hansen, Anders Elias

    2017-01-01

    The first developed secretory phospholipase A2 (sPLA2) sensitive liposomal cisplatin formulation (LiPlaCis®) is currently undergoing clinical evaluation. In the present study we revisit and evaluate critical preclinical parameters important for the therapeutic potential and safety of platinum dru...

  13. Service-Learning in Crisis Communication Education: Revisiting Coombs' Objectives for the Crisis Communication Course

    Science.gov (United States)

    Maresh-Fuehrer, Michelle M.

    2015-01-01

    The purpose of this study was to revisit Coombs' suggestions for teaching the crisis communication course using service-learning as a framework. The author sought to assess the effectiveness of using this method in terms of the benefits to both students and the partnering organization and students' perceptions of whether they met the learning…

  14. Revisiting First-Year College Students' Mattering: Social Support, Academic Stress, and the Mattering Experience

    Science.gov (United States)

    Rayle, Andrea Dixon; Chung, Kuo-Yi

    2008-01-01

    In this study, Nancy Schlossberg's (1989) theory of college students' mattering to others was revisited. Mattering is the experience of others depending on us, being interested in us, and being concerned with our fate. The relationships of gender, mattering to college friends and the college environment, and friend and family social support with…

  15. The Tension between the Decision and Control Perspectives of Accounting Revisited

    DEFF Research Database (Denmark)

    Christensen, John

    2009-01-01

    to use different accounting systems for different purposes. That is not the norm. The tensions are managed within a single accounting system and that leads to trade-offs in the accounting system. I will revisit these conflicts of uses of accounting systems using product costing, transfer pricing and fair...... value as examples....

  16. Hypothermic machine preservation in liver transplantation revisited : Concepts and criteria in the new millennium

    NARCIS (Netherlands)

    van der Plaats, A; t'Hart, NA; Verkerke, GJ; Leuvenink, HGD; Ploeg, RJ; Rakhorst, G

    To overcome the present shortage of liver donors by expansion of the existing donor pool and possibly lengthening of the storage time, hypothermic machine perfusion of the liver as a dynamic preservation method is revisited. The three most important aspects are defined to be the type of preservation

  17. Revisiting the Metaphor of the Island: Challenging "World Culture" from an Island Misunderstood

    Science.gov (United States)

    Rappleye, Jeremy

    2015-01-01

    This article revisits the newly "discovered" island that world culture theorists have repeatedly utilised to explain their theoretical stance, conceptual preferences and methodological approach. Yet, it seeks to (re)connect world culture with the real world by replacing their imagined atoll with a real one--the island-nation of Japan. In…

  18. Revisiting Learning in Higher Education--Framing Notions Redefined through an Ecological Perspective

    Science.gov (United States)

    Damsa, Crina; Jornet, Alfredo

    2016-01-01

    This article employs an ecological perspective as a means of revisiting the notion of learning, with a particular focus on learning in higher education. Learning is reconceptualised as a process entailing mutually constitutive, epistemic, social and affective relations in which knowledge, identity and agency become collective achievements of whole…

  19. Re-Visit to the School Nurse and Adolescents' Medicine Use

    Science.gov (United States)

    Borup, Ina K.; Andersen, Anette; Holstein, Bjorn E.

    2011-01-01

    Objective: To examine if students who re-visit the school nurse use medicines differently than other students when exposed to aches and psychological problems. Methods: The study includes all 11-, 13- and 15-year-old students from a random sample of schools in Denmark, response rate 87 per cent, n = 5,205. The data collection followed the…

  20. Creative Experience and Revisit Intention of Handmade Oriental Parasol Umbrella in Kaohsiung

    OpenAIRE

    Yi-Ju Lee

    2015-01-01

    This study identified the hypothesised relationship between creative experience, and revisit intention of handmade oriental parasol umbrella in Kaohsiung, Taiwan. A face-to-face questionnaire survey was administered in Meinong town, Kaohsiung. The components of creative experience were found as "sense of achievement", "unique learning" and "interaction with instructors" in creative tourism. The result also revealed significant positive relationships between creative exper...

  1. Using destination image to predict visitors' intention to revisit three Hudson River Valley, New York, communities

    Science.gov (United States)

    Rudy M. Schuster; Laura Sullivan; Duarte Morais; Diane Kuehn

    2009-01-01

    This analysis explores the differences in Affective and Cognitive Destination Image among three Hudson River Valley (New York) tourism communities. Multiple regressions were used with six dimensions of visitors' images to predict future intention to revisit. Two of the three regression models were significant. The only significantly contributing independent...

  2. Membrane structure in disease and drug therapy

    National Research Council Canada - National Science Library

    Zimmer, G

    2000-01-01

    ...) interaction with membranous transport systems (opening or closing of ion or substrate channels); (2) reaction with receptors; (3) activation or inhibition of membrane enzymes; or (4) cytosolic membranous signaling and exchange. These consequences within the membrane influence intracellular wellbeing: life is possible only if a bala...

  3. Ninth International Workshop on Plant Membrane Biology

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

    This report is a compilation of abstracts from papers which were discussed at a workshop on plant membrane biology. Topics include: plasma membrane ATP-ases; plant-environment interactions, membrane receptors; signal transduction; ion channel physiology; biophysics and molecular biology; vaculor H+ pumps; sugar carriers; membrane transport; and cellular structure and function.

  4. Nanomaterial-enabled membranes for water treatment

    Science.gov (United States)

    Rogensues, Adam Roy

    Incorporating engineered nanomaterials as components of synthetic membranes can improve their separation performance and endow membranes with additional functions. This work explores two approaches to the design of membranes modified with nanomaterials. In the first chapter, exfoliated graphite nanoplatelets (xGnP) decorated with gold nanoparticles were embedded in a polysulfone matrix to fabricate phase inversion nanocomposite membranes. The cast membranes were evaluated as flow-through membrane reactors in experiments on the catalytic reduction of 4-nitrophenol. The nanocomposite membranes were not as catalytically efficient as those fabricated by modifying anodized alumina membranes polyelectrolyte multilayers (PEMs) containing gold nanoparticles. However, because of the facility of membrane casting by phase inversion and new opportunities enabled by the demonstrated hierarchy-based approach to nanocomposite membrane design, such membrane may hold commercial promise. In the second part of the study, the practicability of PEM-based nanofiltration was evaluated under conditions of precipitative fouling (i.e. scaling) by calcium sulfate. Polyelectrolytes were deposited onto 50 kDa polyethersulfone membranes to create PEM-based nanofiltration membranes. The prepared membranes were compared with the commercial NF270 membrane in terms of flux and rejection performance, as well as the morphology of gypsum crystals formed on the membrane surface. None of the PEM coatings tested inhibited scale formation.

  5. Hydrogen purifier module with membrane support

    Science.gov (United States)

    A hydrogen purifier utilizing a hydrogen-permeable membrane to purify hydrogen from mixed gases containing hydrogen is disclosed. Improved mechanical support for the permeable membrane is described, enabling forward or reverse differential pressurization of the membrane, which further stabilizes the membrane from wrinkling upon hydrogen uptake.

    2012-07-24

    A hydrogen purifier utilizing a hydrogen-permeable membrane to purify hydrogen from mixed gases containing hydrogen is disclosed. Improved mechanical support for the permeable membrane is described, enabling forward or reverse differential pressurization of the membrane, which further stabilizes the membrane from wrinkling upon hydrogen uptake.

  6. Inflation and Failure of Polymeric Membranes

    DEFF Research Database (Denmark)

    Hassager, Ole; Neergaard, Jesper

    2000-01-01

    We consider the inflation of an axisymmetric polymeric membrane.Some membranes composed of viscoelastic materialsdescribed by a Mooney-Rivlin model show a monotone increasingpressure during inflation. These materialsdevelop a homogeneous membrane thickness in agreement with the Considere...... is found to stabilize the inflated polymer membrane....

  7. Membrane properties for permeability testing: Skin versus synthetic membranes.

    Science.gov (United States)

    Haq, Anika; Dorrani, Mania; Goodyear, Benjamin; Joshi, Vivek; Michniak-Kohn, Bozena

    2018-03-25

    Synthetic membranes that are utilized in diffusion studies for topical and transdermal formulations are usually porous thin polymeric sheets for example cellulose acetate (CA) and polysulfones. In this study, the permeability of human skin was compared using two synthetic membranes: cellulose acetate and Strat-M® membrane and lipophilic and hydrophilic compounds either as saturated or formulated solutions as well as marketed dosage forms. Our data suggests that hydrophilic compounds have higher permeation in Strat-M membranes compared with lipophilic ones. High variation in permeability values, a typical property of biological membranes, was not observed with Strat-M. In addition, the permeability of Strat-M was closer to that of human skin than that of cellulose acetate (CA > Strat-M > Human skin). Our results suggest that Strat-M with little or no lot to lot variability can be applied in pilot studies of diffusion tests instead of human skin and is a better substitute than a cellulose acetate. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Superhydrophobic Membrane Contactor for Acid Gas Removal

    Science.gov (United States)

    Faiqotul Himma, Nurul; Gede Wenten, I.

    2017-07-01

    Gas-liquid membrane contactor has gained a great attention as an alternative to conventional absorption columns in acid gas removal from natural gas or post-combustion. The membrane contactor offers high mass transfer area and excellent operational flexibility. However, hydrophobic microporous membranes commonly used are still susceptible to wetting by liquid absorbents, leading to the deterioration of absorption performance in long-term operation. Therefore, many studies were recently directed to improve the membrane wetting resistant by endowing superhydrophobicity. This article then presents a review on superhydrophobic membrane development and its application for acid gas removal using membrane contactor. An overview of gas-liquid membrane contactor is firstly presented, followed by the preparation of superhydrophobic membranes. The performances of superhydrophobic membranes in acid gas absorption are then discussed, and the recommendation for future research is finally outlined. This review may provide an insight into the further development of superhydrophobic membrane contactor.

  9. Examining Relationships of Destination Image, Service Quality, e-WOM, and Revisit Intention to Sabang Island, Indonesia

    Directory of Open Access Journals (Sweden)

    Rangga Restu Prayogo

    2016-12-01

    Full Text Available The purpose of this research is to study the relationship among destination image, service quality, e-WOM, and revisit intentions in the tourism industry. A questionnaire given to tourists who visit one of the farrest island in western part of Indonesia, Sabang Island and using sampling through the convenience sampling. A structural equation model (SEM test with WarpPLS 3.0 was used to test the relationship between research variables. This research gathered from 150 respondents. The empirical results from PLS-SEM showed that; the destination image positive affect e-WOM and revisit intention; service quality affect e-WOM and revisit intention; e-WOM positive affect to revisit intention tourists. The implications and future research issues were discussed.

  10. PERANAN SERVICE QUALITY TERHADAP PATIENT REVISIT INTENTION MELALUI PATIENT SATISFACTION PADA RUMAH SAKIT UMUM DAN RUMAH SAKIT SWASTA TIPE B

    Directory of Open Access Journals (Sweden)

    Febry Adhiana

    2008-03-01

    Findin s: There are no differences between private and public hospitals in service quality, patient satisf Um and patient revisit intention. Finally the implications of the results are highlighted for health :are managers.

  11. Modeling electrically active viscoelastic membranes.

    Directory of Open Access Journals (Sweden)

    Sitikantha Roy

    Full Text Available The membrane protein prestin is native to the cochlear outer hair cell that is crucial to the ear's amplification and frequency selectivity throughout the whole acoustic frequency range. The outer hair cell exhibits interrelated dimensional changes, force generation, and electric charge transfer. Cells transfected with prestin acquire unique active properties similar to those in the native cell that have also been useful in understanding the process. Here we propose a model describing the major electromechanical features of such active membranes. The model derived from thermodynamic principles is in the form of integral relationships between the history of voltage and membrane resultants as independent variables and the charge density and strains as dependent variables. The proposed model is applied to the analysis of an active force produced by the outer hair cell in response to a harmonic electric field. Our analysis reveals the mechanism of the outer hair cell active (isometric force having an almost constant amplitude and phase up to 80 kHz. We found that the frequency-invariance of the force is a result of interplay between the electrical filtering associated with prestin and power law viscoelasticity of the surrounding membrane. Paradoxically, the membrane viscoelasticity boosts the force balancing the electrical filtering effect. We also consider various modes of electromechanical coupling in membrane with prestin associated with mechanical perturbations in the cell. We consider pressure or strains applied step-wise or at a constant rate and compute the time course of the resulting electric charge. The results obtained here are important for the analysis of electromechanical properties of membranes, cells, and biological materials as well as for a better understanding of the mechanism of hearing and the role of the protein prestin in this mechanism.

  12. Real-time examination of aminoglycoside activity towards bacterial mimetic membranes using Quartz Crystal Microbalance with Dissipation monitoring (QCM-D).

    Science.gov (United States)

    Joshi, Tanmaya; Voo, Zhi Xiang; Graham, Bim; Spiccia, Leone; Martin, Lisandra L

    2015-02-01

    The rapid increase in multi-drug resistant bacteria has resulted in previously discontinued treatments being revisited. Aminoglycosides are effective "old" antibacterial agents that fall within this category. Despite extensive usage and understanding of their intracellular targets, there is limited mechanistic knowledge regarding how aminoglycosides penetrate bacterial membranes. Thus, the activity of two well-known aminoglycosides, kanamycin A and neomycin B, towards a bacterial mimetic membrane (DMPC:DMPG (4:1)) was examined using a Quartz Crystal Microbalance with Dissipation monitoring (QCM-D). The macroscopic effect of increasing the aminoglycoside concentration showed that kanamycin A exerts a threshold response, switching from binding to the membrane to disruption of the surface. Neomycin B, however, disrupted the membrane at all concentrations examined. At concentrations above the threshold value observed for kanamycin A, both aminoglycosides revealed similar mechanistic details. That is, they both inserted into the bacterial mimetic lipid bilayer, prior to disruption via loss of materials, presumably aminoglycoside-membrane composites. Depth profile analysis of this membrane interaction was achieved using the overtones of the quartz crystal sensor. The measured data is consistent with a two-stage process in which insertion of the aminoglycoside precedes the 'detergent-like' removal of membranes from the sensor. The results of this study contribute to the insight required for aminoglycosides to be reconsidered as active antimicrobial agents/co-agents by providing details of activity at the bacterial membrane. Kanamycin and neomycin still offer potential as antimicrobial therapeutics for the future and the QCM-D method illustrates great promise for screening new antibacterial or antiviral drug candidates. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Revisiting Nuclear Thermal Propulsion for Human Mars Exploration

    Science.gov (United States)

    Percy, Thomas K.; Rodriguez, Mitchell

    2017-01-01

    Nuclear Thermal Propulsion (NTP) has long been considered as a viable in-space transportation alternative for delivering crew and cargo to the Martian system. While technology development work in nuclear propulsion has continued over the year, general interest in NTP propulsion applications has historically been tied directly to the ebb and flow of interest in sending humans to explore Mars. As far back as the 1960’s, plans for NTP-based human Mars exploration have been proposed and periodically revisited having most recently been considered as part of NASA Design Reference Architecture (DRA) 5.0. NASA has been investigating human Mars exploration strategies tied to its current Journey to Mars for the past few years however, NTP has only recently been added into the set of alternatives under consideration for in-space propulsion under the Mars Study Capability (MSC) team, formerly the Evolvable Mars Campaign (EMC) team. The original charter of the EMC was to find viable human Mars exploration approaches that relied heavily on technology investment work already underway, specifically related to the development of large Solar Electric Propulsion (SEP) systems. The EMC team baselined several departures from traditional Mars exploration ground rules to enable these types of architectures. These ground rule changes included lower energy conjunction class trajectories with corresponding longer flight times, aggregation of mission elements in cis-Lunar space rather than Low Earth Orbit (LEO) and, in some cases, the pre-deployment of Earth return propulsion systems to Mars. As the MSC team continues to refine the in-space transportation trades, an NTP-based architecture that takes advantage of some of these ground rule departures is being introduced.

  14. Memory Revisited in Julian Barnes's The Sense of an Ending

    Directory of Open Access Journals (Sweden)

    Maricel Oró Piqueras

    2014-02-01

    Full Text Available An accumulation of years brings with it an accumulation of experiences. The revision of such experiences usually becomes more recurrent after retirement, a transition time from one period of life to another and, as such, a time in which we, human beings, have a tendency to take stock of our lives. This is actually one of the main issues present in Julian Barnes's last novel The Sense of an Ending (2011. When the main protagonist, a retired man quite comfortable and contented with his present life, receives an unexpected inheritance from the mother of a girlfriend from his university years, he is forced to track down a part of his life that he had left at the back of his mind a long time ago. As he explains his story, the protagonist and narrator of the novel raises a number of questions related to the quality and function of memory as one gets into old age. He experiments the unreliability of memory and questions to what extent memory is constructed through the remembered emotions that invaded him over that episode of his life rather than through the events as they actually took place. On the other hand, the act of revisiting and revising that specific episode, brings with it feelings of guilt and remorse as the protagonist realises that his past acts were not as noble as he remembered them to be. However, these acts are part of the past and they cannot be changed; thus, another question that the novel raises is how to account for those actions of which one does not feel proud and, more importantly, how to manage those bad memories as one gets older

  15. "Research on Infertility: Definition Makes a Difference" Revisited.

    Science.gov (United States)

    Jacobson, Melanie H; Chin, Helen B; Mertens, Ann C; Spencer, Jessica B; Fothergill, Amy; Howards, Penelope P

    2018-02-01

    In a 1989 paper, Marchbanks et al. (Am J Epidemiol. 1989;130(2):259-267) noted inconsistent definitions of infertility across research and clinical practice and examined differences in prevalence estimates across definitions. Since their study, there have been substantial changes in society, technology, and clinical practice related to female reproductive health. In response, we revisited the original paper using data from a recent study among reproductive-aged women. Internal comparisons across various definitions of infertility were made by assessing how many and which women were classified as infertile, their age at infertility, and the probability of spontaneous pregnancy after infertility. Results were also compared with Marchbanks et al. Black women were more likely to be classified as infertile than white women based on the definition "12 months of unprotected intercourse" (40.1% vs. 33.7%) but less likely by "12 months of attempting pregnancy" (14.3% vs. 21.8%) and "visiting a doctor for help getting pregnant" (8.4% vs. 19.7%). After unprotected intercourse for 12 months, 36.1% of women who were attempting pregnancy spontaneously conceived by 6 months compared with 13.5% of women who were not attempting pregnancy. While our results for most infertility definitions were similar to those of Marchbanks et al., prevalence estimates continued to differ across demographic groups by definition. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. What are 'Think Tanks'? Revisiting the Dilemma of the Definition

    Directory of Open Access Journals (Sweden)

    Juliana Cristina Rosa Hauck

    2017-08-01

    Full Text Available 'Think tanks' (TTs are 'sui generis' organizations that have been proliferating, playing more and more the role of very relevant actors on the political scene in clashes over interests, preferences and ideas for the formation of public policies. The definition of 'think tank', however, creates a conceptual gap that causes serious limitations on the development of this field of study. Excessive generality or inflexibility in the use of the concept raises questions about the validity of the category. Either way, the 'trade offs' of the conceptual choices have delineated a not very useful concept of think tank to both inter-contextual and inter-organizational comparability and to differentiate think thanks from overlapping organizations. The article revisits some of these dilemmas. To do so, the treatment in the specialized literature of the analytic category, highlighting both the insensitivity of the traditional North American matrix to different national contexts and its obsolescence to the changes in the context of TTs' action, including their own context of origin, is explained. In shedding light on promising conceptual contributions, the main contribution of the present article is the proposal of the radial structuring of the concept of think tanks as 'boundary spanners', as advanced by Medvetz, and of corresponding indicators to deal with the large variation in the substantive properties of the operationalization of the adopted concept. Thus, the aim is to reduce non-specificities in the analytic category and the dissent of its social significance, which demands less abstraction facing the exploratory state of the field of study.

  17. Sub-Chandrasekhar-mass White Dwarf Detonations Revisited

    Science.gov (United States)

    Shen, Ken J.; Kasen, Daniel; Miles, Broxton J.; Townsley, Dean M.

    2018-02-01

    The detonation of a sub-Chandrasekhar-mass white dwarf (WD) has emerged as one of the most promising Type Ia supernova (SN Ia) progenitor scenarios. Recent studies have suggested that the rapid transfer of a very small amount of helium from one WD to another is sufficient to ignite a helium shell detonation that subsequently triggers a carbon core detonation, yielding a “dynamically driven double-degenerate double-detonation” SN Ia. Because the helium shell that surrounds the core explosion is so minimal, this scenario approaches the limiting case of a bare C/O WD detonation. Motivated by discrepancies in previous literature and by a recent need for detailed nucleosynthetic data, we revisit simulations of naked C/O WD detonations in this paper. We disagree to some extent with the nucleosynthetic results of previous work on sub-Chandrasekhar-mass bare C/O WD detonations; for example, we find that a median-brightness SN Ia is produced by the detonation of a 1.0 {M}ȯ WD instead of a more massive and rarer 1.1 {M}ȯ WD. The neutron-rich nucleosynthesis in our simulations agrees broadly with some observational constraints, although tensions remain with others. There are also discrepancies related to the velocities of the outer ejecta and light curve shapes, but overall our synthetic light curves and spectra are roughly consistent with observations. We are hopeful that future multidimensional simulations will resolve these issues and further bolster the dynamically driven double-degenerate double-detonation scenario’s potential to explain most SNe Ia.

  18. Revisiting four scientific debates in ocean acidification research

    Directory of Open Access Journals (Sweden)

    A. J. Andersson

    2012-03-01

    Full Text Available In recent years, ocean acidification has gained continuously increasing attention from scientists and a number of stakeholders and has raised serious concerns about its effects on marine organisms and ecosystems. With the increase in interest, funding resources, and the number of scientific investigations focusing on this environmental problem, increasing amounts of data and results have been produced, and a progressively growing and more rigorous understanding of this problem has begun to develop. Nevertheless, there are still a number of scientific debates, and in some cases misconceptions, that keep reoccurring at a number of forums in various contexts. In this article, we revisit four of these topics that we think require further thoughtful consideration including: (1 surface seawater CO2 chemistry in shallow water coastal areas, (2 experimental manipulation of marine systems using CO2 gas or by acid addition, (3 net versus gross calcification and dissolution, and (4 CaCO3 mineral dissolution and seawater buffering. As a summation of these topics, we emphasize that: (1 many coastal environments experience seawater pCO2 that is significantly higher than expected from equilibrium with the atmosphere and is strongly linked to biological processes; (2 addition of acid, base or CO2 gas to seawater can all be useful techniques to manipulate seawater chemistry in ocean acidification experiments; (3 estimates of calcification or CaCO3 dissolution based on present techniques are measuring the net of gross calcification and dissolution; and (4 dissolution of metastable carbonate mineral phases will not produce sufficient alkalinity to buffer the pH and carbonate saturation state of shallow water environments on timescales of decades to hundreds of years to the extent that any potential negative effects on marine calcifiers will be avoided.

  19. The Lumbar Lordosis in Males and Females, Revisited.

    Directory of Open Access Journals (Sweden)

    Ori Hay

    Full Text Available Whether differences exist in male and female lumbar lordosis has been debated by researchers who are divided as to the nature of variations in the spinal curve, their origin, reasoning, and implications from a morphological, functional and evolutionary perspective. Evaluation of the spinal curvature is constructive in understanding the evolution of the spine, as well as its pathology, planning of surgical procedures, monitoring its progression and treatment of spinal deformities. The aim of the current study was to revisit the nature of lumbar curve in males and females.Our new automated method uses CT imaging of the spine to measure lumbar curvature in males and females. The curves extracted from 158 individuals were based on the spinal canal, thus avoiding traditional pitfalls of using bone features for curve estimation. The model analysis was carried out on the entire curve, whereby both local and global descriptors were examined in a single framework. Six parameters were calculated: segment length, curve length, curvedness, lordosis peak location, lordosis cranial peak height, and lordosis caudal peak height.Compared to males, the female spine manifested a statistically significant greater curvature, a caudally located lordotic peak, and greater cranial peak height. As caudal peak height is similar for males and females, the illusion of deeper lordosis among females is due partially to the fact that the upper part of the female lumbar curve is positioned more dorsally (more backwardly inclined.Males and females manifest different lumbar curve shape, yet similar amount of inward curving (lordosis. The morphological characteristics of the female spine were probably developed to reduce stress on the vertebral elements during pregnancy and nursing.

  20. Gastric schwannomas revisited: has precise preoperative diagnosis become feasible?

    Science.gov (United States)

    Fujiwara, Shinichi; Nakajima, Kiyokazu; Nishida, Toshirou; Takahashi, Tsuyoshi; Kurokawa, Yukinori; Yamasaki, Makoto; Miyata, Hiroshi; Takiguchi, Shuji; Mori, Masaki; Doki, Yuichiro

    2013-07-01

    Gastric schwannomas are not common but are clinically important in terms of differential diagnosis from other submucosal lesions. The precise preoperative diagnosis, however, has been challenging mainly owing to the lack of specific findings in conventional imaging studies. The aim of this study was to revisit the possibilities and limitations of modern preoperative diagnostic modalities for gastric schwannomas. Fourteen consecutive patients with a final pathological diagnosis of gastric schwannoma were retrospectively analyzed. Data included demographics, preoperative imaging studies/diagnosis, surgery, histopathology, and follow-up results. The series included 6 males and 8 females, with a median age of 49 years (range 26-68 years). No symptoms were presented, except for 1 patient with epigastric pain. The tumors were located in the upper (n = 5), middle (3), and lower stomach (6), with a median size of 41 mm (range 20-75 mm). Twelve schwannomas (86%) showed homogeneous enhancement on computed tomography. Ulceration was seen on endoscopy in 4 of 12 available cases (33%). Positron emission tomography was performed in the last 4 patients, showing fluorodeoxy-glucose uptake in all cases (100%). A preoperative diagnosis of schwannoma was not obtained in the majority of cases (13/14, 93%); only 1 case was correctly diagnosed, by endoscopic aspiration cytology. Laparoscopic partial gastrectomy was attempted and completed in 13 cases. The patients have been followed up for 4.7 years (range 2.1-20.3 years), with no recurrencesor metastases and acceptable gastrointestinal function. The precise preoperative diagnosis of gastric schwannomas remains difficult even with modern imaging studies. Surgery, therefore, should be positively considered for patients without a conclusive preoperative diagnosis.

  1. LARGE-SCALE FILAMENTARY STRUCTURES AROUND THE VIRGO CLUSTER REVISITED

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Suk; Rey, Soo-Chang; Lee, Youngdae; Lee, Woong; Chung, Jiwon [Department of Astronomy and Space Science, Chungnam National University, 99 Daehak-ro, Daejeon 305-764 (Korea, Republic of); Bureau, Martin [Sub-department of Astrophysics, Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Yoon, Hyein; Chung, Aeree [Department of Astronomy and Yonsei University Observatory, Yonsei University, Seoul 120-749 (Korea, Republic of); Jerjen, Helmut [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston, ACT 2611 (Australia); Lisker, Thorsten [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg (ZAH), Mönchhofstraße 12-14, D-69120 Heidelberg (Germany); Jeong, Hyunjin; Sung, Eon-Chang, E-mail: screy@cnu.ac.kr, E-mail: star4citizen@kasi.re.kr [Korea Astronomy and Space Science institute, 776 Daedeokdae-ro, Daejeon 305-348 (Korea, Republic of)

    2016-12-20

    We revisit the filamentary structures of galaxies around the Virgo cluster, exploiting a larger data set, based on the HyperLeda database, than previous studies. In particular, this includes a large number of low-luminosity galaxies, resulting in better sampled individual structures. We confirm seven known structures in the distance range 4  h {sup −1} Mpc < SGY < 16  h {sup −1} Mpc, now identified as filaments, where SGY is the axis of the supergalactic coordinate system roughly along the line of sight. The Hubble diagram of the filament galaxies suggests they are infalling toward the main body of the Virgo cluster. We propose that the collinear distribution of giant elliptical galaxies along the fundamental axis of the Virgo cluster is smoothly connected to two of these filaments (Leo II A and B). Behind the Virgo cluster (16  h {sup −1} Mpc < SGY < 27  h {sup −1} Mpc), we also identify a new filament elongated toward the NGC 5353/4 group (“NGC 5353/4 filament”) and confirm a sheet that includes galaxies from the W and M clouds of the Virgo cluster (“W–M sheet”). In the Hubble diagram, the NGC 5353/4 filament galaxies show infall toward the NGC 5353/4 group, whereas the W–M sheet galaxies do not show hints of gravitational influence from the Virgo cluster. The filamentary structures identified can now be used to better understand the generic role of filaments in the build-up of galaxy clusters at z  ≈ 0.

  2. Ecological caring-Revisiting the original ideas of caring science.

    Science.gov (United States)

    Dahlberg, Helena; Ranheim, Albertine; Dahlberg, Karin

    2016-01-01

    The aim of this empirically grounded philosophical paper is to explore the notion of holistic care with the intention to expand it into a notion of ecological care and in such a way revisit the original ideas of caring science. The philosophical analysis, driven by lifeworld theory and especially Merleau-Ponty's philosophy, is firmly rooted in contemporary clinical care. We used interview data from patients in a study at an anthroposophic clinic in Sweden, which forms part of an ecological community with, for example, ecological agriculture. The empirical study is analysed according to reflective lifeworld research. Starting from the fact that illness can be defined as a loss of homelikeness in the body and in the familiar world, our findings illustrate how ecological care helps the patient to once again find one's place in a world that is characterized by interconnectedness. The task of ecological care is thus not only to see the patient within a world of relationships but to help the patient find his/her place again, to understand himself/herself and the world anew . Ecological care is not only about fighting an illness, but also recognizes a patient from inside a world that s/he is affected by and affects, that s/he is understood and understands from. Such care tries to restore this connection by making possible the rhythmical movement as well as the space in-between activity and rest, between being cared for and actively involving oneself in one's recovery and between closing oneself off from the world and once again going out into it.

  3. Ecological caring—Revisiting the original ideas of caring science

    Directory of Open Access Journals (Sweden)

    Helena Dahlberg

    2016-11-01

    Full Text Available The aim of this empirically grounded philosophical paper is to explore the notion of holistic care with the intention to expand it into a notion of ecological care and in such a way revisit the original ideas of caring science. The philosophical analysis, driven by lifeworld theory and especially Merleau-Ponty's philosophy, is firmly rooted in contemporary clinical care. We used interview data from patients in a study at an anthroposophic clinic in Sweden, which forms part of an ecological community with, for example, ecological agriculture. The empirical study is analysed according to reflective lifeworld research. Starting from the fact that illness can be defined as a loss of homelikeness in the body and in the familiar world, our findings illustrate how ecological care helps the patient to once again find one's place in a world that is characterized by interconnectedness. The task of ecological care is thus not only to see the patient within a world of relationships but to help the patient find his/her place again, to understand himself/herself and the world anew. Ecological care is not only about fighting an illness, but also recognizes a patient from inside a world that s/he is affected by and affects, that s/he is understood and understands from. Such care tries to restore this connection by making possible the rhythmical movement as well as the space in-between activity and rest, between being cared for and actively involving oneself in one's recovery and between closing oneself off from the world and once again going out into it.

  4. Ecological caring—Revisiting the original ideas of caring science

    Science.gov (United States)

    Dahlberg, Helena; Ranheim, Albertine; Dahlberg, Karin

    2016-01-01

    The aim of this empirically grounded philosophical paper is to explore the notion of holistic care with the intention to expand it into a notion of ecological care and in such a way revisit the original ideas of caring science. The philosophical analysis, driven by lifeworld theory and especially Merleau-Ponty's philosophy, is firmly rooted in contemporary clinical care. We used interview data from patients in a study at an anthroposophic clinic in Sweden, which forms part of an ecological community with, for example, ecological agriculture. The empirical study is analysed according to reflective lifeworld research. Starting from the fact that illness can be defined as a loss of homelikeness in the body and in the familiar world, our findings illustrate how ecological care helps the patient to once again find one's place in a world that is characterized by interconnectedness. The task of ecological care is thus not only to see the patient within a world of relationships but to help the patient find his/her place again, to understand himself/herself and the world anew. Ecological care is not only about fighting an illness, but also recognizes a patient from inside a world that s/he is affected by and affects, that s/he is understood and understands from. Such care tries to restore this connection by making possible the rhythmical movement as well as the space in-between activity and rest, between being cared for and actively involving oneself in one's recovery and between closing oneself off from the world and once again going out into it. PMID:27914196

  5. Reconstitutions of mitochondrial inner membrane remodeling.

    Science.gov (United States)

    Barbot, Mariam; Meinecke, Michael

    2016-10-01

    Biological membranes exhibit function-related shapes, leading to a plethora of complex and beautiful cell and cell organellar morphologies. Most if not all of these structures have evolved for a particular physiological reason. The shapes of these structures are formed by physical forces that operate on membranes. To create particular shaped cells and cell organelles, membranes must undergo deformations which are determined by the structure and elasticity of the membrane and this process is most probable driven by proteins, lipids and/or interplay of both Zimmerberg and Kozlov (2006). Therefore, an important question of current cell biology in conjunction with physics and mathematics is to elucidate the functional cause for these different membrane morphologies as well as how they are formed. One of the most peculiar membrane shapes is observed in mitochondria. These organelles are surrounded by two membranes and especially the convoluted inner membrane displays a complex ultra-structure. A molecular understanding of how this membrane is shaped is missing to a large extent. Unlike membrane remodeling in classical curvature-dependent processes like clathrin-mediated endocytosis, mitochondria are most likely shaped by integral membrane proteins. Following, we will review the current knowledge of inner mitochondrial membrane architecture and discuss recent findings and advances in understanding the factors that shape this membrane. We will address pending questions especially with regard to the experimentally challenging nature of investigating membrane bending by hydrophobic integral membrane proteins. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Gas transmission through microporous membranes

    Science.gov (United States)

    Turel, Tacibaht

    2008-10-01

    An ideal protective clothing material should be a good barrier against harmful gases or vapor while allowing moisture vapor and air passage through the material. In the study and design of barrier materials, one of the critical issues is to balance these requirements, which may sometimes be mutually exclusive. Therefore it is critical to understand the macroscopic and microscopic structure of the attack mechanisms as well as the barrier materials and the transport phenomena in such systems. In this study, air and gas transmission through barrier systems consisting of porous membranes was investigated experimentally and a molecular-level probabilistic model was constructed to evaluate the effect of various parameters on the gas flow. The effect of membrane parameters such as porosity, pore size distribution, thickness as well as gas parameters such as molecule diameters were examined at single layer as well as multiple layers. To understand the gas behavior for harmful chemicals and to ensure safety during experimental studies, mimics of such gases were obtained which were comparable to the actual gases in shape, molecular weight and other chemical properties. Air, ammonia and several mimic gases of harmful chemical agents were studied. Beta-pinene was used as a mimic of sarin and prenol was used as a mimic of nitrogen mustard. Gas transmission experiments were conducted on polyester, nylon and polypropylene membranes each of which had different porosity and pore size distributions. Experiments were done at different pressure values and a comparison was made between permeability testing machines based on volumetric and manometric principles as to their ability to accommodate high permeability membranes. Physical and chemical adsorption of such gases on porous membranes was also investigated after the addition of active elements on the membrane surfaces which can interact with the gas molecules. An experimental setup was developed to measure concentration changes

  7. Impact of sludge flocs on membrane fouling in membrane bioreactors

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Niessen, Wolfgang; Jørgensen, Mads Koustrup

    of divalent ions such as calcium and iron. Furthermore, it was shown that the ratio between cations and EPS was important for the fouling potential of the sludge. A high ratio between divalent ions and EPS reduced membrane fouling as soluble EPS were adsorbed and bound within the sludge flocs. Strong compact...... flocs reduced membrane fouling, and more compact and strong flocs were formed if the concentration of divalent ions were high. Sludge was fractionated by centrifugation providing supernatant with soluble EPS and colloidal particles but without flocs. Filtration test on untreated sludge and supernatant...

  8. Zwitterionic materials for antifouling membrane surface construction.

    Science.gov (United States)

    He, Mingrui; Gao, Kang; Zhou, Linjie; Jiao, Zhiwei; Wu, Mengyuan; Cao, Jialin; You, Xinda; Cai, Ziyi; Su, Yanlei; Jiang, Zhongyi

    2016-08-01

    Membrane separation processes are often perplexed by severe and ubiquitous membrane fouling. Zwitterionic materials, keeping electric neutrality with equivalent positive and negative charged groups, are well known for their superior antifouling properties and have been broadly utilized to construct antifouling surfaces for medical devices, biosensors and marine coatings applications. In recent years, zwitterionic materials have been more and more frequently utilized for constructing antifouling membrane surfaces. In this review, the antifouling mechanisms of zwitterionic materials as well as their biomimetic prototypes in cell membranes will be discussed, followed by the survey of common approaches to incorporate zwitterionic materials onto membrane surfaces including surface grafting, surface segregation, biomimetic adhesion, surface coating and so on. The potential applications of these antifouling membranes are also embedded. Finally, we will present a brief perspective on the future development of zwitterionic materials modified antifouling membranes. Membrane fouling is a severe problem hampering the application of membrane separation technology. The properties of membrane surfaces play a critical role in membrane fouling and antifouling behavior/performance. Antifouling membrane surface construction has evolved as a hot research issue for the development of membrane processes. Zwitterionic modification of membrane surfaces has been recognized as an effective strategy to resist membrane fouling. This review summarizes the antifouling mechanisms of zwitterionic materials inspired by cell membranes as well as the popular approaches to incorporate them onto membrane surfaces. It can help form a comprehensive knowledge about the principles and methods of modifying membrane surfaces with zwitterionic materials. Finally, we propose the possible future research directions of zwitterionic materials modified antifouling membranes. Copyright © 2016 Acta Materialia Inc

  9. Tocopherol Activity Correlates with its Location in a Membrane: A New Perspective on the Anti-Oxidant Vitamin E

    Energy Technology Data Exchange (ETDEWEB)

    Marquardt, Drew [Brock University, St. Catharines, ON, Canada; Williams, Justin [Indiana University and Purdue University; Kucerka, Norbert [Canadian Neutron Beam Centre and Comelius University (Slovakia); Atkinson, Jeffrey [Brock University, St. Catharines, ON, Canada; Wassall, Stephen [Indiana University and Purdue University; Katsaras, John [ORNL; Harroun, Thad [Brock University, St. Catharines, ON, Canada

    2013-01-01

    We show evidence of an antioxidant mechanism for vitamin E which correlates strongly with its physical location in a model lipid bilayer. This data addresses the overlooked problem of the physical distance between the vitamin's reducing hydrogen and lipid acyl chain radicals. Our combined data from neutron diffraction, NMR and UV spectroscopy experiments, all suggest that reduction of reactive oxygen species and lipid radicals occurs specifically at the membrane's hydrophobic-hydrophilic interface. The latter is possible when the acyl chain snorkels to the interface from the hydrocarbon matrix. Moreover, not all model lipids are equal in this regard, as indicated by the small differences in vitamin's location. The present result is a clear example of the importance of lipid diversity in controlling the dynamic structural properties of biological membranes. Importantly, our results suggest that measurements of aToc oxidation kinetics, and its products, should be revisited by taking into consideration the physical properties of the membrane in which the vitamin resides.

  10. Application of OLM Techniques to Enhance the Calibration and Maintenance Practices In ESSalam Nuclear Research Reactor

    International Nuclear Information System (INIS)

    Touati, S.; Messai, A.; Abdellani, I.

    2013-06-01

    As a beginning, we consider the case of the coolant pumps (electrical motor and a driven pump) which are critical part in all nuclear facility and are an element in safety processes requiring highest reliability condition monitoring. In order to determine their operational characteristics, degradation mechanisms, and failure modes, we will use some on-line acquired parameters such as: the vibration data collection, temperature measurement, ...etc. Through adequate analysis, including artificial intelligence techniques and frequency analysis, performed on-line on these recorded data, we will be able to establish a predictive maintenance program for crucial rotating equipment in our research reactor. (authors)

  11. 75 FR 27366 - OLMS Listens: Office of Labor-Management Standards Stakeholder Meeting

    Science.gov (United States)

    2010-05-14

    ... of Labor, Frances Perkins Building Auditorium, 200 Constitution Avenue, NW., Washington, DC 20210. To..., as articulated in the LMRDA Interpretative Manual and in a Federal Register notice published on April... Labor, Frances Perkins Building Auditorium, 200 Constitution Avenue, NW., Washington, DC 20210. All...

  12. Nanoengineered membranes for controlled transport

    Science.gov (United States)

    Doktycz, Mitchel J [Oak Ridge, TN; Simpson, Michael L [Knoxville, TN; McKnight, Timothy E [Greenback, TN; Melechko, Anatoli V [Oak Ridge, TN; Lowndes, Douglas H [Knoxville, TN; Guillorn, Michael A [Knoxville, TN; Merkulov, Vladimir I [Oak Ridge, TN

    2010-01-05

    A nanoengineered membrane for controlling material transport (e.g., molecular transport) is disclosed. The membrane includes a substrate, a cover definining a material transport channel between the substrate and the cover, and a plurality of fibers positioned in the channel and connected to an extending away from a surface of the substrate. The fibers are aligned perpendicular to the surface of the substrate, and have a width of 100 nanometers or less. The diffusion limits for material transport are controlled by the separation of the fibers. In one embodiment, chemical derivitization of carbon fibers may be undertaken to further affect the diffusion limits or affect selective permeability or facilitated transport. For example, a coating can be applied to at least a portion of the fibers. In another embodiment, individually addressable carbon nanofibers can be integrated with the membrane to provide an electrical driving force for material transport.

  13. Experimental approaches to membrane thermodynamics

    DEFF Research Database (Denmark)

    Westh, Peter

    2009-01-01

    Thermodynamics describes a system on the macroscopic scale, yet it is becoming an important tool for the elucidation of many specific molecular aspects of membrane properties. In this note we discuss this application of thermodynamics, and give a number of examples on how thermodynamic measuremen...... have contributed to the understanding of specific membrane phenomena. We mainly focus on non-specific interactions of bilayers and small molecules (water and solutes) in the surrounding solvent, and the changes in membrane properties they bring about. Differences between thermodynamic...... and stoichiometric (structural) definitions of non-specific binding or partitioning are emphasized, and it is concluded that this distinction is important for weak, but not for strong, interactions....

  14. Mesoscopic models of biological membranes

    DEFF Research Database (Denmark)

    Venturoli, M.; Sperotto, Maria Maddalena; Kranenburg, M.

    2006-01-01

    Phospholipids are the main components of biological membranes and dissolved in water these molecules self-assemble into closed structures, of which bilayers are the most relevant from a biological point of view. Lipid bilayers are often used, both in experimental and by theoretical investigations......, as model systems to understand the fundamental properties of biomembranes. The properties of lipid bilayers can be studied at different time and length scales. For some properties it is sufficient to envision a membrane as an elastic sheet, while for others it is important to take into account the details...... to coarse grain a biological membrane. The conclusion of this comparison is that there can be many valid different strategies, but that the results obtained by the various mesoscopic models are surprisingly consistent. A second objective of this review is to illustrate how mesoscopic models can be used...

  15. Multilayered Magnetic Gelatin Membrane Scaffolds

    Science.gov (United States)

    Samal, Sangram K.; Goranov, Vitaly; Dash, Mamoni; Russo, Alessandro; Shelyakova, Tatiana; Graziosi, Patrizio; Lungaro, Lisa; Riminucci, Alberto; Uhlarz, Marc; Bañobre-López, Manuel; Rivas, Jose; Herrmannsdörfer, Thomas; Rajadas, Jayakumar; De Smedt, Stefaan; Braeckmans, Kevin; Kaplan, David L.; Dediu, V. Alek

    2016-01-01

    A versatile approach for the design and fabrication of multilayer magnetic scaffolds with tunable magnetic gradients is described. Multilayer magnetic gelatin membrane scaffolds with intrinsic magnetic gradients were designed to encapsulate magnetized bioagents under an externally applied magnetic field for use in magnetic-field-assisted tissue engineering. The temperature of the individual membranes increased up to 43.7 °C under an applied oscillating magnetic field for 70 s by magnetic hyperthermia, enabling the possibility of inducing a thermal gradient inside the final 3D multilayer magnetic scaffolds. On the basis of finite element method simulations, magnetic gelatin membranes with different concentrations of magnetic nanoparticles were assembled into 3D multilayered scaffolds. A magnetic-gradient-controlled distribution of magnetically labeled stem cells was demonstrated in vitro. This magnetic biomaterial–magnetic cell strategy can be expanded to a number of different magnetic biomaterials for various tissue engineering applications. PMID:26451743

  16. Membrane interaction of retroviral Gag proteins

    Directory of Open Access Journals (Sweden)

    Robert Alfred Dick

    2014-04-01

    Full Text Available Assembly of an infectious retroviral particle relies on multimerization of the Gag polyprotein at the inner leaflet of the plasma membrane. The three domains of Gag common to all retroviruses-- MA, CA, and NC-- provide the signals for membrane binding, assembly, and viral RNA packaging, respectively. These signals do not function independently of one another. For example, Gag multimerization enhances membrane binding and is more efficient when NC is interacting with RNA. MA binding to the plasma membrane is governed by several principles, including electrostatics, recognition of specific lipid head groups, hydrophobic interactions, and membrane order. HIV-1 uses many of these principles while Rous sarcoma virus (RSV appears to use fewer. This review describes the principles that govern Gag interactions with membranes, focusing on RSV and HIV-1 Gag. The review also defines lipid and membrane behavior, and discusses the complexities in determining how lipid and membrane behavior impact Gag membrane binding.

  17. Synthetic Biomimetic Membranes and Their Sensor Applications

    Directory of Open Access Journals (Sweden)

    Young-Rok Kim

    2012-07-01

    Full Text Available Synthetic biomimetic membranes provide biological environments to membrane proteins. By exploiting the central roles of biological membranes, it is possible to devise biosensors, drug delivery systems, and nanocontainers using a biomimetic membrane system integrated with functional proteins. Biomimetic membranes can be created with synthetic lipids or block copolymers. These amphiphilic lipids and polymers self-assemble in an aqueous solution either into planar membranes or into vesicles. Using various techniques developed to date, both planar membranes and vesicles can provide versatile and robust platforms for a number of applications. In particular, biomimetic membranes with modified lipids or functional proteins are promising platforms for biosensors. We review recent technologies used to create synthetic biomimetic membranes and their engineered sensors applications.

  18. Uranium preconcentration from seawater using adsorptive membranes

    International Nuclear Information System (INIS)

    Das, Sadananda; Pandey, A.K.; Manchanda, V.K.; Athawale, A.A.

    2009-01-01

    Uranium recovery from bio-aggressive but lean feed like seawater is a challenging problem as it requires in situ preconcentration of uranium in presence of huge excess of competing ions with fast sorption kinetics. In our laboratory, widely used amidoxime membrane (AO-membrane) was evaluated for uranium sorption under seawater conditions. This study indicated that AO-membrane was inherently slow because of the complexation chemistry involved in transfer of U(VI) from (UO 2 (CO 3 ) 3 ) 4 - to AO sites in membrane. In order to search better options, several chemical compositions of membrane were scanned for their efficacy for uranium preconcentration from seawater, and concluded that EGMP-membrane offers several advantages over AO-membrane. In this paper, the comparison of EGMP-membrane with AO-membrane for uranium sorption under seawater conditions has been reviewed. (author)

  19. Membrane bending by protein-protein crowding.

    Science.gov (United States)

    Stachowiak, Jeanne C; Schmid, Eva M; Ryan, Christopher J; Ann, Hyoung Sook; Sasaki, Darryl Y; Sherman, Michael B; Geissler, Phillip L; Fletcher, Daniel A; Hayden, Carl C

    2012-09-01

    Curved membranes are an essential feature of dynamic cellular structures, including endocytic pits, filopodia protrusions and most organelles. It has been proposed that specialized proteins induce curvature by binding to membranes through two primary mechanisms: membrane scaffolding by curved proteins or complexes; and insertion of wedge-like amphipathic helices into the membrane. Recent computational studies have raised questions about the efficiency of the helix-insertion mechanism, predicting that proteins must cover nearly 100% of the membrane surface to generate high curvature, an improbable physiological situation. Thus, at present, we lack a sufficient physical explanation of how protein attachment bends membranes efficiently. On the basis of studies of epsin1 and AP180, proteins involved in clathrin-mediated endocytosis, we propose a third general mechanism for bending fluid cellular membranes: protein-protein crowding. By correlating membrane tubulation with measurements of protein densities on membrane surfaces, we demonstrate that lateral pressure generated by collisions between bound proteins drives bending. Whether proteins attach by inserting a helix or by binding lipid heads with an engineered tag, protein coverage above ~20% is sufficient to bend membranes. Consistent with this crowding mechanism, we find that even proteins unrelated to membrane curvature, such as green fluorescent protein (GFP), can bend membranes when sufficiently concentrated. These findings demonstrate a highly efficient mechanism by which the crowded protein environment on the surface of cellular membranes can contribute to membrane shape change.

  20. Mesoscopic models of biological membranes

    DEFF Research Database (Denmark)

    Venturoli, M.; Sperotto, Maria Maddalena; Kranenburg, M.

    2006-01-01

    Phospholipids are the main components of biological membranes and dissolved in water these molecules self-assemble into closed structures, of which bilayers are the most relevant from a biological point of view. Lipid bilayers are often used, both in experimental and by theoretical investigations...... to coarse grain a biological membrane. The conclusion of this comparison is that there can be many valid different strategies, but that the results obtained by the various mesoscopic models are surprisingly consistent. A second objective of this review is to illustrate how mesoscopic models can be used...

  1. Robust mixed conducting membrane structure

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention provides a membrane structure, comprising in said order a first electronically conducting layer, an ionically conducting layer, and a second electronically conducting layer, characterized in that the first and second electronically conducting layers are internally short...... circuited. The present invention further provides a method of producing the above membrane structure, comprising the steps of : providing a ionically conducting layer; applying at least one layer of electronically conducting material on each side of said ionically conducting layer; sintering the multilayer...... structure; and impregnating the electronically conducting layers with a catalyst material or catalyst precursor material....

  2. Membrane processes in nuclear technologies

    International Nuclear Information System (INIS)

    Zakrzewska-Trznadel, G.

    2006-01-01

    The treatment of radioactive wastes is necessary taking into account the potential hazard of radioactive substances to human health and surrounding environment. The choice of appropriate technology depends on capital and operational costs, wastes amount and their characteristics, appointed targets of the process, e.g. the values of decontamination factors and volume reduction coefficients. The conventional technologies applied for radioactive waste processing, such as precipitation coupled with sedimentation, ion exchange and evaporation have many drawbacks. These include high energy consumption and formation of secondary wastes, e.g. the sludge from sediment tanks, spent ion exchange adsorbents and regeneration solutions. There are also many limitations of such processes, i.e. foaming and drop entrainment in evaporators, loses of solvents and production of secondary wastes in solvent extraction or bed clogging in ion exchange columns. Membrane processes as the newest achievement of the process engineering can successfully supersede many non-effective, out-of-date methods. But in some instances they can also complement these methods whilst improving the parameters of effluents and purification economy. This monograph presents own research data on the application of recent achievements in the area of membrane processes for solving selected problems in nuclear technology. Relatively big space was devoted to the use of membrane processing of low and intermediate radioactive liquid wastes because of numerous applications of these processes in nuclear centres over the world and also because of the interests of the author that was reflected by her recent research projects and activity. This work presents a review on the membrane methods recently introduced into the nuclear technology against the background of the other, commonly applied separation techniques, with indications of the possibilities and prospects for their further developments. Particular attention was paid

  3. Large scale biomimetic membrane arrays

    DEFF Research Database (Denmark)

    Hansen, Jesper Søndergaard; Perry, Mark; Vogel, Jörg

    2009-01-01

    To establish planar biomimetic membranes across large scale partition aperture arrays, we created a disposable single-use horizontal chamber design that supports combined optical-electrical measurements. Functional lipid bilayers could easily and efficiently be established across CO2 laser micro...... peptides and proteins. Next, we tested the scalability of the biomimetic membrane design by establishing lipid bilayers in rectangular 24 x 24 and hexagonal 24 x 27 aperture arrays, respectively. The results presented show that the design is suitable for further developments of sensitive biosensor assays...

  4. Polymeric and Lipid Membranes-From Spheres to Flat Membranes and vice versa.

    Science.gov (United States)

    Saveleva, Mariia S; Lengert, Ekaterina V; Gorin, Dmitry A; Parakhonskiy, Bogdan V; Skirtach, Andre G

    2017-08-15

    Membranes are important components in a number of systems, where separation and control of the flow of molecules is desirable. Controllable membranes represent an even more coveted and desirable entity and their development is considered to be the next step of development. Typically, membranes are considered on flat surfaces, but spherical capsules possess a perfect "infinite" or fully suspended membranes. Similarities and transitions between spherical and flat membranes are discussed, while applications of membranes are also emphasized.

  5. Membrane potentials of membranes with fixed ionic sites

    NARCIS (Netherlands)

    van den Berg, Albert; van der Wal, P.D.; van der Wal, P.D.; Skowronska-ptasinska, M.; Sudhölter, E.J.R.; Sudholter, Ernst; Bergveld, Piet; Reinhoudt, David

    1990-01-01

    A theoretical model has been developed to simulate the formation of a membrane potential as a function of physically accessible parameters. The description is an extension of the well-known Teorell-Meyer-Sievers (TMS) model, now including free and fixed ionic sites and free and fixed neutral

  6. Efficient preparation and analysis of membrane and membrane protein systems

    Czech Academy of Sciences Publication Activity Database

    Javanainen, M.; Martinez-Seara, Hector

    2016-01-01

    Roč. 1858, č. 10 (2016), s. 2468-2482 ISSN 0005-2736 Institutional support: RVO:61388963 Keywords : tools and software * membrane building * protein insertion * molecular dynamics * lipid bilayer Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.498, year: 2016

  7. STUDI MEMBRAN KITOSAN DARI KULIT LOBSTER BAMBU SEBAGAI MEMBRAN FILTRASI

    Directory of Open Access Journals (Sweden)

    Ni Nyoman Putri Windari

    2016-02-01

    Full Text Available The study of the extraction and characterization of chitosan from skin waste of Bamboo Lobster (Panulirus versicolor has been done. Chitosan is extracted using conventional method, namely the initial process: cleaning and drying (pretreatment, demineralization, deproteination, and deacetylation. The chitosan obtained has been used to prepare chitosan membrane 2% with acetic acid 1% as solvent. The membrane prepared by phase inversion method withprecipitation through solvent evaporation. The prepared membranes were characterized by FTIR spectrophotometer, Nova 1200e by BJH method and filtration method. The results obtained that degree of deacetylation (DD of chitosan is 70.016%. The thickness of the membrane is 0.361 mm. The FTIR spectra show that functional groups obtained are -NH, -CH, C=O, C-O and -CN. From BJH method obtained that the pore radius is 1.69 nm and pore density is 8.95 x 105pores/m3. From the filtration method obtained that at each pressure, 80-85 kPa and 90-100 kPa, the PWF values are 381.232 and 454.545 L/m2.h, respectively.

  8. Membrane distillation : a new approach using composite membranes

    NARCIS (Netherlands)

    Franken, Antonius Christianus Maria

    1988-01-01

    In this thesis several aspects of the membrane distillation process and the thermally driven pervaporation process have been described. Both processes differ essentially from each other as far as their mechanism of separation and their applicability is concerned. From a practical point of view,

  9. Diffusion of Integral Membrane Proteins in Protein-Rich Membranes

    Czech Academy of Sciences Publication Activity Database

    Javanainen, M.; Martinez-Seara, Hector; Metzler, R.; Vattulainen, I.

    2017-01-01

    Roč. 8, č. 17 (2017), s. 4308-4313 ISSN 1948-7185 R&D Projects: GA ČR(CZ) GBP208/12/G016 Institutional support: RVO:61388963 Keywords : giant unilamellar vesicles * single-molecule tracking * lipid bilayer membranes Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 9.353, year: 2016

  10. Convergence of lateral dynamic measurements in the plasma membrane of live cells from single particle tracking and STED-FCS

    Science.gov (United States)

    Lagerholm, B. Christoffer; Andrade, Débora M.; Clausen, Mathias P.; Eggeling, Christian

    2017-02-01

    Fluorescence correlation spectroscopy (FCS) in combination with the super-resolution imaging method STED (STED-FCS), and single-particle tracking (SPT) are able to directly probe the lateral dynamics of lipids and proteins in the plasma membrane of live cells at spatial scales much below the diffraction limit of conventional microscopy. However, a major disparity in interpretation of data from SPT and STED-FCS remains, namely the proposed existence of a very fast (unhindered) lateral diffusion coefficient, ⩾5 µm2 s-1, in the plasma membrane of live cells at very short length scales, ≈⩽ 100 nm, and time scales, ≈1-10 ms. This fast diffusion coefficient has been advocated in several high-speed SPT studies, for lipids and membrane proteins alike, but the equivalent has not been detected in STED-FCS measurements. Resolving this ambiguity is important because the assessment of membrane dynamics currently relies heavily on SPT for the determination of heterogeneous diffusion. A possible systematic error in this approach would thus have vast implications in this field. To address this, we have re-visited the analysis procedure for SPT data with an emphasis on the measurement errors and the effect that these errors have on the measurement outputs. We subsequently demonstrate that STED-FCS and SPT data, following careful consideration of the experimental errors of the SPT data, converge to a common interpretation which for the case of a diffusing phospholipid analogue in the plasma membrane of live mouse embryo fibroblasts results in an unhindered, intra-compartment, diffusion coefficient of  ≈0.7-1.0 µm2 s-1, and a compartment size of about 100-150 nm.

  11. Solvent-resistant microporous polymide membranes

    Science.gov (United States)

    Miller, Warren K.; McCray, Scott B.; Friesen, Dwayne T.

    1998-01-01

    An asymmetric microporous membrane with exceptional solvent resistance and highly desirable permeability is disclosed. The membrane is made by a solution-casting or solution-spinning process from a copolyamic acid comprising the condensation reaction product in a solvent of at least three reactants selected from certain diamines and dianhydrides and post-treated to imidize and in some cases cross-link the copolyamic acid. The membrane is useful as an uncoated membrane for ultrafiltration, microfiltration, and membrane contactor applications, or may be used as a support for a permselective coating to form a composite membrane useful in gas separations, reverse osmosis, nanofiltration, pervaporation, or vapor permeation.

  12. 3D Membrane Imaging and Porosity Visualization

    KAUST Repository

    Sundaramoorthi, Ganesh

    2016-03-03

    Ultrafiltration asymmetric porous membranes were imaged by two microscopy methods, which allow 3D reconstruction: Focused Ion Beam and Serial Block Face Scanning Electron Microscopy. A new algorithm was proposed to evaluate porosity and average pore size in different layers orthogonal and parallel to the membrane surface. The 3D-reconstruction enabled additionally the visualization of pore interconnectivity in different parts of the membrane. The method was demonstrated for a block copolymer porous membrane and can be extended to other membranes with application in ultrafiltration, supports for forward osmosis, etc, offering a complete view of the transport paths in the membrane.

  13. A Model for Membrane Fusion

    Science.gov (United States)

    Ngatchou, Annita

    2010-01-01

    Pheochromocytoma is a tumor of the adrenal gland which originates from chromaffin cells and is characterized by the secretion of excessive amounts of neurotransmitter which lead to high blood pressure and palpitations. Pheochromocytoma contain membrane bound granules that store neurotransmitter. The release of these stored molecules into the extracellular space occurs by fusion of the granule membrane with the cell plasma membrane, a process called exocytosis. The molecular mechanism of this membrane fusion is not well understood. It is proposed that the so called SNARE proteins [1] are the pillar of vesicle fusion as their cleavage by clostridial toxin notably, Botulinum neurotoxin and Tetanus toxin abrogate the secretion of neurotransmitter [2]. Here, I describe how physical principles are applied to a biological cell to explore the role of the vesicle SNARE protein synaptobrevin-2 in easing granule fusion. The data presented here suggest a paradigm according to which the movement of the C-terminal of synaptobrevin-2 disrupts the lipid bilayer to form a fusion pore through which molecules can exit.

  14. Membrane Trafficking and Vesicle Fusion

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 5. Membrane Trafficking and Vesicle Fusion: Post-Palade Era Researchers Win the Nobel Prize. Riddhi Atul Jani Subba Rao Gangi Setty. General Article Volume 19 Issue 5 May 2014 pp 421-445 ...

  15. Stability of supported liquid membranes

    NARCIS (Netherlands)

    Neplenbroek, Antonius Maria

    1989-01-01

    This thesis deals with the stability of supported liquid membranes (SLMs). The use of SLMs, in which an extraction liquid containing a carrier is immobilized in the pores of a microporous support, has recently been introduced as a promising new separation technique. Some advantages ascribed to this

  16. Membrane adsorbers : development and applications

    NARCIS (Netherlands)

    Avramescu, M.E.

    2002-01-01

    Bioaffinity separation principally asks for membranes that show a good compatibility to the targeted biological fluids, provide coupling sites for (bio)ligands and posses a hydrophilic surface to reduce non-specific adsorption caused by hydrophobic atraction. Due to its good blood compatibility and

  17. Preparation of gas selective membranes

    Science.gov (United States)

    Kulprathipanja, Santi; Kulkarni, Sudhir S.; Funk, Edward W.

    1988-01-01

    Gas separation membranes which possess improved characteristics as exemplified by selectivity and flux may be prepared by coating a porous organic polymer support with a solution or emulsion of a plasticizer and an organic polymer, said coating being effected at subatmospheric pressures in order to increase the penetration depth of the coating material.

  18. The Plasma Membrane Calcium Pump

    Science.gov (United States)

    Rasmussen, H.

    1983-01-01

    Three aspect of cellular calcium metabolism in animal cells was discussed including the importance of the plasma membrane in calcium homeostasis, experiments dealing with the actual mechanism of the calcium pump, and the function of the pump in relationship to the mitochondria and to the function of calmodulin in the intact cell.

  19. Guanidinium Pairing Facilitates Membrane Translocation

    Czech Academy of Sciences Publication Activity Database

    Allolio, Christoph; Baxová, Katarína; Vazdar, M.; Jungwirth, Pavel

    2016-01-01

    Roč. 120, č. 1 (2016), s. 143-153 ISSN 1520-6106 R&D Projects: GA ČR GA13-06181S Institutional support: RVO:61388963 Keywords : ab initio molecular dynamics * guanidinium * like charge pairing * membrane Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.177, year: 2016

  20. Comparative antioxidant capacity, membrane stabilization ...

    African Journals Online (AJOL)

    Comparative antioxidant capacity, membrane stabilization, polyphenol composition and cytotoxicity of the leaf and stem of Cissus multistriata. ... standard anti-inflammatory drug (Indomethacin) used. The extracts are less toxic to the cell (Arthenia salina) with their LC/EC50 higher than that of standard potassium dichromate ...

  1. Challenges in Commercializing Biomimetic Membranes.

    Science.gov (United States)

    Perry, Mark; Madsen, Steen Ulrik; Jørgensen, Tine; Braekevelt, Sylvie; Lauritzen, Karsten; Hélix-Nielsen, Claus

    2015-11-05

    The discovery of selective water channel proteins-aquaporins-has prompted growing interest in using these proteins, as the building blocks for designing new types of membranes. However, as with any other new and potentially disruptive technology, barriers for successful market entry exist. One category includes customer-related barriers, which can be influenced to some extent. Another category includes market-technical-related barriers, which can be very difficult to overcome by an organization/company aiming at successfully introducing their innovation on the market-in particular if both the organization and the technology are at early stages. Often, one faces barriers from both these categories at the same time, which makes it necessary to gain insight of the particular market when introducing a new innovative product. In this review we present the basic concepts and discuss some of these barriers and challenges associated with introducing biomimetic aquaporin membranes. These include technical issues in membrane production and product testing. Then we discuss possible business models for introducing new technologies in general, followed by a presentation of beach-head market segments relevant for biomimetic aquaporin membranes.

  2. PREMATURE RUPTURE OF THE MEMBRANES*

    African Journals Online (AJOL)

    In patients presenting with premature rupture of the membranes there are two factors which influence the foetal morbidity and mortality. These factors are prema- turity and intra-uterine infection. The purpose of this analysis was to elucidate which factor carried the greater risk to the foetus. Recently there has been a spate of.

  3. Extracorporeal membrane oxygenation (ECMO) | Richards ...

    African Journals Online (AJOL)

    Extracorporeal membrane oxygenation (ECMO) is increasingly being employed in South African intensive care units for the management of patients with refractory hypoxaemia and for haemodynamic support, particularly following cardiothoracic procedures. ECMO is expensive, however, and there is a danger that this ...

  4. Basement membrane proteoglycans and development

    DEFF Research Database (Denmark)

    Couchman, J R; Abrahamson, D R; McCarthy, K J

    1993-01-01

    -CSPG was only strongly expressed in the vasculature invading late comma stage glomeruli, and later in presumptive and mature Bowman's capsule. Over the first six to eight weeks, the capillary basement membranes contained BM-CSPG, but in gradually decreasing amounts until it became completely undetectable...

  5. Osmosis and the Marvelous Membrane.

    Science.gov (United States)

    Cocanour, Barbara; Bruce, Alease S.

    1985-01-01

    Shows how the natural membrane of a decalcified chicken egg can demonstrate the principle of osmosis within a single class period. Various glucose and saline solutions used, periods of time, physiological effects experiments, and correction for differences in initial weights are noted. (DH)

  6. Intelligent Membranes: Dream or Reality?

    Science.gov (United States)

    Gugliuzza, Annarosa

    2013-07-15

    Intelligent materials are claimed to overcome current drawbacks associated with the attainment of high standards of life, health, security and defense. Membrane-based sensors represent a category of smart systems capable of providing a large number of benefits to different markets of textiles, biomedicine, environment, chemistry, agriculture, architecture, transport and energy. Intelligent membranes can be characterized by superior sensitivity, broader dynamic range and highly sophisticated mechanisms of autorecovery. These prerogatives are regarded as the result of multi-compartment arrays, where complementary functions can be accommodated and well-integrated. Based on the mechanism of "sense to act", stimuli-responsive membranes adapt themselves to surrounding environments, producing desired effects such as smart regulation of transport, wetting, transcription, hydrodynamics, separation, and chemical or energy conversion. Hopefully, the design of new smart devices easier to manufacture and assemble can be realized through the integration of sensing membranes with wireless networks, looking at the ambitious challenge to establish long-distance communications. Thus, the transfer of signals to collecting systems could allow continuous and real-time monitoring of data, events and/or processes.

  7. Challenges in Commercializing Biomimetic Membranes

    Directory of Open Access Journals (Sweden)

    Mark Perry

    2015-11-01

    Full Text Available The discovery of selective water channel proteins—aquaporins—has prompted growing interest in using these proteins, as the building blocks for designing new types of membranes. However, as with any other new and potentially disruptive technology, barriers for successful market entry exist. One category includes customer-related barriers, which can be influenced to some extent. Another category includes market-technical-related barriers, which can be very difficult to overcome by an organization/company aiming at successfully introducing their innovation on the market—in particular if both the organization and the technology are at early stages. Often, one faces barriers from both these categories at the same time, which makes it necessary to gain insight of the particular market when introducing a new innovative product. In this review we present the basic concepts and discuss some of these barriers and challenges associated with introducing biomimetic aquaporin membranes. These include technical issues in membrane production and product testing. Then we discuss possible business models for introducing new technologies in general, followed by a presentation of beach-head market segments relevant for biomimetic aquaporin membranes.

  8. Comparative antioxidant capacity, membrane stabilization ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-03

    Sep 3, 2008 ... In this present study, a comparative evaluation of the antioxidant capacities, phenol and polyphenol composition, membrane stabilization, and cytotoxicity to brine shrimps (Arthemia salina) of the leaf and stem extracts of Cissus multistriata were carried out. 2,2- Diphenyl-1-picryl hydrazyl (DPPH) radical.

  9. Membrane Trafficking and Vesicle Fusion

    Indian Academy of Sciences (India)

    IAS Admin

    investigators were awarded the Nobel Prize in Physiology or. Medicine in 2013. Introduction. Membrane Transport: In the eukaryotic cell, a majority of proteins are made in the cytosol. But the transmembrane and secretory proteins are synthesized in an organelle called the rough endoplasmic reticulum (ER). These proteins ...

  10. Membrane microdomains in immunoreceptor signaling

    Czech Academy of Sciences Publication Activity Database

    Hořejší, Václav; Hrdinka, Matouš

    2014-01-01

    Roč. 588, č. 15 (2014), s. 2392-2397 ISSN 0014-5793 R&D Projects: GA ČR(CZ) GBP302/12/G101 Institutional support: RVO:68378050 Keywords : membrane raft * microdomain * immunoreceptor Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.169, year: 2014

  11. Intelligent Membranes: Dream or Reality?

    Directory of Open Access Journals (Sweden)

    Annarosa Gugliuzza

    2013-07-01

    Full Text Available Intelligent materials are claimed to overcome current drawbacks associated with the attainment of high standards of life, health, security and defense. Membrane-based sensors represent a category of smart systems capable of providing a large number of benefits to different markets of textiles, biomedicine, environment, chemistry, agriculture, architecture, transport and energy. Intelligent membranes can be characterized by superior sensitivity, broader dynamic range and highly sophisticated mechanisms of autorecovery. These prerogatives are regarded as the result of multi-compartment arrays, where complementary functions can be accommodated and well-integrated. Based on the mechanism of “sense to act”, stimuli-responsive membranes adapt themselves to surrounding environments, producing desired effects such as smart regulation of transport, wetting, transcription, hydrodynamics, separation, and chemical or energy conversion. Hopefully, the design of new smart devices easier to manufacture and assemble can be realized through the integration of sensing membranes with wireless networks, looking at the ambitious challenge to establish long-distance communications. Thus, the transfer of signals to collecting systems could allow continuous and real-time monitoring of data, events and/or processes.

  12. The Angular Momentum of Baryons and Dark Matter Halos Revisited

    Science.gov (United States)

    Kimm, Taysun; Devriendt, Julien; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A.; Dubois, Yohan

    2011-01-01

    Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive-mesh refinement (AMR), we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole. At high redshift, freshly accreted gas rapidly streams into the central region of the halo, directly depositing this large amount of angular momentum within a sphere of radius r = 0.1R(sub vir). In contrast, dark matter particles pass through the central region unscathed, and a fraction of them ends up populating the outer regions of the halo (r/R(sub vir) > 0.1), redistributing angular momentum in the process. As a result, large-scale motions of the cosmic web have to be considered as the origin of gas angular momentum rather than its virialised dark matter halo host. This generic result holds for halos of all masses at all redshifts, as radiative cooling ensures that a significant fraction of baryons remain trapped at the centre of the halos. Despite this injection of angular momentum enriched gas, we predict an amount for stellar discs which is in fair agreement with observations at z=0. This arises because the total specific angular momentum of the baryons (gas and stars) remains close to that of dark matter halos. Indeed, our simulations indicate that any differential loss of angular momentum amplitude between the two components is minor even though dark matter halos continuously lose between half and two-thirds of their specific angular momentum modulus as they evolve. In light of our results, a substantial revision of the standard theory of disc formation seems to be required. We propose a new scenario where gas efficiently carries the angular momentum generated

  13. SU-E-I-43: Photoelectric Cross Section Revisited

    International Nuclear Information System (INIS)

    Haga, A; Nakagawa, K; Kotoku, J; Horikawa, Y

    2015-01-01

    Purpose: The importance of the precision in photoelectric cross-section value increases for recent developed technology such as dual energy computed tomography, in which some reconstruction algorithms require the energy dependence of the photo-absorption in each material composition of human being. In this study, we revisited the photoelectric cross-section calculation by self-consistent relativistic Hartree-Fock (HF) atomic model and compared with that widely distributed as “XCOM database” in National Institute of Standards and Technology, which was evaluated with localdensity approximation for electron-exchange (Fock)z potential. Methods: The photoelectric cross section can be calculated with the electron wave functions in initial atomic state (bound electron) and final continuum state (photoelectron). These electron states were constructed based on the selfconsistent HF calculation, where the repulsive Coulomb potential from the electron charge distribution (Hartree term) and the electron exchange potential with full electromagnetic interaction (Fock term) were included for the electron-electron interaction. The photoelectric cross sections were evaluated for He (Z=2), Be (Z=4), C (Z=6), O (Z=8), and Ne (Z=10) in energy range of 10keV to 1MeV. The Result was compared with XCOM database. Results: The difference of the photoelectric cross section between the present calculation and XCOM database was 8% at a maximum (in 10keV for Be). The agreement tends to be better as the atomic number increases. The contribution from each atomic shell has a considerable discrepancy with XCOM database except for K-shell. However, because the photoelectric cross section arising from K-shell is dominant, the net photoelectric cross section was almost insensitive to the different handling in Fock potential. Conclusion: The photoelectric cross-section program has been developed based on the fully self-consistent relativistic HF atomic model. Due to small effect on the Fock

  14. Revisiting Scaling Relations for Giant Radio Halos in Galaxy Clusters

    Science.gov (United States)

    Cassano, R.; Ettori, S.; Brunetti, G.; Giacintucci, S.; Pratt, G. W.; Venturi, T.; Kale, R.; Dolag, K.; Markevitch, Maxim L.

    2013-01-01

    Many galaxy clusters host megaparsec-scale radio halos, generated by ultrarelativistic electrons in the magnetized intracluster medium. Correlations between the synchrotron power of radio halos and the thermal properties of the hosting clusters were established in the last decade, including the connection between the presence of a halo and cluster mergers. The X-ray luminosity and redshift-limited Extended GMRT Radio Halo Survey provides a rich and unique dataset for statistical studies of the halos. We uniformly analyze the radio and X-ray data for the GMRT cluster sample, and use the new Planck Sunyaev-Zel'dovich (SZ) catalog to revisit the correlations between the power of radio halos and the thermal properties of galaxy clusters. We find that the radio power at 1.4 GHz scales with the cluster X-ray (0.1-2.4 keV) luminosity computed within R(sub 500) as P(sub 1.4) approx. L(2.1+/-0.2) - 500). Our bigger and more homogenous sample confirms that the X-ray luminous (L(sub 500) > 5 × 10(exp 44) erg/s)) clusters branch into two populations-radio halos lie on the correlation, while clusters without radio halos have their radio upper limits well below that correlation. This bimodality remains if we excise cool cores from the X-ray luminosities. We also find that P(sub 1.4) scales with the cluster integrated SZ signal within R(sub 500), measured by Planck, as P(sub 1.4) approx. Y(2.05+/-0.28) - 500), in line with previous findings. However, contrary to previous studies that were limited by incompleteness and small sample size, we find that "SZ-luminous" Y(sub 500) > 6×10(exp -5) Mpc(exp 2) clusters show a bimodal behavior for the presence of radio halos, similar to that in the radio-X-ray diagram. Bimodality of both correlations can be traced to clusters dynamics, with radio halos found exclusively in merging clusters. These results confirm the key role of mergers for the origin of giant radio halos, suggesting that they trigger the relativistic particle acceleration.

  15. Diffusion Monte Carlo Study of Para-Diiodobenzene Polymorphism Revisited.

    Science.gov (United States)

    Hongo, Kenta; Watson, Mark A; Iitaka, Toshiaki; Aspuru-Guzik, Alán; Maezono, Ryo

    2015-03-10

    We revisit our investigation of the diffusion Monte Carlo (DMC) simulation of para-diiodobenzene (p-DIB) molecular crystal polymorphism. [See J. Phys. Chem. Lett. 2010, 1, 1789-1794.] We perform, for the first time, a rigorous study of finite-size effects and choice of nodal surface on the prediction of polymorph stability in molecular crystals using fixed-node DMC. Our calculations are the largest that are currently feasible using the resources of the K-computer and provide insights into the formidable challenge of predicting such properties from first principles. In particular, we show that finite-size effects can influence the trial nodal surface of a small (1 × 1 × 1) simulation cell considerably. Therefore, we repeated our DMC simulations with a 1 × 3 × 3 simulation cell, which is the largest such calculation to date. We used a density functional theory (DFT) nodal surface generated with the PBE functional, and we accumulated statistical samples with ∼6.4 × 10(5) core hours for each polymorph. Our final results predict a polymorph stability that is consistent with experiment, but they also indicate that the results in our previous paper were somewhat fortuitous. We analyze the finite-size errors using model periodic Coulomb (MPC) interactions and kinetic energy corrections, according to the CCMH scheme of Chiesa, Ceperley, Martin, and Holzmann. We investigate the dependence of the finite-size errors on different aspect ratios of the simulation cell (k-mesh convergence) in order to understand how to choose an appropriate ratio for the DMC calculations. Even in the most expensive simulations currently possible, we show that the finite size errors in the DMC total energies are much larger than the energy difference between the two polymorphs, although error cancellation means that the polymorph prediction is accurate. Finally, we found that the T-move scheme is essential for these massive DMC simulations in order to circumvent population explosions and

  16. Dense ceramic catalytic membranes and membrane reactors for energy and environmental applications.

    Science.gov (United States)

    Dong, Xueliang; Jin, Wanqin; Xu, Nanping; Li, Kang

    2011-10-21

    Catalytic membrane reactors which carry out separation and reaction in a single unit are expected to be a promising approach to achieve green and sustainable chemistry with less energy consumption and lower pollution. This article presents a review of the recent progress of dense ceramic catalytic membranes and membrane reactors, and their potential applications in energy and environmental areas. A basic knowledge of catalytic membranes and membrane reactors is first introduced briefly, followed by a short discussion on the membrane materials including their structures, composition and strategies for material development. The configuration of catalytic membranes, the design of membrane reaction processes and the high temperature sealing are also discussed. The performance of catalytic membrane reactors for energy and environmental applications are summarized and typical catalytic membrane reaction processes are presented and discussed. Finally, current challenges and difficulties related to the industrialization of dense ceramic membrane reactors are addressed and possible future research is also outlined.

  17. Cell-free system for synthesizing membrane proteins cell free method for synthesizing membrane proteins

    Science.gov (United States)

    Laible, Philip D; Hanson, Deborah K

    2013-06-04

    The invention provides an in vitro method for producing proteins, membrane proteins, membrane-associated proteins, and soluble proteins that interact with membrane-associated proteins for assembly into an oligomeric complex or that require association with a membrane for proper folding. The method comprises, supplying intracytoplasmic membranes from organisms; modifying protein composition of intracytoplasmic membranes from organism by modifying DNA to delete genes encoding functions of the organism not associated with the formation of the intracytoplasmic membranes; generating appropriate DNA or RNA templates that encode the target protein; and mixing the intracytoplasmic membranes with the template and a transcription/translation-competent cellular extract to cause simultaneous production of the membrane proteins and encapsulation of the membrane proteins within the intracytoplasmic membranes.

  18. Ceramic membranes for gas separation

    Energy Technology Data Exchange (ETDEWEB)

    Vincente-Mingarro, I.M. de; Pitarch, J.A. [Tecnologia y Gestion de la Innovacion, Madrid (Spain)

    1998-11-01

    The project is being carried out jointly by TGI, S.A., CIEMAT and CSIC-ICM to develop and evaluate new inorganic membranes of a ceramic type, with nanometric pore size for separation of contaminants and fuel enrichment, in gas mixtures from coal gasification. In order to achieve both the highest active and selective surface, a candle (150 mm length and 60 mm in diameter), with 30-40 % porosity and pore sizes of {lt}1 {mu}m was developed. The processing steps include the slip-casting of the first layer (porous support) in a way than after thermal treatment (1400-1600{degree}C) the desirable shape dimensions, strength, porosity and pore size were obtained. Then the support was dipped successively (colloidal filtration over the casting porous piece) in an appropriate suspension of alumina with lower grain size. The top layer was obtained by the sol-gel process so that through successive setting and heat treatment the pores were reduced to the nanometre size. CVD and CVI techniques were set up to develop membranes for gas separation with a high selectivity level. Experimental chemical infiltration `Membranes Development` on porous substrates has been achieved on disk and candle-shaped materials. Characterisation was by spectrophotometry (IRS). Kinetic studies of coating in order to find out reproducible conditions at low temperature were also carried out. Uniform recovery over the whole membrane surface is wanted. The CIEMAT`s Hot Gas Separation Plant (HGSP) works with gas mixtures at a maximum design temperature 773 K and pressures up to 50 bar. It comprises: a gas supply unit equipped with flow, temperature and pressure measuring and control systems; a heating system within the membrane which must be leak proof for high pressures; and an in-line gas chromatography system thus allowing the chemical composition of the gas entering, permeated and retained to be measured. 7 figs.

  19. Corrugated Membrane Fuel Cell Structures

    Energy Technology Data Exchange (ETDEWEB)

    Grot, Stephen [President, Ion Power Inc.

    2013-09-30

    One of the most challenging aspects of traditional PEM fuel cell stacks is the difficulty achieving the platinum catalyst utilization target of 0.2 gPt/kWe set forth by the DOE. Good catalyst utilization can be achieved with state-of-the-art catalyst coated membranes (CCM) when low catalyst loadings (<0.3 mg/cm2) are used at a low current. However, when low platinum loadings are used, the peak power density is lower than conventional loadings, requiring a larger total active area and a larger bipolar plate. This results in a lower overall stack power density not meeting the DOE target. By corrugating the fuel cell membrane electrode structure, Ion Power?s goal is to realize both the Pt utilization targets as well as the power density targets of the DOE. This will be achieved by demonstrating a fuel cell single cell (50 cm2) with a twofold increase in the membrane active area over the geometric area of the cell by corrugating the MEA structure. The corrugating structure must be able to demonstrate the target properties of < 10 mOhm-cm2 electrical resistance at > 20 psi compressive strength over the active area, in combination with offering at least 80% of power density that can be achieved by using the same MEA in a flat plate structure. Corrugated membrane fuel cell structures also have the potential to meet DOE power density targets by essentially packaging more membrane area into the same fuel cell volume as compared to conventional stack constructions.

  20. Micro-and/or nano-scale patterned porous membranes, methods of making membranes, and methods of using membranes

    KAUST Repository

    Wang, Xianbin

    2015-01-22

    Embodiments of the present disclosure provide for materials that include a pre-designed patterned, porous membrane (e.g., micro- and/or nano-scale patterned), structures or devices that include a pre-designed patterned, porous membrane, methods of making pre-designed patterned, porous membranes, methods of separation, and the like.